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| author | Andy Lutomirski <luto@kernel.org> | 2016-11-16 21:23:27 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-28 17:38:46 +0300 |
| commit | 91d37bc12d0014fe6e77b041429c35ed5c6b4fcc (patch) | |
| tree | ddfe4930b767d54ccfe71144f44831abe058d397 /lib/strnlen_user.c | |
| parent | 76e5c6fd6d163f1aa63969cc982e79be1fee87a7 (diff) | |
| download | linux-91d37bc12d0014fe6e77b041429c35ed5c6b4fcc.tar.xz | |
x86/vdso: Use RDPID in preference to LSL when available
commit a582c540ac1b10f0a7d37415e04c4af42409fd08 upstream.
RDPID is a new instruction that reads MSR_TSC_AUX quickly. This
should be considerably faster than reading the GDT. Add a
cpufeature for it and use it from __vdso_getcpu() when available.
Tested-by: Megha Dey <megha.dey@intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/4f6c3a22012d10f1c65b9ca15800e01b42c7d39d.1479320367.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/strnlen_user.c')
0 files changed, 0 insertions, 0 deletions