[net-next-2.6.git] / arch / x86 / lib / getuser.S

/*
 * __get_user functions.
 *
 * (C) Copyright 1998 Linus Torvalds
 * (C) Copyright 2005 Andi Kleen
 * (C) Copyright 2008 Glauber Costa
 *
 * These functions have a non-standard call interface
 * to make them more efficient, especially as they
 * return an error value in addition to the "real"
 * return value.
 */

/*
 * __get_user_X
 *
 * Inputs:	%[r|e]ax contains the address.
 *		The register is modified, but all changes are undone
 *		before returning because the C code doesn't know about it.
 *
 * Outputs:	%[r|e]ax is error code (0 or -EFAULT)
 *		%[r|e]dx contains zero-extended value
 *
 *
 * These functions should not modify any other registers,
 * as they get called from within inline assembly.
 */

#include <linux/linkage.h>
#include <asm/dwarf2.h>
#include <asm/page_types.h>
#include <asm/errno.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/asm.h>

	.text
ENTRY(__get_user_1)
	CFI_STARTPROC
	GET_THREAD_INFO(%_ASM_DX)
	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
	jae bad_get_user
1:	movzb (%_ASM_AX),%edx
	xor %eax,%eax
	ret
	CFI_ENDPROC
ENDPROC(__get_user_1)

ENTRY(__get_user_2)
	CFI_STARTPROC
	add $1,%_ASM_AX
	jc bad_get_user
	GET_THREAD_INFO(%_ASM_DX)
	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
	jae bad_get_user
2:	movzwl -1(%_ASM_AX),%edx
	xor %eax,%eax
	ret
	CFI_ENDPROC
ENDPROC(__get_user_2)

ENTRY(__get_user_4)
	CFI_STARTPROC
	add $3,%_ASM_AX
	jc bad_get_user
	GET_THREAD_INFO(%_ASM_DX)
	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
	jae bad_get_user
3:	mov -3(%_ASM_AX),%edx
	xor %eax,%eax
	ret
	CFI_ENDPROC
ENDPROC(__get_user_4)

#ifdef CONFIG_X86_64
ENTRY(__get_user_8)
	CFI_STARTPROC
	add $7,%_ASM_AX
	jc bad_get_user
	GET_THREAD_INFO(%_ASM_DX)
	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
	jae	bad_get_user
4:	movq -7(%_ASM_AX),%_ASM_DX
	xor %eax,%eax
	ret
	CFI_ENDPROC
ENDPROC(__get_user_8)
#endif

bad_get_user:
	CFI_STARTPROC
	xor %edx,%edx
	mov $(-EFAULT),%_ASM_AX
	ret
	CFI_ENDPROC
END(bad_get_user)

.section __ex_table,"a"
	_ASM_PTR 1b,bad_get_user
	_ASM_PTR 2b,bad_get_user
	_ASM_PTR 3b,bad_get_user
#ifdef CONFIG_X86_64
	_ASM_PTR 4b,bad_get_user
#endif
Commit	Line	Data
1da177e4 LT	1	/*
	2	* __get_user functions.
	3	*
	4	* (C) Copyright 1998 Linus Torvalds
	5	* (C) Copyright 2005 Andi Kleen
6c2d4586	6	* (C) Copyright 2008 Glauber Costa
1da177e4 LT	7	*
	8	* These functions have a non-standard call interface
	9	* to make them more efficient, especially as they
	10	* return an error value in addition to the "real"
	11	* return value.
	12	*/
	13
	14	/*
	15	* __get_user_X
	16	*
6c2d4586	17	* Inputs: %[r\|e]ax contains the address.
1da177e4 LT	18	* The register is modified, but all changes are undone
	19	* before returning because the C code doesn't know about it.
	20	*
6c2d4586 GC	21	* Outputs: %[r\|e]ax is error code (0 or -EFAULT)
	22	* %[r\|e]dx contains zero-extended value
	23	*
1da177e4 LT	24	*
	25	* These functions should not modify any other registers,
	26	* as they get called from within inline assembly.
	27	*/
	28
	29	#include <linux/linkage.h>
8d379dad	30	#include <asm/dwarf2.h>
0341c14d	31	#include <asm/page_types.h>
1da177e4	32	#include <asm/errno.h>
e2d5df93	33	#include <asm/asm-offsets.h>
1da177e4	34	#include <asm/thread_info.h>
40faf463	35	#include <asm/asm.h>
1da177e4 LT	36
1da177e4 LT	37	.text
8d379dad JB	38	ENTRY(__get_user_1)
8d379dad JB	39	CFI_STARTPROC
40faf463 GC	40	GET_THREAD_INFO(%_ASM_DX)
40faf463 GC	41	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
1da177e4	42	jae bad_get_user
40faf463	43	1: movzb (%_ASM_AX),%edx
ef8c1a2d	44	xor %eax,%eax
1da177e4	45	ret
8d379dad JB	46	CFI_ENDPROC
8d379dad JB	47	ENDPROC(__get_user_1)
1da177e4	48
8d379dad JB	49	ENTRY(__get_user_2)
8d379dad JB	50	CFI_STARTPROC
40faf463	51	add $1,%_ASM_AX
92628753	52	jc bad_get_user
40faf463 GC	53	GET_THREAD_INFO(%_ASM_DX)
40faf463 GC	54	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
92628753	55	jae bad_get_user
40faf463	56	2: movzwl -1(%_ASM_AX),%edx
ef8c1a2d	57	xor %eax,%eax
1da177e4	58	ret
8d379dad JB	59	CFI_ENDPROC
8d379dad JB	60	ENDPROC(__get_user_2)
1da177e4	61
8d379dad JB	62	ENTRY(__get_user_4)
8d379dad JB	63	CFI_STARTPROC
40faf463	64	add $3,%_ASM_AX
92628753	65	jc bad_get_user
40faf463 GC	66	GET_THREAD_INFO(%_ASM_DX)
40faf463 GC	67	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
92628753	68	jae bad_get_user
40faf463	69	3: mov -3(%_ASM_AX),%edx
ef8c1a2d	70	xor %eax,%eax
1da177e4	71	ret
8d379dad JB	72	CFI_ENDPROC
8d379dad JB	73	ENDPROC(__get_user_4)
1da177e4	74
6c2d4586	75	#ifdef CONFIG_X86_64
8d379dad JB	76	ENTRY(__get_user_8)
8d379dad JB	77	CFI_STARTPROC
40faf463	78	add $7,%_ASM_AX
92628753	79	jc bad_get_user
40faf463 GC	80	GET_THREAD_INFO(%_ASM_DX)
40faf463 GC	81	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
92628753	82	jae bad_get_user
40faf463	83	4: movq -7(%_ASM_AX),%_ASM_DX
ef8c1a2d	84	xor %eax,%eax
1da177e4	85	ret
8d379dad JB	86	CFI_ENDPROC
8d379dad JB	87	ENDPROC(__get_user_8)
6c2d4586	88	#endif
1da177e4 LT	89
1da177e4 LT	90	bad_get_user:
8d379dad	91	CFI_STARTPROC
ef8c1a2d	92	xor %edx,%edx
40faf463	93	mov $(-EFAULT),%_ASM_AX
1da177e4	94	ret
8d379dad JB	95	CFI_ENDPROC
8d379dad JB	96	END(bad_get_user)
1da177e4 LT	97
1da177e4 LT	98	.section __ex_table,"a"
87e2f1e7 GC	99	_ASM_PTR 1b,bad_get_user
	100	_ASM_PTR 2b,bad_get_user
	101	_ASM_PTR 3b,bad_get_user
6c2d4586	102	#ifdef CONFIG_X86_64
87e2f1e7	103	_ASM_PTR 4b,bad_get_user
6c2d4586	104	#endif