linux_old1/arch/um
David Hildenbrand 70ffdb9393 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.

Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-19 08:39:15 +02:00
..
configs arch/um: make it work with defconfig and x86_64 2013-11-17 11:31:48 +01:00
drivers uml: Fix unsafe pid reference to foreground process group 2014-11-05 16:26:13 -08:00
include Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/misc 2015-04-15 13:53:55 -07:00
kernel mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler 2015-05-19 08:39:15 +02:00
os-Linux um: Move uml_postsetup in the init_thread stack 2015-04-13 21:17:44 +02:00
scripts um: Preinclude include/linux/kern_levels.h 2012-09-27 20:20:09 +02:00
.gitignore um: tell git to ignore generated files 2010-03-06 11:26:28 -08:00
Kconfig.char um: remove used STDIO_CONSOLE Kconfig param 2013-11-17 11:32:27 +01:00
Kconfig.common um: Skip futex_atomic_cmpxchg_inatomic() test 2015-01-04 14:20:26 +01:00
Kconfig.debug lib: consolidate DEBUG_STACK_USAGE option 2011-05-25 08:39:54 -07:00
Kconfig.net arch/um: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:38:04 -08:00
Kconfig.rest um: switch to use of drivers/Kconfig 2011-11-02 14:15:41 +01:00
Kconfig.um Merge tag 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2015-04-15 13:49:27 -07:00
Makefile kbuild: use relative path more to include Makefile 2015-04-02 16:42:08 +02:00
Makefile-os-Linux
Makefile-skas