// SPDX-License-Identifier: GPL-2.0 /* * Generic userspace implementations of gettimeofday() and similar. */ #include <vdso/datapage.h> #include <vdso/helpers.h> #ifndef vdso_calc_delta /* * Default implementation which works for all sane clocksources. That * obviously excludes x86/TSC. */ static __always_inline u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) { return ((cycles - last) & mask) * mult; } #endif #ifndef vdso_shift_ns static __always_inline u64 vdso_shift_ns(u64 ns, u32 shift) { return ns >> shift; } #endif #ifndef __arch_vdso_hres_capable static inline bool __arch_vdso_hres_capable(void) { return true; } #endif #ifndef vdso_clocksource_ok static inline bool vdso_clocksource_ok(const struct vdso_data *vd) { return vd->clock_mode != VDSO_CLOCKMODE_NONE; } #endif #ifndef vdso_cycles_ok static inline bool vdso_cycles_ok(u64 cycles) { return true; } #endif #ifdef CONFIG_TIME_NS static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_data *vd; const struct timens_offset *offs = &vdns->offset[clk]; const struct vdso_timestamp *vdso_ts; u64 cycles, last, ns; u32 seq; s64 sec; vd = vdns - (clk == CLOCK_MONOTONIC_RAW ? CS_RAW : CS_HRES_COARSE); vd = __arch_get_timens_vdso_data(vd); if (clk != CLOCK_MONOTONIC_RAW) vd = &vd[CS_HRES_COARSE]; else vd = &vd[CS_RAW]; vdso_ts = &vd->basetime[clk]; do { seq = vdso_read_begin(vd); if (unlikely(!vdso_clocksource_ok(vd))) return -1; cycles = __arch_get_hw_counter(vd->clock_mode, vd); if (unlikely(!vdso_cycles_ok(cycles))) return -1; ns = vdso_ts->nsec; last = vd->cycle_last; ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult); ns = vdso_shift_ns(ns, vd->shift); sec = vdso_ts->sec; } while (unlikely(vdso_read_retry(vd, seq))); /* Add the namespace offset */ sec += offs->sec; ns += offs->nsec; /* * Do this outside the loop: a race inside the loop could result * in __iter_div_u64_rem() being extremely slow. */ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); ts->tv_nsec = ns; return 0; } #else static __always_inline const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd) { return NULL; } static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_t clk, struct __kernel_timespec *ts) { return -EINVAL; } #endif static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; u64 cycles, last, sec, ns; u32 seq; /* Allows to compile the high resolution parts out */ if (!__arch_vdso_hres_capable()) return -1; do { /* * Open coded to handle VDSO_CLOCKMODE_TIMENS. Time namespace * enabled tasks have a special VVAR page installed which * has vd->seq set to 1 and vd->clock_mode set to * VDSO_CLOCKMODE_TIMENS. For non time namespace affected tasks * this does not affect performance because if vd->seq is * odd, i.e. a concurrent update is in progress the extra * check for vd->clock_mode is just a few extra * instructions while spin waiting for vd->seq to become * even again. */ while (unlikely((seq = READ_ONCE(vd->seq)) & 1)) { if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) return do_hres_timens(vd, clk, ts); cpu_relax(); } smp_rmb(); if (unlikely(!vdso_clocksource_ok(vd))) return -1; cycles = __arch_get_hw_counter(vd->clock_mode, vd); if (unlikely(!vdso_cycles_ok(cycles))) return -1; ns = vdso_ts->nsec; last = vd->cycle_last; ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult); ns = vdso_shift_ns(ns, vd->shift); sec = vdso_ts->sec; } while (unlikely(vdso_read_retry(vd, seq))); /* * Do this outside the loop: a race inside the loop could result * in __iter_div_u64_rem() being extremely slow. */ ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns); ts->tv_nsec = ns; return 0; } #ifdef CONFIG_TIME_NS static __always_inline int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_data *vd = __arch_get_timens_vdso_data(vdns); const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; const struct timens_offset *offs = &vdns->offset[clk]; u64 nsec; s64 sec; s32 seq; do { seq = vdso_read_begin(vd); sec = vdso_ts->sec; nsec = vdso_ts->nsec; } while (unlikely(vdso_read_retry(vd, seq))); /* Add the namespace offset */ sec += offs->sec; nsec += offs->nsec; /* * Do this outside the loop: a race inside the loop could result * in __iter_div_u64_rem() being extremely slow. */ ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec); ts->tv_nsec = nsec; return 0; } #else static __always_inline int do_coarse_timens(const struct vdso_data *vdns, clockid_t clk, struct __kernel_timespec *ts) { return -1; } #endif static __always_inline int do_coarse(const struct vdso_data *vd, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; u32 seq; do { /* * Open coded to handle VDSO_CLOCK_TIMENS. See comment in * do_hres(). */ while ((seq = READ_ONCE(vd->seq)) & 1) { if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) return do_coarse_timens(vd, clk, ts); cpu_relax(); } smp_rmb(); ts->tv_sec = vdso_ts->sec; ts->tv_nsec = vdso_ts->nsec; } while (unlikely(vdso_read_retry(vd, seq))); return 0; } static __always_inline int __cvdso_clock_gettime_common(const struct vdso_data *vd, clockid_t clock, struct __kernel_timespec *ts) { u32 msk; /* Check for negative values or invalid clocks */ if (unlikely((u32) clock >= MAX_CLOCKS)) return -1; /* * Convert the clockid to a bitmask and use it to check which * clocks are handled in the VDSO directly. */ msk = 1U << clock; if (likely(msk & VDSO_HRES)) vd = &vd[CS_HRES_COARSE]; else if (msk & VDSO_COARSE) return do_coarse(&vd[CS_HRES_COARSE], clock, ts); else if (msk & VDSO_RAW) vd = &vd[CS_RAW]; else return -1; return do_hres(vd, clock, ts); } static __maybe_unused int __cvdso_clock_gettime_data(const struct vdso_data *vd, clockid_t clock, struct __kernel_timespec *ts) { int ret = __cvdso_clock_gettime_common(vd, clock, ts); if (unlikely(ret)) return clock_gettime_fallback(clock, ts); return 0; } static __maybe_unused int __cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) { return __cvdso_clock_gettime_data(__arch_get_vdso_data(), clock, ts); } #ifdef BUILD_VDSO32 static __maybe_unused int __cvdso_clock_gettime32_data(const struct vdso_data *vd, clockid_t clock, struct old_timespec32 *res) { struct __kernel_timespec ts; int ret; ret = __cvdso_clock_gettime_common(vd, clock, &ts); if (unlikely(ret)) return clock_gettime32_fallback(clock, res); /* For ret == 0 */ res->tv_sec = ts.tv_sec; res->tv_nsec = ts.tv_nsec; return ret; } static __maybe_unused int __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res) { return __cvdso_clock_gettime32_data(__arch_get_vdso_data(), clock, res); } #endif /* BUILD_VDSO32 */ static __maybe_unused int __cvdso_gettimeofday_data(const struct vdso_data *vd, struct __kernel_old_timeval *tv, struct timezone *tz) { if (likely(tv != NULL)) { struct __kernel_timespec ts; if (do_hres(&vd[CS_HRES_COARSE], CLOCK_REALTIME, &ts)) return gettimeofday_fallback(tv, tz); tv->tv_sec = ts.tv_sec; tv->tv_usec = (u32)ts.tv_nsec / NSEC_PER_USEC; } if (unlikely(tz != NULL)) { if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) vd = __arch_get_timens_vdso_data(vd); tz->tz_minuteswest = vd[CS_HRES_COARSE].tz_minuteswest; tz->tz_dsttime = vd[CS_HRES_COARSE].tz_dsttime; } return 0; } static __maybe_unused int __cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { return __cvdso_gettimeofday_data(__arch_get_vdso_data(), tv, tz); } #ifdef VDSO_HAS_TIME static __maybe_unused __kernel_old_time_t __cvdso_time_data(const struct vdso_data *vd, __kernel_old_time_t *time) { __kernel_old_time_t t; if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) vd = __arch_get_timens_vdso_data(vd); t = READ_ONCE(vd[CS_HRES_COARSE].basetime[CLOCK_REALTIME].sec); if (time) *time = t; return t; } static __maybe_unused __kernel_old_time_t __cvdso_time(__kernel_old_time_t *time) { return __cvdso_time_data(__arch_get_vdso_data(), time); } #endif /* VDSO_HAS_TIME */ #ifdef VDSO_HAS_CLOCK_GETRES static __maybe_unused int __cvdso_clock_getres_common(const struct vdso_data *vd, clockid_t clock, struct __kernel_timespec *res) { u32 msk; u64 ns; /* Check for negative values or invalid clocks */ if (unlikely((u32) clock >= MAX_CLOCKS)) return -1; if (IS_ENABLED(CONFIG_TIME_NS) && vd->clock_mode == VDSO_CLOCKMODE_TIMENS) vd = __arch_get_timens_vdso_data(vd); /* * Convert the clockid to a bitmask and use it to check which * clocks are handled in the VDSO directly. */ msk = 1U << clock; if (msk & (VDSO_HRES | VDSO_RAW)) { /* * Preserves the behaviour of posix_get_hrtimer_res(). */ ns = READ_ONCE(vd[CS_HRES_COARSE].hrtimer_res); } else if (msk & VDSO_COARSE) { /* * Preserves the behaviour of posix_get_coarse_res(). */ ns = LOW_RES_NSEC; } else { return -1; } if (likely(res)) { res->tv_sec = 0; res->tv_nsec = ns; } return 0; } static __maybe_unused int __cvdso_clock_getres_data(const struct vdso_data *vd, clockid_t clock, struct __kernel_timespec *res) { int ret = __cvdso_clock_getres_common(vd, clock, res); if (unlikely(ret)) return clock_getres_fallback(clock, res); return 0; } static __maybe_unused int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res) { return __cvdso_clock_getres_data(__arch_get_vdso_data(), clock, res); } #ifdef BUILD_VDSO32 static __maybe_unused int __cvdso_clock_getres_time32_data(const struct vdso_data *vd, clockid_t clock, struct old_timespec32 *res) { struct __kernel_timespec ts; int ret; ret = __cvdso_clock_getres_common(vd, clock, &ts); if (unlikely(ret)) return clock_getres32_fallback(clock, res); if (likely(res)) { res->tv_sec = ts.tv_sec; res->tv_nsec = ts.tv_nsec; } return ret; } static __maybe_unused int __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res) { return __cvdso_clock_getres_time32_data(__arch_get_vdso_data(), clock, res); } #endif /* BUILD_VDSO32 */ #endif /* VDSO_HAS_CLOCK_GETRES */