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2009-02-21x86, mm: fault.c, refactor/simplify the is_prefetch() codeIngo Molnar
Impact: no functionality changed Factor out the opcode checker into a helper inline. The code got a tiny bit smaller: text data bss dec hex filename 4632 32 24 4688 1250 fault.o.before 4618 32 24 4674 1242 fault.o.after And it got cleaner / easier to review as well. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c cleanupIngo Molnar
Impact: cleanup, no code changed Clean up various small details, which can be correctness checked automatically: - tidy up the include file section - eliminate unnecessary includes - introduce show_signal_msg() to clean up code flow - standardize the code flow - standardize comments and other style details - more cleanups, pointed out by checkpatch No code changed on either 32-bit nor 64-bit: arch/x86/mm/fault.o: text data bss dec hex filename 4632 32 24 4688 1250 fault.o.before 4632 32 24 4688 1250 fault.o.after the md5 changed due to a change in a single instruction: 2e8a8241e7f0d69706776a5a26c90bc0 fault.o.before.asm c5c3d36e725586eb74f0e10692f0193e fault.o.after.asm Because a __LINE__ reference in a WARN_ONCE() has changed. On 32-bit a few stack offsets changed - no code size difference nor any functionality difference. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-20ftrace, x86: make kernel text writable only for conversionsSteven Rostedt
Impact: keep kernel text read only Because dynamic ftrace converts the calls to mcount into and out of nops at run time, we needed to always keep the kernel text writable. But this defeats the point of CONFIG_DEBUG_RODATA. This patch converts the kernel code to writable before ftrace modifies the text, and converts it back to read only afterward. The kernel text is converted to read/write, stop_machine is called to modify the code, then the kernel text is converted back to read only. The original version used SYSTEM_STATE to determine when it was OK or not to change the code to rw or ro. Andrew Morton pointed out that using SYSTEM_STATE is a bad idea since there is no guarantee to what its state will actually be. Instead, I moved the check into the set_kernel_text_* functions themselves, and use a local variable to determine when it is OK to change the kernel text RW permissions. [ Update: Ingo Molnar suggested moving the prototypes to cacheflush.h ] Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-20Merge branch 'tip/x86/urgent' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into x86/mm
2009-02-20x86, pat: add large-PAT check to split_large_page()Ingo Molnar
Impact: future-proof the split_large_page() function Linus noticed that split_large_page() is not safe wrt. the PAT bit: it is bit 12 on the 1GB and 2MB page table level (_PAGE_BIT_PAT_LARGE), and it is bit 7 on the 4K page table level (_PAGE_BIT_PAT). Currently it is not a problem because we never set _PAGE_BIT_PAT_LARGE on any of the large-page mappings - but should this happen in the future the split_large_page() would silently lift bit 12 into the lowlevel 4K pte and would start corrupting the physical page frame offset. Not fun. So add a debug warning, to make sure if something ever sets the PAT bit then this function gets updated too. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-20x86: check PMD in spurious_fault handlerSteven Rostedt
Impact: fix to prevent hard lockup on bad PMD permissions If the PMD does not have the correct permissions for a page access, but the PTE does, the spurious fault handler will mistake the fault as a lazy TLB transaction. This will result in an infinite loop of: fault -> spurious_fault check (pass) -> return to code -> fault This patch adds a check and a warn on if the PTE passes the permissions but the PMD does not. [ Updated: Ingo Molnar suggested using WARN_ONCE with some text ] Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-20Merge branch 'x86/urgent' into x86/coreIngo Molnar
2009-02-20x86: use the right protections for split-up pagetablesIngo Molnar
Steven Rostedt found a bug in where in his modified kernel ftrace was unable to modify the kernel text, due to the PMD itself having been marked read-only as well in split_large_page(). The fix, suggested by Linus, is to not try to 'clone' the reference protection of a huge-page, but to use the standard (and permissive) page protection bits of KERNPG_TABLE. The 'cloning' makes sense for the ptes but it's a confused and incorrect concept at the page table level - because the pagetable entry is a set of all ptes and hence cannot 'clone' any single protection attribute - the ptes can be any mixture of protections. With the permissive KERNPG_TABLE, even if the pte protections get changed after this point (due to ftrace doing code-patching or other similar activities like kprobes), the resulting combined protections will still be correct and the pte's restrictive (or permissive) protections will control it. Also update the comment. This bug was there for a long time but has not caused visible problems before as it needs a rather large read-only area to trigger. Steve possibly hacked his kernel with some really large arrays or so. Anyway, the bug is definitely worth fixing. [ Huang Ying also experienced problems in this area when writing the EFI code, but the real bug in split_large_page() was not realized back then. ] Reported-by: Steven Rostedt <rostedt@goodmis.org> Reported-by: Huang Ying <ying.huang@intel.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-20x86: convert to the new dynamic percpu allocatorTejun Heo
Impact: use new dynamic allocator, unified access to static/dynamic percpu memory Convert to the new dynamic percpu allocator. * implement populate_extra_pte() for both 32 and 64 * update setup_per_cpu_areas() to use pcpu_setup_static() * define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() * define config HAVE_DYNAMIC_PER_CPU_AREA Signed-off-by: Tejun Heo <tj@kernel.org>
2009-02-18mm: clean up for early_pfn_to_nid()KAMEZAWA Hiroyuki
What's happening is that the assertion in mm/page_alloc.c:move_freepages() is triggering: BUG_ON(page_zone(start_page) != page_zone(end_page)); Once I knew this is what was happening, I added some annotations: if (unlikely(page_zone(start_page) != page_zone(end_page))) { printk(KERN_ERR "move_freepages: Bogus zones: " "start_page[%p] end_page[%p] zone[%p]\n", start_page, end_page, zone); printk(KERN_ERR "move_freepages: " "start_zone[%p] end_zone[%p]\n", page_zone(start_page), page_zone(end_page)); printk(KERN_ERR "move_freepages: " "start_pfn[0x%lx] end_pfn[0x%lx]\n", page_to_pfn(start_page), page_to_pfn(end_page)); printk(KERN_ERR "move_freepages: " "start_nid[%d] end_nid[%d]\n", page_to_nid(start_page), page_to_nid(end_page)); ... And here's what I got: move_freepages: Bogus zones: start_page[2207d0000] end_page[2207dffc0] zone[fffff8103effcb00] move_freepages: start_zone[fffff8103effcb00] end_zone[fffff8003fffeb00] move_freepages: start_pfn[0x81f600] end_pfn[0x81f7ff] move_freepages: start_nid[1] end_nid[0] My memory layout on this box is: [ 0.000000] Zone PFN ranges: [ 0.000000] Normal 0x00000000 -> 0x0081ff5d [ 0.000000] Movable zone start PFN for each node [ 0.000000] early_node_map[8] active PFN ranges [ 0.000000] 0: 0x00000000 -> 0x00020000 [ 0.000000] 1: 0x00800000 -> 0x0081f7ff [ 0.000000] 1: 0x0081f800 -> 0x0081fe50 [ 0.000000] 1: 0x0081fed1 -> 0x0081fed8 [ 0.000000] 1: 0x0081feda -> 0x0081fedb [ 0.000000] 1: 0x0081fedd -> 0x0081fee5 [ 0.000000] 1: 0x0081fee7 -> 0x0081ff51 [ 0.000000] 1: 0x0081ff59 -> 0x0081ff5d So it's a block move in that 0x81f600-->0x81f7ff region which triggers the problem. This patch: Declaration of early_pfn_to_nid() is scattered over per-arch include files, and it seems it's complicated to know when the declaration is used. I think it makes fix-for-memmap-init not easy. This patch moves all declaration to include/linux/mm.h After this, if !CONFIG_NODES_POPULATES_NODE_MAP && !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID -> Use static definition in include/linux/mm.h else if !CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID -> Use generic definition in mm/page_alloc.c else -> per-arch back end function will be called. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reported-by: David Miller <davem@davemlloft.net> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-17Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, vm86: fix preemption bug x86, olpc: fix model detection without OFW x86, hpet: fix for LS21 + HPET = boot hang x86: CPA avoid repeated lazy mmu flush x86: warn if arch_flush_lazy_mmu_cpu is called in preemptible context x86/paravirt: make arch_flush_lazy_mmu/cpu disable preemption x86, pat: fix warn_on_once() while mapping 0-1MB range with /dev/mem x86/cpa: make sure cpa is safe to call in lazy mmu mode x86, ptrace, mm: fix double-free on race
2009-02-17x86, apic: remove duplicate asm/apic.h inclusionsIngo Molnar
Impact: cleanup Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17x86, apic: remove genapic.hIngo Molnar
Impact: cleanup Remove genapic.h and remove all references to it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-13Merge branch 'x86/untangle2' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen into x86/headers Conflicts: arch/x86/include/asm/page.h arch/x86/include/asm/pgtable.h arch/x86/mach-voyager/voyager_smp.c arch/x86/mm/fault.c
2009-02-13Merge branches 'x86/paravirt', 'x86/pat', 'x86/setup-v2', 'x86/subarch', ↵Ingo Molnar
'x86/uaccess' and 'x86/urgent' into x86/core
2009-02-13Merge branch 'x86/mm' into x86/coreIngo Molnar
2009-02-13Merge branches 'x86/acpi', 'x86/asm', 'x86/cpudetect', 'x86/crashdump', ↵Ingo Molnar
'x86/debug', 'x86/defconfig', 'x86/doc', 'x86/header-fixes', 'x86/headers' and 'x86/minor-fixes' into x86/core
2009-02-13Merge branch 'core/percpu' into x86/coreIngo Molnar
2009-02-13Merge branch 'linus' into x86/apicIngo Molnar
Conflicts: arch/x86/kernel/acpi/boot.c arch/x86/mm/fault.c
2009-02-12x86: CPA avoid repeated lazy mmu flushThomas Gleixner
Impact: Flush the lazy MMU only once Pending mmu updates only need to be flushed once to bring the in-memory pagetable state up to date. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-02-12x86, 32-bit: refactor find_low_pfn_range()Ingo Molnar
Impact: cleanup Make the max_low_pfn logic a bit more standard between lowmem_pfn_init() and highmem_pfn_init(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-12x86, 32-bit: clean up find_low_pfn_range()Ingo Molnar
Impact: cleanup Split find_low_pfn_range() into two functions: - lowmem_pfn_init() - highmem_pfn_init() The former gets called if all of RAM fits into lowmem, otherwise we call highmem_pfn_init(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-12x86: fix warning in find_low_pfn_range()Ingo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-12x86, pat: fix warn_on_once() while mapping 0-1MB range with /dev/memSuresh Siddha
Jeff Mahoney reported: > With Suse's hwinfo tool, on -tip: > WARNING: at arch/x86/mm/pat.c:637 reserve_pfn_range+0x5b/0x26d() reserve_pfn_range() is not tracking the memory range below 1MB as non-RAM and as such is inconsistent with similar checks in reserve_memtype() and free_memtype() Rename the pagerange_is_ram() to pat_pagerange_is_ram() and add the "track legacy 1MB region as non RAM" condition. And also, fix reserve_pfn_range() to return -EINVAL, when the pfn range is RAM. This is to be consistent with this API design. Reported-and-tested-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-12x86/cpa: make sure cpa is safe to call in lazy mmu modeJeremy Fitzhardinge
Impact: fix race leading to crash under KVM and Xen The CPA code may be called while we're in lazy mmu update mode - for example, when using DEBUG_PAGE_ALLOC and doing a slab allocation in an interrupt handler which interrupted a lazy mmu update. In this case, the in-memory pagetable state may be out of date due to pending queued updates. We need to flush any pending updates before inspecting the page table. Similarly, we must explicitly flush any modifications CPA may have made (which comes down to flushing queued operations when flushing the TLB). Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Marcelo Tosatti <mtosatti@redhat.com> Cc: Stable Kernel <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11x86: mm/init_32.c fix compilation warningJaswinder Singh Rajput
arch/x86/mm/init_32.c: In function ‘find_low_pfn_range’: arch/x86/mm/init_32.c:696: warning: format ‘%u’ expects type ‘unsigned int’, but Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11Merge commit 'remotes/tip/x86/paravirt' into x86/untangle2Jeremy Fitzhardinge
* commit 'remotes/tip/x86/paravirt': (175 commits) xen: use direct ops on 64-bit xen: make direct versions of irq_enable/disable/save/restore to common code xen: setup percpu data pointers xen: fix 32-bit build resulting from mmu move x86/paravirt: return full 64-bit result x86, percpu: fix kexec with vmlinux x86/vmi: fix interrupt enable/disable/save/restore calling convention. x86/paravirt: don't restore second return reg xen: setup percpu data pointers x86: split loading percpu segments from loading gdt x86: pass in cpu number to switch_to_new_gdt() x86: UV fix uv_flush_send_and_wait() x86/paravirt: fix missing callee-save call on pud_val x86/paravirt: use callee-saved convention for pte_val/make_pte/etc x86/paravirt: implement PVOP_CALL macros for callee-save functions x86/paravirt: add register-saving thunks to reduce caller register pressure x86/paravirt: selectively save/restore regs around pvops calls x86: fix paravirt clobber in entry_64.S x86/pvops: add a paravirt_ident functions to allow special patching xen: move remaining mmu-related stuff into mmu.c ... Conflicts: arch/x86/mach-voyager/voyager_smp.c arch/x86/mm/fault.c
2009-02-10Merge branch 'x86/uaccess' into core/percpuIngo Molnar
2009-02-09Merge commit 'v2.6.29-rc4' into core/percpuIngo Molnar
Conflicts: arch/x86/mach-voyager/voyager_smp.c arch/x86/mm/fault.c
2009-02-09x86: fix abuse of per_cpu_offsetBrian Gerst
Impact: bug fix Don't use per_cpu_offset() to determine if it valid to access a per-cpu variable for a given cpu number. It is not a valid assumption on x86-64 anymore. Use cpu_possible() instead. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06Merge branch 'linus' into x86/mmIngo Molnar
Conflicts: arch/x86/mm/fault.c
2009-02-05prevent kprobes from catching spurious page faultsMasami Hiramatsu
Prevent kprobes from catching spurious faults which will cause infinite recursive page-fault and memory corruption by stack overflow. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: <stable@kernel.org> [2.6.28.x] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-04x86: mm: introduce helper function in fault.cHiroshi Shimamoto
Impact: cleanup Introduce helper function fault_in_kernel_address() to make editors happy. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-01-31x86: update copyrightsIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86: add might_sleep() to do_page_fault()Peter Zijlstra
Impact: widen debug checks VirtualBox calls do_page_fault() from an atomic context but runs into a might_sleep() way pas this point, cure that. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86: replace CONFIG_X86_SMP with CONFIG_SMPIngo Molnar
The x86/Voyager subarch used to have this distinction between 'x86 SMP support' and 'Voyager SMP support': config X86_SMP bool depends on SMP && ((X86_32 && !X86_VOYAGER) || X86_64) This is a pointless distinction - Voyager can (and already does) use smp_ops to implement various SMP quirks it has - and it can be extended more to cover all the specialities of Voyager. So remove this complication in the Kconfig space. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86, smp: remove mach_ipi.hIngo Molnar
Move mach_ipi.h definitions into genapic.h. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-28x86, apic: untangle the send_IPI_*() jungleIngo Molnar
Our send_IPI_*() methods and definitions are a twisted mess: the same symbol is defined to different things depending on .config details, in a non-transparent way. - spread out the quirks into separately named per apic driver methods - prefix the standard PC methods with default_ - get rid of wrapper macro obfuscation - clean up various details Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-28Merge branches 'x86/asm', 'x86/cleanups', 'x86/cpudetect', 'x86/debug', ↵Ingo Molnar
'x86/doc', 'x86/header-fixes', 'x86/mm', 'x86/paravirt', 'x86/pat', 'x86/setup-v2', 'x86/subarch', 'x86/uaccess' and 'x86/urgent' into x86/core
2009-01-27Merge branch 'tj-percpu' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu Conflicts: arch/x86/kernel/setup_percpu.c Semantic conflict: arch/x86/kernel/cpu/common.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-27Merge branch 'linus' into core/percpuIngo Molnar
Conflicts: arch/x86/kernel/setup_percpu.c
2009-01-27x86: move 64-bit NUMA codeBrian Gerst
Impact: Code movement, no functional change. Move the 64-bit NUMA code from setup_percpu.c to numa_64.c Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2009-01-26Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (29 commits) xen: unitialised return value in xenbus_write_transaction x86: fix section mismatch warning x86: unmask CPUID levels on Intel CPUs, fix x86: work around PAGE_KERNEL_WC not getting WC in iomap_atomic_prot_pfn. x86: use standard PIT frequency xen: handle highmem pages correctly when shrinking a domain x86, mm: fix pte_free() xen: actually release memory when shrinking domain x86: unmask CPUID levels on Intel CPUs x86: add MSR_IA32_MISC_ENABLE bits to <asm/msr-index.h> x86: fix PTE corruption issue while mapping RAM using /dev/mem x86: mtrr fix debug boot parameter x86: fix page attribute corruption with cpa() Revert "x86: signal: change type of paramter for sys_rt_sigreturn()" x86: use early clobbers in usercopy*.c x86: remove kernel_physical_mapping_init() from init section fix: crash: IP: __bitmap_intersects+0x48/0x73 cpufreq: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write work_on_cpu: Use our own workqueue. work_on_cpu: don't try to get_online_cpus() in work_on_cpu. ...
2009-01-26x86: work around PAGE_KERNEL_WC not getting WC in iomap_atomic_prot_pfn.Eric Anholt
In the absence of PAT, PAGE_KERNEL_WC ends up mapping to a memory type that gets UC behavior even in the presence of a WC MTRR covering the area in question. By swapping to PAGE_KERNEL_UC_MINUS, we can get the actual behavior the caller wanted (WC if you can manage it, UC otherwise). This recovers the 40% performance improvement of using WC in the DRM to upload vertex data. Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-01-23x86: handle PAT more like other CPU featuresH. Peter Anvin
Impact: Cleanup When PAT was originally introduced, it was handled specially for a few reasons: - PAT bugs are hard to track down, so we wanted to maintain a whitelist of CPUs. - The i386 and x86-64 CPUID code was not yet unified. Both of these are now obsolete, so handle PAT like any other features, including ordinary feature blacklisting due to known bugs. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-01-23x86: uaccess: introduce try and catch frameworkHiroshi Shimamoto
Impact: introduce new uaccess exception handling framework Introduce {get|put}_user_try and {get|put}_user_catch as new uaccess exception handling framework. {get|put}_user_try begins exception block and {get|put}_user_catch(err) ends the block and gets err if an exception occured in {get|put}_user_ex() in the block. The exception is stored thread_info->uaccess_err. The example usage of this framework is below; int func() { int err = 0; get_user_try { get_user_ex(...); get_user_ex(...); : } get_user_catch(err); return err; } Note: get_user_ex() is not clear the value when an exception occurs, it's different from the behavior of __get_user(), but I think it doesn't matter. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-01-22x86 PAT: ioremap_wc should take resource_size_t parametervenkatesh.pallipadi@intel.com
Impact: fix/extend ioremap_wc() beyond 4GB aperture on 32-bit ioremap_wc() was taking in unsigned long parameter, where as it should take 64-bit resource_size_t parameter like other ioremap variants. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-21x86: optimise page fault entry, cleanupJohannes Weiner
tsk is already assigned to current, drop the redundant second assignment. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-21x86: fix PTE corruption issue while mapping RAM using /dev/memSuresh Siddha
Beschorner Daniel reported: > hwinfo problem since 2.6.28, showing this in the oops: > Corrupted page table at address 7fd04de3ec00 Also, PaX Team reported a regression with this commit: > commit 9542ada803198e6eba29d3289abb39ea82047b92 > Author: Suresh Siddha <suresh.b.siddha@intel.com> > Date: Wed Sep 24 08:53:33 2008 -0700 > > x86: track memtype for RAM in page struct This commit breaks mapping any RAM page through /dev/mem, as the reserve_memtype() was not initializing the return attribute type and as such corrupting the PTE entry that was setup with the return attribute type. Because of this bug, application mapping this RAM page through /dev/mem will die with "Corrupted page table at address xxxx" message in the kernel log and also the kernel identity mapping which maps the underlying RAM page gets converted to UC. Fix this by initializing the return attribute type before calling reserve_ram_pages_type() Reported-by: PaX Team <pageexec@freemail.hu> Reported-and-tested-by: Beschorner Daniel <Daniel.Beschorner@facton.com> Tested-and-Acked-by: PaX Team <pageexec@freemail.hu> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-21x86: fix page attribute corruption with cpa()Suresh Siddha
Impact: fix sporadic slowdowns and warning messages This patch fixes a performance issue reported by Linus on his Nehalem system. While Linus reverted the PAT patch (commit 58dab916dfb57328d50deb0aa9b3fc92efa248ff) which exposed the issue, existing cpa() code can potentially still cause wrong(page attribute corruption) behavior. This patch also fixes the "WARNING: at arch/x86/mm/pageattr.c:560" that various people reported. In 64bit kernel, kernel identity mapping might have holes depending on the available memory and how e820 reports the address range covering the RAM, ACPI, PCI reserved regions. If there is a 2MB/1GB hole in the address range that is not listed by e820 entries, kernel identity mapping will have a corresponding hole in its 1-1 identity mapping. If cpa() happens on the kernel identity mapping which falls into these holes, existing code fails like this: __change_page_attr_set_clr() __change_page_attr() returns 0 because of if (!kpte). But doesn't set cpa->numpages and cpa->pfn. cpa_process_alias() uses uninitialized cpa->pfn (random value) which can potentially lead to changing the page attribute of kernel text/data, kernel identity mapping of RAM pages etc. oops! This bug was easily exposed by another PAT patch which was doing cpa() more often on kernel identity mapping holes (physical range between max_low_pfn_mapped and 4GB), where in here it was setting the cache disable attribute(PCD) for kernel identity mappings aswell. Fix cpa() to handle the kernel identity mapping holes. Retain the WARN() for cpa() calls to other not present address ranges (kernel-text/data, ioremap() addresses) Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>