Messages in this thread Patch in this message | | | Date | Fri, 21 Aug 2015 00:45:30 -0700 | From | tip-bot for Ingo Molnar <> | Subject | [tip:x86/asm] x86/asm/tsc: Add rdtscll() merge helper |
| |
Commit-ID: 99770737ca7e3ebc14e66460a69b7032de9421e1 Gitweb: http://git.kernel.org/tip/99770737ca7e3ebc14e66460a69b7032de9421e1 Author: Ingo Molnar <mingo@kernel.org> AuthorDate: Fri, 21 Aug 2015 08:33:53 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Fri, 21 Aug 2015 08:35:42 +0200
x86/asm/tsc: Add rdtscll() merge helper
Some in-flight code makes use of the old rdtscll() (now removed), provide a wrapper for a kernel cycle to smooth the transition to rdtsc().
( We use the safest variant, rdtsc_ordered(), which has barriers - this adds another incentive to remove the wrapper in the future. )
Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> 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: Huang Rui <ray.huang@amd.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kvm ML <kvm@vger.kernel.org> Link: http://lkml.kernel.org/r/dddbf98a2af53312e9aa73a5a2b1622fe5d6f52b.1434501121.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/include/asm/msr.h | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 131eec2..54e9f08 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -152,6 +152,9 @@ static __always_inline unsigned long long rdtsc_ordered(void) return rdtsc(); } +/* Deprecated, keep it for a cycle for easier merging: */ +#define rdtscll(now) do { (now) = rdtsc_ordered(); } while (0) + static inline unsigned long long native_read_pmc(int counter) { DECLARE_ARGS(val, low, high);
| |