1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright 2019 ARM Ltd. 4 * 5 * Generic implementation of update_vsyscall and update_vsyscall_tz. 6 * 7 * Based on the x86 specific implementation. 8 */ 9 10 #include <linux/hrtimer.h> 11 #include <linux/timekeeper_internal.h> 12 #include <vdso/datapage.h> 13 #include <vdso/helpers.h> 14 #include <vdso/vsyscall.h> 15 16 static inline void update_vdso_data(struct vdso_data *vdata, 17 struct timekeeper *tk) 18 { 19 struct vdso_timestamp *vdso_ts; 20 u64 nsec; 21 22 vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last; 23 vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask; 24 vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult; 25 vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift; 26 vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last; 27 vdata[CS_RAW].mask = tk->tkr_raw.mask; 28 vdata[CS_RAW].mult = tk->tkr_raw.mult; 29 vdata[CS_RAW].shift = tk->tkr_raw.shift; 30 31 /* CLOCK_REALTIME */ 32 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME]; 33 vdso_ts->sec = tk->xtime_sec; 34 vdso_ts->nsec = tk->tkr_mono.xtime_nsec; 35 36 /* CLOCK_MONOTONIC */ 37 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC]; 38 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; 39 40 nsec = tk->tkr_mono.xtime_nsec; 41 nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift); 42 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { 43 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift); 44 vdso_ts->sec++; 45 } 46 vdso_ts->nsec = nsec; 47 48 /* CLOCK_MONOTONIC_RAW */ 49 vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW]; 50 vdso_ts->sec = tk->raw_sec; 51 vdso_ts->nsec = tk->tkr_raw.xtime_nsec; 52 53 /* CLOCK_BOOTTIME */ 54 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME]; 55 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; 56 nsec = tk->tkr_mono.xtime_nsec; 57 nsec += ((u64)(tk->wall_to_monotonic.tv_nsec + 58 ktime_to_ns(tk->offs_boot)) << tk->tkr_mono.shift); 59 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { 60 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift); 61 vdso_ts->sec++; 62 } 63 vdso_ts->nsec = nsec; 64 65 /* CLOCK_TAI */ 66 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI]; 67 vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset; 68 vdso_ts->nsec = tk->tkr_mono.xtime_nsec; 69 70 /* 71 * Read without the seqlock held by clock_getres(). 72 * Note: No need to have a second copy. 73 */ 74 WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution); 75 } 76 77 void update_vsyscall(struct timekeeper *tk) 78 { 79 struct vdso_data *vdata = __arch_get_k_vdso_data(); 80 struct vdso_timestamp *vdso_ts; 81 u64 nsec; 82 83 if (__arch_update_vdso_data()) { 84 /* 85 * Some architectures might want to skip the update of the 86 * data page. 87 */ 88 return; 89 } 90 91 /* copy vsyscall data */ 92 vdso_write_begin(vdata); 93 94 vdata[CS_HRES_COARSE].clock_mode = __arch_get_clock_mode(tk); 95 vdata[CS_RAW].clock_mode = __arch_get_clock_mode(tk); 96 97 /* CLOCK_REALTIME_COARSE */ 98 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE]; 99 vdso_ts->sec = tk->xtime_sec; 100 vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; 101 102 /* CLOCK_MONOTONIC_COARSE */ 103 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE]; 104 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; 105 nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; 106 nsec = nsec + tk->wall_to_monotonic.tv_nsec; 107 vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec); 108 109 if (__arch_use_vsyscall(vdata)) 110 update_vdso_data(vdata, tk); 111 112 __arch_update_vsyscall(vdata, tk); 113 114 vdso_write_end(vdata); 115 116 __arch_sync_vdso_data(vdata); 117 } 118 119 void update_vsyscall_tz(void) 120 { 121 struct vdso_data *vdata = __arch_get_k_vdso_data(); 122 123 if (__arch_use_vsyscall(vdata)) { 124 vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest; 125 vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime; 126 } 127 128 __arch_sync_vdso_data(vdata); 129 } 130