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authorAnton Blanchard <anton@samba.org>2012-09-03 16:47:56 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2012-09-05 16:05:20 +1000
commit1b6ca2a6fe56e7697d57348646e07df08f43b1bb (patch)
treee6002bbd58816dfe10b639e2843c804b5dad18c3 /arch/powerpc/kernel/sysfs.c
parent375f561a4131a0f501c8845a2a20f2ca1abc8f7a (diff)
downloadlinux-linaro-stable-1b6ca2a6fe56e7697d57348646e07df08f43b1bb.tar.gz
powerpc: Update DSCR on all CPUs when writing sysfs dscr_default
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> Cc: <stable@kernel.org> # 3.0+ Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/sysfs.c')
-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 3529446c2abd..d4cbbd1fa75f 100644
--- a/arch/powerpc/kernel/sysfs.c
+++ b/arch/powerpc/kernel/sysfs.c
@@ -194,6 +194,12 @@ static ssize_t show_dscr_default(struct device *dev,
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 device *dev,
struct device_attribute *attr, const char *buf,
size_t count)
@@ -206,6 +212,8 @@ static ssize_t __used store_dscr_default(struct device *dev,
return -EINVAL;
dscr_default = val;
+ on_each_cpu(update_dscr, NULL, 1);
+
return count;
}