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* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* mm: do not pass mm_struct into handle_mm_faultKirill A. Shutemov2016-07-261-1/+1
| | | | | | | | | We always have vma->vm_mm around. Link: http://lkml.kernel.org/r/1466021202-61880-8-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ARC: mm: preps ahead of HIGHMEM supportVineet Gupta2015-10-281-3/+10
| | | | | | | | | | Before we plug in highmem support, some of code needs to be ready for it - copy_user_highpage() needs to be using the kmap_atomic API - mk_pte() can't assume page_address() - do_page_fault() can't assume VMALLOC_END is end of kernel vaddr space Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in ↵David Hildenbrand2015-05-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* ARC: perf: Enable generic software eventsVineet Gupta2015-02-271-2/+10
| | | | Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* arc: mm: Fix build failureGuenter Roeck2015-01-301-1/+1
| | | | | | | | Fix misspelled define. Fixes: 33692f27597f ("vm: add VM_FAULT_SIGSEGV handling support") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vm: add VM_FAULT_SIGSEGV handling supportLinus Torvalds2015-01-291-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The core VM already knows about VM_FAULT_SIGBUS, but cannot return a "you should SIGSEGV" error, because the SIGSEGV case was generally handled by the caller - usually the architecture fault handler. That results in lots of duplication - all the architecture fault handlers end up doing very similar "look up vma, check permissions, do retries etc" - but it generally works. However, there are cases where the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV. In particular, when accessing the stack guard page, libsigsegv expects a SIGSEGV. And it usually got one, because the stack growth is handled by that duplicated architecture fault handler. However, when the generic VM layer started propagating the error return from the stack expansion in commit fee7e49d4514 ("mm: propagate error from stack expansion even for guard page"), that now exposed the existing VM_FAULT_SIGBUS result to user space. And user space really expected SIGSEGV, not SIGBUS. To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those duplicate architecture fault handlers about it. They all already have the code to handle SIGSEGV, so it's about just tying that new return value to the existing code, but it's all a bit annoying. This is the mindless minimal patch to do this. A more extensive patch would be to try to gather up the mostly shared fault handling logic into one generic helper routine, and long-term we really should do that cleanup. Just from this patch, you can generally see that most architectures just copied (directly or indirectly) the old x86 way of doing things, but in the meantime that original x86 model has been improved to hold the VM semaphore for shorter times etc and to handle VM_FAULT_RETRY and other "newer" things, so it would be a good idea to bring all those improvements to the generic case and teach other architectures about them too. Reported-and-tested-by: Takashi Iwai <tiwai@suse.de> Tested-by: Jan Engelhardt <jengelh@inai.de> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots" Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, arc: remove obsolete pagefault oom killer commentDavid Rientjes2014-08-071-1/+0
| | | | | | | | | | Commit 609838cfed97 ("mm: invoke oom-killer from remaining unconverted page fault handlers") converted arc to call pagefault_out_of_memory(), so remove the comment about future conversion. Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: Change calling convention of do_page_fault()Vineet Gupta2013-11-061-1/+1
| | | | | | | | | | switch the args (address, pt_regs) to match with all the other "C" exception handlers. This removes the awkwardness in EV_ProtV for page fault vs. unaligned access. Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: Incorrect mm reference used in vmalloc fault handlerVineet Gupta2013-11-021-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | A vmalloc fault needs to sync up PGD/PTE entry from init_mm to current task's "active_mm". ARC vmalloc fault handler however was using mm. A vmalloc fault for non user task context (actually pre-userland, from init thread's open for /dev/console) caused the handler to deref NULL mm (for mm->pgd) The reasons it worked so far is amazing: 1. By default (!SMP), vmalloc fault handler uses a cached value of PGD. In SMP that MMU register is repurposed hence need for mm pointer deref. 2. In pre-3.12 SMP kernel, the problem triggering vmalloc didn't exist in pre-userland code path - it was introduced with commit 20bafb3d23d108bc "n_tty: Move buffers into n_tty_data" Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Gilad Ben-Yossef <gilad@benyossef.com> Cc: Noam Camus <noamc@ezchip.com> Cc: stable@vger.kernel.org #3.10 and 3.11 Cc: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* arch: mm: pass userspace fault flag to generic fault handlerJohannes Weiner2013-09-121-2/+4
| | | | | | | | | | | | | | | | | | | | 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 <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* arch: mm: remove obsolete init OOM protectionJohannes Weiner2013-09-121-5/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The memcg code can trap tasks in the context of the failing allocation until an OOM situation is resolved. They can hold all kinds of locks (fs, mm) at this point, which makes it prone to deadlocking. This series converts memcg OOM handling into a two step process that is started in the charge context, but any waiting is done after the fault stack is fully unwound. Patches 1-4 prepare architecture handlers to support the new memcg requirements, but in doing so they also remove old cruft and unify out-of-memory behavior across architectures. Patch 5 disables the memcg OOM handling for syscalls, readahead, kernel faults, because they can gracefully unwind the stack with -ENOMEM. OOM handling is restricted to user triggered faults that have no other option. Patch 6 reworks memcg's hierarchical OOM locking to make it a little more obvious wth is going on in there: reduce locked regions, rename locking functions, reorder and document. Patch 7 implements the two-part OOM handling such that tasks are never trapped with the full charge stack in an OOM situation. This patch: Back before smart OOM killing, when faulting tasks were killed directly on allocation failures, the arch-specific fault handlers needed special protection for the init process. Now that all fault handlers call into the generic OOM killer (see commit 609838cfed97: "mm: invoke oom-killer from remaining unconverted page fault handlers"), which already provides init protection, the arch-specific leftovers can be removed. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: invoke oom-killer from remaining unconverted page fault handlersJohannes Weiner2013-07-091-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | A few remaining architectures directly kill the page faulting task in an out of memory situation. This is usually not a good idea since that task might not even use a significant amount of memory and so may not be the optimal victim to resolve the situation. Since 2.6.29's 1c0fe6e ("mm: invoke oom-killer from page fault") there is a hook that architecture page fault handlers are supposed to call to invoke the OOM killer and let it pick the right task to kill. Convert the remaining architectures over to this hook. To have the previous behavior of simply taking out the faulting task the vm.oom_kill_allocating_task sysctl can be set to 1. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc bits] Cc: James Hogan <james.hogan@imgtec.com> Cc: David Howells <dhowells@redhat.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ARC: Remove explicit passing around of ECRVineet Gupta2013-06-261-7/+5
| | | | | | | | | | | | With ECR now part of pt_regs * No need to propagate from lowest asm handlers as arg * No need to save it in tsk->thread.cause_code * Avoid bit chopping to access the bit-fields More code consolidation, cleanup Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: [mm] Remove @write argument to do_page_fault()Vineet Gupta2013-06-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | This can be ascertained within do_page_fault() since it gets the full ECR (Exception Cause Register). Further, for both the callers of do_page_fault(): Prot-V / D-TLB-Miss, the cause sub-fields in ECR are same for same type of access, making the code much more simpler. D-TLB-Miss [LD] 0x00_21_01_00 Prot-V [LD] 0x00_23_01_00 ^^ D-TLB-Miss [ST] 0x00_21_02_00 Prot-V [ST] 0x00_23_02_00 ^^ D-TLB-Miss [EX] 0x00_21_03_00 Prot-V [EX] 0x00_23_03_00 ^^ This helps code consolidation, which is even better when moving code from assembler to "C". Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: Disintegrate arcregs.hVineet Gupta2013-06-221-0/+1
| | | | | | | | | * Move the various sub-system defines/types into relevant files/functions (reduces compilation time) * move CPU specific stuff out of asm/tlb.h into asm/mmu.h Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: Remove unneeded version.h header includeSachin Kamat2013-04-091-1/+0
| | | | | | | | version.h header file inclusion is not necessary as detected by versioncheck script. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
* ARC: Page Fault handlingVineet Gupta2013-02-151-0/+228
This includes recent changes to make handler "retry" and/or "killable" The killable (early exit) logic is loosely based on how SH implements it return if SIGKILL + either of VM_FAULT_OOM or VM_FAULT_RETRY which is different from Hexagon implementation which would NOT early exit for SIGKILL + VM_FAULT_OOM + !VM_FAULT_RETRY credits: Non executable stack support from Simon Spooner Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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