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Some BIOSes use PMU resources, which can cause various bugs:
- Non-working or erratic PMU based statistics - the PMU can end up
counting the wrong thing, resulting in misleading statistics
- Profiling can stop working or it can profile the wrong thing
- A non-working or erratic NMI watchdog that cannot be relied on
- The kernel may disturb whatever thing the BIOS tries to use the
PMU for - possibly causing hardware malfunction in extreme cases.
- ... and other forms of potential misbehavior
Various forms of such misbehavior has been observed in practice - there are
BIOSes that just corrupt the PMU state, consequences be damned.
The PMU is a CPU resource that is handled by the kernel and the BIOS
stealing+corrupting it is not acceptable nor robust, so we detect it,
warn about it and further refuse to touch the PMU ourselves.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Merge reason: We want to apply a dependent patch.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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When adjusting the code to handle removing the old nmi watchdog,
I forgot to consider the compile case when the local apic is not
enabled.
This change fixes the following build error:
arch/x86/kernel/apic/hw_nmi.c:28:6: error: redefinition of ‘touch_nmi_watchdog’
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Rakib Mullick <rakib.mullick@gmail.com>
LKML-Reference: <20101213153719.GD18577@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Fix a typo in:
004417a6d468: perf, arch: Cleanup perf-pmu init vs lockup-detector
Which caused a build failure on Sparc, reported by Stephen Rothwell.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Originally adapted from Huang Ying's patch which moved the
unknown_nmi_panic to the traps.c file. Because the old nmi
watchdog was deleted before this change happened, the
unknown_nmi_panic sysctl was lost. This re-adds it.
Also, the nmi_watchdog sysctl was re-implemented and its
documentation updated accordingly.
Patch-inspired-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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My patch that removed the old x86 nmi watchdog broke other
arches. This change reverts a piece of that patch and puts the
change in the correct spot.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: fweisbec@gmail.com
Cc: yinghai@kernel.org
LKML-Reference: <1291068437-5331-2-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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arch/x86/kernel/apic/hw_nmi.c:29: warning: backtrace_mask defined but not used
commit 0e2af2a9(x86, hw_nmi: Move backtrace_mask declaration under
ARCH_HAS_NMI_WATCHDOG) addressed this warning, but it was reintroduced
by commit 5f2b0ba4(x86, nmi_watchdog: Remove the old nmi_watchdog).
Move backtrace_mask into the #ifdef arch_trigger_all_cpu_backtrace
section again.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <AANLkTi=rcc38QzoKa6LFy4m++-p_9=Zt4_kDQE=GeKxf@mail.gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Since all the hotplug stuff is serialized by the hotplug mutex,
do away with the amd_nb_lock.
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86/pvclock: Zero last_value on resume
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf record: Fix eternal wait for stillborn child
perf header: Don't assume there's no attr info if no sample ids is provided
perf symbols: Figure out start address of kernel map from kallsyms
perf symbols: Fix kallsyms kernel/module map splitting
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
nohz: Fix printk_needs_cpu() return value on offline cpus
printk: Fix wake_up_klogd() vs cpu hotplug
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* 'fixes/2637-rc5/s3c24xx' of git://git.fluff.org/bjdooks/linux:
ARM: S3C24XX: Fix mess with gpio {set,get}_pull callbacks
ARM: mini2440: Fix Kconfig to allow kernel to build
ARM: S3C2412: Fix typo in CONFIG_CPU_S3C2412_ONLY definition
ARM: S3C2443: Select properly ARM core type
ARM: SMDK2416: Select MACH_SMDK, S3C_DEV_NAND, S3C_DEV_USB_HOST
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Currently the {set,get}_pull callbacks of the s3c24xx_gpiocfg_default structure
are initalized via s3c_gpio_{get,set}pull_1up. This results in a linker
error when only CONFIG_CPU_S3C2442 is selected:
arch/arm/plat-s3c24xx/built-in.o:(.data+0x13f4): undefined reference to
`s3c_gpio_getpull_1up'
arch/arm/plat-s3c24xx/built-in.o:(.data+0x13f8): undefined reference to
`s3c_gpio_setpull_1up'
The s3c2442 has pulldowns instead of pullups compared to the s3c2440.
The method of controlling them is the same though.
So this patch modifies the existing s3c_gpio_{get,set}pull_1up helper functions
to take an additional parameter deciding whether the pin has a pullup or pulldown.
The s3c_gpio_{get,set}pull_1{down,up} functions then wrap that functions passing
either S3C_GPIO_PULL_UP or S3C_GPIO_PULL_DOWN.
Furthermore this patch sets up the s3c24xx_gpiocfg_default.{get,set}_pull fields
in the s3c244{0,2}_map_io function to the new pulldown helper functions.
Based on patch from "Lars-Peter Clausen" <lars@metafoo.de>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
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Fix the name of interrupt mask alteration function (ie the
local_change_intr_mask_level() fn) called in gdbstub to have an arch_
prefix to match the definition in asm/irqflags.h.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6:
[S390] css: fix rsid evaluation for 2nd crw
[S390] nohz/s390: fix arch_needs_cpu() return value on offline cpus
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Merge reason: Pick up the latest -rc.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Commit 0ea129300982 ("arm: return both physical and virtual addresses
from addruart") took out the test for MMU on/off but didn't switch the
ldr instructions to no longer be conditionals based on said test.
Fix that.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* master.kernel.org:/home/rmk/linux-2.6-arm:
ARM: 6524/1: GIC irq desciptor bug fix
ARM: 6523/1: iop: ensure sched_clock() is notrace
ARM: 6456/1: Fix for building DEBUG with sa11xx_base.c as a module.
ARM: 6519/1: kuser: Fix incorrect cmpxchg syscall in kuser helpers
ARM: 6505/1: kprobes: Don't HAVE_KPROBES when CONFIG_THUMB2_KERNEL is selected
ARM: 6508/1: vexpress: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
ARM: 6507/1: RealView: Correct data alignment in headsmp.S for CONFIG_THUMB2_KERNEL
ARM: 6504/1: Thumb-2: Fix long-distance conditional branches in head.S for Thumb-2.
ARM: 6503/1: Thumb-2: Restore sensible zImage header layout for CONFIG_THUMB2_KERNEL
ARM: 6502/1: Thumb-2: Fix CONFIG_THUMB2_KERNEL breakage in compressed/head.S
ARM: 6501/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in mm/proc-v7.S
ARM: 6500/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in kernel/head.S
ARM: 6499/1: Thumb-2: Correct data alignment for CONFIG_THUMB2_KERNEL in bootp/init.S
ARM: 6498/1: vfp: Correct data alignment for CONFIG_THUMB2_KERNEL
ARM: 6497/1: kexec: Correct data alignment for CONFIG_THUMB2_KERNEL
ARM: 6496/1: GIC: Do not try to register more then NR_IRQS interrupts
ARM: cns3xxx: Fix build with CONFIG_PCI=y
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Use text_poke_smp_batch() on unoptimization path for reducing
the number of stop_machine() issues. If the number of
unoptimizing probes is more than MAX_OPTIMIZE_PROBES(=256),
kprobes unoptimizes first MAX_OPTIMIZE_PROBES probes and kicks
optimizer for remaining probes.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101203095434.2961.22657.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Use text_poke_smp_batch() in optimization path for reducing
the number of stop_machine() issues. If the number of optimizing
probes is more than MAX_OPTIMIZE_PROBES(=256), kprobes optimizes
first MAX_OPTIMIZE_PROBES probes and kicks optimizer for
remaining probes.
Changes in v5:
- Use kick_kprobe_optimizer() instead of directly calling
schedule_delayed_work().
- Rescheduling optimizer outside of kprobe mutex lock.
Changes in v2:
- Allocate code buffer and parameters in arch_init_kprobes()
instead of using static arraies.
- Merge previous max optimization limit patch into this patch.
So, this patch introduces upper limit of optimization at
once.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101203095428.2961.8994.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Introduce text_poke_smp_batch(). This function modifies several
text areas with one stop_machine() on SMP. Because calling
stop_machine() is heavy task, it is better to aggregate
text_poke requests.
( Note: I've talked with Rusty about this interface, and
he would not like to expand stop_machine() interface, since
it is not for generic use. )
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095422.2961.51217.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Unoptimization occurs when a probe is unregistered or disabled,
and is heavy because it recovers instructions by using
stop_machine(). This patch delays unoptimization operations and
unoptimize several probes at once by using
text_poke_smp_batch(). This can avoid unexpected system slowdown
coming from stop_machine().
Changes in v5:
- Split this patch into several cleanup patches and this patch.
- Fix some text_mutex lock miss.
- Use bool instead of int for behavior flags.
- Add additional comment for (un)optimizing path.
Changes in v2:
- Use dynamic allocated buffers and params.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095409.2961.82733.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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gic_set_cpu will directly use irq_desc[]. If CONFIG_SPARSE_IRQ is
enabled, there is no irq_desc[]. So we need use irq_to_desc(irq) to
get the descriptor for irq.
Signed-off-by: Chao Xie <chao.xie@marvell.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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git://git.kernel.org/pub/scm/linux/kernel/git/kyle/parisc-2.6
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kyle/parisc-2.6:
parisc: Fix GSC PS/2 driver name for keyboard and mouse
parisc: KittyHawk LCD fix
parisc: convert the rest of the irq handlers to simple/percpu
parisc: fix dino/gsc interrupts
parisc: remove redundant initialization in sigsegv path of sys_rt_sigreturn
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The generic conversion eliminates the spurious no_ack and no_end
routines, converts all the cascaded handlers to handle_simple_irq() and
makes iosapic use a modified handle_percpu_irq() to become the same as
the CPU irq's. This isn't an essential change, but it eliminates the
mask/unmask overhead of handle_level_irq().
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
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The essential problem we're currently having is that dino (and gsc) is a
cascaded CPU interrupt. Under the old __do_IRQ() handler, our CPU
interrupts basically did an ack followed by an end. In the new scheme,
we replaced them with level handlers which do a mask, an ack and then an
unmask (but no end). Instead, with the renaming of end to eoi, we
actually want to call the percpu flow handlers, because they actually
have all the characteristics we want.
This patch does the conversion and gets my C360 booting again.
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
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Include sched.h to ensure sched_clock() has the notrace
annotation, and mark any functions it calls as notrace
too.
Include sched.h to ensure sched_clock() has the notrace
annotation, and mark any functions it calls as notrace
too.
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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The existing code invokes the syscall with rubbish in r7,
due to what looks like an incorrect literal load idiom.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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git://xenbits.xen.org/people/sstabellini/linux-pvhvm
* '2.6.37-rc4-pvhvm-fixes' of git://xenbits.xen.org/people/sstabellini/linux-pvhvm:
xen: unplug the emulated devices at resume time
xen: fix save/restore for PV on HVM guests with pirq remapping
xen: resume the pv console for hvm guests too
xen: fix MSI setup and teardown for PV on HVM guests
xen: use PHYSDEVOP_get_free_pirq to implement find_unbound_pirq
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The MACH_MINI2440 entry requires the backlight LED driver, but this
subsystem has not been enabled and the select of LEDS_TRIGGER_BACKLIGHT
alone is insufficient to enable the necessary bits of the LED driver.
Add NEW_LEDS, LEDS_CLASS and LEDS_TRIGGER to the select to allow the
kernel to link.
This fixes the following error:
drivers/built-in.o: In function `led_trigger_set':
/home/ben/linux.git/drivers/leds/led-triggers.c:116: undefined reference to `led_brightness_set'
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
* 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
xen: allocate irq descs on any NUMA node
xen: prevent crashes with non-HIGHMEM 32-bit kernels with largeish memory
xen: use default_idle
xen: clean up "extra" memory handling some more
* 'upstream/bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
xen: x86/32: perform initial startup on initial_page_table
xen: don't bother to stop other cpus on shutdown/reboot
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git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6
* 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
sh: se/7724: Remove FSI/B of GPIO init code
sh: se/7724: Update clock framework of FSI clock to non-legacy
sh: Assume new page cache pages have dirty dcache lines.
sh: boards: mach-se: use IS_ERR() instead of NULL check
sh: Add div6_reparent_clks to clock framework for FSI
dma: shdma: add a MODULE_ALIAS() to allow module autoloading
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Implement asm/syscall.h for the MN10300 arch.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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se7724 board does not have FSI/B.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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On stock 2.6.37-rc4, running:
# mount lilith:/export /mnt/lilith
# find /mnt/lilith/ -type f -print0 | xargs -0 file
crashes the machine fairly quickly under Xen. Often it results in oops
messages, but the couple of times I tried just now, it just hung quietly
and made Xen print some rude messages:
(XEN) mm.c:2389:d80 Bad type (saw 7400000000000001 != exp
3000000000000000) for mfn 1d7058 (pfn 18fa7)
(XEN) mm.c:964:d80 Attempt to create linear p.t. with write perms
(XEN) mm.c:2389:d80 Bad type (saw 7400000000000010 != exp
1000000000000000) for mfn 1d2e04 (pfn 1d1fb)
(XEN) mm.c:2965:d80 Error while pinning mfn 1d2e04
Which means the domain tried to map a pagetable page RW, which would
allow it to map arbitrary memory, so Xen stopped it. This is because
vm_unmap_ram() left some pages mapped in the vmalloc area after NFS had
finished with them, and those pages got recycled as pagetable pages
while still having these RW aliases.
Removing those mappings immediately removes the Xen-visible aliases, and
so it has no problem with those pages being reused as pagetable pages.
Deferring the TLB flush doesn't upset Xen because it can flush the TLB
itself as needed to maintain its invariants.
When unmapping a region in the vmalloc space, clear the ptes
immediately. There's no point in deferring this because there's no
amortization benefit.
The TLBs are left dirty, and they are flushed lazily to amortize the
cost of the IPIs.
This specific motivation for this patch is an oops-causing regression
since 2.6.36 when using NFS under Xen, triggered by the NFS client's use
of vm_map_ram() introduced in 56e4ebf877b60 ("NFS: readdir with vmapped
pages") . XFS also uses vm_map_ram() and could cause similar problems.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Bryan Schumaker <bjschuma@netapp.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Early after being resumed we need to unplug again the emulated devices.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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When remapping MSIs into pirqs for PV on HVM guests, qemu is responsible
for doing the actual mapping and unmapping.
We only give qemu the desired pirq number when we ask to do the mapping
the first time, after that we should be reading back the pirq number
from qemu every time we want to re-enable the MSI.
This fixes a bug in xen_hvm_setup_msi_irqs that manifests itself when
trying to enable the same MSI for the second time: the old MSI to pirq
mapping is still valid at this point but xen_hvm_setup_msi_irqs would
try to assign a new pirq anyway.
A simple way to reproduce this bug is to assign an MSI capable network
card to a PV on HVM guest, if the user brings down the corresponding
ethernet interface and up again, Linux would fail to enable MSIs on the
device.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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This fixes the same problem as described in the patch "nohz: fix
printk_needs_cpu() return value on offline cpus" for the arch_needs_cpu()
primitive:
arch_needs_cpu() may return 1 if called on offline cpus. When a cpu gets
offlined it schedules the idle process which, before killing its own cpu,
will call tick_nohz_stop_sched_tick().
That function in turn will call arch_needs_cpu() in order to check if the
local tick can be disabled. On offline cpus this function should naturally
return 0 since regardless if the tick gets disabled or not the cpu will be
dead short after. That is besides the fact that __cpu_disable() should already
have made sure that no interrupts on the offlined cpu will be delivered anyway.
In this case it prevents tick_nohz_stop_sched_tick() to call
select_nohz_load_balancer(). No idea if that really is a problem. However what
made me debug this is that on 2.6.32 the function get_nohz_load_balancer() is
used within __mod_timer() to select a cpu on which a timer gets enqueued.
If arch_needs_cpu() returns 1 then the nohz_load_balancer cpu doesn't get
updated when a cpu gets offlined. It may contain the cpu number of an offline
cpu. In turn timers get enqueued on an offline cpu and not very surprisingly
they never expire and cause system hangs.
This has been observed 2.6.32 kernels. On current kernels __mod_timer() uses
get_nohz_timer_target() which doesn't have that problem. However there might
be other problems because of the too early exit tick_nohz_stop_sched_tick()
in case a cpu goes offline.
This specific bug was indrocuded with 3c5d92a0 "nohz: Introduce
arch_needs_cpu".
In this case a cpu hotplug notifier is used to fix the issue in order to keep
the normal/fast path small. All we need to do is to clear the condition that
makes arch_needs_cpu() return 1 since it is just a performance improvement
which is supposed to keep the local tick running for a short period if a cpu
goes idle. Nothing special needs to be done except for clearing the condition.
Cc: stable@kernel.org
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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This follows the ARM change c01778001a4f5ad9c62d882776235f3f31922fdd
("ARM: 6379/1: Assume new page cache pages have dirty D-cache") for the
same rationale:
There are places in Linux where writes to newly allocated page
cache pages happen without a subsequent call to flush_dcache_page()
(several PIO drivers including USB HCD). This patch changes the
meaning of PG_arch_1 to be PG_dcache_clean and always flush the
D-cache for a newly mapped page in update_mmu_cache().
This addresses issues seen with executing binaries from MMC, in
addition to some of the other HCDs that don't explicitly do cache
management for their pipe-in buffers.
Requested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
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for the epson frambuffer support it's CONFIG_FB_S1D13XXX
not CONFIG_FB_S1D135XX
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
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as based on http://www.picotux.com/pt200/picotux200.pdf
these board does not have such I/O
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
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to be a few more concistant with the other boards
as ek is for evaluation kit and dk for development kit
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
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Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
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Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
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Convert the following AT91RM9200-based boards to the new-style UART
initialization:
- Ajeco 1ARM Single Board Computer
- Sperry-Sun KAFA board
- picotux 200
Remove the deprecated at91_init_serial
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Andrew Victor <linux@maxim.org.za>
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Currently, the kprobes implementation for ARM only supports the ARM
instruction set, so it only works if CONFIG_THUMB2_KERNEL is not
enabled.
Until kprobes is updated to work with Thumb-2, turning it on will
cause horrible things to happen, so this patch disables it for now.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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CONFIG_THUMB2_KERNEL
Directives such as .long and .word do not magically cause the
assembler location counter to become aligned in gas. As a
result, using these directives in code sections can result in
misaligned data words when building a Thumb-2 kernel
(CONFIG_THUMB2_KERNEL).
This is a Bad Thing, since the ABI permits the compiler to
assume that fundamental types of word size or above are word-
aligned when accessing them from C. If the data is not really
word-aligned, this can cause impaired performance and stray
alignment faults in some circumstances.
In general, the following rules should be applied when using
data word declaration directives inside code sections:
* .quad and .double:
.align 3
* .long, .word, .single, .float:
.align (or .align 2)
* .short:
No explicit alignment required, since Thumb-2
instructions are always 2 or 4 bytes in size.
immediately after an instruction.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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CONFIG_THUMB2_KERNEL
Directives such as .long and .word do not magically cause the
assembler location counter to become aligned in gas. As a result,
using these directives in code sections can result in misaligned data
words when building a Thumb-2 kernel (CONFIG_THUMB2_KERNEL).
This is a Bad Thing, since the ABI permits the compiler to assume that
fundamental types of word size or above are word- aligned when
accessing them from C. If the data is not really word-aligned, this
can cause impaired performance and stray alignment faults in some
circumstances.
In general, the following rules should be applied when using data word
declaration directives inside code sections:
* .quad and .double:
.align 3
* .long, .word, .single, .float:
.align (or .align 2)
* .short:
No explicit alignment required, since Thumb-2
instructions are always 2 or 4 bytes in size.
immediately after an instruction.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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