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2009-03-02x86 mmiotrace: improve handling of secondary faultsStuart Bennett1-18/+22
Upgrade some kmmio.c debug messages to warnings. Allow secondary faults on probed pages to fall through, and only log secondary faults that are not due to non-present pages. Patch edited by Pekka Paalanen. Signed-off-by: Stuart Bennett <stuart@freedesktop.org> Signed-off-by: Pekka Paalanen <pq@iki.fi> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02x86 mmiotrace: split set_page_presence()Pekka Paalanen1-19/+22
From 36772dcb6ffbbb68254cbfc379a103acd2fbfefc Mon Sep 17 00:00:00 2001 From: Pekka Paalanen <pq@iki.fi> Date: Sat, 28 Feb 2009 21:34:59 +0200 Split set_page_presence() in kmmio.c into two more functions set_pmd_presence() and set_pte_presence(). Purely code reorganization, no functional changes. Signed-off-by: Pekka Paalanen <pq@iki.fi> Cc: Stuart Bennett <stuart@freedesktop.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02x86 mmiotrace: fix save/restore page table statePekka Paalanen1-22/+44
From baa99e2b32449ec7bf147c234adfa444caecac8a Mon Sep 17 00:00:00 2001 From: Pekka Paalanen <pq@iki.fi> Date: Sun, 22 Feb 2009 20:02:43 +0200 Blindly setting _PAGE_PRESENT in disarm_kmmio_fault_page() overlooks the possibility, that the page was not present when it was armed. Make arm_kmmio_fault_page() store the previous page presence in struct kmmio_fault_page and use it on disarm. This patch was originally written by Stuart Bennett, but Pekka Paalanen rewrote it a little different. Signed-off-by: Pekka Paalanen <pq@iki.fi> Cc: Stuart Bennett <stuart@freedesktop.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02x86 mmiotrace: WARN_ONCE if dis/arming a page failsStuart Bennett1-8/+17
Print a full warning once, if arming or disarming a page fails. Also, if initial arming fails, do not handle the page further. This avoids the possibility of a page failing to arm and then later claiming to have handled any fault on that page. WARN_ONCE added by Pekka Paalanen. Signed-off-by: Stuart Bennett <stuart@freedesktop.org> Signed-off-by: Pekka Paalanen <pq@iki.fi> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02x86: add far read test to testmmiotracePekka Paalanen1-7/+28
Apparently pages far into an ioremapped region might not actually be mapped during ioremap(). Add an optional read test to try to trigger a multiply faulting MMIO access. Also add more messages to the kernel log to help debugging. This patch is based on a patch suggested by Stuart Bennett <stuart@freedesktop.org> who discovered bugs in mmiotrace related to normal kernel space faults. Signed-off-by: Pekka Paalanen <pq@iki.fi> Cc: Stuart Bennett <stuart@freedesktop.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-02x86: count errors in testmmiotrace.koPekka Paalanen1-6/+29
Check the read values against the written values in the MMIO read/write test. This test shows if the given MMIO test area really works as memory, which is a prerequisite for a successful mmiotrace test. Signed-off-by: Pekka Paalanen <pq@iki.fi> Cc: Stuart Bennett <stuart@freedesktop.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-01Merge branch 'x86/urgent' into x86/patIngo Molnar2-11/+6
2009-03-01Revert "gpu/drm, x86, PAT: PAT support for io_mapping_*"Ingo Molnar1-42/+2
This reverts commit 17581ad812a9abb0182260374ef2e52d4a808a64. Sitsofe Wheeler reported that /dev/dri/card0 is MIA on his EeePC 900 and bisected it to this commit. Graphics card is an i915 in an EeePC 900: 00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller [8086:2592] (rev 04) ( Most likely the ioremap() of the driver failed and hence the card did not initialize. ) Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com> Bisected-by: Sitsofe Wheeler <sitsofe@yahoo.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-28x86: i915 needs pgprot_writecombine() and is_io_mapping_possible()Ingo Molnar2-11/+6
Impact: build fix Theodore Ts reported that the i915 driver needs these symbols: ERROR: "pgprot_writecombine" [drivers/gpu/drm/i915/i915.ko] undefined! ERROR: "is_io_mapping_possible" [drivers/gpu/drm/i915/i915.ko] undefined! Reported-by: Theodore Ts'o <tytso@mit.edu> wrote: Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-28x86, fixmap: define reserve_top_address for x86_64Gustavo F. Padovan2-16/+18
Impact: new interface (not yet use) Define reserve_top_address for x86_64; only for later x86 integration. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Acked-by: Glauber Costa <gcosta@redhat.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-02-26Merge branches 'x86/apic', 'x86/defconfig', 'x86/memtest', 'x86/mm' and ↵Ingo Molnar1-75/+81
'linus' into x86/core
2009-02-26Merge branches 'x86/urgent' and 'x86/pat' into x86/coreIngo Molnar2-19/+71
Conflicts: arch/x86/include/asm/pat.h
2009-02-26Merge branch 'x86/urgent' into x86/coreIngo Molnar1-0/+18
Conflicts: arch/x86/mach-voyager/voyager_smp.c
2009-02-26gpu/drm, x86, PAT: PAT support for io_mapping_*, export symbols for modulesIngo Molnar1-0/+2
Impact: build fix ERROR: "reserve_io_memtype_wc" [drivers/gpu/drm/i915/i915.ko] undefined! ERROR: "free_io_memtype" [drivers/gpu/drm/i915/i915.ko] undefined! Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25Merge branch 'x86/urgent' into x86/patIngo Molnar8-111/+242
2009-02-25gpu/drm, x86, PAT: PAT support for io_mapping_*Venkatesh Pallipadi1-2/+40
Make io_mapping_create_wc and io_mapping_free go through PAT to make sure that there are no memory type aliases. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Dave Airlie <airlied@redhat.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Eric Anholt <eric@anholt.net> Cc: Keith Packard <keithp@keithp.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25gpu/drm, x86, PAT: io_mapping_create_wc and resource_size_tVenkatesh Pallipadi1-0/+18
io_mapping_create_wc should take a resource_size_t parameter in place of unsigned long. With unsigned long, there will be no way to map greater than 4GB address in i386/32 bit. On x86, greater than 4GB addresses cannot be mapped on i386 without PAE. Return error for such a case. Patch also adds a structure for io_mapping, that saves the base, size and type on HAVE_ATOMIC_IOMAP archs, that can be used to verify the offset on io_mapping_map calls. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Dave Airlie <airlied@redhat.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Eric Anholt <eric@anholt.net> Cc: Keith Packard <keithp@keithp.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25gpu/drm, x86, PAT: routine to keep identity map in syncVenkatesh Pallipadi1-17/+29
Add a function to check and keep identity maps in sync, when changing any memory type. One of the follow on patches will also use this routine. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Dave Airlie <airlied@redhat.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Eric Anholt <eric@anholt.net> Cc: Keith Packard <keithp@keithp.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25x86: memtest: add additional (regular) test patternsAndreas Herrmann1-0/+13
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25x86: memtest: wipe out test pattern from memoryAndreas Herrmann1-23/+33
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25x86: memtest: adapt log messagesAndreas Herrmann1-20/+16
- print test pattern instead of pattern number, - show pattern as stored in memory, - use proper priority flags, - consistent use of u64 throughout the code Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25x86: memtest: cleanup memtest functionAndreas Herrmann1-18/+19
Impact: code cleanup Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25x86: memtest: introduce array to select memtest patternsAndreas Herrmann1-42/+23
Impact: code cleanup Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-25x86: memtest: reuse test patterns when memtest parameter exceeds number of ↵Andreas Herrmann1-2/+7
available patterns Impact: fix unexpected behaviour when pattern number is out of range Current implementation provides 4 patterns for memtest. The code doesn't check whether the memtest parameter value exceeds the maximum pattern number. Instead the memtest code pretends to test with non-existing patterns, e.g. when booting with memtest=10 I've observed the following ... early_memtest: pattern num 10 0000001000 - 0000006000 pattern 0 ... 0000001000 - 0000006000 pattern 1 ... 0000001000 - 0000006000 pattern 2 ... 0000001000 - 0000006000 pattern 3 ... 0000001000 - 0000006000 pattern 4 ... 0000001000 - 0000006000 pattern 5 ... 0000001000 - 0000006000 pattern 6 ... 0000001000 - 0000006000 pattern 7 ... 0000001000 - 0000006000 pattern 8 ... 0000001000 - 0000006000 pattern 9 ... But in fact Linux didn't test anything for patterns > 4 as the default case in memtest() is to leave the function. I suggest to use the memtest parameter as the number of tests to be performed and to re-iterate over all existing patterns. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-24Merge branch 'tj-percpu' of ↵Ingo Molnar2-19/+70
git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu Conflicts: arch/x86/include/asm/pgtable.h
2009-02-24Merge branches 'x86/acpi', 'x86/apic', 'x86/asm', 'x86/cleanups', 'x86/mm', ↵Ingo Molnar12-702/+1467
'x86/signal' and 'x86/urgent'; commit 'v2.6.29-rc6' into x86/core
2009-02-24x86: update populate_extra_pte() and add populate_extra_pmd()Tejun Heo2-33/+55
Impact: minor change to populate_extra_pte() and addition of pmd flavor Update populate_extra_pte() to return pointer to the pte_t for the specified address and add populate_extra_pmd() which only populates till the pmd and returns pointer to the pmd entry for the address. For 64bit, pud/pmd/pte fill functions are separated out from set_pte_vaddr[_pud]() and used for set_pte_vaddr[_pud]() and populate_extra_{pte|pmd}(). Signed-off-by: Tejun Heo <tj@kernel.org>
2009-02-22Merge branch 'linus' into x86/apicIngo Molnar2-11/+6
Conflicts: arch/x86/mach-default/setup.c Semantic conflict resolution: arch/x86/kernel/setup.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-22x86, mm: fault.c, simplify kmmio_fault(), cleanupIngo Molnar1-1/+2
Clarify the kmmio_fault() comment. Acked-by: Pekka Paalanen <pq@iki.fi> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-22x86: numa_32.c: fix sparse warning: Using plain integer as NULL pointerHannes Eder1-1/+1
Fix this sparse warning: arch/x86/mm/numa_32.c:197:24: warning: Using plain integer as NULL pointer Signed-off-by: Hannes Eder <hannes@hanneseder.net> Cc: trivial@kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, update copyrightsIngo Molnar1-0/+1
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, give another attempt at prefetch handing before SIGBUSIngo Molnar1-3/+1
Impact: extend prefetch handling on 64-bit Currently there's an extra is_prefetch() check done in do_sigbus(), which we only do on 32 bits. This is a last-ditch check before we terminate a task, so it's worth giving prefetch instructions another chance - should none of our existing quirks have caught a prefetch instruction related spurious fault. The only risk is if a prefetch causes a real sigbus, in that case we'll not OOM but try another fault. But this code has been on 32-bit for a long time, so it should be fine in practice. So do this on 64-bit too - and thus remove one more #ifdef. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, remove #ifdef from fault_in_kernel_space()Ingo Molnar1-4/+0
Impact: cleanup Removal of an #ifdef in fault_in_kernel_space(), by making use of the new TASK_SIZE_MAX symbol which is now available on 32-bit too. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: rename TASK_SIZE64 => TASK_SIZE_MAXIngo Molnar1-1/+1
Impact: cleanup Rename TASK_SIZE64 to TASK_SIZE_MAX, and provide the define on 32-bit too. (mapped to TASK_SIZE) This allows 32-bit code to make use of the (former-) TASK_SIZE64 symbol as well, in a clean way. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, remove #ifdef from do_page_fault()Ingo Molnar1-4/+2
Impact: cleanup do_page_fault() has this ugly #ifdef in its prototype: #ifdef CONFIG_X86_64 asmlinkage #endif void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) Replace it with 'dotraplinkage' which maps to exactly the above construct: nothing on 32-bit and asmlinkage on 64-bit. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, unify oops handlingIngo Molnar1-16/+3
Impact: add oops-recursion check to 32-bit Unify the oops state-machine, to the 64-bit version. It is slightly more careful in that it does a recursion check in oops_begin(), and is thus more likely to show the relevant oops. It also means that 32-bit will print one more line at the end of pagefault triggered oopses: printk(KERN_EMERG "CR2: %016lx\n", address); Which is generally good information to be seen in partial-dump digital-camera jpegs ;-) The downside is the somewhat more complex critical path. Both variants have been tested well meanwhile by kernel developers crashing their boxes so i dont think this is a practical worry. This removes 3 ugly #ifdefs from no_context() and makes the function a lot nicer read. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, unify oops printingIngo Molnar1-9/+5
Impact: refine/extend page fault related oops printing on 64-bit - honor the pause_on_oops logic on 64-bit too - print out NX fault warnings on 64-bit as well - factor out the NX fault message to make it git-greppable and readable Note that this means that we do the PF_INSTR check on 32-bit non-PAE as well where it should not occur ... normally. Cannot hurt. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, reorder functionsIngo Molnar1-235/+239
Impact: cleanup Avoid a couple more #ifdefs by moving fundamentally non-unifiable functions into a single #ifdef 32-bit / #else / #endif block in fault.c: vmalloc*(), dump_pagetable(), check_vm8086_mode(). No code changed: text data bss dec hex filename 4618 32 24 4674 1242 fault.o.before 4618 32 24 4674 1242 fault.o.after Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm, kprobes: fault.c, simplify notify_page_fault()Ingo Molnar1-5/+1
Impact: cleanup Remove an #ifdef from notify_page_fault(). The function still compiles to nothing in the !CONFIG_KPROBES case. Introduce kprobes_built_in() and kprobe_fault_handler() helpers to allow this - they returns 0 if !CONFIG_KPROBES. No code changed: text data bss dec hex filename 4618 32 24 4674 1242 fault.o.before 4618 32 24 4674 1242 fault.o.after Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, simplify kmmio_fault()Ingo Molnar1-2/+3
Impact: cleanup Remove an #ifdef from kmmio_fault() - we can do this by providing default implementations for is_kmmio_active() and kmmio_handler(). The compiler optimizes it all away in the !CONFIG_MMIOTRACE case. Also, while at it, clean up mmiotrace.h a bit: - standard header guards - standard vertical spaces for structure definitions No code changed (both with mmiotrace on and off in the config): text data bss dec hex filename 2947 12 12 2971 b9b fault.o.before 2947 12 12 2971 b9b fault.o.after Cc: Pekka Paalanen <pq@iki.fi> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, enable PF_RSVD checks on 32-bit tooIngo Molnar1-4/+0
Impact: improve page fault handling robustness The 'PF_RSVD' flag (bit 3) of the page-fault error_code is a relatively recent addition to x86 CPUs, so the 32-bit do_fault() implementation never had it. This flag gets set when the CPU detects nonzero values in any reserved bits of the page directory entries. Extend the existing 64-bit check for PF_RSVD in do_page_fault() to 32-bit too. If we detect such a fault then we print a more informative oops and the pagetables. This unifies the code some more, removes an ugly #ifdef and improves the 32-bit page fault code robustness a bit. It slightly increases the 32-bit kernel text size. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, factor out the vm86 fault checkIngo Molnar1-12/+31
Impact: cleanup Instead of an ugly, open-coded, #ifdef-ed vm86 related legacy check in do_page_fault(), put it into the check_v8086_mode() helper function and merge it with an existing #ifdef. Also, simplify the code flow a tiny bit in the helper. No code changed: arch/x86/mm/fault.o: text data bss dec hex filename 2711 12 12 2735 aaf fault.o.before 2711 12 12 2735 aaf fault.o.after Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-21x86, mm: fault.c, refactor/simplify the is_prefetch() codeIngo Molnar1-50/+50
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 Molnar1-215/+331
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 Rostedt2-8/+64
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 Molnar1-1/+12
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 Molnar1-0/+7
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 Rostedt1-1/+12
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 Molnar2-11/+6
2009-02-20x86: use the right protections for split-up pagetablesIngo Molnar1-10/+5
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>
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