retpoline.S (1792B)
1/* SPDX-License-Identifier: GPL-2.0 */ 2 3#include <linux/stringify.h> 4#include <linux/linkage.h> 5#include <asm/dwarf2.h> 6#include <asm/cpufeatures.h> 7#include <asm/alternative.h> 8#include <asm/export.h> 9#include <asm/nospec-branch.h> 10#include <asm/unwind_hints.h> 11#include <asm/frame.h> 12 13 .section .text.__x86.indirect_thunk 14 15.macro RETPOLINE reg 16 ANNOTATE_INTRA_FUNCTION_CALL 17 call .Ldo_rop_\@ 18.Lspec_trap_\@: 19 UNWIND_HINT_EMPTY 20 pause 21 lfence 22 jmp .Lspec_trap_\@ 23.Ldo_rop_\@: 24 mov %\reg, (%_ASM_SP) 25 UNWIND_HINT_FUNC 26 RET 27.endm 28 29.macro THUNK reg 30 31 .align RETPOLINE_THUNK_SIZE 32SYM_INNER_LABEL(__x86_indirect_thunk_\reg, SYM_L_GLOBAL) 33 UNWIND_HINT_EMPTY 34 ANNOTATE_NOENDBR 35 36 ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *%\reg), \ 37 __stringify(RETPOLINE \reg), X86_FEATURE_RETPOLINE, \ 38 __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *%\reg; int3), X86_FEATURE_RETPOLINE_LFENCE 39 40.endm 41 42/* 43 * Despite being an assembler file we can't just use .irp here 44 * because __KSYM_DEPS__ only uses the C preprocessor and would 45 * only see one instance of "__x86_indirect_thunk_\reg" rather 46 * than one per register with the correct names. So we do it 47 * the simple and nasty way... 48 * 49 * Worse, you can only have a single EXPORT_SYMBOL per line, 50 * and CPP can't insert newlines, so we have to repeat everything 51 * at least twice. 52 */ 53 54#define __EXPORT_THUNK(sym) _ASM_NOKPROBE(sym); EXPORT_SYMBOL(sym) 55#define EXPORT_THUNK(reg) __EXPORT_THUNK(__x86_indirect_thunk_ ## reg) 56 57 .align RETPOLINE_THUNK_SIZE 58SYM_CODE_START(__x86_indirect_thunk_array) 59 60#define GEN(reg) THUNK reg 61#include <asm/GEN-for-each-reg.h> 62#undef GEN 63 64 .align RETPOLINE_THUNK_SIZE 65SYM_CODE_END(__x86_indirect_thunk_array) 66 67#define GEN(reg) EXPORT_THUNK(reg) 68#include <asm/GEN-for-each-reg.h> 69#undef GEN