You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
222 lines
5.6 KiB
222 lines
5.6 KiB
/*
|
|
|
|
x86 function call convention, 64-bit:
|
|
-------------------------------------
|
|
arguments | callee-saved | extra caller-saved | return
|
|
[callee-clobbered] | | [callee-clobbered] |
|
|
---------------------------------------------------------------------------
|
|
rdi rsi rdx rcx r8-9 | rbx rbp [*] r12-15 | r10-11 | rax, rdx [**]
|
|
|
|
( rsp is obviously invariant across normal function calls. (gcc can 'merge'
|
|
functions when it sees tail-call optimization possibilities) rflags is
|
|
clobbered. Leftover arguments are passed over the stack frame.)
|
|
|
|
[*] In the frame-pointers case rbp is fixed to the stack frame.
|
|
|
|
[**] for struct return values wider than 64 bits the return convention is a
|
|
bit more complex: up to 128 bits width we return small structures
|
|
straight in rax, rdx. For structures larger than that (3 words or
|
|
larger) the caller puts a pointer to an on-stack return struct
|
|
[allocated in the caller's stack frame] into the first argument - i.e.
|
|
into rdi. All other arguments shift up by one in this case.
|
|
Fortunately this case is rare in the kernel.
|
|
|
|
For 32-bit we have the following conventions - kernel is built with
|
|
-mregparm=3 and -freg-struct-return:
|
|
|
|
x86 function calling convention, 32-bit:
|
|
----------------------------------------
|
|
arguments | callee-saved | extra caller-saved | return
|
|
[callee-clobbered] | | [callee-clobbered] |
|
|
-------------------------------------------------------------------------
|
|
eax edx ecx | ebx edi esi ebp [*] | <none> | eax, edx [**]
|
|
|
|
( here too esp is obviously invariant across normal function calls. eflags
|
|
is clobbered. Leftover arguments are passed over the stack frame. )
|
|
|
|
[*] In the frame-pointers case ebp is fixed to the stack frame.
|
|
|
|
[**] We build with -freg-struct-return, which on 32-bit means similar
|
|
semantics as on 64-bit: edx can be used for a second return value
|
|
(i.e. covering integer and structure sizes up to 64 bits) - after that
|
|
it gets more complex and more expensive: 3-word or larger struct returns
|
|
get done in the caller's frame and the pointer to the return struct goes
|
|
into regparm0, i.e. eax - the other arguments shift up and the
|
|
function's register parameters degenerate to regparm=2 in essence.
|
|
|
|
*/
|
|
|
|
|
|
/*
|
|
* 64-bit system call stack frame layout defines and helpers, for
|
|
* assembly code (note that the seemingly unnecessary parentheses
|
|
* are to prevent cpp from inserting spaces in expressions that get
|
|
* passed to macros):
|
|
*/
|
|
|
|
#define R15 (0)
|
|
#define R14 (8)
|
|
#define R13 (16)
|
|
#define R12 (24)
|
|
#define RBP (32)
|
|
#define RBX (40)
|
|
|
|
/* arguments: interrupts/non tracing syscalls only save up to here: */
|
|
#define R11 (48)
|
|
#define R10 (56)
|
|
#define R9 (64)
|
|
#define R8 (72)
|
|
#define RAX (80)
|
|
#define RCX (88)
|
|
#define RDX (96)
|
|
#define RSI (104)
|
|
#define RDI (112)
|
|
#define ORIG_RAX (120) /* + error_code */
|
|
/* end of arguments */
|
|
|
|
/* cpu exception frame or undefined in case of fast syscall: */
|
|
#define RIP (128)
|
|
#define CS (136)
|
|
#define EFLAGS (144)
|
|
#define RSP (152)
|
|
#define SS (160)
|
|
|
|
#define ARGOFFSET R11
|
|
#define SWFRAME ORIG_RAX
|
|
|
|
.macro SAVE_ARGS addskip=0, norcx=0, nor891011=0
|
|
subq $9*8+\addskip, %rsp
|
|
CFI_ADJUST_CFA_OFFSET 9*8+\addskip
|
|
movq %rdi, 8*8(%rsp)
|
|
CFI_REL_OFFSET rdi, 8*8
|
|
movq %rsi, 7*8(%rsp)
|
|
CFI_REL_OFFSET rsi, 7*8
|
|
movq %rdx, 6*8(%rsp)
|
|
CFI_REL_OFFSET rdx, 6*8
|
|
.if \norcx
|
|
.else
|
|
movq %rcx, 5*8(%rsp)
|
|
CFI_REL_OFFSET rcx, 5*8
|
|
.endif
|
|
movq %rax, 4*8(%rsp)
|
|
CFI_REL_OFFSET rax, 4*8
|
|
.if \nor891011
|
|
.else
|
|
movq %r8, 3*8(%rsp)
|
|
CFI_REL_OFFSET r8, 3*8
|
|
movq %r9, 2*8(%rsp)
|
|
CFI_REL_OFFSET r9, 2*8
|
|
movq %r10, 1*8(%rsp)
|
|
CFI_REL_OFFSET r10, 1*8
|
|
movq %r11, (%rsp)
|
|
CFI_REL_OFFSET r11, 0*8
|
|
.endif
|
|
.endm
|
|
|
|
#define ARG_SKIP (9*8)
|
|
|
|
.macro RESTORE_ARGS skiprax=0, addskip=0, skiprcx=0, skipr11=0, \
|
|
skipr8910=0, skiprdx=0
|
|
.if \skipr11
|
|
.else
|
|
movq (%rsp), %r11
|
|
CFI_RESTORE r11
|
|
.endif
|
|
.if \skipr8910
|
|
.else
|
|
movq 1*8(%rsp), %r10
|
|
CFI_RESTORE r10
|
|
movq 2*8(%rsp), %r9
|
|
CFI_RESTORE r9
|
|
movq 3*8(%rsp), %r8
|
|
CFI_RESTORE r8
|
|
.endif
|
|
.if \skiprax
|
|
.else
|
|
movq 4*8(%rsp), %rax
|
|
CFI_RESTORE rax
|
|
.endif
|
|
.if \skiprcx
|
|
.else
|
|
movq 5*8(%rsp), %rcx
|
|
CFI_RESTORE rcx
|
|
.endif
|
|
.if \skiprdx
|
|
.else
|
|
movq 6*8(%rsp), %rdx
|
|
CFI_RESTORE rdx
|
|
.endif
|
|
movq 7*8(%rsp), %rsi
|
|
CFI_RESTORE rsi
|
|
movq 8*8(%rsp), %rdi
|
|
CFI_RESTORE rdi
|
|
.if ARG_SKIP+\addskip > 0
|
|
addq $ARG_SKIP+\addskip, %rsp
|
|
CFI_ADJUST_CFA_OFFSET -(ARG_SKIP+\addskip)
|
|
.endif
|
|
.endm
|
|
|
|
.macro LOAD_ARGS offset, skiprax=0
|
|
movq \offset(%rsp), %r11
|
|
movq \offset+8(%rsp), %r10
|
|
movq \offset+16(%rsp), %r9
|
|
movq \offset+24(%rsp), %r8
|
|
movq \offset+40(%rsp), %rcx
|
|
movq \offset+48(%rsp), %rdx
|
|
movq \offset+56(%rsp), %rsi
|
|
movq \offset+64(%rsp), %rdi
|
|
.if \skiprax
|
|
.else
|
|
movq \offset+72(%rsp), %rax
|
|
.endif
|
|
.endm
|
|
|
|
#define REST_SKIP (6*8)
|
|
|
|
.macro SAVE_REST
|
|
subq $REST_SKIP, %rsp
|
|
CFI_ADJUST_CFA_OFFSET REST_SKIP
|
|
movq %rbx, 5*8(%rsp)
|
|
CFI_REL_OFFSET rbx, 5*8
|
|
movq %rbp, 4*8(%rsp)
|
|
CFI_REL_OFFSET rbp, 4*8
|
|
movq %r12, 3*8(%rsp)
|
|
CFI_REL_OFFSET r12, 3*8
|
|
movq %r13, 2*8(%rsp)
|
|
CFI_REL_OFFSET r13, 2*8
|
|
movq %r14, 1*8(%rsp)
|
|
CFI_REL_OFFSET r14, 1*8
|
|
movq %r15, (%rsp)
|
|
CFI_REL_OFFSET r15, 0*8
|
|
.endm
|
|
|
|
.macro RESTORE_REST
|
|
movq (%rsp), %r15
|
|
CFI_RESTORE r15
|
|
movq 1*8(%rsp), %r14
|
|
CFI_RESTORE r14
|
|
movq 2*8(%rsp), %r13
|
|
CFI_RESTORE r13
|
|
movq 3*8(%rsp), %r12
|
|
CFI_RESTORE r12
|
|
movq 4*8(%rsp), %rbp
|
|
CFI_RESTORE rbp
|
|
movq 5*8(%rsp), %rbx
|
|
CFI_RESTORE rbx
|
|
addq $REST_SKIP, %rsp
|
|
CFI_ADJUST_CFA_OFFSET -(REST_SKIP)
|
|
.endm
|
|
|
|
.macro SAVE_ALL
|
|
SAVE_ARGS
|
|
SAVE_REST
|
|
.endm
|
|
|
|
.macro RESTORE_ALL addskip=0
|
|
RESTORE_REST
|
|
RESTORE_ARGS 0, \addskip
|
|
.endm
|
|
|
|
.macro icebp
|
|
.byte 0xf1
|
|
.endm
|
|
|