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2008-10-13Merge branch 'proc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc * 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc: proc: remove kernel.maps_protect proc: remove now unneeded ADDBUF macro [PATCH] proc: show personality via /proc/pid/personality [PATCH] signal, procfs: some lock_task_sighand() users do not need rcu_read_lock() proc: move PROC_PAGE_MONITOR to fs/proc/Kconfig proc: make grab_header() static proc: remove unused get_dma_list() proc: remove dummy vmcore_open() proc: proc_sys_root tweak proc: fix return value of proc_reg_open() in "too late" case Fixed up trivial conflict in removed file arch/sparc/include/asm/dma_32.h
2008-10-11Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (236 commits) [ARM] 5300/1: fixup spitz reset during boot [ARM] 5295/1: make ZONE_DMA optional [ARM] 5239/1: Palm Zire 72 power management support [ARM] 5298/1: Drop desc_handle_irq() [ARM] 5297/1: [KS8695] Fix two compile-time warnings [ARM] 5296/1: [KS8695] Replace macro's with trailing underscores. [ARM] pxa: allow multi-machine PCMCIA builds [ARM] pxa: add preliminary CPUFREQ support for PXA3xx [ARM] pxa: add missing ACCR bit definitions to pxa3xx-regs.h [ARM] pxa: rename cpu-pxa.c to cpufreq-pxa2xx.c [ARM] pxa/zylonite: add support for USB OHCI [ARM] ohci-pxa27x: use ioremap() and offset for register access [ARM] ohci-pxa27x: introduce pxa27x_clear_otgph() [ARM] ohci-pxa27x: use platform_get_{irq,resource} for the resource [ARM] ohci-pxa27x: move OHCI controller specific registers into the driver [ARM] ohci-pxa27x: introduce flags to avoid direct access to OHCI registers [ARM] pxa: move I2S register and bit definitions into pxa2xx-i2s.c [ARM] pxa: simplify DMA register definitions [ARM] pxa: make additional DCSR bits valid for PXA3xx [ARM] pxa: move i2c register and bit definitions into i2c-pxa.c ... Fixed up conflicts in arch/arm/mach-versatile/core.c sound/soc/pxa/pxa2xx-ac97.c sound/soc/pxa/pxa2xx-i2s.c manually.
2008-10-10proc: remove unused get_dma_list()Alexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-09Merge branch 'pxa-all' into develRussell King
Conflicts: arch/arm/mach-pxa/Kconfig arch/arm/mach-pxa/corgi.c arch/arm/mach-pxa/include/mach/hardware.h arch/arm/mach-pxa/spitz.c
2008-10-09Merge branch 'ptebits' into develRussell King
Conflicts: arch/arm/Kconfig
2008-10-09[ARM] 5298/1: Drop desc_handle_irq()Dmitry Baryshkov
desc_handle_irq() was declared as obsolete since long ago. Replace it with generic_handle_irq() Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-10-08Merge branches 'sched/devel', 'sched/cpu-hotplug', 'sched/cpusets' and ↵Ingo Molnar
'sched/urgent' into sched/core
2008-10-02[ARM] 5274/1: simplify request_standard_resources()Nicolas Pitre
There is no point converting memory bank addresses from physical to virtual just to convert them back to physical addresses. Furthermore this isn't "right" for highmem even if in this case the end result is the correct one. Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-10-01[ARM] Improve non-executable supportRussell King
Add support for detecting non-executable stack binaries, and adjust permissions to prevent execution from data and stack areas. Also, ensure that READ_IMPLIES_EXEC is enabled for older CPUs where that is true, and for any executable-stack binary. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-30[ARM] mm: move vmalloc= parsing to arch/arm/mm/mmu.cRussell King
There's no point scattering this around the tree, the parsing of the parameter might as well live beside the code which uses it. That also means we can make vmalloc_reserve a static variable. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-26kgdb, x86, arm, mips, powerpc: ignore user space single steppingJason Wessel
On the x86 arch, user space single step exceptions should be ignored if they occur in the kernel space, such as ptrace stepping through a system call. First check if it is kgdb that is executing a single step, then ensure it is not an accidental traversal into the user space, while in kgdb, any other time the TIF_SINGLESTEP is set, kgdb should ignore the exception. On x86, arm, mips and powerpc, the kgdb_contthread usage was inconsistent with the way single stepping is implemented in the kgdb core. The arch specific stub should always set the kgdb_cpu_doing_single_step correctly if it is single stepping. This allows kgdb to correctly process an instruction steps if ptrace happens to be requesting an instruction step over a system call. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-25[ARM] Print details relevant to how we handle the cacheRussell King
This replaces the original cache type decoding printks. We now indicate how we're treating the cache which we found, rather than what we found. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-25[ARM] Introduce new bitmask based cache type macrosRussell King
Rather than trying to (inaccurately) decode the cache type from the registers each time we need to decide what type of cache we have, use a bitmask initialized early during boot. Since the setup is a one-off initialization, we can be a little more clever and take account of the CPU architecture as well. Note that we continue to achieve the compactness on optimised kernels by forcing tests to always-false or always-true as appropriate, thereby allowing the compiler to do build-time code elimination. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-25[ARM] Remove cache type printksRussell King
The cache type register found in ARMv5 and later CPUs changes format and meaning depending on the CPU architecture version. Currently, this code: a) doesn't work for everything - Xscale's are identified as 'unknown 5'. b) is not able to tell whether the caches are VIVT or VIPT from the cache type. c) prints rubbish on some ARMv6 and ARMv7+ CPUs. The two solutions to this are: 1. Add yet more code to decode and print the various different register formats. 2. Remove the code altogther. The code only exists to decode and print the cache parameters. Increasing the complexity of it just for the sake of a few prinks isn't worth it. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-08kernel/cpu.c: create a CPU_STARTING cpu_chain notifierManfred Spraul
Right now, there is no notifier that is called on a new cpu, before the new cpu begins processing interrupts/softirqs. Various kernel function would need that notification, e.g. kvm works around by calling smp_call_function_single(), rcu polls cpu_online_map. The patch adds a CPU_STARTING notification. It also adds a helper function that sends the message to all cpu_chain handlers. Tested on x86-64. All other archs are untested. Especially on sparc, I'm not sure if I got it right. Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06[ARM] Convert asm/io.h to linux/io.hRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-06[ARM] Convert asm/uaccess.h to linux/uaccess.hRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-06[ARM] clean up a load of old declarationsRussell King
... some of which are now in linux/*.h headers. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-06[ARM] move initrd code from kernel/setup.c to mm/init.cRussell King
This quietens some sparse warnings about phys_initrd_start and phys_initrd_size. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-06[ARM] remove pc_pointer()Russell King
pc_pointer() was a function to mask the PC for 26-bit ARMs, which we no longer support. Remove it. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-05[ARM] sparse: fix several warningsRussell King
arch/arm/kernel/process.c:270:6: warning: symbol 'show_fpregs' was not declared. Should it be static? This function isn't used, so can be removed. arch/arm/kernel/setup.c:532:9: warning: symbol 'len' shadows an earlier one arch/arm/kernel/setup.c:524:6: originally declared here A function containing two 'len's. arch/arm/mm/fault-armv.c:188:13: warning: symbol 'check_writebuffer_bugs' was not declared. Should it be static? arch/arm/mm/mmap.c:122:5: warning: symbol 'valid_phys_addr_range' was not declared. Should it be static? arch/arm/mm/mmap.c:137:5: warning: symbol 'valid_mmap_phys_addr_range' was not declared. Should it be static? Missing includes. arch/arm/kernel/traps.c:71:77: warning: Using plain integer as NULL pointer arch/arm/mm/ioremap.c:355:46: error: incompatible types in comparison expression (different address spaces) Sillies. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] 5227/1: Add the ENDPROC declarations to the .S filesCatalin Marinas
This declaration specifies the "function" type and size for various assembly functions, mainly needed for generating the correct branch instructions in Thumb-2. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] 5221/1: fix ldm/stm emulation for kprobesNicolas Pitre
Logic for the p bit was reversed. Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] 5206/1: remove kprobe_trap_handler() hackNicolas Pitre
As mentioned in commit 796969104cab0d454dbc792ad0d12a4f365a8564, and because of commit b03a5b7559563dafdbe52f8b5d8e453a914db941, the direct calling of kprobe_trap_handler() can be removed. Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] cachetype: move definitions to separate headerRussell King
Rather than pollute asm/cacheflush.h with the cache type definitions, move them to asm/cachetype.h, and include this new header where necessary. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] cputype: separate definitions, use themRussell King
Add asm/cputype.h, moving functions and definitions from asm/system.h there. Convert all users of 'processor_id' to the more efficient read_cpuid_id() function. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-16Merge master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds
* master.kernel.org:/home/rmk/linux-2.6-arm: (38 commits) [ARM] 5191/1: ARM: remove CVS keywords [ARM] pxafb: fix the warning of incorrect lccr when lcd_conn is specified [ARM] pxafb: add flag to specify output format on LDD pins when base is RGBT16 [ARM] pxafb: fix the incorrect configuration of GPIO77 as ACBIAS for TFT LCD [ARM] 5198/1: PalmTX: PCMCIA fixes [ARM] Fix a pile of broken watchdog drivers [ARM] update mach-types [ARM] 5196/1: fix inline asm constraints for preload [ARM] 5194/1: update .gitignore [ARM] add proc-macros.S include to proc-arm940 and proc-arm946 [ARM] 5192/1: ARM TLB: add v7wbi_{possible,always}_flags to {possible,always}_tlb_flags [ARM] 5193/1: Wire up missing syscalls [ARM] traps: don't call undef hook functions with spinlock held [ARM] 5183/2: Provide Poodle LoCoMo GPIO names [ARM] dma-mapping: provide sync_range APIs [ARM] dma-mapping: improve type-safeness of DMA translations [ARM] Kirkwood: instantiate the orion_spi driver in the platform code [ARM] prevent crashing when too much RAM installed [ARM] Kirkwood: Instantiate mv_xor driver [ARM] Orion: Instantiate mv_xor driver for 5182 ...
2008-08-15kexec jump: rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZEHuang Ying
Rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE, because control page is used for not only code on some platform. For example in kexec jump, it is used for data and stack too. [akpm@linux-foundation.org: unbreak powerpc and arm, finish conversion] Signed-off-by: Huang Ying <ying.huang@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-12[ARM] 5194/1: update .gitignoreNicolas Pitre
Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-12[ARM] 5193/1: Wire up missing syscallsStefan Schmidt
Setup some missing syscall pointed out by the checksyscalls.sh script. Fix two small whitespace issues while being there. Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-12[ARM] traps: don't call undef hook functions with spinlock heldRussell King
Calling the undefined instruction handler functions with a spinlock held is a recipe for must_sleep() warnings. Avoid it. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-09Merge branch 'for-rmk' of git://git.marvell.com/orionRussell King
2008-08-09[ARM] prevent crashing when too much RAM installedLennert Buytenhek
This patch will truncate and/or ignore memory banks if their kernel direct mappings would (partially) overlap with the vmalloc area or the mappings between the vmalloc area and the address space top, to prevent crashing during early boot if there happens to be more RAM installed than we are expecting. Since the start of the vmalloc area is not at a fixed address (but the vmalloc end address is, via the per-platform VMALLOC_END define), a default area of 128M is reserved for vmalloc mappings, which can be shrunk or enlarged by passing an appropriate vmalloc= command line option as it is done on x86. On a board with a 3:1 user:kernel split, VMALLOC_END at 0xfe000000, two 512M RAM banks and vmalloc=128M (the default), this patch gives: Truncating RAM at 20000000-3fffffff to -35ffffff (vmalloc region overlap). Memory: 512MB 352MB = 864MB total On a board with a 3:1 user:kernel split, VMALLOC_END at 0xfe800000, two 256M RAM banks and vmalloc=768M, this patch gives: Truncating RAM at 00000000-0fffffff to -0e7fffff (vmalloc region overlap). Ignoring RAM at 10000000-1fffffff (vmalloc region overlap). Signed-off-by: Lennert Buytenhek <buytenh@marvell.com> Tested-by: Riku Voipio <riku.voipio@iki.fi>
2008-08-07[ARM] Fix SMP booting with non-zero PHYS_OFFSETRussell King
The existing code tries to get the pmd for the temporary page table by doing: pgd = pgd_alloc(&init_mm); pmd = pmd_offset(pgd, PHYS_OFFSET); Since we have a two level page table, pmd_offset() is a no-op, so this just has a casting effect from a pgd to a pmd - the address argument is unused. So this can't work. Normally, we'd do: pgd = pgd_offset(&init_mm, PHYS_OFFSET); ... pmd = pmd_offset(pgd, PHYS_OFFSET); to get the pmd you want. However, pgd_offset() takes the mm_struct, not the (unattached) pgd we just allocated. So, instead use: pgd = pgd_alloc(&init_mm); pmd = pmd_offset(pgd + pgd_index(PHYS_OFFSET), PHYS_OFFSET); Reported-by: Antti P Miettinen <ananaza@iki.fi> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07[ARM] Move include/asm-arm/arch-* to arch/arm/*/include/machRussell King
This just leaves include/asm-arm/plat-* to deal with. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07[ARM] Remove asm/hardware.h, use asm/arch/hardware.h insteadRussell King
Remove includes of asm/hardware.h in addition to asm/arch/hardware.h. Then, since asm/hardware.h only exists to include asm/arch/hardware.h, update everything to directly include asm/arch/hardware.h and remove asm/hardware.h. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07[ARM] Eliminate useless includes of asm/mach-types.hRussell King
There are 43 includes of asm/mach-types.h by files that don't reference anything from that file. Remove these unnecessary includes. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07[ARM] Fix circular include dependency with IRQ headersRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-02[ARM] move include/asm-arm to arch/arm/include/asmRussell King
Move platform independent header files to arch/arm/include/asm, leaving those in asm/arch* and asm/plat* alone. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-07-25kprobes: improve kretprobe scalability with hashed lockingSrinivasa D S
Currently list of kretprobe instances are stored in kretprobe object (as used_instances,free_instances) and in kretprobe hash table. We have one global kretprobe lock to serialise the access to these lists. This causes only one kretprobe handler to execute at a time. Hence affects system performance, particularly on SMP systems and when return probe is set on lot of functions (like on all systemcalls). Solution proposed here gives fine-grain locks that performs better on SMP system compared to present kretprobe implementation. Solution: 1) Instead of having one global lock to protect kretprobe instances present in kretprobe object and kretprobe hash table. We will have two locks, one lock for protecting kretprobe hash table and another lock for kretporbe object. 2) We hold lock present in kretprobe object while we modify kretprobe instance in kretprobe object and we hold per-hash-list lock while modifying kretprobe instances present in that hash list. To prevent deadlock, we never grab a per-hash-list lock while holding a kretprobe lock. 3) We can remove used_instances from struct kretprobe, as we can track used instances of kretprobe instances using kretprobe hash table. Time duration for kernel compilation ("make -j 8") on a 8-way ppc64 system with return probes set on all systemcalls looks like this. cacheline non-cacheline Un-patched kernel aligned patch aligned patch =============================================================================== real 9m46.784s 9m54.412s 10m2.450s user 40m5.715s 40m7.142s 40m4.273s sys 2m57.754s 2m58.583s 3m17.430s =========================================================== Time duration for kernel compilation ("make -j 8) on the same system, when kernel is not probed. ========================= real 9m26.389s user 40m8.775s sys 2m7.283s ========================= Signed-off-by: Srinivasa DS <srinivasa@in.ibm.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: nohz: adjust tick_nohz_stop_sched_tick() call of s390 as well nohz: prevent tick stop outside of the idle loop
2008-07-24PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architecturesAndrea Righi
On 32-bit architectures PAGE_ALIGN() truncates 64-bit values to the 32-bit boundary. For example: u64 val = PAGE_ALIGN(size); always returns a value < 4GB even if size is greater than 4GB. The problem resides in PAGE_MASK definition (from include/asm-x86/page.h for example): #define PAGE_SHIFT 12 #define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT) #define PAGE_MASK (~(PAGE_SIZE-1)) ... #define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK) The "~" is performed on a 32-bit value, so everything in "and" with PAGE_MASK greater than 4GB will be truncated to the 32-bit boundary. Using the ALIGN() macro seems to be the right way, because it uses typeof(addr) for the mask. Also move the PAGE_ALIGN() definitions out of include/asm-*/page.h in include/linux/mm.h. See also lkml discussion: http://lkml.org/lkml/2008/6/11/237 [akpm@linux-foundation.org: fix drivers/media/video/uvc/uvc_queue.c] [akpm@linux-foundation.org: fix v850] [akpm@linux-foundation.org: fix powerpc] [akpm@linux-foundation.org: fix arm] [akpm@linux-foundation.org: fix mips] [akpm@linux-foundation.org: fix drivers/media/video/pvrusb2/pvrusb2-dvb.c] [akpm@linux-foundation.org: fix drivers/mtd/maps/uclinux.c] [akpm@linux-foundation.org: fix powerpc] Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-23kgdb: support for ARCH=armJason Wessel
This patch adds the ARCH=arm specific a kgdb backend, originally written by Deepak Saxena <dsaxena@plexity.net> and George Davis <gdavis@mvista.com>. Geoff Levand <geoffrey.levand@am.sony.com>, Nicolas Pitre, Manish Lachwani, and Jason Wessel have contributed various fixups here as well. The KGDB patch makes one change to the core ARM architecture such that the traps are initialized early for use with the debugger or other subsystems. [ mingo@elte.hu: small cleanups. ] [ ben-linux@fluff.org: fixed early_trap_init ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Deepak Saxena <dsaxena@plexity.net>
2008-07-21arm: bus_id -> dev_name() and dev_set_name() conversionsKay Sievers
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21sysdev: Pass the attribute to the low level sysdev show/store functionAndi Kleen
This allow to dynamically generate attributes and share show/store functions between attributes. Right now most attributes are generated by special macros and lots of duplicated code. With the attribute passed it's instead possible to attach some data to the attribute and then use that in shared low level functions to do different things. I need this for the dynamically generated bank attributes in the x86 machine check code, but it'll allow some further cleanups. I converted all users in tree to the new show/store prototype. It's a single huge patch to avoid unbisectable sections. Runtime tested: x86-32, x86-64 Compiled only: ia64, powerpc Not compile tested/only grep converted: sh, arm, avr32 Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21driver core: fix a lot of printk usages of bus_idGreg Kroah-Hartman
We have the dev_printk() variants for this kind of thing, use them instead of directly trying to access the bus_id field of struct device. This is done in order to remove bus_id entirely. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-18Merge branch 'linus' into timers/nohzIngo Molnar
2008-07-18nohz: prevent tick stop outside of the idle loopThomas Gleixner
Jack Ren and Eric Miao tracked down the following long standing problem in the NOHZ code: scheduler switch to idle task enable interrupts Window starts here ----> interrupt happens (does not set NEED_RESCHED) irq_exit() stops the tick ----> interrupt happens (does set NEED_RESCHED) return from schedule() cpu_idle(): preempt_disable(); Window ends here The interrupts can happen at any point inside the race window. The first interrupt stops the tick, the second one causes the scheduler to rerun and switch away from idle again and we end up with the tick disabled. The fact that it needs two interrupts where the first one does not set NEED_RESCHED and the second one does made the bug obscure and extremly hard to reproduce and analyse. Kudos to Jack and Eric. Solution: Limit the NOHZ functionality to the idle loop to make sure that we can not run into such a situation ever again. cpu_idle() { preempt_disable(); while(1) { tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we are in the idle loop while (!need_resched()) halt(); tick_nohz_restart_sched_tick(); <- disables NOHZ mode preempt_enable_no_resched(); schedule(); preempt_disable(); } } In hindsight we should have done this forever, but ... /me grabs a large brown paperbag. Debugged-by: Jack Ren <jack.ren@marvell.com>, Debugged-by: eric miao <eric.y.miao@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-07-15Merge branch 'generic-ipi' into generic-ipi-for-linusIngo Molnar
Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-15Merge branch 'core/stacktrace' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core/stacktrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: generic-ipi: powerpc/generic-ipi tree build failure stacktrace: fix build failure on sparc64 stacktrace: export save_stack_trace[_tsk] stacktrace: fix modular build, export print_stack_trace and save_stack_trace backtrace: replace timer with tasklet + completions stacktrace: add saved stack traces to backtrace self-test stacktrace: print_stack_trace() cleanup debugging: make stacktrace independent from DEBUG_KERNEL stacktrace: don't crash on invalid stack trace structs