1478dc89cSAndy Lutomirski #include <linux/jump_label.h> 28c1f7558SJosh Poimboeuf #include <asm/unwind_hints.h> 3478dc89cSAndy Lutomirski 4d36f9479SIngo Molnar /* 5d36f9479SIngo Molnar 6d36f9479SIngo Molnar x86 function call convention, 64-bit: 7d36f9479SIngo Molnar ------------------------------------- 8d36f9479SIngo Molnar arguments | callee-saved | extra caller-saved | return 9d36f9479SIngo Molnar [callee-clobbered] | | [callee-clobbered] | 10d36f9479SIngo Molnar --------------------------------------------------------------------------- 11d36f9479SIngo Molnar rdi rsi rdx rcx r8-9 | rbx rbp [*] r12-15 | r10-11 | rax, rdx [**] 12d36f9479SIngo Molnar 13d36f9479SIngo Molnar ( rsp is obviously invariant across normal function calls. (gcc can 'merge' 14d36f9479SIngo Molnar functions when it sees tail-call optimization possibilities) rflags is 15d36f9479SIngo Molnar clobbered. Leftover arguments are passed over the stack frame.) 16d36f9479SIngo Molnar 17d36f9479SIngo Molnar [*] In the frame-pointers case rbp is fixed to the stack frame. 18d36f9479SIngo Molnar 19d36f9479SIngo Molnar [**] for struct return values wider than 64 bits the return convention is a 20d36f9479SIngo Molnar bit more complex: up to 128 bits width we return small structures 21d36f9479SIngo Molnar straight in rax, rdx. For structures larger than that (3 words or 22d36f9479SIngo Molnar larger) the caller puts a pointer to an on-stack return struct 23d36f9479SIngo Molnar [allocated in the caller's stack frame] into the first argument - i.e. 24d36f9479SIngo Molnar into rdi. All other arguments shift up by one in this case. 25d36f9479SIngo Molnar Fortunately this case is rare in the kernel. 26d36f9479SIngo Molnar 27d36f9479SIngo Molnar For 32-bit we have the following conventions - kernel is built with 28d36f9479SIngo Molnar -mregparm=3 and -freg-struct-return: 29d36f9479SIngo Molnar 30d36f9479SIngo Molnar x86 function calling convention, 32-bit: 31d36f9479SIngo Molnar ---------------------------------------- 32d36f9479SIngo Molnar arguments | callee-saved | extra caller-saved | return 33d36f9479SIngo Molnar [callee-clobbered] | | [callee-clobbered] | 34d36f9479SIngo Molnar ------------------------------------------------------------------------- 35d36f9479SIngo Molnar eax edx ecx | ebx edi esi ebp [*] | <none> | eax, edx [**] 36d36f9479SIngo Molnar 37d36f9479SIngo Molnar ( here too esp is obviously invariant across normal function calls. eflags 38d36f9479SIngo Molnar is clobbered. Leftover arguments are passed over the stack frame. ) 39d36f9479SIngo Molnar 40d36f9479SIngo Molnar [*] In the frame-pointers case ebp is fixed to the stack frame. 41d36f9479SIngo Molnar 42d36f9479SIngo Molnar [**] We build with -freg-struct-return, which on 32-bit means similar 43d36f9479SIngo Molnar semantics as on 64-bit: edx can be used for a second return value 44d36f9479SIngo Molnar (i.e. covering integer and structure sizes up to 64 bits) - after that 45d36f9479SIngo Molnar it gets more complex and more expensive: 3-word or larger struct returns 46d36f9479SIngo Molnar get done in the caller's frame and the pointer to the return struct goes 47d36f9479SIngo Molnar into regparm0, i.e. eax - the other arguments shift up and the 48d36f9479SIngo Molnar function's register parameters degenerate to regparm=2 in essence. 49d36f9479SIngo Molnar 50d36f9479SIngo Molnar */ 51d36f9479SIngo Molnar 52d36f9479SIngo Molnar #ifdef CONFIG_X86_64 53d36f9479SIngo Molnar 54d36f9479SIngo Molnar /* 55d36f9479SIngo Molnar * 64-bit system call stack frame layout defines and helpers, 56d36f9479SIngo Molnar * for assembly code: 57d36f9479SIngo Molnar */ 58d36f9479SIngo Molnar 59d36f9479SIngo Molnar /* The layout forms the "struct pt_regs" on the stack: */ 60d36f9479SIngo Molnar /* 61d36f9479SIngo Molnar * C ABI says these regs are callee-preserved. They aren't saved on kernel entry 62d36f9479SIngo Molnar * unless syscall needs a complete, fully filled "struct pt_regs". 63d36f9479SIngo Molnar */ 64d36f9479SIngo Molnar #define R15 0*8 65d36f9479SIngo Molnar #define R14 1*8 66d36f9479SIngo Molnar #define R13 2*8 67d36f9479SIngo Molnar #define R12 3*8 68d36f9479SIngo Molnar #define RBP 4*8 69d36f9479SIngo Molnar #define RBX 5*8 70d36f9479SIngo Molnar /* These regs are callee-clobbered. Always saved on kernel entry. */ 71d36f9479SIngo Molnar #define R11 6*8 72d36f9479SIngo Molnar #define R10 7*8 73d36f9479SIngo Molnar #define R9 8*8 74d36f9479SIngo Molnar #define R8 9*8 75d36f9479SIngo Molnar #define RAX 10*8 76d36f9479SIngo Molnar #define RCX 11*8 77d36f9479SIngo Molnar #define RDX 12*8 78d36f9479SIngo Molnar #define RSI 13*8 79d36f9479SIngo Molnar #define RDI 14*8 80d36f9479SIngo Molnar /* 81d36f9479SIngo Molnar * On syscall entry, this is syscall#. On CPU exception, this is error code. 82d36f9479SIngo Molnar * On hw interrupt, it's IRQ number: 83d36f9479SIngo Molnar */ 84d36f9479SIngo Molnar #define ORIG_RAX 15*8 85d36f9479SIngo Molnar /* Return frame for iretq */ 86d36f9479SIngo Molnar #define RIP 16*8 87d36f9479SIngo Molnar #define CS 17*8 88d36f9479SIngo Molnar #define EFLAGS 18*8 89d36f9479SIngo Molnar #define RSP 19*8 90d36f9479SIngo Molnar #define SS 20*8 91d36f9479SIngo Molnar 92d36f9479SIngo Molnar #define SIZEOF_PTREGS 21*8 93d36f9479SIngo Molnar 9459df2268SAlexander Kuleshov .macro ALLOC_PT_GPREGS_ON_STACK 9559df2268SAlexander Kuleshov addq $-(15*8), %rsp 96d36f9479SIngo Molnar .endm 97d36f9479SIngo Molnar 98d36f9479SIngo Molnar .macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1 99d36f9479SIngo Molnar .if \r11 100d36f9479SIngo Molnar movq %r11, 6*8+\offset(%rsp) 101d36f9479SIngo Molnar .endif 102d36f9479SIngo Molnar .if \r8910 103d36f9479SIngo Molnar movq %r10, 7*8+\offset(%rsp) 104d36f9479SIngo Molnar movq %r9, 8*8+\offset(%rsp) 105d36f9479SIngo Molnar movq %r8, 9*8+\offset(%rsp) 106d36f9479SIngo Molnar .endif 107d36f9479SIngo Molnar .if \rax 108d36f9479SIngo Molnar movq %rax, 10*8+\offset(%rsp) 109d36f9479SIngo Molnar .endif 110d36f9479SIngo Molnar .if \rcx 111d36f9479SIngo Molnar movq %rcx, 11*8+\offset(%rsp) 112d36f9479SIngo Molnar .endif 113d36f9479SIngo Molnar movq %rdx, 12*8+\offset(%rsp) 114d36f9479SIngo Molnar movq %rsi, 13*8+\offset(%rsp) 115d36f9479SIngo Molnar movq %rdi, 14*8+\offset(%rsp) 1168c1f7558SJosh Poimboeuf UNWIND_HINT_REGS offset=\offset extra=0 117d36f9479SIngo Molnar .endm 118d36f9479SIngo Molnar .macro SAVE_C_REGS offset=0 119d36f9479SIngo Molnar SAVE_C_REGS_HELPER \offset, 1, 1, 1, 1 120d36f9479SIngo Molnar .endm 121d36f9479SIngo Molnar .macro SAVE_C_REGS_EXCEPT_RAX_RCX offset=0 122d36f9479SIngo Molnar SAVE_C_REGS_HELPER \offset, 0, 0, 1, 1 123d36f9479SIngo Molnar .endm 124d36f9479SIngo Molnar .macro SAVE_C_REGS_EXCEPT_R891011 125d36f9479SIngo Molnar SAVE_C_REGS_HELPER 0, 1, 1, 0, 0 126d36f9479SIngo Molnar .endm 127d36f9479SIngo Molnar .macro SAVE_C_REGS_EXCEPT_RCX_R891011 128d36f9479SIngo Molnar SAVE_C_REGS_HELPER 0, 1, 0, 0, 0 129d36f9479SIngo Molnar .endm 130d36f9479SIngo Molnar .macro SAVE_C_REGS_EXCEPT_RAX_RCX_R11 131d36f9479SIngo Molnar SAVE_C_REGS_HELPER 0, 0, 0, 1, 0 132d36f9479SIngo Molnar .endm 133d36f9479SIngo Molnar 134d36f9479SIngo Molnar .macro SAVE_EXTRA_REGS offset=0 135d36f9479SIngo Molnar movq %r15, 0*8+\offset(%rsp) 136d36f9479SIngo Molnar movq %r14, 1*8+\offset(%rsp) 137d36f9479SIngo Molnar movq %r13, 2*8+\offset(%rsp) 138d36f9479SIngo Molnar movq %r12, 3*8+\offset(%rsp) 139d36f9479SIngo Molnar movq %rbp, 4*8+\offset(%rsp) 140d36f9479SIngo Molnar movq %rbx, 5*8+\offset(%rsp) 1418c1f7558SJosh Poimboeuf UNWIND_HINT_REGS offset=\offset 142d36f9479SIngo Molnar .endm 143d36f9479SIngo Molnar 144d36f9479SIngo Molnar .macro RESTORE_EXTRA_REGS offset=0 145d36f9479SIngo Molnar movq 0*8+\offset(%rsp), %r15 146d36f9479SIngo Molnar movq 1*8+\offset(%rsp), %r14 147d36f9479SIngo Molnar movq 2*8+\offset(%rsp), %r13 148d36f9479SIngo Molnar movq 3*8+\offset(%rsp), %r12 149d36f9479SIngo Molnar movq 4*8+\offset(%rsp), %rbp 150d36f9479SIngo Molnar movq 5*8+\offset(%rsp), %rbx 1518c1f7558SJosh Poimboeuf UNWIND_HINT_REGS offset=\offset extra=0 152d36f9479SIngo Molnar .endm 153d36f9479SIngo Molnar 154d36f9479SIngo Molnar .macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1 155d36f9479SIngo Molnar .if \rstor_r11 156d36f9479SIngo Molnar movq 6*8(%rsp), %r11 157d36f9479SIngo Molnar .endif 158d36f9479SIngo Molnar .if \rstor_r8910 159d36f9479SIngo Molnar movq 7*8(%rsp), %r10 160d36f9479SIngo Molnar movq 8*8(%rsp), %r9 161d36f9479SIngo Molnar movq 9*8(%rsp), %r8 162d36f9479SIngo Molnar .endif 163d36f9479SIngo Molnar .if \rstor_rax 164d36f9479SIngo Molnar movq 10*8(%rsp), %rax 165d36f9479SIngo Molnar .endif 166d36f9479SIngo Molnar .if \rstor_rcx 167d36f9479SIngo Molnar movq 11*8(%rsp), %rcx 168d36f9479SIngo Molnar .endif 169d36f9479SIngo Molnar .if \rstor_rdx 170d36f9479SIngo Molnar movq 12*8(%rsp), %rdx 171d36f9479SIngo Molnar .endif 172d36f9479SIngo Molnar movq 13*8(%rsp), %rsi 173d36f9479SIngo Molnar movq 14*8(%rsp), %rdi 1748c1f7558SJosh Poimboeuf UNWIND_HINT_IRET_REGS offset=16*8 175d36f9479SIngo Molnar .endm 176d36f9479SIngo Molnar .macro RESTORE_C_REGS 177d36f9479SIngo Molnar RESTORE_C_REGS_HELPER 1,1,1,1,1 178d36f9479SIngo Molnar .endm 179d36f9479SIngo Molnar .macro RESTORE_C_REGS_EXCEPT_RAX 180d36f9479SIngo Molnar RESTORE_C_REGS_HELPER 0,1,1,1,1 181d36f9479SIngo Molnar .endm 182d36f9479SIngo Molnar .macro RESTORE_C_REGS_EXCEPT_RCX 183d36f9479SIngo Molnar RESTORE_C_REGS_HELPER 1,0,1,1,1 184d36f9479SIngo Molnar .endm 185d36f9479SIngo Molnar .macro RESTORE_C_REGS_EXCEPT_R11 186d36f9479SIngo Molnar RESTORE_C_REGS_HELPER 1,1,0,1,1 187d36f9479SIngo Molnar .endm 188d36f9479SIngo Molnar .macro RESTORE_C_REGS_EXCEPT_RCX_R11 189d36f9479SIngo Molnar RESTORE_C_REGS_HELPER 1,0,0,1,1 190d36f9479SIngo Molnar .endm 191d36f9479SIngo Molnar 192d36f9479SIngo Molnar .macro REMOVE_PT_GPREGS_FROM_STACK addskip=0 193d36f9479SIngo Molnar subq $-(15*8+\addskip), %rsp 194d36f9479SIngo Molnar .endm 195d36f9479SIngo Molnar 196d36f9479SIngo Molnar .macro icebp 197d36f9479SIngo Molnar .byte 0xf1 198d36f9479SIngo Molnar .endm 199d36f9479SIngo Molnar 200946c1911SJosh Poimboeuf /* 201946c1911SJosh Poimboeuf * This is a sneaky trick to help the unwinder find pt_regs on the stack. The 202946c1911SJosh Poimboeuf * frame pointer is replaced with an encoded pointer to pt_regs. The encoding 203946c1911SJosh Poimboeuf * is just setting the LSB, which makes it an invalid stack address and is also 204946c1911SJosh Poimboeuf * a signal to the unwinder that it's a pt_regs pointer in disguise. 205946c1911SJosh Poimboeuf * 206946c1911SJosh Poimboeuf * NOTE: This macro must be used *after* SAVE_EXTRA_REGS because it corrupts 207946c1911SJosh Poimboeuf * the original rbp. 208946c1911SJosh Poimboeuf */ 209946c1911SJosh Poimboeuf .macro ENCODE_FRAME_POINTER ptregs_offset=0 210946c1911SJosh Poimboeuf #ifdef CONFIG_FRAME_POINTER 211946c1911SJosh Poimboeuf .if \ptregs_offset 212946c1911SJosh Poimboeuf leaq \ptregs_offset(%rsp), %rbp 213946c1911SJosh Poimboeuf .else 214946c1911SJosh Poimboeuf mov %rsp, %rbp 215946c1911SJosh Poimboeuf .endif 216946c1911SJosh Poimboeuf orq $0x1, %rbp 217946c1911SJosh Poimboeuf #endif 218946c1911SJosh Poimboeuf .endm 219946c1911SJosh Poimboeuf 220d36f9479SIngo Molnar #endif /* CONFIG_X86_64 */ 221d36f9479SIngo Molnar 222478dc89cSAndy Lutomirski /* 223478dc89cSAndy Lutomirski * This does 'call enter_from_user_mode' unless we can avoid it based on 224478dc89cSAndy Lutomirski * kernel config or using the static jump infrastructure. 225478dc89cSAndy Lutomirski */ 226478dc89cSAndy Lutomirski .macro CALL_enter_from_user_mode 227478dc89cSAndy Lutomirski #ifdef CONFIG_CONTEXT_TRACKING 228478dc89cSAndy Lutomirski #ifdef HAVE_JUMP_LABEL 229478dc89cSAndy Lutomirski STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0 230478dc89cSAndy Lutomirski #endif 231478dc89cSAndy Lutomirski call enter_from_user_mode 232478dc89cSAndy Lutomirski .Lafter_call_\@: 233478dc89cSAndy Lutomirski #endif 234478dc89cSAndy Lutomirski .endm 235