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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>
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1 changed files with 4 additions and 4 deletions
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@ -49,16 +49,16 @@ static void delay_loop(unsigned long loops)
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/* TSC based delay: */
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static void delay_tsc(unsigned long __loops)
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{
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u32 bclock, now, loops = __loops;
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u64 bclock, now, loops = __loops;
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int cpu;
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preempt_disable();
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cpu = smp_processor_id();
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rdtsc_barrier();
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rdtscl(bclock);
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bclock = native_read_tsc();
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for (;;) {
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rdtsc_barrier();
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rdtscl(now);
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now = native_read_tsc();
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if ((now - bclock) >= loops)
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break;
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@ -80,7 +80,7 @@ static void delay_tsc(unsigned long __loops)
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loops -= (now - bclock);
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cpu = smp_processor_id();
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rdtsc_barrier();
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rdtscl(bclock);
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bclock = native_read_tsc();
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}
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}
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preempt_enable();
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