[PATCH v3 01/24] kernel: Standardize vdso_datapage

[Vincenzo Frascino <vincenzo.frascino@arm.com>]

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 */
-- 
2.19.2