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Diffstat (limited to 'arch/tile/kernel/vdso/vgettimeofday.c')
-rw-r--r--arch/tile/kernel/vdso/vgettimeofday.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/tile/kernel/vdso/vgettimeofday.c b/arch/tile/kernel/vdso/vgettimeofday.c
new file mode 100644
index 0000000..51ec8e4
--- /dev/null
+++ b/arch/tile/kernel/vdso/vgettimeofday.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#define VDSO_BUILD /* avoid some shift warnings for -m32 in <asm/page.h> */
+#include <linux/time.h>
+#include <asm/timex.h>
+#include <asm/vdso.h>
+
+#if CHIP_HAS_SPLIT_CYCLE()
+static inline cycles_t get_cycles_inline(void)
+{
+ unsigned int high = __insn_mfspr(SPR_CYCLE_HIGH);
+ unsigned int low = __insn_mfspr(SPR_CYCLE_LOW);
+ unsigned int high2 = __insn_mfspr(SPR_CYCLE_HIGH);
+
+ while (unlikely(high != high2)) {
+ low = __insn_mfspr(SPR_CYCLE_LOW);
+ high = high2;
+ high2 = __insn_mfspr(SPR_CYCLE_HIGH);
+ }
+
+ return (((cycles_t)high) << 32) | low;
+}
+#define get_cycles get_cycles_inline
+#endif
+
+/*
+ * Find out the vDSO data page address in the process address space.
+ */
+inline unsigned long get_datapage(void)
+{
+ unsigned long ret;
+
+ /* vdso data page located in the 2nd vDSO page. */
+ asm volatile ("lnk %0" : "=r"(ret));
+ ret &= ~(PAGE_SIZE - 1);
+ ret += PAGE_SIZE;
+
+ return ret;
+}
+
+int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+ cycles_t cycles;
+ unsigned long count, sec, ns;
+ volatile struct vdso_data *vdso_data;
+
+ vdso_data = (struct vdso_data *)get_datapage();
+ /* The use of the timezone is obsolete, normally tz is NULL. */
+ if (unlikely(tz != NULL)) {
+ while (1) {
+ /* Spin until the update finish. */
+ count = vdso_data->tz_update_count;
+ if (count & 1)
+ continue;
+
+ tz->tz_minuteswest = vdso_data->tz_minuteswest;
+ tz->tz_dsttime = vdso_data->tz_dsttime;
+
+ /* Check whether updated, read again if so. */
+ if (count == vdso_data->tz_update_count)
+ break;
+ }
+ }
+
+ if (unlikely(tv == NULL))
+ return 0;
+
+ while (1) {
+ /* Spin until the update finish. */
+ count = vdso_data->tb_update_count;
+ if (count & 1)
+ continue;
+
+ cycles = (get_cycles() - vdso_data->xtime_tod_stamp);
+ ns = (cycles * vdso_data->mult) >> vdso_data->shift;
+ sec = vdso_data->xtime_clock_sec;
+ ns += vdso_data->xtime_clock_nsec;
+ if (ns >= NSEC_PER_SEC) {
+ ns -= NSEC_PER_SEC;
+ sec += 1;
+ }
+
+ /* Check whether updated, read again if so. */
+ if (count == vdso_data->tb_update_count)
+ break;
+ }
+
+ tv->tv_sec = sec;
+ tv->tv_usec = ns / 1000;
+
+ return 0;
+}
+
+int gettimeofday(struct timeval *tv, struct timezone *tz)
+ __attribute__((weak, alias("__vdso_gettimeofday")));