commit: 1b6ca2a6fe56e7697d57348646e07df08f43b1bb From: Anton Blanchard <[email protected]> Date: Mon, 3 Sep 2012 16:47:56 +0000 Subject: 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 <[email protected]> Cc: <[email protected]> # 3.0+ Signed-off-by: Benjamin Herrenschmidt <[email protected]> --- 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 3529446..d4cbbd1 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; } -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
