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-rw-r--r--kernel/time/vsyscall.c133
1 files changed, 133 insertions, 0 deletions
diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c
new file mode 100644
index 000000000000..a80893180826
--- /dev/null
+++ b/kernel/time/vsyscall.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 ARM Ltd.
+ *
+ * Generic implementation of update_vsyscall and update_vsyscall_tz.
+ *
+ * Based on the x86 specific implementation.
+ */
+
+#include <linux/hrtimer.h>
+#include <linux/timekeeper_internal.h>
+#include <vdso/datapage.h>
+#include <vdso/helpers.h>
+#include <vdso/vsyscall.h>
+
+static inline void update_vdso_data(struct vdso_data *vdata,
+ struct timekeeper *tk)
+{
+ struct vdso_timestamp *vdso_ts;
+ u64 nsec;
+
+ vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last;
+ vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask;
+ vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult;
+ vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift;
+ vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last;
+ vdata[CS_RAW].mask = tk->tkr_raw.mask;
+ vdata[CS_RAW].mult = tk->tkr_raw.mult;
+ vdata[CS_RAW].shift = tk->tkr_raw.shift;
+
+ /* CLOCK_REALTIME */
+ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME];
+ vdso_ts->sec = tk->xtime_sec;
+ vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
+
+ /* CLOCK_MONOTONIC */
+ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC];
+ vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
+
+ nsec = tk->tkr_mono.xtime_nsec;
+ nsec += ((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
+ while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
+ nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
+ vdso_ts->sec++;
+ }
+ vdso_ts->nsec = nsec;
+
+ /* CLOCK_MONOTONIC_RAW */
+ vdso_ts = &vdata[CS_RAW].basetime[CLOCK_MONOTONIC_RAW];
+ vdso_ts->sec = tk->raw_sec;
+ vdso_ts->nsec = tk->tkr_raw.xtime_nsec;
+
+ /* CLOCK_BOOTTIME */
+ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_BOOTTIME];
+ vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
+ nsec = tk->tkr_mono.xtime_nsec;
+ nsec += ((u64)(tk->wall_to_monotonic.tv_nsec +
+ ktime_to_ns(tk->offs_boot)) << tk->tkr_mono.shift);
+ while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
+ nsec -= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift);
+ vdso_ts->sec++;
+ }
+ vdso_ts->nsec = nsec;
+
+ /* CLOCK_TAI */
+ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_TAI];
+ vdso_ts->sec = tk->xtime_sec + (s64)tk->tai_offset;
+ vdso_ts->nsec = tk->tkr_mono.xtime_nsec;
+
+ /*
+ * Read without the seqlock held by clock_getres().
+ * Note: No need to have a second copy.
+ */
+ WRITE_ONCE(vdata[CS_HRES_COARSE].hrtimer_res, hrtimer_resolution);
+}
+
+void update_vsyscall(struct timekeeper *tk)
+{
+ struct vdso_data *vdata = __arch_get_k_vdso_data();
+ struct vdso_timestamp *vdso_ts;
+ u64 nsec;
+
+ if (__arch_update_vdso_data()) {
+ /*
+ * Some architectures might want to skip the update of the
+ * data page.
+ */
+ return;
+ }
+
+ /* copy vsyscall data */
+ vdso_write_begin(vdata);
+
+ vdata[CS_HRES_COARSE].clock_mode = __arch_get_clock_mode(tk);
+ vdata[CS_RAW].clock_mode = __arch_get_clock_mode(tk);
+
+ /* CLOCK_REALTIME_COARSE */
+ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_REALTIME_COARSE];
+ vdso_ts->sec = tk->xtime_sec;
+ vdso_ts->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+
+ /* CLOCK_MONOTONIC_COARSE */
+ vdso_ts = &vdata[CS_HRES_COARSE].basetime[CLOCK_MONOTONIC_COARSE];
+ vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
+ nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
+ nsec = nsec + tk->wall_to_monotonic.tv_nsec;
+ while (nsec >= NSEC_PER_SEC) {
+ nsec = nsec - NSEC_PER_SEC;
+ vdso_ts->sec++;
+ }
+ vdso_ts->nsec = nsec;
+
+ if (__arch_use_vsyscall(vdata))
+ update_vdso_data(vdata, tk);
+
+ __arch_update_vsyscall(vdata, tk);
+
+ vdso_write_end(vdata);
+
+ __arch_sync_vdso_data(vdata);
+}
+
+void update_vsyscall_tz(void)
+{
+ struct vdso_data *vdata = __arch_get_k_vdso_data();
+
+ if (__arch_use_vsyscall(vdata)) {
+ vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest;
+ vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
+ }
+
+ __arch_sync_vdso_data(vdata);
+}

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