Commit | Line | Data |
---|---|---|
0c2bd5a5 | 1 | /* |
063f8913 IM |
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 | ||
a1ce3928 | 49 | #include <asm/dwarf2.h> |
063f8913 | 50 | |
1a338ac3 PZ |
51 | #ifdef CONFIG_X86_64 |
52 | ||
063f8913 | 53 | /* |
1b2b23d8 TG |
54 | * 64-bit system call stack frame layout defines and helpers, |
55 | * for assembly code: | |
0c2bd5a5 | 56 | */ |
1da177e4 | 57 | |
1b2b23d8 TG |
58 | #define R15 0 |
59 | #define R14 8 | |
60 | #define R13 16 | |
61 | #define R12 24 | |
62 | #define RBP 32 | |
63 | #define RBX 40 | |
1da177e4 | 64 | |
063f8913 | 65 | /* arguments: interrupts/non tracing syscalls only save up to here: */ |
1b2b23d8 TG |
66 | #define R11 48 |
67 | #define R10 56 | |
68 | #define R9 64 | |
69 | #define R8 72 | |
70 | #define RAX 80 | |
71 | #define RCX 88 | |
72 | #define RDX 96 | |
73 | #define RSI 104 | |
74 | #define RDI 112 | |
75 | #define ORIG_RAX 120 /* + error_code */ | |
0c2bd5a5 IM |
76 | /* end of arguments */ |
77 | ||
063f8913 | 78 | /* cpu exception frame or undefined in case of fast syscall: */ |
1b2b23d8 TG |
79 | #define RIP 128 |
80 | #define CS 136 | |
81 | #define EFLAGS 144 | |
82 | #define RSP 152 | |
83 | #define SS 160 | |
0c2bd5a5 IM |
84 | |
85 | #define ARGOFFSET R11 | |
1da177e4 | 86 | |
54eea995 | 87 | .macro SAVE_ARGS addskip=0, save_rcx=1, save_r891011=1, rax_enosys=0 |
0c2bd5a5 | 88 | subq $9*8+\addskip, %rsp |
1da177e4 | 89 | CFI_ADJUST_CFA_OFFSET 9*8+\addskip |
a268fcfa BP |
90 | movq_cfi rdi, 8*8 |
91 | movq_cfi rsi, 7*8 | |
92 | movq_cfi rdx, 6*8 | |
93 | ||
cac0e0a7 | 94 | .if \save_rcx |
a268fcfa | 95 | movq_cfi rcx, 5*8 |
1da177e4 | 96 | .endif |
a268fcfa | 97 | |
54eea995 AL |
98 | .if \rax_enosys |
99 | movq $-ENOSYS, 4*8(%rsp) | |
100 | .else | |
a268fcfa | 101 | movq_cfi rax, 4*8 |
54eea995 | 102 | .endif |
a268fcfa | 103 | |
cac0e0a7 | 104 | .if \save_r891011 |
a268fcfa BP |
105 | movq_cfi r8, 3*8 |
106 | movq_cfi r9, 2*8 | |
107 | movq_cfi r10, 1*8 | |
108 | movq_cfi r11, 0*8 | |
1da177e4 | 109 | .endif |
a268fcfa | 110 | |
1da177e4 LT |
111 | .endm |
112 | ||
3234282f | 113 | #define ARG_SKIP (9*8) |
0c2bd5a5 | 114 | |
838feb47 BP |
115 | .macro RESTORE_ARGS rstor_rax=1, addskip=0, rstor_rcx=1, rstor_r11=1, \ |
116 | rstor_r8910=1, rstor_rdx=1 | |
117 | .if \rstor_r11 | |
a268fcfa | 118 | movq_cfi_restore 0*8, r11 |
1da177e4 | 119 | .endif |
a268fcfa | 120 | |
838feb47 | 121 | .if \rstor_r8910 |
a268fcfa BP |
122 | movq_cfi_restore 1*8, r10 |
123 | movq_cfi_restore 2*8, r9 | |
124 | movq_cfi_restore 3*8, r8 | |
1da177e4 | 125 | .endif |
a268fcfa | 126 | |
838feb47 | 127 | .if \rstor_rax |
a268fcfa | 128 | movq_cfi_restore 4*8, rax |
1da177e4 | 129 | .endif |
a268fcfa | 130 | |
838feb47 | 131 | .if \rstor_rcx |
a268fcfa | 132 | movq_cfi_restore 5*8, rcx |
1da177e4 | 133 | .endif |
a268fcfa | 134 | |
838feb47 | 135 | .if \rstor_rdx |
a268fcfa | 136 | movq_cfi_restore 6*8, rdx |
1da177e4 | 137 | .endif |
a268fcfa BP |
138 | |
139 | movq_cfi_restore 7*8, rsi | |
140 | movq_cfi_restore 8*8, rdi | |
141 | ||
1da177e4 | 142 | .if ARG_SKIP+\addskip > 0 |
0c2bd5a5 | 143 | addq $ARG_SKIP+\addskip, %rsp |
1da177e4 LT |
144 | CFI_ADJUST_CFA_OFFSET -(ARG_SKIP+\addskip) |
145 | .endif | |
0c2bd5a5 | 146 | .endm |
1da177e4 | 147 | |
d4d67150 | 148 | .macro LOAD_ARGS offset, skiprax=0 |
0c2bd5a5 IM |
149 | movq \offset(%rsp), %r11 |
150 | movq \offset+8(%rsp), %r10 | |
151 | movq \offset+16(%rsp), %r9 | |
152 | movq \offset+24(%rsp), %r8 | |
153 | movq \offset+40(%rsp), %rcx | |
154 | movq \offset+48(%rsp), %rdx | |
155 | movq \offset+56(%rsp), %rsi | |
156 | movq \offset+64(%rsp), %rdi | |
d4d67150 RM |
157 | .if \skiprax |
158 | .else | |
0c2bd5a5 | 159 | movq \offset+72(%rsp), %rax |
d4d67150 | 160 | .endif |
1da177e4 | 161 | .endm |
0c2bd5a5 | 162 | |
3234282f | 163 | #define REST_SKIP (6*8) |
0c2bd5a5 | 164 | |
1da177e4 | 165 | .macro SAVE_REST |
0c2bd5a5 | 166 | subq $REST_SKIP, %rsp |
1da177e4 | 167 | CFI_ADJUST_CFA_OFFSET REST_SKIP |
a268fcfa BP |
168 | movq_cfi rbx, 5*8 |
169 | movq_cfi rbp, 4*8 | |
170 | movq_cfi r12, 3*8 | |
171 | movq_cfi r13, 2*8 | |
172 | movq_cfi r14, 1*8 | |
173 | movq_cfi r15, 0*8 | |
0c2bd5a5 | 174 | .endm |
1da177e4 LT |
175 | |
176 | .macro RESTORE_REST | |
a268fcfa BP |
177 | movq_cfi_restore 0*8, r15 |
178 | movq_cfi_restore 1*8, r14 | |
179 | movq_cfi_restore 2*8, r13 | |
180 | movq_cfi_restore 3*8, r12 | |
181 | movq_cfi_restore 4*8, rbp | |
182 | movq_cfi_restore 5*8, rbx | |
0c2bd5a5 | 183 | addq $REST_SKIP, %rsp |
1da177e4 LT |
184 | CFI_ADJUST_CFA_OFFSET -(REST_SKIP) |
185 | .endm | |
0c2bd5a5 | 186 | |
1da177e4 LT |
187 | .macro SAVE_ALL |
188 | SAVE_ARGS | |
189 | SAVE_REST | |
190 | .endm | |
0c2bd5a5 | 191 | |
1da177e4 LT |
192 | .macro RESTORE_ALL addskip=0 |
193 | RESTORE_REST | |
838feb47 | 194 | RESTORE_ARGS 1, \addskip |
1da177e4 LT |
195 | .endm |
196 | ||
197 | .macro icebp | |
198 | .byte 0xf1 | |
199 | .endm | |
1a338ac3 PZ |
200 | |
201 | #else /* CONFIG_X86_64 */ | |
202 | ||
203 | /* | |
204 | * For 32bit only simplified versions of SAVE_ALL/RESTORE_ALL. These | |
205 | * are different from the entry_32.S versions in not changing the segment | |
206 | * registers. So only suitable for in kernel use, not when transitioning | |
207 | * from or to user space. The resulting stack frame is not a standard | |
208 | * pt_regs frame. The main use case is calling C code from assembler | |
209 | * when all the registers need to be preserved. | |
210 | */ | |
211 | ||
212 | .macro SAVE_ALL | |
213 | pushl_cfi %eax | |
214 | CFI_REL_OFFSET eax, 0 | |
215 | pushl_cfi %ebp | |
216 | CFI_REL_OFFSET ebp, 0 | |
217 | pushl_cfi %edi | |
218 | CFI_REL_OFFSET edi, 0 | |
219 | pushl_cfi %esi | |
220 | CFI_REL_OFFSET esi, 0 | |
221 | pushl_cfi %edx | |
222 | CFI_REL_OFFSET edx, 0 | |
223 | pushl_cfi %ecx | |
224 | CFI_REL_OFFSET ecx, 0 | |
225 | pushl_cfi %ebx | |
226 | CFI_REL_OFFSET ebx, 0 | |
227 | .endm | |
228 | ||
229 | .macro RESTORE_ALL | |
230 | popl_cfi %ebx | |
231 | CFI_RESTORE ebx | |
232 | popl_cfi %ecx | |
233 | CFI_RESTORE ecx | |
234 | popl_cfi %edx | |
235 | CFI_RESTORE edx | |
236 | popl_cfi %esi | |
237 | CFI_RESTORE esi | |
238 | popl_cfi %edi | |
239 | CFI_RESTORE edi | |
240 | popl_cfi %ebp | |
241 | CFI_RESTORE ebp | |
242 | popl_cfi %eax | |
243 | CFI_RESTORE eax | |
244 | .endm | |
245 | ||
246 | #endif /* CONFIG_X86_64 */ | |
247 |