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| author | Anton Blanchard <anton@samba.org> | 2012-09-03 16:47:56 +0000 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-09-19 15:04:40 +0100 |
| commit | b32fef3b4df0e254fb4d0fd3122a2668a5f11581 (patch) | |
| tree | f2b4c3f7e112247c8db01a93d37cebce4af4893b | |
| parent | 3b75588b26cc22a16ff812e38ba7720b3e2d9b38 (diff) | |
| download | kernel_samsung_smdk4412-b32fef3b4df0e254fb4d0fd3122a2668a5f11581.zip kernel_samsung_smdk4412-b32fef3b4df0e254fb4d0fd3122a2668a5f11581.tar.gz kernel_samsung_smdk4412-b32fef3b4df0e254fb4d0fd3122a2668a5f11581.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>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -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 ce035c1..0c3f949 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; } |