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authorAndy Lutomirski <luto@kernel.org>2015-06-25 18:44:08 +0200
committerIngo Molnar <mingo@kernel.org>2015-07-06 15:23:29 +0200
commit03b9730b769fc4d87e40f6104f4c5b2e43889f19 (patch)
treea3f46bac8fc6ee76933f5f17c2d9f30059957529 /arch/x86/lib/delay.c
parentx86/asm/tsc: Rename native_read_tsc() to rdtsc() (diff)
downloadlinux-03b9730b769fc4d87e40f6104f4c5b2e43889f19.tar.xz
linux-03b9730b769fc4d87e40f6104f4c5b2e43889f19.zip
x86/asm/tsc: Add rdtsc_ordered() and use it in trivial call sites
rdtsc_barrier(); rdtsc() is an unnecessary mouthful and requires more thought than should be necessary. Add an rdtsc_ordered() helper and replace the trivial call sites with it. This should not change generated code. The duplication of the fence asm is temporary. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: 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>
Diffstat (limited to 'arch/x86/lib/delay.c')
-rw-r--r--arch/x86/lib/delay.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index f24bc59ab0a0..4453d52a143d 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -54,11 +54,9 @@ static void delay_tsc(unsigned long __loops)
preempt_disable();
cpu = smp_processor_id();
- rdtsc_barrier();
- bclock = rdtsc();
+ bclock = rdtsc_ordered();
for (;;) {
- rdtsc_barrier();
- now = rdtsc();
+ now = rdtsc_ordered();
if ((now - bclock) >= loops)
break;
@@ -79,8 +77,7 @@ static void delay_tsc(unsigned long __loops)
if (unlikely(cpu != smp_processor_id())) {
loops -= (now - bclock);
cpu = smp_processor_id();
- rdtsc_barrier();
- bclock = rdtsc();
+ bclock = rdtsc_ordered();
}
}
preempt_enable();