diff options
| author | David Hildenbrand <dahi@linux.vnet.ibm.com> | 2015-05-11 17:52:11 +0200 |
|---|---|---|
| committer | Anders Roxell <anders.roxell@linaro.org> | 2015-07-26 11:07:12 +0200 |
| commit | 09d6d12faf9c8ef61a48f34efc7634a9c3a30faa (patch) | |
| tree | 479d46d59442c9d2e9c810e5ca221e81223cffc6 /arch/ia64 | |
| parent | ab2c5771d6c109d7a37c38619e0dfc599c31f1fe (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/ia64')
| -rw-r--r-- | arch/ia64/mm/fault.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index ba5ba7accd0d..70b40d1205a6 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -11,10 +11,10 @@ #include <linux/kprobes.h> #include <linux/kdebug.h> #include <linux/prefetch.h> +#include <linux/uaccess.h> #include <asm/pgtable.h> #include <asm/processor.h> -#include <asm/uaccess.h> extern int die(char *, struct pt_regs *, long); @@ -96,7 +96,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re /* * If we're in an interrupt or have no user context, we must not take the fault.. */ - if (in_atomic() || !mm) + if (faulthandler_disabled() || !mm) goto no_context; #ifdef CONFIG_VIRTUAL_MEM_MAP |