[PATCH] x86: printk_time to use tsc before cpu_clock is ready

Yinghai Lu
2008-07-29T10:11:27Z

so can get tsc value on printk

need to apply after
[PATCH] printk_time: prepare stub for using other than cpu_clock

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