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 000000000000..51ec8e46f5f9
--- /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+	/* The use of the timezone is obsolete, normally tz is NULL.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")));