diff options
Diffstat (limited to 'arch/x86/include/asm/fsgsbase.h')
| -rw-r--r-- | arch/x86/include/asm/fsgsbase.h | 47 |
1 files changed, 38 insertions, 9 deletions
diff --git a/arch/x86/include/asm/fsgsbase.h b/arch/x86/include/asm/fsgsbase.h index bca4c743de77..d552646411a9 100644 --- a/arch/x86/include/asm/fsgsbase.h +++ b/arch/x86/include/asm/fsgsbase.h @@ -19,36 +19,65 @@ extern unsigned long x86_gsbase_read_task(struct task_struct *task); extern void x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase); extern void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase); -/* Helper functions for reading/writing FS/GS base */ +/* Must be protected by X86_FEATURE_FSGSBASE check. */ -static inline unsigned long x86_fsbase_read_cpu(void) +static __always_inline unsigned long rdfsbase(void) { unsigned long fsbase; - rdmsrl(MSR_FS_BASE, fsbase); + asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory"); return fsbase; } -static inline unsigned long x86_gsbase_read_cpu_inactive(void) +static __always_inline unsigned long rdgsbase(void) { unsigned long gsbase; - rdmsrl(MSR_KERNEL_GS_BASE, gsbase); + asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory"); return gsbase; } -static inline void x86_fsbase_write_cpu(unsigned long fsbase) +static __always_inline void wrfsbase(unsigned long fsbase) { - wrmsrl(MSR_FS_BASE, fsbase); + asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory"); } -static inline void x86_gsbase_write_cpu_inactive(unsigned long gsbase) +static __always_inline void wrgsbase(unsigned long gsbase) { - wrmsrl(MSR_KERNEL_GS_BASE, gsbase); + asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory"); } +#include <asm/cpufeature.h> + +/* Helper functions for reading/writing FS/GS base */ + +static inline unsigned long x86_fsbase_read_cpu(void) +{ + unsigned long fsbase; + + if (static_cpu_has(X86_FEATURE_FSGSBASE)) + fsbase = rdfsbase(); + else + rdmsrl(MSR_FS_BASE, fsbase); + + return fsbase; +} + +static inline void x86_fsbase_write_cpu(unsigned long fsbase) +{ + if (static_cpu_has(X86_FEATURE_FSGSBASE)) + wrfsbase(fsbase); + else + wrmsrl(MSR_FS_BASE, fsbase); +} + +extern unsigned long x86_gsbase_read_cpu_inactive(void); +extern void x86_gsbase_write_cpu_inactive(unsigned long gsbase); +extern unsigned long x86_fsgsbase_read_task(struct task_struct *task, + unsigned short selector); + #endif /* CONFIG_X86_64 */ #endif /* __ASSEMBLY__ */ |