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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | /* SPDX-License-Identifier: GPL-2.0 */ /* * __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. * * Outputs: %[r|e]ax is error code (0 or -EFAULT) * %[r|e]dx contains zero-extended value * %ecx contains the high half for 32-bit __get_user_8 * * * These functions should not modify any other registers, * as they get called from within inline assembly. */ #include <linux/linkage.h> #include <asm/page_types.h> #include <asm/errno.h> #include <asm/asm-offsets.h> #include <asm/thread_info.h> #include <asm/asm.h> #include <asm/smap.h> #include <asm/export.h> #define ASM_BARRIER_NOSPEC ALTERNATIVE "", "lfence", X86_FEATURE_LFENCE_RDTSC .macro check_range size:req .if IS_ENABLED(CONFIG_X86_64) mov %rax, %rdx sar $63, %rdx or %rdx, %rax .else cmp $TASK_SIZE_MAX-\size+1, %eax .if \size != 8 jae .Lbad_get_user .else jae .Lbad_get_user_8 .endif sbb %edx, %edx /* array_index_mask_nospec() */ and %edx, %eax .endif .endm .text SYM_FUNC_START(__get_user_1) check_range size=1 ASM_STAC 1: movzbl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_1) EXPORT_SYMBOL(__get_user_1) SYM_FUNC_START(__get_user_2) check_range size=2 ASM_STAC 2: movzwl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_2) EXPORT_SYMBOL(__get_user_2) SYM_FUNC_START(__get_user_4) check_range size=4 ASM_STAC 3: movl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_4) EXPORT_SYMBOL(__get_user_4) SYM_FUNC_START(__get_user_8) check_range size=8 ASM_STAC #ifdef CONFIG_X86_64 4: movq (%_ASM_AX),%rdx #else 4: movl (%_ASM_AX),%edx 5: movl 4(%_ASM_AX),%ecx #endif xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_8) EXPORT_SYMBOL(__get_user_8) /* .. and the same for __get_user, just without the range checks */ SYM_FUNC_START(__get_user_nocheck_1) ASM_STAC ASM_BARRIER_NOSPEC 6: movzbl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_nocheck_1) EXPORT_SYMBOL(__get_user_nocheck_1) SYM_FUNC_START(__get_user_nocheck_2) ASM_STAC ASM_BARRIER_NOSPEC 7: movzwl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_nocheck_2) EXPORT_SYMBOL(__get_user_nocheck_2) SYM_FUNC_START(__get_user_nocheck_4) ASM_STAC ASM_BARRIER_NOSPEC 8: movl (%_ASM_AX),%edx xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_nocheck_4) EXPORT_SYMBOL(__get_user_nocheck_4) SYM_FUNC_START(__get_user_nocheck_8) ASM_STAC ASM_BARRIER_NOSPEC #ifdef CONFIG_X86_64 9: movq (%_ASM_AX),%rdx #else 9: movl (%_ASM_AX),%edx 10: movl 4(%_ASM_AX),%ecx #endif xor %eax,%eax ASM_CLAC RET SYM_FUNC_END(__get_user_nocheck_8) EXPORT_SYMBOL(__get_user_nocheck_8) SYM_CODE_START_LOCAL(__get_user_handle_exception) ASM_CLAC .Lbad_get_user: xor %edx,%edx mov $(-EFAULT),%_ASM_AX RET SYM_CODE_END(__get_user_handle_exception) #ifdef CONFIG_X86_32 SYM_CODE_START_LOCAL(__get_user_8_handle_exception) ASM_CLAC .Lbad_get_user_8: xor %edx,%edx xor %ecx,%ecx mov $(-EFAULT),%_ASM_AX RET SYM_CODE_END(__get_user_8_handle_exception) #endif /* get_user */ _ASM_EXTABLE_UA(1b, __get_user_handle_exception) _ASM_EXTABLE_UA(2b, __get_user_handle_exception) _ASM_EXTABLE_UA(3b, __get_user_handle_exception) #ifdef CONFIG_X86_64 _ASM_EXTABLE_UA(4b, __get_user_handle_exception) #else _ASM_EXTABLE_UA(4b, __get_user_8_handle_exception) _ASM_EXTABLE_UA(5b, __get_user_8_handle_exception) #endif /* __get_user */ _ASM_EXTABLE_UA(6b, __get_user_handle_exception) _ASM_EXTABLE_UA(7b, __get_user_handle_exception) _ASM_EXTABLE_UA(8b, __get_user_handle_exception) #ifdef CONFIG_X86_64 _ASM_EXTABLE_UA(9b, __get_user_handle_exception) #else _ASM_EXTABLE_UA(9b, __get_user_8_handle_exception) _ASM_EXTABLE_UA(10b, __get_user_8_handle_exception) #endif |