cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

fsgsbase.h (2072B)

      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/* Must be protected by X86_FEATURE_FSGSBASE check. */
     23
     24static __always_inline unsigned long rdfsbase(void)
     25{
     26	unsigned long fsbase;
     27
     28	asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory");
     29
     30	return fsbase;
     31}
     32
     33static __always_inline unsigned long rdgsbase(void)
     34{
     35	unsigned long gsbase;
     36
     37	asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory");
     38
     39	return gsbase;
     40}
     41
     42static __always_inline void wrfsbase(unsigned long fsbase)
     43{
     44	asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory");
     45}
     46
     47static __always_inline void wrgsbase(unsigned long gsbase)
     48{
     49	asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory");
     50}
     51
     52#include <asm/cpufeature.h>
     53
     54/* Helper functions for reading/writing FS/GS base */
     55
     56static inline unsigned long x86_fsbase_read_cpu(void)
     57{
     58	unsigned long fsbase;
     59
     60	if (boot_cpu_has(X86_FEATURE_FSGSBASE))
     61		fsbase = rdfsbase();
     62	else
     63		rdmsrl(MSR_FS_BASE, fsbase);
     64
     65	return fsbase;
     66}
     67
     68static inline void x86_fsbase_write_cpu(unsigned long fsbase)
     69{
     70	if (boot_cpu_has(X86_FEATURE_FSGSBASE))
     71		wrfsbase(fsbase);
     72	else
     73		wrmsrl(MSR_FS_BASE, fsbase);
     74}
     75
     76extern unsigned long x86_gsbase_read_cpu_inactive(void);
     77extern void x86_gsbase_write_cpu_inactive(unsigned long gsbase);
     78extern unsigned long x86_fsgsbase_read_task(struct task_struct *task,
     79					    unsigned short selector);
     80
     81#endif /* CONFIG_X86_64 */
     82
     83#endif /* __ASSEMBLY__ */
     84
     85#endif /* _ASM_FSGSBASE_H */