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2012-04-25arch/tile: fix a couple of functions that should be __initChris Metcalf
They were marked __devinit by mistake, causing some warnings at link time. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-20VM: add "vm_mmap()" helper functionLinus Torvalds
This continues the theme started with vm_brk() and vm_munmap(): vm_mmap() does the same thing as do_mmap(), but additionally does the required VM locking. This uninlines (and rewrites it to be clearer) do_mmap(), which sadly duplicates it in mm/mmap.c and mm/nommu.c. But that way we don't have to export our internal do_mmap_pgoff() function. Some day we hopefully don't have to export do_mmap() either, if all modular users can become the simpler vm_mmap() instead. We're actually very close to that already, with the notable exception of the (broken) use in i810, and a couple of stragglers in binfmt_elf. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-11arch/tile: avoid unused variable warning in proc.c for tilegxChris Metcalf
Until we push the unaligned access support for tilegx, it's silly to have arch/tile/kernel/proc.c generate a warning about an unused variable. Extend the #ifdef to cover all the code and data for now. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-09tile/CPU hotplug: Add missing call to notify_cpu_starting()Srivatsa S. Bhat
The scheduler depends on receiving the CPU_STARTING notification, without which we end up into a lot of trouble. So add the missing call to notify_cpu_starting() in the bringup code. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-06Merge branch 'stable' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile Pull arch/tile bug fixes from Chris Metcalf: "This includes Paul Gortmaker's change to fix the <asm/system.h> disintegration issues on tile, a fix to unbreak the tilepro ethernet driver, and a backlog of bugfix-only changes from internal Tilera development over the last few months. They have all been to LKML and on linux-next for the last few days. The EDAC change to MAINTAINERS is an oddity but discussion on the linux-edac list suggested I ask you to pull that change through my tree since they don't have a tree to pull edac changes from at the moment." * 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (39 commits) drivers/net/ethernet/tile: fix netdev_alloc_skb() bombing MAINTAINERS: update EDAC information tilepro ethernet driver: fix a few minor issues tile-srom.c driver: minor code cleanup edac: say "TILEGx" not "TILEPro" for the tilegx edac driver arch/tile: avoid accidentally unmasking NMI-type interrupt accidentally arch/tile: remove bogus performance optimization arch/tile: return SIGBUS for addresses that are unaligned AND invalid arch/tile: fix finv_buffer_remote() for tilegx arch/tile: use atomic exchange in arch_write_unlock() arch/tile: stop mentioning the "kvm" subdirectory arch/tile: export the page_home() function. arch/tile: fix pointer cast in cacheflush.c arch/tile: fix single-stepping over swint1 instructions on tilegx arch/tile: implement panic_smp_self_stop() arch/tile: add "nop" after "nap" to help GX idle power draw arch/tile: use proper memparse() for "maxmem" options arch/tile: fix up locking in pgtable.c slightly arch/tile: don't leak kernel memory when we unload modules arch/tile: fix bug in delay_backoff() ...
2012-04-02arch/tile: avoid accidentally unmasking NMI-type interrupt accidentallyChris Metcalf
The return path as we reload registers and core state requires that r30 hold a boolean indicating whether we are returning from an NMI, but in a couple of cases we weren't setting this properly, with the result that we could accidentally unmask the NMI interrupt(s), which could cause confusion. Now we set r30 in every place where we jump into the interrupt return path. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: remove bogus performance optimizationChris Metcalf
We were re-homing the initial task's kernel stack on the boot cpu, but in fact it's better to let it stay globally homed, since that task isn't bound to the boot cpu anyway. This is more of a general cleanup than an actual performance optimization, but it removes code, which is a good thing. :-) Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: return SIGBUS for addresses that are unaligned AND invalidChris Metcalf
Previously we were returning SIGSEGV in this case. It seems cleaner to return SIGBUS since the hardware figures out alignment traps before TLB violations, so SIGBUS is the "more correct" signal. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix finv_buffer_remote() for tilegxChris Metcalf
There were some correctness issues with this code that are now fixed with this change. The change is likely less performant than it could be, but it should no longer be vulnerable to any races with memory operations on the memory network while invalidating a range of memory. This code is run infrequently so performance isn't critical, but correctness definitely is. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: use atomic exchange in arch_write_unlock()Chris Metcalf
This idiom is used elsewhere when we do an unlock by writing a zero, but I missed it here. Using an atomic operation avoids waiting on the write buffer for the unlocking write to be sent to the home cache. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: stop mentioning the "kvm" subdirectoryChris Metcalf
It causes "make clean" to fail, for example. Once we have KVM support complete, we'll reinstate the subdir reference. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: export the page_home() function.Chris Metcalf
This avois a bug in modules trying to use the function. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix pointer cast in cacheflush.cChris Metcalf
Pragmatically it couldn't be wrong to cast pointers to long to compare them (since all kernel addresses are in the top half of VA space), but it's more correct to cast to unsigned long. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix single-stepping over swint1 instructions on tilegxChris Metcalf
If we are single-stepping and make a syscall, we call ptrace_notify() explicitly on the return path back to user space, since we are returning to a pc value set artificially to the next instruction, and otherwise we won't register that we stepped over the syscall instruction (swint1). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: implement panic_smp_self_stop()Chris Metcalf
This allows the later-panicking tiles to wait in a lower power state until they get interrupted with an smp_send_stop(). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: add "nop" after "nap" to help GX idle power drawChris Metcalf
This avoids the hardware istream prefetcher doing unnecessary work. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: use proper memparse() for "maxmem" optionsChris Metcalf
This is more standard and avoids having to remember what units the options actually take. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix up locking in pgtable.c slightlyChris Metcalf
We should be holding the init_mm.page_table_lock in shatter_huge_page() since we are modifying the kernel page tables. Then, only if we are walking the other root page tables to update them, do we want to take the pgd_lock. Add a comment about taking the pgd_lock that we always do it with interrupts disabled and therefore are not at risk from the tlbflush IPI deadlock as is seen on x86. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: don't leak kernel memory when we unload modulesChris Metcalf
We were failing to track the memory when we allocated it. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix bug in delay_backoff()Chris Metcalf
We were carefully computing a value to use for the number of loops to spin for, and then ignoring it. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix bug in loading kernels larger than 16 MBChris Metcalf
Previously we only handled kernels up to a single huge page in size. Now we create additional PTEs appropriately. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: don't enable irqs unconditionally in page fault handlerChris Metcalf
If we took a page fault while we had interrupts disabled, we shouldn't enable them in the page fault handler. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: don't set the homecache of a PTE unless appropriateChris Metcalf
We make sure not to try to set the home for an MMIO PTE (on tilegx) or a PTE that isn't referencing memory managed by Linux. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: don't wait for migrating PTEs in an NMI handlerChris Metcalf
Doing so raises the possibility of self-deadlock if we are waiting for a backtrace for an oprofile or perf interrupt while we are in the middle of migrating our own stack page. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile/Makefile: use KCFLAGS when figuring out the libgcc path.Chris Metcalf
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix a couple of comments that needed updatingChris Metcalf
Not associated with any code changes, so I'm just lumping these comment changes into a commit by themselves. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix up some minor trap handling issuesChris Metcalf
We now respond to MEM_ERROR traps (e.g. an atomic instruction to non-cacheable memory) with a SIGBUS. We also no longer generate a console crash message if a user process die due to a SIGTRAP. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: work around a hardware issue with the return-address stackChris Metcalf
In certain circumstances we need to do a bunch of jump-and-link instructions to fill the hardware return-address stack with nonzero values. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: various bugs in stack backtracerChris Metcalf
Fix a long-standing bug in the stack backtracer where we would print garbage to the console instead of kernel function names, if the kernel wasn't built with symbol support (e.g. mboot). Make sure to tag every line of userspace backtrace output if we actually have the mmap_sem, since that way if there's no tag, we know that it's because we couldn't trylock the semaphore. Stop doing a TLB flush and examining page tables during backtrace. Instead, just trust that __copy_from_user_inatomic() will properly fault and return a failure, which it should do in all cases. Fix a latent bug where the backtracer would directly examine a signal context in user space, rather than copying it safely to kernel memory first. This meant that a race with another thread could potentially have caused a kernel panic. Guard against unaligned sp when trying to restart backtrace at an interrupt or signal handler point in the kernel backtracer. Report kernel symbolic information for the call instruction rather than for the following instruction. We still report the actual numeric address corresponding to the instruction after the call, for the sake of consistency with the normal expectations for stack backtracers. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: make sure to build memcpy_user_64 without frame pointerChris Metcalf
Add a comment explaining why this is important, and add a CFLAGS_REMOVE clause to the Makefile to make sure it happens. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: avoid false corrupt frame warning in early bootChris Metcalf
With lockstat we can end up trying to get a backtrace before "high_memory" is initialized, so don't worry about range testing if it is zero. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: use 0 for IRQ_RESCHEDULE instead of 1Chris Metcalf
This avoids assigning IRQ 0 to PCI devices, because we've seen that doesn't always work well. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: fix gcc 4.6 warnings in <asm/bitops_64.h>Chris Metcalf
Fix some signedness and variable usage warnings in change_bit() and test_and_change_bit(). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile: revert comment for atomic64_add_unless().Chris Metcalf
It still returns whether @v was not @u, not the old value, unlike __atomic_add_unless(). Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Arun Sharma <asharma@fb.com>
2012-04-02arch/tile: fix typo in <arch/spr_def.h>Chris Metcalf
We aren't yet using this definition in the kernel, but fix it up before someone goes looking for it. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile/Kconfig: don't specify CONFIG_PAGE_OFFSET for 64-bit buildsChris Metcalf
It's fixed at half the VA space and there's no point in configuring it. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile/Kconfig: rename tile_defconfig to tilepro_defconfigChris Metcalf
We switched to using "tilepro" for the 32-bit stuff a while ago, but missed this one usage. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02arch/tile/Kconfig: remove pointless "!M386" test.Chris Metcalf
Looks like a cut and paste bug from the x86 version. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02tile: fix multiple build failures from system.h dismantlePaul Gortmaker
Commit bd119c69239322caafdb64517a806037d0d0c70a "Disintegrate asm/system.h for Tile" created the asm/switch_to.h file, but did not add an include of it to all its users. Also, commit b4816afa3986704d1404fc48e931da5135820472 "Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h" introduced the concept of asm/cmpxchg.h but the tile arch never got one. Fork the cmpxchg content out of the asm/atomic.h file to create one. Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-04-02Merge tag 'for-linus' of git://github.com/rustyrussell/linuxLinus Torvalds
Pull cpumask cleanups from Rusty Russell: "(Somehow forgot to send this out; it's been sitting in linux-next, and if you don't want it, it can sit there another cycle)" I'm a sucker for things that actually delete lines of code. Fix up trivial conflict in arch/arm/kernel/kprobes.c, where Rusty fixed a user of &cpu_online_map to be cpu_online_mask, but that code got deleted by commit b21d55e98ac2 ("ARM: 7332/1: extract out code patch function from kprobes"). * tag 'for-linus' of git://github.com/rustyrussell/linux: cpumask: remove old cpu_*_map. documentation: remove references to cpu_*_map. drivers/cpufreq/db8500-cpufreq: remove references to cpu_*_map. remove references to cpu_*_map in arch/
2012-03-29Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tileLinus Torvalds
Pull arch/tile (really asm-generic) update from Chris Metcalf: "These are a couple of asm-generic changes that apply to tile." * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: compat: use sys_sendfile64() implementation for sendfile syscall [PATCH v3] ipc: provide generic compat versions of IPC syscalls
2012-03-29documentation: remove references to cpu_*_map.Rusty Russell
This has been obsolescent for a while, fix documentation and misc comments. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-03-29remove references to cpu_*_map in arch/Rusty Russell
This has been obsolescent for a while; time for the final push. In adjacent context, replaced old cpus_* with cpumask_*. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: David S. Miller <davem@davemloft.net> (arch/sparc) Acked-by: Chris Metcalf <cmetcalf@tilera.com> (arch/tile) Cc: user-mode-linux-devel@lists.sourceforge.net Cc: Russell King <linux@arm.linux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Cc: Richard Kuo <rkuo@codeaurora.org> Cc: linux-hexagon@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Helge Deller <deller@gmx.de> Cc: sparclinux@vger.kernel.org
2012-03-28Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds
Merge third batch of patches from Andrew Morton: - Some MM stragglers - core SMP library cleanups (on_each_cpu_mask) - Some IPI optimisations - kexec - kdump - IPMI - the radix-tree iterator work - various other misc bits. "That'll do for -rc1. I still have ~10 patches for 3.4, will send those along when they've baked a little more." * emailed from Andrew Morton <akpm@linux-foundation.org>: (35 commits) backlight: fix typo in tosa_lcd.c crc32: add help text for the algorithm select option mm: move hugepage test examples to tools/testing/selftests/vm mm: move slabinfo.c to tools/vm mm: move page-types.c from Documentation to tools/vm selftests/Makefile: make `run_tests' depend on `all' selftests: launch individual selftests from the main Makefile radix-tree: use iterators in find_get_pages* functions radix-tree: rewrite gang lookup using iterator radix-tree: introduce bit-optimized iterator fs/proc/namespaces.c: prevent crash when ns_entries[] is empty nbd: rename the nbd_device variable from lo to nbd pidns: add reboot_pid_ns() to handle the reboot syscall sysctl: use bitmap library functions ipmi: use locks on watchdog timeout set on reboot ipmi: simplify locking ipmi: fix message handling during panics ipmi: use a tasklet for handling received messages ipmi: increase KCS timeouts ipmi: decrease the IPMI message transaction time in interrupt mode ...
2012-03-28smp: introduce a generic on_each_cpu_mask() functionGilad Ben-Yossef
We have lots of infrastructure in place to partition multi-core systems such that we have a group of CPUs that are dedicated to specific task: cgroups, scheduler and interrupt affinity, and cpuisol= boot parameter. Still, kernel code will at times interrupt all CPUs in the system via IPIs for various needs. These IPIs are useful and cannot be avoided altogether, but in certain cases it is possible to interrupt only specific CPUs that have useful work to do and not the entire system. This patch set, inspired by discussions with Peter Zijlstra and Frederic Weisbecker when testing the nohz task patch set, is a first stab at trying to explore doing this by locating the places where such global IPI calls are being made and turning the global IPI into an IPI for a specific group of CPUs. The purpose of the patch set is to get feedback if this is the right way to go for dealing with this issue and indeed, if the issue is even worth dealing with at all. Based on the feedback from this patch set I plan to offer further patches that address similar issue in other code paths. This patch creates an on_each_cpu_mask() and on_each_cpu_cond() infrastructure API (the former derived from existing arch specific versions in Tile and Arm) and uses them to turn several global IPI invocation to per CPU group invocations. Core kernel: on_each_cpu_mask() calls a function on processors specified by cpumask, which may or may not include the local processor. You must not call this function with disabled interrupts or from a hardware interrupt handler or from a bottom half handler. arch/arm: Note that the generic version is a little different then the Arm one: 1. It has the mask as first parameter 2. It calls the function on the calling CPU with interrupts disabled, but this should be OK since the function is called on the other CPUs with interrupts disabled anyway. arch/tile: The API is the same as the tile private one, but the generic version also calls the function on the with interrupts disabled in UP case This is OK since the function is called on the other CPUs with interrupts disabled. Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> Reviewed-by: Christoph Lameter <cl@linux.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Sasha Levin <levinsasha928@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Avi Kivity <avi@redhat.com> Acked-by: Michal Nazarewicz <mina86@mina86.org> Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com> Cc: Milton Miller <miltonm@bga.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28Merge tag 'split-asm_system_h-for-linus-20120328' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system Pull "Disintegrate and delete asm/system.h" from David Howells: "Here are a bunch of patches to disintegrate asm/system.h into a set of separate bits to relieve the problem of circular inclusion dependencies. I've built all the working defconfigs from all the arches that I can and made sure that they don't break. The reason for these patches is that I recently encountered a circular dependency problem that came about when I produced some patches to optimise get_order() by rewriting it to use ilog2(). This uses bitops - and on the SH arch asm/bitops.h drags in asm-generic/get_order.h by a circuituous route involving asm/system.h. The main difficulty seems to be asm/system.h. It holds a number of low level bits with no/few dependencies that are commonly used (eg. memory barriers) and a number of bits with more dependencies that aren't used in many places (eg. switch_to()). These patches break asm/system.h up into the following core pieces: (1) asm/barrier.h Move memory barriers here. This already done for MIPS and Alpha. (2) asm/switch_to.h Move switch_to() and related stuff here. (3) asm/exec.h Move arch_align_stack() here. Other process execution related bits could perhaps go here from asm/processor.h. (4) asm/cmpxchg.h Move xchg() and cmpxchg() here as they're full word atomic ops and frequently used by atomic_xchg() and atomic_cmpxchg(). (5) asm/bug.h Move die() and related bits. (6) asm/auxvec.h Move AT_VECTOR_SIZE_ARCH here. Other arch headers are created as needed on a per-arch basis." Fixed up some conflicts from other header file cleanups and moving code around that has happened in the meantime, so David's testing is somewhat weakened by that. We'll find out anything that got broken and fix it.. * tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits) Delete all instances of asm/system.h Remove all #inclusions of asm/system.h Add #includes needed to permit the removal of asm/system.h Move all declarations of free_initmem() to linux/mm.h Disintegrate asm/system.h for OpenRISC Split arch_align_stack() out from asm-generic/system.h Split the switch_to() wrapper out of asm-generic/system.h Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h Create asm-generic/barrier.h Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h Disintegrate asm/system.h for Xtensa Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt] Disintegrate asm/system.h for Tile Disintegrate asm/system.h for Sparc Disintegrate asm/system.h for SH Disintegrate asm/system.h for Score Disintegrate asm/system.h for S390 Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PA-RISC Disintegrate asm/system.h for MN10300 ...
2012-03-28Delete all instances of asm/system.hDavid Howells
Delete all instances of asm/system.h as they should be redundant by this point. Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28Disintegrate asm/system.h for TileDavid Howells
Disintegrate asm/system.h for Tile. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com>
2012-03-23coredump: remove VM_ALWAYSDUMP flagJason Baron
The motivation for this patchset was that I was looking at a way for a qemu-kvm process, to exclude the guest memory from its core dump, which can be quite large. There are already a number of filter flags in /proc/<pid>/coredump_filter, however, these allow one to specify 'types' of kernel memory, not specific address ranges (which is needed in this case). Since there are no more vma flags available, the first patch eliminates the need for the 'VM_ALWAYSDUMP' flag. The flag is used internally by the kernel to mark vdso and vsyscall pages. However, it is simple enough to check if a vma covers a vdso or vsyscall page without the need for this flag. The second patch then replaces the 'VM_ALWAYSDUMP' flag with a new 'VM_NODUMP' flag, which can be set by userspace using new madvise flags: 'MADV_DONTDUMP', and unset via 'MADV_DODUMP'. The core dump filters continue to work the same as before unless 'MADV_DONTDUMP' is set on the region. The qemu code which implements this features is at: http://people.redhat.com/~jbaron/qemu-dump/qemu-dump.patch In my testing the qemu core dump shrunk from 383MB -> 13MB with this patch. I also believe that the 'MADV_DONTDUMP' flag might be useful for security sensitive apps, which might want to select which areas are dumped. This patch: The VM_ALWAYSDUMP flag is currently used by the coredump code to indicate that a vma is part of a vsyscall or vdso section. However, we can determine if a vma is in one these sections by checking it against the gate_vma and checking for a non-NULL return value from arch_vma_name(). Thus, freeing a valuable vma bit. Signed-off-by: Jason Baron <jbaron@redhat.com> Acked-by: Roland McGrath <roland@hack.frob.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Avi Kivity <avi@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-21Merge branch 'kmap_atomic' of git://github.com/congwang/linuxLinus Torvalds
Pull kmap_atomic cleanup from Cong Wang. It's been in -next for a long time, and it gets rid of the (no longer used) second argument to k[un]map_atomic(). Fix up a few trivial conflicts in various drivers, and do an "evil merge" to catch some new uses that have come in since Cong's tree. * 'kmap_atomic' of git://github.com/congwang/linux: (59 commits) feature-removal-schedule.txt: schedule the deprecated form of kmap_atomic() for removal highmem: kill all __kmap_atomic() [swarren@nvidia.com: highmem: Fix ARM build break due to __kmap_atomic rename] drbd: remove the second argument of k[un]map_atomic() zcache: remove the second argument of k[un]map_atomic() gma500: remove the second argument of k[un]map_atomic() dm: remove the second argument of k[un]map_atomic() tomoyo: remove the second argument of k[un]map_atomic() sunrpc: remove the second argument of k[un]map_atomic() rds: remove the second argument of k[un]map_atomic() net: remove the second argument of k[un]map_atomic() mm: remove the second argument of k[un]map_atomic() lib: remove the second argument of k[un]map_atomic() power: remove the second argument of k[un]map_atomic() kdb: remove the second argument of k[un]map_atomic() udf: remove the second argument of k[un]map_atomic() ubifs: remove the second argument of k[un]map_atomic() squashfs: remove the second argument of k[un]map_atomic() reiserfs: remove the second argument of k[un]map_atomic() ocfs2: remove the second argument of k[un]map_atomic() ntfs: remove the second argument of k[un]map_atomic() ...