BMC/Intel-BMC/linux.git/arch/arm/mm/fault.c, branch dev

mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler

2015-05-19T06:39:15+00:00

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 Signed-off-by: David Hildenbrand Signed-off-by: Peter Zijlstra (Intel) Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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

ARM: dump pgd, pmd and pte states on unhandled data abort faults

2015-03-10T19:54:56+00:00

It can be useful to dump the page table entries when an unhandled data abort fault occurs. This can aid debugging of these situations, for example, a STREX instruction causing an external abort on non-linefetch fault, as has been reported recently. Signed-off-by: Russell King

ARM: convert printk(KERN_* to pr_*

2014-11-21T15:24:50+00:00

Convert many (but not all) printk(KERN_* to pr_* to simplify the code. We take the opportunity to join some printk lines together so we don't split the message across several lines, and we also add a few levels to some messages which were previously missing them. Tested-by: Andrew Lunn Tested-by: Felipe Balbi Signed-off-by: Russell King

arch: mm: pass userspace fault flag to generic fault handler

2013-09-12T22:38:01+00:00

Unlike global OOM handling, memory cgroup code will invoke the OOM killer in any OOM situation because it has no way of telling faults occuring in kernel context - which could be handled more gracefully - from user-triggered faults. Pass a flag that identifies faults originating in user space from the architecture-specific fault handlers to generic code so that memcg OOM handling can be improved. Signed-off-by: Johannes Weiner Reviewed-by: Michal Hocko Cc: David Rientjes Cc: KAMEZAWA Hiroyuki Cc: azurIt Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arch: mm: do not invoke OOM killer on kernel fault OOM

2013-09-12T22:38:01+00:00

Kernel faults are expected to handle OOM conditions gracefully (gup, uaccess etc.), so they should never invoke the OOM killer. Reserve this for faults triggered in user context when it is the only option. Most architectures already do this, fix up the remaining few. Signed-off-by: Johannes Weiner Reviewed-by: Michal Hocko Acked-by: KOSAKI Motohiro Cc: David Rientjes Cc: KAMEZAWA Hiroyuki Cc: azurIt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ARM: 7775/1: mm: Remove do_sect_fault from LPAE code

2013-06-29T10:23:23+00:00

For LPAE, do_sect_fault used to be invoked as the second level access flag handler. When transparent huge pages were introduced for LPAE, do_page_fault was used instead. Unfortunately, do_sect_fault remains defined but not used for LPAE code resulting in a compile warning. This patch surrounds do_sect_fault with #ifndef CONFIG_ARM_LPAE to fix this warning. Signed-off-by: Steve Capper Acked-by: Arnd Bergmann Signed-off-by: Russell King

readahead: fault retry breaks mmap file read random detection

2012-10-09T07:22:47+00:00

.fault now can retry. The retry can break state machine of .fault. In filemap_fault, if page is miss, ra->mmap_miss is increased. In the second try, since the page is in page cache now, ra->mmap_miss is decreased. And these are done in one fault, so we can't detect random mmap file access. Add a new flag to indicate .fault is tried once. In the second try, skip ra->mmap_miss decreasing. The filemap_fault state machine is ok with it. I only tested x86, didn't test other archs, but looks the change for other archs is obvious, but who knows :) Signed-off-by: Shaohua Li Cc: Rik van Riel Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'v3-removal' into for-linus

2012-05-21T14:15:33+00:00

Conflicts: arch/arm/boot/compressed/head.S

ARM: prevent VM_GROWSDOWN mmaps extending below FIRST_USER_ADDRESS

2012-05-16T14:20:59+00:00

Cc: Reported-by: Al Viro Signed-off-by: Russell King

ARM: Remove support for ARMv3 ARM610 and ARM710 CPUs

2012-05-05T04:50:50+00:00

This patch removes support for ARMv3 CPUs, which haven't worked properly for quite some time (see the FIXME comment in arch/arm/mm/fault.c). The only V3 parts left is the cache model for ARMv3, which is needed for some odd reason by ARM740T CPUs, and being able to build with -march=armv3, which is required for the RiscPC platform due to its bus structure. Acked-by: Will Deacon Acked-by: Jean-Christophe PLAGNIOL-VILLARD Signed-off-by: Russell King