Messages in this thread | | | Subject | Re: [PATCH] x86: printk_time to use tsc before cpu_clock is ready | From | Peter Zijlstra <> | Date | Tue, 29 Jul 2008 12:13:07 +0200 |
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On Tue, 2008-07-29 at 03:09 -0700, Yinghai Lu wrote: > so can get tsc value on printk > > need to apply after > [PATCH] printk_time: prepare stub for using other than cpu_clock
You failed to mention why we want this... ;-)
> Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> > > --- > arch/x86/kernel/cpu/common.c | 11 +++++++++++ > arch/x86/kernel/cpu/common_64.c | 12 ++++++++++++ > 2 files changed, 23 insertions(+) > > Index: linux-2.6/arch/x86/kernel/cpu/common.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/cpu/common.c > +++ linux-2.6/arch/x86/kernel/cpu/common.c > @@ -617,6 +617,15 @@ __setup("clearcpuid=", setup_disablecpui > > cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE; > > +static unsigned long long tsc_clock(int cpu) > +{ > + unsigned long long t; > + > + rdtscll(t); > + > + return t; > +} > + > void __init early_cpu_init(void) > { > struct cpu_vendor_dev *cvdev; > @@ -627,6 +636,8 @@ void __init early_cpu_init(void) > cpu_devs[cvdev->vendor] = cvdev->cpu_dev; > > early_cpu_detect(); > + if (cpu_has_tsc) > + set_printk_time_clock(tsc_clock); > validate_pat_support(&boot_cpu_data); > } > > Index: linux-2.6/arch/x86/kernel/cpu/common_64.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/cpu/common_64.c > +++ linux-2.6/arch/x86/kernel/cpu/common_64.c > @@ -215,6 +215,15 @@ static void __init early_cpu_support_pri > } > } > > +static unsigned long long tsc_clock(int cpu) > +{ > + unsigned long long t; > + > + rdtscll(t); > + > + return t; > +} > + > static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c); > > void __init early_cpu_init(void) > @@ -227,6 +236,9 @@ void __init early_cpu_init(void) > cpu_devs[cvdev->vendor] = cvdev->cpu_dev; > early_cpu_support_print(); > early_identify_cpu(&boot_cpu_data); > + > + if (cpu_has_tsc) > + set_printk_time_clock(tsc_clock); > } > > /* Do some early cpuid on the boot CPU to get some parameter that are > -- > 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/
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