1b886d83cSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2a2c7a983SIngo Molnar /*
358ffa1b4SChristoph Hellwig * BPF JIT compiler
40a14842fSEric Dumazet *
53b58908aSEric Dumazet * Copyright (C) 2011-2013 Eric Dumazet (eric.dumazet@gmail.com)
658ffa1b4SChristoph Hellwig * Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
70a14842fSEric Dumazet */
80a14842fSEric Dumazet #include <linux/netdevice.h>
90a14842fSEric Dumazet #include <linux/filter.h>
10855ddb56SEric Dumazet #include <linux/if_vlan.h>
1171d22d58SDaniel Borkmann #include <linux/bpf.h>
125964b200SAlexei Starovoitov #include <linux/memory.h>
1375ccbef6SBjörn Töpel #include <linux/sort.h>
143dec541bSAlexei Starovoitov #include <asm/extable.h>
15ee3e2469SPeter Zijlstra #include <asm/ftrace.h>
16d1163651SLaura Abbott #include <asm/set_memory.h>
17a493a87fSDaniel Borkmann #include <asm/nospec-branch.h>
185964b200SAlexei Starovoitov #include <asm/text-patching.h>
190a14842fSEric Dumazet
emit_code(u8 * ptr,u32 bytes,unsigned int len)205cccc702SJoe Perches static u8 *emit_code(u8 *ptr, u32 bytes, unsigned int len)
210a14842fSEric Dumazet {
220a14842fSEric Dumazet if (len == 1)
230a14842fSEric Dumazet *ptr = bytes;
240a14842fSEric Dumazet else if (len == 2)
250a14842fSEric Dumazet *(u16 *)ptr = bytes;
260a14842fSEric Dumazet else {
270a14842fSEric Dumazet *(u32 *)ptr = bytes;
280a14842fSEric Dumazet barrier();
290a14842fSEric Dumazet }
300a14842fSEric Dumazet return ptr + len;
310a14842fSEric Dumazet }
320a14842fSEric Dumazet
33b52f00e6SAlexei Starovoitov #define EMIT(bytes, len) \
34ced50fc4SJiri Olsa do { prog = emit_code(prog, bytes, len); } while (0)
350a14842fSEric Dumazet
360a14842fSEric Dumazet #define EMIT1(b1) EMIT(b1, 1)
370a14842fSEric Dumazet #define EMIT2(b1, b2) EMIT((b1) + ((b2) << 8), 2)
380a14842fSEric Dumazet #define EMIT3(b1, b2, b3) EMIT((b1) + ((b2) << 8) + ((b3) << 16), 3)
390a14842fSEric Dumazet #define EMIT4(b1, b2, b3, b4) EMIT((b1) + ((b2) << 8) + ((b3) << 16) + ((b4) << 24), 4)
40a2c7a983SIngo Molnar
4162258278SAlexei Starovoitov #define EMIT1_off32(b1, off) \
4262258278SAlexei Starovoitov do { EMIT1(b1); EMIT(off, 4); } while (0)
4362258278SAlexei Starovoitov #define EMIT2_off32(b1, b2, off) \
4462258278SAlexei Starovoitov do { EMIT2(b1, b2); EMIT(off, 4); } while (0)
4562258278SAlexei Starovoitov #define EMIT3_off32(b1, b2, b3, off) \
4662258278SAlexei Starovoitov do { EMIT3(b1, b2, b3); EMIT(off, 4); } while (0)
4762258278SAlexei Starovoitov #define EMIT4_off32(b1, b2, b3, b4, off) \
4862258278SAlexei Starovoitov do { EMIT4(b1, b2, b3, b4); EMIT(off, 4); } while (0)
490a14842fSEric Dumazet
5058912710SPeter Zijlstra #ifdef CONFIG_X86_KERNEL_IBT
5158912710SPeter Zijlstra #define EMIT_ENDBR() EMIT(gen_endbr(), 4)
5258912710SPeter Zijlstra #else
5358912710SPeter Zijlstra #define EMIT_ENDBR()
5458912710SPeter Zijlstra #endif
5558912710SPeter Zijlstra
is_imm8(int value)565cccc702SJoe Perches static bool is_imm8(int value)
570a14842fSEric Dumazet {
580a14842fSEric Dumazet return value <= 127 && value >= -128;
590a14842fSEric Dumazet }
600a14842fSEric Dumazet
is_simm32(s64 value)615cccc702SJoe Perches static bool is_simm32(s64 value)
620a14842fSEric Dumazet {
6362258278SAlexei Starovoitov return value == (s64)(s32)value;
640a14842fSEric Dumazet }
650a14842fSEric Dumazet
is_uimm32(u64 value)666fe8b9c1SDaniel Borkmann static bool is_uimm32(u64 value)
676fe8b9c1SDaniel Borkmann {
686fe8b9c1SDaniel Borkmann return value == (u64)(u32)value;
696fe8b9c1SDaniel Borkmann }
706fe8b9c1SDaniel Borkmann
71e430f34eSAlexei Starovoitov /* mov dst, src */
72e430f34eSAlexei Starovoitov #define EMIT_mov(DST, SRC) \
73a2c7a983SIngo Molnar do { \
74a2c7a983SIngo Molnar if (DST != SRC) \
75e430f34eSAlexei Starovoitov EMIT3(add_2mod(0x48, DST, SRC), 0x89, add_2reg(0xC0, DST, SRC)); \
760a14842fSEric Dumazet } while (0)
770a14842fSEric Dumazet
bpf_size_to_x86_bytes(int bpf_size)7862258278SAlexei Starovoitov static int bpf_size_to_x86_bytes(int bpf_size)
7962258278SAlexei Starovoitov {
8062258278SAlexei Starovoitov if (bpf_size == BPF_W)
8162258278SAlexei Starovoitov return 4;
8262258278SAlexei Starovoitov else if (bpf_size == BPF_H)
8362258278SAlexei Starovoitov return 2;
8462258278SAlexei Starovoitov else if (bpf_size == BPF_B)
8562258278SAlexei Starovoitov return 1;
8662258278SAlexei Starovoitov else if (bpf_size == BPF_DW)
8762258278SAlexei Starovoitov return 4; /* imm32 */
8862258278SAlexei Starovoitov else
8962258278SAlexei Starovoitov return 0;
9062258278SAlexei Starovoitov }
9162258278SAlexei Starovoitov
92a2c7a983SIngo Molnar /*
93a2c7a983SIngo Molnar * List of x86 cond jumps opcodes (. + s8)
940a14842fSEric Dumazet * Add 0x10 (and an extra 0x0f) to generate far jumps (. + s32)
950a14842fSEric Dumazet */
960a14842fSEric Dumazet #define X86_JB 0x72
970a14842fSEric Dumazet #define X86_JAE 0x73
980a14842fSEric Dumazet #define X86_JE 0x74
990a14842fSEric Dumazet #define X86_JNE 0x75
1000a14842fSEric Dumazet #define X86_JBE 0x76
1010a14842fSEric Dumazet #define X86_JA 0x77
10252afc51eSDaniel Borkmann #define X86_JL 0x7C
10362258278SAlexei Starovoitov #define X86_JGE 0x7D
10452afc51eSDaniel Borkmann #define X86_JLE 0x7E
10562258278SAlexei Starovoitov #define X86_JG 0x7F
1060a14842fSEric Dumazet
107a2c7a983SIngo Molnar /* Pick a register outside of BPF range for JIT internal work */
108959a7579SDaniel Borkmann #define AUX_REG (MAX_BPF_JIT_REG + 1)
109fec56f58SAlexei Starovoitov #define X86_REG_R9 (MAX_BPF_JIT_REG + 2)
11062258278SAlexei Starovoitov
111a2c7a983SIngo Molnar /*
112a2c7a983SIngo Molnar * The following table maps BPF registers to x86-64 registers.
113959a7579SDaniel Borkmann *
114a2c7a983SIngo Molnar * x86-64 register R12 is unused, since if used as base address
115959a7579SDaniel Borkmann * register in load/store instructions, it always needs an
116959a7579SDaniel Borkmann * extra byte of encoding and is callee saved.
117959a7579SDaniel Borkmann *
118fec56f58SAlexei Starovoitov * x86-64 register R9 is not used by BPF programs, but can be used by BPF
119fec56f58SAlexei Starovoitov * trampoline. x86-64 register R10 is used for blinding (if enabled).
12062258278SAlexei Starovoitov */
12162258278SAlexei Starovoitov static const int reg2hex[] = {
122a2c7a983SIngo Molnar [BPF_REG_0] = 0, /* RAX */
123a2c7a983SIngo Molnar [BPF_REG_1] = 7, /* RDI */
124a2c7a983SIngo Molnar [BPF_REG_2] = 6, /* RSI */
125a2c7a983SIngo Molnar [BPF_REG_3] = 2, /* RDX */
126a2c7a983SIngo Molnar [BPF_REG_4] = 1, /* RCX */
127a2c7a983SIngo Molnar [BPF_REG_5] = 0, /* R8 */
128a2c7a983SIngo Molnar [BPF_REG_6] = 3, /* RBX callee saved */
129a2c7a983SIngo Molnar [BPF_REG_7] = 5, /* R13 callee saved */
130a2c7a983SIngo Molnar [BPF_REG_8] = 6, /* R14 callee saved */
131a2c7a983SIngo Molnar [BPF_REG_9] = 7, /* R15 callee saved */
132a2c7a983SIngo Molnar [BPF_REG_FP] = 5, /* RBP readonly */
133a2c7a983SIngo Molnar [BPF_REG_AX] = 2, /* R10 temp register */
134a2c7a983SIngo Molnar [AUX_REG] = 3, /* R11 temp register */
135fec56f58SAlexei Starovoitov [X86_REG_R9] = 1, /* R9 register, 6th function argument */
13662258278SAlexei Starovoitov };
13762258278SAlexei Starovoitov
1383dec541bSAlexei Starovoitov static const int reg2pt_regs[] = {
1393dec541bSAlexei Starovoitov [BPF_REG_0] = offsetof(struct pt_regs, ax),
1403dec541bSAlexei Starovoitov [BPF_REG_1] = offsetof(struct pt_regs, di),
1413dec541bSAlexei Starovoitov [BPF_REG_2] = offsetof(struct pt_regs, si),
1423dec541bSAlexei Starovoitov [BPF_REG_3] = offsetof(struct pt_regs, dx),
1433dec541bSAlexei Starovoitov [BPF_REG_4] = offsetof(struct pt_regs, cx),
1443dec541bSAlexei Starovoitov [BPF_REG_5] = offsetof(struct pt_regs, r8),
1453dec541bSAlexei Starovoitov [BPF_REG_6] = offsetof(struct pt_regs, bx),
1463dec541bSAlexei Starovoitov [BPF_REG_7] = offsetof(struct pt_regs, r13),
1473dec541bSAlexei Starovoitov [BPF_REG_8] = offsetof(struct pt_regs, r14),
1483dec541bSAlexei Starovoitov [BPF_REG_9] = offsetof(struct pt_regs, r15),
1493dec541bSAlexei Starovoitov };
1503dec541bSAlexei Starovoitov
151a2c7a983SIngo Molnar /*
152a2c7a983SIngo Molnar * is_ereg() == true if BPF register 'reg' maps to x86-64 r8..r15
15362258278SAlexei Starovoitov * which need extra byte of encoding.
15462258278SAlexei Starovoitov * rax,rcx,...,rbp have simpler encoding
15562258278SAlexei Starovoitov */
is_ereg(u32 reg)1565cccc702SJoe Perches static bool is_ereg(u32 reg)
15762258278SAlexei Starovoitov {
158d148134bSJoe Perches return (1 << reg) & (BIT(BPF_REG_5) |
159d148134bSJoe Perches BIT(AUX_REG) |
160d148134bSJoe Perches BIT(BPF_REG_7) |
161d148134bSJoe Perches BIT(BPF_REG_8) |
162959a7579SDaniel Borkmann BIT(BPF_REG_9) |
163fec56f58SAlexei Starovoitov BIT(X86_REG_R9) |
164959a7579SDaniel Borkmann BIT(BPF_REG_AX));
16562258278SAlexei Starovoitov }
16662258278SAlexei Starovoitov
167aee194b1SLuke Nelson /*
168aee194b1SLuke Nelson * is_ereg_8l() == true if BPF register 'reg' is mapped to access x86-64
169aee194b1SLuke Nelson * lower 8-bit registers dil,sil,bpl,spl,r8b..r15b, which need extra byte
170aee194b1SLuke Nelson * of encoding. al,cl,dl,bl have simpler encoding.
171aee194b1SLuke Nelson */
is_ereg_8l(u32 reg)172aee194b1SLuke Nelson static bool is_ereg_8l(u32 reg)
173aee194b1SLuke Nelson {
174aee194b1SLuke Nelson return is_ereg(reg) ||
175aee194b1SLuke Nelson (1 << reg) & (BIT(BPF_REG_1) |
176aee194b1SLuke Nelson BIT(BPF_REG_2) |
177aee194b1SLuke Nelson BIT(BPF_REG_FP));
178aee194b1SLuke Nelson }
179aee194b1SLuke Nelson
is_axreg(u32 reg)180de0a444dSDaniel Borkmann static bool is_axreg(u32 reg)
181de0a444dSDaniel Borkmann {
182de0a444dSDaniel Borkmann return reg == BPF_REG_0;
183de0a444dSDaniel Borkmann }
184de0a444dSDaniel Borkmann
185a2c7a983SIngo Molnar /* Add modifiers if 'reg' maps to x86-64 registers R8..R15 */
add_1mod(u8 byte,u32 reg)1865cccc702SJoe Perches static u8 add_1mod(u8 byte, u32 reg)
18762258278SAlexei Starovoitov {
18862258278SAlexei Starovoitov if (is_ereg(reg))
18962258278SAlexei Starovoitov byte |= 1;
19062258278SAlexei Starovoitov return byte;
19162258278SAlexei Starovoitov }
19262258278SAlexei Starovoitov
add_2mod(u8 byte,u32 r1,u32 r2)1935cccc702SJoe Perches static u8 add_2mod(u8 byte, u32 r1, u32 r2)
19462258278SAlexei Starovoitov {
19562258278SAlexei Starovoitov if (is_ereg(r1))
19662258278SAlexei Starovoitov byte |= 1;
19762258278SAlexei Starovoitov if (is_ereg(r2))
19862258278SAlexei Starovoitov byte |= 4;
19962258278SAlexei Starovoitov return byte;
20062258278SAlexei Starovoitov }
20162258278SAlexei Starovoitov
202a2c7a983SIngo Molnar /* Encode 'dst_reg' register into x86-64 opcode 'byte' */
add_1reg(u8 byte,u32 dst_reg)2035cccc702SJoe Perches static u8 add_1reg(u8 byte, u32 dst_reg)
20462258278SAlexei Starovoitov {
205e430f34eSAlexei Starovoitov return byte + reg2hex[dst_reg];
20662258278SAlexei Starovoitov }
20762258278SAlexei Starovoitov
208a2c7a983SIngo Molnar /* Encode 'dst_reg' and 'src_reg' registers into x86-64 opcode 'byte' */
add_2reg(u8 byte,u32 dst_reg,u32 src_reg)2095cccc702SJoe Perches static u8 add_2reg(u8 byte, u32 dst_reg, u32 src_reg)
21062258278SAlexei Starovoitov {
211e430f34eSAlexei Starovoitov return byte + reg2hex[dst_reg] + (reg2hex[src_reg] << 3);
21262258278SAlexei Starovoitov }
21362258278SAlexei Starovoitov
214e5f02cacSBrendan Jackman /* Some 1-byte opcodes for binary ALU operations */
215e5f02cacSBrendan Jackman static u8 simple_alu_opcodes[] = {
216e5f02cacSBrendan Jackman [BPF_ADD] = 0x01,
217e5f02cacSBrendan Jackman [BPF_SUB] = 0x29,
218e5f02cacSBrendan Jackman [BPF_AND] = 0x21,
219e5f02cacSBrendan Jackman [BPF_OR] = 0x09,
220e5f02cacSBrendan Jackman [BPF_XOR] = 0x31,
221e5f02cacSBrendan Jackman [BPF_LSH] = 0xE0,
222e5f02cacSBrendan Jackman [BPF_RSH] = 0xE8,
223e5f02cacSBrendan Jackman [BPF_ARSH] = 0xF8,
224e5f02cacSBrendan Jackman };
225e5f02cacSBrendan Jackman
jit_fill_hole(void * area,unsigned int size)226738cbe72SDaniel Borkmann static void jit_fill_hole(void *area, unsigned int size)
227738cbe72SDaniel Borkmann {
228a2c7a983SIngo Molnar /* Fill whole space with INT3 instructions */
229738cbe72SDaniel Borkmann memset(area, 0xcc, size);
230738cbe72SDaniel Borkmann }
231738cbe72SDaniel Borkmann
bpf_arch_text_invalidate(void * dst,size_t len)232fe736565SSong Liu int bpf_arch_text_invalidate(void *dst, size_t len)
233fe736565SSong Liu {
234fe736565SSong Liu return IS_ERR_OR_NULL(text_poke_set(dst, 0xcc, len));
235fe736565SSong Liu }
236fe736565SSong Liu
237f3c2af7bSAlexei Starovoitov struct jit_context {
238a2c7a983SIngo Molnar int cleanup_addr; /* Epilogue code offset */
239dceba081SPeter Zijlstra
240dceba081SPeter Zijlstra /*
241dceba081SPeter Zijlstra * Program specific offsets of labels in the code; these rely on the
242dceba081SPeter Zijlstra * JIT doing at least 2 passes, recording the position on the first
243dceba081SPeter Zijlstra * pass, only to generate the correct offset on the second pass.
244dceba081SPeter Zijlstra */
245dceba081SPeter Zijlstra int tail_call_direct_label;
246dceba081SPeter Zijlstra int tail_call_indirect_label;
247f3c2af7bSAlexei Starovoitov };
248f3c2af7bSAlexei Starovoitov
249a2c7a983SIngo Molnar /* Maximum number of bytes emitted while JITing one eBPF insn */
250e0ee9c12SAlexei Starovoitov #define BPF_MAX_INSN_SIZE 128
251e0ee9c12SAlexei Starovoitov #define BPF_INSN_SAFETY 64
2524b3da77bSDaniel Borkmann
2534b3da77bSDaniel Borkmann /* Number of bytes emit_patch() needs to generate instructions */
2544b3da77bSDaniel Borkmann #define X86_PATCH_SIZE 5
255ebf7d1f5SMaciej Fijalkowski /* Number of bytes that will be skipped on tailcall */
25658912710SPeter Zijlstra #define X86_TAIL_CALL_OFFSET (11 + ENDBR_INSN_SIZE)
257e0ee9c12SAlexei Starovoitov
push_callee_regs(u8 ** pprog,bool * callee_regs_used)258ebf7d1f5SMaciej Fijalkowski static void push_callee_regs(u8 **pprog, bool *callee_regs_used)
259ebf7d1f5SMaciej Fijalkowski {
260ebf7d1f5SMaciej Fijalkowski u8 *prog = *pprog;
261ebf7d1f5SMaciej Fijalkowski
262ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[0])
263ebf7d1f5SMaciej Fijalkowski EMIT1(0x53); /* push rbx */
264ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[1])
265ebf7d1f5SMaciej Fijalkowski EMIT2(0x41, 0x55); /* push r13 */
266ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[2])
267ebf7d1f5SMaciej Fijalkowski EMIT2(0x41, 0x56); /* push r14 */
268ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[3])
269ebf7d1f5SMaciej Fijalkowski EMIT2(0x41, 0x57); /* push r15 */
270ebf7d1f5SMaciej Fijalkowski *pprog = prog;
271ebf7d1f5SMaciej Fijalkowski }
272ebf7d1f5SMaciej Fijalkowski
pop_callee_regs(u8 ** pprog,bool * callee_regs_used)273ebf7d1f5SMaciej Fijalkowski static void pop_callee_regs(u8 **pprog, bool *callee_regs_used)
274ebf7d1f5SMaciej Fijalkowski {
275ebf7d1f5SMaciej Fijalkowski u8 *prog = *pprog;
276ebf7d1f5SMaciej Fijalkowski
277ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[3])
278ebf7d1f5SMaciej Fijalkowski EMIT2(0x41, 0x5F); /* pop r15 */
279ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[2])
280ebf7d1f5SMaciej Fijalkowski EMIT2(0x41, 0x5E); /* pop r14 */
281ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[1])
282ebf7d1f5SMaciej Fijalkowski EMIT2(0x41, 0x5D); /* pop r13 */
283ebf7d1f5SMaciej Fijalkowski if (callee_regs_used[0])
284ebf7d1f5SMaciej Fijalkowski EMIT1(0x5B); /* pop rbx */
285ebf7d1f5SMaciej Fijalkowski *pprog = prog;
286ebf7d1f5SMaciej Fijalkowski }
287b52f00e6SAlexei Starovoitov
288a2c7a983SIngo Molnar /*
289ebf7d1f5SMaciej Fijalkowski * Emit x86-64 prologue code for BPF program.
290ebf7d1f5SMaciej Fijalkowski * bpf_tail_call helper will skip the first X86_TAIL_CALL_OFFSET bytes
291ebf7d1f5SMaciej Fijalkowski * while jumping to another program
292b52f00e6SAlexei Starovoitov */
emit_prologue(u8 ** pprog,u32 stack_depth,bool ebpf_from_cbpf,bool tail_call_reachable,bool is_subprog)293ebf7d1f5SMaciej Fijalkowski static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf,
294ebf7d1f5SMaciej Fijalkowski bool tail_call_reachable, bool is_subprog)
2950a14842fSEric Dumazet {
296b52f00e6SAlexei Starovoitov u8 *prog = *pprog;
2970a14842fSEric Dumazet
2989fd4a39dSAlexei Starovoitov /* BPF trampoline can be made to work without these nops,
2999fd4a39dSAlexei Starovoitov * but let's waste 5 bytes for now and optimize later
3009fd4a39dSAlexei Starovoitov */
30158912710SPeter Zijlstra EMIT_ENDBR();
302ced50fc4SJiri Olsa memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
303ced50fc4SJiri Olsa prog += X86_PATCH_SIZE;
304ebf7d1f5SMaciej Fijalkowski if (!ebpf_from_cbpf) {
305ebf7d1f5SMaciej Fijalkowski if (tail_call_reachable && !is_subprog)
306ebf7d1f5SMaciej Fijalkowski EMIT2(0x31, 0xC0); /* xor eax, eax */
307ebf7d1f5SMaciej Fijalkowski else
308ebf7d1f5SMaciej Fijalkowski EMIT2(0x66, 0x90); /* nop2 */
309ebf7d1f5SMaciej Fijalkowski }
310fe8d9571SAlexei Starovoitov EMIT1(0x55); /* push rbp */
311fe8d9571SAlexei Starovoitov EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
31258912710SPeter Zijlstra
31358912710SPeter Zijlstra /* X86_TAIL_CALL_OFFSET is here */
31458912710SPeter Zijlstra EMIT_ENDBR();
31558912710SPeter Zijlstra
316fe8d9571SAlexei Starovoitov /* sub rsp, rounded_stack_depth */
3174d0b8c0bSMaciej Fijalkowski if (stack_depth)
318fe8d9571SAlexei Starovoitov EMIT3_off32(0x48, 0x81, 0xEC, round_up(stack_depth, 8));
319ebf7d1f5SMaciej Fijalkowski if (tail_call_reachable)
320ebf7d1f5SMaciej Fijalkowski EMIT1(0x50); /* push rax */
321b52f00e6SAlexei Starovoitov *pprog = prog;
322b52f00e6SAlexei Starovoitov }
323b52f00e6SAlexei Starovoitov
emit_patch(u8 ** pprog,void * func,void * ip,u8 opcode)324428d5df1SDaniel Borkmann static int emit_patch(u8 **pprog, void *func, void *ip, u8 opcode)
325428d5df1SDaniel Borkmann {
326428d5df1SDaniel Borkmann u8 *prog = *pprog;
327428d5df1SDaniel Borkmann s64 offset;
328428d5df1SDaniel Borkmann
329428d5df1SDaniel Borkmann offset = func - (ip + X86_PATCH_SIZE);
330428d5df1SDaniel Borkmann if (!is_simm32(offset)) {
331428d5df1SDaniel Borkmann pr_err("Target call %p is out of range\n", func);
332428d5df1SDaniel Borkmann return -ERANGE;
333428d5df1SDaniel Borkmann }
334428d5df1SDaniel Borkmann EMIT1_off32(opcode, offset);
335428d5df1SDaniel Borkmann *pprog = prog;
336428d5df1SDaniel Borkmann return 0;
337428d5df1SDaniel Borkmann }
338428d5df1SDaniel Borkmann
emit_call(u8 ** pprog,void * func,void * ip)339428d5df1SDaniel Borkmann static int emit_call(u8 **pprog, void *func, void *ip)
340428d5df1SDaniel Borkmann {
341428d5df1SDaniel Borkmann return emit_patch(pprog, func, ip, 0xE8);
342428d5df1SDaniel Borkmann }
343428d5df1SDaniel Borkmann
emit_rsb_call(u8 ** pprog,void * func,void * ip)344b2e9dfe5SThomas Gleixner static int emit_rsb_call(u8 **pprog, void *func, void *ip)
345b2e9dfe5SThomas Gleixner {
346b2e9dfe5SThomas Gleixner OPTIMIZER_HIDE_VAR(func);
3473f9d57c7SUros Bizjak ip += x86_call_depth_emit_accounting(pprog, func);
348b2e9dfe5SThomas Gleixner return emit_patch(pprog, func, ip, 0xE8);
349b2e9dfe5SThomas Gleixner }
350b2e9dfe5SThomas Gleixner
emit_jump(u8 ** pprog,void * func,void * ip)351428d5df1SDaniel Borkmann static int emit_jump(u8 **pprog, void *func, void *ip)
352428d5df1SDaniel Borkmann {
353428d5df1SDaniel Borkmann return emit_patch(pprog, func, ip, 0xE9);
354428d5df1SDaniel Borkmann }
355428d5df1SDaniel Borkmann
__bpf_arch_text_poke(void * ip,enum bpf_text_poke_type t,void * old_addr,void * new_addr)356428d5df1SDaniel Borkmann static int __bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
3571022a549SSong Liu void *old_addr, void *new_addr)
358428d5df1SDaniel Borkmann {
359a89dfde3SPeter Zijlstra const u8 *nop_insn = x86_nops[5];
360b553a6ecSDaniel Borkmann u8 old_insn[X86_PATCH_SIZE];
361b553a6ecSDaniel Borkmann u8 new_insn[X86_PATCH_SIZE];
362428d5df1SDaniel Borkmann u8 *prog;
363428d5df1SDaniel Borkmann int ret;
364428d5df1SDaniel Borkmann
365428d5df1SDaniel Borkmann memcpy(old_insn, nop_insn, X86_PATCH_SIZE);
366b553a6ecSDaniel Borkmann if (old_addr) {
367428d5df1SDaniel Borkmann prog = old_insn;
368b553a6ecSDaniel Borkmann ret = t == BPF_MOD_CALL ?
369b553a6ecSDaniel Borkmann emit_call(&prog, old_addr, ip) :
370b553a6ecSDaniel Borkmann emit_jump(&prog, old_addr, ip);
371428d5df1SDaniel Borkmann if (ret)
372428d5df1SDaniel Borkmann return ret;
373428d5df1SDaniel Borkmann }
374b553a6ecSDaniel Borkmann
375428d5df1SDaniel Borkmann memcpy(new_insn, nop_insn, X86_PATCH_SIZE);
376b553a6ecSDaniel Borkmann if (new_addr) {
377b553a6ecSDaniel Borkmann prog = new_insn;
378b553a6ecSDaniel Borkmann ret = t == BPF_MOD_CALL ?
379b553a6ecSDaniel Borkmann emit_call(&prog, new_addr, ip) :
380b553a6ecSDaniel Borkmann emit_jump(&prog, new_addr, ip);
381428d5df1SDaniel Borkmann if (ret)
382428d5df1SDaniel Borkmann return ret;
383428d5df1SDaniel Borkmann }
384428d5df1SDaniel Borkmann
385428d5df1SDaniel Borkmann ret = -EBUSY;
386428d5df1SDaniel Borkmann mutex_lock(&text_mutex);
387428d5df1SDaniel Borkmann if (memcmp(ip, old_insn, X86_PATCH_SIZE))
388428d5df1SDaniel Borkmann goto out;
389ebf7d1f5SMaciej Fijalkowski ret = 1;
390b553a6ecSDaniel Borkmann if (memcmp(ip, new_insn, X86_PATCH_SIZE)) {
391428d5df1SDaniel Borkmann text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL);
392428d5df1SDaniel Borkmann ret = 0;
393ebf7d1f5SMaciej Fijalkowski }
394428d5df1SDaniel Borkmann out:
395428d5df1SDaniel Borkmann mutex_unlock(&text_mutex);
396428d5df1SDaniel Borkmann return ret;
397428d5df1SDaniel Borkmann }
398428d5df1SDaniel Borkmann
bpf_arch_text_poke(void * ip,enum bpf_text_poke_type t,void * old_addr,void * new_addr)399428d5df1SDaniel Borkmann int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
400428d5df1SDaniel Borkmann void *old_addr, void *new_addr)
401428d5df1SDaniel Borkmann {
402428d5df1SDaniel Borkmann if (!is_kernel_text((long)ip) &&
403428d5df1SDaniel Borkmann !is_bpf_text_address((long)ip))
404428d5df1SDaniel Borkmann /* BPF poking in modules is not supported */
405428d5df1SDaniel Borkmann return -EINVAL;
406428d5df1SDaniel Borkmann
40758912710SPeter Zijlstra /*
40858912710SPeter Zijlstra * See emit_prologue(), for IBT builds the trampoline hook is preceded
40958912710SPeter Zijlstra * with an ENDBR instruction.
41058912710SPeter Zijlstra */
41158912710SPeter Zijlstra if (is_endbr(*(u32 *)ip))
41258912710SPeter Zijlstra ip += ENDBR_INSN_SIZE;
41358912710SPeter Zijlstra
4141022a549SSong Liu return __bpf_arch_text_poke(ip, t, old_addr, new_addr);
415428d5df1SDaniel Borkmann }
416428d5df1SDaniel Borkmann
41787c87ecdSPeter Zijlstra #define EMIT_LFENCE() EMIT3(0x0F, 0xAE, 0xE8)
41887c87ecdSPeter Zijlstra
emit_indirect_jump(u8 ** pprog,int reg,u8 * ip)41987c87ecdSPeter Zijlstra static void emit_indirect_jump(u8 **pprog, int reg, u8 *ip)
42087c87ecdSPeter Zijlstra {
42187c87ecdSPeter Zijlstra u8 *prog = *pprog;
42287c87ecdSPeter Zijlstra
423d45476d9SPeter Zijlstra (Intel) if (cpu_feature_enabled(X86_FEATURE_RETPOLINE_LFENCE)) {
42487c87ecdSPeter Zijlstra EMIT_LFENCE();
42587c87ecdSPeter Zijlstra EMIT2(0xFF, 0xE0 + reg);
42687c87ecdSPeter Zijlstra } else if (cpu_feature_enabled(X86_FEATURE_RETPOLINE)) {
427be8a0965SPeter Zijlstra OPTIMIZER_HIDE_VAR(reg);
4283b6c1747SPeter Zijlstra if (cpu_feature_enabled(X86_FEATURE_CALL_DEPTH))
4293b6c1747SPeter Zijlstra emit_jump(&prog, &__x86_indirect_jump_thunk_array[reg], ip);
4303b6c1747SPeter Zijlstra else
43187c87ecdSPeter Zijlstra emit_jump(&prog, &__x86_indirect_thunk_array[reg], ip);
432369ae6ffSPeter Zijlstra } else {
4338c03af3eSPeter Zijlstra EMIT2(0xFF, 0xE0 + reg); /* jmp *%\reg */
4348c03af3eSPeter Zijlstra if (IS_ENABLED(CONFIG_RETPOLINE) || IS_ENABLED(CONFIG_SLS))
4358c03af3eSPeter Zijlstra EMIT1(0xCC); /* int3 */
436369ae6ffSPeter Zijlstra }
43787c87ecdSPeter Zijlstra
43887c87ecdSPeter Zijlstra *pprog = prog;
43987c87ecdSPeter Zijlstra }
44087c87ecdSPeter Zijlstra
emit_return(u8 ** pprog,u8 * ip)441d77cfe59SPeter Zijlstra static void emit_return(u8 **pprog, u8 *ip)
442d77cfe59SPeter Zijlstra {
443d77cfe59SPeter Zijlstra u8 *prog = *pprog;
444d77cfe59SPeter Zijlstra
445d77cfe59SPeter Zijlstra if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) {
446770ae1b7SPeter Zijlstra emit_jump(&prog, x86_return_thunk, ip);
447d77cfe59SPeter Zijlstra } else {
448d77cfe59SPeter Zijlstra EMIT1(0xC3); /* ret */
449d77cfe59SPeter Zijlstra if (IS_ENABLED(CONFIG_SLS))
450d77cfe59SPeter Zijlstra EMIT1(0xCC); /* int3 */
451d77cfe59SPeter Zijlstra }
452b52f00e6SAlexei Starovoitov
453b52f00e6SAlexei Starovoitov *pprog = prog;
454b52f00e6SAlexei Starovoitov }
455b52f00e6SAlexei Starovoitov
456a2c7a983SIngo Molnar /*
457a2c7a983SIngo Molnar * Generate the following code:
458a2c7a983SIngo Molnar *
459b52f00e6SAlexei Starovoitov * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ...
460b52f00e6SAlexei Starovoitov * if (index >= array->map.max_entries)
461b52f00e6SAlexei Starovoitov * goto out;
462ebf7f6f0STiezhu Yang * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
463b52f00e6SAlexei Starovoitov * goto out;
4642a36f0b9SWang Nan * prog = array->ptrs[index];
465b52f00e6SAlexei Starovoitov * if (prog == NULL)
466b52f00e6SAlexei Starovoitov * goto out;
467b52f00e6SAlexei Starovoitov * goto *(prog->bpf_func + prologue_size);
468b52f00e6SAlexei Starovoitov * out:
469b52f00e6SAlexei Starovoitov */
emit_bpf_tail_call_indirect(u8 ** pprog,bool * callee_regs_used,u32 stack_depth,u8 * ip,struct jit_context * ctx)470ebf7d1f5SMaciej Fijalkowski static void emit_bpf_tail_call_indirect(u8 **pprog, bool *callee_regs_used,
471dceba081SPeter Zijlstra u32 stack_depth, u8 *ip,
472dceba081SPeter Zijlstra struct jit_context *ctx)
473b52f00e6SAlexei Starovoitov {
474ebf7d1f5SMaciej Fijalkowski int tcc_off = -4 - round_up(stack_depth, 8);
475dceba081SPeter Zijlstra u8 *prog = *pprog, *start = *pprog;
476dceba081SPeter Zijlstra int offset;
4774d0b8c0bSMaciej Fijalkowski
478a2c7a983SIngo Molnar /*
479a2c7a983SIngo Molnar * rdi - pointer to ctx
480b52f00e6SAlexei Starovoitov * rsi - pointer to bpf_array
481b52f00e6SAlexei Starovoitov * rdx - index in bpf_array
482b52f00e6SAlexei Starovoitov */
483b52f00e6SAlexei Starovoitov
484a2c7a983SIngo Molnar /*
485a2c7a983SIngo Molnar * if (index >= array->map.max_entries)
486b52f00e6SAlexei Starovoitov * goto out;
487b52f00e6SAlexei Starovoitov */
48890caccddSAlexei Starovoitov EMIT2(0x89, 0xD2); /* mov edx, edx */
48990caccddSAlexei Starovoitov EMIT3(0x39, 0x56, /* cmp dword ptr [rsi + 16], edx */
490b52f00e6SAlexei Starovoitov offsetof(struct bpf_array, map.max_entries));
491dceba081SPeter Zijlstra
492dceba081SPeter Zijlstra offset = ctx->tail_call_indirect_label - (prog + 2 - start);
493dceba081SPeter Zijlstra EMIT2(X86_JBE, offset); /* jbe out */
494b52f00e6SAlexei Starovoitov
495a2c7a983SIngo Molnar /*
496ebf7f6f0STiezhu Yang * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
497b52f00e6SAlexei Starovoitov * goto out;
498b52f00e6SAlexei Starovoitov */
499ebf7d1f5SMaciej Fijalkowski EMIT2_off32(0x8B, 0x85, tcc_off); /* mov eax, dword ptr [rbp - tcc_off] */
500b52f00e6SAlexei Starovoitov EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
501dceba081SPeter Zijlstra
502dceba081SPeter Zijlstra offset = ctx->tail_call_indirect_label - (prog + 2 - start);
503ebf7f6f0STiezhu Yang EMIT2(X86_JAE, offset); /* jae out */
504b52f00e6SAlexei Starovoitov EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
505ebf7d1f5SMaciej Fijalkowski EMIT2_off32(0x89, 0x85, tcc_off); /* mov dword ptr [rbp - tcc_off], eax */
506b52f00e6SAlexei Starovoitov
5072a36f0b9SWang Nan /* prog = array->ptrs[index]; */
5080d4ddce3SMaciej Fijalkowski EMIT4_off32(0x48, 0x8B, 0x8C, 0xD6, /* mov rcx, [rsi + rdx * 8 + offsetof(...)] */
5092a36f0b9SWang Nan offsetof(struct bpf_array, ptrs));
510b52f00e6SAlexei Starovoitov
511a2c7a983SIngo Molnar /*
512a2c7a983SIngo Molnar * if (prog == NULL)
513b52f00e6SAlexei Starovoitov * goto out;
514b52f00e6SAlexei Starovoitov */
5150d4ddce3SMaciej Fijalkowski EMIT3(0x48, 0x85, 0xC9); /* test rcx,rcx */
516b52f00e6SAlexei Starovoitov
517dceba081SPeter Zijlstra offset = ctx->tail_call_indirect_label - (prog + 2 - start);
518dceba081SPeter Zijlstra EMIT2(X86_JE, offset); /* je out */
519dceba081SPeter Zijlstra
520dceba081SPeter Zijlstra pop_callee_regs(&prog, callee_regs_used);
521ebf7d1f5SMaciej Fijalkowski
522ebf7d1f5SMaciej Fijalkowski EMIT1(0x58); /* pop rax */
5234d0b8c0bSMaciej Fijalkowski if (stack_depth)
524ebf7d1f5SMaciej Fijalkowski EMIT3_off32(0x48, 0x81, 0xC4, /* add rsp, sd */
525ebf7d1f5SMaciej Fijalkowski round_up(stack_depth, 8));
526ebf7d1f5SMaciej Fijalkowski
527ebf7d1f5SMaciej Fijalkowski /* goto *(prog->bpf_func + X86_TAIL_CALL_OFFSET); */
5280d4ddce3SMaciej Fijalkowski EMIT4(0x48, 0x8B, 0x49, /* mov rcx, qword ptr [rcx + 32] */
529b52f00e6SAlexei Starovoitov offsetof(struct bpf_prog, bpf_func));
530ebf7d1f5SMaciej Fijalkowski EMIT4(0x48, 0x83, 0xC1, /* add rcx, X86_TAIL_CALL_OFFSET */
531ebf7d1f5SMaciej Fijalkowski X86_TAIL_CALL_OFFSET);
532a2c7a983SIngo Molnar /*
5330d4ddce3SMaciej Fijalkowski * Now we're ready to jump into next BPF program
534b52f00e6SAlexei Starovoitov * rdi == ctx (1st arg)
535ebf7d1f5SMaciej Fijalkowski * rcx == prog->bpf_func + X86_TAIL_CALL_OFFSET
536b52f00e6SAlexei Starovoitov */
53787c87ecdSPeter Zijlstra emit_indirect_jump(&prog, 1 /* rcx */, ip + (prog - start));
538b52f00e6SAlexei Starovoitov
539b52f00e6SAlexei Starovoitov /* out: */
540dceba081SPeter Zijlstra ctx->tail_call_indirect_label = prog - start;
541b52f00e6SAlexei Starovoitov *pprog = prog;
542b52f00e6SAlexei Starovoitov }
543b52f00e6SAlexei Starovoitov
emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor * poke,u8 ** pprog,u8 * ip,bool * callee_regs_used,u32 stack_depth,struct jit_context * ctx)544428d5df1SDaniel Borkmann static void emit_bpf_tail_call_direct(struct bpf_jit_poke_descriptor *poke,
545dceba081SPeter Zijlstra u8 **pprog, u8 *ip,
546dceba081SPeter Zijlstra bool *callee_regs_used, u32 stack_depth,
547dceba081SPeter Zijlstra struct jit_context *ctx)
548428d5df1SDaniel Borkmann {
549ebf7d1f5SMaciej Fijalkowski int tcc_off = -4 - round_up(stack_depth, 8);
550dceba081SPeter Zijlstra u8 *prog = *pprog, *start = *pprog;
551dceba081SPeter Zijlstra int offset;
552ebf7d1f5SMaciej Fijalkowski
553428d5df1SDaniel Borkmann /*
554ebf7f6f0STiezhu Yang * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
555428d5df1SDaniel Borkmann * goto out;
556428d5df1SDaniel Borkmann */
557ebf7d1f5SMaciej Fijalkowski EMIT2_off32(0x8B, 0x85, tcc_off); /* mov eax, dword ptr [rbp - tcc_off] */
558428d5df1SDaniel Borkmann EMIT3(0x83, 0xF8, MAX_TAIL_CALL_CNT); /* cmp eax, MAX_TAIL_CALL_CNT */
559dceba081SPeter Zijlstra
560dceba081SPeter Zijlstra offset = ctx->tail_call_direct_label - (prog + 2 - start);
561ebf7f6f0STiezhu Yang EMIT2(X86_JAE, offset); /* jae out */
562428d5df1SDaniel Borkmann EMIT3(0x83, 0xC0, 0x01); /* add eax, 1 */
563ebf7d1f5SMaciej Fijalkowski EMIT2_off32(0x89, 0x85, tcc_off); /* mov dword ptr [rbp - tcc_off], eax */
564428d5df1SDaniel Borkmann
565dceba081SPeter Zijlstra poke->tailcall_bypass = ip + (prog - start);
566ebf7d1f5SMaciej Fijalkowski poke->adj_off = X86_TAIL_CALL_OFFSET;
567dceba081SPeter Zijlstra poke->tailcall_target = ip + ctx->tail_call_direct_label - X86_PATCH_SIZE;
568ebf7d1f5SMaciej Fijalkowski poke->bypass_addr = (u8 *)poke->tailcall_target + X86_PATCH_SIZE;
569ebf7d1f5SMaciej Fijalkowski
570ebf7d1f5SMaciej Fijalkowski emit_jump(&prog, (u8 *)poke->tailcall_target + X86_PATCH_SIZE,
571ebf7d1f5SMaciej Fijalkowski poke->tailcall_bypass);
572ebf7d1f5SMaciej Fijalkowski
573dceba081SPeter Zijlstra pop_callee_regs(&prog, callee_regs_used);
574ebf7d1f5SMaciej Fijalkowski EMIT1(0x58); /* pop rax */
5754d0b8c0bSMaciej Fijalkowski if (stack_depth)
576ebf7d1f5SMaciej Fijalkowski EMIT3_off32(0x48, 0x81, 0xC4, round_up(stack_depth, 8));
577428d5df1SDaniel Borkmann
578a89dfde3SPeter Zijlstra memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
579428d5df1SDaniel Borkmann prog += X86_PATCH_SIZE;
580dceba081SPeter Zijlstra
581428d5df1SDaniel Borkmann /* out: */
582dceba081SPeter Zijlstra ctx->tail_call_direct_label = prog - start;
583428d5df1SDaniel Borkmann
584428d5df1SDaniel Borkmann *pprog = prog;
585428d5df1SDaniel Borkmann }
586428d5df1SDaniel Borkmann
bpf_tail_call_direct_fixup(struct bpf_prog * prog)587428d5df1SDaniel Borkmann static void bpf_tail_call_direct_fixup(struct bpf_prog *prog)
588428d5df1SDaniel Borkmann {
589428d5df1SDaniel Borkmann struct bpf_jit_poke_descriptor *poke;
590428d5df1SDaniel Borkmann struct bpf_array *array;
591428d5df1SDaniel Borkmann struct bpf_prog *target;
592428d5df1SDaniel Borkmann int i, ret;
593428d5df1SDaniel Borkmann
594428d5df1SDaniel Borkmann for (i = 0; i < prog->aux->size_poke_tab; i++) {
595428d5df1SDaniel Borkmann poke = &prog->aux->poke_tab[i];
596f263a814SJohn Fastabend if (poke->aux && poke->aux != prog->aux)
597f263a814SJohn Fastabend continue;
598f263a814SJohn Fastabend
599cf71b174SMaciej Fijalkowski WARN_ON_ONCE(READ_ONCE(poke->tailcall_target_stable));
600428d5df1SDaniel Borkmann
601428d5df1SDaniel Borkmann if (poke->reason != BPF_POKE_REASON_TAIL_CALL)
602428d5df1SDaniel Borkmann continue;
603428d5df1SDaniel Borkmann
604428d5df1SDaniel Borkmann array = container_of(poke->tail_call.map, struct bpf_array, map);
605428d5df1SDaniel Borkmann mutex_lock(&array->aux->poke_mutex);
606428d5df1SDaniel Borkmann target = array->ptrs[poke->tail_call.key];
607428d5df1SDaniel Borkmann if (target) {
608cf71b174SMaciej Fijalkowski ret = __bpf_arch_text_poke(poke->tailcall_target,
609cf71b174SMaciej Fijalkowski BPF_MOD_JUMP, NULL,
610428d5df1SDaniel Borkmann (u8 *)target->bpf_func +
6111022a549SSong Liu poke->adj_off);
612428d5df1SDaniel Borkmann BUG_ON(ret < 0);
613ebf7d1f5SMaciej Fijalkowski ret = __bpf_arch_text_poke(poke->tailcall_bypass,
614ebf7d1f5SMaciej Fijalkowski BPF_MOD_JUMP,
615ebf7d1f5SMaciej Fijalkowski (u8 *)poke->tailcall_target +
6161022a549SSong Liu X86_PATCH_SIZE, NULL);
617ebf7d1f5SMaciej Fijalkowski BUG_ON(ret < 0);
618428d5df1SDaniel Borkmann }
619cf71b174SMaciej Fijalkowski WRITE_ONCE(poke->tailcall_target_stable, true);
620428d5df1SDaniel Borkmann mutex_unlock(&array->aux->poke_mutex);
621428d5df1SDaniel Borkmann }
622428d5df1SDaniel Borkmann }
623428d5df1SDaniel Borkmann
emit_mov_imm32(u8 ** pprog,bool sign_propagate,u32 dst_reg,const u32 imm32)6246fe8b9c1SDaniel Borkmann static void emit_mov_imm32(u8 **pprog, bool sign_propagate,
6256fe8b9c1SDaniel Borkmann u32 dst_reg, const u32 imm32)
6266fe8b9c1SDaniel Borkmann {
6276fe8b9c1SDaniel Borkmann u8 *prog = *pprog;
6286fe8b9c1SDaniel Borkmann u8 b1, b2, b3;
6296fe8b9c1SDaniel Borkmann
630a2c7a983SIngo Molnar /*
631a2c7a983SIngo Molnar * Optimization: if imm32 is positive, use 'mov %eax, imm32'
6326fe8b9c1SDaniel Borkmann * (which zero-extends imm32) to save 2 bytes.
6336fe8b9c1SDaniel Borkmann */
6346fe8b9c1SDaniel Borkmann if (sign_propagate && (s32)imm32 < 0) {
6356fe8b9c1SDaniel Borkmann /* 'mov %rax, imm32' sign extends imm32 */
6366fe8b9c1SDaniel Borkmann b1 = add_1mod(0x48, dst_reg);
6376fe8b9c1SDaniel Borkmann b2 = 0xC7;
6386fe8b9c1SDaniel Borkmann b3 = 0xC0;
6396fe8b9c1SDaniel Borkmann EMIT3_off32(b1, b2, add_1reg(b3, dst_reg), imm32);
6406fe8b9c1SDaniel Borkmann goto done;
6416fe8b9c1SDaniel Borkmann }
6426fe8b9c1SDaniel Borkmann
643a2c7a983SIngo Molnar /*
644a2c7a983SIngo Molnar * Optimization: if imm32 is zero, use 'xor %eax, %eax'
6456fe8b9c1SDaniel Borkmann * to save 3 bytes.
6466fe8b9c1SDaniel Borkmann */
6476fe8b9c1SDaniel Borkmann if (imm32 == 0) {
6486fe8b9c1SDaniel Borkmann if (is_ereg(dst_reg))
6496fe8b9c1SDaniel Borkmann EMIT1(add_2mod(0x40, dst_reg, dst_reg));
6506fe8b9c1SDaniel Borkmann b2 = 0x31; /* xor */
6516fe8b9c1SDaniel Borkmann b3 = 0xC0;
6526fe8b9c1SDaniel Borkmann EMIT2(b2, add_2reg(b3, dst_reg, dst_reg));
6536fe8b9c1SDaniel Borkmann goto done;
6546fe8b9c1SDaniel Borkmann }
6556fe8b9c1SDaniel Borkmann
6566fe8b9c1SDaniel Borkmann /* mov %eax, imm32 */
6576fe8b9c1SDaniel Borkmann if (is_ereg(dst_reg))
6586fe8b9c1SDaniel Borkmann EMIT1(add_1mod(0x40, dst_reg));
6596fe8b9c1SDaniel Borkmann EMIT1_off32(add_1reg(0xB8, dst_reg), imm32);
6606fe8b9c1SDaniel Borkmann done:
6616fe8b9c1SDaniel Borkmann *pprog = prog;
6626fe8b9c1SDaniel Borkmann }
6636fe8b9c1SDaniel Borkmann
emit_mov_imm64(u8 ** pprog,u32 dst_reg,const u32 imm32_hi,const u32 imm32_lo)6646fe8b9c1SDaniel Borkmann static void emit_mov_imm64(u8 **pprog, u32 dst_reg,
6656fe8b9c1SDaniel Borkmann const u32 imm32_hi, const u32 imm32_lo)
6666fe8b9c1SDaniel Borkmann {
6676fe8b9c1SDaniel Borkmann u8 *prog = *pprog;
6686fe8b9c1SDaniel Borkmann
6696fe8b9c1SDaniel Borkmann if (is_uimm32(((u64)imm32_hi << 32) | (u32)imm32_lo)) {
670a2c7a983SIngo Molnar /*
671a2c7a983SIngo Molnar * For emitting plain u32, where sign bit must not be
6726fe8b9c1SDaniel Borkmann * propagated LLVM tends to load imm64 over mov32
6736fe8b9c1SDaniel Borkmann * directly, so save couple of bytes by just doing
6746fe8b9c1SDaniel Borkmann * 'mov %eax, imm32' instead.
6756fe8b9c1SDaniel Borkmann */
6766fe8b9c1SDaniel Borkmann emit_mov_imm32(&prog, false, dst_reg, imm32_lo);
6776fe8b9c1SDaniel Borkmann } else {
6784d854f4fSJiri Olsa /* movabsq rax, imm64 */
6796fe8b9c1SDaniel Borkmann EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
6806fe8b9c1SDaniel Borkmann EMIT(imm32_lo, 4);
6816fe8b9c1SDaniel Borkmann EMIT(imm32_hi, 4);
6826fe8b9c1SDaniel Borkmann }
6836fe8b9c1SDaniel Borkmann
6846fe8b9c1SDaniel Borkmann *pprog = prog;
6856fe8b9c1SDaniel Borkmann }
6866fe8b9c1SDaniel Borkmann
emit_mov_reg(u8 ** pprog,bool is64,u32 dst_reg,u32 src_reg)6874c38e2f3SDaniel Borkmann static void emit_mov_reg(u8 **pprog, bool is64, u32 dst_reg, u32 src_reg)
6884c38e2f3SDaniel Borkmann {
6894c38e2f3SDaniel Borkmann u8 *prog = *pprog;
6904c38e2f3SDaniel Borkmann
6914c38e2f3SDaniel Borkmann if (is64) {
6924c38e2f3SDaniel Borkmann /* mov dst, src */
6934c38e2f3SDaniel Borkmann EMIT_mov(dst_reg, src_reg);
6944c38e2f3SDaniel Borkmann } else {
6954c38e2f3SDaniel Borkmann /* mov32 dst, src */
6964c38e2f3SDaniel Borkmann if (is_ereg(dst_reg) || is_ereg(src_reg))
6974c38e2f3SDaniel Borkmann EMIT1(add_2mod(0x40, dst_reg, src_reg));
6984c38e2f3SDaniel Borkmann EMIT2(0x89, add_2reg(0xC0, dst_reg, src_reg));
6994c38e2f3SDaniel Borkmann }
7004c38e2f3SDaniel Borkmann
7014c38e2f3SDaniel Borkmann *pprog = prog;
7024c38e2f3SDaniel Borkmann }
7034c38e2f3SDaniel Borkmann
emit_movsx_reg(u8 ** pprog,int num_bits,bool is64,u32 dst_reg,u32 src_reg)7048100928cSYonghong Song static void emit_movsx_reg(u8 **pprog, int num_bits, bool is64, u32 dst_reg,
7058100928cSYonghong Song u32 src_reg)
7068100928cSYonghong Song {
7078100928cSYonghong Song u8 *prog = *pprog;
7088100928cSYonghong Song
7098100928cSYonghong Song if (is64) {
7108100928cSYonghong Song /* movs[b,w,l]q dst, src */
7118100928cSYonghong Song if (num_bits == 8)
7128100928cSYonghong Song EMIT4(add_2mod(0x48, src_reg, dst_reg), 0x0f, 0xbe,
7138100928cSYonghong Song add_2reg(0xC0, src_reg, dst_reg));
7148100928cSYonghong Song else if (num_bits == 16)
7158100928cSYonghong Song EMIT4(add_2mod(0x48, src_reg, dst_reg), 0x0f, 0xbf,
7168100928cSYonghong Song add_2reg(0xC0, src_reg, dst_reg));
7178100928cSYonghong Song else if (num_bits == 32)
7188100928cSYonghong Song EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x63,
7198100928cSYonghong Song add_2reg(0xC0, src_reg, dst_reg));
7208100928cSYonghong Song } else {
7218100928cSYonghong Song /* movs[b,w]l dst, src */
7228100928cSYonghong Song if (num_bits == 8) {
7238100928cSYonghong Song EMIT4(add_2mod(0x40, src_reg, dst_reg), 0x0f, 0xbe,
7248100928cSYonghong Song add_2reg(0xC0, src_reg, dst_reg));
7258100928cSYonghong Song } else if (num_bits == 16) {
7268100928cSYonghong Song if (is_ereg(dst_reg) || is_ereg(src_reg))
7278100928cSYonghong Song EMIT1(add_2mod(0x40, src_reg, dst_reg));
7288100928cSYonghong Song EMIT3(add_2mod(0x0f, src_reg, dst_reg), 0xbf,
7298100928cSYonghong Song add_2reg(0xC0, src_reg, dst_reg));
7308100928cSYonghong Song }
7318100928cSYonghong Song }
7328100928cSYonghong Song
7338100928cSYonghong Song *pprog = prog;
7348100928cSYonghong Song }
7358100928cSYonghong Song
73611c11d07SBrendan Jackman /* Emit the suffix (ModR/M etc) for addressing *(ptr_reg + off) and val_reg */
emit_insn_suffix(u8 ** pprog,u32 ptr_reg,u32 val_reg,int off)73711c11d07SBrendan Jackman static void emit_insn_suffix(u8 **pprog, u32 ptr_reg, u32 val_reg, int off)
73811c11d07SBrendan Jackman {
73911c11d07SBrendan Jackman u8 *prog = *pprog;
74011c11d07SBrendan Jackman
74111c11d07SBrendan Jackman if (is_imm8(off)) {
74211c11d07SBrendan Jackman /* 1-byte signed displacement.
74311c11d07SBrendan Jackman *
74411c11d07SBrendan Jackman * If off == 0 we could skip this and save one extra byte, but
74511c11d07SBrendan Jackman * special case of x86 R13 which always needs an offset is not
74611c11d07SBrendan Jackman * worth the hassle
74711c11d07SBrendan Jackman */
74811c11d07SBrendan Jackman EMIT2(add_2reg(0x40, ptr_reg, val_reg), off);
74911c11d07SBrendan Jackman } else {
75011c11d07SBrendan Jackman /* 4-byte signed displacement */
75111c11d07SBrendan Jackman EMIT1_off32(add_2reg(0x80, ptr_reg, val_reg), off);
75211c11d07SBrendan Jackman }
75311c11d07SBrendan Jackman *pprog = prog;
75411c11d07SBrendan Jackman }
75511c11d07SBrendan Jackman
75674007cfcSBrendan Jackman /*
75774007cfcSBrendan Jackman * Emit a REX byte if it will be necessary to address these registers
75874007cfcSBrendan Jackman */
maybe_emit_mod(u8 ** pprog,u32 dst_reg,u32 src_reg,bool is64)75974007cfcSBrendan Jackman static void maybe_emit_mod(u8 **pprog, u32 dst_reg, u32 src_reg, bool is64)
76074007cfcSBrendan Jackman {
76174007cfcSBrendan Jackman u8 *prog = *pprog;
76274007cfcSBrendan Jackman
76374007cfcSBrendan Jackman if (is64)
76474007cfcSBrendan Jackman EMIT1(add_2mod(0x48, dst_reg, src_reg));
76574007cfcSBrendan Jackman else if (is_ereg(dst_reg) || is_ereg(src_reg))
76674007cfcSBrendan Jackman EMIT1(add_2mod(0x40, dst_reg, src_reg));
76774007cfcSBrendan Jackman *pprog = prog;
76874007cfcSBrendan Jackman }
76974007cfcSBrendan Jackman
7706364d7d7SJie Meng /*
7716364d7d7SJie Meng * Similar version of maybe_emit_mod() for a single register
7726364d7d7SJie Meng */
maybe_emit_1mod(u8 ** pprog,u32 reg,bool is64)7736364d7d7SJie Meng static void maybe_emit_1mod(u8 **pprog, u32 reg, bool is64)
7746364d7d7SJie Meng {
7756364d7d7SJie Meng u8 *prog = *pprog;
7766364d7d7SJie Meng
7776364d7d7SJie Meng if (is64)
7786364d7d7SJie Meng EMIT1(add_1mod(0x48, reg));
7796364d7d7SJie Meng else if (is_ereg(reg))
7806364d7d7SJie Meng EMIT1(add_1mod(0x40, reg));
7816364d7d7SJie Meng *pprog = prog;
7826364d7d7SJie Meng }
7836364d7d7SJie Meng
7843b2744e6SAlexei Starovoitov /* LDX: dst_reg = *(u8*)(src_reg + off) */
emit_ldx(u8 ** pprog,u32 size,u32 dst_reg,u32 src_reg,int off)7853b2744e6SAlexei Starovoitov static void emit_ldx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
7863b2744e6SAlexei Starovoitov {
7873b2744e6SAlexei Starovoitov u8 *prog = *pprog;
7883b2744e6SAlexei Starovoitov
7893b2744e6SAlexei Starovoitov switch (size) {
7903b2744e6SAlexei Starovoitov case BPF_B:
7913b2744e6SAlexei Starovoitov /* Emit 'movzx rax, byte ptr [rax + off]' */
7923b2744e6SAlexei Starovoitov EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB6);
7933b2744e6SAlexei Starovoitov break;
7943b2744e6SAlexei Starovoitov case BPF_H:
7953b2744e6SAlexei Starovoitov /* Emit 'movzx rax, word ptr [rax + off]' */
7963b2744e6SAlexei Starovoitov EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xB7);
7973b2744e6SAlexei Starovoitov break;
7983b2744e6SAlexei Starovoitov case BPF_W:
7993b2744e6SAlexei Starovoitov /* Emit 'mov eax, dword ptr [rax+0x14]' */
8003b2744e6SAlexei Starovoitov if (is_ereg(dst_reg) || is_ereg(src_reg))
8013b2744e6SAlexei Starovoitov EMIT2(add_2mod(0x40, src_reg, dst_reg), 0x8B);
8023b2744e6SAlexei Starovoitov else
8033b2744e6SAlexei Starovoitov EMIT1(0x8B);
8043b2744e6SAlexei Starovoitov break;
8053b2744e6SAlexei Starovoitov case BPF_DW:
8063b2744e6SAlexei Starovoitov /* Emit 'mov rax, qword ptr [rax+0x14]' */
8073b2744e6SAlexei Starovoitov EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x8B);
8083b2744e6SAlexei Starovoitov break;
8093b2744e6SAlexei Starovoitov }
81011c11d07SBrendan Jackman emit_insn_suffix(&prog, src_reg, dst_reg, off);
8113b2744e6SAlexei Starovoitov *pprog = prog;
8123b2744e6SAlexei Starovoitov }
8133b2744e6SAlexei Starovoitov
8141f9a1ea8SYonghong Song /* LDSX: dst_reg = *(s8*)(src_reg + off) */
emit_ldsx(u8 ** pprog,u32 size,u32 dst_reg,u32 src_reg,int off)8151f9a1ea8SYonghong Song static void emit_ldsx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
8161f9a1ea8SYonghong Song {
8171f9a1ea8SYonghong Song u8 *prog = *pprog;
8181f9a1ea8SYonghong Song
8191f9a1ea8SYonghong Song switch (size) {
8201f9a1ea8SYonghong Song case BPF_B:
8211f9a1ea8SYonghong Song /* Emit 'movsx rax, byte ptr [rax + off]' */
8221f9a1ea8SYonghong Song EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xBE);
8231f9a1ea8SYonghong Song break;
8241f9a1ea8SYonghong Song case BPF_H:
8251f9a1ea8SYonghong Song /* Emit 'movsx rax, word ptr [rax + off]' */
8261f9a1ea8SYonghong Song EMIT3(add_2mod(0x48, src_reg, dst_reg), 0x0F, 0xBF);
8271f9a1ea8SYonghong Song break;
8281f9a1ea8SYonghong Song case BPF_W:
8291f9a1ea8SYonghong Song /* Emit 'movsx rax, dword ptr [rax+0x14]' */
8301f9a1ea8SYonghong Song EMIT2(add_2mod(0x48, src_reg, dst_reg), 0x63);
8311f9a1ea8SYonghong Song break;
8321f9a1ea8SYonghong Song }
8331f9a1ea8SYonghong Song emit_insn_suffix(&prog, src_reg, dst_reg, off);
8341f9a1ea8SYonghong Song *pprog = prog;
8351f9a1ea8SYonghong Song }
8361f9a1ea8SYonghong Song
8373b2744e6SAlexei Starovoitov /* STX: *(u8*)(dst_reg + off) = src_reg */
emit_stx(u8 ** pprog,u32 size,u32 dst_reg,u32 src_reg,int off)8383b2744e6SAlexei Starovoitov static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off)
8393b2744e6SAlexei Starovoitov {
8403b2744e6SAlexei Starovoitov u8 *prog = *pprog;
8413b2744e6SAlexei Starovoitov
8423b2744e6SAlexei Starovoitov switch (size) {
8433b2744e6SAlexei Starovoitov case BPF_B:
8443b2744e6SAlexei Starovoitov /* Emit 'mov byte ptr [rax + off], al' */
845aee194b1SLuke Nelson if (is_ereg(dst_reg) || is_ereg_8l(src_reg))
846aee194b1SLuke Nelson /* Add extra byte for eregs or SIL,DIL,BPL in src_reg */
8473b2744e6SAlexei Starovoitov EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88);
8483b2744e6SAlexei Starovoitov else
8493b2744e6SAlexei Starovoitov EMIT1(0x88);
8503b2744e6SAlexei Starovoitov break;
8513b2744e6SAlexei Starovoitov case BPF_H:
8523b2744e6SAlexei Starovoitov if (is_ereg(dst_reg) || is_ereg(src_reg))
8533b2744e6SAlexei Starovoitov EMIT3(0x66, add_2mod(0x40, dst_reg, src_reg), 0x89);
8543b2744e6SAlexei Starovoitov else
8553b2744e6SAlexei Starovoitov EMIT2(0x66, 0x89);
8563b2744e6SAlexei Starovoitov break;
8573b2744e6SAlexei Starovoitov case BPF_W:
8583b2744e6SAlexei Starovoitov if (is_ereg(dst_reg) || is_ereg(src_reg))
8593b2744e6SAlexei Starovoitov EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x89);
8603b2744e6SAlexei Starovoitov else
8613b2744e6SAlexei Starovoitov EMIT1(0x89);
8623b2744e6SAlexei Starovoitov break;
8633b2744e6SAlexei Starovoitov case BPF_DW:
8643b2744e6SAlexei Starovoitov EMIT2(add_2mod(0x48, dst_reg, src_reg), 0x89);
8653b2744e6SAlexei Starovoitov break;
8663b2744e6SAlexei Starovoitov }
86711c11d07SBrendan Jackman emit_insn_suffix(&prog, dst_reg, src_reg, off);
8683b2744e6SAlexei Starovoitov *pprog = prog;
8693b2744e6SAlexei Starovoitov }
8703b2744e6SAlexei Starovoitov
emit_atomic(u8 ** pprog,u8 atomic_op,u32 dst_reg,u32 src_reg,s16 off,u8 bpf_size)87191c960b0SBrendan Jackman static int emit_atomic(u8 **pprog, u8 atomic_op,
87291c960b0SBrendan Jackman u32 dst_reg, u32 src_reg, s16 off, u8 bpf_size)
87391c960b0SBrendan Jackman {
87491c960b0SBrendan Jackman u8 *prog = *pprog;
87591c960b0SBrendan Jackman
87691c960b0SBrendan Jackman EMIT1(0xF0); /* lock prefix */
87791c960b0SBrendan Jackman
87891c960b0SBrendan Jackman maybe_emit_mod(&prog, dst_reg, src_reg, bpf_size == BPF_DW);
87991c960b0SBrendan Jackman
88091c960b0SBrendan Jackman /* emit opcode */
88191c960b0SBrendan Jackman switch (atomic_op) {
88291c960b0SBrendan Jackman case BPF_ADD:
883981f94c3SBrendan Jackman case BPF_AND:
884981f94c3SBrendan Jackman case BPF_OR:
885981f94c3SBrendan Jackman case BPF_XOR:
88691c960b0SBrendan Jackman /* lock *(u32/u64*)(dst_reg + off) <op>= src_reg */
88791c960b0SBrendan Jackman EMIT1(simple_alu_opcodes[atomic_op]);
88891c960b0SBrendan Jackman break;
8895ca419f2SBrendan Jackman case BPF_ADD | BPF_FETCH:
8905ca419f2SBrendan Jackman /* src_reg = atomic_fetch_add(dst_reg + off, src_reg); */
8915ca419f2SBrendan Jackman EMIT2(0x0F, 0xC1);
8925ca419f2SBrendan Jackman break;
8935ffa2550SBrendan Jackman case BPF_XCHG:
8945ffa2550SBrendan Jackman /* src_reg = atomic_xchg(dst_reg + off, src_reg); */
8955ffa2550SBrendan Jackman EMIT1(0x87);
8965ffa2550SBrendan Jackman break;
8975ffa2550SBrendan Jackman case BPF_CMPXCHG:
8985ffa2550SBrendan Jackman /* r0 = atomic_cmpxchg(dst_reg + off, r0, src_reg); */
8995ffa2550SBrendan Jackman EMIT2(0x0F, 0xB1);
9005ffa2550SBrendan Jackman break;
90191c960b0SBrendan Jackman default:
90291c960b0SBrendan Jackman pr_err("bpf_jit: unknown atomic opcode %02x\n", atomic_op);
90391c960b0SBrendan Jackman return -EFAULT;
90491c960b0SBrendan Jackman }
90591c960b0SBrendan Jackman
90691c960b0SBrendan Jackman emit_insn_suffix(&prog, dst_reg, src_reg, off);
90791c960b0SBrendan Jackman
90891c960b0SBrendan Jackman *pprog = prog;
90991c960b0SBrendan Jackman return 0;
91091c960b0SBrendan Jackman }
91191c960b0SBrendan Jackman
ex_handler_bpf(const struct exception_table_entry * x,struct pt_regs * regs)91246d28947SThomas Gleixner bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs)
9133dec541bSAlexei Starovoitov {
9143dec541bSAlexei Starovoitov u32 reg = x->fixup >> 8;
9153dec541bSAlexei Starovoitov
9163dec541bSAlexei Starovoitov /* jump over faulting load and clear dest register */
9173dec541bSAlexei Starovoitov *(unsigned long *)((void *)regs + reg) = 0;
9183dec541bSAlexei Starovoitov regs->ip += x->fixup & 0xff;
9193dec541bSAlexei Starovoitov return true;
9203dec541bSAlexei Starovoitov }
9213dec541bSAlexei Starovoitov
detect_reg_usage(struct bpf_insn * insn,int insn_cnt,bool * regs_used,bool * tail_call_seen)922ebf7d1f5SMaciej Fijalkowski static void detect_reg_usage(struct bpf_insn *insn, int insn_cnt,
923ebf7d1f5SMaciej Fijalkowski bool *regs_used, bool *tail_call_seen)
924ebf7d1f5SMaciej Fijalkowski {
925ebf7d1f5SMaciej Fijalkowski int i;
926ebf7d1f5SMaciej Fijalkowski
927ebf7d1f5SMaciej Fijalkowski for (i = 1; i <= insn_cnt; i++, insn++) {
928ebf7d1f5SMaciej Fijalkowski if (insn->code == (BPF_JMP | BPF_TAIL_CALL))
929ebf7d1f5SMaciej Fijalkowski *tail_call_seen = true;
930ebf7d1f5SMaciej Fijalkowski if (insn->dst_reg == BPF_REG_6 || insn->src_reg == BPF_REG_6)
931ebf7d1f5SMaciej Fijalkowski regs_used[0] = true;
932ebf7d1f5SMaciej Fijalkowski if (insn->dst_reg == BPF_REG_7 || insn->src_reg == BPF_REG_7)
933ebf7d1f5SMaciej Fijalkowski regs_used[1] = true;
934ebf7d1f5SMaciej Fijalkowski if (insn->dst_reg == BPF_REG_8 || insn->src_reg == BPF_REG_8)
935ebf7d1f5SMaciej Fijalkowski regs_used[2] = true;
936ebf7d1f5SMaciej Fijalkowski if (insn->dst_reg == BPF_REG_9 || insn->src_reg == BPF_REG_9)
937ebf7d1f5SMaciej Fijalkowski regs_used[3] = true;
938ebf7d1f5SMaciej Fijalkowski }
939ebf7d1f5SMaciej Fijalkowski }
940ebf7d1f5SMaciej Fijalkowski
emit_nops(u8 ** pprog,int len)941ced50fc4SJiri Olsa static void emit_nops(u8 **pprog, int len)
94293c5aeccSGary Lin {
94393c5aeccSGary Lin u8 *prog = *pprog;
944ced50fc4SJiri Olsa int i, noplen;
94593c5aeccSGary Lin
94693c5aeccSGary Lin while (len > 0) {
94793c5aeccSGary Lin noplen = len;
94893c5aeccSGary Lin
94993c5aeccSGary Lin if (noplen > ASM_NOP_MAX)
95093c5aeccSGary Lin noplen = ASM_NOP_MAX;
95193c5aeccSGary Lin
95293c5aeccSGary Lin for (i = 0; i < noplen; i++)
953a89dfde3SPeter Zijlstra EMIT1(x86_nops[noplen][i]);
95493c5aeccSGary Lin len -= noplen;
95593c5aeccSGary Lin }
95693c5aeccSGary Lin
95793c5aeccSGary Lin *pprog = prog;
95893c5aeccSGary Lin }
95993c5aeccSGary Lin
96077d8f5d4SJie Meng /* emit the 3-byte VEX prefix
96177d8f5d4SJie Meng *
96277d8f5d4SJie Meng * r: same as rex.r, extra bit for ModRM reg field
96377d8f5d4SJie Meng * x: same as rex.x, extra bit for SIB index field
96477d8f5d4SJie Meng * b: same as rex.b, extra bit for ModRM r/m, or SIB base
96577d8f5d4SJie Meng * m: opcode map select, encoding escape bytes e.g. 0x0f38
96677d8f5d4SJie Meng * w: same as rex.w (32 bit or 64 bit) or opcode specific
96777d8f5d4SJie Meng * src_reg2: additional source reg (encoded as BPF reg)
96877d8f5d4SJie Meng * l: vector length (128 bit or 256 bit) or reserved
96977d8f5d4SJie Meng * pp: opcode prefix (none, 0x66, 0xf2 or 0xf3)
97077d8f5d4SJie Meng */
emit_3vex(u8 ** pprog,bool r,bool x,bool b,u8 m,bool w,u8 src_reg2,bool l,u8 pp)97177d8f5d4SJie Meng static void emit_3vex(u8 **pprog, bool r, bool x, bool b, u8 m,
97277d8f5d4SJie Meng bool w, u8 src_reg2, bool l, u8 pp)
97377d8f5d4SJie Meng {
97477d8f5d4SJie Meng u8 *prog = *pprog;
97577d8f5d4SJie Meng const u8 b0 = 0xc4; /* first byte of 3-byte VEX prefix */
97677d8f5d4SJie Meng u8 b1, b2;
97777d8f5d4SJie Meng u8 vvvv = reg2hex[src_reg2];
97877d8f5d4SJie Meng
97977d8f5d4SJie Meng /* reg2hex gives only the lower 3 bit of vvvv */
98077d8f5d4SJie Meng if (is_ereg(src_reg2))
98177d8f5d4SJie Meng vvvv |= 1 << 3;
98277d8f5d4SJie Meng
98377d8f5d4SJie Meng /*
98477d8f5d4SJie Meng * 2nd byte of 3-byte VEX prefix
98577d8f5d4SJie Meng * ~ means bit inverted encoding
98677d8f5d4SJie Meng *
98777d8f5d4SJie Meng * 7 0
98877d8f5d4SJie Meng * +---+---+---+---+---+---+---+---+
98977d8f5d4SJie Meng * |~R |~X |~B | m |
99077d8f5d4SJie Meng * +---+---+---+---+---+---+---+---+
99177d8f5d4SJie Meng */
99277d8f5d4SJie Meng b1 = (!r << 7) | (!x << 6) | (!b << 5) | (m & 0x1f);
99377d8f5d4SJie Meng /*
99477d8f5d4SJie Meng * 3rd byte of 3-byte VEX prefix
99577d8f5d4SJie Meng *
99677d8f5d4SJie Meng * 7 0
99777d8f5d4SJie Meng * +---+---+---+---+---+---+---+---+
99877d8f5d4SJie Meng * | W | ~vvvv | L | pp |
99977d8f5d4SJie Meng * +---+---+---+---+---+---+---+---+
100077d8f5d4SJie Meng */
100177d8f5d4SJie Meng b2 = (w << 7) | ((~vvvv & 0xf) << 3) | (l << 2) | (pp & 3);
100277d8f5d4SJie Meng
100377d8f5d4SJie Meng EMIT3(b0, b1, b2);
100477d8f5d4SJie Meng *pprog = prog;
100577d8f5d4SJie Meng }
100677d8f5d4SJie Meng
100777d8f5d4SJie Meng /* emit BMI2 shift instruction */
emit_shiftx(u8 ** pprog,u32 dst_reg,u8 src_reg,bool is64,u8 op)100877d8f5d4SJie Meng static void emit_shiftx(u8 **pprog, u32 dst_reg, u8 src_reg, bool is64, u8 op)
100977d8f5d4SJie Meng {
101077d8f5d4SJie Meng u8 *prog = *pprog;
101177d8f5d4SJie Meng bool r = is_ereg(dst_reg);
101277d8f5d4SJie Meng u8 m = 2; /* escape code 0f38 */
101377d8f5d4SJie Meng
101477d8f5d4SJie Meng emit_3vex(&prog, r, false, r, m, is64, src_reg, false, op);
101577d8f5d4SJie Meng EMIT2(0xf7, add_2reg(0xC0, dst_reg, dst_reg));
101677d8f5d4SJie Meng *pprog = prog;
101777d8f5d4SJie Meng }
101877d8f5d4SJie Meng
101993c5aeccSGary Lin #define INSN_SZ_DIFF (((addrs[i] - addrs[i - 1]) - (prog - temp)))
102093c5aeccSGary Lin
10218f873cc3SLeon Hwang /* mov rax, qword ptr [rbp - rounded_stack_depth - 8] */
10228f873cc3SLeon Hwang #define RESTORE_TAIL_CALL_CNT(stack) \
10238f873cc3SLeon Hwang EMIT3_off32(0x48, 0x8B, 0x85, -round_up(stack, 8) - 8)
10248f873cc3SLeon Hwang
do_jit(struct bpf_prog * bpf_prog,int * addrs,u8 * image,u8 * rw_image,int oldproglen,struct jit_context * ctx,bool jmp_padding)10251022a549SSong Liu static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, u8 *rw_image,
102693c5aeccSGary Lin int oldproglen, struct jit_context *ctx, bool jmp_padding)
1027b52f00e6SAlexei Starovoitov {
1028ebf7d1f5SMaciej Fijalkowski bool tail_call_reachable = bpf_prog->aux->tail_call_reachable;
1029b52f00e6SAlexei Starovoitov struct bpf_insn *insn = bpf_prog->insnsi;
1030ebf7d1f5SMaciej Fijalkowski bool callee_regs_used[4] = {};
1031b52f00e6SAlexei Starovoitov int insn_cnt = bpf_prog->len;
1032ebf7d1f5SMaciej Fijalkowski bool tail_call_seen = false;
1033b52f00e6SAlexei Starovoitov bool seen_exit = false;
1034b52f00e6SAlexei Starovoitov u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY];
1035ced50fc4SJiri Olsa int i, excnt = 0;
103693c5aeccSGary Lin int ilen, proglen = 0;
1037b52f00e6SAlexei Starovoitov u8 *prog = temp;
103891c960b0SBrendan Jackman int err;
1039b52f00e6SAlexei Starovoitov
1040ebf7d1f5SMaciej Fijalkowski detect_reg_usage(insn, insn_cnt, callee_regs_used,
1041ebf7d1f5SMaciej Fijalkowski &tail_call_seen);
1042ebf7d1f5SMaciej Fijalkowski
1043ebf7d1f5SMaciej Fijalkowski /* tail call's presence in current prog implies it is reachable */
1044ebf7d1f5SMaciej Fijalkowski tail_call_reachable |= tail_call_seen;
1045ebf7d1f5SMaciej Fijalkowski
104608691752SDaniel Borkmann emit_prologue(&prog, bpf_prog->aux->stack_depth,
1047ebf7d1f5SMaciej Fijalkowski bpf_prog_was_classic(bpf_prog), tail_call_reachable,
1048ebf7d1f5SMaciej Fijalkowski bpf_prog->aux->func_idx != 0);
1049ebf7d1f5SMaciej Fijalkowski push_callee_regs(&prog, callee_regs_used);
105093c5aeccSGary Lin
105193c5aeccSGary Lin ilen = prog - temp;
10521022a549SSong Liu if (rw_image)
10531022a549SSong Liu memcpy(rw_image + proglen, temp, ilen);
105493c5aeccSGary Lin proglen += ilen;
105593c5aeccSGary Lin addrs[0] = proglen;
105693c5aeccSGary Lin prog = temp;
1057b52f00e6SAlexei Starovoitov
10587c2e988fSAlexei Starovoitov for (i = 1; i <= insn_cnt; i++, insn++) {
1059e430f34eSAlexei Starovoitov const s32 imm32 = insn->imm;
1060e430f34eSAlexei Starovoitov u32 dst_reg = insn->dst_reg;
1061e430f34eSAlexei Starovoitov u32 src_reg = insn->src_reg;
10626fe8b9c1SDaniel Borkmann u8 b2 = 0, b3 = 0;
10634c5de127SAlexei Starovoitov u8 *start_of_ldx;
106462258278SAlexei Starovoitov s64 jmp_offset;
106590156f4bSDave Marchevsky s16 insn_off;
106662258278SAlexei Starovoitov u8 jmp_cond;
106762258278SAlexei Starovoitov u8 *func;
106893c5aeccSGary Lin int nops;
106962258278SAlexei Starovoitov
107062258278SAlexei Starovoitov switch (insn->code) {
107162258278SAlexei Starovoitov /* ALU */
107262258278SAlexei Starovoitov case BPF_ALU | BPF_ADD | BPF_X:
107362258278SAlexei Starovoitov case BPF_ALU | BPF_SUB | BPF_X:
107462258278SAlexei Starovoitov case BPF_ALU | BPF_AND | BPF_X:
107562258278SAlexei Starovoitov case BPF_ALU | BPF_OR | BPF_X:
107662258278SAlexei Starovoitov case BPF_ALU | BPF_XOR | BPF_X:
107762258278SAlexei Starovoitov case BPF_ALU64 | BPF_ADD | BPF_X:
107862258278SAlexei Starovoitov case BPF_ALU64 | BPF_SUB | BPF_X:
107962258278SAlexei Starovoitov case BPF_ALU64 | BPF_AND | BPF_X:
108062258278SAlexei Starovoitov case BPF_ALU64 | BPF_OR | BPF_X:
108162258278SAlexei Starovoitov case BPF_ALU64 | BPF_XOR | BPF_X:
108274007cfcSBrendan Jackman maybe_emit_mod(&prog, dst_reg, src_reg,
108374007cfcSBrendan Jackman BPF_CLASS(insn->code) == BPF_ALU64);
1084e5f02cacSBrendan Jackman b2 = simple_alu_opcodes[BPF_OP(insn->code)];
1085e430f34eSAlexei Starovoitov EMIT2(b2, add_2reg(0xC0, dst_reg, src_reg));
10860a14842fSEric Dumazet break;
108762258278SAlexei Starovoitov
108862258278SAlexei Starovoitov case BPF_ALU64 | BPF_MOV | BPF_X:
108962258278SAlexei Starovoitov case BPF_ALU | BPF_MOV | BPF_X:
10908100928cSYonghong Song if (insn->off == 0)
10914c38e2f3SDaniel Borkmann emit_mov_reg(&prog,
10924c38e2f3SDaniel Borkmann BPF_CLASS(insn->code) == BPF_ALU64,
10934c38e2f3SDaniel Borkmann dst_reg, src_reg);
10948100928cSYonghong Song else
10958100928cSYonghong Song emit_movsx_reg(&prog, insn->off,
10968100928cSYonghong Song BPF_CLASS(insn->code) == BPF_ALU64,
10978100928cSYonghong Song dst_reg, src_reg);
109862258278SAlexei Starovoitov break;
109962258278SAlexei Starovoitov
1100e430f34eSAlexei Starovoitov /* neg dst */
110162258278SAlexei Starovoitov case BPF_ALU | BPF_NEG:
110262258278SAlexei Starovoitov case BPF_ALU64 | BPF_NEG:
11036364d7d7SJie Meng maybe_emit_1mod(&prog, dst_reg,
11046364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_ALU64);
1105e430f34eSAlexei Starovoitov EMIT2(0xF7, add_1reg(0xD8, dst_reg));
110662258278SAlexei Starovoitov break;
110762258278SAlexei Starovoitov
110862258278SAlexei Starovoitov case BPF_ALU | BPF_ADD | BPF_K:
110962258278SAlexei Starovoitov case BPF_ALU | BPF_SUB | BPF_K:
111062258278SAlexei Starovoitov case BPF_ALU | BPF_AND | BPF_K:
111162258278SAlexei Starovoitov case BPF_ALU | BPF_OR | BPF_K:
111262258278SAlexei Starovoitov case BPF_ALU | BPF_XOR | BPF_K:
111362258278SAlexei Starovoitov case BPF_ALU64 | BPF_ADD | BPF_K:
111462258278SAlexei Starovoitov case BPF_ALU64 | BPF_SUB | BPF_K:
111562258278SAlexei Starovoitov case BPF_ALU64 | BPF_AND | BPF_K:
111662258278SAlexei Starovoitov case BPF_ALU64 | BPF_OR | BPF_K:
111762258278SAlexei Starovoitov case BPF_ALU64 | BPF_XOR | BPF_K:
11186364d7d7SJie Meng maybe_emit_1mod(&prog, dst_reg,
11196364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_ALU64);
112062258278SAlexei Starovoitov
1121a2c7a983SIngo Molnar /*
1122a2c7a983SIngo Molnar * b3 holds 'normal' opcode, b2 short form only valid
1123de0a444dSDaniel Borkmann * in case dst is eax/rax.
1124de0a444dSDaniel Borkmann */
112562258278SAlexei Starovoitov switch (BPF_OP(insn->code)) {
1126de0a444dSDaniel Borkmann case BPF_ADD:
1127de0a444dSDaniel Borkmann b3 = 0xC0;
1128de0a444dSDaniel Borkmann b2 = 0x05;
1129de0a444dSDaniel Borkmann break;
1130de0a444dSDaniel Borkmann case BPF_SUB:
1131de0a444dSDaniel Borkmann b3 = 0xE8;
1132de0a444dSDaniel Borkmann b2 = 0x2D;
1133de0a444dSDaniel Borkmann break;
1134de0a444dSDaniel Borkmann case BPF_AND:
1135de0a444dSDaniel Borkmann b3 = 0xE0;
1136de0a444dSDaniel Borkmann b2 = 0x25;
1137de0a444dSDaniel Borkmann break;
1138de0a444dSDaniel Borkmann case BPF_OR:
1139de0a444dSDaniel Borkmann b3 = 0xC8;
1140de0a444dSDaniel Borkmann b2 = 0x0D;
1141de0a444dSDaniel Borkmann break;
1142de0a444dSDaniel Borkmann case BPF_XOR:
1143de0a444dSDaniel Borkmann b3 = 0xF0;
1144de0a444dSDaniel Borkmann b2 = 0x35;
1145de0a444dSDaniel Borkmann break;
114662258278SAlexei Starovoitov }
114762258278SAlexei Starovoitov
1148e430f34eSAlexei Starovoitov if (is_imm8(imm32))
1149e430f34eSAlexei Starovoitov EMIT3(0x83, add_1reg(b3, dst_reg), imm32);
1150de0a444dSDaniel Borkmann else if (is_axreg(dst_reg))
1151de0a444dSDaniel Borkmann EMIT1_off32(b2, imm32);
115262258278SAlexei Starovoitov else
1153e430f34eSAlexei Starovoitov EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32);
115462258278SAlexei Starovoitov break;
115562258278SAlexei Starovoitov
115662258278SAlexei Starovoitov case BPF_ALU64 | BPF_MOV | BPF_K:
115762258278SAlexei Starovoitov case BPF_ALU | BPF_MOV | BPF_K:
11586fe8b9c1SDaniel Borkmann emit_mov_imm32(&prog, BPF_CLASS(insn->code) == BPF_ALU64,
11596fe8b9c1SDaniel Borkmann dst_reg, imm32);
116062258278SAlexei Starovoitov break;
116162258278SAlexei Starovoitov
116202ab695bSAlexei Starovoitov case BPF_LD | BPF_IMM | BPF_DW:
11636fe8b9c1SDaniel Borkmann emit_mov_imm64(&prog, dst_reg, insn[1].imm, insn[0].imm);
116402ab695bSAlexei Starovoitov insn++;
116502ab695bSAlexei Starovoitov i++;
116602ab695bSAlexei Starovoitov break;
116702ab695bSAlexei Starovoitov
1168e430f34eSAlexei Starovoitov /* dst %= src, dst /= src, dst %= imm32, dst /= imm32 */
116962258278SAlexei Starovoitov case BPF_ALU | BPF_MOD | BPF_X:
117062258278SAlexei Starovoitov case BPF_ALU | BPF_DIV | BPF_X:
117162258278SAlexei Starovoitov case BPF_ALU | BPF_MOD | BPF_K:
117262258278SAlexei Starovoitov case BPF_ALU | BPF_DIV | BPF_K:
117362258278SAlexei Starovoitov case BPF_ALU64 | BPF_MOD | BPF_X:
117462258278SAlexei Starovoitov case BPF_ALU64 | BPF_DIV | BPF_X:
117562258278SAlexei Starovoitov case BPF_ALU64 | BPF_MOD | BPF_K:
117657a610f1SJie Meng case BPF_ALU64 | BPF_DIV | BPF_K: {
11774c38e2f3SDaniel Borkmann bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
11784c38e2f3SDaniel Borkmann
1179d806a0cfSDaniel Borkmann if (dst_reg != BPF_REG_0)
118062258278SAlexei Starovoitov EMIT1(0x50); /* push rax */
1181d806a0cfSDaniel Borkmann if (dst_reg != BPF_REG_3)
118262258278SAlexei Starovoitov EMIT1(0x52); /* push rdx */
118362258278SAlexei Starovoitov
118457a610f1SJie Meng if (BPF_SRC(insn->code) == BPF_X) {
118557a610f1SJie Meng if (src_reg == BPF_REG_0 ||
118657a610f1SJie Meng src_reg == BPF_REG_3) {
118762258278SAlexei Starovoitov /* mov r11, src_reg */
118862258278SAlexei Starovoitov EMIT_mov(AUX_REG, src_reg);
118957a610f1SJie Meng src_reg = AUX_REG;
119057a610f1SJie Meng }
119157a610f1SJie Meng } else {
119262258278SAlexei Starovoitov /* mov r11, imm32 */
119362258278SAlexei Starovoitov EMIT3_off32(0x49, 0xC7, 0xC3, imm32);
119457a610f1SJie Meng src_reg = AUX_REG;
119557a610f1SJie Meng }
119662258278SAlexei Starovoitov
119757a610f1SJie Meng if (dst_reg != BPF_REG_0)
119862258278SAlexei Starovoitov /* mov rax, dst_reg */
119957a610f1SJie Meng emit_mov_reg(&prog, is64, BPF_REG_0, dst_reg);
120062258278SAlexei Starovoitov
1201ec0e2da9SYonghong Song if (insn->off == 0) {
120262258278SAlexei Starovoitov /*
120362258278SAlexei Starovoitov * xor edx, edx
120462258278SAlexei Starovoitov * equivalent to 'xor rdx, rdx', but one byte less
120562258278SAlexei Starovoitov */
120662258278SAlexei Starovoitov EMIT2(0x31, 0xd2);
120762258278SAlexei Starovoitov
120857a610f1SJie Meng /* div src_reg */
12096364d7d7SJie Meng maybe_emit_1mod(&prog, src_reg, is64);
121057a610f1SJie Meng EMIT2(0xF7, add_1reg(0xF0, src_reg));
1211ec0e2da9SYonghong Song } else {
1212ec0e2da9SYonghong Song if (BPF_CLASS(insn->code) == BPF_ALU)
1213ec0e2da9SYonghong Song EMIT1(0x99); /* cdq */
1214ec0e2da9SYonghong Song else
1215ec0e2da9SYonghong Song EMIT2(0x48, 0x99); /* cqo */
1216ec0e2da9SYonghong Song
1217ec0e2da9SYonghong Song /* idiv src_reg */
1218ec0e2da9SYonghong Song maybe_emit_1mod(&prog, src_reg, is64);
1219ec0e2da9SYonghong Song EMIT2(0xF7, add_1reg(0xF8, src_reg));
1220ec0e2da9SYonghong Song }
122162258278SAlexei Starovoitov
122257a610f1SJie Meng if (BPF_OP(insn->code) == BPF_MOD &&
122357a610f1SJie Meng dst_reg != BPF_REG_3)
122457a610f1SJie Meng /* mov dst_reg, rdx */
122557a610f1SJie Meng emit_mov_reg(&prog, is64, dst_reg, BPF_REG_3);
122657a610f1SJie Meng else if (BPF_OP(insn->code) == BPF_DIV &&
122757a610f1SJie Meng dst_reg != BPF_REG_0)
122857a610f1SJie Meng /* mov dst_reg, rax */
122957a610f1SJie Meng emit_mov_reg(&prog, is64, dst_reg, BPF_REG_0);
123062258278SAlexei Starovoitov
1231d806a0cfSDaniel Borkmann if (dst_reg != BPF_REG_3)
123262258278SAlexei Starovoitov EMIT1(0x5A); /* pop rdx */
123357a610f1SJie Meng if (dst_reg != BPF_REG_0)
123462258278SAlexei Starovoitov EMIT1(0x58); /* pop rax */
123562258278SAlexei Starovoitov break;
12364c38e2f3SDaniel Borkmann }
123762258278SAlexei Starovoitov
123862258278SAlexei Starovoitov case BPF_ALU | BPF_MUL | BPF_K:
123962258278SAlexei Starovoitov case BPF_ALU64 | BPF_MUL | BPF_K:
12406364d7d7SJie Meng maybe_emit_mod(&prog, dst_reg, dst_reg,
12416364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_ALU64);
124262258278SAlexei Starovoitov
1243c0354077SJie Meng if (is_imm8(imm32))
1244c0354077SJie Meng /* imul dst_reg, dst_reg, imm8 */
1245c0354077SJie Meng EMIT3(0x6B, add_2reg(0xC0, dst_reg, dst_reg),
1246c0354077SJie Meng imm32);
124762258278SAlexei Starovoitov else
1248c0354077SJie Meng /* imul dst_reg, dst_reg, imm32 */
1249c0354077SJie Meng EMIT2_off32(0x69,
1250c0354077SJie Meng add_2reg(0xC0, dst_reg, dst_reg),
1251c0354077SJie Meng imm32);
125262258278SAlexei Starovoitov break;
1253c0354077SJie Meng
1254c0354077SJie Meng case BPF_ALU | BPF_MUL | BPF_X:
1255c0354077SJie Meng case BPF_ALU64 | BPF_MUL | BPF_X:
12566364d7d7SJie Meng maybe_emit_mod(&prog, src_reg, dst_reg,
12576364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_ALU64);
1258c0354077SJie Meng
1259c0354077SJie Meng /* imul dst_reg, src_reg */
1260c0354077SJie Meng EMIT3(0x0F, 0xAF, add_2reg(0xC0, src_reg, dst_reg));
1261c0354077SJie Meng break;
1262c0354077SJie Meng
1263a2c7a983SIngo Molnar /* Shifts */
126462258278SAlexei Starovoitov case BPF_ALU | BPF_LSH | BPF_K:
126562258278SAlexei Starovoitov case BPF_ALU | BPF_RSH | BPF_K:
126662258278SAlexei Starovoitov case BPF_ALU | BPF_ARSH | BPF_K:
126762258278SAlexei Starovoitov case BPF_ALU64 | BPF_LSH | BPF_K:
126862258278SAlexei Starovoitov case BPF_ALU64 | BPF_RSH | BPF_K:
126962258278SAlexei Starovoitov case BPF_ALU64 | BPF_ARSH | BPF_K:
12706364d7d7SJie Meng maybe_emit_1mod(&prog, dst_reg,
12716364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_ALU64);
127262258278SAlexei Starovoitov
1273e5f02cacSBrendan Jackman b3 = simple_alu_opcodes[BPF_OP(insn->code)];
127488e69a1fSDaniel Borkmann if (imm32 == 1)
127588e69a1fSDaniel Borkmann EMIT2(0xD1, add_1reg(b3, dst_reg));
127688e69a1fSDaniel Borkmann else
1277e430f34eSAlexei Starovoitov EMIT3(0xC1, add_1reg(b3, dst_reg), imm32);
127862258278SAlexei Starovoitov break;
127962258278SAlexei Starovoitov
128072b603eeSAlexei Starovoitov case BPF_ALU | BPF_LSH | BPF_X:
128172b603eeSAlexei Starovoitov case BPF_ALU | BPF_RSH | BPF_X:
128272b603eeSAlexei Starovoitov case BPF_ALU | BPF_ARSH | BPF_X:
128372b603eeSAlexei Starovoitov case BPF_ALU64 | BPF_LSH | BPF_X:
128472b603eeSAlexei Starovoitov case BPF_ALU64 | BPF_RSH | BPF_X:
128572b603eeSAlexei Starovoitov case BPF_ALU64 | BPF_ARSH | BPF_X:
128677d8f5d4SJie Meng /* BMI2 shifts aren't better when shift count is already in rcx */
128777d8f5d4SJie Meng if (boot_cpu_has(X86_FEATURE_BMI2) && src_reg != BPF_REG_4) {
128877d8f5d4SJie Meng /* shrx/sarx/shlx dst_reg, dst_reg, src_reg */
128977d8f5d4SJie Meng bool w = (BPF_CLASS(insn->code) == BPF_ALU64);
129077d8f5d4SJie Meng u8 op;
129172b603eeSAlexei Starovoitov
129277d8f5d4SJie Meng switch (BPF_OP(insn->code)) {
129377d8f5d4SJie Meng case BPF_LSH:
129477d8f5d4SJie Meng op = 1; /* prefix 0x66 */
129577d8f5d4SJie Meng break;
129677d8f5d4SJie Meng case BPF_RSH:
129777d8f5d4SJie Meng op = 3; /* prefix 0xf2 */
129877d8f5d4SJie Meng break;
129977d8f5d4SJie Meng case BPF_ARSH:
130077d8f5d4SJie Meng op = 2; /* prefix 0xf3 */
130177d8f5d4SJie Meng break;
130277d8f5d4SJie Meng }
130377d8f5d4SJie Meng
130477d8f5d4SJie Meng emit_shiftx(&prog, dst_reg, src_reg, w, op);
130577d8f5d4SJie Meng
130677d8f5d4SJie Meng break;
130777d8f5d4SJie Meng }
130872b603eeSAlexei Starovoitov
130981b35e7cSJie Meng if (src_reg != BPF_REG_4) { /* common case */
1310a2c7a983SIngo Molnar /* Check for bad case when dst_reg == rcx */
131172b603eeSAlexei Starovoitov if (dst_reg == BPF_REG_4) {
131272b603eeSAlexei Starovoitov /* mov r11, dst_reg */
131372b603eeSAlexei Starovoitov EMIT_mov(AUX_REG, dst_reg);
131472b603eeSAlexei Starovoitov dst_reg = AUX_REG;
131581b35e7cSJie Meng } else {
131672b603eeSAlexei Starovoitov EMIT1(0x51); /* push rcx */
131781b35e7cSJie Meng }
131872b603eeSAlexei Starovoitov /* mov rcx, src_reg */
131972b603eeSAlexei Starovoitov EMIT_mov(BPF_REG_4, src_reg);
132072b603eeSAlexei Starovoitov }
132172b603eeSAlexei Starovoitov
132272b603eeSAlexei Starovoitov /* shl %rax, %cl | shr %rax, %cl | sar %rax, %cl */
13236364d7d7SJie Meng maybe_emit_1mod(&prog, dst_reg,
13246364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_ALU64);
132572b603eeSAlexei Starovoitov
1326e5f02cacSBrendan Jackman b3 = simple_alu_opcodes[BPF_OP(insn->code)];
132772b603eeSAlexei Starovoitov EMIT2(0xD3, add_1reg(b3, dst_reg));
132872b603eeSAlexei Starovoitov
132981b35e7cSJie Meng if (src_reg != BPF_REG_4) {
133072b603eeSAlexei Starovoitov if (insn->dst_reg == BPF_REG_4)
133172b603eeSAlexei Starovoitov /* mov dst_reg, r11 */
133272b603eeSAlexei Starovoitov EMIT_mov(insn->dst_reg, AUX_REG);
133381b35e7cSJie Meng else
133481b35e7cSJie Meng EMIT1(0x59); /* pop rcx */
133581b35e7cSJie Meng }
133681b35e7cSJie Meng
133772b603eeSAlexei Starovoitov break;
133872b603eeSAlexei Starovoitov
133962258278SAlexei Starovoitov case BPF_ALU | BPF_END | BPF_FROM_BE:
13400845c3dbSYonghong Song case BPF_ALU64 | BPF_END | BPF_FROM_LE:
1341e430f34eSAlexei Starovoitov switch (imm32) {
134262258278SAlexei Starovoitov case 16:
1343a2c7a983SIngo Molnar /* Emit 'ror %ax, 8' to swap lower 2 bytes */
134462258278SAlexei Starovoitov EMIT1(0x66);
1345e430f34eSAlexei Starovoitov if (is_ereg(dst_reg))
134662258278SAlexei Starovoitov EMIT1(0x41);
1347e430f34eSAlexei Starovoitov EMIT3(0xC1, add_1reg(0xC8, dst_reg), 8);
1348343f845bSAlexei Starovoitov
1349a2c7a983SIngo Molnar /* Emit 'movzwl eax, ax' */
1350343f845bSAlexei Starovoitov if (is_ereg(dst_reg))
1351343f845bSAlexei Starovoitov EMIT3(0x45, 0x0F, 0xB7);
1352343f845bSAlexei Starovoitov else
1353343f845bSAlexei Starovoitov EMIT2(0x0F, 0xB7);
1354343f845bSAlexei Starovoitov EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
135562258278SAlexei Starovoitov break;
135662258278SAlexei Starovoitov case 32:
1357a2c7a983SIngo Molnar /* Emit 'bswap eax' to swap lower 4 bytes */
1358e430f34eSAlexei Starovoitov if (is_ereg(dst_reg))
135962258278SAlexei Starovoitov EMIT2(0x41, 0x0F);
136062258278SAlexei Starovoitov else
136162258278SAlexei Starovoitov EMIT1(0x0F);
1362e430f34eSAlexei Starovoitov EMIT1(add_1reg(0xC8, dst_reg));
136362258278SAlexei Starovoitov break;
136462258278SAlexei Starovoitov case 64:
1365a2c7a983SIngo Molnar /* Emit 'bswap rax' to swap 8 bytes */
1366e430f34eSAlexei Starovoitov EMIT3(add_1mod(0x48, dst_reg), 0x0F,
1367e430f34eSAlexei Starovoitov add_1reg(0xC8, dst_reg));
136862258278SAlexei Starovoitov break;
136962258278SAlexei Starovoitov }
137062258278SAlexei Starovoitov break;
137162258278SAlexei Starovoitov
137262258278SAlexei Starovoitov case BPF_ALU | BPF_END | BPF_FROM_LE:
1373343f845bSAlexei Starovoitov switch (imm32) {
1374343f845bSAlexei Starovoitov case 16:
1375a2c7a983SIngo Molnar /*
1376a2c7a983SIngo Molnar * Emit 'movzwl eax, ax' to zero extend 16-bit
1377343f845bSAlexei Starovoitov * into 64 bit
1378343f845bSAlexei Starovoitov */
1379343f845bSAlexei Starovoitov if (is_ereg(dst_reg))
1380343f845bSAlexei Starovoitov EMIT3(0x45, 0x0F, 0xB7);
1381343f845bSAlexei Starovoitov else
1382343f845bSAlexei Starovoitov EMIT2(0x0F, 0xB7);
1383343f845bSAlexei Starovoitov EMIT1(add_2reg(0xC0, dst_reg, dst_reg));
1384343f845bSAlexei Starovoitov break;
1385343f845bSAlexei Starovoitov case 32:
1386a2c7a983SIngo Molnar /* Emit 'mov eax, eax' to clear upper 32-bits */
1387343f845bSAlexei Starovoitov if (is_ereg(dst_reg))
1388343f845bSAlexei Starovoitov EMIT1(0x45);
1389343f845bSAlexei Starovoitov EMIT2(0x89, add_2reg(0xC0, dst_reg, dst_reg));
1390343f845bSAlexei Starovoitov break;
1391343f845bSAlexei Starovoitov case 64:
1392343f845bSAlexei Starovoitov /* nop */
1393343f845bSAlexei Starovoitov break;
1394343f845bSAlexei Starovoitov }
139562258278SAlexei Starovoitov break;
139662258278SAlexei Starovoitov
1397f5e81d11SDaniel Borkmann /* speculation barrier */
1398f5e81d11SDaniel Borkmann case BPF_ST | BPF_NOSPEC:
139987c87ecdSPeter Zijlstra EMIT_LFENCE();
1400f5e81d11SDaniel Borkmann break;
1401f5e81d11SDaniel Borkmann
1402e430f34eSAlexei Starovoitov /* ST: *(u8*)(dst_reg + off) = imm */
140362258278SAlexei Starovoitov case BPF_ST | BPF_MEM | BPF_B:
1404e430f34eSAlexei Starovoitov if (is_ereg(dst_reg))
140562258278SAlexei Starovoitov EMIT2(0x41, 0xC6);
140662258278SAlexei Starovoitov else
140762258278SAlexei Starovoitov EMIT1(0xC6);
140862258278SAlexei Starovoitov goto st;
140962258278SAlexei Starovoitov case BPF_ST | BPF_MEM | BPF_H:
1410e430f34eSAlexei Starovoitov if (is_ereg(dst_reg))
141162258278SAlexei Starovoitov EMIT3(0x66, 0x41, 0xC7);
141262258278SAlexei Starovoitov else
141362258278SAlexei Starovoitov EMIT2(0x66, 0xC7);
141462258278SAlexei Starovoitov goto st;
141562258278SAlexei Starovoitov case BPF_ST | BPF_MEM | BPF_W:
1416e430f34eSAlexei Starovoitov if (is_ereg(dst_reg))
141762258278SAlexei Starovoitov EMIT2(0x41, 0xC7);
141862258278SAlexei Starovoitov else
141962258278SAlexei Starovoitov EMIT1(0xC7);
142062258278SAlexei Starovoitov goto st;
142162258278SAlexei Starovoitov case BPF_ST | BPF_MEM | BPF_DW:
1422e430f34eSAlexei Starovoitov EMIT2(add_1mod(0x48, dst_reg), 0xC7);
142362258278SAlexei Starovoitov
142462258278SAlexei Starovoitov st: if (is_imm8(insn->off))
1425e430f34eSAlexei Starovoitov EMIT2(add_1reg(0x40, dst_reg), insn->off);
142662258278SAlexei Starovoitov else
1427e430f34eSAlexei Starovoitov EMIT1_off32(add_1reg(0x80, dst_reg), insn->off);
142862258278SAlexei Starovoitov
1429e430f34eSAlexei Starovoitov EMIT(imm32, bpf_size_to_x86_bytes(BPF_SIZE(insn->code)));
143062258278SAlexei Starovoitov break;
143162258278SAlexei Starovoitov
1432e430f34eSAlexei Starovoitov /* STX: *(u8*)(dst_reg + off) = src_reg */
143362258278SAlexei Starovoitov case BPF_STX | BPF_MEM | BPF_B:
143462258278SAlexei Starovoitov case BPF_STX | BPF_MEM | BPF_H:
143562258278SAlexei Starovoitov case BPF_STX | BPF_MEM | BPF_W:
143662258278SAlexei Starovoitov case BPF_STX | BPF_MEM | BPF_DW:
14373b2744e6SAlexei Starovoitov emit_stx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off);
143862258278SAlexei Starovoitov break;
143962258278SAlexei Starovoitov
1440e430f34eSAlexei Starovoitov /* LDX: dst_reg = *(u8*)(src_reg + off) */
144162258278SAlexei Starovoitov case BPF_LDX | BPF_MEM | BPF_B:
14423dec541bSAlexei Starovoitov case BPF_LDX | BPF_PROBE_MEM | BPF_B:
144362258278SAlexei Starovoitov case BPF_LDX | BPF_MEM | BPF_H:
14443dec541bSAlexei Starovoitov case BPF_LDX | BPF_PROBE_MEM | BPF_H:
144562258278SAlexei Starovoitov case BPF_LDX | BPF_MEM | BPF_W:
14463dec541bSAlexei Starovoitov case BPF_LDX | BPF_PROBE_MEM | BPF_W:
144762258278SAlexei Starovoitov case BPF_LDX | BPF_MEM | BPF_DW:
14483dec541bSAlexei Starovoitov case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
14491f9a1ea8SYonghong Song /* LDXS: dst_reg = *(s8*)(src_reg + off) */
14501f9a1ea8SYonghong Song case BPF_LDX | BPF_MEMSX | BPF_B:
14511f9a1ea8SYonghong Song case BPF_LDX | BPF_MEMSX | BPF_H:
14521f9a1ea8SYonghong Song case BPF_LDX | BPF_MEMSX | BPF_W:
14531f9a1ea8SYonghong Song case BPF_LDX | BPF_PROBE_MEMSX | BPF_B:
14541f9a1ea8SYonghong Song case BPF_LDX | BPF_PROBE_MEMSX | BPF_H:
14551f9a1ea8SYonghong Song case BPF_LDX | BPF_PROBE_MEMSX | BPF_W:
145690156f4bSDave Marchevsky insn_off = insn->off;
1457588a25e9SAlexei Starovoitov
14581f9a1ea8SYonghong Song if (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
14591f9a1ea8SYonghong Song BPF_MODE(insn->code) == BPF_PROBE_MEMSX) {
1460588a25e9SAlexei Starovoitov /* Conservatively check that src_reg + insn->off is a kernel address:
1461af8dc212SPuranjay Mohan * src_reg + insn->off > TASK_SIZE_MAX + PAGE_SIZE
1462af8dc212SPuranjay Mohan * and
1463af8dc212SPuranjay Mohan * src_reg + insn->off < VSYSCALL_ADDR
1464588a25e9SAlexei Starovoitov */
1465588a25e9SAlexei Starovoitov
1466af8dc212SPuranjay Mohan u64 limit = TASK_SIZE_MAX + PAGE_SIZE - VSYSCALL_ADDR;
146790156f4bSDave Marchevsky u8 *end_of_jmp;
146890156f4bSDave Marchevsky
1469af8dc212SPuranjay Mohan /* movabsq r10, VSYSCALL_ADDR */
1470af8dc212SPuranjay Mohan emit_mov_imm64(&prog, BPF_REG_AX, (long)VSYSCALL_ADDR >> 32,
1471af8dc212SPuranjay Mohan (u32)(long)VSYSCALL_ADDR);
147290156f4bSDave Marchevsky
1473af8dc212SPuranjay Mohan /* mov src_reg, r11 */
1474af8dc212SPuranjay Mohan EMIT_mov(AUX_REG, src_reg);
147590156f4bSDave Marchevsky
147690156f4bSDave Marchevsky if (insn->off) {
1477af8dc212SPuranjay Mohan /* add r11, insn->off */
1478af8dc212SPuranjay Mohan maybe_emit_1mod(&prog, AUX_REG, true);
1479af8dc212SPuranjay Mohan EMIT2_off32(0x81, add_1reg(0xC0, AUX_REG), insn->off);
148090156f4bSDave Marchevsky }
148190156f4bSDave Marchevsky
1482af8dc212SPuranjay Mohan /* sub r11, r10 */
1483af8dc212SPuranjay Mohan maybe_emit_mod(&prog, AUX_REG, BPF_REG_AX, true);
1484af8dc212SPuranjay Mohan EMIT2(0x29, add_2reg(0xC0, AUX_REG, BPF_REG_AX));
1485588a25e9SAlexei Starovoitov
1486af8dc212SPuranjay Mohan /* movabsq r10, limit */
1487af8dc212SPuranjay Mohan emit_mov_imm64(&prog, BPF_REG_AX, (long)limit >> 32,
1488af8dc212SPuranjay Mohan (u32)(long)limit);
1489af8dc212SPuranjay Mohan
1490af8dc212SPuranjay Mohan /* cmp r10, r11 */
1491af8dc212SPuranjay Mohan maybe_emit_mod(&prog, AUX_REG, BPF_REG_AX, true);
1492af8dc212SPuranjay Mohan EMIT2(0x39, add_2reg(0xC0, AUX_REG, BPF_REG_AX));
1493af8dc212SPuranjay Mohan
1494af8dc212SPuranjay Mohan /* if unsigned '>', goto load */
1495af8dc212SPuranjay Mohan EMIT2(X86_JA, 0);
149690156f4bSDave Marchevsky end_of_jmp = prog;
1497588a25e9SAlexei Starovoitov
14984c5de127SAlexei Starovoitov /* xor dst_reg, dst_reg */
14994c5de127SAlexei Starovoitov emit_mov_imm32(&prog, false, dst_reg, 0);
15004c5de127SAlexei Starovoitov /* jmp byte_after_ldx */
15014c5de127SAlexei Starovoitov EMIT2(0xEB, 0);
15024c5de127SAlexei Starovoitov
150390156f4bSDave Marchevsky /* populate jmp_offset for JAE above to jump to start_of_ldx */
15044c5de127SAlexei Starovoitov start_of_ldx = prog;
150590156f4bSDave Marchevsky end_of_jmp[-1] = start_of_ldx - end_of_jmp;
15064c5de127SAlexei Starovoitov }
15071f9a1ea8SYonghong Song if (BPF_MODE(insn->code) == BPF_PROBE_MEMSX ||
15081f9a1ea8SYonghong Song BPF_MODE(insn->code) == BPF_MEMSX)
15091f9a1ea8SYonghong Song emit_ldsx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn_off);
15101f9a1ea8SYonghong Song else
151190156f4bSDave Marchevsky emit_ldx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn_off);
15121f9a1ea8SYonghong Song if (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
15131f9a1ea8SYonghong Song BPF_MODE(insn->code) == BPF_PROBE_MEMSX) {
15143dec541bSAlexei Starovoitov struct exception_table_entry *ex;
1515328aac5eSRavi Bangoria u8 *_insn = image + proglen + (start_of_ldx - temp);
15163dec541bSAlexei Starovoitov s64 delta;
15173dec541bSAlexei Starovoitov
15184c5de127SAlexei Starovoitov /* populate jmp_offset for JMP above */
15194c5de127SAlexei Starovoitov start_of_ldx[-1] = prog - start_of_ldx;
15204c5de127SAlexei Starovoitov
15213dec541bSAlexei Starovoitov if (!bpf_prog->aux->extable)
15223dec541bSAlexei Starovoitov break;
15233dec541bSAlexei Starovoitov
15243dec541bSAlexei Starovoitov if (excnt >= bpf_prog->aux->num_exentries) {
15253dec541bSAlexei Starovoitov pr_err("ex gen bug\n");
15263dec541bSAlexei Starovoitov return -EFAULT;
15273dec541bSAlexei Starovoitov }
15283dec541bSAlexei Starovoitov ex = &bpf_prog->aux->extable[excnt++];
15293dec541bSAlexei Starovoitov
15303dec541bSAlexei Starovoitov delta = _insn - (u8 *)&ex->insn;
15313dec541bSAlexei Starovoitov if (!is_simm32(delta)) {
15323dec541bSAlexei Starovoitov pr_err("extable->insn doesn't fit into 32-bit\n");
15333dec541bSAlexei Starovoitov return -EFAULT;
15343dec541bSAlexei Starovoitov }
15351022a549SSong Liu /* switch ex to rw buffer for writes */
15361022a549SSong Liu ex = (void *)rw_image + ((void *)ex - (void *)image);
15371022a549SSong Liu
15383dec541bSAlexei Starovoitov ex->insn = delta;
15393dec541bSAlexei Starovoitov
15404b5305deSPeter Zijlstra ex->data = EX_TYPE_BPF;
15413dec541bSAlexei Starovoitov
15423dec541bSAlexei Starovoitov if (dst_reg > BPF_REG_9) {
15433dec541bSAlexei Starovoitov pr_err("verifier error\n");
15443dec541bSAlexei Starovoitov return -EFAULT;
15453dec541bSAlexei Starovoitov }
15463dec541bSAlexei Starovoitov /*
15473dec541bSAlexei Starovoitov * Compute size of x86 insn and its target dest x86 register.
15483dec541bSAlexei Starovoitov * ex_handler_bpf() will use lower 8 bits to adjust
15493dec541bSAlexei Starovoitov * pt_regs->ip to jump over this x86 instruction
15503dec541bSAlexei Starovoitov * and upper bits to figure out which pt_regs to zero out.
15513dec541bSAlexei Starovoitov * End result: x86 insn "mov rbx, qword ptr [rax+0x14]"
15523dec541bSAlexei Starovoitov * of 4 bytes will be ignored and rbx will be zero inited.
15533dec541bSAlexei Starovoitov */
1554433956e9SAlexei Starovoitov ex->fixup = (prog - start_of_ldx) | (reg2pt_regs[dst_reg] << 8);
15553dec541bSAlexei Starovoitov }
155662258278SAlexei Starovoitov break;
155762258278SAlexei Starovoitov
155891c960b0SBrendan Jackman case BPF_STX | BPF_ATOMIC | BPF_W:
155991c960b0SBrendan Jackman case BPF_STX | BPF_ATOMIC | BPF_DW:
1560981f94c3SBrendan Jackman if (insn->imm == (BPF_AND | BPF_FETCH) ||
1561981f94c3SBrendan Jackman insn->imm == (BPF_OR | BPF_FETCH) ||
1562981f94c3SBrendan Jackman insn->imm == (BPF_XOR | BPF_FETCH)) {
1563981f94c3SBrendan Jackman bool is64 = BPF_SIZE(insn->code) == BPF_DW;
1564b29dd96bSBrendan Jackman u32 real_src_reg = src_reg;
1565ced18582SJohan Almbladh u32 real_dst_reg = dst_reg;
1566ced18582SJohan Almbladh u8 *branch_target;
1567981f94c3SBrendan Jackman
1568981f94c3SBrendan Jackman /*
1569981f94c3SBrendan Jackman * Can't be implemented with a single x86 insn.
1570981f94c3SBrendan Jackman * Need to do a CMPXCHG loop.
1571981f94c3SBrendan Jackman */
1572981f94c3SBrendan Jackman
1573981f94c3SBrendan Jackman /* Will need RAX as a CMPXCHG operand so save R0 */
1574981f94c3SBrendan Jackman emit_mov_reg(&prog, true, BPF_REG_AX, BPF_REG_0);
1575b29dd96bSBrendan Jackman if (src_reg == BPF_REG_0)
1576b29dd96bSBrendan Jackman real_src_reg = BPF_REG_AX;
1577ced18582SJohan Almbladh if (dst_reg == BPF_REG_0)
1578ced18582SJohan Almbladh real_dst_reg = BPF_REG_AX;
1579b29dd96bSBrendan Jackman
1580981f94c3SBrendan Jackman branch_target = prog;
1581981f94c3SBrendan Jackman /* Load old value */
1582981f94c3SBrendan Jackman emit_ldx(&prog, BPF_SIZE(insn->code),
1583ced18582SJohan Almbladh BPF_REG_0, real_dst_reg, insn->off);
1584981f94c3SBrendan Jackman /*
1585981f94c3SBrendan Jackman * Perform the (commutative) operation locally,
1586981f94c3SBrendan Jackman * put the result in the AUX_REG.
1587981f94c3SBrendan Jackman */
1588981f94c3SBrendan Jackman emit_mov_reg(&prog, is64, AUX_REG, BPF_REG_0);
1589b29dd96bSBrendan Jackman maybe_emit_mod(&prog, AUX_REG, real_src_reg, is64);
1590981f94c3SBrendan Jackman EMIT2(simple_alu_opcodes[BPF_OP(insn->imm)],
1591b29dd96bSBrendan Jackman add_2reg(0xC0, AUX_REG, real_src_reg));
1592981f94c3SBrendan Jackman /* Attempt to swap in new value */
1593981f94c3SBrendan Jackman err = emit_atomic(&prog, BPF_CMPXCHG,
1594ced18582SJohan Almbladh real_dst_reg, AUX_REG,
1595ced18582SJohan Almbladh insn->off,
1596981f94c3SBrendan Jackman BPF_SIZE(insn->code));
1597981f94c3SBrendan Jackman if (WARN_ON(err))
1598981f94c3SBrendan Jackman return err;
1599981f94c3SBrendan Jackman /*
1600981f94c3SBrendan Jackman * ZF tells us whether we won the race. If it's
1601981f94c3SBrendan Jackman * cleared we need to try again.
1602981f94c3SBrendan Jackman */
1603981f94c3SBrendan Jackman EMIT2(X86_JNE, -(prog - branch_target) - 2);
1604981f94c3SBrendan Jackman /* Return the pre-modification value */
1605b29dd96bSBrendan Jackman emit_mov_reg(&prog, is64, real_src_reg, BPF_REG_0);
1606981f94c3SBrendan Jackman /* Restore R0 after clobbering RAX */
1607981f94c3SBrendan Jackman emit_mov_reg(&prog, true, BPF_REG_0, BPF_REG_AX);
1608981f94c3SBrendan Jackman break;
1609981f94c3SBrendan Jackman }
1610981f94c3SBrendan Jackman
161191c960b0SBrendan Jackman err = emit_atomic(&prog, insn->imm, dst_reg, src_reg,
161291c960b0SBrendan Jackman insn->off, BPF_SIZE(insn->code));
161391c960b0SBrendan Jackman if (err)
161491c960b0SBrendan Jackman return err;
161562258278SAlexei Starovoitov break;
161662258278SAlexei Starovoitov
161762258278SAlexei Starovoitov /* call */
1618b2e9dfe5SThomas Gleixner case BPF_JMP | BPF_CALL: {
1619b2e9dfe5SThomas Gleixner int offs;
1620b2e9dfe5SThomas Gleixner
1621e430f34eSAlexei Starovoitov func = (u8 *) __bpf_call_base + imm32;
1622ebf7d1f5SMaciej Fijalkowski if (tail_call_reachable) {
16238f873cc3SLeon Hwang RESTORE_TAIL_CALL_CNT(bpf_prog->aux->stack_depth);
1624b2e9dfe5SThomas Gleixner if (!imm32)
1625ebf7d1f5SMaciej Fijalkowski return -EINVAL;
1626b2e9dfe5SThomas Gleixner offs = 7 + x86_call_depth_emit_accounting(&prog, func);
1627ebf7d1f5SMaciej Fijalkowski } else {
1628b2e9dfe5SThomas Gleixner if (!imm32)
1629f3c2af7bSAlexei Starovoitov return -EINVAL;
1630b2e9dfe5SThomas Gleixner offs = x86_call_depth_emit_accounting(&prog, func);
1631ebf7d1f5SMaciej Fijalkowski }
1632b2e9dfe5SThomas Gleixner if (emit_call(&prog, func, image + addrs[i - 1] + offs))
1633b2e9dfe5SThomas Gleixner return -EINVAL;
163462258278SAlexei Starovoitov break;
1635b2e9dfe5SThomas Gleixner }
163662258278SAlexei Starovoitov
163771189fa9SAlexei Starovoitov case BPF_JMP | BPF_TAIL_CALL:
1638428d5df1SDaniel Borkmann if (imm32)
1639428d5df1SDaniel Borkmann emit_bpf_tail_call_direct(&bpf_prog->aux->poke_tab[imm32 - 1],
1640dceba081SPeter Zijlstra &prog, image + addrs[i - 1],
1641ebf7d1f5SMaciej Fijalkowski callee_regs_used,
1642dceba081SPeter Zijlstra bpf_prog->aux->stack_depth,
1643dceba081SPeter Zijlstra ctx);
1644428d5df1SDaniel Borkmann else
1645ebf7d1f5SMaciej Fijalkowski emit_bpf_tail_call_indirect(&prog,
1646ebf7d1f5SMaciej Fijalkowski callee_regs_used,
1647dceba081SPeter Zijlstra bpf_prog->aux->stack_depth,
1648dceba081SPeter Zijlstra image + addrs[i - 1],
1649dceba081SPeter Zijlstra ctx);
1650b52f00e6SAlexei Starovoitov break;
1651b52f00e6SAlexei Starovoitov
165262258278SAlexei Starovoitov /* cond jump */
165362258278SAlexei Starovoitov case BPF_JMP | BPF_JEQ | BPF_X:
165462258278SAlexei Starovoitov case BPF_JMP | BPF_JNE | BPF_X:
165562258278SAlexei Starovoitov case BPF_JMP | BPF_JGT | BPF_X:
165652afc51eSDaniel Borkmann case BPF_JMP | BPF_JLT | BPF_X:
165762258278SAlexei Starovoitov case BPF_JMP | BPF_JGE | BPF_X:
165852afc51eSDaniel Borkmann case BPF_JMP | BPF_JLE | BPF_X:
165962258278SAlexei Starovoitov case BPF_JMP | BPF_JSGT | BPF_X:
166052afc51eSDaniel Borkmann case BPF_JMP | BPF_JSLT | BPF_X:
166162258278SAlexei Starovoitov case BPF_JMP | BPF_JSGE | BPF_X:
166252afc51eSDaniel Borkmann case BPF_JMP | BPF_JSLE | BPF_X:
16633f5d6525SJiong Wang case BPF_JMP32 | BPF_JEQ | BPF_X:
16643f5d6525SJiong Wang case BPF_JMP32 | BPF_JNE | BPF_X:
16653f5d6525SJiong Wang case BPF_JMP32 | BPF_JGT | BPF_X:
16663f5d6525SJiong Wang case BPF_JMP32 | BPF_JLT | BPF_X:
16673f5d6525SJiong Wang case BPF_JMP32 | BPF_JGE | BPF_X:
16683f5d6525SJiong Wang case BPF_JMP32 | BPF_JLE | BPF_X:
16693f5d6525SJiong Wang case BPF_JMP32 | BPF_JSGT | BPF_X:
16703f5d6525SJiong Wang case BPF_JMP32 | BPF_JSLT | BPF_X:
16713f5d6525SJiong Wang case BPF_JMP32 | BPF_JSGE | BPF_X:
16723f5d6525SJiong Wang case BPF_JMP32 | BPF_JSLE | BPF_X:
1673e430f34eSAlexei Starovoitov /* cmp dst_reg, src_reg */
167474007cfcSBrendan Jackman maybe_emit_mod(&prog, dst_reg, src_reg,
167574007cfcSBrendan Jackman BPF_CLASS(insn->code) == BPF_JMP);
16763f5d6525SJiong Wang EMIT2(0x39, add_2reg(0xC0, dst_reg, src_reg));
167762258278SAlexei Starovoitov goto emit_cond_jmp;
167862258278SAlexei Starovoitov
167962258278SAlexei Starovoitov case BPF_JMP | BPF_JSET | BPF_X:
16803f5d6525SJiong Wang case BPF_JMP32 | BPF_JSET | BPF_X:
1681e430f34eSAlexei Starovoitov /* test dst_reg, src_reg */
168274007cfcSBrendan Jackman maybe_emit_mod(&prog, dst_reg, src_reg,
168374007cfcSBrendan Jackman BPF_CLASS(insn->code) == BPF_JMP);
16843f5d6525SJiong Wang EMIT2(0x85, add_2reg(0xC0, dst_reg, src_reg));
168562258278SAlexei Starovoitov goto emit_cond_jmp;
168662258278SAlexei Starovoitov
168762258278SAlexei Starovoitov case BPF_JMP | BPF_JSET | BPF_K:
16883f5d6525SJiong Wang case BPF_JMP32 | BPF_JSET | BPF_K:
1689e430f34eSAlexei Starovoitov /* test dst_reg, imm32 */
16906364d7d7SJie Meng maybe_emit_1mod(&prog, dst_reg,
16916364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_JMP);
1692e430f34eSAlexei Starovoitov EMIT2_off32(0xF7, add_1reg(0xC0, dst_reg), imm32);
169362258278SAlexei Starovoitov goto emit_cond_jmp;
169462258278SAlexei Starovoitov
169562258278SAlexei Starovoitov case BPF_JMP | BPF_JEQ | BPF_K:
169662258278SAlexei Starovoitov case BPF_JMP | BPF_JNE | BPF_K:
169762258278SAlexei Starovoitov case BPF_JMP | BPF_JGT | BPF_K:
169852afc51eSDaniel Borkmann case BPF_JMP | BPF_JLT | BPF_K:
169962258278SAlexei Starovoitov case BPF_JMP | BPF_JGE | BPF_K:
170052afc51eSDaniel Borkmann case BPF_JMP | BPF_JLE | BPF_K:
170162258278SAlexei Starovoitov case BPF_JMP | BPF_JSGT | BPF_K:
170252afc51eSDaniel Borkmann case BPF_JMP | BPF_JSLT | BPF_K:
170362258278SAlexei Starovoitov case BPF_JMP | BPF_JSGE | BPF_K:
170452afc51eSDaniel Borkmann case BPF_JMP | BPF_JSLE | BPF_K:
17053f5d6525SJiong Wang case BPF_JMP32 | BPF_JEQ | BPF_K:
17063f5d6525SJiong Wang case BPF_JMP32 | BPF_JNE | BPF_K:
17073f5d6525SJiong Wang case BPF_JMP32 | BPF_JGT | BPF_K:
17083f5d6525SJiong Wang case BPF_JMP32 | BPF_JLT | BPF_K:
17093f5d6525SJiong Wang case BPF_JMP32 | BPF_JGE | BPF_K:
17103f5d6525SJiong Wang case BPF_JMP32 | BPF_JLE | BPF_K:
17113f5d6525SJiong Wang case BPF_JMP32 | BPF_JSGT | BPF_K:
17123f5d6525SJiong Wang case BPF_JMP32 | BPF_JSLT | BPF_K:
17133f5d6525SJiong Wang case BPF_JMP32 | BPF_JSGE | BPF_K:
17143f5d6525SJiong Wang case BPF_JMP32 | BPF_JSLE | BPF_K:
171538f51c07SDaniel Borkmann /* test dst_reg, dst_reg to save one extra byte */
171638f51c07SDaniel Borkmann if (imm32 == 0) {
171774007cfcSBrendan Jackman maybe_emit_mod(&prog, dst_reg, dst_reg,
171874007cfcSBrendan Jackman BPF_CLASS(insn->code) == BPF_JMP);
171938f51c07SDaniel Borkmann EMIT2(0x85, add_2reg(0xC0, dst_reg, dst_reg));
172038f51c07SDaniel Borkmann goto emit_cond_jmp;
172138f51c07SDaniel Borkmann }
172238f51c07SDaniel Borkmann
1723e430f34eSAlexei Starovoitov /* cmp dst_reg, imm8/32 */
17246364d7d7SJie Meng maybe_emit_1mod(&prog, dst_reg,
17256364d7d7SJie Meng BPF_CLASS(insn->code) == BPF_JMP);
172662258278SAlexei Starovoitov
1727e430f34eSAlexei Starovoitov if (is_imm8(imm32))
1728e430f34eSAlexei Starovoitov EMIT3(0x83, add_1reg(0xF8, dst_reg), imm32);
172962258278SAlexei Starovoitov else
1730e430f34eSAlexei Starovoitov EMIT2_off32(0x81, add_1reg(0xF8, dst_reg), imm32);
173162258278SAlexei Starovoitov
1732a2c7a983SIngo Molnar emit_cond_jmp: /* Convert BPF opcode to x86 */
173362258278SAlexei Starovoitov switch (BPF_OP(insn->code)) {
173462258278SAlexei Starovoitov case BPF_JEQ:
173562258278SAlexei Starovoitov jmp_cond = X86_JE;
173662258278SAlexei Starovoitov break;
173762258278SAlexei Starovoitov case BPF_JSET:
173862258278SAlexei Starovoitov case BPF_JNE:
173962258278SAlexei Starovoitov jmp_cond = X86_JNE;
174062258278SAlexei Starovoitov break;
174162258278SAlexei Starovoitov case BPF_JGT:
174262258278SAlexei Starovoitov /* GT is unsigned '>', JA in x86 */
174362258278SAlexei Starovoitov jmp_cond = X86_JA;
174462258278SAlexei Starovoitov break;
174552afc51eSDaniel Borkmann case BPF_JLT:
174652afc51eSDaniel Borkmann /* LT is unsigned '<', JB in x86 */
174752afc51eSDaniel Borkmann jmp_cond = X86_JB;
174852afc51eSDaniel Borkmann break;
174962258278SAlexei Starovoitov case BPF_JGE:
175062258278SAlexei Starovoitov /* GE is unsigned '>=', JAE in x86 */
175162258278SAlexei Starovoitov jmp_cond = X86_JAE;
175262258278SAlexei Starovoitov break;
175352afc51eSDaniel Borkmann case BPF_JLE:
175452afc51eSDaniel Borkmann /* LE is unsigned '<=', JBE in x86 */
175552afc51eSDaniel Borkmann jmp_cond = X86_JBE;
175652afc51eSDaniel Borkmann break;
175762258278SAlexei Starovoitov case BPF_JSGT:
1758a2c7a983SIngo Molnar /* Signed '>', GT in x86 */
175962258278SAlexei Starovoitov jmp_cond = X86_JG;
176062258278SAlexei Starovoitov break;
176152afc51eSDaniel Borkmann case BPF_JSLT:
1762a2c7a983SIngo Molnar /* Signed '<', LT in x86 */
176352afc51eSDaniel Borkmann jmp_cond = X86_JL;
176452afc51eSDaniel Borkmann break;
176562258278SAlexei Starovoitov case BPF_JSGE:
1766a2c7a983SIngo Molnar /* Signed '>=', GE in x86 */
176762258278SAlexei Starovoitov jmp_cond = X86_JGE;
176862258278SAlexei Starovoitov break;
176952afc51eSDaniel Borkmann case BPF_JSLE:
1770a2c7a983SIngo Molnar /* Signed '<=', LE in x86 */
177152afc51eSDaniel Borkmann jmp_cond = X86_JLE;
177252afc51eSDaniel Borkmann break;
1773a2c7a983SIngo Molnar default: /* to silence GCC warning */
177462258278SAlexei Starovoitov return -EFAULT;
177562258278SAlexei Starovoitov }
177662258278SAlexei Starovoitov jmp_offset = addrs[i + insn->off] - addrs[i];
177762258278SAlexei Starovoitov if (is_imm8(jmp_offset)) {
177893c5aeccSGary Lin if (jmp_padding) {
177993c5aeccSGary Lin /* To keep the jmp_offset valid, the extra bytes are
1780d9f6e12fSIngo Molnar * padded before the jump insn, so we subtract the
178193c5aeccSGary Lin * 2 bytes of jmp_cond insn from INSN_SZ_DIFF.
178293c5aeccSGary Lin *
178393c5aeccSGary Lin * If the previous pass already emits an imm8
178493c5aeccSGary Lin * jmp_cond, then this BPF insn won't shrink, so
178593c5aeccSGary Lin * "nops" is 0.
178693c5aeccSGary Lin *
178793c5aeccSGary Lin * On the other hand, if the previous pass emits an
178893c5aeccSGary Lin * imm32 jmp_cond, the extra 4 bytes(*) is padded to
178993c5aeccSGary Lin * keep the image from shrinking further.
179093c5aeccSGary Lin *
179193c5aeccSGary Lin * (*) imm32 jmp_cond is 6 bytes, and imm8 jmp_cond
179293c5aeccSGary Lin * is 2 bytes, so the size difference is 4 bytes.
179393c5aeccSGary Lin */
179493c5aeccSGary Lin nops = INSN_SZ_DIFF - 2;
179593c5aeccSGary Lin if (nops != 0 && nops != 4) {
179693c5aeccSGary Lin pr_err("unexpected jmp_cond padding: %d bytes\n",
179793c5aeccSGary Lin nops);
179893c5aeccSGary Lin return -EFAULT;
179993c5aeccSGary Lin }
1800ced50fc4SJiri Olsa emit_nops(&prog, nops);
180193c5aeccSGary Lin }
180262258278SAlexei Starovoitov EMIT2(jmp_cond, jmp_offset);
180362258278SAlexei Starovoitov } else if (is_simm32(jmp_offset)) {
180462258278SAlexei Starovoitov EMIT2_off32(0x0F, jmp_cond + 0x10, jmp_offset);
18053b58908aSEric Dumazet } else {
180662258278SAlexei Starovoitov pr_err("cond_jmp gen bug %llx\n", jmp_offset);
180762258278SAlexei Starovoitov return -EFAULT;
18083b58908aSEric Dumazet }
180962258278SAlexei Starovoitov
18103b58908aSEric Dumazet break;
181162258278SAlexei Starovoitov
181262258278SAlexei Starovoitov case BPF_JMP | BPF_JA:
18134cd58e9aSYonghong Song case BPF_JMP32 | BPF_JA:
18144cd58e9aSYonghong Song if (BPF_CLASS(insn->code) == BPF_JMP) {
18151612a981SGianluca Borello if (insn->off == -1)
18161612a981SGianluca Borello /* -1 jmp instructions will always jump
18171612a981SGianluca Borello * backwards two bytes. Explicitly handling
18181612a981SGianluca Borello * this case avoids wasting too many passes
18191612a981SGianluca Borello * when there are long sequences of replaced
18201612a981SGianluca Borello * dead code.
18211612a981SGianluca Borello */
18221612a981SGianluca Borello jmp_offset = -2;
18231612a981SGianluca Borello else
182462258278SAlexei Starovoitov jmp_offset = addrs[i + insn->off] - addrs[i];
18254cd58e9aSYonghong Song } else {
18264cd58e9aSYonghong Song if (insn->imm == -1)
18274cd58e9aSYonghong Song jmp_offset = -2;
18284cd58e9aSYonghong Song else
18294cd58e9aSYonghong Song jmp_offset = addrs[i + insn->imm] - addrs[i];
18304cd58e9aSYonghong Song }
18311612a981SGianluca Borello
183293c5aeccSGary Lin if (!jmp_offset) {
183393c5aeccSGary Lin /*
183493c5aeccSGary Lin * If jmp_padding is enabled, the extra nops will
183593c5aeccSGary Lin * be inserted. Otherwise, optimize out nop jumps.
183693c5aeccSGary Lin */
183793c5aeccSGary Lin if (jmp_padding) {
183893c5aeccSGary Lin /* There are 3 possible conditions.
183993c5aeccSGary Lin * (1) This BPF_JA is already optimized out in
184093c5aeccSGary Lin * the previous run, so there is no need
184193c5aeccSGary Lin * to pad any extra byte (0 byte).
184293c5aeccSGary Lin * (2) The previous pass emits an imm8 jmp,
184393c5aeccSGary Lin * so we pad 2 bytes to match the previous
184493c5aeccSGary Lin * insn size.
184593c5aeccSGary Lin * (3) Similarly, the previous pass emits an
184693c5aeccSGary Lin * imm32 jmp, and 5 bytes is padded.
184793c5aeccSGary Lin */
184893c5aeccSGary Lin nops = INSN_SZ_DIFF;
184993c5aeccSGary Lin if (nops != 0 && nops != 2 && nops != 5) {
185093c5aeccSGary Lin pr_err("unexpected nop jump padding: %d bytes\n",
185193c5aeccSGary Lin nops);
185293c5aeccSGary Lin return -EFAULT;
185393c5aeccSGary Lin }
1854ced50fc4SJiri Olsa emit_nops(&prog, nops);
185593c5aeccSGary Lin }
185662258278SAlexei Starovoitov break;
185793c5aeccSGary Lin }
185862258278SAlexei Starovoitov emit_jmp:
185962258278SAlexei Starovoitov if (is_imm8(jmp_offset)) {
186093c5aeccSGary Lin if (jmp_padding) {
186193c5aeccSGary Lin /* To avoid breaking jmp_offset, the extra bytes
186293c5aeccSGary Lin * are padded before the actual jmp insn, so
1863d9f6e12fSIngo Molnar * 2 bytes is subtracted from INSN_SZ_DIFF.
186493c5aeccSGary Lin *
186593c5aeccSGary Lin * If the previous pass already emits an imm8
186693c5aeccSGary Lin * jmp, there is nothing to pad (0 byte).
186793c5aeccSGary Lin *
186893c5aeccSGary Lin * If it emits an imm32 jmp (5 bytes) previously
186993c5aeccSGary Lin * and now an imm8 jmp (2 bytes), then we pad
187093c5aeccSGary Lin * (5 - 2 = 3) bytes to stop the image from
187193c5aeccSGary Lin * shrinking further.
187293c5aeccSGary Lin */
187393c5aeccSGary Lin nops = INSN_SZ_DIFF - 2;
187493c5aeccSGary Lin if (nops != 0 && nops != 3) {
187593c5aeccSGary Lin pr_err("unexpected jump padding: %d bytes\n",
187693c5aeccSGary Lin nops);
187793c5aeccSGary Lin return -EFAULT;
187893c5aeccSGary Lin }
1879ced50fc4SJiri Olsa emit_nops(&prog, INSN_SZ_DIFF - 2);
188093c5aeccSGary Lin }
188162258278SAlexei Starovoitov EMIT2(0xEB, jmp_offset);
188262258278SAlexei Starovoitov } else if (is_simm32(jmp_offset)) {
188362258278SAlexei Starovoitov EMIT1_off32(0xE9, jmp_offset);
188462258278SAlexei Starovoitov } else {
188562258278SAlexei Starovoitov pr_err("jmp gen bug %llx\n", jmp_offset);
188662258278SAlexei Starovoitov return -EFAULT;
18873b58908aSEric Dumazet }
188862258278SAlexei Starovoitov break;
188962258278SAlexei Starovoitov
189062258278SAlexei Starovoitov case BPF_JMP | BPF_EXIT:
1891769e0de6SAlexei Starovoitov if (seen_exit) {
189262258278SAlexei Starovoitov jmp_offset = ctx->cleanup_addr - addrs[i];
189362258278SAlexei Starovoitov goto emit_jmp;
189462258278SAlexei Starovoitov }
1895769e0de6SAlexei Starovoitov seen_exit = true;
1896a2c7a983SIngo Molnar /* Update cleanup_addr */
189762258278SAlexei Starovoitov ctx->cleanup_addr = proglen;
1898ebf7d1f5SMaciej Fijalkowski pop_callee_regs(&prog, callee_regs_used);
189962258278SAlexei Starovoitov EMIT1(0xC9); /* leave */
1900d77cfe59SPeter Zijlstra emit_return(&prog, image + addrs[i - 1] + (prog - temp));
19010a14842fSEric Dumazet break;
19020a14842fSEric Dumazet
19030a14842fSEric Dumazet default:
1904a2c7a983SIngo Molnar /*
1905a2c7a983SIngo Molnar * By design x86-64 JIT should support all BPF instructions.
190662258278SAlexei Starovoitov * This error will be seen if new instruction was added
1907a2c7a983SIngo Molnar * to the interpreter, but not to the JIT, or if there is
1908a2c7a983SIngo Molnar * junk in bpf_prog.
190962258278SAlexei Starovoitov */
191062258278SAlexei Starovoitov pr_err("bpf_jit: unknown opcode %02x\n", insn->code);
1911f3c2af7bSAlexei Starovoitov return -EINVAL;
19120a14842fSEric Dumazet }
191362258278SAlexei Starovoitov
19140a14842fSEric Dumazet ilen = prog - temp;
1915e0ee9c12SAlexei Starovoitov if (ilen > BPF_MAX_INSN_SIZE) {
19169383191dSDaniel Borkmann pr_err("bpf_jit: fatal insn size error\n");
1917e0ee9c12SAlexei Starovoitov return -EFAULT;
1918e0ee9c12SAlexei Starovoitov }
1919e0ee9c12SAlexei Starovoitov
19200a14842fSEric Dumazet if (image) {
1921e4d4d456SPiotr Krysiuk /*
1922e4d4d456SPiotr Krysiuk * When populating the image, assert that:
1923e4d4d456SPiotr Krysiuk *
1924e4d4d456SPiotr Krysiuk * i) We do not write beyond the allocated space, and
1925e4d4d456SPiotr Krysiuk * ii) addrs[i] did not change from the prior run, in order
1926e4d4d456SPiotr Krysiuk * to validate assumptions made for computing branch
1927e4d4d456SPiotr Krysiuk * displacements.
1928e4d4d456SPiotr Krysiuk */
1929e4d4d456SPiotr Krysiuk if (unlikely(proglen + ilen > oldproglen ||
1930e4d4d456SPiotr Krysiuk proglen + ilen != addrs[i])) {
19319383191dSDaniel Borkmann pr_err("bpf_jit: fatal error\n");
1932f3c2af7bSAlexei Starovoitov return -EFAULT;
19330a14842fSEric Dumazet }
19341022a549SSong Liu memcpy(rw_image + proglen, temp, ilen);
19350a14842fSEric Dumazet }
19360a14842fSEric Dumazet proglen += ilen;
19370a14842fSEric Dumazet addrs[i] = proglen;
19380a14842fSEric Dumazet prog = temp;
19390a14842fSEric Dumazet }
19403dec541bSAlexei Starovoitov
19413dec541bSAlexei Starovoitov if (image && excnt != bpf_prog->aux->num_exentries) {
19423dec541bSAlexei Starovoitov pr_err("extable is not populated\n");
19433dec541bSAlexei Starovoitov return -EFAULT;
19443dec541bSAlexei Starovoitov }
1945f3c2af7bSAlexei Starovoitov return proglen;
1946f3c2af7bSAlexei Starovoitov }
1947f3c2af7bSAlexei Starovoitov
clean_stack_garbage(const struct btf_func_model * m,u8 ** pprog,int nr_stack_slots,int stack_size)1948473e3150SMenglong Dong static void clean_stack_garbage(const struct btf_func_model *m,
1949473e3150SMenglong Dong u8 **pprog, int nr_stack_slots,
1950fec56f58SAlexei Starovoitov int stack_size)
1951fec56f58SAlexei Starovoitov {
1952473e3150SMenglong Dong int arg_size, off;
1953473e3150SMenglong Dong u8 *prog;
1954473e3150SMenglong Dong
1955473e3150SMenglong Dong /* Generally speaking, the compiler will pass the arguments
1956473e3150SMenglong Dong * on-stack with "push" instruction, which will take 8-byte
1957473e3150SMenglong Dong * on the stack. In this case, there won't be garbage values
1958473e3150SMenglong Dong * while we copy the arguments from origin stack frame to current
1959473e3150SMenglong Dong * in BPF_DW.
1960473e3150SMenglong Dong *
1961473e3150SMenglong Dong * However, sometimes the compiler will only allocate 4-byte on
1962473e3150SMenglong Dong * the stack for the arguments. For now, this case will only
1963473e3150SMenglong Dong * happen if there is only one argument on-stack and its size
1964473e3150SMenglong Dong * not more than 4 byte. In this case, there will be garbage
1965473e3150SMenglong Dong * values on the upper 4-byte where we store the argument on
1966473e3150SMenglong Dong * current stack frame.
1967473e3150SMenglong Dong *
1968473e3150SMenglong Dong * arguments on origin stack:
1969473e3150SMenglong Dong *
1970473e3150SMenglong Dong * stack_arg_1(4-byte) xxx(4-byte)
1971473e3150SMenglong Dong *
1972473e3150SMenglong Dong * what we copy:
1973473e3150SMenglong Dong *
1974473e3150SMenglong Dong * stack_arg_1(8-byte): stack_arg_1(origin) xxx
1975473e3150SMenglong Dong *
1976473e3150SMenglong Dong * and the xxx is the garbage values which we should clean here.
1977473e3150SMenglong Dong */
1978473e3150SMenglong Dong if (nr_stack_slots != 1)
1979473e3150SMenglong Dong return;
1980473e3150SMenglong Dong
1981473e3150SMenglong Dong /* the size of the last argument */
1982473e3150SMenglong Dong arg_size = m->arg_size[m->nr_args - 1];
1983473e3150SMenglong Dong if (arg_size <= 4) {
1984473e3150SMenglong Dong off = -(stack_size - 4);
1985473e3150SMenglong Dong prog = *pprog;
1986473e3150SMenglong Dong /* mov DWORD PTR [rbp + off], 0 */
1987473e3150SMenglong Dong if (!is_imm8(off))
1988473e3150SMenglong Dong EMIT2_off32(0xC7, 0x85, off);
1989473e3150SMenglong Dong else
1990473e3150SMenglong Dong EMIT3(0xC7, 0x45, off);
1991473e3150SMenglong Dong EMIT(0, 4);
1992473e3150SMenglong Dong *pprog = prog;
1993473e3150SMenglong Dong }
1994473e3150SMenglong Dong }
1995473e3150SMenglong Dong
1996473e3150SMenglong Dong /* get the count of the regs that are used to pass arguments */
get_nr_used_regs(const struct btf_func_model * m)1997473e3150SMenglong Dong static int get_nr_used_regs(const struct btf_func_model *m)
1998473e3150SMenglong Dong {
1999473e3150SMenglong Dong int i, arg_regs, nr_used_regs = 0;
2000473e3150SMenglong Dong
2001473e3150SMenglong Dong for (i = 0; i < min_t(int, m->nr_args, MAX_BPF_FUNC_ARGS); i++) {
2002473e3150SMenglong Dong arg_regs = (m->arg_size[i] + 7) / 8;
2003473e3150SMenglong Dong if (nr_used_regs + arg_regs <= 6)
2004473e3150SMenglong Dong nr_used_regs += arg_regs;
2005473e3150SMenglong Dong
2006473e3150SMenglong Dong if (nr_used_regs >= 6)
2007473e3150SMenglong Dong break;
2008473e3150SMenglong Dong }
2009473e3150SMenglong Dong
2010473e3150SMenglong Dong return nr_used_regs;
2011473e3150SMenglong Dong }
2012473e3150SMenglong Dong
save_args(const struct btf_func_model * m,u8 ** prog,int stack_size,bool for_call_origin)2013473e3150SMenglong Dong static void save_args(const struct btf_func_model *m, u8 **prog,
2014473e3150SMenglong Dong int stack_size, bool for_call_origin)
2015473e3150SMenglong Dong {
2016492e797fSMenglong Dong int arg_regs, first_off = 0, nr_regs = 0, nr_stack_slots = 0;
2017473e3150SMenglong Dong int i, j;
20187f788049SPu Lehui
2019fec56f58SAlexei Starovoitov /* Store function arguments to stack.
2020fec56f58SAlexei Starovoitov * For a function that accepts two pointers the sequence will be:
2021fec56f58SAlexei Starovoitov * mov QWORD PTR [rbp-0x10],rdi
2022fec56f58SAlexei Starovoitov * mov QWORD PTR [rbp-0x8],rsi
2023fec56f58SAlexei Starovoitov */
2024473e3150SMenglong Dong for (i = 0; i < min_t(int, m->nr_args, MAX_BPF_FUNC_ARGS); i++) {
2025473e3150SMenglong Dong arg_regs = (m->arg_size[i] + 7) / 8;
2026473e3150SMenglong Dong
2027473e3150SMenglong Dong /* According to the research of Yonghong, struct members
2028473e3150SMenglong Dong * should be all in register or all on the stack.
2029473e3150SMenglong Dong * Meanwhile, the compiler will pass the argument on regs
2030473e3150SMenglong Dong * if the remaining regs can hold the argument.
2031473e3150SMenglong Dong *
2032473e3150SMenglong Dong * Disorder of the args can happen. For example:
2033473e3150SMenglong Dong *
2034473e3150SMenglong Dong * struct foo_struct {
2035473e3150SMenglong Dong * long a;
2036473e3150SMenglong Dong * int b;
2037473e3150SMenglong Dong * };
2038473e3150SMenglong Dong * int foo(char, char, char, char, char, struct foo_struct,
2039473e3150SMenglong Dong * char);
2040473e3150SMenglong Dong *
2041473e3150SMenglong Dong * the arg1-5,arg7 will be passed by regs, and arg6 will
2042473e3150SMenglong Dong * by stack.
2043473e3150SMenglong Dong */
2044473e3150SMenglong Dong if (nr_regs + arg_regs > 6) {
2045473e3150SMenglong Dong /* copy function arguments from origin stack frame
2046473e3150SMenglong Dong * into current stack frame.
2047473e3150SMenglong Dong *
2048473e3150SMenglong Dong * The starting address of the arguments on-stack
2049473e3150SMenglong Dong * is:
2050473e3150SMenglong Dong * rbp + 8(push rbp) +
2051473e3150SMenglong Dong * 8(return addr of origin call) +
2052473e3150SMenglong Dong * 8(return addr of the caller)
2053473e3150SMenglong Dong * which means: rbp + 24
2054473e3150SMenglong Dong */
2055473e3150SMenglong Dong for (j = 0; j < arg_regs; j++) {
2056473e3150SMenglong Dong emit_ldx(prog, BPF_DW, BPF_REG_0, BPF_REG_FP,
2057473e3150SMenglong Dong nr_stack_slots * 8 + 0x18);
2058473e3150SMenglong Dong emit_stx(prog, BPF_DW, BPF_REG_FP, BPF_REG_0,
2059473e3150SMenglong Dong -stack_size);
2060473e3150SMenglong Dong
2061473e3150SMenglong Dong if (!nr_stack_slots)
2062473e3150SMenglong Dong first_off = stack_size;
2063473e3150SMenglong Dong stack_size -= 8;
2064473e3150SMenglong Dong nr_stack_slots++;
2065473e3150SMenglong Dong }
2066473e3150SMenglong Dong } else {
2067473e3150SMenglong Dong /* Only copy the arguments on-stack to current
2068473e3150SMenglong Dong * 'stack_size' and ignore the regs, used to
2069473e3150SMenglong Dong * prepare the arguments on-stack for orign call.
2070473e3150SMenglong Dong */
2071473e3150SMenglong Dong if (for_call_origin) {
2072473e3150SMenglong Dong nr_regs += arg_regs;
2073473e3150SMenglong Dong continue;
2074fec56f58SAlexei Starovoitov }
2075fec56f58SAlexei Starovoitov
2076473e3150SMenglong Dong /* copy the arguments from regs into stack */
2077473e3150SMenglong Dong for (j = 0; j < arg_regs; j++) {
2078473e3150SMenglong Dong emit_stx(prog, BPF_DW, BPF_REG_FP,
2079473e3150SMenglong Dong nr_regs == 5 ? X86_REG_R9 : BPF_REG_1 + nr_regs,
2080473e3150SMenglong Dong -stack_size);
2081473e3150SMenglong Dong stack_size -= 8;
2082473e3150SMenglong Dong nr_regs++;
2083473e3150SMenglong Dong }
2084473e3150SMenglong Dong }
2085473e3150SMenglong Dong }
2086473e3150SMenglong Dong
2087473e3150SMenglong Dong clean_stack_garbage(m, prog, nr_stack_slots, first_off);
2088473e3150SMenglong Dong }
2089473e3150SMenglong Dong
restore_regs(const struct btf_func_model * m,u8 ** prog,int stack_size)2090473e3150SMenglong Dong static void restore_regs(const struct btf_func_model *m, u8 **prog,
2091fec56f58SAlexei Starovoitov int stack_size)
2092fec56f58SAlexei Starovoitov {
2093473e3150SMenglong Dong int i, j, arg_regs, nr_regs = 0;
2094fec56f58SAlexei Starovoitov
2095fec56f58SAlexei Starovoitov /* Restore function arguments from stack.
2096fec56f58SAlexei Starovoitov * For a function that accepts two pointers the sequence will be:
2097fec56f58SAlexei Starovoitov * EMIT4(0x48, 0x8B, 0x7D, 0xF0); mov rdi,QWORD PTR [rbp-0x10]
2098fec56f58SAlexei Starovoitov * EMIT4(0x48, 0x8B, 0x75, 0xF8); mov rsi,QWORD PTR [rbp-0x8]
2099473e3150SMenglong Dong *
2100473e3150SMenglong Dong * The logic here is similar to what we do in save_args()
2101fec56f58SAlexei Starovoitov */
2102473e3150SMenglong Dong for (i = 0; i < min_t(int, m->nr_args, MAX_BPF_FUNC_ARGS); i++) {
2103473e3150SMenglong Dong arg_regs = (m->arg_size[i] + 7) / 8;
2104473e3150SMenglong Dong if (nr_regs + arg_regs <= 6) {
2105473e3150SMenglong Dong for (j = 0; j < arg_regs; j++) {
210602a6dfa8SMenglong Dong emit_ldx(prog, BPF_DW,
2107473e3150SMenglong Dong nr_regs == 5 ? X86_REG_R9 : BPF_REG_1 + nr_regs,
2108fec56f58SAlexei Starovoitov BPF_REG_FP,
2109473e3150SMenglong Dong -stack_size);
2110473e3150SMenglong Dong stack_size -= 8;
2111473e3150SMenglong Dong nr_regs++;
2112473e3150SMenglong Dong }
2113473e3150SMenglong Dong } else {
2114473e3150SMenglong Dong stack_size -= 8 * arg_regs;
2115473e3150SMenglong Dong }
2116473e3150SMenglong Dong
2117473e3150SMenglong Dong if (nr_regs >= 6)
2118473e3150SMenglong Dong break;
2119473e3150SMenglong Dong }
2120fec56f58SAlexei Starovoitov }
2121fec56f58SAlexei Starovoitov
invoke_bpf_prog(const struct btf_func_model * m,u8 ** pprog,struct bpf_tramp_link * l,int stack_size,int run_ctx_off,bool save_ret)21227e639208SKP Singh static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
2123f7e0beafSKui-Feng Lee struct bpf_tramp_link *l, int stack_size,
2124e384c7b7SKui-Feng Lee int run_ctx_off, bool save_ret)
2125fec56f58SAlexei Starovoitov {
2126fec56f58SAlexei Starovoitov u8 *prog = *pprog;
2127ca06f55bSAlexei Starovoitov u8 *jmp_insn;
2128e384c7b7SKui-Feng Lee int ctx_cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
2129f7e0beafSKui-Feng Lee struct bpf_prog *p = l->link.prog;
21302fcc8241SKui-Feng Lee u64 cookie = l->cookie;
2131fec56f58SAlexei Starovoitov
21322fcc8241SKui-Feng Lee /* mov rdi, cookie */
21332fcc8241SKui-Feng Lee emit_mov_imm64(&prog, BPF_REG_1, (long) cookie >> 32, (u32) (long) cookie);
2134e384c7b7SKui-Feng Lee
2135e384c7b7SKui-Feng Lee /* Prepare struct bpf_tramp_run_ctx.
2136e384c7b7SKui-Feng Lee *
2137e384c7b7SKui-Feng Lee * bpf_tramp_run_ctx is already preserved by
2138e384c7b7SKui-Feng Lee * arch_prepare_bpf_trampoline().
2139e384c7b7SKui-Feng Lee *
2140e384c7b7SKui-Feng Lee * mov QWORD PTR [rbp - run_ctx_off + ctx_cookie_off], rdi
2141e384c7b7SKui-Feng Lee */
2142e384c7b7SKui-Feng Lee emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_1, -run_ctx_off + ctx_cookie_off);
2143e384c7b7SKui-Feng Lee
2144ca06f55bSAlexei Starovoitov /* arg1: mov rdi, progs[i] */
2145ca06f55bSAlexei Starovoitov emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
2146e384c7b7SKui-Feng Lee /* arg2: lea rsi, [rbp - ctx_cookie_off] */
2147473e3150SMenglong Dong if (!is_imm8(-run_ctx_off))
2148473e3150SMenglong Dong EMIT3_off32(0x48, 0x8D, 0xB5, -run_ctx_off);
2149473e3150SMenglong Dong else
2150e384c7b7SKui-Feng Lee EMIT4(0x48, 0x8D, 0x75, -run_ctx_off);
2151e384c7b7SKui-Feng Lee
215294a85511SLinus Torvalds if (emit_rsb_call(&prog, bpf_trampoline_enter(p), prog))
2153fec56f58SAlexei Starovoitov return -EINVAL;
2154fec56f58SAlexei Starovoitov /* remember prog start time returned by __bpf_prog_enter */
2155fec56f58SAlexei Starovoitov emit_mov_reg(&prog, true, BPF_REG_6, BPF_REG_0);
2156fec56f58SAlexei Starovoitov
2157ca06f55bSAlexei Starovoitov /* if (__bpf_prog_enter*(prog) == 0)
2158ca06f55bSAlexei Starovoitov * goto skip_exec_of_prog;
2159ca06f55bSAlexei Starovoitov */
2160ca06f55bSAlexei Starovoitov EMIT3(0x48, 0x85, 0xC0); /* test rax,rax */
2161ca06f55bSAlexei Starovoitov /* emit 2 nops that will be replaced with JE insn */
2162ca06f55bSAlexei Starovoitov jmp_insn = prog;
2163ca06f55bSAlexei Starovoitov emit_nops(&prog, 2);
2164ca06f55bSAlexei Starovoitov
2165fec56f58SAlexei Starovoitov /* arg1: lea rdi, [rbp - stack_size] */
2166473e3150SMenglong Dong if (!is_imm8(-stack_size))
2167473e3150SMenglong Dong EMIT3_off32(0x48, 0x8D, 0xBD, -stack_size);
2168473e3150SMenglong Dong else
2169fec56f58SAlexei Starovoitov EMIT4(0x48, 0x8D, 0x7D, -stack_size);
2170fec56f58SAlexei Starovoitov /* arg2: progs[i]->insnsi for interpreter */
21717e639208SKP Singh if (!p->jited)
2172fec56f58SAlexei Starovoitov emit_mov_imm64(&prog, BPF_REG_2,
21737e639208SKP Singh (long) p->insnsi >> 32,
21747e639208SKP Singh (u32) (long) p->insnsi);
2175fec56f58SAlexei Starovoitov /* call JITed bpf program or interpreter */
2176b2e9dfe5SThomas Gleixner if (emit_rsb_call(&prog, p->bpf_func, prog))
2177fec56f58SAlexei Starovoitov return -EINVAL;
2178fec56f58SAlexei Starovoitov
2179356ed649SHou Tao /*
2180356ed649SHou Tao * BPF_TRAMP_MODIFY_RETURN trampolines can modify the return
2181ae240823SKP Singh * of the previous call which is then passed on the stack to
2182ae240823SKP Singh * the next BPF program.
2183356ed649SHou Tao *
2184356ed649SHou Tao * BPF_TRAMP_FENTRY trampoline may need to return the return
2185356ed649SHou Tao * value of BPF_PROG_TYPE_STRUCT_OPS prog.
2186ae240823SKP Singh */
2187356ed649SHou Tao if (save_ret)
2188ae240823SKP Singh emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
2189ae240823SKP Singh
2190ca06f55bSAlexei Starovoitov /* replace 2 nops with JE insn, since jmp target is known */
2191ca06f55bSAlexei Starovoitov jmp_insn[0] = X86_JE;
2192ca06f55bSAlexei Starovoitov jmp_insn[1] = prog - jmp_insn - 2;
2193ca06f55bSAlexei Starovoitov
2194fec56f58SAlexei Starovoitov /* arg1: mov rdi, progs[i] */
2195f2dd3b39SAlexei Starovoitov emit_mov_imm64(&prog, BPF_REG_1, (long) p >> 32, (u32) (long) p);
2196fec56f58SAlexei Starovoitov /* arg2: mov rsi, rbx <- start time in nsec */
2197fec56f58SAlexei Starovoitov emit_mov_reg(&prog, true, BPF_REG_2, BPF_REG_6);
2198e384c7b7SKui-Feng Lee /* arg3: lea rdx, [rbp - run_ctx_off] */
2199473e3150SMenglong Dong if (!is_imm8(-run_ctx_off))
2200473e3150SMenglong Dong EMIT3_off32(0x48, 0x8D, 0x95, -run_ctx_off);
2201473e3150SMenglong Dong else
2202e384c7b7SKui-Feng Lee EMIT4(0x48, 0x8D, 0x55, -run_ctx_off);
220394a85511SLinus Torvalds if (emit_rsb_call(&prog, bpf_trampoline_exit(p), prog))
2204fec56f58SAlexei Starovoitov return -EINVAL;
22057e639208SKP Singh
22067e639208SKP Singh *pprog = prog;
22077e639208SKP Singh return 0;
22087e639208SKP Singh }
22097e639208SKP Singh
emit_align(u8 ** pprog,u32 align)22107e639208SKP Singh static void emit_align(u8 **pprog, u32 align)
22117e639208SKP Singh {
22127e639208SKP Singh u8 *target, *prog = *pprog;
22137e639208SKP Singh
22147e639208SKP Singh target = PTR_ALIGN(prog, align);
22157e639208SKP Singh if (target != prog)
22167e639208SKP Singh emit_nops(&prog, target - prog);
22177e639208SKP Singh
22187e639208SKP Singh *pprog = prog;
22197e639208SKP Singh }
22207e639208SKP Singh
emit_cond_near_jump(u8 ** pprog,void * func,void * ip,u8 jmp_cond)22217e639208SKP Singh static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond)
22227e639208SKP Singh {
22237e639208SKP Singh u8 *prog = *pprog;
22247e639208SKP Singh s64 offset;
22257e639208SKP Singh
22267e639208SKP Singh offset = func - (ip + 2 + 4);
22277e639208SKP Singh if (!is_simm32(offset)) {
22287e639208SKP Singh pr_err("Target %p is out of range\n", func);
22297e639208SKP Singh return -EINVAL;
22307e639208SKP Singh }
22317e639208SKP Singh EMIT2_off32(0x0F, jmp_cond + 0x10, offset);
22327e639208SKP Singh *pprog = prog;
22337e639208SKP Singh return 0;
22347e639208SKP Singh }
22357e639208SKP Singh
invoke_bpf(const struct btf_func_model * m,u8 ** pprog,struct bpf_tramp_links * tl,int stack_size,int run_ctx_off,bool save_ret)22367e639208SKP Singh static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
2237f7e0beafSKui-Feng Lee struct bpf_tramp_links *tl, int stack_size,
2238e384c7b7SKui-Feng Lee int run_ctx_off, bool save_ret)
22397e639208SKP Singh {
22407e639208SKP Singh int i;
22417e639208SKP Singh u8 *prog = *pprog;
22427e639208SKP Singh
2243f7e0beafSKui-Feng Lee for (i = 0; i < tl->nr_links; i++) {
2244f7e0beafSKui-Feng Lee if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size,
2245e384c7b7SKui-Feng Lee run_ctx_off, save_ret))
22467e639208SKP Singh return -EINVAL;
2247fec56f58SAlexei Starovoitov }
2248fec56f58SAlexei Starovoitov *pprog = prog;
2249fec56f58SAlexei Starovoitov return 0;
2250fec56f58SAlexei Starovoitov }
2251fec56f58SAlexei Starovoitov
invoke_bpf_mod_ret(const struct btf_func_model * m,u8 ** pprog,struct bpf_tramp_links * tl,int stack_size,int run_ctx_off,u8 ** branches)2252ae240823SKP Singh static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog,
2253f7e0beafSKui-Feng Lee struct bpf_tramp_links *tl, int stack_size,
2254e384c7b7SKui-Feng Lee int run_ctx_off, u8 **branches)
2255ae240823SKP Singh {
2256ae240823SKP Singh u8 *prog = *pprog;
2257ced50fc4SJiri Olsa int i;
2258ae240823SKP Singh
2259ae240823SKP Singh /* The first fmod_ret program will receive a garbage return value.
2260ae240823SKP Singh * Set this to 0 to avoid confusing the program.
2261ae240823SKP Singh */
2262ae240823SKP Singh emit_mov_imm32(&prog, false, BPF_REG_0, 0);
2263ae240823SKP Singh emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
2264f7e0beafSKui-Feng Lee for (i = 0; i < tl->nr_links; i++) {
2265e384c7b7SKui-Feng Lee if (invoke_bpf_prog(m, &prog, tl->links[i], stack_size, run_ctx_off, true))
2266ae240823SKP Singh return -EINVAL;
2267ae240823SKP Singh
226813fac1d8SAlexei Starovoitov /* mod_ret prog stored return value into [rbp - 8]. Emit:
226913fac1d8SAlexei Starovoitov * if (*(u64 *)(rbp - 8) != 0)
2270ae240823SKP Singh * goto do_fexit;
2271ae240823SKP Singh */
227213fac1d8SAlexei Starovoitov /* cmp QWORD PTR [rbp - 0x8], 0x0 */
227313fac1d8SAlexei Starovoitov EMIT4(0x48, 0x83, 0x7d, 0xf8); EMIT1(0x00);
2274ae240823SKP Singh
2275ae240823SKP Singh /* Save the location of the branch and Generate 6 nops
2276ae240823SKP Singh * (4 bytes for an offset and 2 bytes for the jump) These nops
2277ae240823SKP Singh * are replaced with a conditional jump once do_fexit (i.e. the
2278ae240823SKP Singh * start of the fexit invocation) is finalized.
2279ae240823SKP Singh */
2280ae240823SKP Singh branches[i] = prog;
2281ae240823SKP Singh emit_nops(&prog, 4 + 2);
2282ae240823SKP Singh }
2283ae240823SKP Singh
2284ae240823SKP Singh *pprog = prog;
2285ae240823SKP Singh return 0;
2286ae240823SKP Singh }
2287ae240823SKP Singh
2288fec56f58SAlexei Starovoitov /* Example:
2289fec56f58SAlexei Starovoitov * __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
2290fec56f58SAlexei Starovoitov * its 'struct btf_func_model' will be nr_args=2
2291fec56f58SAlexei Starovoitov * The assembly code when eth_type_trans is executing after trampoline:
2292fec56f58SAlexei Starovoitov *
2293fec56f58SAlexei Starovoitov * push rbp
2294fec56f58SAlexei Starovoitov * mov rbp, rsp
2295fec56f58SAlexei Starovoitov * sub rsp, 16 // space for skb and dev
2296fec56f58SAlexei Starovoitov * push rbx // temp regs to pass start time
2297fec56f58SAlexei Starovoitov * mov qword ptr [rbp - 16], rdi // save skb pointer to stack
2298fec56f58SAlexei Starovoitov * mov qword ptr [rbp - 8], rsi // save dev pointer to stack
2299fec56f58SAlexei Starovoitov * call __bpf_prog_enter // rcu_read_lock and preempt_disable
2300fec56f58SAlexei Starovoitov * mov rbx, rax // remember start time in bpf stats are enabled
2301fec56f58SAlexei Starovoitov * lea rdi, [rbp - 16] // R1==ctx of bpf prog
2302fec56f58SAlexei Starovoitov * call addr_of_jited_FENTRY_prog
2303fec56f58SAlexei Starovoitov * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
2304fec56f58SAlexei Starovoitov * mov rsi, rbx // prog start time
2305fec56f58SAlexei Starovoitov * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
2306fec56f58SAlexei Starovoitov * mov rdi, qword ptr [rbp - 16] // restore skb pointer from stack
2307fec56f58SAlexei Starovoitov * mov rsi, qword ptr [rbp - 8] // restore dev pointer from stack
2308fec56f58SAlexei Starovoitov * pop rbx
2309fec56f58SAlexei Starovoitov * leave
2310fec56f58SAlexei Starovoitov * ret
2311fec56f58SAlexei Starovoitov *
2312fec56f58SAlexei Starovoitov * eth_type_trans has 5 byte nop at the beginning. These 5 bytes will be
2313fec56f58SAlexei Starovoitov * replaced with 'call generated_bpf_trampoline'. When it returns
2314fec56f58SAlexei Starovoitov * eth_type_trans will continue executing with original skb and dev pointers.
2315fec56f58SAlexei Starovoitov *
2316fec56f58SAlexei Starovoitov * The assembly code when eth_type_trans is called from trampoline:
2317fec56f58SAlexei Starovoitov *
2318fec56f58SAlexei Starovoitov * push rbp
2319fec56f58SAlexei Starovoitov * mov rbp, rsp
2320fec56f58SAlexei Starovoitov * sub rsp, 24 // space for skb, dev, return value
2321fec56f58SAlexei Starovoitov * push rbx // temp regs to pass start time
2322fec56f58SAlexei Starovoitov * mov qword ptr [rbp - 24], rdi // save skb pointer to stack
2323fec56f58SAlexei Starovoitov * mov qword ptr [rbp - 16], rsi // save dev pointer to stack
2324fec56f58SAlexei Starovoitov * call __bpf_prog_enter // rcu_read_lock and preempt_disable
2325fec56f58SAlexei Starovoitov * mov rbx, rax // remember start time if bpf stats are enabled
2326fec56f58SAlexei Starovoitov * lea rdi, [rbp - 24] // R1==ctx of bpf prog
2327fec56f58SAlexei Starovoitov * call addr_of_jited_FENTRY_prog // bpf prog can access skb and dev
2328fec56f58SAlexei Starovoitov * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
2329fec56f58SAlexei Starovoitov * mov rsi, rbx // prog start time
2330fec56f58SAlexei Starovoitov * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
2331fec56f58SAlexei Starovoitov * mov rdi, qword ptr [rbp - 24] // restore skb pointer from stack
2332fec56f58SAlexei Starovoitov * mov rsi, qword ptr [rbp - 16] // restore dev pointer from stack
2333fec56f58SAlexei Starovoitov * call eth_type_trans+5 // execute body of eth_type_trans
2334fec56f58SAlexei Starovoitov * mov qword ptr [rbp - 8], rax // save return value
2335fec56f58SAlexei Starovoitov * call __bpf_prog_enter // rcu_read_lock and preempt_disable
2336fec56f58SAlexei Starovoitov * mov rbx, rax // remember start time in bpf stats are enabled
2337fec56f58SAlexei Starovoitov * lea rdi, [rbp - 24] // R1==ctx of bpf prog
2338fec56f58SAlexei Starovoitov * call addr_of_jited_FEXIT_prog // bpf prog can access skb, dev, return value
2339fec56f58SAlexei Starovoitov * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
2340fec56f58SAlexei Starovoitov * mov rsi, rbx // prog start time
2341fec56f58SAlexei Starovoitov * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
2342fec56f58SAlexei Starovoitov * mov rax, qword ptr [rbp - 8] // restore eth_type_trans's return value
2343fec56f58SAlexei Starovoitov * pop rbx
2344fec56f58SAlexei Starovoitov * leave
2345fec56f58SAlexei Starovoitov * add rsp, 8 // skip eth_type_trans's frame
2346fec56f58SAlexei Starovoitov * ret // return to its caller
2347fec56f58SAlexei Starovoitov */
arch_prepare_bpf_trampoline(struct bpf_tramp_image * im,void * image,void * image_end,const struct btf_func_model * m,u32 flags,struct bpf_tramp_links * tlinks,void * func_addr)2348e21aa341SAlexei Starovoitov int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end,
234985d33df3SMartin KaFai Lau const struct btf_func_model *m, u32 flags,
2350f7e0beafSKui-Feng Lee struct bpf_tramp_links *tlinks,
23514d854f4fSJiri Olsa void *func_addr)
2352fec56f58SAlexei Starovoitov {
23537f788049SPu Lehui int i, ret, nr_regs = m->nr_args, stack_size = 0;
2354473e3150SMenglong Dong int regs_off, nregs_off, ip_off, run_ctx_off, arg_stack_off, rbx_off;
2355f7e0beafSKui-Feng Lee struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
2356f7e0beafSKui-Feng Lee struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
2357f7e0beafSKui-Feng Lee struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
23584d854f4fSJiri Olsa void *orig_call = func_addr;
2359ae240823SKP Singh u8 **branches = NULL;
2360fec56f58SAlexei Starovoitov u8 *prog;
2361356ed649SHou Tao bool save_ret;
2362fec56f58SAlexei Starovoitov
23637f788049SPu Lehui /* extra registers for struct arguments */
23647f788049SPu Lehui for (i = 0; i < m->nr_args; i++)
2365a9c5ad31SYonghong Song if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
23667f788049SPu Lehui nr_regs += (m->arg_size[i] + 7) / 8 - 1;
23677f788049SPu Lehui
2368473e3150SMenglong Dong /* x86-64 supports up to MAX_BPF_FUNC_ARGS arguments. 1-6
2369473e3150SMenglong Dong * are passed through regs, the remains are through stack.
2370473e3150SMenglong Dong */
2371473e3150SMenglong Dong if (nr_regs > MAX_BPF_FUNC_ARGS)
2372a9c5ad31SYonghong Song return -ENOTSUPP;
2373a9c5ad31SYonghong Song
23745edf6a19SJiri Olsa /* Generated trampoline stack layout:
23755edf6a19SJiri Olsa *
23765edf6a19SJiri Olsa * RBP + 8 [ return address ]
23775edf6a19SJiri Olsa * RBP + 0 [ RBP ]
23785edf6a19SJiri Olsa *
23795edf6a19SJiri Olsa * RBP - 8 [ return value ] BPF_TRAMP_F_CALL_ORIG or
23805edf6a19SJiri Olsa * BPF_TRAMP_F_RET_FENTRY_RET flags
23815edf6a19SJiri Olsa *
23825edf6a19SJiri Olsa * [ reg_argN ] always
23835edf6a19SJiri Olsa * [ ... ]
23845edf6a19SJiri Olsa * RBP - regs_off [ reg_arg1 ] program's ctx pointer
23855edf6a19SJiri Olsa *
23867f788049SPu Lehui * RBP - nregs_off [ regs count ] always
2387f92c1e18SJiri Olsa *
23885edf6a19SJiri Olsa * RBP - ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag
2389e384c7b7SKui-Feng Lee *
2390473e3150SMenglong Dong * RBP - rbx_off [ rbx value ] always
2391473e3150SMenglong Dong *
2392e384c7b7SKui-Feng Lee * RBP - run_ctx_off [ bpf_tramp_run_ctx ]
2393473e3150SMenglong Dong *
2394473e3150SMenglong Dong * [ stack_argN ] BPF_TRAMP_F_CALL_ORIG
2395473e3150SMenglong Dong * [ ... ]
2396473e3150SMenglong Dong * [ stack_arg2 ]
2397473e3150SMenglong Dong * RBP - arg_stack_off [ stack_arg1 ]
23988f873cc3SLeon Hwang * RSP [ tail_call_cnt ] BPF_TRAMP_F_TAIL_CALL_CTX
23995edf6a19SJiri Olsa */
24005edf6a19SJiri Olsa
2401356ed649SHou Tao /* room for return value of orig_call or fentry prog */
2402356ed649SHou Tao save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
2403356ed649SHou Tao if (save_ret)
2404356ed649SHou Tao stack_size += 8;
2405fec56f58SAlexei Starovoitov
24067f788049SPu Lehui stack_size += nr_regs * 8;
24075edf6a19SJiri Olsa regs_off = stack_size;
24085edf6a19SJiri Olsa
24097f788049SPu Lehui /* regs count */
2410f92c1e18SJiri Olsa stack_size += 8;
24117f788049SPu Lehui nregs_off = stack_size;
2412f92c1e18SJiri Olsa
24137e6f3cd8SJiri Olsa if (flags & BPF_TRAMP_F_IP_ARG)
24147e6f3cd8SJiri Olsa stack_size += 8; /* room for IP address argument */
24157e6f3cd8SJiri Olsa
24165edf6a19SJiri Olsa ip_off = stack_size;
24175edf6a19SJiri Olsa
2418473e3150SMenglong Dong stack_size += 8;
2419473e3150SMenglong Dong rbx_off = stack_size;
2420473e3150SMenglong Dong
2421e384c7b7SKui-Feng Lee stack_size += (sizeof(struct bpf_tramp_run_ctx) + 7) & ~0x7;
2422e384c7b7SKui-Feng Lee run_ctx_off = stack_size;
2423e384c7b7SKui-Feng Lee
2424473e3150SMenglong Dong if (nr_regs > 6 && (flags & BPF_TRAMP_F_CALL_ORIG)) {
2425473e3150SMenglong Dong /* the space that used to pass arguments on-stack */
2426473e3150SMenglong Dong stack_size += (nr_regs - get_nr_used_regs(m)) * 8;
2427473e3150SMenglong Dong /* make sure the stack pointer is 16-byte aligned if we
2428473e3150SMenglong Dong * need pass arguments on stack, which means
2429473e3150SMenglong Dong * [stack_size + 8(rbp) + 8(rip) + 8(origin rip)]
2430473e3150SMenglong Dong * should be 16-byte aligned. Following code depend on
2431473e3150SMenglong Dong * that stack_size is already 8-byte aligned.
2432473e3150SMenglong Dong */
2433473e3150SMenglong Dong stack_size += (stack_size % 16) ? 0 : 8;
2434473e3150SMenglong Dong }
2435473e3150SMenglong Dong
2436473e3150SMenglong Dong arg_stack_off = stack_size;
2437473e3150SMenglong Dong
243858912710SPeter Zijlstra if (flags & BPF_TRAMP_F_SKIP_FRAME) {
2439fec56f58SAlexei Starovoitov /* skip patched call instruction and point orig_call to actual
2440fec56f58SAlexei Starovoitov * body of the kernel function.
2441fec56f58SAlexei Starovoitov */
244258912710SPeter Zijlstra if (is_endbr(*(u32 *)orig_call))
244358912710SPeter Zijlstra orig_call += ENDBR_INSN_SIZE;
24444b3da77bSDaniel Borkmann orig_call += X86_PATCH_SIZE;
244558912710SPeter Zijlstra }
2446fec56f58SAlexei Starovoitov
2447fec56f58SAlexei Starovoitov prog = image;
2448fec56f58SAlexei Starovoitov
244958912710SPeter Zijlstra EMIT_ENDBR();
2450ee3e2469SPeter Zijlstra /*
2451ee3e2469SPeter Zijlstra * This is the direct-call trampoline, as such it needs accounting
2452ee3e2469SPeter Zijlstra * for the __fentry__ call.
2453ee3e2469SPeter Zijlstra */
2454ee3e2469SPeter Zijlstra x86_call_depth_emit_accounting(&prog, NULL);
2455fec56f58SAlexei Starovoitov EMIT1(0x55); /* push rbp */
2456fec56f58SAlexei Starovoitov EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
2457473e3150SMenglong Dong if (!is_imm8(stack_size))
2458473e3150SMenglong Dong /* sub rsp, stack_size */
2459473e3150SMenglong Dong EMIT3_off32(0x48, 0x81, 0xEC, stack_size);
2460473e3150SMenglong Dong else
2461473e3150SMenglong Dong /* sub rsp, stack_size */
2462473e3150SMenglong Dong EMIT4(0x48, 0x83, 0xEC, stack_size);
24638f873cc3SLeon Hwang if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
24648f873cc3SLeon Hwang EMIT1(0x50); /* push rax */
2465473e3150SMenglong Dong /* mov QWORD PTR [rbp - rbx_off], rbx */
2466473e3150SMenglong Dong emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_6, -rbx_off);
2467fec56f58SAlexei Starovoitov
2468a9c5ad31SYonghong Song /* Store number of argument registers of the traced function:
24697f788049SPu Lehui * mov rax, nr_regs
24707f788049SPu Lehui * mov QWORD PTR [rbp - nregs_off], rax
2471f92c1e18SJiri Olsa */
24727f788049SPu Lehui emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_regs);
24737f788049SPu Lehui emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -nregs_off);
2474f92c1e18SJiri Olsa
24757e6f3cd8SJiri Olsa if (flags & BPF_TRAMP_F_IP_ARG) {
24767e6f3cd8SJiri Olsa /* Store IP address of the traced function:
24774d854f4fSJiri Olsa * movabsq rax, func_addr
24785edf6a19SJiri Olsa * mov QWORD PTR [rbp - ip_off], rax
24797e6f3cd8SJiri Olsa */
24804d854f4fSJiri Olsa emit_mov_imm64(&prog, BPF_REG_0, (long) func_addr >> 32, (u32) (long) func_addr);
24815edf6a19SJiri Olsa emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -ip_off);
24827e6f3cd8SJiri Olsa }
24837e6f3cd8SJiri Olsa
2484473e3150SMenglong Dong save_args(m, &prog, regs_off, false);
2485fec56f58SAlexei Starovoitov
2486e21aa341SAlexei Starovoitov if (flags & BPF_TRAMP_F_CALL_ORIG) {
2487e21aa341SAlexei Starovoitov /* arg1: mov rdi, im */
2488e21aa341SAlexei Starovoitov emit_mov_imm64(&prog, BPF_REG_1, (long) im >> 32, (u32) (long) im);
2489b2e9dfe5SThomas Gleixner if (emit_rsb_call(&prog, __bpf_tramp_enter, prog)) {
2490e21aa341SAlexei Starovoitov ret = -EINVAL;
2491e21aa341SAlexei Starovoitov goto cleanup;
2492e21aa341SAlexei Starovoitov }
2493e21aa341SAlexei Starovoitov }
2494e21aa341SAlexei Starovoitov
2495f7e0beafSKui-Feng Lee if (fentry->nr_links)
2496e384c7b7SKui-Feng Lee if (invoke_bpf(m, &prog, fentry, regs_off, run_ctx_off,
2497356ed649SHou Tao flags & BPF_TRAMP_F_RET_FENTRY_RET))
2498fec56f58SAlexei Starovoitov return -EINVAL;
2499fec56f58SAlexei Starovoitov
2500f7e0beafSKui-Feng Lee if (fmod_ret->nr_links) {
2501f7e0beafSKui-Feng Lee branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *),
2502ae240823SKP Singh GFP_KERNEL);
2503ae240823SKP Singh if (!branches)
2504ae240823SKP Singh return -ENOMEM;
2505ae240823SKP Singh
25065edf6a19SJiri Olsa if (invoke_bpf_mod_ret(m, &prog, fmod_ret, regs_off,
2507e384c7b7SKui-Feng Lee run_ctx_off, branches)) {
2508ae240823SKP Singh ret = -EINVAL;
2509ae240823SKP Singh goto cleanup;
2510ae240823SKP Singh }
2511ae240823SKP Singh }
2512ae240823SKP Singh
2513fec56f58SAlexei Starovoitov if (flags & BPF_TRAMP_F_CALL_ORIG) {
2514473e3150SMenglong Dong restore_regs(m, &prog, regs_off);
2515473e3150SMenglong Dong save_args(m, &prog, arg_stack_off, true);
2516fec56f58SAlexei Starovoitov
25178f873cc3SLeon Hwang if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
25188f873cc3SLeon Hwang /* Before calling the original function, restore the
25198f873cc3SLeon Hwang * tail_call_cnt from stack to rax.
25208f873cc3SLeon Hwang */
25218f873cc3SLeon Hwang RESTORE_TAIL_CALL_CNT(stack_size);
25228f873cc3SLeon Hwang
2523316cba62SJiri Olsa if (flags & BPF_TRAMP_F_ORIG_STACK) {
25248f873cc3SLeon Hwang emit_ldx(&prog, BPF_DW, BPF_REG_6, BPF_REG_FP, 8);
25258f873cc3SLeon Hwang EMIT2(0xff, 0xd3); /* call *rbx */
2526316cba62SJiri Olsa } else {
2527fec56f58SAlexei Starovoitov /* call original function */
2528b2e9dfe5SThomas Gleixner if (emit_rsb_call(&prog, orig_call, prog)) {
2529ae240823SKP Singh ret = -EINVAL;
2530ae240823SKP Singh goto cleanup;
2531ae240823SKP Singh }
2532316cba62SJiri Olsa }
2533fec56f58SAlexei Starovoitov /* remember return value in a stack for bpf prog to access */
2534fec56f58SAlexei Starovoitov emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
2535e21aa341SAlexei Starovoitov im->ip_after_call = prog;
2536b1f480bcSIngo Molnar memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
2537b9082970SStanislav Fomichev prog += X86_PATCH_SIZE;
2538fec56f58SAlexei Starovoitov }
2539fec56f58SAlexei Starovoitov
2540f7e0beafSKui-Feng Lee if (fmod_ret->nr_links) {
2541ae240823SKP Singh /* From Intel 64 and IA-32 Architectures Optimization
2542ae240823SKP Singh * Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler
2543ae240823SKP Singh * Coding Rule 11: All branch targets should be 16-byte
2544ae240823SKP Singh * aligned.
2545ae240823SKP Singh */
2546ae240823SKP Singh emit_align(&prog, 16);
2547ae240823SKP Singh /* Update the branches saved in invoke_bpf_mod_ret with the
2548ae240823SKP Singh * aligned address of do_fexit.
2549ae240823SKP Singh */
2550f7e0beafSKui-Feng Lee for (i = 0; i < fmod_ret->nr_links; i++)
2551ae240823SKP Singh emit_cond_near_jump(&branches[i], prog, branches[i],
2552ae240823SKP Singh X86_JNE);
2553ae240823SKP Singh }
2554ae240823SKP Singh
2555f7e0beafSKui-Feng Lee if (fexit->nr_links)
2556e384c7b7SKui-Feng Lee if (invoke_bpf(m, &prog, fexit, regs_off, run_ctx_off, false)) {
2557ae240823SKP Singh ret = -EINVAL;
2558ae240823SKP Singh goto cleanup;
2559ae240823SKP Singh }
2560fec56f58SAlexei Starovoitov
2561fec56f58SAlexei Starovoitov if (flags & BPF_TRAMP_F_RESTORE_REGS)
2562473e3150SMenglong Dong restore_regs(m, &prog, regs_off);
2563fec56f58SAlexei Starovoitov
2564ae240823SKP Singh /* This needs to be done regardless. If there were fmod_ret programs,
2565ae240823SKP Singh * the return value is only updated on the stack and still needs to be
2566ae240823SKP Singh * restored to R0.
2567ae240823SKP Singh */
2568e21aa341SAlexei Starovoitov if (flags & BPF_TRAMP_F_CALL_ORIG) {
2569e21aa341SAlexei Starovoitov im->ip_epilogue = prog;
2570e21aa341SAlexei Starovoitov /* arg1: mov rdi, im */
2571e21aa341SAlexei Starovoitov emit_mov_imm64(&prog, BPF_REG_1, (long) im >> 32, (u32) (long) im);
2572b2e9dfe5SThomas Gleixner if (emit_rsb_call(&prog, __bpf_tramp_exit, prog)) {
2573e21aa341SAlexei Starovoitov ret = -EINVAL;
2574e21aa341SAlexei Starovoitov goto cleanup;
2575e21aa341SAlexei Starovoitov }
25768f873cc3SLeon Hwang } else if (flags & BPF_TRAMP_F_TAIL_CALL_CTX)
25778f873cc3SLeon Hwang /* Before running the original function, restore the
25788f873cc3SLeon Hwang * tail_call_cnt from stack to rax.
25798f873cc3SLeon Hwang */
25808f873cc3SLeon Hwang RESTORE_TAIL_CALL_CNT(stack_size);
25818f873cc3SLeon Hwang
2582356ed649SHou Tao /* restore return value of orig_call or fentry prog back into RAX */
2583356ed649SHou Tao if (save_ret)
2584356ed649SHou Tao emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, -8);
2585fec56f58SAlexei Starovoitov
2586473e3150SMenglong Dong emit_ldx(&prog, BPF_DW, BPF_REG_6, BPF_REG_FP, -rbx_off);
2587fec56f58SAlexei Starovoitov EMIT1(0xC9); /* leave */
2588fec56f58SAlexei Starovoitov if (flags & BPF_TRAMP_F_SKIP_FRAME)
2589fec56f58SAlexei Starovoitov /* skip our return address and return to parent */
2590fec56f58SAlexei Starovoitov EMIT4(0x48, 0x83, 0xC4, 8); /* add rsp, 8 */
2591d77cfe59SPeter Zijlstra emit_return(&prog, prog);
259285d33df3SMartin KaFai Lau /* Make sure the trampoline generation logic doesn't overflow */
2593ae240823SKP Singh if (WARN_ON_ONCE(prog > (u8 *)image_end - BPF_INSN_SAFETY)) {
2594ae240823SKP Singh ret = -EFAULT;
2595ae240823SKP Singh goto cleanup;
2596ae240823SKP Singh }
2597ae240823SKP Singh ret = prog - (u8 *)image;
2598ae240823SKP Singh
2599ae240823SKP Singh cleanup:
2600ae240823SKP Singh kfree(branches);
2601ae240823SKP Singh return ret;
2602fec56f58SAlexei Starovoitov }
2603fec56f58SAlexei Starovoitov
emit_bpf_dispatcher(u8 ** pprog,int a,int b,s64 * progs,u8 * image,u8 * buf)260419c02415SSong Liu static int emit_bpf_dispatcher(u8 **pprog, int a, int b, s64 *progs, u8 *image, u8 *buf)
260575ccbef6SBjörn Töpel {
26067e639208SKP Singh u8 *jg_reloc, *prog = *pprog;
2607ced50fc4SJiri Olsa int pivot, err, jg_bytes = 1;
260875ccbef6SBjörn Töpel s64 jg_offset;
260975ccbef6SBjörn Töpel
261075ccbef6SBjörn Töpel if (a == b) {
261175ccbef6SBjörn Töpel /* Leaf node of recursion, i.e. not a range of indices
261275ccbef6SBjörn Töpel * anymore.
261375ccbef6SBjörn Töpel */
261475ccbef6SBjörn Töpel EMIT1(add_1mod(0x48, BPF_REG_3)); /* cmp rdx,func */
261575ccbef6SBjörn Töpel if (!is_simm32(progs[a]))
261675ccbef6SBjörn Töpel return -1;
261775ccbef6SBjörn Töpel EMIT2_off32(0x81, add_1reg(0xF8, BPF_REG_3),
261875ccbef6SBjörn Töpel progs[a]);
261975ccbef6SBjörn Töpel err = emit_cond_near_jump(&prog, /* je func */
262019c02415SSong Liu (void *)progs[a], image + (prog - buf),
262175ccbef6SBjörn Töpel X86_JE);
262275ccbef6SBjörn Töpel if (err)
262375ccbef6SBjörn Töpel return err;
262475ccbef6SBjörn Töpel
262519c02415SSong Liu emit_indirect_jump(&prog, 2 /* rdx */, image + (prog - buf));
262675ccbef6SBjörn Töpel
262775ccbef6SBjörn Töpel *pprog = prog;
262875ccbef6SBjörn Töpel return 0;
262975ccbef6SBjörn Töpel }
263075ccbef6SBjörn Töpel
263175ccbef6SBjörn Töpel /* Not a leaf node, so we pivot, and recursively descend into
263275ccbef6SBjörn Töpel * the lower and upper ranges.
263375ccbef6SBjörn Töpel */
263475ccbef6SBjörn Töpel pivot = (b - a) / 2;
263575ccbef6SBjörn Töpel EMIT1(add_1mod(0x48, BPF_REG_3)); /* cmp rdx,func */
263675ccbef6SBjörn Töpel if (!is_simm32(progs[a + pivot]))
263775ccbef6SBjörn Töpel return -1;
263875ccbef6SBjörn Töpel EMIT2_off32(0x81, add_1reg(0xF8, BPF_REG_3), progs[a + pivot]);
263975ccbef6SBjörn Töpel
264075ccbef6SBjörn Töpel if (pivot > 2) { /* jg upper_part */
264175ccbef6SBjörn Töpel /* Require near jump. */
264275ccbef6SBjörn Töpel jg_bytes = 4;
264375ccbef6SBjörn Töpel EMIT2_off32(0x0F, X86_JG + 0x10, 0);
264475ccbef6SBjörn Töpel } else {
264575ccbef6SBjörn Töpel EMIT2(X86_JG, 0);
264675ccbef6SBjörn Töpel }
264775ccbef6SBjörn Töpel jg_reloc = prog;
264875ccbef6SBjörn Töpel
264975ccbef6SBjörn Töpel err = emit_bpf_dispatcher(&prog, a, a + pivot, /* emit lower_part */
265019c02415SSong Liu progs, image, buf);
265175ccbef6SBjörn Töpel if (err)
265275ccbef6SBjörn Töpel return err;
265375ccbef6SBjörn Töpel
2654116eb788SBjörn Töpel /* From Intel 64 and IA-32 Architectures Optimization
2655116eb788SBjörn Töpel * Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler
2656116eb788SBjörn Töpel * Coding Rule 11: All branch targets should be 16-byte
2657116eb788SBjörn Töpel * aligned.
2658116eb788SBjörn Töpel */
26597e639208SKP Singh emit_align(&prog, 16);
266075ccbef6SBjörn Töpel jg_offset = prog - jg_reloc;
266175ccbef6SBjörn Töpel emit_code(jg_reloc - jg_bytes, jg_offset, jg_bytes);
266275ccbef6SBjörn Töpel
266375ccbef6SBjörn Töpel err = emit_bpf_dispatcher(&prog, a + pivot + 1, /* emit upper_part */
266419c02415SSong Liu b, progs, image, buf);
266575ccbef6SBjörn Töpel if (err)
266675ccbef6SBjörn Töpel return err;
266775ccbef6SBjörn Töpel
266875ccbef6SBjörn Töpel *pprog = prog;
266975ccbef6SBjörn Töpel return 0;
267075ccbef6SBjörn Töpel }
267175ccbef6SBjörn Töpel
cmp_ips(const void * a,const void * b)267275ccbef6SBjörn Töpel static int cmp_ips(const void *a, const void *b)
267375ccbef6SBjörn Töpel {
267475ccbef6SBjörn Töpel const s64 *ipa = a;
267575ccbef6SBjörn Töpel const s64 *ipb = b;
267675ccbef6SBjörn Töpel
267775ccbef6SBjörn Töpel if (*ipa > *ipb)
267875ccbef6SBjörn Töpel return 1;
267975ccbef6SBjörn Töpel if (*ipa < *ipb)
268075ccbef6SBjörn Töpel return -1;
268175ccbef6SBjörn Töpel return 0;
268275ccbef6SBjörn Töpel }
268375ccbef6SBjörn Töpel
arch_prepare_bpf_dispatcher(void * image,void * buf,s64 * funcs,int num_funcs)268419c02415SSong Liu int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_funcs)
268575ccbef6SBjörn Töpel {
268619c02415SSong Liu u8 *prog = buf;
268775ccbef6SBjörn Töpel
268875ccbef6SBjörn Töpel sort(funcs, num_funcs, sizeof(funcs[0]), cmp_ips, NULL);
268919c02415SSong Liu return emit_bpf_dispatcher(&prog, 0, num_funcs - 1, funcs, image, buf);
269075ccbef6SBjörn Töpel }
269175ccbef6SBjörn Töpel
26921c2a088aSAlexei Starovoitov struct x64_jit_data {
26931022a549SSong Liu struct bpf_binary_header *rw_header;
26941c2a088aSAlexei Starovoitov struct bpf_binary_header *header;
26951c2a088aSAlexei Starovoitov int *addrs;
26961c2a088aSAlexei Starovoitov u8 *image;
26971c2a088aSAlexei Starovoitov int proglen;
26981c2a088aSAlexei Starovoitov struct jit_context ctx;
26991c2a088aSAlexei Starovoitov };
27001c2a088aSAlexei Starovoitov
270193c5aeccSGary Lin #define MAX_PASSES 20
270293c5aeccSGary Lin #define PADDING_PASSES (MAX_PASSES - 5)
270393c5aeccSGary Lin
bpf_int_jit_compile(struct bpf_prog * prog)2704d1c55ab5SDaniel Borkmann struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
270562258278SAlexei Starovoitov {
27061022a549SSong Liu struct bpf_binary_header *rw_header = NULL;
2707f3c2af7bSAlexei Starovoitov struct bpf_binary_header *header = NULL;
2708959a7579SDaniel Borkmann struct bpf_prog *tmp, *orig_prog = prog;
27091c2a088aSAlexei Starovoitov struct x64_jit_data *jit_data;
2710f3c2af7bSAlexei Starovoitov int proglen, oldproglen = 0;
2711f3c2af7bSAlexei Starovoitov struct jit_context ctx = {};
2712959a7579SDaniel Borkmann bool tmp_blinded = false;
27131c2a088aSAlexei Starovoitov bool extra_pass = false;
271493c5aeccSGary Lin bool padding = false;
27151022a549SSong Liu u8 *rw_image = NULL;
2716f3c2af7bSAlexei Starovoitov u8 *image = NULL;
2717f3c2af7bSAlexei Starovoitov int *addrs;
2718f3c2af7bSAlexei Starovoitov int pass;
2719f3c2af7bSAlexei Starovoitov int i;
2720f3c2af7bSAlexei Starovoitov
272160b58afcSAlexei Starovoitov if (!prog->jit_requested)
2722959a7579SDaniel Borkmann return orig_prog;
2723959a7579SDaniel Borkmann
2724959a7579SDaniel Borkmann tmp = bpf_jit_blind_constants(prog);
2725a2c7a983SIngo Molnar /*
2726a2c7a983SIngo Molnar * If blinding was requested and we failed during blinding,
2727959a7579SDaniel Borkmann * we must fall back to the interpreter.
2728959a7579SDaniel Borkmann */
2729959a7579SDaniel Borkmann if (IS_ERR(tmp))
2730959a7579SDaniel Borkmann return orig_prog;
2731959a7579SDaniel Borkmann if (tmp != prog) {
2732959a7579SDaniel Borkmann tmp_blinded = true;
2733959a7579SDaniel Borkmann prog = tmp;
2734959a7579SDaniel Borkmann }
2735f3c2af7bSAlexei Starovoitov
27361c2a088aSAlexei Starovoitov jit_data = prog->aux->jit_data;
27371c2a088aSAlexei Starovoitov if (!jit_data) {
27381c2a088aSAlexei Starovoitov jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
27391c2a088aSAlexei Starovoitov if (!jit_data) {
27401c2a088aSAlexei Starovoitov prog = orig_prog;
27411c2a088aSAlexei Starovoitov goto out;
27421c2a088aSAlexei Starovoitov }
27431c2a088aSAlexei Starovoitov prog->aux->jit_data = jit_data;
27441c2a088aSAlexei Starovoitov }
27451c2a088aSAlexei Starovoitov addrs = jit_data->addrs;
27461c2a088aSAlexei Starovoitov if (addrs) {
27471c2a088aSAlexei Starovoitov ctx = jit_data->ctx;
27481c2a088aSAlexei Starovoitov oldproglen = jit_data->proglen;
27491c2a088aSAlexei Starovoitov image = jit_data->image;
27501c2a088aSAlexei Starovoitov header = jit_data->header;
27511022a549SSong Liu rw_header = jit_data->rw_header;
27521022a549SSong Liu rw_image = (void *)rw_header + ((void *)image - (void *)header);
27531c2a088aSAlexei Starovoitov extra_pass = true;
275493c5aeccSGary Lin padding = true;
27551c2a088aSAlexei Starovoitov goto skip_init_addrs;
27561c2a088aSAlexei Starovoitov }
2757de920fc6SYonghong Song addrs = kvmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL);
2758959a7579SDaniel Borkmann if (!addrs) {
2759959a7579SDaniel Borkmann prog = orig_prog;
27601c2a088aSAlexei Starovoitov goto out_addrs;
2761959a7579SDaniel Borkmann }
2762f3c2af7bSAlexei Starovoitov
2763a2c7a983SIngo Molnar /*
2764a2c7a983SIngo Molnar * Before first pass, make a rough estimation of addrs[]
2765a2c7a983SIngo Molnar * each BPF instruction is translated to less than 64 bytes
2766f3c2af7bSAlexei Starovoitov */
27677c2e988fSAlexei Starovoitov for (proglen = 0, i = 0; i <= prog->len; i++) {
2768f3c2af7bSAlexei Starovoitov proglen += 64;
2769f3c2af7bSAlexei Starovoitov addrs[i] = proglen;
2770f3c2af7bSAlexei Starovoitov }
2771f3c2af7bSAlexei Starovoitov ctx.cleanup_addr = proglen;
27721c2a088aSAlexei Starovoitov skip_init_addrs:
2773f3c2af7bSAlexei Starovoitov
2774a2c7a983SIngo Molnar /*
2775a2c7a983SIngo Molnar * JITed image shrinks with every pass and the loop iterates
2776a2c7a983SIngo Molnar * until the image stops shrinking. Very large BPF programs
27773f7352bfSAlexei Starovoitov * may converge on the last pass. In such case do one more
2778a2c7a983SIngo Molnar * pass to emit the final image.
27793f7352bfSAlexei Starovoitov */
278093c5aeccSGary Lin for (pass = 0; pass < MAX_PASSES || image; pass++) {
278193c5aeccSGary Lin if (!padding && pass >= PADDING_PASSES)
278293c5aeccSGary Lin padding = true;
27831022a549SSong Liu proglen = do_jit(prog, addrs, image, rw_image, oldproglen, &ctx, padding);
2784f3c2af7bSAlexei Starovoitov if (proglen <= 0) {
27853aab8884SDaniel Borkmann out_image:
2786f3c2af7bSAlexei Starovoitov image = NULL;
2787676b2daaSSong Liu if (header) {
2788676b2daaSSong Liu bpf_arch_text_copy(&header->size, &rw_header->size,
2789676b2daaSSong Liu sizeof(rw_header->size));
27901022a549SSong Liu bpf_jit_binary_pack_free(header, rw_header);
2791676b2daaSSong Liu }
279273e14451SHou Tao /* Fall back to interpreter mode */
2793959a7579SDaniel Borkmann prog = orig_prog;
279473e14451SHou Tao if (extra_pass) {
279573e14451SHou Tao prog->bpf_func = NULL;
279673e14451SHou Tao prog->jited = 0;
279773e14451SHou Tao prog->jited_len = 0;
279873e14451SHou Tao }
2799959a7579SDaniel Borkmann goto out_addrs;
2800f3c2af7bSAlexei Starovoitov }
28010a14842fSEric Dumazet if (image) {
2802e0ee9c12SAlexei Starovoitov if (proglen != oldproglen) {
2803f3c2af7bSAlexei Starovoitov pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
2804f3c2af7bSAlexei Starovoitov proglen, oldproglen);
28053aab8884SDaniel Borkmann goto out_image;
2806e0ee9c12SAlexei Starovoitov }
28070a14842fSEric Dumazet break;
28080a14842fSEric Dumazet }
28090a14842fSEric Dumazet if (proglen == oldproglen) {
28103dec541bSAlexei Starovoitov /*
28113dec541bSAlexei Starovoitov * The number of entries in extable is the number of BPF_LDX
28123dec541bSAlexei Starovoitov * insns that access kernel memory via "pointer to BTF type".
28133dec541bSAlexei Starovoitov * The verifier changed their opcode from LDX|MEM|size
28143dec541bSAlexei Starovoitov * to LDX|PROBE_MEM|size to make JITing easier.
28153dec541bSAlexei Starovoitov */
28163dec541bSAlexei Starovoitov u32 align = __alignof__(struct exception_table_entry);
28173dec541bSAlexei Starovoitov u32 extable_size = prog->aux->num_exentries *
28183dec541bSAlexei Starovoitov sizeof(struct exception_table_entry);
28193dec541bSAlexei Starovoitov
28203dec541bSAlexei Starovoitov /* allocate module memory for x86 insns and extable */
28211022a549SSong Liu header = bpf_jit_binary_pack_alloc(roundup(proglen, align) + extable_size,
28221022a549SSong Liu &image, align, &rw_header, &rw_image,
28231022a549SSong Liu jit_fill_hole);
2824959a7579SDaniel Borkmann if (!header) {
2825959a7579SDaniel Borkmann prog = orig_prog;
2826959a7579SDaniel Borkmann goto out_addrs;
2827959a7579SDaniel Borkmann }
28283dec541bSAlexei Starovoitov prog->aux->extable = (void *) image + roundup(proglen, align);
28290a14842fSEric Dumazet }
28300a14842fSEric Dumazet oldproglen = proglen;
28316007b080SDaniel Borkmann cond_resched();
28320a14842fSEric Dumazet }
283379617801SDaniel Borkmann
28340a14842fSEric Dumazet if (bpf_jit_enable > 1)
2835ad96f1c9SYonghong Song bpf_jit_dump(prog->len, proglen, pass + 1, rw_image);
28360a14842fSEric Dumazet
28370a14842fSEric Dumazet if (image) {
28381c2a088aSAlexei Starovoitov if (!prog->is_func || extra_pass) {
28391022a549SSong Liu /*
28401022a549SSong Liu * bpf_jit_binary_pack_finalize fails in two scenarios:
28411022a549SSong Liu * 1) header is not pointing to proper module memory;
28421022a549SSong Liu * 2) the arch doesn't support bpf_arch_text_copy().
28431022a549SSong Liu *
2844f95f768fSSong Liu * Both cases are serious bugs and justify WARN_ON.
28451022a549SSong Liu */
2846f95f768fSSong Liu if (WARN_ON(bpf_jit_binary_pack_finalize(prog, header, rw_header))) {
284773e14451SHou Tao /* header has been freed */
284873e14451SHou Tao header = NULL;
284973e14451SHou Tao goto out_image;
2850f95f768fSSong Liu }
2851f95f768fSSong Liu
2852428d5df1SDaniel Borkmann bpf_tail_call_direct_fixup(prog);
28531c2a088aSAlexei Starovoitov } else {
28541c2a088aSAlexei Starovoitov jit_data->addrs = addrs;
28551c2a088aSAlexei Starovoitov jit_data->ctx = ctx;
28561c2a088aSAlexei Starovoitov jit_data->proglen = proglen;
28571c2a088aSAlexei Starovoitov jit_data->image = image;
28581c2a088aSAlexei Starovoitov jit_data->header = header;
28591022a549SSong Liu jit_data->rw_header = rw_header;
28601c2a088aSAlexei Starovoitov }
2861f3c2af7bSAlexei Starovoitov prog->bpf_func = (void *)image;
2862a91263d5SDaniel Borkmann prog->jited = 1;
2863783d28ddSMartin KaFai Lau prog->jited_len = proglen;
28649d5ecb09SDaniel Borkmann } else {
28659d5ecb09SDaniel Borkmann prog = orig_prog;
28660a14842fSEric Dumazet }
2867959a7579SDaniel Borkmann
286839f56ca9SDaniel Borkmann if (!image || !prog->is_func || extra_pass) {
2869c454a46bSMartin KaFai Lau if (image)
28707c2e988fSAlexei Starovoitov bpf_prog_fill_jited_linfo(prog, addrs + 1);
2871959a7579SDaniel Borkmann out_addrs:
2872de920fc6SYonghong Song kvfree(addrs);
28731c2a088aSAlexei Starovoitov kfree(jit_data);
28741c2a088aSAlexei Starovoitov prog->aux->jit_data = NULL;
28751c2a088aSAlexei Starovoitov }
2876959a7579SDaniel Borkmann out:
2877959a7579SDaniel Borkmann if (tmp_blinded)
2878959a7579SDaniel Borkmann bpf_jit_prog_release_other(prog, prog == orig_prog ?
2879959a7579SDaniel Borkmann tmp : orig_prog);
2880d1c55ab5SDaniel Borkmann return prog;
28810a14842fSEric Dumazet }
2882e6ac2450SMartin KaFai Lau
bpf_jit_supports_kfunc_call(void)2883e6ac2450SMartin KaFai Lau bool bpf_jit_supports_kfunc_call(void)
2884e6ac2450SMartin KaFai Lau {
2885e6ac2450SMartin KaFai Lau return true;
2886e6ac2450SMartin KaFai Lau }
2887ebc1415dSSong Liu
bpf_arch_text_copy(void * dst,void * src,size_t len)2888ebc1415dSSong Liu void *bpf_arch_text_copy(void *dst, void *src, size_t len)
2889ebc1415dSSong Liu {
2890ebc1415dSSong Liu if (text_poke_copy(dst, src, len) == NULL)
2891ebc1415dSSong Liu return ERR_PTR(-EINVAL);
2892ebc1415dSSong Liu return dst;
2893ebc1415dSSong Liu }
289495acd881STony Ambardar
289595acd881STony Ambardar /* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
bpf_jit_supports_subprog_tailcalls(void)289695acd881STony Ambardar bool bpf_jit_supports_subprog_tailcalls(void)
289795acd881STony Ambardar {
289895acd881STony Ambardar return true;
289995acd881STony Ambardar }
29001d5f82d9SSong Liu
bpf_jit_free(struct bpf_prog * prog)29011d5f82d9SSong Liu void bpf_jit_free(struct bpf_prog *prog)
29021d5f82d9SSong Liu {
29031d5f82d9SSong Liu if (prog->jited) {
29041d5f82d9SSong Liu struct x64_jit_data *jit_data = prog->aux->jit_data;
29051d5f82d9SSong Liu struct bpf_binary_header *hdr;
29061d5f82d9SSong Liu
29071d5f82d9SSong Liu /*
29081d5f82d9SSong Liu * If we fail the final pass of JIT (from jit_subprogs),
29091d5f82d9SSong Liu * the program may not be finalized yet. Call finalize here
29101d5f82d9SSong Liu * before freeing it.
29111d5f82d9SSong Liu */
29121d5f82d9SSong Liu if (jit_data) {
29131d5f82d9SSong Liu bpf_jit_binary_pack_finalize(prog, jit_data->header,
29141d5f82d9SSong Liu jit_data->rw_header);
29151d5f82d9SSong Liu kvfree(jit_data->addrs);
29161d5f82d9SSong Liu kfree(jit_data);
29171d5f82d9SSong Liu }
29181d5f82d9SSong Liu hdr = bpf_jit_binary_pack_hdr(prog);
29191d5f82d9SSong Liu bpf_jit_binary_pack_free(hdr, NULL);
29201d5f82d9SSong Liu WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(prog));
29211d5f82d9SSong Liu }
29221d5f82d9SSong Liu
29231d5f82d9SSong Liu bpf_prog_unlock_free(prog);
29241d5f82d9SSong Liu }
2925f64b2dc8SJiri Olsa
bpf_arch_poke_desc_update(struct bpf_jit_poke_descriptor * poke,struct bpf_prog * new,struct bpf_prog * old)2926f64b2dc8SJiri Olsa void bpf_arch_poke_desc_update(struct bpf_jit_poke_descriptor *poke,
2927f64b2dc8SJiri Olsa struct bpf_prog *new, struct bpf_prog *old)
2928f64b2dc8SJiri Olsa {
2929f64b2dc8SJiri Olsa u8 *old_addr, *new_addr, *old_bypass_addr;
2930f64b2dc8SJiri Olsa int ret;
2931f64b2dc8SJiri Olsa
2932f64b2dc8SJiri Olsa old_bypass_addr = old ? NULL : poke->bypass_addr;
2933f64b2dc8SJiri Olsa old_addr = old ? (u8 *)old->bpf_func + poke->adj_off : NULL;
2934f64b2dc8SJiri Olsa new_addr = new ? (u8 *)new->bpf_func + poke->adj_off : NULL;
2935f64b2dc8SJiri Olsa
2936f64b2dc8SJiri Olsa /*
2937f64b2dc8SJiri Olsa * On program loading or teardown, the program's kallsym entry
2938f64b2dc8SJiri Olsa * might not be in place, so we use __bpf_arch_text_poke to skip
2939f64b2dc8SJiri Olsa * the kallsyms check.
2940f64b2dc8SJiri Olsa */
2941f64b2dc8SJiri Olsa if (new) {
2942f64b2dc8SJiri Olsa ret = __bpf_arch_text_poke(poke->tailcall_target,
2943f64b2dc8SJiri Olsa BPF_MOD_JUMP,
2944f64b2dc8SJiri Olsa old_addr, new_addr);
2945f64b2dc8SJiri Olsa BUG_ON(ret < 0);
2946f64b2dc8SJiri Olsa if (!old) {
2947f64b2dc8SJiri Olsa ret = __bpf_arch_text_poke(poke->tailcall_bypass,
2948f64b2dc8SJiri Olsa BPF_MOD_JUMP,
2949f64b2dc8SJiri Olsa poke->bypass_addr,
2950f64b2dc8SJiri Olsa NULL);
2951f64b2dc8SJiri Olsa BUG_ON(ret < 0);
2952f64b2dc8SJiri Olsa }
2953f64b2dc8SJiri Olsa } else {
2954f64b2dc8SJiri Olsa ret = __bpf_arch_text_poke(poke->tailcall_bypass,
2955f64b2dc8SJiri Olsa BPF_MOD_JUMP,
2956f64b2dc8SJiri Olsa old_bypass_addr,
2957f64b2dc8SJiri Olsa poke->bypass_addr);
2958f64b2dc8SJiri Olsa BUG_ON(ret < 0);
2959f64b2dc8SJiri Olsa /* let other CPUs finish the execution of program
2960f64b2dc8SJiri Olsa * so that it will not possible to expose them
2961f64b2dc8SJiri Olsa * to invalid nop, stack unwind, nop state
2962f64b2dc8SJiri Olsa */
2963f64b2dc8SJiri Olsa if (!ret)
2964f64b2dc8SJiri Olsa synchronize_rcu();
2965f64b2dc8SJiri Olsa ret = __bpf_arch_text_poke(poke->tailcall_target,
2966f64b2dc8SJiri Olsa BPF_MOD_JUMP,
2967f64b2dc8SJiri Olsa old_addr, NULL);
2968f64b2dc8SJiri Olsa BUG_ON(ret < 0);
2969f64b2dc8SJiri Olsa }
2970f64b2dc8SJiri Olsa }
2971