From c08c820508233b424deab3302bc404bbecc6493a Mon Sep 17 00:00:00 2001 From: Vojtech Pavlik Date: Tue, 26 Sep 2006 10:52:28 +0200 Subject: [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 Signed-off-by: Andi Kleen --- arch/x86_64/kernel/time.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'arch/x86_64/kernel/time.c') diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c index 97b9e46d..560ed94 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) -- cgit v1.1