From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>, Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paul.burton@mips.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mark Salyzyn <salyzyn@android.com>,
Peter Collingbourne <pcc@google.com>,
Shuah Khan <shuah@kernel.org>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Huw Davies <huw@codeweavers.com>
Subject: [PATCH v6 01/19] kernel: Standardize vdso_datapage
Date: Thu, 30 May 2019 15:15:13 +0100 [thread overview]
Message-ID: <20190530141531.43462-2-vincenzo.frascino@arm.com> (raw)
In-Reply-To: <20190530141531.43462-1-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 | 91 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 91 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..bb7087eec9bd
--- /dev/null
+++ b/include/vdso/datapage.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_DATAPAGE_H
+#define __VDSO_DATAPAGE_H
+
+#ifdef __KERNEL__
+
+#ifndef __ASSEMBLY__
+
+#include <linux/bits.h>
+#include <linux/time.h>
+#include <linux/types.h>
+
+#define VDSO_BASES (CLOCK_TAI + 1)
+#define VDSO_HRES (BIT(CLOCK_REALTIME) | \
+ BIT(CLOCK_MONOTONIC) | \
+ BIT(CLOCK_BOOTTIME) | \
+ BIT(CLOCK_TAI))
+#define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \
+ BIT(CLOCK_MONOTONIC_COARSE))
+#define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW))
+
+#define CS_HRES_COARSE 0
+#define CS_RAW 1
+#define CS_BASES (CS_RAW + 1)
+
+/**
+ * struct vdso_timestamp - basetime per clock_id
+ * @sec: seconds
+ * @nsec: nanoseconds
+ *
+ * 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 for highres clocks nsec is left-shifted by
+ * vdso_data.cs[x].shift.
+ */
+struct vdso_timestamp {
+ u64 sec;
+ u64 nsec;
+};
+
+/**
+ * struct vdso_data - vdso datapage representation
+ * @seq: timebase sequence counter
+ * @clock_mode: clock mode
+ * @cycle_last: timebase at clocksource init
+ * @mask: clocksource mask
+ * @mult: clocksource multiplier
+ * @shift: clocksource shift
+ * @basetime[clock_id]: basetime per clock_id
+ * @tz_minuteswest: minutes west of Greenwich
+ * @tz_dsttime: type of DST correction
+ * @hrtimer_res: hrtimer resolution
+ *
+ * vdso_data will be accessed by 64 bit and compat code at the same time
+ * so we should be careful before modifying this structure.
+ */
+struct vdso_data {
+ u32 seq;
+
+ s32 clock_mode;
+ u64 cycle_last;
+ u64 mask;
+ u32 mult;
+ u32 shift;
+
+ struct vdso_timestamp basetime[VDSO_BASES];
+
+ s32 tz_minuteswest;
+ s32 tz_dsttime;
+ u32 hrtimer_res;
+};
+
+/*
+ * We use the hidden visibility to prevent the compiler from generating a GOT
+ * relocation. Not only is going through a GOT useless (the entry couldn't and
+ * must not be overridden by another library), it does not even work: the linker
+ * cannot generate an absolute address to the data page.
+ *
+ * With the hidden visibility, the compiler simply generates a PC-relative
+ * relocation, and this is what we need.
+ */
+extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __KERNEL__ */
+
+#endif /* __VDSO_DATAPAGE_H */
--
2.21.0
next prev parent reply other threads:[~2019-05-30 14:17 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 14:15 [PATCH v6 00/19] Unify vDSOs across more architectures Vincenzo Frascino
2019-05-30 14:15 ` Vincenzo Frascino [this message]
2019-05-31 8:16 ` [PATCH v6 01/19] kernel: Standardize vdso_datapage Arnd Bergmann
2019-06-04 12:05 ` Vincenzo Frascino
2019-06-10 17:47 ` Huw Davies
2019-06-10 9:27 ` Huw Davies
2019-06-10 10:17 ` Vincenzo Frascino
2019-06-10 10:31 ` Huw Davies
2019-06-10 11:07 ` Vincenzo Frascino
2019-06-10 11:37 ` Huw Davies
2019-05-30 14:15 ` [PATCH v6 02/19] kernel: Define gettimeofday vdso common code Vincenzo Frascino
2019-05-31 8:19 ` Arnd Bergmann
2019-06-04 12:08 ` Vincenzo Frascino
2019-06-10 9:31 ` Huw Davies
2019-06-10 10:18 ` Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 03/19] kernel: Unify update_vsyscall implementation Vincenzo Frascino
2019-06-10 9:34 ` Huw Davies
2019-06-10 10:19 ` Vincenzo Frascino
2019-06-14 11:10 ` Thomas Gleixner
2019-06-14 12:15 ` Vincenzo Frascino
2019-06-14 12:19 ` Thomas Gleixner
2019-06-14 12:25 ` Vincenzo Frascino
2019-06-14 13:07 ` Thomas Gleixner
2019-05-30 14:15 ` [PATCH v6 04/19] arm64: Substitute gettimeofday with C implementation Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 05/19] arm64: Build vDSO with -ffixed-x18 Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 06/19] arm64: compat: Add missing syscall numbers Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 07/19] arm64: compat: Expose signal related structures Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 08/19] arm64: compat: Generate asm offsets for signals Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 09/19] lib: vdso: Add compat support Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 10/19] arm64: compat: Add vDSO Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 11/19] arm64: Refactor vDSO code Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 12/19] arm64: compat: vDSO setup for compat layer Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 13/19] arm64: elf: vDSO code page discovery Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 14/19] arm64: compat: Get sigreturn trampolines from vDSO Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 15/19] arm64: Add vDSO compat support Vincenzo Frascino
2019-06-01 9:38 ` Catalin Marinas
2019-06-04 12:10 ` Vincenzo Frascino
2019-05-30 14:15 ` [PATCH v6 16/19] arm: Add support for generic vDSO Vincenzo Frascino
2019-05-31 8:32 ` Arnd Bergmann
2019-05-30 14:15 ` [PATCH v6 17/19] mips: " Vincenzo Frascino
2019-05-31 8:34 ` Arnd Bergmann
2019-06-03 14:54 ` Mark Salyzyn
2019-06-03 17:07 ` Arnd Bergmann
2019-05-30 14:15 ` [PATCH v6 18/19] x86: " Vincenzo Frascino
2019-05-30 15:41 ` Michael Kelley
2019-06-04 12:13 ` Vincenzo Frascino
2019-06-14 11:15 ` Thomas Gleixner
2019-06-14 21:17 ` Sasha Levin
2019-06-22 14:46 ` Thomas Gleixner
2019-06-23 19:09 ` Sasha Levin
2019-06-23 21:58 ` Stephen Rothwell
2019-06-24 0:24 ` Sasha Levin
2019-06-24 1:20 ` Stephen Rothwell
2019-06-23 22:12 ` Thomas Gleixner
2019-06-24 0:04 ` Michael Kelley
2019-06-24 0:25 ` Thomas Gleixner
2019-06-28 18:40 ` Michael Kelley
2019-05-30 14:15 ` [PATCH v6 19/19] kselftest: Extend vDSO selftest Vincenzo Frascino
2019-05-31 8:53 ` Arnd Bergmann
2019-05-31 8:46 ` [PATCH v6 00/19] Unify vDSOs across more architectures Arnd Bergmann
2019-06-04 12:04 ` Vincenzo Frascino
2019-06-04 12:12 ` Arnd Bergmann
2019-06-05 14:32 ` Vincenzo Frascino
2019-06-14 12:16 ` Thomas Gleixner
2019-06-14 12:19 ` Vincenzo Frascino
2019-06-20 6:17 ` Shijith Thotton
2019-06-20 8:55 ` Vincenzo Frascino
2019-06-20 16:27 ` Andre Przywara
2019-06-21 9:11 ` Vincenzo Frascino
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