Messages in this thread | | | From | Andrew Lutomirski <> | Date | Wed, 3 Aug 2011 12:39:49 -0400 | Subject | Re: [PATCH 1/2] x86: Enable fast strings on Intel if BIOS hasn't already |
| |
On Wed, Aug 3, 2011 at 12:34 PM, Yu, Fenghua <fenghua.yu@intel.com> wrote: > > >> -----Original Message----- >> From: Andy Lutomirski [mailto:luto@MIT.EDU] >> Sent: Wednesday, August 03, 2011 8:47 AM >> To: x86@kernel.org; linux-kernel@vger.kernel.org >> Cc: Yu, Fenghua; Andy Lutomirski >> Subject: [PATCH 1/2] x86: Enable fast strings on Intel if BIOS hasn't >> already >> >> I have two Sandy Bridge systems and neither one enables fast strings >> in BIOS. I can't find anything in the manual that says that only >> BIOS should enable or disable the feature, so try to enable it at >> bootup. >> >> Signed-off-by: Andy Lutomirski <luto@mit.edu> >> --- >> arch/x86/kernel/cpu/intel.c | 17 +++++++++++++++-- >> 1 files changed, 15 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c >> index ed6086e..6b20fef 100644 >> --- a/arch/x86/kernel/cpu/intel.c >> +++ b/arch/x86/kernel/cpu/intel.c >> @@ -30,6 +30,7 @@ >> static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) >> { >> u64 misc_enable; >> + bool allow_fast_string = true; >> >> /* Unmask CPUID levels if masked: */ >> if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) { >> @@ -118,10 +119,11 @@ static void __cpuinit early_init_intel(struct >> cpuinfo_x86 *c) >> * (model 2) with the same problem. >> */ >> if (c->x86 == 15) { >> - rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> + allow_fast_string = false; >> + printk(KERN_INFO "kmemcheck: Disabling fast string >> operations\n"); > > Please don't move this printk() here. Keep it in the original place. If fast string bit is 0 already, we don't need to print the info.
I'll rework it.
> >> >> + rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> if (misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING) { >> - printk(KERN_INFO "kmemcheck: Disabling fast string >> operations\n"); >> >> misc_enable &= ~MSR_IA32_MISC_ENABLE_FAST_STRING; >> wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable); >> @@ -135,6 +137,17 @@ static void __cpuinit early_init_intel(struct >> cpuinfo_x86 *c) > > You also need to change the comment right before this code. With your patch, the comment is out-of-date.
Will do.
--Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |