aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorAnton Blanchard <anton@samba.org>2012-09-03 16:47:56 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-12-17 10:49:05 -0800
commit1758e55fd05e042e873f6d54657552ee1730bb32 (patch)
treef38b64de33726999219a359869067db9b88b5482
parent7a09a2fff84eda4ac1bba98a61a61bd58f369bed (diff)
downloadkernel_samsung_smdk4412-1758e55fd05e042e873f6d54657552ee1730bb32.zip
kernel_samsung_smdk4412-1758e55fd05e042e873f6d54657552ee1730bb32.tar.gz
kernel_samsung_smdk4412-1758e55fd05e042e873f6d54657552ee1730bb32.tar.bz2
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>
-rw-r--r--arch/powerpc/kernel/sysfs.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/sysfs.c b/arch/powerpc/kernel/sysfs.c
index f0f2199..d62af95 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;
}