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/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * __get_user functions.
  4 *
  5 * (C) Copyright 1998 Linus Torvalds
  6 * (C) Copyright 2005 Andi Kleen
  7 * (C) Copyright 2008 Glauber Costa
  8 *
  9 * These functions have a non-standard call interface
 10 * to make them more efficient, especially as they
 11 * return an error value in addition to the "real"
 12 * return value.
 13 */
 14
 15/*
 16 * __get_user_X
 17 *
 18 * Inputs:	%[r|e]ax contains the address.
 
 
 19 *
 20 * Outputs:	%[r|e]ax is error code (0 or -EFAULT)
 21 *		%[r|e]dx contains zero-extended value
 22 *		%ecx contains the high half for 32-bit __get_user_8
 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/page_types.h>
 31#include <asm/errno.h>
 32#include <asm/asm-offsets.h>
 33#include <asm/thread_info.h>
 34#include <asm/asm.h>
 35#include <asm/smap.h>
 36#include <asm/export.h>
 37
 38	.text
 39ENTRY(__get_user_1)
 40	mov PER_CPU_VAR(current_task), %_ASM_DX
 41	cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
 
 42	jae bad_get_user
 43	sbb %_ASM_DX, %_ASM_DX		/* array_index_mask_nospec() */
 44	and %_ASM_DX, %_ASM_AX
 45	ASM_STAC
 461:	movzbl (%_ASM_AX),%edx
 47	xor %eax,%eax
 48	ASM_CLAC
 49	ret
 
 50ENDPROC(__get_user_1)
 51EXPORT_SYMBOL(__get_user_1)
 52
 53ENTRY(__get_user_2)
 
 54	add $1,%_ASM_AX
 55	jc bad_get_user
 56	mov PER_CPU_VAR(current_task), %_ASM_DX
 57	cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
 58	jae bad_get_user
 59	sbb %_ASM_DX, %_ASM_DX		/* array_index_mask_nospec() */
 60	and %_ASM_DX, %_ASM_AX
 61	ASM_STAC
 622:	movzwl -1(%_ASM_AX),%edx
 63	xor %eax,%eax
 64	ASM_CLAC
 65	ret
 
 66ENDPROC(__get_user_2)
 67EXPORT_SYMBOL(__get_user_2)
 68
 69ENTRY(__get_user_4)
 
 70	add $3,%_ASM_AX
 71	jc bad_get_user
 72	mov PER_CPU_VAR(current_task), %_ASM_DX
 73	cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
 74	jae bad_get_user
 75	sbb %_ASM_DX, %_ASM_DX		/* array_index_mask_nospec() */
 76	and %_ASM_DX, %_ASM_AX
 77	ASM_STAC
 783:	movl -3(%_ASM_AX),%edx
 79	xor %eax,%eax
 80	ASM_CLAC
 81	ret
 
 82ENDPROC(__get_user_4)
 83EXPORT_SYMBOL(__get_user_4)
 84
 
 85ENTRY(__get_user_8)
 86#ifdef CONFIG_X86_64
 87	add $7,%_ASM_AX
 88	jc bad_get_user
 89	mov PER_CPU_VAR(current_task), %_ASM_DX
 90	cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
 91	jae bad_get_user
 92	sbb %_ASM_DX, %_ASM_DX		/* array_index_mask_nospec() */
 93	and %_ASM_DX, %_ASM_AX
 94	ASM_STAC
 954:	movq -7(%_ASM_AX),%rdx
 96	xor %eax,%eax
 97	ASM_CLAC
 98	ret
 99#else
100	add $7,%_ASM_AX
101	jc bad_get_user_8
102	mov PER_CPU_VAR(current_task), %_ASM_DX
103	cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
104	jae bad_get_user_8
105	sbb %_ASM_DX, %_ASM_DX		/* array_index_mask_nospec() */
106	and %_ASM_DX, %_ASM_AX
107	ASM_STAC
1084:	movl -7(%_ASM_AX),%edx
1095:	movl -3(%_ASM_AX),%ecx
110	xor %eax,%eax
111	ASM_CLAC
112	ret
 
 
113#endif
114ENDPROC(__get_user_8)
115EXPORT_SYMBOL(__get_user_8)
116
117
118.Lbad_get_user_clac:
119	ASM_CLAC
120bad_get_user:
 
121	xor %edx,%edx
122	mov $(-EFAULT),%_ASM_AX
123	ret
 
 
124
125#ifdef CONFIG_X86_32
126.Lbad_get_user_8_clac:
127	ASM_CLAC
128bad_get_user_8:
129	xor %edx,%edx
130	xor %ecx,%ecx
131	mov $(-EFAULT),%_ASM_AX
132	ret
133#endif
134
135	_ASM_EXTABLE_UA(1b, .Lbad_get_user_clac)
136	_ASM_EXTABLE_UA(2b, .Lbad_get_user_clac)
137	_ASM_EXTABLE_UA(3b, .Lbad_get_user_clac)
138#ifdef CONFIG_X86_64
139	_ASM_EXTABLE_UA(4b, .Lbad_get_user_clac)
140#else
141	_ASM_EXTABLE_UA(4b, .Lbad_get_user_8_clac)
142	_ASM_EXTABLE_UA(5b, .Lbad_get_user_8_clac)
143#endif