1/*
  2 * __get_user functions.
  3 *
  4 * (C) Copyright 1998 Linus Torvalds
  5 * (C) Copyright 2005 Andi Kleen
  6 * (C) Copyright 2008 Glauber Costa
  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 *
 17 * Inputs:	%[r|e]ax contains the address.
 18 *		The register is modified, but all changes are undone
 19 *		before returning because the C code doesn't know about it.
 20 *
 21 * Outputs:	%[r|e]ax is error code (0 or -EFAULT)
 22 *		%[r|e]dx contains zero-extended value
 
 23 *
 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>
 30#include <asm/dwarf2.h>
 31#include <asm/page_types.h>
 32#include <asm/errno.h>
 33#include <asm/asm-offsets.h>
 34#include <asm/thread_info.h>
 35#include <asm/asm.h>
 
 36
 37	.text
 38ENTRY(__get_user_1)
 39	CFI_STARTPROC
 40	GET_THREAD_INFO(%_ASM_DX)
 41	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 42	jae bad_get_user
 431:	movzb (%_ASM_AX),%edx
 
 44	xor %eax,%eax
 
 45	ret
 46	CFI_ENDPROC
 47ENDPROC(__get_user_1)
 48
 49ENTRY(__get_user_2)
 50	CFI_STARTPROC
 51	add $1,%_ASM_AX
 52	jc bad_get_user
 53	GET_THREAD_INFO(%_ASM_DX)
 54	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 55	jae bad_get_user
 
 562:	movzwl -1(%_ASM_AX),%edx
 57	xor %eax,%eax
 
 58	ret
 59	CFI_ENDPROC
 60ENDPROC(__get_user_2)
 61
 62ENTRY(__get_user_4)
 63	CFI_STARTPROC
 64	add $3,%_ASM_AX
 65	jc bad_get_user
 66	GET_THREAD_INFO(%_ASM_DX)
 67	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 68	jae bad_get_user
 693:	mov -3(%_ASM_AX),%edx
 
 70	xor %eax,%eax
 
 71	ret
 72	CFI_ENDPROC
 73ENDPROC(__get_user_4)
 74
 75#ifdef CONFIG_X86_64
 76ENTRY(__get_user_8)
 77	CFI_STARTPROC
 78	add $7,%_ASM_AX
 79	jc bad_get_user
 80	GET_THREAD_INFO(%_ASM_DX)
 81	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 82	jae	bad_get_user
 834:	movq -7(%_ASM_AX),%_ASM_DX
 
 84	xor %eax,%eax
 
 
 
 
 
 
 
 
 
 
 
 
 
 85	ret
 86	CFI_ENDPROC
 87ENDPROC(__get_user_8)
 88#endif
 
 
 89
 90bad_get_user:
 91	CFI_STARTPROC
 92	xor %edx,%edx
 93	mov $(-EFAULT),%_ASM_AX
 
 94	ret
 95	CFI_ENDPROC
 96END(bad_get_user)
 97
 98.section __ex_table,"a"
 99	_ASM_PTR 1b,bad_get_user
100	_ASM_PTR 2b,bad_get_user
101	_ASM_PTR 3b,bad_get_user
 
 
 
 
 
 
 
 
 
102#ifdef CONFIG_X86_64
103	_ASM_PTR 4b,bad_get_user
 
 
 
104#endif

  1/*
  2 * __get_user functions.
  3 *
  4 * (C) Copyright 1998 Linus Torvalds
  5 * (C) Copyright 2005 Andi Kleen
  6 * (C) Copyright 2008 Glauber Costa
  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 *
 17 * Inputs:	%[r|e]ax contains the address.
 
 
 18 *
 19 * Outputs:	%[r|e]ax is error code (0 or -EFAULT)
 20 *		%[r|e]dx contains zero-extended value
 21 *		%ecx contains the high half for 32-bit __get_user_8
 22 *
 23 *
 24 * These functions should not modify any other registers,
 25 * as they get called from within inline assembly.
 26 */
 27
 28#include <linux/linkage.h>
 
 29#include <asm/page_types.h>
 30#include <asm/errno.h>
 31#include <asm/asm-offsets.h>
 32#include <asm/thread_info.h>
 33#include <asm/asm.h>
 34#include <asm/smap.h>
 35
 36	.text
 37ENTRY(__get_user_1)
 
 38	GET_THREAD_INFO(%_ASM_DX)
 39	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 40	jae bad_get_user
 41	ASM_STAC
 421:	movzbl (%_ASM_AX),%edx
 43	xor %eax,%eax
 44	ASM_CLAC
 45	ret
 
 46ENDPROC(__get_user_1)
 47
 48ENTRY(__get_user_2)
 
 49	add $1,%_ASM_AX
 50	jc bad_get_user
 51	GET_THREAD_INFO(%_ASM_DX)
 52	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 53	jae bad_get_user
 54	ASM_STAC
 552:	movzwl -1(%_ASM_AX),%edx
 56	xor %eax,%eax
 57	ASM_CLAC
 58	ret
 
 59ENDPROC(__get_user_2)
 60
 61ENTRY(__get_user_4)
 
 62	add $3,%_ASM_AX
 63	jc bad_get_user
 64	GET_THREAD_INFO(%_ASM_DX)
 65	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 66	jae bad_get_user
 67	ASM_STAC
 683:	movl -3(%_ASM_AX),%edx
 69	xor %eax,%eax
 70	ASM_CLAC
 71	ret
 
 72ENDPROC(__get_user_4)
 73
 
 74ENTRY(__get_user_8)
 75#ifdef CONFIG_X86_64
 76	add $7,%_ASM_AX
 77	jc bad_get_user
 78	GET_THREAD_INFO(%_ASM_DX)
 79	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 80	jae bad_get_user
 81	ASM_STAC
 824:	movq -7(%_ASM_AX),%rdx
 83	xor %eax,%eax
 84	ASM_CLAC
 85	ret
 86#else
 87	add $7,%_ASM_AX
 88	jc bad_get_user_8
 89	GET_THREAD_INFO(%_ASM_DX)
 90	cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
 91	jae bad_get_user_8
 92	ASM_STAC
 934:	movl -7(%_ASM_AX),%edx
 945:	movl -3(%_ASM_AX),%ecx
 95	xor %eax,%eax
 96	ASM_CLAC
 97	ret
 
 
 98#endif
 99ENDPROC(__get_user_8)
100
101
102bad_get_user:
 
103	xor %edx,%edx
104	mov $(-EFAULT),%_ASM_AX
105	ASM_CLAC
106	ret
 
107END(bad_get_user)
108
109#ifdef CONFIG_X86_32
110bad_get_user_8:
111	xor %edx,%edx
112	xor %ecx,%ecx
113	mov $(-EFAULT),%_ASM_AX
114	ASM_CLAC
115	ret
116END(bad_get_user_8)
117#endif
118
119	_ASM_EXTABLE(1b,bad_get_user)
120	_ASM_EXTABLE(2b,bad_get_user)
121	_ASM_EXTABLE(3b,bad_get_user)
122#ifdef CONFIG_X86_64
123	_ASM_EXTABLE(4b,bad_get_user)
124#else
125	_ASM_EXTABLE(4b,bad_get_user_8)
126	_ASM_EXTABLE(5b,bad_get_user_8)
127#endif