diff options
| author | Andi Kleen <[email protected]> | 2019-05-08 03:02:20 -0700 |
|---|---|---|
| committer | Thomas Gleixner <[email protected]> | 2019-06-22 11:38:52 +0200 |
| commit | 8b71340d702ec5d587443b38a852671c4fb6a723 (patch) | |
| tree | 0066de5ecf613ac0c4608339ad0528b76e806e58 | |
| parent | 1fb12b35e5ffe379d109b22cb3069830d0136d9a (diff) | |
x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions
[ luto: Rename the variables from FS and GS to FSBASE and GSBASE and
make <asm/fsgsbase.h> safe to include on 32-bit kernels. ]
Signed-off-by: Andi Kleen <[email protected]>
Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Chang S. Bae <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Andy Lutomirski <[email protected]>
Reviewed-by: Andi Kleen <[email protected]>
Cc: Ravi Shankar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
| -rw-r--r-- | arch/x86/include/asm/fsgsbase.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/include/asm/fsgsbase.h b/arch/x86/include/asm/fsgsbase.h index bca4c743de77..fdd1177499b4 100644 --- a/arch/x86/include/asm/fsgsbase.h +++ b/arch/x86/include/asm/fsgsbase.h @@ -19,6 +19,36 @@ 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); +/* Must be protected by X86_FEATURE_FSGSBASE check. */ + +static __always_inline unsigned long rdfsbase(void) +{ + unsigned long fsbase; + + asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory"); + + return fsbase; +} + +static __always_inline unsigned long rdgsbase(void) +{ + unsigned long gsbase; + + asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory"); + + return gsbase; +} + +static __always_inline void wrfsbase(unsigned long fsbase) +{ + asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory"); +} + +static __always_inline void wrgsbase(unsigned long gsbase) +{ + asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory"); +} + /* Helper functions for reading/writing FS/GS base */ static inline unsigned long x86_fsbase_read_cpu(void) |