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x86: Avoid check hlt for newer cpus

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Check hlt instruction was targeted for some older CPUs. It is an expensive
operation in that it takes 4 ticks to break out the check.  We can avoid
such check completely for newer x86 cpus (family >= 5).

[ hpa: corrected family > 5 to family >= 5 ]

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
LKML-Reference: <1273269585-14346-1-git-send-email-jacob.jun.pan@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Jacob Pan 2010-05-07 14:59:45 -07:00 committed by H. Peter Anvin
parent 722154e4ca
commit 2b107d9363
1 changed files with 1 additions and 1 deletions
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arch/x86/kernel/cpu/bugs.c
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@ -86,7 +86,7 @@ static void __init check_fpu(void)
static void __init check_hlt(void)
{
if (paravirt_enabled())
if (boot_cpu_data.x86 >= 5 || paravirt_enabled())
return;
printk(KERN_INFO "Checking 'hlt' instruction... ");