diff options
| author | David Hildenbrand <dahi@linux.vnet.ibm.com> | 2015-05-11 17:52:11 +0200 |
|---|---|---|
| committer | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2015-01-01 00:00:00 +0100 |
| commit | 41dc22b7f11e1325def5f4cdd307d106d64c67fb (patch) | |
| tree | 77fd87cb74051744d030185c61329f8774dfaebe /arch/m32r | |
| parent | 3a8a62ac527a74aa640e0e2d91732e39acbc1d3a (diff) | |
mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler
Introduce faulthandler_disabled() and use it to check for irq context and
disabled pagefaults (via pagefault_disable()) in the pagefault handlers.
Please note that we keep the in_atomic() checks in place - to detect
whether in irq context (in which case preemption is always properly
disabled).
In contrast, preempt_disable() should never be used to disable pagefaults.
With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt
counter, and therefore the result of in_atomic() differs.
We validate that condition by using might_fault() checks when calling
might_sleep().
Therefore, add a comment to faulthandler_disabled(), describing why this
is needed.
faulthandler_disabled() and pagefault_disable() are defined in
linux/uaccess.h, so let's properly add that include to all relevant files.
This patch is based on a patch from Thomas Gleixner.
[upstream commit 70ffdb9393a7264a069265edded729078dcf0425]
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Diffstat (limited to 'arch/m32r')
| -rw-r--r-- | arch/m32r/mm/fault.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/m32r/mm/fault.c b/arch/m32r/mm/fault.c index e3d4d4890104..8f9875b7933d 100644 --- a/arch/m32r/mm/fault.c +++ b/arch/m32r/mm/fault.c @@ -24,9 +24,9 @@ #include <linux/vt_kern.h> /* For unblank_screen() */ #include <linux/highmem.h> #include <linux/module.h> +#include <linux/uaccess.h> #include <asm/m32r.h> -#include <asm/uaccess.h> #include <asm/hardirq.h> #include <asm/mmu_context.h> #include <asm/tlbflush.h> @@ -111,10 +111,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, mm = tsk->mm; /* - * If we're in an interrupt or have no user context or are running in an - * atomic region then we must not take the fault.. + * If we're in an interrupt or have no user context or have pagefaults + * disabled then we must not take the fault. */ - if (in_atomic() || !mm) + if (faulthandler_disabled() || !mm) goto bad_area_nosemaphore; if (error_code & ACE_USERMODE) |