lwn.git/arch/tile/mm/fault.c, branch standardize-docs

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:35+00:00

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to 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 Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:34+00:00

tile: migrate exception table users off module.h and onto extable.h

2016-12-16T20:32:29+00:00

These files were only including module.h for exception table related functions. We've now separated that content out into its own file "extable.h" so now move over to that and avoid all the extra header content in module.h that we don't really need to compile these files. Cc: Chris Metcalf Signed-off-by: Paul Gortmaker Signed-off-by: Chris Metcalf

mm: do not pass mm_struct into handle_mm_fault

2016-07-26T23:19:19+00:00

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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

arch/tile: move user_exit() to early kernel entry sequence

2016-01-18T19:49:30+00:00

This ensures that we always notify context tracking that we have exited from user space no matter how we enter the kernel. It is similar to how arm64 handles context tracking, for example. This allows the removal of all the exception_enter() calls that were added in commit 49e4e15619cd ("tile: support CONTEXT_TRACKING and thus NOHZ_FULL"). Signed-off-by: Chris Metcalf

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2015-07-01T04:47:12+00:00

Pull arch/tile updates from Chris Metcalf: "These are a grab bag of changes to improve debugging and respond to a variety of issues raised on LKML over the last couple of months" * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: tile: avoid a "label not used" warning in do_page_fault() tile: vdso: use raw_read_seqcount_begin() in vdso tile: force CONFIG_TILEGX if ARCH != tilepro tile: improve stack backtrace tile: fix "odd fault" warning for stack backtraces tile: set up initial stack top to honor STACK_TOP_DELTA tile: support delivering NMIs for multicore backtrace drivers/tty/hvc/hvc_tile.c: properly return -EAGAIN tile: add and enable support functions tile: use READ_ONCE() in arch_spin_is_locked() tile: modify arch_spin_unlock_wait() semantics

tile: avoid a "label not used" warning in do_page_fault()

2015-06-04T17:55:50+00:00

There are two different ifdef cases where the label is used, but if neither is true, the label is unused and the compiler generates a warning. Refactor the code the way x86 does so that there is a do_page_fault() that just does exception handling for context tracking, and make __do_page_fault() a static inline so that various cases can just return instead of doing a jump to "done". Signed-off-by: Chris Metcalf

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

tile: support CONTEXT_TRACKING and thus NOHZ_FULL

2015-04-17T18:01:10+00:00

Add the TIF_NOHZ flag appropriately. Add call to user_exit() on entry to do_work_pending() and on entry to syscalls via do_syscall_trace_enter(), and also the top of do_syscall_trace_exit() just because it's done in x86. Add call to user_enter() at the bottom of do_work_pending() once we have no more work to do before returning to userspace. Wrap all the trap code in exception_enter() / exception_exit(). Signed-off-by: Chris Metcalf Acked-by: Frederic Weisbecker

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