Commit-ID: f4550b52e495e1b634d1f2c1004bcea5dc3321ea
Gitweb: https://git.kernel.org/tip/f4550b52e495e1b634d1f2c1004bcea5dc3321ea
Author: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
AuthorDate: Tue, 18 Sep 2018 16:08:56 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 8 Oct 2018 10:41:09 +0200
x86/fsgsbase/64: Factor out FS/GS segment loading from __switch_to()
Instead of open coding the calls to load_seg_legacy(), introduce
x86_fsgsbase_load() to load FS/GS segments.
This makes it more explicit that this is part of FSGSBASE functionality,
and the new helper can be updated when FSGSBASE instructions are enabled.
[ mingo: Wrote new changelog. ]
Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Markus T Metzger <markus.t.metzger@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ravi Shankar <ravi.v.shankar@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1537312139-5580-6-git-send-email-chang.seok.bae@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/process_64.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e5fb0c3dee4d..d6674a425714 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -287,6 +287,15 @@ static __always_inline void load_seg_legacy(unsigned short prev_index,
}
}
+static __always_inline void x86_fsgsbase_load(struct thread_struct *prev,
+ struct thread_struct *next)
+{
+ load_seg_legacy(prev->fsindex, prev->fsbase,
+ next->fsindex, next->fsbase, FS);
+ load_seg_legacy(prev->gsindex, prev->gsbase,
+ next->gsindex, next->gsbase, GS);
+}
+
static unsigned long x86_fsgsbase_read_task(struct task_struct *task,
unsigned short selector)
{
@@ -597,10 +606,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
if (unlikely(next->ds | prev->ds))
loadsegment(ds, next->ds);
- load_seg_legacy(prev->fsindex, prev->fsbase,
- next->fsindex, next->fsbase, FS);
- load_seg_legacy(prev->gsindex, prev->gsbase,
- next->gsindex, next->gsbase, GS);
+ x86_fsgsbase_load(prev, next);
switch_fpu_finish(next_fpu, cpu);
|