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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_FSGSBASE_H
3#define _ASM_FSGSBASE_H
4
5#ifndef __ASSEMBLY__
6
7#ifdef CONFIG_X86_64
8
9#include <asm/msr-index.h>
10
11/*
12 * Read/write a task's FSBASE or GSBASE. This returns the value that
13 * the FS/GS base would have (if the task were to be resumed). These
14 * work on the current task or on a non-running (typically stopped
15 * ptrace child) task.
16 */
17extern unsigned long x86_fsbase_read_task(struct task_struct *task);
18extern unsigned long x86_gsbase_read_task(struct task_struct *task);
19extern void x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase);
20extern void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase);
21
22/* Helper functions for reading/writing FS/GS base */
23
24static inline unsigned long x86_fsbase_read_cpu(void)
25{
26 unsigned long fsbase;
27
28 rdmsrl(MSR_FS_BASE, fsbase);
29
30 return fsbase;
31}
32
33static inline unsigned long x86_gsbase_read_cpu_inactive(void)
34{
35 unsigned long gsbase;
36
37 rdmsrl(MSR_KERNEL_GS_BASE, gsbase);
38
39 return gsbase;
40}
41
42static inline void x86_fsbase_write_cpu(unsigned long fsbase)
43{
44 wrmsrl(MSR_FS_BASE, fsbase);
45}
46
47static inline void x86_gsbase_write_cpu_inactive(unsigned long gsbase)
48{
49 wrmsrl(MSR_KERNEL_GS_BASE, gsbase);
50}
51
52#endif /* CONFIG_X86_64 */
53
54#endif /* __ASSEMBLY__ */
55
56#endif /* _ASM_FSGSBASE_H */