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/export.h>
 30#include <linux/linkage.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#include <asm/smap.h>
 37
 38#define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lfence", X86_FEATURE_LFENCE_RDTSC
 39
 40.macro check_range size:req
 41.if IS_ENABLED(CONFIG_X86_64)
 42	mov %rax, %rdx
 43	sar $63, %rdx
 44	or %rdx, %rax
 45.else
 46	cmp $TASK_SIZE_MAX-\size+1, %eax
 47	jae .Lbad_get_user
 48	sbb %edx, %edx		/* array_index_mask_nospec() */
 49	and %edx, %eax
 50.endif
 51.endm
 52
 53	.text
 54SYM_FUNC_START(__get_user_1)
 55	check_range size=1
 56	ASM_STAC
 571:	movzbl (%_ASM_AX),%edx
 58	xor %eax,%eax
 59	ASM_CLAC
 60	RET
 61SYM_FUNC_END(__get_user_1)
 62EXPORT_SYMBOL(__get_user_1)
 63
 64SYM_FUNC_START(__get_user_2)
 65	check_range size=2
 66	ASM_STAC
 672:	movzwl (%_ASM_AX),%edx
 68	xor %eax,%eax
 69	ASM_CLAC
 70	RET
 71SYM_FUNC_END(__get_user_2)
 72EXPORT_SYMBOL(__get_user_2)
 73
 74SYM_FUNC_START(__get_user_4)
 75	check_range size=4
 76	ASM_STAC
 773:	movl (%_ASM_AX),%edx
 78	xor %eax,%eax
 79	ASM_CLAC
 80	RET
 81SYM_FUNC_END(__get_user_4)
 82EXPORT_SYMBOL(__get_user_4)
 83
 84SYM_FUNC_START(__get_user_8)
 85	check_range size=8
 86	ASM_STAC
 87#ifdef CONFIG_X86_64
 884:	movq (%_ASM_AX),%rdx
 89#else
 904:	movl (%_ASM_AX),%edx
 915:	movl 4(%_ASM_AX),%ecx
 92#endif
 93	xor %eax,%eax
 94	ASM_CLAC
 95	RET
 96SYM_FUNC_END(__get_user_8)
 97EXPORT_SYMBOL(__get_user_8)
 98
 99/* .. and the same for __get_user, just without the range checks */
100SYM_FUNC_START(__get_user_nocheck_1)
101	ASM_STAC
102	ASM_BARRIER_NOSPEC
1036:	movzbl (%_ASM_AX),%edx
104	xor %eax,%eax
105	ASM_CLAC
106	RET
107SYM_FUNC_END(__get_user_nocheck_1)
108EXPORT_SYMBOL(__get_user_nocheck_1)
109
110SYM_FUNC_START(__get_user_nocheck_2)
111	ASM_STAC
112	ASM_BARRIER_NOSPEC
1137:	movzwl (%_ASM_AX),%edx
114	xor %eax,%eax
115	ASM_CLAC
116	RET
117SYM_FUNC_END(__get_user_nocheck_2)
118EXPORT_SYMBOL(__get_user_nocheck_2)
119
120SYM_FUNC_START(__get_user_nocheck_4)
121	ASM_STAC
122	ASM_BARRIER_NOSPEC
1238:	movl (%_ASM_AX),%edx
124	xor %eax,%eax
125	ASM_CLAC
126	RET
127SYM_FUNC_END(__get_user_nocheck_4)
128EXPORT_SYMBOL(__get_user_nocheck_4)
129
130SYM_FUNC_START(__get_user_nocheck_8)
131	ASM_STAC
132	ASM_BARRIER_NOSPEC
133#ifdef CONFIG_X86_64
1349:	movq (%_ASM_AX),%rdx
135#else
1369:	movl (%_ASM_AX),%edx
13710:	movl 4(%_ASM_AX),%ecx
 
 
 
 
 
 
 
 
138#endif
139	xor %eax,%eax
140	ASM_CLAC
141	RET
142SYM_FUNC_END(__get_user_nocheck_8)
143EXPORT_SYMBOL(__get_user_nocheck_8)
144
145
146SYM_CODE_START_LOCAL(__get_user_handle_exception)
147	ASM_CLAC
148.Lbad_get_user:
149	xor %edx,%edx
150	mov $(-EFAULT),%_ASM_AX
151	RET
152SYM_CODE_END(__get_user_handle_exception)
153
154#ifdef CONFIG_X86_32
155SYM_CODE_START_LOCAL(__get_user_8_handle_exception)
156	ASM_CLAC
157bad_get_user_8:
158	xor %edx,%edx
159	xor %ecx,%ecx
160	mov $(-EFAULT),%_ASM_AX
161	RET
162SYM_CODE_END(__get_user_8_handle_exception)
163#endif
164
165/* get_user */
166	_ASM_EXTABLE_UA(1b, __get_user_handle_exception)
167	_ASM_EXTABLE_UA(2b, __get_user_handle_exception)
168	_ASM_EXTABLE_UA(3b, __get_user_handle_exception)
169#ifdef CONFIG_X86_64
170	_ASM_EXTABLE_UA(4b, __get_user_handle_exception)
171#else
172	_ASM_EXTABLE_UA(4b, __get_user_8_handle_exception)
173	_ASM_EXTABLE_UA(5b, __get_user_8_handle_exception)
174#endif
175
176/* __get_user */
177	_ASM_EXTABLE_UA(6b, __get_user_handle_exception)
178	_ASM_EXTABLE_UA(7b, __get_user_handle_exception)
179	_ASM_EXTABLE_UA(8b, __get_user_handle_exception)
180#ifdef CONFIG_X86_64
181	_ASM_EXTABLE_UA(9b, __get_user_handle_exception)
182#else
183	_ASM_EXTABLE_UA(9b, __get_user_8_handle_exception)
184	_ASM_EXTABLE_UA(10b, __get_user_8_handle_exception)
185#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 *		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	_ASM_EXTABLE(1b,bad_get_user)
 99	_ASM_EXTABLE(2b,bad_get_user)
100	_ASM_EXTABLE(3b,bad_get_user)
 
 
 
 
 
 
 
 
 
 
 
 
101#ifdef CONFIG_X86_64
102	_ASM_EXTABLE(4b,bad_get_user)
 
 
 
103#endif