xref: /openbmc/linux/arch/x86/lib/retpoline.S (revision f519cd13)
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
11.macro THUNK reg
12	.section .text.__x86.indirect_thunk
13
14SYM_FUNC_START(__x86_indirect_thunk_\reg)
15	CFI_STARTPROC
16	JMP_NOSPEC %\reg
17	CFI_ENDPROC
18SYM_FUNC_END(__x86_indirect_thunk_\reg)
19.endm
20
21/*
22 * Despite being an assembler file we can't just use .irp here
23 * because __KSYM_DEPS__ only uses the C preprocessor and would
24 * only see one instance of "__x86_indirect_thunk_\reg" rather
25 * than one per register with the correct names. So we do it
26 * the simple and nasty way...
27 */
28#define __EXPORT_THUNK(sym) _ASM_NOKPROBE(sym); EXPORT_SYMBOL(sym)
29#define EXPORT_THUNK(reg) __EXPORT_THUNK(__x86_indirect_thunk_ ## reg)
30#define GENERATE_THUNK(reg) THUNK reg ; EXPORT_THUNK(reg)
31
32GENERATE_THUNK(_ASM_AX)
33GENERATE_THUNK(_ASM_BX)
34GENERATE_THUNK(_ASM_CX)
35GENERATE_THUNK(_ASM_DX)
36GENERATE_THUNK(_ASM_SI)
37GENERATE_THUNK(_ASM_DI)
38GENERATE_THUNK(_ASM_BP)
39#ifdef CONFIG_64BIT
40GENERATE_THUNK(r8)
41GENERATE_THUNK(r9)
42GENERATE_THUNK(r10)
43GENERATE_THUNK(r11)
44GENERATE_THUNK(r12)
45GENERATE_THUNK(r13)
46GENERATE_THUNK(r14)
47GENERATE_THUNK(r15)
48#endif
49