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2009-06-24percpu: use dynamic percpu allocator as the default percpu allocatorTejun Heo1-3/+0
This patch makes most !CONFIG_HAVE_SETUP_PER_CPU_AREA archs use dynamic percpu allocator. The first chunk is allocated using embedding helper and 8k is reserved for modules. This ensures that the new allocator behaves almost identically to the original allocator as long as static percpu variables are concerned, so it shouldn't introduce much breakage. s390 and alpha use custom SHIFT_PERCPU_PTR() to work around addressing range limit the addressing model imposes. Unfortunately, this breaks if the address is specified using a variable, so for now, the two archs aren't converted. The following architectures are affected by this change. * sh * arm * cris * mips * sparc(32) * blackfin * avr32 * parisc (broken, under investigation) * m32r * powerpc(32) As this change makes the dynamic allocator the default one, CONFIG_HAVE_DYNAMIC_PER_CPU_AREA is replaced with its invert - CONFIG_HAVE_LEGACY_PER_CPU_AREA, which is added to yet-to-be converted archs. These archs implement their own setup_per_cpu_areas() and the conversion is not trivial. * powerpc(64) * sparc(64) * ia64 * alpha * s390 Boot and batch alloc/free tests on x86_32 with debug code (x86_32 doesn't use default first chunk initialization). Compile tested on sparc(32), powerpc(32), arm and alpha. Kyle McMartin reported that this change breaks parisc. The problem is still under investigation and he is okay with pushing this patch forward and fixing parisc later. [ Impact: use dynamic allocator for most archs w/o custom percpu setup ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Reviewed-by: Christoph Lameter <cl@linux.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mikael Starvik <starvik@axis.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Bryan Wu <cooloney@kernel.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: ensure percpu lpage doesn't consume too much vmalloc spaceTejun Heo1-3/+15
On extreme configuration (e.g. 32bit 32-way NUMA machine), lpage percpu first chunk allocator can consume too much of vmalloc space. Make it fall back to 4k allocator if the consumption goes over 20%. [ Impact: add sanity check for lpage percpu first chunk allocator ] Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jan Beulich <JBeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: implement percpu_alloc kernel parameterTejun Heo1-19/+50
According to Andi, it isn't clear whether lpage allocator is worth the trouble as there are many processors where PMD TLB is far scarcer than PTE TLB. The advantage or disadvantage probably depends on the actual size of percpu area and specific processor. As performance degradation due to TLB pressure tends to be highly workload specific and subtle, it is difficult to decide which way to go without more data. This patch implements percpu_alloc kernel parameter to allow selecting which first chunk allocator to use to ease debugging and testing. While at it, make sure all the failure paths report why something failed to help determining why certain allocator isn't working. Also, kill the "Great future plan" comment which had already been realized quite some time ago. [ Impact: allow explicit percpu first chunk allocator selection ] Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jan Beulich <JBeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: fix pageattr handling for lpage percpu allocator and re-enable itTejun Heo3-10/+93
lpage allocator aliases a PMD page for each cpu and returns whatever is unused to the page allocator. When the pageattr of the recycled pages are changed, this makes the two aliases point to the overlapping regions with different attributes which isn't allowed and known to cause subtle data corruption in certain cases. This can be handled in simliar manner to the x86_64 highmap alias. pageattr code should detect if the target pages have PMD alias and split the PMD alias and synchronize the attributes. pcpur allocator is updated to keep the allocated PMD pages map sorted in ascending address order and provide pcpu_lpage_remapped() function which binary searches the array to determine whether the given address is aliased and if so to which address. pageattr is updated to use pcpu_lpage_remapped() to detect the PMD alias and split it up as necessary from cpa_process_alias(). Jan Beulich spotted the original problem and incorrect usage of vaddr instead of laddr for lookup. With this, lpage percpu allocator should work correctly. Re-enable it. [ Impact: fix subtle lpage pageattr bug and re-enable lpage ] Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jan Beulich <JBeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: reorganize cpa_process_alias()Tejun Heo1-27/+23
Reorganize cpa_process_alias() so that new alias condition can be added easily. Jan Beulich spotted problem in the original cleanup thread which incorrectly assumed the two existing conditions were mutially exclusive. [ Impact: code reorganization ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Beulich <JBeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: prepare setup_pcpu_lpage() for pageattr fixTejun Heo1-25/+33
Make the following changes in preparation of coming pageattr updates. * Define and use array of struct pcpul_ent instead of array of pointers. The only difference is ->cpu field which is set but unused yet. * Rename variables according to the above change. * Rename local variable vm to pcpul_vm and move it out of the function. [ Impact: no functional difference ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Beulich <JBeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: rename remap percpu first chunk allocator to lpageTejun Heo1-25/+25
The "remap" allocator remaps large pages to build the first chunk; however, the name isn't very good because 4k allocator remaps too and the whole point of the remap allocator is using large page mapping. The allocator will be generalized and exported outside of x86, rename it to lpage before that happens. percpu_alloc kernel parameter is updated to accept both "remap" and "lpage" for lpage allocator. [ Impact: code cleanup, kernel parameter argument updated ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-22x86: fix duplicate free in setup_pcpu_remap() failure pathTejun Heo1-1/+1
In the failure path, setup_pcpu_remap() tries to free the area which has already been freed to make holes in the large page. Fix it. [ Impact: fix duplicate free in failure path ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-06-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds3-4/+9
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: crypto: aes-ni - Remove CRYPTO_TFM_REQ_MAY_SLEEP from fpu template crypto: aes-ni - Do not sleep when using the FPU crypto: aes-ni - Fix cbc mode IV saving crypto: padlock-aes - work around Nano CPU errata in CBC mode crypto: padlock-aes - work around Nano CPU errata in ECB mode
2009-06-21Move FAULT_FLAG_xyz into handle_mm_fault() callersLinus Torvalds1-1/+1
This allows the callers to now pass down the full set of FAULT_FLAG_xyz flags to handle_mm_fault(). All callers have been (mechanically) converted to the new calling convention, there's almost certainly room for architectures to clean up their code and then add FAULT_FLAG_RETRY when that support is added. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-20x86, 64-bit: Clean up user address maskingLinus Torvalds4-12/+4
The discussion about using "access_ok()" in get_user_pages_fast() (see commit 7f8189068726492950bf1a2dcfd9b51314560abf: "x86: don't use 'access_ok()' as a range check in get_user_pages_fast()" for details and end result), made us notice that x86-64 was really being very sloppy about virtual address checking. So be way more careful and straightforward about masking x86-64 virtual addresses: - All the VIRTUAL_MASK* variants now cover half of the address space, it's not like we can use the full mask on a signed integer, and the larger mask just invites mistakes when applying it to either half of the 48-bit address space. - /proc/kcore's kc_offset_to_vaddr() becomes a lot more obvious when it transforms a file offset into a (kernel-half) virtual address. - Unify/simplify the 32-bit and 64-bit USER_DS definition to be based on TASK_SIZE_MAX. This cleanup and more careful/obvious user virtual address checking also uncovered a buglet in the x86-64 implementation of strnlen_user(): it would do an "access_ok()" check on the whole potential area, even if the string itself was much shorter, and thus return an error even for valid strings. Our sloppy checking had hidden this. So this fixes 'strnlen_user()' to do this properly, the same way we already handled user strings in 'strncpy_from_user()'. Namely by just checking the first byte, and then relying on fault handling for the rest. That always works, since we impose a guard page that cannot be mapped at the end of the user space address space (and even if we didn't, we'd have the address space hole). Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-20Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds5-73/+143
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (49 commits) perfcounter: Handle some IO return values perf_counter: Push perf_sample_data through the swcounter code perf_counter tools: Define and use our own u64, s64 etc. definitions perf_counter: Close race in perf_lock_task_context() perf_counter, x86: Improve interactions with fast-gup perf_counter: Simplify and fix task migration counting perf_counter tools: Add a data file header perf_counter: Update userspace callchain sampling uses perf_counter: Make callchain samples extensible perf report: Filter to parent set by default perf_counter tools: Handle lost events perf_counter: Add event overlow handling fs: Provide empty .set_page_dirty() aop for anon inodes perf_counter: tools: Makefile tweaks for 64-bit powerpc perf_counter: powerpc: Add processor back-end for MPC7450 family perf_counter: powerpc: Make powerpc perf_counter code safe for 32-bit kernels perf_counter: powerpc: Change how processor-specific back-ends get selected perf_counter: powerpc: Use unsigned long for register and constraint values perf_counter: powerpc: Enable use of software counters on 32-bit powerpc perf_counter tools: Add and use isprint() ...
2009-06-20Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2-3/+11
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Fix out of scope variable access in sched_slice() sched: Hide runqueues from direct refer at source code level sched: Remove unneeded __ref tag sched, x86: Fix cpufreq + sched_clock() TSC scaling
2009-06-20Merge branch 'tracing-fixes-for-linus' of ↵Linus Torvalds4-2/+9
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits) tracing/urgent: warn in case of ftrace_start_up inbalance tracing/urgent: fix unbalanced ftrace_start_up function-graph: add stack frame test function-graph: disable when both x86_32 and optimize for size are configured ring-buffer: have benchmark test print to trace buffer ring-buffer: do not grab locks in nmi ring-buffer: add locks around rb_per_cpu_empty ring-buffer: check for less than two in size allocation ring-buffer: remove useless compile check for buffer_page size ring-buffer: remove useless warn on check ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index tracing: update sample event documentation tracing/filters: fix race between filter setting and module unload tracing/filters: free filter_string in destroy_preds() ring-buffer: use commit counters for commit pointer accounting ring-buffer: remove unused variable ring-buffer: have benchmark test handle discarded events ring-buffer: prevent adding write in discarded area tracing/filters: strloc should be unsigned short tracing/filters: operand can be negative ... Fix up kmemcheck-induced conflict in kernel/trace/ring_buffer.c manually
2009-06-20Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds37-597/+670
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: (45 commits) x86, mce: fix error path in mce_create_device() x86: use zalloc_cpumask_var for mce_dev_initialized x86: fix duplicated sysfs attribute x86: de-assembler-ize asm/desc.h i386: fix/simplify espfix stack switching, move it into assembly i386: fix return to 16-bit stack from NMI handler x86, ioapic: Don't call disconnect_bsp_APIC if no APIC present x86: Remove duplicated #include's x86: msr.h linux/types.h is only required for __KERNEL__ x86: nmi: Add Intel processor 0x6f4 to NMI perfctr1 workaround x86, mce: mce_intel.c needs <asm/apic.h> x86: apic/io_apic.c: dmar_msi_type should be static x86, io_apic.c: Work around compiler warning x86: mce: Don't touch THERMAL_APIC_VECTOR if no active APIC present x86: mce: Handle banks == 0 case in K7 quirk x86, boot: use .code16gcc instead of .code16 x86: correct the conversion of EFI memory types x86: cap iomem_resource to addressable physical memory x86, mce: rename _64.c files which are no longer 64-bit-specific x86, mce: mce.h cleanup ... Manually fix up trivial conflict in arch/x86/mm/fault.c
2009-06-20x86: don't use 'access_ok()' as a range check in get_user_pages_fast()Linus Torvalds1-2/+7
It's really not right to use 'access_ok()', since that is meant for the normal "get_user()" and "copy_from/to_user()" accesses, which are done through the TLB, rather than through the page tables. Why? access_ok() does both too few, and too many checks. Too many, because it is meant for regular kernel accesses that will not honor the 'user' bit in the page tables, and because it honors the USER_DS vs KERNEL_DS distinction that we shouldn't care about in GUP. And too few, because it doesn't do the 'canonical' check on the address on x86-64, since the TLB will do that for us. So instead of using a function that isn't meant for this, and does something else and much more complicated, just do the real rules: we don't want the range to overflow, and on x86-64, we want it to be a canonical low address (on 32-bit, all addresses are canonical). Acked-by: Ingo Molnar <mingo@elte.hu> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-20Merge branch 'x86/mce3' into x86/urgentIngo Molnar16-508/+528
2009-06-19perf_counter, x86: Improve interactions with fast-gupIngo Molnar2-2/+7
Improve a few details in perfcounter call-chain recording that makes use of fast-GUP: - Use ACCESS_ONCE() to observe the pte value. ptes are fundamentally racy and can be changed on another CPU, so we have to be careful about how we access them. The PAE branch is already careful with read-barriers - but the non-PAE and 64-bit side needs an ACCESS_ONCE() to make sure the pte value is observed only once. - make the checks a bit stricter so that we can feed it any kind of cra^H^H^H user-space input ;-) Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-19perf_counter: Make callchain samples extensiblePeter Zijlstra1-23/+6
Before exposing upstream tools to a callchain-samples ABI, tidy it up to make it more extensible in the future: Use markers in the IP chain to denote context, use (u64)-1..-4095 range for these context markers because we use them for ERR_PTR(), so these addresses are unlikely to be mapped. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-18function-graph: add stack frame testSteven Rostedt4-2/+9
In case gcc does something funny with the stack frames, or the return from function code, we would like to detect that. An arch may implement passing of a variable that is unique to the function and can be saved on entering a function and can be tested when exiting the function. Usually the frame pointer can be used for this purpose. This patch also implements this for x86. Where it passes in the stack frame of the parent function, and will test that frame on exit. There was a case in x86_32 with optimize for size (-Os) where, for a few functions, gcc would align the stack frame and place a copy of the return address into it. The function graph tracer modified the copy and not the actual return address. On return from the funtion, it did not go to the tracer hook, but returned to the parent. This broke the function graph tracer, because the return of the parent (where gcc did not do this funky manipulation) returned to the location that the child function was suppose to. This caused strange kernel crashes. This test detected the problem and pointed out where the issue was. This modifies the parameters of one of the functions that the arch specific code calls, so it includes changes to arch code to accommodate the new prototype. Note, I notice that the parsic arch implements its own push_return_trace. This is now a generic function and the ftrace_push_return_trace should be used instead. This patch does not touch that code. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Helge Deller <deller@gmx.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-18dma-mapping: x86: use asm-generic/dma-mapping-common.hFUJITA Tomonori2-171/+3
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Joerg Roedel <joerg.roedel@amd.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18gcov: enable GCOV_PROFILE_ALL for x86_64Peter Oberparleiter5-0/+6
Enable gcov profiling of the entire kernel on x86_64. Required changes include disabling profiling for: * arch/kernel/acpi/realmode and arch/kernel/boot/compressed: not linked to main kernel * arch/vdso, arch/kernel/vsyscall_64 and arch/kernel/hpet: profiling causes segfaults during boot (incompatible context) Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18x86, mce: fix error path in mce_create_device()Hidetoshi Seto1-5/+5
Don't skip removing mce_attrs in route from error2. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-18crypto: aes-ni - Remove CRYPTO_TFM_REQ_MAY_SLEEP from fpu templateHuang Ying1-2/+2
kernel_fpu_begin/end used preempt_disable/enable, so sleep should be prevented between kernel_fpu_begin/end. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-06-18crypto: aes-ni - Do not sleep when using the FPUHuang Ying1-0/+4
Because AES-NI instructions will touch XMM state, corresponding code must be enclosed within kernel_fpu_begin/end, which used preempt_disable/enable. So sleep should be prevented between kernel_fpu_begin/end. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-06-18crypto: aes-ni - Fix cbc mode IV savingHuang Ying1-2/+3
Original implementation of aesni_cbc_dec do not save IV if input length % 4 == 0. This will make decryption of next block failed. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-06-17x86: use zalloc_cpumask_var for mce_dev_initializedYinghai Lu1-1/+1
We need a cleared cpu_mask to record if mce is initialized, especially when MAXSMP is used. used zalloc_... instead Signed-off-by: Yinghai Lu <yinghai@kernel.org> Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: stable@kernel.org Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17x86: fix duplicated sysfs attributeYinghai Lu1-1/+1
The sysfs attribute cmci_disabled was accidentall turned into a duplicate of ignore_ce, breaking all other attributes. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Acked-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17x86: de-assembler-ize asm/desc.hAlexander van Heukelum4-29/+0
asm/desc.h is included in three assembly files, but the only macro it defines, GET_DESC_BASE, is never used. This patch removes the includes, removes the macro GET_DESC_BASE and the ASSEMBLY guard from asm/desc.h. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17i386: fix/simplify espfix stack switching, move it into assemblyAlexander van Heukelum2-16/+35
The espfix code triggers if we have a protected mode userspace application with a 16-bit stack. On returning to userspace, with iret, the CPU doesn't restore the high word of the stack pointer. This is an "official" bug, and the work-around used in the kernel is to temporarily switch to a 32-bit stack segment/pointer pair where the high word of the pointer is equal to the high word of the userspace stackpointer. The current implementation uses THREAD_SIZE to determine the cut-off, but there is no good reason not to use the more natural 64kb... However, implementing this by simply substituting THREAD_SIZE with 65536 in patch_espfix_desc crashed the test application. patch_espfix_desc tries to do what is described above, but gets it subtly wrong if the userspace stack pointer is just below a multiple of THREAD_SIZE: an overflow occurs to bit 13... With a bit of luck, when the kernelspace stackpointer is just below a 64kb-boundary, the overflow then ripples trough to bit 16 and userspace will see its stack pointer changed by 65536. This patch moves all espfix code into entry_32.S. Selecting a 16-bit cut-off simplifies the code. The game with changing the limit dynamically is removed too. It complicates matters and I see no value in it. Changing only the top 16-bit word of ESP is one instruction and it also implies that only two bytes of the ESPFIX GDT entry need to be changed and this can be implemented in just a handful simple to understand instructions. As a side effect, the operation to compute the original ESP from the ESPFIX ESP and the GDT entry simplifies a bit too, and the remaining three instructions have been expanded inline in entry_32.S. impact: can now reliably run userspace with ESP=xxxxfffc on 16-bit stack segment Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Stas Sergeev <stsp@aknet.ru> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17i386: fix return to 16-bit stack from NMI handlerAlexander van Heukelum1-6/+8
Returning to a task with a 16-bit stack requires special care: the iret instruction does not restore the high word of esp in that case. The espfix code fixes this, but currently is not invoked on NMIs. This means that a running task gets the upper word of esp clobbered due intervening NMIs. To reproduce, compile and run the following program with the nmi watchdog enabled (nmi_watchdog=2 on the command line). Using gdb you can see that the high bits of esp contain garbage, while the low bits are still correct. This patch puts the espfix code back into the NMI code path. The patch is slightly complicated due to the irqtrace infrastructure not being NMI-safe. The NMI return path cannot call TRACE_IRQS_IRET. Otherwise, the tail of the normal iret-code is correct for the nmi code path too. To be able to share this code-path, the TRACE_IRQS_IRET was move up a bit. The espfix code exists after the TRACE_IRQS_IRET, but this code explicitly disables interrupts. This short interrupts-off section is now not traced anymore. The return-to-kernel path now always includes the preliminary test to decide if the espfix code should be called. This is never the case, but doing it this way keeps the patch as simple as possible and the few extra instructions should not affect timing in any significant way. #define _GNU_SOURCE #include <stdio.h> #include <sys/types.h> #include <sys/mman.h> #include <unistd.h> #include <sys/syscall.h> #include <asm/ldt.h> int modify_ldt(int func, void *ptr, unsigned long bytecount) { return syscall(SYS_modify_ldt, func, ptr, bytecount); } /* this is assumed to be usable */ #define SEGBASEADDR 0x10000 #define SEGLIMIT 0x20000 /* 16-bit segment */ struct user_desc desc = { .entry_number = 0, .base_addr = SEGBASEADDR, .limit = SEGLIMIT, .seg_32bit = 0, .contents = 0, /* ??? */ .read_exec_only = 0, .limit_in_pages = 0, .seg_not_present = 0, .useable = 1 }; int main(void) { setvbuf(stdout, NULL, _IONBF, 0); /* map a 64 kb segment */ char *pointer = mmap((void *)SEGBASEADDR, SEGLIMIT+1, PROT_EXEC|PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, 0); if (pointer == NULL) { printf("could not map space\n"); return 0; } /* write ldt, new mode */ int err = modify_ldt(0x11, &desc, sizeof(desc)); if (err) { printf("error modifying ldt: %i\n", err); return 0; } for (int i=0; i<1000; i++) { asm volatile ( "pusha\n\t" "mov %ss, %eax\n\t" /* preserve ss:esp */ "mov %esp, %ebp\n\t" "push $7\n\t" /* index 0, ldt, user mode */ "push $65536-4096\n\t" /* esp */ "lss (%esp), %esp\n\t" /* switch to new stack */ "push %eax\n\t" /* save old ss:esp on new stack */ "push %ebp\n\t" "add $17*65536, %esp\n\t" /* set high bits */ "mov %esp, %edx\n\t" "mov $10000000, %ecx\n\t" /* wait... */ "1: loop 1b\n\t" /* ... a bit */ "cmp %esp, %edx\n\t" "je 1f\n\t" "ud2\n\t" /* esp changed inexplicably! */ "1:\n\t" "sub $17*65536, %esp\n\t" /* restore high bits */ "lss (%esp), %esp\n\t" /* restore old ss:esp */ "popa\n\t"); printf("\rx%ix", i); } return 0; } Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Stas Sergeev <stsp@aknet.ru> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-17x86: Use pci_claim_resourceMatthew Wilcox1-10/+7
Instead of open-coding pci_find_parent_resource and request_resource, just call pci_claim_resource. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-17x86, ioapic: Don't call disconnect_bsp_APIC if no APIC presentCyrill Gorcunov1-1/+3
Vegard Nossum reported: [ 503.576724] ACPI: Preparing to enter system sleep state S5 [ 503.710857] Disabling non-boot CPUs ... [ 503.716853] Power down. [ 503.717770] ------------[ cut here ]------------ [ 503.717770] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_du) [ 503.717770] Hardware name: OptiPlex GX100 [ 503.717770] Modules linked in: [ 503.717770] Pid: 2136, comm: halt Not tainted 2.6.30 #443 [ 503.717770] Call Trace: [ 503.717770] [<c154d327>] ? printk+0x18/0x1a [ 503.717770] [<c1017358>] ? native_apic_write_dummy+0x38/0x50 [ 503.717770] [<c10360fc>] warn_slowpath_common+0x6c/0xc0 [ 503.717770] [<c1017358>] ? native_apic_write_dummy+0x38/0x50 [ 503.717770] [<c1036165>] warn_slowpath_null+0x15/0x20 [ 503.717770] [<c1017358>] native_apic_write_dummy+0x38/0x50 [ 503.717770] [<c1017173>] disconnect_bsp_APIC+0x63/0x100 [ 503.717770] [<c1019e48>] disable_IO_APIC+0xb8/0xc0 [ 503.717770] [<c1214231>] ? acpi_power_off+0x0/0x29 [ 503.717770] [<c1015e55>] native_machine_shutdown+0x65/0x80 [ 503.717770] [<c1015c36>] native_machine_power_off+0x26/0x30 [ 503.717770] [<c1015c49>] machine_power_off+0x9/0x10 [ 503.717770] [<c1046596>] kernel_power_off+0x36/0x40 [ 503.717770] [<c104680d>] sys_reboot+0xfd/0x1f0 [ 503.717770] [<c109daa0>] ? perf_swcounter_event+0xb0/0x130 [ 503.717770] [<c109db7d>] ? perf_counter_task_sched_out+0x5d/0x120 [ 503.717770] [<c102dfc6>] ? finish_task_switch+0x56/0xd0 [ 503.717770] [<c154da1e>] ? schedule+0x49e/0xb40 [ 503.717770] [<c10444b0>] ? sys_kill+0x70/0x160 [ 503.717770] [<c119d9db>] ? selinux_file_ioctl+0x3b/0x50 [ 503.717770] [<c10dd443>] ? sys_ioctl+0x63/0x70 [ 503.717770] [<c1003024>] sysenter_do_call+0x12/0x22 [ 503.717770] ---[ end trace 8157b5d0ed378f15 ]--- | | That's including this commit: | | commit 103428e57be323c3c5545db8ad12667099bc6005 |Author: Cyrill Gorcunov <gorcunov@openvz.org> |Date: Sun Jun 7 16:48:40 2009 +0400 | | x86, apic: Fix dummy apic read operation together with broken MP handling | If we have apic disabled we don't even switch to APIC mode and do not calling for connect_bsp_APIC. Though on SMP compiled kernel the native_machine_shutdown does try to write the apic register anyway. Fix it with explicit check if we really should touch apic registers. Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <20090617181322.GG10822@lenovo> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17perf_counter: x86: Set the period in the intel overflow handlerPeter Zijlstra1-0/+2
Commit 9e350de37ac960 ("perf_counter: Accurate period data") missed a spot, which caused all Intel-PMU samples to have a period of 0. This broke auto-freq sampling. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86: Remove duplicated #include'sHuang Weiyi2-12/+0
Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com> LKML-Reference: <1244895686-2348-1-git-send-email-weiyi.huang@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86: msr.h linux/types.h is only required for __KERNEL__Jaswinder Singh Rajput1-6/+1
<linux/types.h> is only required for __KERNEL__ as whole file is covered with it Also fixed some spacing issues for usr/include/asm-x86/msr.h Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: "H. Peter Anvin" <hpa@kernel.org> LKML-Reference: <1245228070.2662.1.camel@ht.satnam> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17Merge branch 'fixes' of ↵Linus Torvalds6-189/+175
git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq: [CPUFREQ] cpumask: new cpumask operators for arch/x86/kernel/cpu/cpufreq/powernow-k8.c [CPUFREQ] cpumask: avoid playing with cpus_allowed in powernow-k8.c [CPUFREQ] cpumask: avoid cpumask games in arch/x86/kernel/cpu/cpufreq/speedstep-centrino.c [CPUFREQ] cpumask: avoid playing with cpus_allowed in speedstep-ich.c [CPUFREQ] powernow-k8: get drv data for correct CPU [CPUFREQ] powernow-k8: read P-state from HW [CPUFREQ] reduce scope of ACPI_PSS_BIOS_BUG_MSG[] [CPUFREQ] Clean up convoluted code in arch/x86/kernel/tsc.c:time_cpufreq_notifier() [CPUFREQ] minor correction to cpu-freq documentation [CPUFREQ] powernow-k8.c: mess cleanup [CPUFREQ] Only set sampling_rate_max deprecated, sampling_rate_min is useful [CPUFREQ] powernow-k8: Set transition latency to 1 if ACPI tables export 0 [CPUFREQ] ondemand: Uncouple minimal sampling rate from HZ in NO_HZ case
2009-06-17Merge branch 'x86/urgent' into x86/mce3Ingo Molnar15-24/+95
Conflicts: arch/x86/kernel/cpu/mcheck/mce_intel.c Merge reason: merge with an urgent-branch MCE fix. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86: nmi: Add Intel processor 0x6f4 to NMI perfctr1 workaroundPrarit Bhargava1-4/+8
Expand Intel NMI perfctr1 workaround to include a Core2 processor stepping (cpuid family-6, model-f, stepping-4). Resolves a situation where the NMI would not enable on these processors. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: prarit@redhat.com Cc: suresh.b.siddha@intel.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86, mce: mce_intel.c needs <asm/apic.h>H. Peter Anvin1-0/+1
mce_intel.c uses apic_write() and lapic_get_maxlvt(), and so it needs <asm/apic.h>. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
2009-06-17x86: apic/io_apic.c: dmar_msi_type should be staticJaswinder Singh Rajput1-1/+1
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86, io_apic.c: Work around compiler warningFigo.zhang1-1/+2
This compiler warning: arch/x86/kernel/apic/io_apic.c: In function ‘ioapic_write_entry’: arch/x86/kernel/apic/io_apic.c:466: warning: ‘eu’ is used uninitialized in this function arch/x86/kernel/apic/io_apic.c:465: note: ‘eu’ was declared here Is bogus as 'eu' is always initialized. But annotate it away by initializing the variable, to make it easier for people to notice real warnings. A compiler that sees through this logic will optimize away the initialization. Signed-off-by: Figo.zhang <figo1802@gmail.com> LKML-Reference: <1245248720.3312.27.camel@myhost> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86: mce: Don't touch THERMAL_APIC_VECTOR if no active APIC presentCyrill Gorcunov1-2/+8
If APIC was disabled (for some reason) and as result it's not even mapped we should not try to enable thermal interrupts at all. Reported-by: Simon Holm Thøgersen <odie@cs.aau.dk> Tested-by: Simon Holm Thøgersen <odie@cs.aau.dk> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> LKML-Reference: <20090615182633.GA7606@lenovo> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17sched, x86: Fix cpufreq + sched_clock() TSC scalingPeter Zijlstra2-3/+11
For freqency dependent TSCs we only scale the cycles, we do not account for the discrepancy in absolute value. Our current formula is: time = cycles * mult (where mult is a function of the cpu-speed on variable tsc machines) Suppose our current cycle count is 10, and we have a multiplier of 5, then our time value would end up being 50. Now cpufreq comes along and changes the multiplier to say 3 or 7, which would result in our time being resp. 30 or 70. That means that we can observe random jumps in the time value due to frequency changes in both fwd and bwd direction. So what this patch does is change the formula to: time = cycles * frequency + offset And we calculate offset so that time_before == time_after, thereby ridding us of these jumps in time. [ Impact: fix/reduce sched_clock() jumps across frequency changing events ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu> Chucked-on-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2009-06-17Merge branch 'linus' into perfcounters/coreIngo Molnar79-1716/+4805
Conflicts: arch/x86/include/asm/kmap_types.h include/linux/mm.h include/asm-generic/kmap_types.h Merge reason: We crossed changes with kmap_types.h cleanups in mainline. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17x86: mce: Handle banks == 0 case in K7 quirkAndi Kleen1-1/+1
Vegard Nossum reported: > I get an MCE-related crash like this in latest linus tree: > > [ 0.115341] CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line) > [ 0.116396] CPU: L2 Cache: 512K (64 bytes/line) > [ 0.120570] mce: CPU supports 0 MCE banks > [ 0.124870] BUG: unable to handle kernel NULL pointer dereference at 00000000 00000010 > [ 0.128001] IP: [<ffffffff813b98ad>] mcheck_init+0x278/0x320 > [ 0.128001] PGD 0 > [ 0.128001] Thread overran stack, or stack corrupted > [ 0.128001] Oops: 0002 [#1] PREEMPT SMP > [ 0.128001] last sysfs file: > [ 0.128001] CPU 0 > [ 0.128001] Modules linked in: > [ 0.128001] Pid: 0, comm: swapper Not tainted 2.6.30 #426 > [ 0.128001] RIP: 0010:[<ffffffff813b98ad>] [<ffffffff813b98ad>] mcheck_init+0x278/0x320 > [ 0.128001] RSP: 0018:ffffffff81595e38 EFLAGS: 00000246 > [ 0.128001] RAX: 0000000000000010 RBX: ffffffff8158f900 RCX: 0000000000000000 > [ 0.128001] RDX: 0000000000000000 RSI: 00000000000000ff RDI: 0000000000000010 > [ 0.128001] RBP: ffffffff81595e68 R08: 0000000000000001 R09: 0000000000000000 > [ 0.128001] R10: 0000000000000010 R11: 0000000000000000 R12: 0000000000000000 > [ 0.128001] R13: 00000000ffffffff R14: 0000000000000000 R15: 0000000000000000 > [ 0.128001] FS: 0000000000000000(0000) GS:ffff880002288000(0000) knlGS:00000 > 00000000000 > [ 0.128001] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > [ 0.128001] CR2: 0000000000000010 CR3: 0000000001001000 CR4: 00000000000006b0 > [ 0.128001] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 0.128001] DR3: 0000000000000000 DR6: 0000000000000000 DR7: 0000000000000000 > [ 0.128001] Process swapper (pid: 0, threadinfo ffffffff81594000, task ffffff > ff8152a4a0) > [ 0.128001] Stack: > [ 0.128001] 0000000081595e68 5aa50ed3b4ddbe6e ffffffff8158f900 ffffffff8158f > 914 > [ 0.128001] ffffffff8158f948 0000000000000000 ffffffff81595eb8 ffffffff813b8 > 69c > [ 0.128001] 5aa50ed3b4ddbe6e 00000001078bfbfd 0000062300000800 5aa50ed3b4ddb > e6e > [ 0.128001] Call Trace: > [ 0.128001] [<ffffffff813b869c>] identify_cpu+0x331/0x392 > [ 0.128001] [<ffffffff815a1445>] identify_boot_cpu+0x23/0x6e > [ 0.128001] [<ffffffff815a14ac>] check_bugs+0x1c/0x60 > [ 0.128001] [<ffffffff8159c075>] start_kernel+0x403/0x46e > [ 0.128001] [<ffffffff8159b2ac>] x86_64_start_reservations+0xac/0xd5 > [ 0.128001] [<ffffffff8159b3ea>] x86_64_start_kernel+0x115/0x14b > [ 0.128001] [<ffffffff8159b140>] ? early_idt_handler+0x0/0x71 This happens on QEMU which reports MCA capability, but no banks. Without this patch there is a buffer overrun and boot ops because the code would try to initialize the 0 element of a zero length kmalloc() buffer. Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Tested-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andi Kleen <ak@linux.intel.com> LKML-Reference: <20090615125200.GD31969@one.firstfloor.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17Merge branch 'linus' into x86/urgentIngo Molnar65-2099/+3773
Merge reason: pull in latest to fix a bug in it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-16Merge branch 'akpm'Linus Torvalds7-33/+10
* akpm: (182 commits) fbdev: bf54x-lq043fb: use kzalloc over kmalloc/memset fbdev: *bfin*: fix __dev{init,exit} markings fbdev: *bfin*: drop unnecessary calls to memset fbdev: bfin-t350mcqb-fb: drop unused local variables fbdev: blackfin has __raw I/O accessors, so use them in fb.h fbdev: s1d13xxxfb: add accelerated bitblt functions tcx: use standard fields for framebuffer physical address and length fbdev: add support for handoff from firmware to hw framebuffers intelfb: fix a bug when changing video timing fbdev: use framebuffer_release() for freeing fb_info structures radeon: P2G2CLK_ALWAYS_ONb tested twice, should 2nd be P2G2CLK_DAC_ALWAYS_ONb? s3c-fb: CPUFREQ frequency scaling support s3c-fb: fix resource releasing on error during probing carminefb: fix possible access beyond end of carmine_modedb[] acornfb: remove fb_mmap function mb862xxfb: use CONFIG_OF instead of CONFIG_PPC_OF mb862xxfb: restrict compliation of platform driver to PPC Samsung SoC Framebuffer driver: add Alpha Channel support atmel-lcdc: fix pixclock upper bound detection offb: use framebuffer_alloc() to allocate fb_info struct ... Manually fix up conflicts due to kmemcheck in mm/slab.c
2009-06-16kmap_types: make most arches use generic header fileRandy Dunlap1-20/+3
Convert most arches to use asm-generic/kmap_types.h. Move the KM_FENCE_ macro additions into asm-generic/kmap_types.h, controlled by __WITH_KM_FENCE from each arch's kmap_types.h file. Would be nice to be able to add custom KM_types per arch, but I don't yet see a nice, clean way to do that. Built on x86_64, i386, mips, sparc, alpha(tonyb), powerpc(tonyb), and 68k(tonyb). Note: avr32 should be able to remove KM_PTE2 (since it's not used) and then just use the generic kmap_types.h file. Get avr32 maintainer approval. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: <linux-arch@vger.kernel.org> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Bryan Wu <cooloney@kernel.org> Cc: Mikael Starvik <starvik@axis.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: "Luck Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: 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>
2009-06-16use printk_once() in several placesMinchan Kim1-8/+3
There are some places to be able to use printk_once instead of hard coding. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> 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>