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* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+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>
* mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in ↵David Hildenbrand2015-05-191-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* 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>
* arch: mm: pass userspace fault flag to generic fault handlerJohannes Weiner2013-09-121-3/+6
| | | | | | | | | | | | | | | | | | | | 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>
* mm, oom: remove statically defined arch functions of same nameDavid Rientjes2012-12-121-12/+7
| | | | | | | | | | | | | | | | | | | out_of_memory() is a globally defined function to call the oom killer. x86, sh, and powerpc all use a function of the same name within file scope in their respective fault.c unnecessarily. Inline the functions into the pagefault handlers to clean the code up. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* readahead: fault retry breaks mmap file read random detectionShaohua Li2012-10-091-0/+1
| | | | | | | | | | | | | | | | | | | .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 <shaohua.li@fusionio.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sh: Fix up recursive fault in oops with unset TTB.Paul Mundt2012-07-251-2/+6
| | | | | | | | | | | Presently the oops code looks for the pgd either from the mm context or the cached TTB value. There are presently cases where the TTB can be unset or otherwise cleared by hardware, which we weren't handling, resulting in recursive faults on the NULL pgd. In these cases we can simply reload from swapper_pg_dir and continue on as normal. Cc: stable@vger.kernel.org Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh64: Fix up vmalloc fault range check.Paul Mundt2012-05-181-1/+7
| | | | | | | | With the previous attempt reverted this switches to conditionalizing the end address. Nominally VMALLOC_END, but extended for P3_ADDR_MAX in the store queue case. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* Revert "sh: Ensure fixmap and store queue space can co-exist."Paul Mundt2012-05-181-2/+2
| | | | | | | | | This reverts commit 20e7c297efeca0861adcca073a0d283da659834b. With store queues enabled the area above P4SEG has special properties from the MMU's point of view, which was causing fixmap failure. We'll have to do something else to satisfy the vmalloc range check. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Enable shared page fault handler for _32/_64.Paul Mundt2012-05-141-0/+508
| | | | | | | This moves the now generic _32 page fault handling code to a shared place and adapts the _64 implementation to make use of it. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Move in the SH-5 TLB miss.Paul Mundt2008-01-281-303/+0
| | | | Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: lockless UTLB miss fast-path.Paul Mundt2007-11-191-18/+7
| | | | | | | | | | | | With the refactored update_mmu_cache() introduced in older kernels, there's no longer any need to take the page_table_lock in this path, so simply drop it completely. Without this, performance degradation is seen on SMP on heavily threaded workloads that don't use the split ptlock, and ultimately we have no reason to contend for the lock in the first place. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Kill off UTLB flush in fast-path.Paul Mundt2007-11-191-8/+0
| | | | | | | | | | | The __do_page_fault() fast-path contains a UTLB flush in order to force an ITLB reload, this isn't needed in practice as the ITLB is auto-reloaded from the UTLB anyways, which is already displaced by the manual 'ldtlb' in the update_mmu_cache() path. This provides a measurable speed up in the TLB miss fast-path. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* pid namespaces: define is_global_init() and is_container_init()Serge E. Hallyn2007-10-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | is_init() is an ambiguous name for the pid==1 check. Split it into is_global_init() and is_container_init(). A cgroup init has it's tsk->pid == 1. A global init also has it's tsk->pid == 1 and it's active pid namespace is the init_pid_ns. But rather than check the active pid namespace, compare the task structure with 'init_pid_ns.child_reaper', which is initialized during boot to the /sbin/init process and never changes. Changelog: 2.6.22-rc4-mm2-pidns1: - Use 'init_pid_ns.child_reaper' to determine if a given task is the global init (/sbin/init) process. This would improve performance and remove dependence on the task_pid(). 2.6.21-mm2-pidns2: - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc, ppc,avr32}/traps.c for the _exception() call to is_global_init(). This way, we kill only the cgroup if the cgroup's init has a bug rather than force a kernel panic. [akpm@linux-foundation.org: fix comment] [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c] [bunk@stusta.de: kernel/pid.c: remove unused exports] [sukadev@us.ibm.com: Fix capability.c to work with threaded init] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Acked-by: Pavel Emelianov <xemul@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Herbert Poetzel <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* During VM oom condition, kill all threads in process groupWill Schmidt2007-10-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have had complaints where a threaded application is left in a bad state after one of it's threads is killed when we hit a VM: out_of_memory condition. Killing just one of the process threads can leave the application in a bad state, whereas killing the entire process group would allow for the application to restart, or be otherwise handled, and makes it very obvious that something has gone wrong. This change allows the entire process group to be taken down, rather than just the one thread. Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Matthew Wilcox <willy@debian.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sh: Fix pgd mismatch from cached TTB in unhandled fault.Paul Mundt2007-08-011-2/+1
| | | | | | | | | | | When reading the cached TTB value and extracting the pgd, we accidentally applied a __va() to it and bumped it off in to bogus space which ended up causing multiple faults in the error path. Fix it up so unhandled faults don't do strange and highly unorthodox things when oopsing. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* mm: fault feedback #2Nick Piggin2007-07-191-12/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch completes Linus's wish that the fault return codes be made into bit flags, which I agree makes everything nicer. This requires requires all handle_mm_fault callers to be modified (possibly the modifications should go further and do things like fault accounting in handle_mm_fault -- however that would be for another patch). [akpm@linux-foundation.org: fix alpha build] [akpm@linux-foundation.org: fix s390 build] [akpm@linux-foundation.org: fix sparc build] [akpm@linux-foundation.org: fix sparc64 build] [akpm@linux-foundation.org: fix ia64 build] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Matthew Wilcox <willy@debian.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> [ Still apparently needs some ARM and PPC loving - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sh: Check oops_may_print() in unhandled fault.Paul Mundt2007-06-181-16/+29
| | | | | | | Only print out pgd/pte data in the oops path if oops_may_print() holds true. Follows the i386 implementation. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: revert addition of page fault notifiersChristoph Hellwig2007-05-211-37/+0
| | | | | | | | | | | | Just at the time you added them on sh we're removing them from other architectures. As there's no user yet this patch just removes them completely. Once you actually have a kprobes patch it should follow the direct call to kprobes_fault_handler model that powerpc, s390 and sparc64 employ in 2.6.22-rc1 and that I'm updating other architectures to. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Shut up compiler warnings in __do_page_fault().Paul Mundt2007-05-141-1/+1
| | | | | | | | | | | GCC doesn't seem to be able to figure this one out for itself, so just shut it up.. CC arch/sh/mm/fault.o arch/sh/mm/fault.c: In function '__do_page_fault': arch/sh/mm/fault.c:288: warning: 'ptl' may be used uninitialized in this function Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Convert to common die chain.Paul Mundt2007-05-091-1/+1
| | | | | | | This went in immediately after SH added the die chain notifiers, so move over to that instead.. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Add die chain notifiers.Paul Mundt2007-05-071-2/+37
| | | | | | Add the atomic die chains in, kprobes needs these. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Revert TLB miss fast-path changes that broke PTEA parts.Paul Mundt2007-02-141-0/+87
| | | | | | | | This ended up causing problems for older parts (particularly ones using PTEA). Revert this for now, it can be added back in once it's had some more testing. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: stacktrace/lockdep/irqflags tracing support.Paul Mundt2006-12-061-0/+3
| | | | | | Wire up all of the essentials for lockdep.. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Get the PGD right in oops case with 64-bit PTEs.Paul Mundt2006-12-061-4/+2
| | | | | | | | | | | | Previously this was using a static pgd shift in the reporting code, simply flip this to PGDIR_SHIFT which does the right thing depending on varying PTE magnitudes on the SH-X2 MMU. While we're at it, and since it's been recently added, use get_TTB() for fetching the TTB, rather than the open coded instructions. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: TLB miss fast-path optimizations.Stuart Menefy2006-12-061-86/+0
| | | | | | | | Handle simple TLB miss faults which can be resolved completely from the page table in assembler. Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: pmd rework.Stuart Menefy2006-12-061-0/+40
| | | | | | | | | Remove extra bits from the pmd structure and store a kernel logical address rather than a physical address. This allows it to be directly dereferenced. Another piece of wierdness inherited from x86. Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Set up correct siginfo structures for page faults.Stuart Menefy2006-12-061-9/+17
| | | | | | | | Remove the previous saving of fault codes into the thread_struct as they are never used, and appeared to be inherited from x86. Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* [PATCH] pidspace: is_init()Sukadev Bhattiprolu2006-09-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is an updated version of Eric Biederman's is_init() patch. (http://lkml.org/lkml/2006/2/6/280). It applies cleanly to 2.6.18-rc3 and replaces a few more instances of ->pid == 1 with is_init(). Further, is_init() checks pid and thus removes dependency on Eric's other patches for now. Eric's original description: There are a lot of places in the kernel where we test for init because we give it special properties. Most significantly init must not die. This results in code all over the kernel test ->pid == 1. Introduce is_init to capture this case. With multiple pid spaces for all of the cases affected we are looking for only the first process on the system, not some other process that has pid == 1. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: <lxc-devel@lists.sourceforge.net> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make PROT_WRITE imply PROT_READJason Baron2006-09-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make PROT_WRITE imply PROT_READ for a number of architectures which don't support write only in hardware. While looking at this, I noticed that some architectures which do not support write only mappings already take the exact same approach. For example, in arch/alpha/mm/fault.c: " if (cause < 0) { if (!(vma->vm_flags & VM_EXEC)) goto bad_area; } else if (!cause) { /* Allow reads even for write-only mappings */ if (!(vma->vm_flags & (VM_READ | VM_WRITE))) goto bad_area; } else { if (!(vma->vm_flags & VM_WRITE)) goto bad_area; } " Thus, this patch brings other architectures which do not support write only mappings in-line and consistent with the rest. I've verified the patch on ia64, x86_64 and x86. Additional discussion: Several architectures, including x86, can not support write-only mappings. The pte for x86 reserves a single bit for protection and its two states are read only or read/write. Thus, write only is not supported in h/w. Currently, if i 'mmap' a page write-only, the first read attempt on that page creates a page fault and will SEGV. That check is enforced in arch/blah/mm/fault.c. However, if i first write that page it will fault in and the pte will be set to read/write. Thus, any subsequent reads to the page will succeed. It is this inconsistency in behavior that this patch is attempting to address. Furthermore, if the page is swapped out, and then brought back the first read will also cause a SEGV. Thus, any arbitrary read on a page can potentially result in a SEGV. According to the SuSv3 spec, "if the application requests only PROT_WRITE, the implementation may also allow read access." Also as mentioned, some archtectures, such as alpha, shown above already take the approach that i am suggesting. The counter-argument to this raised by Arjan, is that the kernel is enforcing the write only mapping the best it can given the h/w limitations. This is true, however Alan Cox, and myself would argue that the inconsitency in behavior, that is applications can sometimes work/sometimes fails is highly undesireable. If you read through the thread, i think people, came to an agreement on the last patch i posted, as nobody has objected to it... Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Andi Kleen <ak@muc.de> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* sh: More cosmetic cleanups and trivial fixes.Paul Mundt2006-09-271-5/+8
| | | | | | Nothing exciting here, just trivial fixes.. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Fix split ptlock for user mappings in __do_page_fault().Paul Mundt2006-09-271-3/+4
| | | | | | | | There was a bug that got introduced when the split ptlock changes went in where mm could be unintialized for user mappings, this fixes it up.. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: page table alloc cleanups and page fault optimizations.Paul Mundt2006-09-271-162/+40
| | | | | | | | | | | Cleanup of page table allocators, using generic folded PMD and PUD helpers. TLB flushing operations are moved to a more sensible spot. The page fault handler is also optimized slightly, we no longer waste cycles on IRQ disabling for flushing of the page from the ITLB, since we're already under CLI protection by the initial exception handler. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* sh: Add control register barriers.Paul Mundt2006-09-271-2/+3
| | | | | | | | | | | | | | | | | | | | | | | Currently when making changes to control registers, we typically need some time for changes to take effect (8 nops, generally). However, for sh4a we simply need to do an icbi.. This is a simple patch for implementing a general purpose ctrl_barrier() which functions as a control register write barrier. There's some additional documentation in the patch itself, but it's pretty self explanatory. There were also some places where we were not doing the barrier, which didn't seem to have any adverse effects on legacy parts, but certainly did on sh4a. It's safer to have the barrier in place for legacy parts as well in these cases, though this does make flush_tlb_all() more expensive (by an order of 8 nops). We can ifdef around the flush_tlb_all() case for now if it's clear that all legacy parts won't have a problem with this. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* [PATCH] mm: i386 sh sh64 ready for split ptlockHugh Dickins2005-10-291-17/+23
| | | | | | | | | | | | | | | | | | | | | Use pte_offset_map_lock, instead of pte_offset_map (or inappropriate pte_offset_kernel) and mm-wide page_table_lock, in sundry arch places. The i386 vm86 mark_screen_rdonly: yes, there was and is an assumption that the screen fits inside the one page table, as indeed it does. The sh __do_page_fault: which handles both kernel faults (without lock) and user mm faults (locked - though it set_pte without locking before). The sh64 flush_cache_range and helpers: which wrongly thought callers held page_table_lock before (only its tlb_start_vma did, and no longer does so); moved the flush loop down, and adjusted the large versus small range decision to consider a range which spans page tables as large. Signed-off-by: Hugh Dickins <hugh@veritas.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+374
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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