Commit-ID:  99770737ca7e3ebc14e66460a69b7032de9421e1
Gitweb:     http://git.kernel.org/tip/99770737ca7e3ebc14e66460a69b7032de9421e1
Author:     Ingo Molnar <mi...@kernel.org>
AuthorDate: Fri, 21 Aug 2015 08:33:53 +0200
Committer:  Ingo Molnar <mi...@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 <l...@kernel.org>
Cc: Borislav Petkov <b...@suse.de>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Huang Rui <ray.hu...@amd.com>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Len Brown <l...@kernel.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Ralf Baechle <r...@linux-mips.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: 
http://lkml.kernel.org/r/dddbf98a2af53312e9aa73a5a2b1622fe5d6f52b.1434501121.git.l...@kernel.org
Signed-off-by: Ingo Molnar <mi...@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);
--
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