Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 1 | /* |
Ingo Molnar | 063f891 | 2009-02-03 18:02:36 +0100 | [diff] [blame] | 2 | |
| 3 | x86 function call convention, 64-bit: |
| 4 | ------------------------------------- |
| 5 | arguments | callee-saved | extra caller-saved | return |
| 6 | [callee-clobbered] | | [callee-clobbered] | |
| 7 | --------------------------------------------------------------------------- |
| 8 | rdi rsi rdx rcx r8-9 | rbx rbp [*] r12-15 | r10-11 | rax, rdx [**] |
| 9 | |
| 10 | ( rsp is obviously invariant across normal function calls. (gcc can 'merge' |
| 11 | functions when it sees tail-call optimization possibilities) rflags is |
| 12 | clobbered. Leftover arguments are passed over the stack frame.) |
| 13 | |
| 14 | [*] In the frame-pointers case rbp is fixed to the stack frame. |
| 15 | |
| 16 | [**] for struct return values wider than 64 bits the return convention is a |
| 17 | bit more complex: up to 128 bits width we return small structures |
| 18 | straight in rax, rdx. For structures larger than that (3 words or |
| 19 | larger) the caller puts a pointer to an on-stack return struct |
| 20 | [allocated in the caller's stack frame] into the first argument - i.e. |
| 21 | into rdi. All other arguments shift up by one in this case. |
| 22 | Fortunately this case is rare in the kernel. |
| 23 | |
| 24 | For 32-bit we have the following conventions - kernel is built with |
| 25 | -mregparm=3 and -freg-struct-return: |
| 26 | |
| 27 | x86 function calling convention, 32-bit: |
| 28 | ---------------------------------------- |
| 29 | arguments | callee-saved | extra caller-saved | return |
| 30 | [callee-clobbered] | | [callee-clobbered] | |
| 31 | ------------------------------------------------------------------------- |
| 32 | eax edx ecx | ebx edi esi ebp [*] | <none> | eax, edx [**] |
| 33 | |
| 34 | ( here too esp is obviously invariant across normal function calls. eflags |
| 35 | is clobbered. Leftover arguments are passed over the stack frame. ) |
| 36 | |
| 37 | [*] In the frame-pointers case ebp is fixed to the stack frame. |
| 38 | |
| 39 | [**] We build with -freg-struct-return, which on 32-bit means similar |
| 40 | semantics as on 64-bit: edx can be used for a second return value |
| 41 | (i.e. covering integer and structure sizes up to 64 bits) - after that |
| 42 | it gets more complex and more expensive: 3-word or larger struct returns |
| 43 | get done in the caller's frame and the pointer to the return struct goes |
| 44 | into regparm0, i.e. eax - the other arguments shift up and the |
| 45 | function's register parameters degenerate to regparm=2 in essence. |
| 46 | |
| 47 | */ |
| 48 | |
| 49 | |
| 50 | /* |
| 51 | * 64-bit system call stack frame layout defines and helpers, |
| 52 | * for assembly code: |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 53 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 55 | #define R15 0 |
| 56 | #define R14 8 |
| 57 | #define R13 16 |
| 58 | #define R12 24 |
| 59 | #define RBP 32 |
| 60 | #define RBX 40 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
Ingo Molnar | 063f891 | 2009-02-03 18:02:36 +0100 | [diff] [blame] | 62 | /* arguments: interrupts/non tracing syscalls only save up to here: */ |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 63 | #define R11 48 |
| 64 | #define R10 56 |
| 65 | #define R9 64 |
| 66 | #define R8 72 |
| 67 | #define RAX 80 |
| 68 | #define RCX 88 |
| 69 | #define RDX 96 |
| 70 | #define RSI 104 |
| 71 | #define RDI 112 |
| 72 | #define ORIG_RAX 120 /* + error_code */ |
| 73 | /* end of arguments */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | |
Ingo Molnar | 063f891 | 2009-02-03 18:02:36 +0100 | [diff] [blame] | 75 | /* cpu exception frame or undefined in case of fast syscall: */ |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 76 | #define RIP 128 |
| 77 | #define CS 136 |
| 78 | #define EFLAGS 144 |
| 79 | #define RSP 152 |
| 80 | #define SS 160 |
| 81 | |
| 82 | #define ARGOFFSET R11 |
| 83 | #define SWFRAME ORIG_RAX |
| 84 | |
| 85 | .macro SAVE_ARGS addskip=0, norcx=0, nor891011=0 |
| 86 | subq $9*8+\addskip, %rsp |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | CFI_ADJUST_CFA_OFFSET 9*8+\addskip |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 88 | movq %rdi, 8*8(%rsp) |
| 89 | CFI_REL_OFFSET rdi, 8*8 |
| 90 | movq %rsi, 7*8(%rsp) |
| 91 | CFI_REL_OFFSET rsi, 7*8 |
| 92 | movq %rdx, 6*8(%rsp) |
| 93 | CFI_REL_OFFSET rdx, 6*8 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | .if \norcx |
| 95 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 96 | movq %rcx, 5*8(%rsp) |
| 97 | CFI_REL_OFFSET rcx, 5*8 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | .endif |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 99 | movq %rax, 4*8(%rsp) |
| 100 | CFI_REL_OFFSET rax, 4*8 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | .if \nor891011 |
| 102 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 103 | movq %r8, 3*8(%rsp) |
| 104 | CFI_REL_OFFSET r8, 3*8 |
| 105 | movq %r9, 2*8(%rsp) |
| 106 | CFI_REL_OFFSET r9, 2*8 |
| 107 | movq %r10, 1*8(%rsp) |
| 108 | CFI_REL_OFFSET r10, 1*8 |
| 109 | movq %r11, (%rsp) |
| 110 | CFI_REL_OFFSET r11, 0*8 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | .endif |
| 112 | .endm |
| 113 | |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 114 | #define ARG_SKIP 9*8 |
| 115 | |
| 116 | .macro RESTORE_ARGS skiprax=0, addskip=0, skiprcx=0, skipr11=0, \ |
| 117 | skipr8910=0, skiprdx=0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | .if \skipr11 |
| 119 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 120 | movq (%rsp), %r11 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 121 | CFI_RESTORE r11 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | .endif |
| 123 | .if \skipr8910 |
| 124 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 125 | movq 1*8(%rsp), %r10 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 126 | CFI_RESTORE r10 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 127 | movq 2*8(%rsp), %r9 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 128 | CFI_RESTORE r9 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 129 | movq 3*8(%rsp), %r8 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 130 | CFI_RESTORE r8 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | .endif |
| 132 | .if \skiprax |
| 133 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 134 | movq 4*8(%rsp), %rax |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 135 | CFI_RESTORE rax |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | .endif |
| 137 | .if \skiprcx |
| 138 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 139 | movq 5*8(%rsp), %rcx |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 140 | CFI_RESTORE rcx |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | .endif |
| 142 | .if \skiprdx |
| 143 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 144 | movq 6*8(%rsp), %rdx |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 145 | CFI_RESTORE rdx |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | .endif |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 147 | movq 7*8(%rsp), %rsi |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 148 | CFI_RESTORE rsi |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 149 | movq 8*8(%rsp), %rdi |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 150 | CFI_RESTORE rdi |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 151 | .if ARG_SKIP+\addskip > 0 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 152 | addq $ARG_SKIP+\addskip, %rsp |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | CFI_ADJUST_CFA_OFFSET -(ARG_SKIP+\addskip) |
| 154 | .endif |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 155 | .endm |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | |
Roland McGrath | d4d6715 | 2008-07-09 02:38:07 -0700 | [diff] [blame] | 157 | .macro LOAD_ARGS offset, skiprax=0 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 158 | movq \offset(%rsp), %r11 |
| 159 | movq \offset+8(%rsp), %r10 |
| 160 | movq \offset+16(%rsp), %r9 |
| 161 | movq \offset+24(%rsp), %r8 |
| 162 | movq \offset+40(%rsp), %rcx |
| 163 | movq \offset+48(%rsp), %rdx |
| 164 | movq \offset+56(%rsp), %rsi |
| 165 | movq \offset+64(%rsp), %rdi |
Roland McGrath | d4d6715 | 2008-07-09 02:38:07 -0700 | [diff] [blame] | 166 | .if \skiprax |
| 167 | .else |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 168 | movq \offset+72(%rsp), %rax |
Roland McGrath | d4d6715 | 2008-07-09 02:38:07 -0700 | [diff] [blame] | 169 | .endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | .endm |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 171 | |
| 172 | #define REST_SKIP 6*8 |
| 173 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 174 | .macro SAVE_REST |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 175 | subq $REST_SKIP, %rsp |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | CFI_ADJUST_CFA_OFFSET REST_SKIP |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 177 | movq %rbx, 5*8(%rsp) |
| 178 | CFI_REL_OFFSET rbx, 5*8 |
| 179 | movq %rbp, 4*8(%rsp) |
| 180 | CFI_REL_OFFSET rbp, 4*8 |
| 181 | movq %r12, 3*8(%rsp) |
| 182 | CFI_REL_OFFSET r12, 3*8 |
| 183 | movq %r13, 2*8(%rsp) |
| 184 | CFI_REL_OFFSET r13, 2*8 |
| 185 | movq %r14, 1*8(%rsp) |
| 186 | CFI_REL_OFFSET r14, 1*8 |
| 187 | movq %r15, (%rsp) |
| 188 | CFI_REL_OFFSET r15, 0*8 |
| 189 | .endm |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | |
| 191 | .macro RESTORE_REST |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 192 | movq (%rsp), %r15 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 193 | CFI_RESTORE r15 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 194 | movq 1*8(%rsp), %r14 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 195 | CFI_RESTORE r14 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 196 | movq 2*8(%rsp), %r13 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 197 | CFI_RESTORE r13 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 198 | movq 3*8(%rsp), %r12 |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 199 | CFI_RESTORE r12 |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 200 | movq 4*8(%rsp), %rbp |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 201 | CFI_RESTORE rbp |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 202 | movq 5*8(%rsp), %rbx |
Jan Beulich | 7effaa8 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 203 | CFI_RESTORE rbx |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 204 | addq $REST_SKIP, %rsp |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | CFI_ADJUST_CFA_OFFSET -(REST_SKIP) |
| 206 | .endm |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 207 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | .macro SAVE_ALL |
| 209 | SAVE_ARGS |
| 210 | SAVE_REST |
| 211 | .endm |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 212 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | .macro RESTORE_ALL addskip=0 |
| 214 | RESTORE_REST |
Ingo Molnar | 0c2bd5a | 2008-01-30 13:32:49 +0100 | [diff] [blame] | 215 | RESTORE_ARGS 0, \addskip |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | .endm |
| 217 | |
| 218 | .macro icebp |
| 219 | .byte 0xf1 |
| 220 | .endm |