Commit-ID: 2b107d93635616db0c3f893c8cc2e6d5cd8d77b2
Gitweb: http://git.kernel.org/tip/2b107d93635616db0c3f893c8cc2e6d5cd8d77b2
Author: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 7 May 2010 14:59:45 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxx>
CommitDate: Fri, 7 May 2010 15:31:17 -0700
x86: Avoid check hlt for newer cpus
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@xxxxxxxxxxxxxxx>
LKML-Reference: <1273269585-14346-1-git-send-email-jacob.jun.pan@xxxxxxxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
---
arch/x86/kernel/cpu/bugs.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 01a2652..c39576c 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -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... ");
--
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