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 118bad_get_user: 119 xor %edx,%edx 120 mov $(-EFAULT),%_ASM_AX 121 ASM_CLAC 122 ret 123END(bad_get_user) 124 125#ifdef CONFIG_X86_32 126bad_get_user_8: 127 xor %edx,%edx 128 xor %ecx,%ecx 129 mov $(-EFAULT),%_ASM_AX 130 ASM_CLAC 131 ret 132END(bad_get_user_8) 133#endif 134 135 _ASM_EXTABLE(1b,bad_get_user) 136 _ASM_EXTABLE(2b,bad_get_user) 137 _ASM_EXTABLE(3b,bad_get_user) 138#ifdef CONFIG_X86_64 139 _ASM_EXTABLE(4b,bad_get_user) 140#else 141 _ASM_EXTABLE(4b,bad_get_user_8) 142 _ASM_EXTABLE(5b,bad_get_user_8) 143#endif 144