diff options
| author | Anton Blanchard <anton@samba.org> | 2012-09-03 16:47:56 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-12-17 10:49:05 -0800 |
| commit | 1758e55fd05e042e873f6d54657552ee1730bb32 (patch) | |
| tree | f38b64de33726999219a359869067db9b88b5482 /arch | |
| parent | 7a09a2fff84eda4ac1bba98a61a61bd58f369bed (diff) | |
powerpc: Update DSCR on all CPUs when writing sysfs dscr_default
commit 1b6ca2a6fe56e7697d57348646e07df08f43b1bb upstream.
Writing to dscr_default in sysfs doesn't actually change the DSCR -
we rely on a context switch on each CPU to do the work. There is no
guarantee we will get a context switch in a reasonable amount of time
so fire off an IPI to force an immediate change.
This issue was found with the following test case:
http://ozlabs.org/~anton/junkcode/dscr_explicit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kernel/sysfs.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c index f0f2199e64e..d62af950695 100644 --- a/arch/powerpc/kernel/sysfs.c +++ b/arch/powerpc/kernel/sysfs.c @@ -192,6 +192,12 @@ static ssize_t show_dscr_default(struct sysdev_class *class, return sprintf(buf, "%lx\n", dscr_default); } +static void update_dscr(void *dummy) +{ + if (!current->thread.dscr_inherit) + mtspr(SPRN_DSCR, dscr_default); +} + static ssize_t __used store_dscr_default(struct sysdev_class *class, struct sysdev_class_attribute *attr, const char *buf, size_t count) @@ -204,6 +210,8 @@ static ssize_t __used store_dscr_default(struct sysdev_class *class, return -EINVAL; dscr_default = val; + on_each_cpu(update_dscr, NULL, 1); + return count; } |