| /* 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 |
| |
| #ifdef CONFIG_X86_5LEVEL |
| #define LOAD_TASK_SIZE_MINUS_N(n) \ |
| ALTERNATIVE __stringify(mov $((1 << 47) - 4096 - (n)),%rdx), \ |
| __stringify(mov $((1 << 56) - 4096 - (n)),%rdx), X86_FEATURE_LA57 |
| #else |
| #define LOAD_TASK_SIZE_MINUS_N(n) \ |
| mov $(TASK_SIZE_MAX - (n)),%_ASM_DX |
| #endif |
| |
| .text |
| SYM_FUNC_START(__get_user_1) |
| LOAD_TASK_SIZE_MINUS_N(0) |
| cmp %_ASM_DX,%_ASM_AX |
| jae bad_get_user |
| sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ |
| and %_ASM_DX, %_ASM_AX |
| 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) |
| LOAD_TASK_SIZE_MINUS_N(1) |
| cmp %_ASM_DX,%_ASM_AX |
| jae bad_get_user |
| sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ |
| and %_ASM_DX, %_ASM_AX |
| 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) |
| LOAD_TASK_SIZE_MINUS_N(3) |
| cmp %_ASM_DX,%_ASM_AX |
| jae bad_get_user |
| sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ |
| and %_ASM_DX, %_ASM_AX |
| 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) |
| #ifdef CONFIG_X86_64 |
| LOAD_TASK_SIZE_MINUS_N(7) |
| cmp %_ASM_DX,%_ASM_AX |
| jae bad_get_user |
| sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ |
| and %_ASM_DX, %_ASM_AX |
| ASM_STAC |
| 4: movq (%_ASM_AX),%rdx |
| xor %eax,%eax |
| ASM_CLAC |
| ret |
| #else |
| LOAD_TASK_SIZE_MINUS_N(7) |
| cmp %_ASM_DX,%_ASM_AX |
| jae bad_get_user_8 |
| sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */ |
| and %_ASM_DX, %_ASM_AX |
| ASM_STAC |
| 4: movl (%_ASM_AX),%edx |
| 5: movl 4(%_ASM_AX),%ecx |
| xor %eax,%eax |
| ASM_CLAC |
| ret |
| #endif |
| 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(.Lbad_get_user_clac) |
| ASM_CLAC |
| bad_get_user: |
| xor %edx,%edx |
| mov $(-EFAULT),%_ASM_AX |
| ret |
| SYM_CODE_END(.Lbad_get_user_clac) |
| |
| #ifdef CONFIG_X86_32 |
| SYM_CODE_START_LOCAL(.Lbad_get_user_8_clac) |
| ASM_CLAC |
| bad_get_user_8: |
| xor %edx,%edx |
| xor %ecx,%ecx |
| mov $(-EFAULT),%_ASM_AX |
| ret |
| SYM_CODE_END(.Lbad_get_user_8_clac) |
| #endif |
| |
| /* get_user */ |
| _ASM_EXTABLE_UA(1b, .Lbad_get_user_clac) |
| _ASM_EXTABLE_UA(2b, .Lbad_get_user_clac) |
| _ASM_EXTABLE_UA(3b, .Lbad_get_user_clac) |
| #ifdef CONFIG_X86_64 |
| _ASM_EXTABLE_UA(4b, .Lbad_get_user_clac) |
| #else |
| _ASM_EXTABLE_UA(4b, .Lbad_get_user_8_clac) |
| _ASM_EXTABLE_UA(5b, .Lbad_get_user_8_clac) |
| #endif |
| |
| /* __get_user */ |
| _ASM_EXTABLE_UA(6b, .Lbad_get_user_clac) |
| _ASM_EXTABLE_UA(7b, .Lbad_get_user_clac) |
| _ASM_EXTABLE_UA(8b, .Lbad_get_user_clac) |
| #ifdef CONFIG_X86_64 |
| _ASM_EXTABLE_UA(9b, .Lbad_get_user_clac) |
| #else |
| _ASM_EXTABLE_UA(9b, .Lbad_get_user_8_clac) |
| _ASM_EXTABLE_UA(10b, .Lbad_get_user_8_clac) |
| #endif |
