Thread (31 messages) 31 messages, 2 authors, 2019-01-15
STALE2694d
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[PATCH v4 01/24] kernel: Standardize vdso_datapage

From: Vincenzo Frascino <vincenzo.frascino@arm.com>
Date: 2019-01-15 13:56:33
Also in: linux-arch
Subsystem: generic vdso library, the rest · Maintainers: Andy Lutomirski, Thomas Gleixner, Vincenzo Frascino, Linus Torvalds

In an effort to unify the common code for managing the vdso library in
between all the architectures that support it, this patch tries to
provide a common format for the vdso datapage.

As a result of this, this patch generalized the data structures in vgtod.h
from x86 private includes to general includes (include/vdso).

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
 include/vdso/datapage.h | 60 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 include/vdso/datapage.h
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
new file mode 100644
index 000000000000..e88678f918e5
--- /dev/null
+++ b/include/vdso/datapage.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_DATAPAGE_H
+#define __VDSO_DATAPAGE_H
+
+#ifdef __KERNEL__
+
+#ifndef __ASSEMBLY__
+
+#include <linux/bits.h>
+#include <linux/types.h>
+#include <linux/time.h>
+
+#define VDSO_BASES	(CLOCK_TAI + 1)
+#define VDSO_HRES	(BIT(CLOCK_REALTIME)		| \
+			 BIT(CLOCK_MONOTONIC)		| \
+			 BIT(CLOCK_MONOTONIC_RAW)	| \
+			 BIT(CLOCK_BOOTTIME)		| \
+			 BIT(CLOCK_TAI))
+#define VDSO_COARSE	(BIT(CLOCK_REALTIME_COARSE)	| \
+			 BIT(CLOCK_MONOTONIC_COARSE))
+
+/*
+ * There is one vdso_timestamp object in vvar for each vDSO-accelerated
+ * clock_id. For high-resolution clocks, this encodes the time
+ * corresponding to vdso_data.cycle_last. For coarse clocks this encodes
+ * the actual time.
+ *
+ * To be noticed that nsec is left-shifted by vdso_data.shift.
+ */
+struct vdso_timestamp {
+	u64 sec;
+	u64 nsec;
+};
+
+/*
+ * vdso_data will be accessed by 32 and 64 bit code at the same time
+ * so we should be careful before modifying this structure.
+ */
+struct vdso_data {
+	u32 seq;		/* Timebase sequence counter */
+
+	s32 clock_mode;
+	u64 cycle_last;		/* Timebase at clocksource init */
+	u64 mask;		/* Clocksource mask (mono = raw) */
+	u32 mult;		/* Clocksource multiplier */
+	u32 shift;		/* Clocksource shift (mono = raw) */
+
+	struct vdso_timestamp basetime[VDSO_BASES];
+
+	s32 tz_minuteswest;	/* Timezone definitions */
+	s32 tz_dsttime;
+	u32 use_syscall;
+	u32 __reserved;
+};
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __KERNEL__ */
+
+#endif /* __VDSO_DATAPAGE_H */
-- 
2.20.1


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