kernel.git/arch/mips/mm/fault.c, branch linux-3.2.y

vm: add VM_FAULT_SIGSEGV handling support

2015-02-20T00:49:40Z

commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream. 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 Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: - Adjust filenames, context - Drop arc, metag, nios2 and lustre changes - For sh, patch both 32-bit and 64-bit implementations to use goto bad_area - For s390, pass int_code and trans_exc_code as arguments to do_no_context() and do_sigsegv()] Signed-off-by: Ben Hutchings

perf: Remove the nmi parameter from the swevent and overflow interface

2011-07-01T09:06:35Z

The nmi parameter indicated if we could do wakeups from the current context, if not, we would set some state and self-IPI and let the resulting interrupt do the wakeup. For the various event classes: - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from the PMI-tail (ARM etc.) - tracepoint: nmi=0; since tracepoint could be from NMI context. - software: nmi=[0,1]; some, like the schedule thing cannot perform wakeups, and hence need 0. As one can see, there is very little nmi=1 usage, and the down-side of not using it is that on some platforms some software events can have a jiffy delay in wakeup (when arch_irq_work_raise isn't implemented). The up-side however is that we can remove the nmi parameter and save a bunch of conditionals in fast paths. Signed-off-by: Peter Zijlstra Cc: Michael Cree Cc: Will Deacon Cc: Deng-Cheng Zhu Cc: Anton Blanchard Cc: Eric B Munson Cc: Heiko Carstens Cc: Paul Mundt Cc: David S. Miller Cc: Frederic Weisbecker Cc: Jason Wessel Cc: Don Zickus Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org Signed-off-by: Ingo Molnar

MIPS: add support for software performance events

2010-10-29T18:08:48Z

Software events are required as part of the measurable stuff by the Linux performance counter subsystem. Here is the list of events added by this patch: PERF_COUNT_SW_PAGE_FAULTS PERF_COUNT_SW_PAGE_FAULTS_MIN PERF_COUNT_SW_PAGE_FAULTS_MAJ PERF_COUNT_SW_ALIGNMENT_FAULTS PERF_COUNT_SW_EMULATION_FAULTS Signed-off-by: Deng-Cheng Zhu To: linux-mips@linux-mips.org Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: mingo@elte.hu Cc: acme@redhat.com Cc: jamie.iles@picochip.com Acked-by: David Daney Reviewed-by: Matt Fleming Patchwork: https://patchwork.linux-mips.org/patch/1686/ Signed-off-by: Ralf Baechle

MIPS: kprobe: Add support.

2010-08-05T12:26:29Z

This patch is based on previous work by Sony and Himanshu Chauhan. I have done some cleanup and implemented JProbes and KRETPROBES. The KRETPROBES part is pretty much copied verbatim from powerpc. A possible future enhance might be to factor out the common code. Signed-off-by: David Daney Cc: Himanshu Chauhan To: linux-mips@linux-mips.org To: ananth@in.ibm.com, To: anil.s.keshavamurthy@intel.com To: davem@davemloft.net To: masami.hiramatsu.pt@hitachi.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/1525/ Patchwork: https://patchwork.linux-mips.org/patch/1530/ Signed-off-by: Ralf Baechle

MIPS: Remove unnecessary header file inclusion from fault.c.

2010-08-05T12:25:59Z

Signed-off-by: Ralf Baechle

MIPS: Implement Read Inhibit/eXecute Inhibit

2010-02-27T11:53:26Z

The SmartMIPS ASE specifies how Read Inhibit (RI) and eXecute Inhibit (XI) bits in the page tables work. The upper two bits of EntryLo{0,1} are RI and XI when the feature is enabled in the PageGrain register. SmartMIPS only covers 32-bit systems. Cavium Octeon+ extends this to 64-bit systems by continuing to place the RI and XI bits in the top of EntryLo even when EntryLo is 64-bits wide. Because we need to carry the RI and XI bits in the PTE, the layout of the PTE is changed. There is a two instruction overhead in the TLB refill hot path to get the EntryLo bits into the proper position. Also the TLB load exception has to probe the TLB to check if RI or XI caused the exception. Also of note is that the layout of the PTE bits is done at compile and runtime rather than statically. In the 32-bit case this allows for the same number of PFN bits as before the patch as the _PAGE_HUGE is not supported in 32-bit kernels (we have _PAGE_NO_EXEC and _PAGE_NO_READ instead of _PAGE_READ and _PAGE_HUGE). The patch is tested on Cavium Octeon+, but should also work on 32-bit systems with the Smart-MIPS ASE. Signed-off-by: David Daney To: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/952/ Patchwork: http://patchwork.linux-mips.org/patch/956/ Patchwork: http://patchwork.linux-mips.org/patch/962/ Signed-off-by: Ralf Baechle

MIPS: Don't corrupt page tables on vmalloc fault.

2009-09-17T18:07:52Z

The code after the vmalloc_fault: label in do_page_fault() modifies user page tables, this is not correct for 64-bit kernels. For 64-bit kernels we should go straight to the no_context handler skipping vmalloc_fault. Signed-off-by: David Daney Signed-off-by: Ralf Baechle

MIPS: Drop mmap_sem in pagefault oom path

2009-08-03T16:52:40Z

Fix the pagefault oom path which does not drop mm->mmap_sem. This was introduced by commit c7c1e3846bac1e4b8a8941f6a194812e28b0a519 Signed-off-by: Akinobu Mita Signed-off-by: Ralf Baechle

Move FAULT_FLAG_xyz into handle_mm_fault() callers

2009-06-21T20:08:22Z

This allows the callers to now pass down the full set of FAULT_FLAG_xyz flags to handle_mm_fault(). All callers have been (mechanically) converted to the new calling convention, there's almost certainly room for architectures to clean up their code and then add FAULT_FLAG_RETRY when that support is added. Signed-off-by: Linus Torvalds

MIPS: Port "mm: invoke oom-killer from page fault" from UML / x86

2009-01-30T21:32:57Z

Original commit 1c0fe6e3bda0464728c23c8d84aa47567e8b716c. Signed-off-by: Ralf Baechle