Commit-ID: 8b71340d702ec5d587443b38a852671c4fb6a723
Gitweb: https://git.kernel.org/tip/8b71340d702ec5d587443b38a852671c4fb6a723
Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 8 May 2019 03:02:20 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sat, 22 Jun 2019 11:38:52 +0200
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 <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Link: https://lkml.kernel.org/r/1557309753-24073-6-git-send-email-chang.seok.bae@xxxxxxxxx
---
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 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)
|