projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b1378a56 CB |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | #ifndef _ASM_FSGSBASE_H | |
| ec3a9418 | 3 | #define _ASM_FSGSBASE_H |
| b1378a56 CB |
4 | |
| 5 | #ifndef __ASSEMBLY__ | |
| 6 | ||
| 7 | #ifdef CONFIG_X86_64 | |
| 8 | ||
| 154fcf3a | 9 | #include <asm/msr.h> |
| b1378a56 | 10 | |
| b1378a56 | 11 | /* |
| ec3a9418 | 12 | * Read/write a task's FSBASE or GSBASE. This returns the value that |
| b1378a56 | 13 | * the FS/GS base would have (if the task were to be resumed). These |
| ec3a9418 IM |
14 | * work on the current task or on a non-running (typically stopped |
| 15 | * ptrace child) task. | |
| b1378a56 | 16 | */ |
| ec3a9418 IM |
17 | extern unsigned long x86_fsbase_read_task(struct task_struct *task); |
| 18 | extern unsigned long x86_gsbase_read_task(struct task_struct *task); | |
| 87ab4689 CB |
19 | extern void x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase); |
| 20 | extern void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase); | |
| b1378a56 | 21 | |
| b15378ca AK |
22 | /* Must be protected by X86_FEATURE_FSGSBASE check. */ |
| 23 | ||
| 24 | static __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 | ||
| 33 | static __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 | ||
| 42 | static __always_inline void wrfsbase(unsigned long fsbase) | |
| 43 | { | |
| 44 | asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory"); | |
| 45 | } | |
| 46 | ||
| 47 | static __always_inline void wrgsbase(unsigned long gsbase) | |
| 48 | { | |
| 49 | asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory"); | |
| 50 | } | |
| 51 | ||
| 58edfd2e CB |
52 | #include <asm/cpufeature.h> |
| 53 | ||
| b1378a56 CB |
54 | /* Helper functions for reading/writing FS/GS base */ |
| 55 | ||
| 56 | static inline unsigned long x86_fsbase_read_cpu(void) | |
| 57 | { | |
| 58 | unsigned long fsbase; | |
| 59 | ||
| 5f1dd4dd | 60 | if (boot_cpu_has(X86_FEATURE_FSGSBASE)) |
| 58edfd2e CB |
61 | fsbase = rdfsbase(); |
| 62 | else | |
| 63 | rdmsrl(MSR_FS_BASE, fsbase); | |
| ec3a9418 | 64 | |
| b1378a56 CB |
65 | return fsbase; |
| 66 | } | |
| 67 | ||
| 87ab4689 CB |
68 | static inline void x86_fsbase_write_cpu(unsigned long fsbase) |
| 69 | { | |
| 5f1dd4dd | 70 | if (boot_cpu_has(X86_FEATURE_FSGSBASE)) |
| 58edfd2e CB |
71 | wrfsbase(fsbase); |
| 72 | else | |
| 73 | wrmsrl(MSR_FS_BASE, fsbase); | |
| 87ab4689 CB |
74 | } |
| 75 | ||
| 58edfd2e CB |
76 | extern unsigned long x86_gsbase_read_cpu_inactive(void); |
| 77 | extern void x86_gsbase_write_cpu_inactive(unsigned long gsbase); | |
| 40c45904 AL |
78 | extern unsigned long x86_fsgsbase_read_task(struct task_struct *task, |
| 79 | unsigned short selector); | |
| b1378a56 CB |
80 | |
| 81 | #endif /* CONFIG_X86_64 */ | |
| 82 | ||
| 83 | #endif /* __ASSEMBLY__ */ | |
| 84 | ||
| 85 | #endif /* _ASM_FSGSBASE_H */ |