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, sec; 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_MONOTONIC */ 32 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC]; 33 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; 34 35 nsec = tk->tkr_mono.xtime_nsec; 36 nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift); 37 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { 38 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift); 39 vdso_ts->sec++; 40 } 41 vdso_ts->nsec = nsec; 42 43 /* Copy MONOTONIC time for BOOTTIME */ 44 sec = vdso_ts->sec; 45 /* Add the boot offset */ 46 sec += tk->monotonic_to_boot.tv_sec; 47 nsec += (u64)tk->monotonic_to_boot.tv_nsec << tk->tkr_mono.shift; 48 49 /* CLOCK_BOOTTIME */ 50 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME]; 51 vdso_ts->sec = sec; 52 53 while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { 54 nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift); 55 vdso_ts->sec++; 56 } 57 vdso_ts->nsec = nsec; 58 59 /* CLOCK_MONOTONIC_RAW */ 60 vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW]; 61 vdso_ts->sec = tk->raw_sec; 62 vdso_ts->nsec = tk->tkr_raw.xtime_nsec; 63 64 /* CLOCK_TAI */ 65 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI]; 66 vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset; 67 vdso_ts->nsec = tk->tkr_mono.xtime_nsec; 68 } 69 70 void update_vsyscall(struct timekeeper *tk) 71 { 72 struct vdso_data *vdata = __arch_get_k_vdso_data(); 73 struct vdso_timestamp *vdso_ts; 74 u64 nsec; 75 76 /* copy vsyscall data */ 77 vdso_write_begin(vdata); 78 79 vdata[CS_HRES_COARSE].clock_mode = __arch_get_clock_mode(tk); 80 vdata[CS_RAW].clock_mode = __arch_get_clock_mode(tk); 81 82 /* CLOCK_REALTIME also required for time() */ 83 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME]; 84 vdso_ts->sec = tk->xtime_sec; 85 vdso_ts->nsec = tk->tkr_mono.xtime_nsec; 86 87 /* CLOCK_REALTIME_COARSE */ 88 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE]; 89 vdso_ts->sec = tk->xtime_sec; 90 vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; 91 92 /* CLOCK_MONOTONIC_COARSE */ 93 vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE]; 94 vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; 95 nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; 96 nsec = nsec + tk->wall_to_monotonic.tv_nsec; 97 vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec); 98 99 /* 100 * Read without the seqlock held by clock_getres(). 101 * Note: No need to have a second copy. 102 */ 103 WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution); 104 105 /* 106 * Architectures can opt out of updating the high resolution part 107 * of the VDSO. 108 */ 109 if (__arch_update_vdso_data()) 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 vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest; 124 vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime; 125 126 __arch_sync_vdso_data(vdata); 127 } 128