Commit | Line | Data |
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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 | |
76f5df43 DV |
58 | /* The layout forms the "struct pt_regs" on the stack: */ |
59 | /* | |
60 | * C ABI says these regs are callee-preserved. They aren't saved on kernel entry | |
61 | * unless syscall needs a complete, fully filled "struct pt_regs". | |
62 | */ | |
63 | #define R15 0*8 | |
64 | #define R14 1*8 | |
65 | #define R13 2*8 | |
66 | #define R12 3*8 | |
67 | #define RBP 4*8 | |
68 | #define RBX 5*8 | |
69 | /* These regs are callee-clobbered. Always saved on kernel entry. */ | |
70 | #define R11 6*8 | |
71 | #define R10 7*8 | |
72 | #define R9 8*8 | |
73 | #define R8 9*8 | |
74 | #define RAX 10*8 | |
75 | #define RCX 11*8 | |
76 | #define RDX 12*8 | |
77 | #define RSI 13*8 | |
78 | #define RDI 14*8 | |
79 | /* | |
80 | * On syscall entry, this is syscall#. On CPU exception, this is error code. | |
81 | * On hw interrupt, it's IRQ number: | |
82 | */ | |
83 | #define ORIG_RAX 15*8 | |
84 | /* Return frame for iretq */ | |
85 | #define RIP 16*8 | |
86 | #define CS 17*8 | |
87 | #define EFLAGS 18*8 | |
88 | #define RSP 19*8 | |
89 | #define SS 20*8 | |
90 | ||
911d2bb5 DV |
91 | #define SIZEOF_PTREGS 21*8 |
92 | ||
76f5df43 DV |
93 | .macro ALLOC_PT_GPREGS_ON_STACK addskip=0 |
94 | subq $15*8+\addskip, %rsp | |
95 | CFI_ADJUST_CFA_OFFSET 15*8+\addskip | |
96 | .endm | |
a268fcfa | 97 | |
76f5df43 DV |
98 | .macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8plus=1 |
99 | .if \r8plus | |
100 | movq_cfi r11, 6*8+\offset | |
101 | movq_cfi r10, 7*8+\offset | |
102 | movq_cfi r9, 8*8+\offset | |
103 | movq_cfi r8, 9*8+\offset | |
54eea995 | 104 | .endif |
76f5df43 DV |
105 | .if \rax |
106 | movq_cfi rax, 10*8+\offset | |
107 | .endif | |
108 | .if \rcx | |
109 | movq_cfi rcx, 11*8+\offset | |
1da177e4 | 110 | .endif |
76f5df43 DV |
111 | movq_cfi rdx, 12*8+\offset |
112 | movq_cfi rsi, 13*8+\offset | |
113 | movq_cfi rdi, 14*8+\offset | |
114 | .endm | |
115 | .macro SAVE_C_REGS offset=0 | |
116 | SAVE_C_REGS_HELPER \offset, 1, 1, 1 | |
117 | .endm | |
118 | .macro SAVE_C_REGS_EXCEPT_RAX_RCX offset=0 | |
119 | SAVE_C_REGS_HELPER \offset, 0, 0, 1 | |
120 | .endm | |
121 | .macro SAVE_C_REGS_EXCEPT_R891011 | |
122 | SAVE_C_REGS_HELPER 0, 1, 1, 0 | |
123 | .endm | |
124 | .macro SAVE_C_REGS_EXCEPT_RCX_R891011 | |
125 | SAVE_C_REGS_HELPER 0, 1, 0, 0 | |
126 | .endm | |
a268fcfa | 127 | |
76f5df43 DV |
128 | .macro SAVE_EXTRA_REGS offset=0 |
129 | movq_cfi r15, 0*8+\offset | |
130 | movq_cfi r14, 1*8+\offset | |
131 | movq_cfi r13, 2*8+\offset | |
132 | movq_cfi r12, 3*8+\offset | |
133 | movq_cfi rbp, 4*8+\offset | |
134 | movq_cfi rbx, 5*8+\offset | |
135 | .endm | |
136 | .macro SAVE_EXTRA_REGS_RBP offset=0 | |
137 | movq_cfi rbp, 4*8+\offset | |
1da177e4 LT |
138 | .endm |
139 | ||
76f5df43 DV |
140 | .macro RESTORE_EXTRA_REGS offset=0 |
141 | movq_cfi_restore 0*8+\offset, r15 | |
142 | movq_cfi_restore 1*8+\offset, r14 | |
143 | movq_cfi_restore 2*8+\offset, r13 | |
144 | movq_cfi_restore 3*8+\offset, r12 | |
145 | movq_cfi_restore 4*8+\offset, rbp | |
146 | movq_cfi_restore 5*8+\offset, rbx | |
147 | .endm | |
0c2bd5a5 | 148 | |
76f5df43 | 149 | .macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1 |
838feb47 | 150 | .if \rstor_r11 |
76f5df43 | 151 | movq_cfi_restore 6*8, r11 |
1da177e4 | 152 | .endif |
838feb47 | 153 | .if \rstor_r8910 |
76f5df43 DV |
154 | movq_cfi_restore 7*8, r10 |
155 | movq_cfi_restore 8*8, r9 | |
156 | movq_cfi_restore 9*8, r8 | |
1da177e4 | 157 | .endif |
838feb47 | 158 | .if \rstor_rax |
76f5df43 | 159 | movq_cfi_restore 10*8, rax |
1da177e4 | 160 | .endif |
838feb47 | 161 | .if \rstor_rcx |
76f5df43 | 162 | movq_cfi_restore 11*8, rcx |
1da177e4 | 163 | .endif |
838feb47 | 164 | .if \rstor_rdx |
76f5df43 | 165 | movq_cfi_restore 12*8, rdx |
1da177e4 | 166 | .endif |
76f5df43 DV |
167 | movq_cfi_restore 13*8, rsi |
168 | movq_cfi_restore 14*8, rdi | |
0c2bd5a5 | 169 | .endm |
76f5df43 DV |
170 | .macro RESTORE_C_REGS |
171 | RESTORE_C_REGS_HELPER 1,1,1,1,1 | |
1da177e4 | 172 | .endm |
76f5df43 DV |
173 | .macro RESTORE_C_REGS_EXCEPT_RAX |
174 | RESTORE_C_REGS_HELPER 0,1,1,1,1 | |
0c2bd5a5 | 175 | .endm |
76f5df43 DV |
176 | .macro RESTORE_C_REGS_EXCEPT_RCX |
177 | RESTORE_C_REGS_HELPER 1,0,1,1,1 | |
1da177e4 | 178 | .endm |
d441c1f2 DV |
179 | .macro RESTORE_C_REGS_EXCEPT_R11 |
180 | RESTORE_C_REGS_HELPER 1,1,0,1,1 | |
181 | .endm | |
76f5df43 DV |
182 | .macro RESTORE_RSI_RDI |
183 | RESTORE_C_REGS_HELPER 0,0,0,0,0 | |
184 | .endm | |
185 | .macro RESTORE_RSI_RDI_RDX | |
186 | RESTORE_C_REGS_HELPER 0,0,0,0,1 | |
1da177e4 | 187 | .endm |
0c2bd5a5 | 188 | |
76f5df43 DV |
189 | .macro REMOVE_PT_GPREGS_FROM_STACK addskip=0 |
190 | addq $15*8+\addskip, %rsp | |
191 | CFI_ADJUST_CFA_OFFSET -(15*8+\addskip) | |
1da177e4 LT |
192 | .endm |
193 | ||
194 | .macro icebp | |
195 | .byte 0xf1 | |
196 | .endm | |
1a338ac3 PZ |
197 | |
198 | #else /* CONFIG_X86_64 */ | |
199 | ||
200 | /* | |
201 | * For 32bit only simplified versions of SAVE_ALL/RESTORE_ALL. These | |
202 | * are different from the entry_32.S versions in not changing the segment | |
203 | * registers. So only suitable for in kernel use, not when transitioning | |
204 | * from or to user space. The resulting stack frame is not a standard | |
205 | * pt_regs frame. The main use case is calling C code from assembler | |
206 | * when all the registers need to be preserved. | |
207 | */ | |
208 | ||
209 | .macro SAVE_ALL | |
49db46a6 DV |
210 | pushl_cfi_reg eax |
211 | pushl_cfi_reg ebp | |
212 | pushl_cfi_reg edi | |
213 | pushl_cfi_reg esi | |
214 | pushl_cfi_reg edx | |
215 | pushl_cfi_reg ecx | |
216 | pushl_cfi_reg ebx | |
1a338ac3 PZ |
217 | .endm |
218 | ||
219 | .macro RESTORE_ALL | |
49db46a6 DV |
220 | popl_cfi_reg ebx |
221 | popl_cfi_reg ecx | |
222 | popl_cfi_reg edx | |
223 | popl_cfi_reg esi | |
224 | popl_cfi_reg edi | |
225 | popl_cfi_reg ebp | |
226 | popl_cfi_reg eax | |
1a338ac3 PZ |
227 | .endm |
228 | ||
229 | #endif /* CONFIG_X86_64 */ | |
230 |