[PATCH] [POWERPC] Use a sensible default for clock_getres() in the vdso.

Tony Breeds
2008-02-05T05:18:56Z

On Sun, Jan 27, 2008 at 07:32:59PM +0530, Sripathi Kodi wrote:
> Hi Paul,
>
> On PPC, I see a disparity between clock_getres implementations in the
> vdso and syscall. I am using a IBM Openpower hardware and 2.6.24 kernel
> with CONFIG_HIGH_RES_TIMERS=y.
>
> clock_getres call for CLOCK_REALTIME returns 1 millisecond. However,
> when I edit arch/powerpc/kernel/vdso*/gettimeofday.S to force it to use
> sys_clock_getres, I get 1 nanosecond resolution. The code in vdso seems
> to be returning some pre-defined (incorrect) variables.
>
> Could you please let me know the reason for this? Is it something that
> should be fixed in vdso?

Can you try the attached patch and see it if works for you?

From: Tony Breeds <tony@bakeyournoodle.com>
Subject: [PATCH] [POWERPC] Use a sensible default for clock_getres() in the vdso.

This ensures that the syscall and the (fast) vdso versions of clock_getres()
will return the same resolution.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
---
arch/powerpc/kernel/asm-offsets.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index ed083fe..e6e4928 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -22,6 +22,7 @@
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/suspend.h>
+#include <linux/hrtimer.h>
#ifdef CONFIG_PPC64
#include <linux/time.h>
#include <linux/hardirq.h>
@@ -312,7 +313,7 @@ int main(void)
DEFINE(CLOCK_REALTIME, CLOCK_REALTIME);
DEFINE(CLOCK_MONOTONIC, CLOCK_MONOTONIC);
DEFINE(NSEC_PER_SEC, NSEC_PER_SEC);
- DEFINE(CLOCK_REALTIME_RES, TICK_NSEC);
+ DEFINE(CLOCK_REALTIME_RES, (KTIME_MONOTONIC_RES).tv64);

#ifdef CONFIG_BUG
DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry));
--
1.5.4

Yours Tony

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