Commit Graph

232261 Commits

Author SHA1 Message Date
Thomas Gleixner 30139785e6 cris: Use generic irq Kconfig
Use the generic irq Kconfig. Select GENERIC_HARDIRQS_NO_DEPRECATED as
we have converted all irq_chip functions. Fix the fallout in
show_interrupts().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mikael Starvik <starvik@axis.com>
2011-01-21 11:55:25 +01:00
Thomas Gleixner 9af7503dbd cris: Convert V32 interrupt handling
Convert the irq chip functions and install handle_simple_irq for each
interrupt to get rid of __do_IRQ()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mikael Starvik <starvik@axis.com>
2011-01-21 11:55:25 +01:00
Thomas Gleixner f7a004baa2 cris: Convert V10 interrupt handling
Convert the irq_chip functions and install handle_simple_irq for each
interrupt. This converts V10 to the flow handling and lets us remove
__do_IRQ().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mikael Starvik <starvik@axis.com>
2011-01-21 11:55:25 +01:00
Thomas Gleixner c84077ac29 cris: Use irq handling wrapper
Use the wrapper around __do_IRQ() so we can convert V10 and V32
seperately.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mikael Starvik <starvik@axis.com>
2011-01-21 11:55:24 +01:00
Thomas Gleixner 51f3f15945 h8300: Use generic irq Kconfig
Switch to the generic irq Kconfig. h8300 has all irq chips converted
to the new functions, so select the GENERIC_HARDIRQS_NO_DEPRECATED
switch as well. Fixup the resulting fallout in show_interrupts().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Paul Mundt <lethal@linux-sh.org>
2011-01-21 11:55:24 +01:00
Thomas Gleixner f9f91ef5e3 h8300: Convert interrupt handling to flow handler
__do_IRQ is deprecated so h8300 needs to be converted to proper flow
handling. The irq chip is simple and does not required any
mask/ack/eoi functions, so we can use handle_simple_irq.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Paul Mundt <lethal@linux-sh.org>
2011-01-21 11:55:24 +01:00
Thomas Gleixner 12174aac37 h8300: Convert to new irq_chip functions
No functional change, just straight forward conversion.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Paul Mundt <lethal@linux-sh.org>
2011-01-21 11:55:23 +01:00
Takashi Iwai 842a209700 Merge branch 'fix/asoc' into for-linus 2011-01-21 08:10:14 +01:00
Takashi Iwai 2f36f5e1ff Merge branch 'fix/misc' into for-linus 2011-01-21 08:10:09 +01:00
Scott Wood 8bfc5e3661 powerpc/mpic: Fix mask/unmask timeout message
Don't say that enable timed out when it was disable, and
show which IRQ had the problem.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:39 +11:00
Nishanth Aravamudan cb046de758 powerpc/pseries: Add BNX2=m to defconfig
Upcoming servers will include a Broadcom NIC, add to the defconfig to
increase testing coverage and make sure mainline builds come up with
networking.

Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:39 +11:00
Anton Blanchard ef4f7c2d07 powerpc: Enable 64kB pages and 1024 threads in pseries config
- Enable 64kB pages so it gets some regular testing.

- The largest POWER7 has 1024 threads so bump NR_CPUS it to match.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:39 +11:00
Anton Blanchard 7d2dcd046d powerpc: Disable mcount tracers in pseries defconfig
IRQSOFF_TRACER and STACK_TRACER force the kernel to be built with -pg
which is a substantial overhead.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:39 +11:00
Ben Hutchings 4d9ef89dee powerpc/boot/dts: Install dts from the right directory
The dts-installed variable is initialised using a wildcard path that
will be expanded relative to the build directory.  Use the existing
variable dtstree to generate an absolute wildcard path that will work
when building in a separate directory.

Reported-by: Gerhard Pircher <gerhard_pircher@gmx.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Tested-by: Gerhard Pircher <gerhard_pircher@gmx.net> [against 2.6.32]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:38 +11:00
Anton Blanchard fbe754ca3a powerpc: machine_check_generic is wrong on 64bit
Decoding machine checks is CPU specific and so machine_check_generic doesn't
do the right thing on 64bit chips. Luckily we never call into this code
because we call ppc_md.machine_check_exception instead if available.

Since we check cur_cpu_spec->machine_check before calling it, we may as
well remove machine_check_generic from 64bit archs.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:38 +11:00
Anton Blanchard 7f32c9c600 powerpc: Check RTAS extended log flag before checking length
The spec suggests we should first check the extended log flag before checking
the length field.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:38 +11:00
Anton Blanchard d368514c30 powerpc: Fix corruption when grabbing FWNMI data
The FWNMI code uses a global buffer without any locks to read the RTAS error
information. If two CPUs take a machine check at once then we will corrupt
this buffer.

Since most FWNMI rtas messages are not of the extended type, we can create a
64bit percpu buffer and use it where possible. If we do receive an extended
RTAS log then we fall back to the old behaviour of using the global buffer.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:38 +11:00
Anton Blanchard d47d1d8af5 powerpc: Rework pseries machine check handler
Rework pseries machine check handler:

- If MSR_RI isn't set, we cannot recover even if the machine check was fully
  recovered

- Rename nonfatal to recovered

- Handle RTAS_DISP_LIMITED_RECOVERY

- Use BUS_MCEERR_AR instead of BUS_ADRERR

- Don't check all the RTAS error log fields when receiving a synchronous
  machine check. Recent versions of the pseries firmware do not fill them
  in during a machine check and instead send a follow up error log with
  the detailed information. If we see a synchronous machine check, and we
  came from userspace then kill the task.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:38 +11:00
Anton Blanchard e49b1fae0b powerpc: Don't silently handle machine checks from userspace
If a machine check comes from userspace we send a SIGBUS to the task and
fail to printk anything.

If we are taking machine checks due to bad hardware we want to know about
it right away. Furthermore if we don't complain loudly then it will look
a lot like a bug in the userspace application, potentially causing a lot
of confusion.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:37 +11:00
Anton Blanchard dfb5509f8f powerpc: Remove duplicate debugger hook in machine_check_exception
We are calling debugger_fault_handler twice in machine_check_exception.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:37 +11:00
Anton Blanchard 3f9793e6b6 powerpc: Never halt RTAS error logging after receiving an unrecoverable machine check
Newer versions of the System p firwmare send a partial RTAS error log in the
machine check handler with a more detailed response appearing sometime later
via check event.

This means at machine check time we do not have enough information to
ascertain exactly what went on. Furthermore, I have found the RTAS error
logs in the machine check handler contain no useful information, so halting on
them makes little sense. If we want to halt it would make more sense to do
it following the error log received sometime later via check event.

In light of this, never halt the error log in the pseries machine
check handler.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:37 +11:00
Anton Blanchard a443506b85 powerpc: Don't force MSR_RI in machine_check_exception
We should never force MSR_RI on. If we take a machine check with MSR_RI off
then we have no chance of recovering safely.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:37 +11:00
Anton Blanchard 7071854bb2 powerpc: Print 32 bits of DSISR in show_regs
We were printing 64 bits of DSISR in show_regs even though it is 32 bit.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:37 +11:00
Anton Blanchard ac4414e4d3 powerpc/kdump: Disable ftrace during kexec
We should disable ftrace during kexec, some of the tracers are very invasive
and we do not want them going off while doing the low level work of swapping
one kernel out for another. This mirrors what we do on x86.

Even though we cannot return from a kexec on powerpc (since we do not implement
CONFIG_KEXEC_JUMP), add the restore code in case we do one day.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:36 +11:00
Anton Blanchard 158d5b5e36 powerpc/kdump: Move crash_kexec_stop_spus to kdump crash handler
Use the crash handler hooks to run the SPU stop code, just like we do for
ehea and cell RAS code.

While I'm here I noticed "CPUSs reliabally"

so fix the spelling MISTAKESs reliabally.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:36 +11:00
Anton Blanchard c6baabfb84 powerpc/kexec: Remove empty ppc_md.machine_kexec_prepare
We check for a valid handler before calling ppc_md.machine_kexec_prepare
so we can just remove these empty handlers.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:36 +11:00
Anton Blanchard 2bb44d628c powerpc/kexec: Don't initialise kexec hooks to default handlers
There's no need to initialise ppc_md.machine_kexec and
ppc_md.machine_kexec_prepare to the default handlers.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:35 +11:00
Anton Blanchard c1f784e553 powerpc/kdump: Remove ppc_md.machine_crash_shutdown
No one uses ppc_md.machine_crash_shutdown, so remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:35 +11:00
Anton Blanchard c94868788c powerpc/kexec: Remove ppc_md.machine_kexec
No one uses ppc_md.machine_kexec, so remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:35 +11:00
Anton Blanchard 619b267724 powerpc/kexec: Remove ppc_md.machine_kexec_cleanup
No one uses ppc_md.machine_kexec_cleanup, so remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:35 +11:00
Anton Blanchard 50266a1f8a powerpc/kexec: Move all ppc_md kexec function pointers together
Move all the kexec handlers together.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:34 +11:00
Tejun Heo b18ae08dea powerpc/cell: Use system_wq in cpufreq_spudemand
With cmwq, there's no reason to use a separate workqueue in
cpufreq_spudemand.  Use system_wq instead.  The work items are already
sync canceled on stop, so it's already guaranteed that no work is
running when spu_gov_exit() is entered.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Dave Jones <davej@redhat.com>
Cc: cpufreq@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:34 +11:00
roel kluin f32be0c540 powerpc/macintosh: Fix wrong test in fan_{read,write}_reg()
Fix error test in fan_{read,write}_reg()

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:34 +11:00
Akinobu Mita 4c4a5cf64b powerpc/rtas_flash: Use simple_read_from_buffer
Simplify read file operation for /proc/powerpc/rtas/* interface
by using simple_read_from_buffer.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:34 +11:00
Akinobu Mita 63c3b9d71b powerpc/spufs: Use simple_write_to_buffer
Simplify several write fileoperations for spufs by using
simple_write_to_buffer().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:34 +11:00
Steven Rostedt 06ca2188ec powerpc/ppc32/tracing: Add stack frame to calls of trace_hardirqs_on/off
32-bit variant of the previous patch for 64-bit:

<<
    When an interrupt occurs in userspace, we can call trace_hardirqs_on/off()
    With one level stack. But if we have irqsoff tracing enabled,
    it checks both CALLER_ADDR0 and CALLER_ADDR1. The second call
    goes two stack frames up. If this is from user space, then there may
    not exist a second stack....
>>

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:33 +11:00
Steven Rostedt 3cb5f1a3e5 powerpc/ppc64/tracing: Add stack frame to calls of trace_hardirqs_on/off
When an interrupt occurs in userspace, we can call trace_hardirqs_on/off()
    With one level stack. But if we have irqsoff tracing enabled,
    it checks both CALLER_ADDR0 and CALLER_ADDR1. The second call
    goes two stack frames up. If this is from user space, then there may
    not exist a second stack.

    Add a second stack when calling trace_hardirqs_on/off() otherwise
    the following oops might occur:

    Oops: Kernel access of bad area, sig: 11 [#1]
    PREEMPT SMP NR_CPUS=2 PA Semi PWRficient
    last sysfs file: /sys/block/sda/size
    Modules linked in: ohci_hcd ehci_hcd usbcore
    NIP: c0000000000e1c00 LR: c0000000000034d4 CTR: 000000011012c440
    REGS: c00000003e2f3af0 TRAP: 0300   Not tainted  (2.6.37-rc6+)
    MSR: 9000000000001032 <ME,IR,DR>  CR: 48044444  XER: 20000000
    DAR: 00000001ffb9db50, DSISR: 0000000040000000
    TASK = c00000003e1a00a0[2088] 'emacs' THREAD: c00000003e2f0000 CPU: 1
    GPR00: 0000000000000001 c00000003e2f3d70 c00000000084e0d0 c0000000008816e8
    GPR04: 000000001034c678 000000001032e8f9 0000000010336540 0000000040020000
    GPR08: 0000000040020000 00000001ffb9db40 c00000003e2f3e30 0000000060000000
    GPR12: 100000000000f032 c00000000fff0280 000000001032e8c9 0000000000000008
    GPR16: 00000000105be9c0 00000000105be950 00000000105be9b0 00000000105be950
    GPR20: 00000000ffb9dc50 00000000ffb9dbf0 00000000102f0000 00000000102f0000
    GPR24: 00000000102e0000 00000000102f0000 0000000010336540 c0000000009ded38
    GPR28: 00000000102e0000 c0000000000034d4 c0000000007ccb10 c00000003e2f3d70
    NIP [c0000000000e1c00] .trace_hardirqs_off+0xb0/0x1d0
    LR [c0000000000034d4] decrementer_common+0xd4/0x100
    Call Trace:
    [c00000003e2f3d70] [c00000003e2f3e30] 0xc00000003e2f3e30 (unreliable)
    [c00000003e2f3e30] [c0000000000034d4] decrementer_common+0xd4/0x100
    Instruction dump:
    81690000 7f8b0000 419e0018 f84a0028 60000000 60000000 60000000 e95f0000
    80030000 e92a0000 eb6301f8 2f800000 <eb890010> 41fe00dc a06d000a eb1e8050
    ---[ end trace 4ec7fd2be9240928 ]---

    Reported-by: Joerg Sommer <joerg@alea.gnuu.de>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:33 +11:00
Michael Ellerman c0337288ab powerpc: Ensure the else case of feature sections will fit
When we create an alternative feature section, the else case must be the
same size or smaller than the body. This is because when we patch the
else case in we just overwrite the body, so there must be room.

Up to now we just did this by inspection, but it's quite easy to enforce
it in the assembler, so we should.

The only change is to add the ifgt block, but that effects the alignment
of the tabs and so the whole macro is modified.

Also add a test, but #if 0 it because we don't want to break the build.
Anyone who's modifying the feature macros should enable the test.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-01-21 14:08:33 +11:00
Linus Torvalds 2b1caf6ed7 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  smp: Allow on_each_cpu() to be called while early_boot_irqs_disabled status to init/main.c
  lockdep: Move early boot local IRQ enable/disable status to init/main.c
2011-01-20 18:30:37 -08:00
Rafael J. Wysocki d551d81d6a ACPI / PM: Call suspend_nvs_free() earlier during resume
It turns out that some device drivers map pages from the ACPI NVS region
during resume using ioremap(), which conflicts with ioremap_cache() used
for mapping those pages by the NVS save/restore code in nvs.c.

Make the NVS pages mapped by the code in nvs.c be unmapped before device
drivers' resume routines run.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 18:30:17 -08:00
Rafael J. Wysocki 2d6d9fd3a5 ACPI: Introduce acpi_os_ioremap()
Commit ca9b600be3 ("ACPI / PM: Make suspend_nvs_save() use
acpi_os_map_memory()") attempted to prevent the code in osl.c and nvs.c
from using different ioremap() variants by making the latter use
acpi_os_map_memory() for mapping the NVS pages.  However, that also
requires acpi_os_unmap_memory() to be used for unmapping them, which
causes synchronize_rcu() to be executed many times in a row
unnecessarily and introduces substantial delays during resume on some
systems.

Instead of using acpi_os_map_memory() for mapping the NVS pages in nvs.c
introduce acpi_os_ioremap() calling ioremap_cache() and make the code in
both osl.c and nvs.c use it.

Reported-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 18:30:17 -08:00
Jeff Layton 99d86c8f1b cifs: fix up CIFSSMBEcho for unaligned access
Make sure that CIFSSMBEcho can handle unaligned fields. Also fix a minor
bug that causes this warning:

fs/cifs/cifssmb.c: In function 'CIFSSMBEcho':
fs/cifs/cifssmb.c:740: warning: large integer implicitly truncated to unsigned type

...WordCount is u8, not __le16, so no need to convert it.

This patch should apply cleanly on top of the rest of the patchset to
clean up unaligned access.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2011-01-21 02:23:27 +00:00
Steve French bf67b9be97 Merge branch 'for-next' 2011-01-21 02:19:30 +00:00
Linus Torvalds 8d99641f6c Merge branch 'akpm'
* akpm:
  kernel/smp.c: consolidate writes in smp_call_function_interrupt()
  kernel/smp.c: fix smp_call_function_many() SMP race
  memcg: correctly order reading PCG_USED and pc->mem_cgroup
  backlight: fix 88pm860x_bl macro collision
  drivers/leds/ledtrig-gpio.c: make output match input, tighten input checking
  MAINTAINERS: update Atmel AT91 entry
  mm: fix truncate_setsize() comment
  memcg: fix rmdir, force_empty with THP
  memcg: fix LRU accounting with THP
  memcg: fix USED bit handling at uncharge in THP
  memcg: modify accounting function for supporting THP better
  fs/direct-io.c: don't try to allocate more than BIO_MAX_PAGES in a bio
  mm: compaction: prevent division-by-zero during user-requested compaction
  mm/vmscan.c: remove duplicate include of compaction.h
  memblock: fix memblock_is_region_memory()
  thp: keep highpte mapped until it is no longer needed
  kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT
2011-01-20 17:02:14 -08:00
Milton Miller 225c8e010f kernel/smp.c: consolidate writes in smp_call_function_interrupt()
We have to test the cpu mask in the interrupt handler before checking the
refs, otherwise we can start to follow an entry before its deleted and
find it partially initailzed for the next trip.  Presently we also clear
the cpumask bit before executing the called function, which implies
getting write access to the line.  After the function is called we then
decrement refs, and if they go to zero we then unlock the structure.

However, this implies getting write access to the call function data
before and after another the function is called.  If we can assert that no
smp_call_function execution function is allowed to enable interrupts, then
we can move both writes to after the function is called, hopfully allowing
both writes with one cache line bounce.

On a 256 thread system with a kernel compiled for 1024 threads, the time
to execute testcase in the "smp_call_function_many race" changelog was
reduced by about 30-40ms out of about 545 ms.

I decided to keep this as WARN because its now a buggy function, even
though the stack trace is of no value -- a simple printk would give us the
information needed.

Raw data:

Without patch:
  ipi_test startup took 1219366ns complete 539819014ns total 541038380ns
  ipi_test startup took 1695754ns complete 543439872ns total 545135626ns
  ipi_test startup took 7513568ns complete 539606362ns total 547119930ns
  ipi_test startup took 13304064ns complete 533898562ns total 547202626ns
  ipi_test startup took 8668192ns complete 544264074ns total 552932266ns
  ipi_test startup took 4977626ns complete 548862684ns total 553840310ns
  ipi_test startup took 2144486ns complete 541292318ns total 543436804ns
  ipi_test startup took 21245824ns complete 530280180ns total 551526004ns

With patch:
  ipi_test startup took 5961748ns complete 500859628ns total 506821376ns
  ipi_test startup took 8975996ns complete 495098924ns total 504074920ns
  ipi_test startup took 19797750ns complete 492204740ns total 512002490ns
  ipi_test startup took 14824796ns complete 487495878ns total 502320674ns
  ipi_test startup took 11514882ns complete 494439372ns total 505954254ns
  ipi_test startup took 8288084ns complete 502570774ns total 510858858ns
  ipi_test startup took 6789954ns complete 493388112ns total 500178066ns

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/sched.h> /* sched clock */

	#define ITERATIONS 100

	static void do_nothing_ipi(void *dummy)
	{
	}

	static void do_ipis(struct work_struct *dummy)
	{
		int i;

		for (i = 0; i < ITERATIONS; i++)
			smp_call_function(do_nothing_ipi, NULL, 1);

		printk(KERN_DEBUG "cpu %d finished\n", smp_processor_id());
	}

	static struct work_struct work[NR_CPUS];

	static int __init testcase_init(void)
	{
		int cpu;
		u64 start, started, done;

		start = local_clock();
		for_each_online_cpu(cpu) {
			INIT_WORK(&work[cpu], do_ipis);
			schedule_work_on(cpu, &work[cpu]);
		}
		started = local_clock();
		for_each_online_cpu(cpu)
			flush_work(&work[cpu]);
		done = local_clock();
		pr_info("ipi_test startup took %lldns complete %lldns total %lldns\n",
			started-start, done-started, done-start);

		return 0;
	}

	static void __exit testcase_exit(void)
	{
	}

	module_init(testcase_init)
	module_exit(testcase_exit)
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Anton Blanchard");

Signed-off-by: Milton Miller <miltonm@bga.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:06 -08:00
Anton Blanchard 6dc1989995 kernel/smp.c: fix smp_call_function_many() SMP race
I noticed a failure where we hit the following WARN_ON in
generic_smp_call_function_interrupt:

                if (!cpumask_test_and_clear_cpu(cpu, data->cpumask))
                        continue;

                data->csd.func(data->csd.info);

                refs = atomic_dec_return(&data->refs);
                WARN_ON(refs < 0);      <-------------------------

We atomically tested and cleared our bit in the cpumask, and yet the
number of cpus left (ie refs) was 0.  How can this be?

It turns out commit 54fdade1c3
("generic-ipi: make struct call_function_data lockless") is at fault.  It
removes locking from smp_call_function_many and in doing so creates a
rather complicated race.

The problem comes about because:

 - The smp_call_function_many interrupt handler walks call_function.queue
   without any locking.
 - We reuse a percpu data structure in smp_call_function_many.
 - We do not wait for any RCU grace period before starting the next
   smp_call_function_many.

Imagine a scenario where CPU A does two smp_call_functions back to back,
and CPU B does an smp_call_function in between.  We concentrate on how CPU
C handles the calls:

CPU A            CPU B                  CPU C              CPU D

smp_call_function
                                        smp_call_function_interrupt
                                            walks
					call_function.queue sees
					data from CPU A on list

                 smp_call_function

                                        smp_call_function_interrupt
                                            walks

                                        call_function.queue sees
                                          (stale) CPU A on list
							   smp_call_function int
							   clears last ref on A
							   list_del_rcu, unlock
smp_call_function reuses
percpu *data A
                                         data->cpumask sees and
                                         clears bit in cpumask
                                         might be using old or new fn!
                                         decrements refs below 0

set data->refs (too late!)

The important thing to note is since the interrupt handler walks a
potentially stale call_function.queue without any locking, then another
cpu can view the percpu *data structure at any time, even when the owner
is in the process of initialising it.

The following test case hits the WARN_ON 100% of the time on my PowerPC
box (having 128 threads does help :)

#include <linux/module.h>
#include <linux/init.h>

#define ITERATIONS 100

static void do_nothing_ipi(void *dummy)
{
}

static void do_ipis(struct work_struct *dummy)
{
	int i;

	for (i = 0; i < ITERATIONS; i++)
		smp_call_function(do_nothing_ipi, NULL, 1);

	printk(KERN_DEBUG "cpu %d finished\n", smp_processor_id());
}

static struct work_struct work[NR_CPUS];

static int __init testcase_init(void)
{
	int cpu;

	for_each_online_cpu(cpu) {
		INIT_WORK(&work[cpu], do_ipis);
		schedule_work_on(cpu, &work[cpu]);
	}

	return 0;
}

static void __exit testcase_exit(void)
{
}

module_init(testcase_init)
module_exit(testcase_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Anton Blanchard");

I tried to fix it by ordering the read and the write of ->cpumask and
->refs.  In doing so I missed a critical case but Paul McKenney was able
to spot my bug thankfully :) To ensure we arent viewing previous
iterations the interrupt handler needs to read ->refs then ->cpumask then
->refs _again_.

Thanks to Milton Miller and Paul McKenney for helping to debug this issue.

[miltonm@bga.com: add WARN_ON and BUG_ON, remove extra read of refs before initial read of mask that doesn't help (also noted by Peter Zijlstra), adjust comments, hopefully clarify scenario ]
[miltonm@bga.com: remove excess tests]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Milton Miller <miltonm@bga.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: <stable@kernel.org> [2.6.32+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:06 -08:00
Johannes Weiner 713735b423 memcg: correctly order reading PCG_USED and pc->mem_cgroup
The placement of the read-side barrier is confused: the writer first
sets pc->mem_cgroup, then PCG_USED.  The read-side barrier has to be
between testing PCG_USED and reading pc->mem_cgroup.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:06 -08:00
Randy Dunlap 2550326ac7 backlight: fix 88pm860x_bl macro collision
Fix collision with kernel-supplied #define:

  drivers/video/backlight/88pm860x_bl.c:24:1: warning: "CURRENT_MASK" redefined
  arch/x86/include/asm/page_64_types.h:6:1: warning: this is the location of the previous definition

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Haojian Zhuang <haojian.zhuang@marvell.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:06 -08:00
Janusz Krzysztofik cc587ece12 drivers/leds/ledtrig-gpio.c: make output match input, tighten input checking
Replicate changes made to drivers/leds/ledtrig-backlight.c.

Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:06 -08:00
Nicolas Ferre c1fc8675c9 MAINTAINERS: update Atmel AT91 entry
Add two co-maintainers and update the entry with new information.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:06 -08:00