The following commit has been merged into the x86/fsgsbase branch of tip: Commit-ID: b15378ca50810c1350086cafad3fe19979262a83 Gitweb: https://git.kernel.org/tip/b15378ca50810c1350086cafad3fe19979262a83 Author: Andi Kleen <[email protected]> AuthorDate: Thu, 28 May 2020 16:13:49 -04:00 Committer: Thomas Gleixner <[email protected]> CommitterDate: Thu, 18 Jun 2020 15:47:00 +02:00
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]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Andy Lutomirski <[email protected]> Reviewed-by: Andi Kleen <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] --- arch/x86/include/asm/fsgsbase.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/arch/x86/include/asm/fsgsbase.h b/arch/x86/include/asm/fsgsbase.h index bca4c74..fdd1177 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)
