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

powerpc: Add plain English description for alignment exception oopses

2015-07-06T10:24:35+00:00

If we take an alignment exception which we cannot fix, the oops currently prints: Unable to handle kernel paging request for unknown fault Lets print something more useful: Unable to handle kernel paging request for unaligned access at address 0xc0000000f77bba8f Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman

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

ppc64: add paranoid warnings for unexpected DSISR_PROTFAULT

2015-02-13T02:54:08+00:00

ppc64 should not be depending on DSISR_PROTFAULT and it's unexpected if they are triggered. This patch adds warnings just in case they are being accidentally depended upon. Signed-off-by: Mel Gorman Acked-by: Aneesh Kumar K.V Tested-by: Sasha Levin Cc: Benjamin Herrenschmidt Cc: Dave Jones Cc: Hugh Dickins Cc: Ingo Molnar Cc: Kirill Shutemov Cc: Linus Torvalds Cc: Paul Mackerras Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: convert p[te|md]_numa users to p[te|md]_protnone_numa

2015-02-13T02:54:08+00:00

Convert existing users of pte_numa and friends to the new helper. Note that the kernel is broken after this patch is applied until the other page table modifiers are also altered. This patch layout is to make review easier. Signed-off-by: Mel Gorman Acked-by: Linus Torvalds Acked-by: Aneesh Kumar Acked-by: Benjamin Herrenschmidt Tested-by: Sasha Levin Cc: Dave Jones Cc: Hugh Dickins Cc: Ingo Molnar Cc: Kirill Shutemov Cc: Paul Mackerras Cc: Rik van Riel Cc: Sasha Levin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vm: add VM_FAULT_SIGSEGV handling support

2015-01-29T18:51:32+00:00

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 Tested-by: Jan Engelhardt Acked-by: Heiko Carstens # "s390 still compiles and boots" Cc: linux-arch@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds

powerpc/8xx: Invalidate non present TLB as early as possible

2014-11-08T00:10:45+00:00

8xx sometimes need to load a invalid/non-present TLBs in it DTLB asm handler. These must be invalidated separaly as linux mm doesn't. Commit 5efab4a02c89c252fb4cce097aafde5f8208dbfe was invalidating them in arch/powerpc/mm/fault.c. This patch does the invalidation earlier in order to free the TLB as soon as possible. This also has the advantage of removing some 8xx specific code from fault.c Signed-off-by: Christophe Leroy Signed-off-by: Scott Wood

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-10-13T14:23:15+00:00

Pull scheduler updates from Ingo Molnar: "The main changes in this cycle were: - Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave Hansen) - Various sched/idle refinements for better idle handling (Nicolas Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot) - sched/numa updates and optimizations (Rik van Riel) - sysbench speedup (Vincent Guittot) - capacity calculation cleanups/refactoring (Vincent Guittot) - Various cleanups to thread group iteration (Oleg Nesterov) - Double-rq-lock removal optimization and various refactorings (Kirill Tkhai) - various sched/deadline fixes ... and lots of other changes" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits) sched/dl: Use dl_bw_of() under rcu_read_lock_sched() sched/fair: Delete resched_cpu() from idle_balance() sched, time: Fix build error with 64 bit cputime_t on 32 bit systems sched: Improve sysbench performance by fixing spurious active migration sched/x86: Fix up typo in topology detection x86, sched: Add new topology for multi-NUMA-node CPUs sched/rt: Use resched_curr() in task_tick_rt() sched: Use rq->rd in sched_setaffinity() under RCU read lock sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask' sched: Use dl_bw_of() under RCU read lock sched/fair: Remove duplicate code from can_migrate_task() sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW sched: print_rq(): Don't use tasklist_lock sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock() sched: Fix the task-group check in tg_has_rt_tasks() sched/fair: Leverage the idle state info when choosing the "idlest" cpu sched: Let the scheduler see CPU idle states sched/deadline: Fix inter- exclusive cpusets migrations sched/deadline: Clear dl_entity params when setscheduling to different class sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault() ...

powerpc: Fill in si_addr_lsb siginfo field

2014-10-02T07:15:17+00:00

Fill in the si_addr_lsb siginfo field so the hwpoison code can pass to userspace the length of memory that has been corrupted. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman

powerpc: Add VM_FAULT_HWPOISON handling to powerpc page fault handler

2014-10-02T07:15:13+00:00

do_page_fault was missing knowledge of HWPOISON, and we would oops if userspace tried to access a poisoned page: kernel BUG at arch/powerpc/mm/fault.c:180! Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman

powerpc: Simplify do_sigbus

2014-10-02T07:15:09+00:00

Exit out early for a kernel fault, avoiding indenting of most of the function. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman