| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Generic userspace implementations of gettimeofday() and similar. |
| */ |
| #include <vdso/datapage.h> |
| #include <vdso/helpers.h> |
| |
| #ifndef vdso_calc_ns |
| |
| #ifdef VDSO_DELTA_NOMASK |
| # define VDSO_DELTA_MASK(vd) ULLONG_MAX |
| #else |
| # define VDSO_DELTA_MASK(vd) (vd->mask) |
| #endif |
| |
| #ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT |
| static __always_inline bool vdso_delta_ok(const struct vdso_data *vd, u64 delta) |
| { |
| return delta < vd->max_cycles; |
| } |
| #else |
| static __always_inline bool vdso_delta_ok(const struct vdso_data *vd, u64 delta) |
| { |
| return true; |
| } |
| #endif |
| |
| #ifndef vdso_shift_ns |
| static __always_inline u64 vdso_shift_ns(u64 ns, u32 shift) |
| { |
| return ns >> shift; |
| } |
| #endif |
| |
| /* |
| * Default implementation which works for all sane clocksources. That |
| * obviously excludes x86/TSC. |
| */ |
| static __always_inline u64 vdso_calc_ns(const struct vdso_data *vd, u64 cycles, u64 base) |
| { |
| u64 delta = (cycles - vd->cycle_last) & VDSO_DELTA_MASK(vd); |
| |
| if (likely(vdso_delta_ok(vd, delta))) |
| return vdso_shift_ns((delta * vd->mult) + base, vd->shift); |
| |
| return mul_u64_u32_add_u64_shr(delta, vd->mult, base, vd->shift); |
| } |
| #endif /* vdso_calc_ns */ |
| |
| #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 timens_offset *offs = &vdns->offset[clk]; |
| const struct vdso_timestamp *vdso_ts; |
| const struct vdso_data *vd; |
| u64 cycles, 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_calc_ns(vd, cycles, vdso_ts->nsec); |
| 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, sec, ns; |
| u32 seq; |
| |
| /* Allows to compile the high resolution parts out */ |
| if (!__arch_vdso_hres_capable()) |
| return -1; |
| |
| do { |
| /* |
| * Open coded function vdso_read_begin() 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_calc_ns(vd, cycles, vdso_ts->nsec); |
| 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 function vdso_read_begin() 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 */ |