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authorVojtech Pavlik <vojtech@suse.cz>2006-09-26 10:52:28 +0200
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 10:52:28 +0200
commitc08c820508233b424deab3302bc404bbecc6493a (patch)
treed6ed79fb2d03513f6c71fc7e47705c4a19512f53 /arch/x86_64/kernel/time.c
parenta670fad0adb1cc6202a607d250f10bd380593905 (diff)
[PATCH] Add the vgetcpu vsyscall
This patch adds a vgetcpu vsyscall, which depending on the CPU RDTSCP capability uses either the RDTSCP or CPUID to obtain a CPU and node numbers and pass them to the program. AK: Lots of changes over Vojtech's original code: Better prototype for vgetcpu() It's better to pass the cpu / node numbers as separate arguments to avoid mistakes when going from SMP to NUMA. Also add a fast time stamp based cache using a user supplied argument to speed things more up. Use fast method from Chuck Ebbert to retrieve node/cpu from GDT limit instead of CPUID Made sure RDTSCP init is always executed after node is known. Drop printk Signed-off-by: Vojtech Pavlik <vojtech@suse.cz> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/kernel/time.c')
-rw-r--r--arch/x86_64/kernel/time.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 97b9e46d199..560ed944dc0 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -899,12 +899,8 @@ static int __cpuinit
time_cpu_notifier(struct notifier_block *nb, unsigned long action, void *hcpu)
{
unsigned cpu = (unsigned long) hcpu;
- if (action == CPU_ONLINE &&
- cpu_has(&cpu_data[cpu], X86_FEATURE_RDTSCP)) {
- unsigned p;
- p = smp_processor_id() | (cpu_to_node(smp_processor_id())<<12);
- write_rdtscp_aux(p);
- }
+ if (action == CPU_ONLINE)
+ vsyscall_set_cpu(cpu);
return NOTIFY_DONE;
}
@@ -993,6 +989,11 @@ void time_init_gtod(void)
if (unsynchronized_tsc())
notsc = 1;
+ if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
+ vgetcpu_mode = VGETCPU_RDTSCP;
+ else
+ vgetcpu_mode = VGETCPU_LSL;
+
if (vxtime.hpet_address && notsc) {
timetype = hpet_use_timer ? "HPET" : "PIT/HPET";
if (hpet_use_timer)