| 1 |
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| 2 | |
| 3 | * Clang Control Flow Integrity (CFI) type definitions.
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| 4 |
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| 5 | #ifndef _LINUX_CFI_TYPES_H
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| 6 | #define _LINUX_CFI_TYPES_H
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| 7 |
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| 8 | #ifdef __ASSEMBLY__
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| 9 | #include <linux/linkage.h>
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| 10 |
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| 11 | #ifdef CONFIG_CFI
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| 12 | |
| 13 | * Use the __kcfi_typeid_<function> type identifier symbol to
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| 14 | * annotate indirectly called assembly functions. The compiler emits
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| 15 | * these symbols for all address-taken function declarations in C
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| 16 | * code.
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| 17 |
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| 18 | #ifndef __CFI_TYPE
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| 19 | #define __CFI_TYPE(name) \
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| 20 | .4byte __kcfi_typeid_##name
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| 21 | #endif
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| 22 |
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| 23 | #define SYM_TYPED_ENTRY(name, linkage, align...) \
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| 24 | linkage(name) ASM_NL \
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| 25 | align ASM_NL \
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| 26 | __CFI_TYPE(name) ASM_NL \
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| 27 | name:
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| 28 |
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| 29 | #define SYM_TYPED_START(name, linkage, align...) \
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| 30 | SYM_TYPED_ENTRY(name, linkage, align)
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| 31 |
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| 32 | #else
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| 33 |
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| 34 | #define SYM_TYPED_START(name, linkage, align...) \
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| 35 | SYM_START(name, linkage, align)
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| 36 |
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| 37 | #endif
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| 38 |
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| 39 | #ifndef SYM_TYPED_FUNC_START
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| 40 | #define SYM_TYPED_FUNC_START(name) \
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| 41 | SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN)
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| 42 | #endif
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| 43 |
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| 44 | #else
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| 45 |
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| 46 | #ifdef CONFIG_CFI
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| 47 | #define DEFINE_CFI_TYPE(name, func) \
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| 48 | |
| 49 | * Force a reference to the function so the compiler generates \
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| 50 | * __kcfi_typeid_<func>. \
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| 51 | \
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| 52 | __ADDRESSABLE(func); \
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| 53 | \
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| 54 | extern u32 name; \
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| 55 | asm ( \
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| 56 | " .pushsection .data..ro_after_init,\"aw\",\%progbits \n" \
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| 57 | " .type " #name ",\%object \n" \
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| 58 | " .globl " #name " \n" \
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| 59 | " .p2align 2, 0x0 \n" \
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| 60 | #name ": \n" \
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| 61 | " .4byte __kcfi_typeid_" #func " \n" \
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| 62 | " .size " #name ", 4 \n" \
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| 63 | " .popsection \n" \
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| 64 | );
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| 65 | #endif
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| 66 |
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| 67 | #endif
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| 68 | #endif
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