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authorAndy Lutomirski <luto@kernel.org>2015-06-25 18:44:00 +0200
committerIngo Molnar <mingo@kernel.org>2015-07-06 15:23:27 +0200
commit9cfa1a0279e22063a727fd204a75cf3672860d83 (patch)
tree7a8c221d47275dfaff9f82430a9106afb260c686 /arch/x86/lib/delay.c
parentec69de52c648b1d9416a810943e68dbe9fe519f4 (diff)
x86/asm/tsc: Use the full 64-bit TSC in delay_tsc()
As a very minor optimization, delay_tsc() was only using the low 32 bits of the TSC. It's a delay function, so just use the whole thing. 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/bd1a277c71321b67c4794970cb5ace05efe21ab6.1434501121.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.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index 9a52ad0c0758..35115f3786a9 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -49,16 +49,16 @@ static void delay_loop(unsigned long loops)
/* TSC based delay: */
static void delay_tsc(unsigned long __loops)
{
- u32 bclock, now, loops = __loops;
+ u64 bclock, now, loops = __loops;
int cpu;
preempt_disable();
cpu = smp_processor_id();
rdtsc_barrier();
- rdtscl(bclock);
+ bclock = native_read_tsc();
for (;;) {
rdtsc_barrier();
- rdtscl(now);
+ now = native_read_tsc();
if ((now - bclock) >= loops)
break;
@@ -80,7 +80,7 @@ static void delay_tsc(unsigned long __loops)
loops -= (now - bclock);
cpu = smp_processor_id();
rdtsc_barrier();
- rdtscl(bclock);
+ bclock = native_read_tsc();
}
}
preempt_enable();