diff options
Diffstat (limited to 'arch/x86_64/kernel/tsc_64.c')
| -rw-r--r-- | arch/x86_64/kernel/tsc_64.c | 207 |
1 files changed, 0 insertions, 207 deletions
diff --git a/arch/x86_64/kernel/tsc_64.c b/arch/x86_64/kernel/tsc_64.c deleted file mode 100644 index 2a59bde663f..00000000000 --- a/arch/x86_64/kernel/tsc_64.c +++ /dev/null @@ -1,207 +0,0 @@ -#include <linux/kernel.h> -#include <linux/sched.h> -#include <linux/interrupt.h> -#include <linux/init.h> -#include <linux/clocksource.h> -#include <linux/time.h> -#include <linux/acpi.h> -#include <linux/cpufreq.h> - -#include <asm/timex.h> - -static int notsc __initdata = 0; - -unsigned int cpu_khz; /* TSC clocks / usec, not used here */ -EXPORT_SYMBOL(cpu_khz); -unsigned int tsc_khz; -EXPORT_SYMBOL(tsc_khz); - -static unsigned int cyc2ns_scale __read_mostly; - -void set_cyc2ns_scale(unsigned long khz) -{ - cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / khz; -} - -static unsigned long long cycles_2_ns(unsigned long long cyc) -{ - return (cyc * cyc2ns_scale) >> NS_SCALE; -} - -unsigned long long sched_clock(void) -{ - unsigned long a = 0; - - /* Could do CPU core sync here. Opteron can execute rdtsc speculatively, - * which means it is not completely exact and may not be monotonous - * between CPUs. But the errors should be too small to matter for - * scheduling purposes. - */ - - rdtscll(a); - return cycles_2_ns(a); -} - -static int tsc_unstable; - -inline int check_tsc_unstable(void) -{ - return tsc_unstable; -} -#ifdef CONFIG_CPU_FREQ - -/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency - * changes. - * - * RED-PEN: On SMP we assume all CPUs run with the same frequency. It's - * not that important because current Opteron setups do not support - * scaling on SMP anyroads. - * - * Should fix up last_tsc too. Currently gettimeofday in the - * first tick after the change will be slightly wrong. - */ - -static unsigned int ref_freq; -static unsigned long loops_per_jiffy_ref; -static unsigned long tsc_khz_ref; - -static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, - void *data) -{ - struct cpufreq_freqs *freq = data; - unsigned long *lpj, dummy; - - if (cpu_has(&cpu_data[freq->cpu], X86_FEATURE_CONSTANT_TSC)) - return 0; - - lpj = &dummy; - if (!(freq->flags & CPUFREQ_CONST_LOOPS)) -#ifdef CONFIG_SMP - lpj = &cpu_data[freq->cpu].loops_per_jiffy; -#else - lpj = &boot_cpu_data.loops_per_jiffy; -#endif - - if (!ref_freq) { - ref_freq = freq->old; - loops_per_jiffy_ref = *lpj; - tsc_khz_ref = tsc_khz; - } - if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || - (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) || - (val == CPUFREQ_RESUMECHANGE)) { - *lpj = - cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new); - - tsc_khz = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new); - if (!(freq->flags & CPUFREQ_CONST_LOOPS)) - mark_tsc_unstable("cpufreq changes"); - } - - set_cyc2ns_scale(tsc_khz_ref); - - return 0; -} - -static struct notifier_block time_cpufreq_notifier_block = { - .notifier_call = time_cpufreq_notifier -}; - -static int __init cpufreq_tsc(void) -{ - cpufreq_register_notifier(&time_cpufreq_notifier_block, - CPUFREQ_TRANSITION_NOTIFIER); - return 0; -} - -core_initcall(cpufreq_tsc); - -#endif - -/* - * Make an educated guess if the TSC is trustworthy and synchronized - * over all CPUs. - */ -__cpuinit int unsynchronized_tsc(void) -{ - if (tsc_unstable) - return 1; - -#ifdef CONFIG_SMP - if (apic_is_clustered_box()) - return 1; -#endif - /* Most intel systems have synchronized TSCs except for - multi node systems */ - if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) { -#ifdef CONFIG_ACPI - /* But TSC doesn't tick in C3 so don't use it there */ - if (acpi_gbl_FADT.header.length > 0 && - acpi_gbl_FADT.C3latency < 1000) - return 1; -#endif - return 0; - } - - /* Assume multi socket systems are not synchronized */ - return num_present_cpus() > 1; -} - -int __init notsc_setup(char *s) -{ - notsc = 1; - return 1; -} - -__setup("notsc", notsc_setup); - - -/* clock source code: */ -static cycle_t read_tsc(void) -{ - cycle_t ret = (cycle_t)get_cycles_sync(); - return ret; -} - -static cycle_t __vsyscall_fn vread_tsc(void) -{ - cycle_t ret = (cycle_t)get_cycles_sync(); - return ret; -} - -static struct clocksource clocksource_tsc = { - .name = "tsc", - .rating = 300, - .read = read_tsc, - .mask = CLOCKSOURCE_MASK(64), - .shift = 22, - .flags = CLOCK_SOURCE_IS_CONTINUOUS | - CLOCK_SOURCE_MUST_VERIFY, - .vread = vread_tsc, -}; - -void mark_tsc_unstable(char *reason) -{ - if (!tsc_unstable) { - tsc_unstable = 1; - printk("Marking TSC unstable due to %s\n", reason); - /* Change only the rating, when not registered */ - if (clocksource_tsc.mult) - clocksource_change_rating(&clocksource_tsc, 0); - else - clocksource_tsc.rating = 0; - } -} -EXPORT_SYMBOL_GPL(mark_tsc_unstable); - -void __init init_tsc_clocksource(void) -{ - if (!notsc) { - clocksource_tsc.mult = clocksource_khz2mult(tsc_khz, - clocksource_tsc.shift); - if (check_tsc_unstable()) - clocksource_tsc.rating = 0; - - clocksource_register(&clocksource_tsc); - } -} |