1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * BPF JIT compiler for RV32G
4 *
5 * Copyright (c) 2020 Luke Nelson <luke.r.nels@gmail.com>
6 * Copyright (c) 2020 Xi Wang <xi.wang@gmail.com>
7 *
8 * The code is based on the BPF JIT compiler for RV64G by Björn Töpel and
9 * the BPF JIT compiler for 32-bit ARM by Shubham Bansal and Mircea Gherzan.
10 */
11
12 #include <linux/bpf.h>
13 #include <linux/filter.h>
14 #include "bpf_jit.h"
15
16 /*
17 * Stack layout during BPF program execution:
18 *
19 * high
20 * RV32 fp => +----------+
21 * | saved ra |
22 * | saved fp | RV32 callee-saved registers
23 * | ... |
24 * +----------+ <= (fp - 4 * NR_SAVED_REGISTERS)
25 * | hi(R6) |
26 * | lo(R6) |
27 * | hi(R7) | JIT scratch space for BPF registers
28 * | lo(R7) |
29 * | ... |
30 * BPF_REG_FP => +----------+ <= (fp - 4 * NR_SAVED_REGISTERS
31 * | | - 4 * BPF_JIT_SCRATCH_REGS)
32 * | |
33 * | ... | BPF program stack
34 * | |
35 * RV32 sp => +----------+
36 * | |
37 * | ... | Function call stack
38 * | |
39 * +----------+
40 * low
41 */
42
43 enum {
44 /* Stack layout - these are offsets from top of JIT scratch space. */
45 BPF_R6_HI,
46 BPF_R6_LO,
47 BPF_R7_HI,
48 BPF_R7_LO,
49 BPF_R8_HI,
50 BPF_R8_LO,
51 BPF_R9_HI,
52 BPF_R9_LO,
53 BPF_AX_HI,
54 BPF_AX_LO,
55 /* Stack space for BPF_REG_6 through BPF_REG_9 and BPF_REG_AX. */
56 BPF_JIT_SCRATCH_REGS,
57 };
58
59 /* Number of callee-saved registers stored to stack: ra, fp, s1--s7. */
60 #define NR_SAVED_REGISTERS 9
61
62 /* Offset from fp for BPF registers stored on stack. */
63 #define STACK_OFFSET(k) (-4 - (4 * NR_SAVED_REGISTERS) - (4 * (k)))
64
65 #define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
66 #define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
67
68 #define RV_REG_TCC RV_REG_T6
69 #define RV_REG_TCC_SAVED RV_REG_S7
70
71 static const s8 bpf2rv32[][2] = {
72 /* Return value from in-kernel function, and exit value from eBPF. */
73 [BPF_REG_0] = {RV_REG_S2, RV_REG_S1},
74 /* Arguments from eBPF program to in-kernel function. */
75 [BPF_REG_1] = {RV_REG_A1, RV_REG_A0},
76 [BPF_REG_2] = {RV_REG_A3, RV_REG_A2},
77 [BPF_REG_3] = {RV_REG_A5, RV_REG_A4},
78 [BPF_REG_4] = {RV_REG_A7, RV_REG_A6},
79 [BPF_REG_5] = {RV_REG_S4, RV_REG_S3},
80 /*
81 * Callee-saved registers that in-kernel function will preserve.
82 * Stored on the stack.
83 */
84 [BPF_REG_6] = {STACK_OFFSET(BPF_R6_HI), STACK_OFFSET(BPF_R6_LO)},
85 [BPF_REG_7] = {STACK_OFFSET(BPF_R7_HI), STACK_OFFSET(BPF_R7_LO)},
86 [BPF_REG_8] = {STACK_OFFSET(BPF_R8_HI), STACK_OFFSET(BPF_R8_LO)},
87 [BPF_REG_9] = {STACK_OFFSET(BPF_R9_HI), STACK_OFFSET(BPF_R9_LO)},
88 /* Read-only frame pointer to access BPF stack. */
89 [BPF_REG_FP] = {RV_REG_S6, RV_REG_S5},
90 /* Temporary register for blinding constants. Stored on the stack. */
91 [BPF_REG_AX] = {STACK_OFFSET(BPF_AX_HI), STACK_OFFSET(BPF_AX_LO)},
92 /*
93 * Temporary registers used by the JIT to operate on registers stored
94 * on the stack. Save t0 and t1 to be used as temporaries in generated
95 * code.
96 */
97 [TMP_REG_1] = {RV_REG_T3, RV_REG_T2},
98 [TMP_REG_2] = {RV_REG_T5, RV_REG_T4},
99 };
100
hi(const s8 * r)101 static s8 hi(const s8 *r)
102 {
103 return r[0];
104 }
105
lo(const s8 * r)106 static s8 lo(const s8 *r)
107 {
108 return r[1];
109 }
110
emit_imm(const s8 rd,s32 imm,struct rv_jit_context * ctx)111 static void emit_imm(const s8 rd, s32 imm, struct rv_jit_context *ctx)
112 {
113 u32 upper = (imm + (1 << 11)) >> 12;
114 u32 lower = imm & 0xfff;
115
116 if (upper) {
117 emit(rv_lui(rd, upper), ctx);
118 emit(rv_addi(rd, rd, lower), ctx);
119 } else {
120 emit(rv_addi(rd, RV_REG_ZERO, lower), ctx);
121 }
122 }
123
emit_imm32(const s8 * rd,s32 imm,struct rv_jit_context * ctx)124 static void emit_imm32(const s8 *rd, s32 imm, struct rv_jit_context *ctx)
125 {
126 /* Emit immediate into lower bits. */
127 emit_imm(lo(rd), imm, ctx);
128
129 /* Sign-extend into upper bits. */
130 if (imm >= 0)
131 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
132 else
133 emit(rv_addi(hi(rd), RV_REG_ZERO, -1), ctx);
134 }
135
emit_imm64(const s8 * rd,s32 imm_hi,s32 imm_lo,struct rv_jit_context * ctx)136 static void emit_imm64(const s8 *rd, s32 imm_hi, s32 imm_lo,
137 struct rv_jit_context *ctx)
138 {
139 emit_imm(lo(rd), imm_lo, ctx);
140 emit_imm(hi(rd), imm_hi, ctx);
141 }
142
__build_epilogue(bool is_tail_call,struct rv_jit_context * ctx)143 static void __build_epilogue(bool is_tail_call, struct rv_jit_context *ctx)
144 {
145 int stack_adjust = ctx->stack_size;
146 const s8 *r0 = bpf2rv32[BPF_REG_0];
147
148 /* Set return value if not tail call. */
149 if (!is_tail_call) {
150 emit(rv_addi(RV_REG_A0, lo(r0), 0), ctx);
151 emit(rv_addi(RV_REG_A1, hi(r0), 0), ctx);
152 }
153
154 /* Restore callee-saved registers. */
155 emit(rv_lw(RV_REG_RA, stack_adjust - 4, RV_REG_SP), ctx);
156 emit(rv_lw(RV_REG_FP, stack_adjust - 8, RV_REG_SP), ctx);
157 emit(rv_lw(RV_REG_S1, stack_adjust - 12, RV_REG_SP), ctx);
158 emit(rv_lw(RV_REG_S2, stack_adjust - 16, RV_REG_SP), ctx);
159 emit(rv_lw(RV_REG_S3, stack_adjust - 20, RV_REG_SP), ctx);
160 emit(rv_lw(RV_REG_S4, stack_adjust - 24, RV_REG_SP), ctx);
161 emit(rv_lw(RV_REG_S5, stack_adjust - 28, RV_REG_SP), ctx);
162 emit(rv_lw(RV_REG_S6, stack_adjust - 32, RV_REG_SP), ctx);
163 emit(rv_lw(RV_REG_S7, stack_adjust - 36, RV_REG_SP), ctx);
164
165 emit(rv_addi(RV_REG_SP, RV_REG_SP, stack_adjust), ctx);
166
167 if (is_tail_call) {
168 /*
169 * goto *(t0 + 4);
170 * Skips first instruction of prologue which initializes tail
171 * call counter. Assumes t0 contains address of target program,
172 * see emit_bpf_tail_call.
173 */
174 emit(rv_jalr(RV_REG_ZERO, RV_REG_T0, 4), ctx);
175 } else {
176 emit(rv_jalr(RV_REG_ZERO, RV_REG_RA, 0), ctx);
177 }
178 }
179
is_stacked(s8 reg)180 static bool is_stacked(s8 reg)
181 {
182 return reg < 0;
183 }
184
bpf_get_reg64(const s8 * reg,const s8 * tmp,struct rv_jit_context * ctx)185 static const s8 *bpf_get_reg64(const s8 *reg, const s8 *tmp,
186 struct rv_jit_context *ctx)
187 {
188 if (is_stacked(hi(reg))) {
189 emit(rv_lw(hi(tmp), hi(reg), RV_REG_FP), ctx);
190 emit(rv_lw(lo(tmp), lo(reg), RV_REG_FP), ctx);
191 reg = tmp;
192 }
193 return reg;
194 }
195
bpf_put_reg64(const s8 * reg,const s8 * src,struct rv_jit_context * ctx)196 static void bpf_put_reg64(const s8 *reg, const s8 *src,
197 struct rv_jit_context *ctx)
198 {
199 if (is_stacked(hi(reg))) {
200 emit(rv_sw(RV_REG_FP, hi(reg), hi(src)), ctx);
201 emit(rv_sw(RV_REG_FP, lo(reg), lo(src)), ctx);
202 }
203 }
204
bpf_get_reg32(const s8 * reg,const s8 * tmp,struct rv_jit_context * ctx)205 static const s8 *bpf_get_reg32(const s8 *reg, const s8 *tmp,
206 struct rv_jit_context *ctx)
207 {
208 if (is_stacked(lo(reg))) {
209 emit(rv_lw(lo(tmp), lo(reg), RV_REG_FP), ctx);
210 reg = tmp;
211 }
212 return reg;
213 }
214
bpf_put_reg32(const s8 * reg,const s8 * src,struct rv_jit_context * ctx)215 static void bpf_put_reg32(const s8 *reg, const s8 *src,
216 struct rv_jit_context *ctx)
217 {
218 if (is_stacked(lo(reg))) {
219 emit(rv_sw(RV_REG_FP, lo(reg), lo(src)), ctx);
220 if (!ctx->prog->aux->verifier_zext)
221 emit(rv_sw(RV_REG_FP, hi(reg), RV_REG_ZERO), ctx);
222 } else if (!ctx->prog->aux->verifier_zext) {
223 emit(rv_addi(hi(reg), RV_REG_ZERO, 0), ctx);
224 }
225 }
226
emit_jump_and_link(u8 rd,s32 rvoff,bool force_jalr,struct rv_jit_context * ctx)227 static void emit_jump_and_link(u8 rd, s32 rvoff, bool force_jalr,
228 struct rv_jit_context *ctx)
229 {
230 s32 upper, lower;
231
232 if (rvoff && is_21b_int(rvoff) && !force_jalr) {
233 emit(rv_jal(rd, rvoff >> 1), ctx);
234 return;
235 }
236
237 upper = (rvoff + (1 << 11)) >> 12;
238 lower = rvoff & 0xfff;
239 emit(rv_auipc(RV_REG_T1, upper), ctx);
240 emit(rv_jalr(rd, RV_REG_T1, lower), ctx);
241 }
242
emit_alu_i64(const s8 * dst,s32 imm,struct rv_jit_context * ctx,const u8 op)243 static void emit_alu_i64(const s8 *dst, s32 imm,
244 struct rv_jit_context *ctx, const u8 op)
245 {
246 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
247 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
248
249 switch (op) {
250 case BPF_MOV:
251 emit_imm32(rd, imm, ctx);
252 break;
253 case BPF_AND:
254 if (is_12b_int(imm)) {
255 emit(rv_andi(lo(rd), lo(rd), imm), ctx);
256 } else {
257 emit_imm(RV_REG_T0, imm, ctx);
258 emit(rv_and(lo(rd), lo(rd), RV_REG_T0), ctx);
259 }
260 if (imm >= 0)
261 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
262 break;
263 case BPF_OR:
264 if (is_12b_int(imm)) {
265 emit(rv_ori(lo(rd), lo(rd), imm), ctx);
266 } else {
267 emit_imm(RV_REG_T0, imm, ctx);
268 emit(rv_or(lo(rd), lo(rd), RV_REG_T0), ctx);
269 }
270 if (imm < 0)
271 emit(rv_ori(hi(rd), RV_REG_ZERO, -1), ctx);
272 break;
273 case BPF_XOR:
274 if (is_12b_int(imm)) {
275 emit(rv_xori(lo(rd), lo(rd), imm), ctx);
276 } else {
277 emit_imm(RV_REG_T0, imm, ctx);
278 emit(rv_xor(lo(rd), lo(rd), RV_REG_T0), ctx);
279 }
280 if (imm < 0)
281 emit(rv_xori(hi(rd), hi(rd), -1), ctx);
282 break;
283 case BPF_LSH:
284 if (imm >= 32) {
285 emit(rv_slli(hi(rd), lo(rd), imm - 32), ctx);
286 emit(rv_addi(lo(rd), RV_REG_ZERO, 0), ctx);
287 } else if (imm == 0) {
288 /* Do nothing. */
289 } else {
290 emit(rv_srli(RV_REG_T0, lo(rd), 32 - imm), ctx);
291 emit(rv_slli(hi(rd), hi(rd), imm), ctx);
292 emit(rv_or(hi(rd), RV_REG_T0, hi(rd)), ctx);
293 emit(rv_slli(lo(rd), lo(rd), imm), ctx);
294 }
295 break;
296 case BPF_RSH:
297 if (imm >= 32) {
298 emit(rv_srli(lo(rd), hi(rd), imm - 32), ctx);
299 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
300 } else if (imm == 0) {
301 /* Do nothing. */
302 } else {
303 emit(rv_slli(RV_REG_T0, hi(rd), 32 - imm), ctx);
304 emit(rv_srli(lo(rd), lo(rd), imm), ctx);
305 emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
306 emit(rv_srli(hi(rd), hi(rd), imm), ctx);
307 }
308 break;
309 case BPF_ARSH:
310 if (imm >= 32) {
311 emit(rv_srai(lo(rd), hi(rd), imm - 32), ctx);
312 emit(rv_srai(hi(rd), hi(rd), 31), ctx);
313 } else if (imm == 0) {
314 /* Do nothing. */
315 } else {
316 emit(rv_slli(RV_REG_T0, hi(rd), 32 - imm), ctx);
317 emit(rv_srli(lo(rd), lo(rd), imm), ctx);
318 emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
319 emit(rv_srai(hi(rd), hi(rd), imm), ctx);
320 }
321 break;
322 }
323
324 bpf_put_reg64(dst, rd, ctx);
325 }
326
emit_alu_i32(const s8 * dst,s32 imm,struct rv_jit_context * ctx,const u8 op)327 static void emit_alu_i32(const s8 *dst, s32 imm,
328 struct rv_jit_context *ctx, const u8 op)
329 {
330 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
331 const s8 *rd = bpf_get_reg32(dst, tmp1, ctx);
332
333 switch (op) {
334 case BPF_MOV:
335 emit_imm(lo(rd), imm, ctx);
336 break;
337 case BPF_ADD:
338 if (is_12b_int(imm)) {
339 emit(rv_addi(lo(rd), lo(rd), imm), ctx);
340 } else {
341 emit_imm(RV_REG_T0, imm, ctx);
342 emit(rv_add(lo(rd), lo(rd), RV_REG_T0), ctx);
343 }
344 break;
345 case BPF_SUB:
346 if (is_12b_int(-imm)) {
347 emit(rv_addi(lo(rd), lo(rd), -imm), ctx);
348 } else {
349 emit_imm(RV_REG_T0, imm, ctx);
350 emit(rv_sub(lo(rd), lo(rd), RV_REG_T0), ctx);
351 }
352 break;
353 case BPF_AND:
354 if (is_12b_int(imm)) {
355 emit(rv_andi(lo(rd), lo(rd), imm), ctx);
356 } else {
357 emit_imm(RV_REG_T0, imm, ctx);
358 emit(rv_and(lo(rd), lo(rd), RV_REG_T0), ctx);
359 }
360 break;
361 case BPF_OR:
362 if (is_12b_int(imm)) {
363 emit(rv_ori(lo(rd), lo(rd), imm), ctx);
364 } else {
365 emit_imm(RV_REG_T0, imm, ctx);
366 emit(rv_or(lo(rd), lo(rd), RV_REG_T0), ctx);
367 }
368 break;
369 case BPF_XOR:
370 if (is_12b_int(imm)) {
371 emit(rv_xori(lo(rd), lo(rd), imm), ctx);
372 } else {
373 emit_imm(RV_REG_T0, imm, ctx);
374 emit(rv_xor(lo(rd), lo(rd), RV_REG_T0), ctx);
375 }
376 break;
377 case BPF_LSH:
378 if (is_12b_int(imm)) {
379 emit(rv_slli(lo(rd), lo(rd), imm), ctx);
380 } else {
381 emit_imm(RV_REG_T0, imm, ctx);
382 emit(rv_sll(lo(rd), lo(rd), RV_REG_T0), ctx);
383 }
384 break;
385 case BPF_RSH:
386 if (is_12b_int(imm)) {
387 emit(rv_srli(lo(rd), lo(rd), imm), ctx);
388 } else {
389 emit_imm(RV_REG_T0, imm, ctx);
390 emit(rv_srl(lo(rd), lo(rd), RV_REG_T0), ctx);
391 }
392 break;
393 case BPF_ARSH:
394 if (is_12b_int(imm)) {
395 emit(rv_srai(lo(rd), lo(rd), imm), ctx);
396 } else {
397 emit_imm(RV_REG_T0, imm, ctx);
398 emit(rv_sra(lo(rd), lo(rd), RV_REG_T0), ctx);
399 }
400 break;
401 }
402
403 bpf_put_reg32(dst, rd, ctx);
404 }
405
emit_alu_r64(const s8 * dst,const s8 * src,struct rv_jit_context * ctx,const u8 op)406 static void emit_alu_r64(const s8 *dst, const s8 *src,
407 struct rv_jit_context *ctx, const u8 op)
408 {
409 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
410 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
411 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
412 const s8 *rs = bpf_get_reg64(src, tmp2, ctx);
413
414 switch (op) {
415 case BPF_MOV:
416 emit(rv_addi(lo(rd), lo(rs), 0), ctx);
417 emit(rv_addi(hi(rd), hi(rs), 0), ctx);
418 break;
419 case BPF_ADD:
420 if (rd == rs) {
421 emit(rv_srli(RV_REG_T0, lo(rd), 31), ctx);
422 emit(rv_slli(hi(rd), hi(rd), 1), ctx);
423 emit(rv_or(hi(rd), RV_REG_T0, hi(rd)), ctx);
424 emit(rv_slli(lo(rd), lo(rd), 1), ctx);
425 } else {
426 emit(rv_add(lo(rd), lo(rd), lo(rs)), ctx);
427 emit(rv_sltu(RV_REG_T0, lo(rd), lo(rs)), ctx);
428 emit(rv_add(hi(rd), hi(rd), hi(rs)), ctx);
429 emit(rv_add(hi(rd), hi(rd), RV_REG_T0), ctx);
430 }
431 break;
432 case BPF_SUB:
433 emit(rv_sub(RV_REG_T1, hi(rd), hi(rs)), ctx);
434 emit(rv_sltu(RV_REG_T0, lo(rd), lo(rs)), ctx);
435 emit(rv_sub(hi(rd), RV_REG_T1, RV_REG_T0), ctx);
436 emit(rv_sub(lo(rd), lo(rd), lo(rs)), ctx);
437 break;
438 case BPF_AND:
439 emit(rv_and(lo(rd), lo(rd), lo(rs)), ctx);
440 emit(rv_and(hi(rd), hi(rd), hi(rs)), ctx);
441 break;
442 case BPF_OR:
443 emit(rv_or(lo(rd), lo(rd), lo(rs)), ctx);
444 emit(rv_or(hi(rd), hi(rd), hi(rs)), ctx);
445 break;
446 case BPF_XOR:
447 emit(rv_xor(lo(rd), lo(rd), lo(rs)), ctx);
448 emit(rv_xor(hi(rd), hi(rd), hi(rs)), ctx);
449 break;
450 case BPF_MUL:
451 emit(rv_mul(RV_REG_T0, hi(rs), lo(rd)), ctx);
452 emit(rv_mul(hi(rd), hi(rd), lo(rs)), ctx);
453 emit(rv_mulhu(RV_REG_T1, lo(rd), lo(rs)), ctx);
454 emit(rv_add(hi(rd), hi(rd), RV_REG_T0), ctx);
455 emit(rv_mul(lo(rd), lo(rd), lo(rs)), ctx);
456 emit(rv_add(hi(rd), hi(rd), RV_REG_T1), ctx);
457 break;
458 case BPF_LSH:
459 emit(rv_addi(RV_REG_T0, lo(rs), -32), ctx);
460 emit(rv_blt(RV_REG_T0, RV_REG_ZERO, 8), ctx);
461 emit(rv_sll(hi(rd), lo(rd), RV_REG_T0), ctx);
462 emit(rv_addi(lo(rd), RV_REG_ZERO, 0), ctx);
463 emit(rv_jal(RV_REG_ZERO, 16), ctx);
464 emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 31), ctx);
465 emit(rv_srli(RV_REG_T0, lo(rd), 1), ctx);
466 emit(rv_sub(RV_REG_T1, RV_REG_T1, lo(rs)), ctx);
467 emit(rv_srl(RV_REG_T0, RV_REG_T0, RV_REG_T1), ctx);
468 emit(rv_sll(hi(rd), hi(rd), lo(rs)), ctx);
469 emit(rv_or(hi(rd), RV_REG_T0, hi(rd)), ctx);
470 emit(rv_sll(lo(rd), lo(rd), lo(rs)), ctx);
471 break;
472 case BPF_RSH:
473 emit(rv_addi(RV_REG_T0, lo(rs), -32), ctx);
474 emit(rv_blt(RV_REG_T0, RV_REG_ZERO, 8), ctx);
475 emit(rv_srl(lo(rd), hi(rd), RV_REG_T0), ctx);
476 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
477 emit(rv_jal(RV_REG_ZERO, 16), ctx);
478 emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 31), ctx);
479 emit(rv_slli(RV_REG_T0, hi(rd), 1), ctx);
480 emit(rv_sub(RV_REG_T1, RV_REG_T1, lo(rs)), ctx);
481 emit(rv_sll(RV_REG_T0, RV_REG_T0, RV_REG_T1), ctx);
482 emit(rv_srl(lo(rd), lo(rd), lo(rs)), ctx);
483 emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
484 emit(rv_srl(hi(rd), hi(rd), lo(rs)), ctx);
485 break;
486 case BPF_ARSH:
487 emit(rv_addi(RV_REG_T0, lo(rs), -32), ctx);
488 emit(rv_blt(RV_REG_T0, RV_REG_ZERO, 8), ctx);
489 emit(rv_sra(lo(rd), hi(rd), RV_REG_T0), ctx);
490 emit(rv_srai(hi(rd), hi(rd), 31), ctx);
491 emit(rv_jal(RV_REG_ZERO, 16), ctx);
492 emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 31), ctx);
493 emit(rv_slli(RV_REG_T0, hi(rd), 1), ctx);
494 emit(rv_sub(RV_REG_T1, RV_REG_T1, lo(rs)), ctx);
495 emit(rv_sll(RV_REG_T0, RV_REG_T0, RV_REG_T1), ctx);
496 emit(rv_srl(lo(rd), lo(rd), lo(rs)), ctx);
497 emit(rv_or(lo(rd), RV_REG_T0, lo(rd)), ctx);
498 emit(rv_sra(hi(rd), hi(rd), lo(rs)), ctx);
499 break;
500 case BPF_NEG:
501 emit(rv_sub(lo(rd), RV_REG_ZERO, lo(rd)), ctx);
502 emit(rv_sltu(RV_REG_T0, RV_REG_ZERO, lo(rd)), ctx);
503 emit(rv_sub(hi(rd), RV_REG_ZERO, hi(rd)), ctx);
504 emit(rv_sub(hi(rd), hi(rd), RV_REG_T0), ctx);
505 break;
506 }
507
508 bpf_put_reg64(dst, rd, ctx);
509 }
510
emit_alu_r32(const s8 * dst,const s8 * src,struct rv_jit_context * ctx,const u8 op)511 static void emit_alu_r32(const s8 *dst, const s8 *src,
512 struct rv_jit_context *ctx, const u8 op)
513 {
514 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
515 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
516 const s8 *rd = bpf_get_reg32(dst, tmp1, ctx);
517 const s8 *rs = bpf_get_reg32(src, tmp2, ctx);
518
519 switch (op) {
520 case BPF_MOV:
521 emit(rv_addi(lo(rd), lo(rs), 0), ctx);
522 break;
523 case BPF_ADD:
524 emit(rv_add(lo(rd), lo(rd), lo(rs)), ctx);
525 break;
526 case BPF_SUB:
527 emit(rv_sub(lo(rd), lo(rd), lo(rs)), ctx);
528 break;
529 case BPF_AND:
530 emit(rv_and(lo(rd), lo(rd), lo(rs)), ctx);
531 break;
532 case BPF_OR:
533 emit(rv_or(lo(rd), lo(rd), lo(rs)), ctx);
534 break;
535 case BPF_XOR:
536 emit(rv_xor(lo(rd), lo(rd), lo(rs)), ctx);
537 break;
538 case BPF_MUL:
539 emit(rv_mul(lo(rd), lo(rd), lo(rs)), ctx);
540 break;
541 case BPF_DIV:
542 emit(rv_divu(lo(rd), lo(rd), lo(rs)), ctx);
543 break;
544 case BPF_MOD:
545 emit(rv_remu(lo(rd), lo(rd), lo(rs)), ctx);
546 break;
547 case BPF_LSH:
548 emit(rv_sll(lo(rd), lo(rd), lo(rs)), ctx);
549 break;
550 case BPF_RSH:
551 emit(rv_srl(lo(rd), lo(rd), lo(rs)), ctx);
552 break;
553 case BPF_ARSH:
554 emit(rv_sra(lo(rd), lo(rd), lo(rs)), ctx);
555 break;
556 case BPF_NEG:
557 emit(rv_sub(lo(rd), RV_REG_ZERO, lo(rd)), ctx);
558 break;
559 }
560
561 bpf_put_reg32(dst, rd, ctx);
562 }
563
emit_branch_r64(const s8 * src1,const s8 * src2,s32 rvoff,struct rv_jit_context * ctx,const u8 op)564 static int emit_branch_r64(const s8 *src1, const s8 *src2, s32 rvoff,
565 struct rv_jit_context *ctx, const u8 op)
566 {
567 int e, s = ctx->ninsns;
568 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
569 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
570
571 const s8 *rs1 = bpf_get_reg64(src1, tmp1, ctx);
572 const s8 *rs2 = bpf_get_reg64(src2, tmp2, ctx);
573
574 /*
575 * NO_JUMP skips over the rest of the instructions and the
576 * emit_jump_and_link, meaning the BPF branch is not taken.
577 * JUMP skips directly to the emit_jump_and_link, meaning
578 * the BPF branch is taken.
579 *
580 * The fallthrough case results in the BPF branch being taken.
581 */
582 #define NO_JUMP(idx) (6 + (2 * (idx)))
583 #define JUMP(idx) (2 + (2 * (idx)))
584
585 switch (op) {
586 case BPF_JEQ:
587 emit(rv_bne(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
588 emit(rv_bne(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
589 break;
590 case BPF_JGT:
591 emit(rv_bgtu(hi(rs1), hi(rs2), JUMP(2)), ctx);
592 emit(rv_bltu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
593 emit(rv_bleu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
594 break;
595 case BPF_JLT:
596 emit(rv_bltu(hi(rs1), hi(rs2), JUMP(2)), ctx);
597 emit(rv_bgtu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
598 emit(rv_bgeu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
599 break;
600 case BPF_JGE:
601 emit(rv_bgtu(hi(rs1), hi(rs2), JUMP(2)), ctx);
602 emit(rv_bltu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
603 emit(rv_bltu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
604 break;
605 case BPF_JLE:
606 emit(rv_bltu(hi(rs1), hi(rs2), JUMP(2)), ctx);
607 emit(rv_bgtu(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
608 emit(rv_bgtu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
609 break;
610 case BPF_JNE:
611 emit(rv_bne(hi(rs1), hi(rs2), JUMP(1)), ctx);
612 emit(rv_beq(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
613 break;
614 case BPF_JSGT:
615 emit(rv_bgt(hi(rs1), hi(rs2), JUMP(2)), ctx);
616 emit(rv_blt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
617 emit(rv_bleu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
618 break;
619 case BPF_JSLT:
620 emit(rv_blt(hi(rs1), hi(rs2), JUMP(2)), ctx);
621 emit(rv_bgt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
622 emit(rv_bgeu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
623 break;
624 case BPF_JSGE:
625 emit(rv_bgt(hi(rs1), hi(rs2), JUMP(2)), ctx);
626 emit(rv_blt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
627 emit(rv_bltu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
628 break;
629 case BPF_JSLE:
630 emit(rv_blt(hi(rs1), hi(rs2), JUMP(2)), ctx);
631 emit(rv_bgt(hi(rs1), hi(rs2), NO_JUMP(1)), ctx);
632 emit(rv_bgtu(lo(rs1), lo(rs2), NO_JUMP(0)), ctx);
633 break;
634 case BPF_JSET:
635 emit(rv_and(RV_REG_T0, hi(rs1), hi(rs2)), ctx);
636 emit(rv_bne(RV_REG_T0, RV_REG_ZERO, JUMP(2)), ctx);
637 emit(rv_and(RV_REG_T0, lo(rs1), lo(rs2)), ctx);
638 emit(rv_beq(RV_REG_T0, RV_REG_ZERO, NO_JUMP(0)), ctx);
639 break;
640 }
641
642 #undef NO_JUMP
643 #undef JUMP
644
645 e = ctx->ninsns;
646 /* Adjust for extra insns. */
647 rvoff -= ninsns_rvoff(e - s);
648 emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx);
649 return 0;
650 }
651
emit_bcc(u8 op,u8 rd,u8 rs,int rvoff,struct rv_jit_context * ctx)652 static int emit_bcc(u8 op, u8 rd, u8 rs, int rvoff, struct rv_jit_context *ctx)
653 {
654 int e, s = ctx->ninsns;
655 bool far = false;
656 int off;
657
658 if (op == BPF_JSET) {
659 /*
660 * BPF_JSET is a special case: it has no inverse so we always
661 * treat it as a far branch.
662 */
663 far = true;
664 } else if (!is_13b_int(rvoff)) {
665 op = invert_bpf_cond(op);
666 far = true;
667 }
668
669 /*
670 * For a far branch, the condition is negated and we jump over the
671 * branch itself, and the two instructions from emit_jump_and_link.
672 * For a near branch, just use rvoff.
673 */
674 off = far ? 6 : (rvoff >> 1);
675
676 switch (op) {
677 case BPF_JEQ:
678 emit(rv_beq(rd, rs, off), ctx);
679 break;
680 case BPF_JGT:
681 emit(rv_bgtu(rd, rs, off), ctx);
682 break;
683 case BPF_JLT:
684 emit(rv_bltu(rd, rs, off), ctx);
685 break;
686 case BPF_JGE:
687 emit(rv_bgeu(rd, rs, off), ctx);
688 break;
689 case BPF_JLE:
690 emit(rv_bleu(rd, rs, off), ctx);
691 break;
692 case BPF_JNE:
693 emit(rv_bne(rd, rs, off), ctx);
694 break;
695 case BPF_JSGT:
696 emit(rv_bgt(rd, rs, off), ctx);
697 break;
698 case BPF_JSLT:
699 emit(rv_blt(rd, rs, off), ctx);
700 break;
701 case BPF_JSGE:
702 emit(rv_bge(rd, rs, off), ctx);
703 break;
704 case BPF_JSLE:
705 emit(rv_ble(rd, rs, off), ctx);
706 break;
707 case BPF_JSET:
708 emit(rv_and(RV_REG_T0, rd, rs), ctx);
709 emit(rv_beq(RV_REG_T0, RV_REG_ZERO, off), ctx);
710 break;
711 }
712
713 if (far) {
714 e = ctx->ninsns;
715 /* Adjust for extra insns. */
716 rvoff -= ninsns_rvoff(e - s);
717 emit_jump_and_link(RV_REG_ZERO, rvoff, true, ctx);
718 }
719 return 0;
720 }
721
emit_branch_r32(const s8 * src1,const s8 * src2,s32 rvoff,struct rv_jit_context * ctx,const u8 op)722 static int emit_branch_r32(const s8 *src1, const s8 *src2, s32 rvoff,
723 struct rv_jit_context *ctx, const u8 op)
724 {
725 int e, s = ctx->ninsns;
726 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
727 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
728
729 const s8 *rs1 = bpf_get_reg32(src1, tmp1, ctx);
730 const s8 *rs2 = bpf_get_reg32(src2, tmp2, ctx);
731
732 e = ctx->ninsns;
733 /* Adjust for extra insns. */
734 rvoff -= ninsns_rvoff(e - s);
735
736 if (emit_bcc(op, lo(rs1), lo(rs2), rvoff, ctx))
737 return -1;
738
739 return 0;
740 }
741
emit_call(bool fixed,u64 addr,struct rv_jit_context * ctx)742 static void emit_call(bool fixed, u64 addr, struct rv_jit_context *ctx)
743 {
744 const s8 *r0 = bpf2rv32[BPF_REG_0];
745 const s8 *r5 = bpf2rv32[BPF_REG_5];
746 u32 upper = ((u32)addr + (1 << 11)) >> 12;
747 u32 lower = addr & 0xfff;
748
749 /* R1-R4 already in correct registers---need to push R5 to stack. */
750 emit(rv_addi(RV_REG_SP, RV_REG_SP, -16), ctx);
751 emit(rv_sw(RV_REG_SP, 0, lo(r5)), ctx);
752 emit(rv_sw(RV_REG_SP, 4, hi(r5)), ctx);
753
754 /* Backup TCC. */
755 emit(rv_addi(RV_REG_TCC_SAVED, RV_REG_TCC, 0), ctx);
756
757 /*
758 * Use lui/jalr pair to jump to absolute address. Don't use emit_imm as
759 * the number of emitted instructions should not depend on the value of
760 * addr.
761 */
762 emit(rv_lui(RV_REG_T1, upper), ctx);
763 emit(rv_jalr(RV_REG_RA, RV_REG_T1, lower), ctx);
764
765 /* Restore TCC. */
766 emit(rv_addi(RV_REG_TCC, RV_REG_TCC_SAVED, 0), ctx);
767
768 /* Set return value and restore stack. */
769 emit(rv_addi(lo(r0), RV_REG_A0, 0), ctx);
770 emit(rv_addi(hi(r0), RV_REG_A1, 0), ctx);
771 emit(rv_addi(RV_REG_SP, RV_REG_SP, 16), ctx);
772 }
773
emit_bpf_tail_call(int insn,struct rv_jit_context * ctx)774 static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx)
775 {
776 /*
777 * R1 -> &ctx
778 * R2 -> &array
779 * R3 -> index
780 */
781 int tc_ninsn, off, start_insn = ctx->ninsns;
782 const s8 *arr_reg = bpf2rv32[BPF_REG_2];
783 const s8 *idx_reg = bpf2rv32[BPF_REG_3];
784
785 tc_ninsn = insn ? ctx->offset[insn] - ctx->offset[insn - 1] :
786 ctx->offset[0];
787
788 /* max_entries = array->map.max_entries; */
789 off = offsetof(struct bpf_array, map.max_entries);
790 if (is_12b_check(off, insn))
791 return -1;
792 emit(rv_lw(RV_REG_T1, off, lo(arr_reg)), ctx);
793
794 /*
795 * if (index >= max_entries)
796 * goto out;
797 */
798 off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
799 emit_bcc(BPF_JGE, lo(idx_reg), RV_REG_T1, off, ctx);
800
801 /*
802 * if (--tcc < 0)
803 * goto out;
804 */
805 emit(rv_addi(RV_REG_TCC, RV_REG_TCC, -1), ctx);
806 off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
807 emit_bcc(BPF_JSLT, RV_REG_TCC, RV_REG_ZERO, off, ctx);
808
809 /*
810 * prog = array->ptrs[index];
811 * if (!prog)
812 * goto out;
813 */
814 emit(rv_slli(RV_REG_T0, lo(idx_reg), 2), ctx);
815 emit(rv_add(RV_REG_T0, RV_REG_T0, lo(arr_reg)), ctx);
816 off = offsetof(struct bpf_array, ptrs);
817 if (is_12b_check(off, insn))
818 return -1;
819 emit(rv_lw(RV_REG_T0, off, RV_REG_T0), ctx);
820 off = ninsns_rvoff(tc_ninsn - (ctx->ninsns - start_insn));
821 emit_bcc(BPF_JEQ, RV_REG_T0, RV_REG_ZERO, off, ctx);
822
823 /*
824 * tcc = temp_tcc;
825 * goto *(prog->bpf_func + 4);
826 */
827 off = offsetof(struct bpf_prog, bpf_func);
828 if (is_12b_check(off, insn))
829 return -1;
830 emit(rv_lw(RV_REG_T0, off, RV_REG_T0), ctx);
831 /* Epilogue jumps to *(t0 + 4). */
832 __build_epilogue(true, ctx);
833 return 0;
834 }
835
emit_load_r64(const s8 * dst,const s8 * src,s16 off,struct rv_jit_context * ctx,const u8 size)836 static int emit_load_r64(const s8 *dst, const s8 *src, s16 off,
837 struct rv_jit_context *ctx, const u8 size)
838 {
839 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
840 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
841 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
842 const s8 *rs = bpf_get_reg64(src, tmp2, ctx);
843
844 emit_imm(RV_REG_T0, off, ctx);
845 emit(rv_add(RV_REG_T0, RV_REG_T0, lo(rs)), ctx);
846
847 switch (size) {
848 case BPF_B:
849 emit(rv_lbu(lo(rd), 0, RV_REG_T0), ctx);
850 if (!ctx->prog->aux->verifier_zext)
851 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
852 break;
853 case BPF_H:
854 emit(rv_lhu(lo(rd), 0, RV_REG_T0), ctx);
855 if (!ctx->prog->aux->verifier_zext)
856 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
857 break;
858 case BPF_W:
859 emit(rv_lw(lo(rd), 0, RV_REG_T0), ctx);
860 if (!ctx->prog->aux->verifier_zext)
861 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
862 break;
863 case BPF_DW:
864 emit(rv_lw(lo(rd), 0, RV_REG_T0), ctx);
865 emit(rv_lw(hi(rd), 4, RV_REG_T0), ctx);
866 break;
867 }
868
869 bpf_put_reg64(dst, rd, ctx);
870 return 0;
871 }
872
emit_store_r64(const s8 * dst,const s8 * src,s16 off,struct rv_jit_context * ctx,const u8 size,const u8 mode)873 static int emit_store_r64(const s8 *dst, const s8 *src, s16 off,
874 struct rv_jit_context *ctx, const u8 size,
875 const u8 mode)
876 {
877 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
878 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
879 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
880 const s8 *rs = bpf_get_reg64(src, tmp2, ctx);
881
882 if (mode == BPF_ATOMIC && size != BPF_W)
883 return -1;
884
885 emit_imm(RV_REG_T0, off, ctx);
886 emit(rv_add(RV_REG_T0, RV_REG_T0, lo(rd)), ctx);
887
888 switch (size) {
889 case BPF_B:
890 emit(rv_sb(RV_REG_T0, 0, lo(rs)), ctx);
891 break;
892 case BPF_H:
893 emit(rv_sh(RV_REG_T0, 0, lo(rs)), ctx);
894 break;
895 case BPF_W:
896 switch (mode) {
897 case BPF_MEM:
898 emit(rv_sw(RV_REG_T0, 0, lo(rs)), ctx);
899 break;
900 case BPF_ATOMIC: /* Only BPF_ADD supported */
901 emit(rv_amoadd_w(RV_REG_ZERO, lo(rs), RV_REG_T0, 0, 0),
902 ctx);
903 break;
904 }
905 break;
906 case BPF_DW:
907 emit(rv_sw(RV_REG_T0, 0, lo(rs)), ctx);
908 emit(rv_sw(RV_REG_T0, 4, hi(rs)), ctx);
909 break;
910 }
911
912 return 0;
913 }
914
emit_rev16(const s8 rd,struct rv_jit_context * ctx)915 static void emit_rev16(const s8 rd, struct rv_jit_context *ctx)
916 {
917 emit(rv_slli(rd, rd, 16), ctx);
918 emit(rv_slli(RV_REG_T1, rd, 8), ctx);
919 emit(rv_srli(rd, rd, 8), ctx);
920 emit(rv_add(RV_REG_T1, rd, RV_REG_T1), ctx);
921 emit(rv_srli(rd, RV_REG_T1, 16), ctx);
922 }
923
emit_rev32(const s8 rd,struct rv_jit_context * ctx)924 static void emit_rev32(const s8 rd, struct rv_jit_context *ctx)
925 {
926 emit(rv_addi(RV_REG_T1, RV_REG_ZERO, 0), ctx);
927 emit(rv_andi(RV_REG_T0, rd, 255), ctx);
928 emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
929 emit(rv_slli(RV_REG_T1, RV_REG_T1, 8), ctx);
930 emit(rv_srli(rd, rd, 8), ctx);
931 emit(rv_andi(RV_REG_T0, rd, 255), ctx);
932 emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
933 emit(rv_slli(RV_REG_T1, RV_REG_T1, 8), ctx);
934 emit(rv_srli(rd, rd, 8), ctx);
935 emit(rv_andi(RV_REG_T0, rd, 255), ctx);
936 emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
937 emit(rv_slli(RV_REG_T1, RV_REG_T1, 8), ctx);
938 emit(rv_srli(rd, rd, 8), ctx);
939 emit(rv_andi(RV_REG_T0, rd, 255), ctx);
940 emit(rv_add(RV_REG_T1, RV_REG_T1, RV_REG_T0), ctx);
941 emit(rv_addi(rd, RV_REG_T1, 0), ctx);
942 }
943
emit_zext64(const s8 * dst,struct rv_jit_context * ctx)944 static void emit_zext64(const s8 *dst, struct rv_jit_context *ctx)
945 {
946 const s8 *rd;
947 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
948
949 rd = bpf_get_reg64(dst, tmp1, ctx);
950 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
951 bpf_put_reg64(dst, rd, ctx);
952 }
953
bpf_jit_emit_insn(const struct bpf_insn * insn,struct rv_jit_context * ctx,bool extra_pass)954 int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx,
955 bool extra_pass)
956 {
957 bool is64 = BPF_CLASS(insn->code) == BPF_ALU64 ||
958 BPF_CLASS(insn->code) == BPF_JMP;
959 int s, e, rvoff, i = insn - ctx->prog->insnsi;
960 u8 code = insn->code;
961 s16 off = insn->off;
962 s32 imm = insn->imm;
963
964 const s8 *dst = bpf2rv32[insn->dst_reg];
965 const s8 *src = bpf2rv32[insn->src_reg];
966 const s8 *tmp1 = bpf2rv32[TMP_REG_1];
967 const s8 *tmp2 = bpf2rv32[TMP_REG_2];
968
969 switch (code) {
970 case BPF_ALU64 | BPF_MOV | BPF_X:
971
972 case BPF_ALU64 | BPF_ADD | BPF_X:
973 case BPF_ALU64 | BPF_ADD | BPF_K:
974
975 case BPF_ALU64 | BPF_SUB | BPF_X:
976 case BPF_ALU64 | BPF_SUB | BPF_K:
977
978 case BPF_ALU64 | BPF_AND | BPF_X:
979 case BPF_ALU64 | BPF_OR | BPF_X:
980 case BPF_ALU64 | BPF_XOR | BPF_X:
981
982 case BPF_ALU64 | BPF_MUL | BPF_X:
983 case BPF_ALU64 | BPF_MUL | BPF_K:
984
985 case BPF_ALU64 | BPF_LSH | BPF_X:
986 case BPF_ALU64 | BPF_RSH | BPF_X:
987 case BPF_ALU64 | BPF_ARSH | BPF_X:
988 if (BPF_SRC(code) == BPF_K) {
989 emit_imm32(tmp2, imm, ctx);
990 src = tmp2;
991 }
992 emit_alu_r64(dst, src, ctx, BPF_OP(code));
993 break;
994
995 case BPF_ALU64 | BPF_NEG:
996 emit_alu_r64(dst, tmp2, ctx, BPF_OP(code));
997 break;
998
999 case BPF_ALU64 | BPF_DIV | BPF_X:
1000 case BPF_ALU64 | BPF_DIV | BPF_K:
1001 case BPF_ALU64 | BPF_MOD | BPF_X:
1002 case BPF_ALU64 | BPF_MOD | BPF_K:
1003 goto notsupported;
1004
1005 case BPF_ALU64 | BPF_MOV | BPF_K:
1006 case BPF_ALU64 | BPF_AND | BPF_K:
1007 case BPF_ALU64 | BPF_OR | BPF_K:
1008 case BPF_ALU64 | BPF_XOR | BPF_K:
1009 case BPF_ALU64 | BPF_LSH | BPF_K:
1010 case BPF_ALU64 | BPF_RSH | BPF_K:
1011 case BPF_ALU64 | BPF_ARSH | BPF_K:
1012 emit_alu_i64(dst, imm, ctx, BPF_OP(code));
1013 break;
1014
1015 case BPF_ALU | BPF_MOV | BPF_X:
1016 if (imm == 1) {
1017 /* Special mov32 for zext. */
1018 emit_zext64(dst, ctx);
1019 break;
1020 }
1021 fallthrough;
1022
1023 case BPF_ALU | BPF_ADD | BPF_X:
1024 case BPF_ALU | BPF_SUB | BPF_X:
1025 case BPF_ALU | BPF_AND | BPF_X:
1026 case BPF_ALU | BPF_OR | BPF_X:
1027 case BPF_ALU | BPF_XOR | BPF_X:
1028
1029 case BPF_ALU | BPF_MUL | BPF_X:
1030 case BPF_ALU | BPF_MUL | BPF_K:
1031
1032 case BPF_ALU | BPF_DIV | BPF_X:
1033 case BPF_ALU | BPF_DIV | BPF_K:
1034
1035 case BPF_ALU | BPF_MOD | BPF_X:
1036 case BPF_ALU | BPF_MOD | BPF_K:
1037
1038 case BPF_ALU | BPF_LSH | BPF_X:
1039 case BPF_ALU | BPF_RSH | BPF_X:
1040 case BPF_ALU | BPF_ARSH | BPF_X:
1041 if (BPF_SRC(code) == BPF_K) {
1042 emit_imm32(tmp2, imm, ctx);
1043 src = tmp2;
1044 }
1045 emit_alu_r32(dst, src, ctx, BPF_OP(code));
1046 break;
1047
1048 case BPF_ALU | BPF_MOV | BPF_K:
1049 case BPF_ALU | BPF_ADD | BPF_K:
1050 case BPF_ALU | BPF_SUB | BPF_K:
1051 case BPF_ALU | BPF_AND | BPF_K:
1052 case BPF_ALU | BPF_OR | BPF_K:
1053 case BPF_ALU | BPF_XOR | BPF_K:
1054 case BPF_ALU | BPF_LSH | BPF_K:
1055 case BPF_ALU | BPF_RSH | BPF_K:
1056 case BPF_ALU | BPF_ARSH | BPF_K:
1057 /*
1058 * mul,div,mod are handled in the BPF_X case since there are
1059 * no RISC-V I-type equivalents.
1060 */
1061 emit_alu_i32(dst, imm, ctx, BPF_OP(code));
1062 break;
1063
1064 case BPF_ALU | BPF_NEG:
1065 /*
1066 * src is ignored---choose tmp2 as a dummy register since it
1067 * is not on the stack.
1068 */
1069 emit_alu_r32(dst, tmp2, ctx, BPF_OP(code));
1070 break;
1071
1072 case BPF_ALU | BPF_END | BPF_FROM_LE:
1073 {
1074 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
1075
1076 switch (imm) {
1077 case 16:
1078 emit(rv_slli(lo(rd), lo(rd), 16), ctx);
1079 emit(rv_srli(lo(rd), lo(rd), 16), ctx);
1080 fallthrough;
1081 case 32:
1082 if (!ctx->prog->aux->verifier_zext)
1083 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
1084 break;
1085 case 64:
1086 /* Do nothing. */
1087 break;
1088 default:
1089 pr_err("bpf-jit: BPF_END imm %d invalid\n", imm);
1090 return -1;
1091 }
1092
1093 bpf_put_reg64(dst, rd, ctx);
1094 break;
1095 }
1096
1097 case BPF_ALU | BPF_END | BPF_FROM_BE:
1098 {
1099 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
1100
1101 switch (imm) {
1102 case 16:
1103 emit_rev16(lo(rd), ctx);
1104 if (!ctx->prog->aux->verifier_zext)
1105 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
1106 break;
1107 case 32:
1108 emit_rev32(lo(rd), ctx);
1109 if (!ctx->prog->aux->verifier_zext)
1110 emit(rv_addi(hi(rd), RV_REG_ZERO, 0), ctx);
1111 break;
1112 case 64:
1113 /* Swap upper and lower halves. */
1114 emit(rv_addi(RV_REG_T0, lo(rd), 0), ctx);
1115 emit(rv_addi(lo(rd), hi(rd), 0), ctx);
1116 emit(rv_addi(hi(rd), RV_REG_T0, 0), ctx);
1117
1118 /* Swap each half. */
1119 emit_rev32(lo(rd), ctx);
1120 emit_rev32(hi(rd), ctx);
1121 break;
1122 default:
1123 pr_err("bpf-jit: BPF_END imm %d invalid\n", imm);
1124 return -1;
1125 }
1126
1127 bpf_put_reg64(dst, rd, ctx);
1128 break;
1129 }
1130
1131 case BPF_JMP | BPF_JA:
1132 rvoff = rv_offset(i, off, ctx);
1133 emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx);
1134 break;
1135
1136 case BPF_JMP | BPF_CALL:
1137 {
1138 bool fixed;
1139 int ret;
1140 u64 addr;
1141
1142 ret = bpf_jit_get_func_addr(ctx->prog, insn, extra_pass, &addr,
1143 &fixed);
1144 if (ret < 0)
1145 return ret;
1146 emit_call(fixed, addr, ctx);
1147 break;
1148 }
1149
1150 case BPF_JMP | BPF_TAIL_CALL:
1151 if (emit_bpf_tail_call(i, ctx))
1152 return -1;
1153 break;
1154
1155 case BPF_JMP | BPF_JEQ | BPF_X:
1156 case BPF_JMP | BPF_JEQ | BPF_K:
1157 case BPF_JMP32 | BPF_JEQ | BPF_X:
1158 case BPF_JMP32 | BPF_JEQ | BPF_K:
1159
1160 case BPF_JMP | BPF_JNE | BPF_X:
1161 case BPF_JMP | BPF_JNE | BPF_K:
1162 case BPF_JMP32 | BPF_JNE | BPF_X:
1163 case BPF_JMP32 | BPF_JNE | BPF_K:
1164
1165 case BPF_JMP | BPF_JLE | BPF_X:
1166 case BPF_JMP | BPF_JLE | BPF_K:
1167 case BPF_JMP32 | BPF_JLE | BPF_X:
1168 case BPF_JMP32 | BPF_JLE | BPF_K:
1169
1170 case BPF_JMP | BPF_JLT | BPF_X:
1171 case BPF_JMP | BPF_JLT | BPF_K:
1172 case BPF_JMP32 | BPF_JLT | BPF_X:
1173 case BPF_JMP32 | BPF_JLT | BPF_K:
1174
1175 case BPF_JMP | BPF_JGE | BPF_X:
1176 case BPF_JMP | BPF_JGE | BPF_K:
1177 case BPF_JMP32 | BPF_JGE | BPF_X:
1178 case BPF_JMP32 | BPF_JGE | BPF_K:
1179
1180 case BPF_JMP | BPF_JGT | BPF_X:
1181 case BPF_JMP | BPF_JGT | BPF_K:
1182 case BPF_JMP32 | BPF_JGT | BPF_X:
1183 case BPF_JMP32 | BPF_JGT | BPF_K:
1184
1185 case BPF_JMP | BPF_JSLE | BPF_X:
1186 case BPF_JMP | BPF_JSLE | BPF_K:
1187 case BPF_JMP32 | BPF_JSLE | BPF_X:
1188 case BPF_JMP32 | BPF_JSLE | BPF_K:
1189
1190 case BPF_JMP | BPF_JSLT | BPF_X:
1191 case BPF_JMP | BPF_JSLT | BPF_K:
1192 case BPF_JMP32 | BPF_JSLT | BPF_X:
1193 case BPF_JMP32 | BPF_JSLT | BPF_K:
1194
1195 case BPF_JMP | BPF_JSGE | BPF_X:
1196 case BPF_JMP | BPF_JSGE | BPF_K:
1197 case BPF_JMP32 | BPF_JSGE | BPF_X:
1198 case BPF_JMP32 | BPF_JSGE | BPF_K:
1199
1200 case BPF_JMP | BPF_JSGT | BPF_X:
1201 case BPF_JMP | BPF_JSGT | BPF_K:
1202 case BPF_JMP32 | BPF_JSGT | BPF_X:
1203 case BPF_JMP32 | BPF_JSGT | BPF_K:
1204
1205 case BPF_JMP | BPF_JSET | BPF_X:
1206 case BPF_JMP | BPF_JSET | BPF_K:
1207 case BPF_JMP32 | BPF_JSET | BPF_X:
1208 case BPF_JMP32 | BPF_JSET | BPF_K:
1209 rvoff = rv_offset(i, off, ctx);
1210 if (BPF_SRC(code) == BPF_K) {
1211 s = ctx->ninsns;
1212 emit_imm32(tmp2, imm, ctx);
1213 src = tmp2;
1214 e = ctx->ninsns;
1215 rvoff -= ninsns_rvoff(e - s);
1216 }
1217
1218 if (is64)
1219 emit_branch_r64(dst, src, rvoff, ctx, BPF_OP(code));
1220 else
1221 emit_branch_r32(dst, src, rvoff, ctx, BPF_OP(code));
1222 break;
1223
1224 case BPF_JMP | BPF_EXIT:
1225 if (i == ctx->prog->len - 1)
1226 break;
1227
1228 rvoff = epilogue_offset(ctx);
1229 emit_jump_and_link(RV_REG_ZERO, rvoff, false, ctx);
1230 break;
1231
1232 case BPF_LD | BPF_IMM | BPF_DW:
1233 {
1234 struct bpf_insn insn1 = insn[1];
1235 s32 imm_lo = imm;
1236 s32 imm_hi = insn1.imm;
1237 const s8 *rd = bpf_get_reg64(dst, tmp1, ctx);
1238
1239 emit_imm64(rd, imm_hi, imm_lo, ctx);
1240 bpf_put_reg64(dst, rd, ctx);
1241 return 1;
1242 }
1243
1244 case BPF_LDX | BPF_MEM | BPF_B:
1245 case BPF_LDX | BPF_MEM | BPF_H:
1246 case BPF_LDX | BPF_MEM | BPF_W:
1247 case BPF_LDX | BPF_MEM | BPF_DW:
1248 if (emit_load_r64(dst, src, off, ctx, BPF_SIZE(code)))
1249 return -1;
1250 break;
1251
1252 /* speculation barrier */
1253 case BPF_ST | BPF_NOSPEC:
1254 break;
1255
1256 case BPF_ST | BPF_MEM | BPF_B:
1257 case BPF_ST | BPF_MEM | BPF_H:
1258 case BPF_ST | BPF_MEM | BPF_W:
1259 case BPF_ST | BPF_MEM | BPF_DW:
1260
1261 case BPF_STX | BPF_MEM | BPF_B:
1262 case BPF_STX | BPF_MEM | BPF_H:
1263 case BPF_STX | BPF_MEM | BPF_W:
1264 case BPF_STX | BPF_MEM | BPF_DW:
1265 if (BPF_CLASS(code) == BPF_ST) {
1266 emit_imm32(tmp2, imm, ctx);
1267 src = tmp2;
1268 }
1269
1270 if (emit_store_r64(dst, src, off, ctx, BPF_SIZE(code),
1271 BPF_MODE(code)))
1272 return -1;
1273 break;
1274
1275 case BPF_STX | BPF_ATOMIC | BPF_W:
1276 if (insn->imm != BPF_ADD) {
1277 pr_info_once(
1278 "bpf-jit: not supported: atomic operation %02x ***\n",
1279 insn->imm);
1280 return -EFAULT;
1281 }
1282
1283 if (emit_store_r64(dst, src, off, ctx, BPF_SIZE(code),
1284 BPF_MODE(code)))
1285 return -1;
1286 break;
1287
1288 /* No hardware support for 8-byte atomics in RV32. */
1289 case BPF_STX | BPF_ATOMIC | BPF_DW:
1290 /* Fallthrough. */
1291
1292 notsupported:
1293 pr_info_once("bpf-jit: not supported: opcode %02x ***\n", code);
1294 return -EFAULT;
1295
1296 default:
1297 pr_err("bpf-jit: unknown opcode %02x\n", code);
1298 return -EINVAL;
1299 }
1300
1301 return 0;
1302 }
1303
bpf_jit_build_prologue(struct rv_jit_context * ctx)1304 void bpf_jit_build_prologue(struct rv_jit_context *ctx)
1305 {
1306 const s8 *fp = bpf2rv32[BPF_REG_FP];
1307 const s8 *r1 = bpf2rv32[BPF_REG_1];
1308 int stack_adjust = 0;
1309 int bpf_stack_adjust =
1310 round_up(ctx->prog->aux->stack_depth, STACK_ALIGN);
1311
1312 /* Make space for callee-saved registers. */
1313 stack_adjust += NR_SAVED_REGISTERS * sizeof(u32);
1314 /* Make space for BPF registers on stack. */
1315 stack_adjust += BPF_JIT_SCRATCH_REGS * sizeof(u32);
1316 /* Make space for BPF stack. */
1317 stack_adjust += bpf_stack_adjust;
1318 /* Round up for stack alignment. */
1319 stack_adjust = round_up(stack_adjust, STACK_ALIGN);
1320
1321 /*
1322 * The first instruction sets the tail-call-counter (TCC) register.
1323 * This instruction is skipped by tail calls.
1324 */
1325 emit(rv_addi(RV_REG_TCC, RV_REG_ZERO, MAX_TAIL_CALL_CNT), ctx);
1326
1327 emit(rv_addi(RV_REG_SP, RV_REG_SP, -stack_adjust), ctx);
1328
1329 /* Save callee-save registers. */
1330 emit(rv_sw(RV_REG_SP, stack_adjust - 4, RV_REG_RA), ctx);
1331 emit(rv_sw(RV_REG_SP, stack_adjust - 8, RV_REG_FP), ctx);
1332 emit(rv_sw(RV_REG_SP, stack_adjust - 12, RV_REG_S1), ctx);
1333 emit(rv_sw(RV_REG_SP, stack_adjust - 16, RV_REG_S2), ctx);
1334 emit(rv_sw(RV_REG_SP, stack_adjust - 20, RV_REG_S3), ctx);
1335 emit(rv_sw(RV_REG_SP, stack_adjust - 24, RV_REG_S4), ctx);
1336 emit(rv_sw(RV_REG_SP, stack_adjust - 28, RV_REG_S5), ctx);
1337 emit(rv_sw(RV_REG_SP, stack_adjust - 32, RV_REG_S6), ctx);
1338 emit(rv_sw(RV_REG_SP, stack_adjust - 36, RV_REG_S7), ctx);
1339
1340 /* Set fp: used as the base address for stacked BPF registers. */
1341 emit(rv_addi(RV_REG_FP, RV_REG_SP, stack_adjust), ctx);
1342
1343 /* Set up BPF frame pointer. */
1344 emit(rv_addi(lo(fp), RV_REG_SP, bpf_stack_adjust), ctx);
1345 emit(rv_addi(hi(fp), RV_REG_ZERO, 0), ctx);
1346
1347 /* Set up BPF context pointer. */
1348 emit(rv_addi(lo(r1), RV_REG_A0, 0), ctx);
1349 emit(rv_addi(hi(r1), RV_REG_ZERO, 0), ctx);
1350
1351 ctx->stack_size = stack_adjust;
1352 }
1353
bpf_jit_build_epilogue(struct rv_jit_context * ctx)1354 void bpf_jit_build_epilogue(struct rv_jit_context *ctx)
1355 {
1356 __build_epilogue(false, ctx);
1357 }
1358