[linux-2.6-block.git] / arch / x86 / entry / calling.h

#include <linux/jump_label.h>

/*

 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.

*/

#ifdef CONFIG_X86_64

/*
 * 64-bit system call stack frame layout defines and helpers,
 * for assembly code:
 */

/* The layout forms the "struct pt_regs" on the stack: */
/*
 * C ABI says these regs are callee-preserved. They aren't saved on kernel entry
 * unless syscall needs a complete, fully filled "struct pt_regs".
 */
#define R15		0*8
#define R14		1*8
#define R13		2*8
#define R12		3*8
#define RBP		4*8
#define RBX		5*8
/* These regs are callee-clobbered. Always saved on kernel entry. */
#define R11		6*8
#define R10		7*8
#define R9		8*8
#define R8		9*8
#define RAX		10*8
#define RCX		11*8
#define RDX		12*8
#define RSI		13*8
#define RDI		14*8
/*
 * On syscall entry, this is syscall#. On CPU exception, this is error code.
 * On hw interrupt, it's IRQ number:
 */
#define ORIG_RAX	15*8
/* Return frame for iretq */
#define RIP		16*8
#define CS		17*8
#define EFLAGS		18*8
#define RSP		19*8
#define SS		20*8

#define SIZEOF_PTREGS	21*8

	.macro ALLOC_PT_GPREGS_ON_STACK addskip=0
	addq	$-(15*8+\addskip), %rsp
	.endm

	.macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1
	.if \r11
	movq %r11, 6*8+\offset(%rsp)
	.endif
	.if \r8910
	movq %r10, 7*8+\offset(%rsp)
	movq %r9,  8*8+\offset(%rsp)
	movq %r8,  9*8+\offset(%rsp)
	.endif
	.if \rax
	movq %rax, 10*8+\offset(%rsp)
	.endif
	.if \rcx
	movq %rcx, 11*8+\offset(%rsp)
	.endif
	movq %rdx, 12*8+\offset(%rsp)
	movq %rsi, 13*8+\offset(%rsp)
	movq %rdi, 14*8+\offset(%rsp)
	.endm
	.macro SAVE_C_REGS offset=0
	SAVE_C_REGS_HELPER \offset, 1, 1, 1, 1
	.endm
	.macro SAVE_C_REGS_EXCEPT_RAX_RCX offset=0
	SAVE_C_REGS_HELPER \offset, 0, 0, 1, 1
	.endm
	.macro SAVE_C_REGS_EXCEPT_R891011
	SAVE_C_REGS_HELPER 0, 1, 1, 0, 0
	.endm
	.macro SAVE_C_REGS_EXCEPT_RCX_R891011
	SAVE_C_REGS_HELPER 0, 1, 0, 0, 0
	.endm
	.macro SAVE_C_REGS_EXCEPT_RAX_RCX_R11
	SAVE_C_REGS_HELPER 0, 0, 0, 1, 0
	.endm

	.macro SAVE_EXTRA_REGS offset=0
	movq %r15, 0*8+\offset(%rsp)
	movq %r14, 1*8+\offset(%rsp)
	movq %r13, 2*8+\offset(%rsp)
	movq %r12, 3*8+\offset(%rsp)
	movq %rbp, 4*8+\offset(%rsp)
	movq %rbx, 5*8+\offset(%rsp)
	.endm

	.macro RESTORE_EXTRA_REGS offset=0
	movq 0*8+\offset(%rsp), %r15
	movq 1*8+\offset(%rsp), %r14
	movq 2*8+\offset(%rsp), %r13
	movq 3*8+\offset(%rsp), %r12
	movq 4*8+\offset(%rsp), %rbp
	movq 5*8+\offset(%rsp), %rbx
	.endm

	.macro ZERO_EXTRA_REGS
	xorl	%r15d, %r15d
	xorl	%r14d, %r14d
	xorl	%r13d, %r13d
	xorl	%r12d, %r12d
	xorl	%ebp, %ebp
	xorl	%ebx, %ebx
	.endm

	.macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1
	.if \rstor_r11
	movq 6*8(%rsp), %r11
	.endif
	.if \rstor_r8910
	movq 7*8(%rsp), %r10
	movq 8*8(%rsp), %r9
	movq 9*8(%rsp), %r8
	.endif
	.if \rstor_rax
	movq 10*8(%rsp), %rax
	.endif
	.if \rstor_rcx
	movq 11*8(%rsp), %rcx
	.endif
	.if \rstor_rdx
	movq 12*8(%rsp), %rdx
	.endif
	movq 13*8(%rsp), %rsi
	movq 14*8(%rsp), %rdi
	.endm
	.macro RESTORE_C_REGS
	RESTORE_C_REGS_HELPER 1,1,1,1,1
	.endm
	.macro RESTORE_C_REGS_EXCEPT_RAX
	RESTORE_C_REGS_HELPER 0,1,1,1,1
	.endm
	.macro RESTORE_C_REGS_EXCEPT_RCX
	RESTORE_C_REGS_HELPER 1,0,1,1,1
	.endm
	.macro RESTORE_C_REGS_EXCEPT_R11
	RESTORE_C_REGS_HELPER 1,1,0,1,1
	.endm
	.macro RESTORE_C_REGS_EXCEPT_RCX_R11
	RESTORE_C_REGS_HELPER 1,0,0,1,1
	.endm

	.macro REMOVE_PT_GPREGS_FROM_STACK addskip=0
	subq $-(15*8+\addskip), %rsp
	.endm

	.macro icebp
	.byte 0xf1
	.endm

#endif /* CONFIG_X86_64 */

/*
 * This does 'call enter_from_user_mode' unless we can avoid it based on
 * kernel config or using the static jump infrastructure.
 */
.macro CALL_enter_from_user_mode
#ifdef CONFIG_CONTEXT_TRACKING
#ifdef HAVE_JUMP_LABEL
	STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0
#endif
	call enter_from_user_mode
.Lafter_call_\@:
#endif
.endm
Commit	Line	Data
478dc89c AL	1	#include <linux/jump_label.h>
478dc89c AL	2
0c2bd5a5	3	/*
063f8913 IM	4
	5	x86 function call convention, 64-bit:
	6	-------------------------------------
	7	arguments \| callee-saved \| extra caller-saved \| return
	8	[callee-clobbered] \| \| [callee-clobbered] \|
	9	---------------------------------------------------------------------------
	10	rdi rsi rdx rcx r8-9 \| rbx rbp [] r12-15 \| r10-11 \| rax, rdx [*]
	11
	12	( rsp is obviously invariant across normal function calls. (gcc can 'merge'
	13	functions when it sees tail-call optimization possibilities) rflags is
	14	clobbered. Leftover arguments are passed over the stack frame.)
	15
	16	[*] In the frame-pointers case rbp is fixed to the stack frame.
	17
	18	[**] for struct return values wider than 64 bits the return convention is a
	19	bit more complex: up to 128 bits width we return small structures
	20	straight in rax, rdx. For structures larger than that (3 words or
	21	larger) the caller puts a pointer to an on-stack return struct
	22	[allocated in the caller's stack frame] into the first argument - i.e.
	23	into rdi. All other arguments shift up by one in this case.
	24	Fortunately this case is rare in the kernel.
	25
	26	For 32-bit we have the following conventions - kernel is built with
	27	-mregparm=3 and -freg-struct-return:
	28
	29	x86 function calling convention, 32-bit:
	30	----------------------------------------
	31	arguments \| callee-saved \| extra caller-saved \| return
	32	[callee-clobbered] \| \| [callee-clobbered] \|
	33	-------------------------------------------------------------------------
	34	eax edx ecx \| ebx edi esi ebp [] \| <none> \| eax, edx [*]
	35
	36	( here too esp is obviously invariant across normal function calls. eflags
	37	is clobbered. Leftover arguments are passed over the stack frame. )
	38
	39	[*] In the frame-pointers case ebp is fixed to the stack frame.
	40
	41	[**] We build with -freg-struct-return, which on 32-bit means similar
	42	semantics as on 64-bit: edx can be used for a second return value
	43	(i.e. covering integer and structure sizes up to 64 bits) - after that
	44	it gets more complex and more expensive: 3-word or larger struct returns
	45	get done in the caller's frame and the pointer to the return struct goes
	46	into regparm0, i.e. eax - the other arguments shift up and the
	47	function's register parameters degenerate to regparm=2 in essence.
	48
	49	*/
	50
1a338ac3 PZ	51	#ifdef CONFIG_X86_64
1a338ac3 PZ	52
063f8913	53	/*
1b2b23d8 TG	54	* 64-bit system call stack frame layout defines and helpers,
1b2b23d8 TG	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
911d2bb5 DV	92
76f5df43	93	.macro ALLOC_PT_GPREGS_ON_STACK addskip=0
2bf557ea	94	addq $-(15*8+\addskip), %rsp
76f5df43	95	.endm
a268fcfa	96
29722cd4 DV	97	.macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1
29722cd4 DV	98	.if \r11
131484c8	99	movq %r11, 6*8+\offset(%rsp)
29722cd4 DV	100	.endif
29722cd4 DV	101	.if \r8910
131484c8 IM	102	movq %r10, 7*8+\offset(%rsp)
	103	movq %r9, 8*8+\offset(%rsp)
	104	movq %r8, 9*8+\offset(%rsp)
54eea995	105	.endif
76f5df43	106	.if \rax
131484c8	107	movq %rax, 10*8+\offset(%rsp)
76f5df43 DV	108	.endif
76f5df43 DV	109	.if \rcx
131484c8	110	movq %rcx, 11*8+\offset(%rsp)
1da177e4	111	.endif
131484c8 IM	112	movq %rdx, 12*8+\offset(%rsp)
	113	movq %rsi, 13*8+\offset(%rsp)
	114	movq %rdi, 14*8+\offset(%rsp)
76f5df43 DV	115	.endm
76f5df43 DV	116	.macro SAVE_C_REGS offset=0
29722cd4	117	SAVE_C_REGS_HELPER \offset, 1, 1, 1, 1
76f5df43 DV	118	.endm
76f5df43 DV	119	.macro SAVE_C_REGS_EXCEPT_RAX_RCX offset=0
29722cd4	120	SAVE_C_REGS_HELPER \offset, 0, 0, 1, 1
76f5df43 DV	121	.endm
76f5df43 DV	122	.macro SAVE_C_REGS_EXCEPT_R891011
29722cd4	123	SAVE_C_REGS_HELPER 0, 1, 1, 0, 0
76f5df43 DV	124	.endm
76f5df43 DV	125	.macro SAVE_C_REGS_EXCEPT_RCX_R891011
29722cd4 DV	126	SAVE_C_REGS_HELPER 0, 1, 0, 0, 0
	127	.endm
	128	.macro SAVE_C_REGS_EXCEPT_RAX_RCX_R11
	129	SAVE_C_REGS_HELPER 0, 0, 0, 1, 0
76f5df43	130	.endm
a268fcfa	131
76f5df43	132	.macro SAVE_EXTRA_REGS offset=0
131484c8 IM	133	movq %r15, 0*8+\offset(%rsp)
	134	movq %r14, 1*8+\offset(%rsp)
	135	movq %r13, 2*8+\offset(%rsp)
	136	movq %r12, 3*8+\offset(%rsp)
	137	movq %rbp, 4*8+\offset(%rsp)
	138	movq %rbx, 5*8+\offset(%rsp)
76f5df43	139	.endm
1da177e4	140
76f5df43	141	.macro RESTORE_EXTRA_REGS offset=0
131484c8 IM	142	movq 0*8+\offset(%rsp), %r15
	143	movq 1*8+\offset(%rsp), %r14
	144	movq 2*8+\offset(%rsp), %r13
	145	movq 3*8+\offset(%rsp), %r12
	146	movq 4*8+\offset(%rsp), %rbp
	147	movq 5*8+\offset(%rsp), %rbx
76f5df43	148	.endm
0c2bd5a5	149
fc3e958a DV	150	.macro ZERO_EXTRA_REGS
	151	xorl %r15d, %r15d
	152	xorl %r14d, %r14d
	153	xorl %r13d, %r13d
	154	xorl %r12d, %r12d
	155	xorl %ebp, %ebp
	156	xorl %ebx, %ebx
	157	.endm
	158
76f5df43	159	.macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1
838feb47	160	.if \rstor_r11
131484c8	161	movq 6*8(%rsp), %r11
1da177e4	162	.endif
838feb47	163	.if \rstor_r8910
131484c8 IM	164	movq 7*8(%rsp), %r10
	165	movq 8*8(%rsp), %r9
	166	movq 9*8(%rsp), %r8
1da177e4	167	.endif
838feb47	168	.if \rstor_rax
131484c8	169	movq 10*8(%rsp), %rax
1da177e4	170	.endif
838feb47	171	.if \rstor_rcx
131484c8	172	movq 11*8(%rsp), %rcx
1da177e4	173	.endif
838feb47	174	.if \rstor_rdx
131484c8	175	movq 12*8(%rsp), %rdx
1da177e4	176	.endif
131484c8 IM	177	movq 13*8(%rsp), %rsi
131484c8 IM	178	movq 14*8(%rsp), %rdi
0c2bd5a5	179	.endm
76f5df43 DV	180	.macro RESTORE_C_REGS
76f5df43 DV	181	RESTORE_C_REGS_HELPER 1,1,1,1,1
1da177e4	182	.endm
76f5df43 DV	183	.macro RESTORE_C_REGS_EXCEPT_RAX
76f5df43 DV	184	RESTORE_C_REGS_HELPER 0,1,1,1,1
0c2bd5a5	185	.endm
76f5df43 DV	186	.macro RESTORE_C_REGS_EXCEPT_RCX
76f5df43 DV	187	RESTORE_C_REGS_HELPER 1,0,1,1,1
1da177e4	188	.endm
d441c1f2 DV	189	.macro RESTORE_C_REGS_EXCEPT_R11
	190	RESTORE_C_REGS_HELPER 1,1,0,1,1
	191	.endm
29722cd4 DV	192	.macro RESTORE_C_REGS_EXCEPT_RCX_R11
	193	RESTORE_C_REGS_HELPER 1,0,0,1,1
	194	.endm
0c2bd5a5	195
76f5df43	196	.macro REMOVE_PT_GPREGS_FROM_STACK addskip=0
2bf557ea	197	subq $-(15*8+\addskip), %rsp
1da177e4 LT	198	.endm
	199
	200	.macro icebp
	201	.byte 0xf1
	202	.endm
1a338ac3	203
1a338ac3 PZ	204	#endif /* CONFIG_X86_64 */
1a338ac3 PZ	205
478dc89c AL	206	/*
	207	* This does 'call enter_from_user_mode' unless we can avoid it based on
	208	* kernel config or using the static jump infrastructure.
	209	*/
	210	.macro CALL_enter_from_user_mode
	211	#ifdef CONFIG_CONTEXT_TRACKING
	212	#ifdef HAVE_JUMP_LABEL
	213	STATIC_JUMP_IF_FALSE .Lafter_call_\@, context_tracking_enabled, def=0
	214	#endif
	215	call enter_from_user_mode
	216	.Lafter_call_\@:
	217	#endif
	218	.endm