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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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-asm.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.macro THUNK reg
14 .section .text.__x86.indirect_thunk
15
16 .align 32
17SYM_FUNC_START(__x86_indirect_thunk_\reg)
18 JMP_NOSPEC \reg
19SYM_FUNC_END(__x86_indirect_thunk_\reg)
20
21SYM_FUNC_START_NOALIGN(__x86_retpoline_\reg)
22 ANNOTATE_INTRA_FUNCTION_CALL
23 call .Ldo_rop_\@
24.Lspec_trap_\@:
25 UNWIND_HINT_EMPTY
26 pause
27 lfence
28 jmp .Lspec_trap_\@
29.Ldo_rop_\@:
30 mov %\reg, (%_ASM_SP)
31 UNWIND_HINT_RET_OFFSET
32 ret
33SYM_FUNC_END(__x86_retpoline_\reg)
34
35.endm
36
37/*
38 * Despite being an assembler file we can't just use .irp here
39 * because __KSYM_DEPS__ only uses the C preprocessor and would
40 * only see one instance of "__x86_indirect_thunk_\reg" rather
41 * than one per register with the correct names. So we do it
42 * the simple and nasty way...
43 *
44 * Worse, you can only have a single EXPORT_SYMBOL per line,
45 * and CPP can't insert newlines, so we have to repeat everything
46 * at least twice.
47 */
48
49#define __EXPORT_THUNK(sym) _ASM_NOKPROBE(sym); EXPORT_SYMBOL(sym)
50#define EXPORT_THUNK(reg) __EXPORT_THUNK(__x86_indirect_thunk_ ## reg)
51#define EXPORT_RETPOLINE(reg) __EXPORT_THUNK(__x86_retpoline_ ## reg)
52
53#undef GEN
54#define GEN(reg) THUNK reg
55#include <asm/GEN-for-each-reg.h>
56
57#undef GEN
58#define GEN(reg) EXPORT_THUNK(reg)
59#include <asm/GEN-for-each-reg.h>
60
61#undef GEN
62#define GEN(reg) EXPORT_RETPOLINE(reg)
63#include <asm/GEN-for-each-reg.h>