Commit-ID: f4550b52e495e1b634d1f2c1004bcea5dc3321ea Gitweb: https://git.kernel.org/tip/f4550b52e495e1b634d1f2c1004bcea5dc3321ea Author: Chang S. Bae <[email protected]> AuthorDate: Tue, 18 Sep 2018 16:08:56 -0700 Committer: Ingo Molnar <[email protected]> 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 <[email protected]> Reviewed-by: Andi Kleen <[email protected]> Reviewed-by: Andy Lutomirski <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Markus T Metzger <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Ravi Shankar <[email protected]> Cc: Rik van Riel <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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);
