diff options
Diffstat (limited to 'arch/x86/vdso/vclock_gettime.c')
-rw-r--r-- | arch/x86/vdso/vclock_gettime.c | 351 |
1 files changed, 0 insertions, 351 deletions
diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c deleted file mode 100644 index 979332275..000000000 --- a/arch/x86/vdso/vclock_gettime.c +++ /dev/null @@ -1,351 +0,0 @@ -/* - * Copyright 2006 Andi Kleen, SUSE Labs. - * Subject to the GNU Public License, v.2 - * - * Fast user context implementation of clock_gettime, gettimeofday, and time. - * - * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net> - * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany - * - * The code should have no internal unresolved relocations. - * Check with readelf after changing. - */ - -#include <uapi/linux/time.h> -#include <asm/vgtod.h> -#include <asm/hpet.h> -#include <asm/vvar.h> -#include <asm/unistd.h> -#include <asm/msr.h> -#include <linux/math64.h> -#include <linux/time.h> - -#define gtod (&VVAR(vsyscall_gtod_data)) - -extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts); -extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz); -extern time_t __vdso_time(time_t *t); - -#ifdef CONFIG_HPET_TIMER -extern u8 hpet_page - __attribute__((visibility("hidden"))); - -static notrace cycle_t vread_hpet(void) -{ - return *(const volatile u32 *)(&hpet_page + HPET_COUNTER); -} -#endif - -#ifndef BUILD_VDSO32 - -#include <linux/kernel.h> -#include <asm/vsyscall.h> -#include <asm/fixmap.h> -#include <asm/pvclock.h> - -notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) -{ - long ret; - asm("syscall" : "=a" (ret) : - "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory"); - return ret; -} - -notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) -{ - long ret; - - asm("syscall" : "=a" (ret) : - "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory"); - return ret; -} - -#ifdef CONFIG_PARAVIRT_CLOCK - -static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu) -{ - const struct pvclock_vsyscall_time_info *pvti_base; - int idx = cpu / (PAGE_SIZE/PVTI_SIZE); - int offset = cpu % (PAGE_SIZE/PVTI_SIZE); - - BUG_ON(PVCLOCK_FIXMAP_BEGIN + idx > PVCLOCK_FIXMAP_END); - - pvti_base = (struct pvclock_vsyscall_time_info *) - __fix_to_virt(PVCLOCK_FIXMAP_BEGIN+idx); - - return &pvti_base[offset]; -} - -static notrace cycle_t vread_pvclock(int *mode) -{ - const struct pvclock_vsyscall_time_info *pvti; - cycle_t ret; - u64 last; - u32 version; - u8 flags; - unsigned cpu, cpu1; - - - /* - * Note: hypervisor must guarantee that: - * 1. cpu ID number maps 1:1 to per-CPU pvclock time info. - * 2. that per-CPU pvclock time info is updated if the - * underlying CPU changes. - * 3. that version is increased whenever underlying CPU - * changes. - * - */ - do { - cpu = __getcpu() & VGETCPU_CPU_MASK; - /* TODO: We can put vcpu id into higher bits of pvti.version. - * This will save a couple of cycles by getting rid of - * __getcpu() calls (Gleb). - */ - - pvti = get_pvti(cpu); - - version = __pvclock_read_cycles(&pvti->pvti, &ret, &flags); - - /* - * Test we're still on the cpu as well as the version. - * We could have been migrated just after the first - * vgetcpu but before fetching the version, so we - * wouldn't notice a version change. - */ - cpu1 = __getcpu() & VGETCPU_CPU_MASK; - } while (unlikely(cpu != cpu1 || - (pvti->pvti.version & 1) || - pvti->pvti.version != version)); - - if (unlikely(!(flags & PVCLOCK_TSC_STABLE_BIT))) - *mode = VCLOCK_NONE; - - /* refer to tsc.c read_tsc() comment for rationale */ - last = gtod->cycle_last; - - if (likely(ret >= last)) - return ret; - - return last; -} -#endif - -#else - -notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) -{ - long ret; - - asm( - "mov %%ebx, %%edx \n" - "mov %2, %%ebx \n" - "call __kernel_vsyscall \n" - "mov %%edx, %%ebx \n" - : "=a" (ret) - : "0" (__NR_clock_gettime), "g" (clock), "c" (ts) - : "memory", "edx"); - return ret; -} - -notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz) -{ - long ret; - - asm( - "mov %%ebx, %%edx \n" - "mov %2, %%ebx \n" - "call __kernel_vsyscall \n" - "mov %%edx, %%ebx \n" - : "=a" (ret) - : "0" (__NR_gettimeofday), "g" (tv), "c" (tz) - : "memory", "edx"); - return ret; -} - -#ifdef CONFIG_PARAVIRT_CLOCK - -static notrace cycle_t vread_pvclock(int *mode) -{ - *mode = VCLOCK_NONE; - return 0; -} -#endif - -#endif - -notrace static cycle_t vread_tsc(void) -{ - cycle_t ret; - u64 last; - - /* - * Empirically, a fence (of type that depends on the CPU) - * before rdtsc is enough to ensure that rdtsc is ordered - * with respect to loads. The various CPU manuals are unclear - * as to whether rdtsc can be reordered with later loads, - * but no one has ever seen it happen. - */ - rdtsc_barrier(); - ret = (cycle_t)__native_read_tsc(); - - last = gtod->cycle_last; - - if (likely(ret >= last)) - return ret; - - /* - * GCC likes to generate cmov here, but this branch is extremely - * predictable (it's just a funciton of time and the likely is - * very likely) and there's a data dependence, so force GCC - * to generate a branch instead. I don't barrier() because - * we don't actually need a barrier, and if this function - * ever gets inlined it will generate worse code. - */ - asm volatile (""); - return last; -} - -notrace static inline u64 vgetsns(int *mode) -{ - u64 v; - cycles_t cycles; - - if (gtod->vclock_mode == VCLOCK_TSC) - cycles = vread_tsc(); -#ifdef CONFIG_HPET_TIMER - else if (gtod->vclock_mode == VCLOCK_HPET) - cycles = vread_hpet(); -#endif -#ifdef CONFIG_PARAVIRT_CLOCK - else if (gtod->vclock_mode == VCLOCK_PVCLOCK) - cycles = vread_pvclock(mode); -#endif - else - return 0; - v = (cycles - gtod->cycle_last) & gtod->mask; - return v * gtod->mult; -} - -/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */ -notrace static int __always_inline do_realtime(struct timespec *ts) -{ - unsigned long seq; - u64 ns; - int mode; - - do { - seq = gtod_read_begin(gtod); - mode = gtod->vclock_mode; - ts->tv_sec = gtod->wall_time_sec; - ns = gtod->wall_time_snsec; - ns += vgetsns(&mode); - ns >>= gtod->shift; - } while (unlikely(gtod_read_retry(gtod, seq))); - - ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); - ts->tv_nsec = ns; - - return mode; -} - -notrace static int __always_inline do_monotonic(struct timespec *ts) -{ - unsigned long seq; - u64 ns; - int mode; - - do { - seq = gtod_read_begin(gtod); - mode = gtod->vclock_mode; - ts->tv_sec = gtod->monotonic_time_sec; - ns = gtod->monotonic_time_snsec; - ns += vgetsns(&mode); - ns >>= gtod->shift; - } while (unlikely(gtod_read_retry(gtod, seq))); - - ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); - ts->tv_nsec = ns; - - return mode; -} - -notrace static void do_realtime_coarse(struct timespec *ts) -{ - unsigned long seq; - do { - seq = gtod_read_begin(gtod); - ts->tv_sec = gtod->wall_time_coarse_sec; - ts->tv_nsec = gtod->wall_time_coarse_nsec; - } while (unlikely(gtod_read_retry(gtod, seq))); -} - -notrace static void do_monotonic_coarse(struct timespec *ts) -{ - unsigned long seq; - do { - seq = gtod_read_begin(gtod); - ts->tv_sec = gtod->monotonic_time_coarse_sec; - ts->tv_nsec = gtod->monotonic_time_coarse_nsec; - } while (unlikely(gtod_read_retry(gtod, seq))); -} - -notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts) -{ - switch (clock) { - case CLOCK_REALTIME: - if (do_realtime(ts) == VCLOCK_NONE) - goto fallback; - break; - case CLOCK_MONOTONIC: - if (do_monotonic(ts) == VCLOCK_NONE) - goto fallback; - break; - case CLOCK_REALTIME_COARSE: - do_realtime_coarse(ts); - break; - case CLOCK_MONOTONIC_COARSE: - do_monotonic_coarse(ts); - break; - default: - goto fallback; - } - - return 0; -fallback: - return vdso_fallback_gettime(clock, ts); -} -int clock_gettime(clockid_t, struct timespec *) - __attribute__((weak, alias("__vdso_clock_gettime"))); - -notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz) -{ - if (likely(tv != NULL)) { - if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE)) - return vdso_fallback_gtod(tv, tz); - tv->tv_usec /= 1000; - } - if (unlikely(tz != NULL)) { - tz->tz_minuteswest = gtod->tz_minuteswest; - tz->tz_dsttime = gtod->tz_dsttime; - } - - return 0; -} -int gettimeofday(struct timeval *, struct timezone *) - __attribute__((weak, alias("__vdso_gettimeofday"))); - -/* - * This will break when the xtime seconds get inaccurate, but that is - * unlikely - */ -notrace time_t __vdso_time(time_t *t) -{ - /* This is atomic on x86 so we don't need any locks. */ - time_t result = ACCESS_ONCE(gtod->wall_time_sec); - - if (t) - *t = result; - return result; -} -int time(time_t *t) - __attribute__((weak, alias("__vdso_time"))); |