x86/mm: do not trigger a kernel warning if user-space disables interrupts and generates a page fault

Arjan reported a spike in the following bug pattern in v2.6.27:

   http://www.kerneloops.org/searchweek.php?search=lock_page

which happens because hwclock started triggering warnings due to
a (correct) might_sleep() check in the MM code.

The warning occurs because hwclock uses this dubious sequence of
code to run "atomic" code:

  static unsigned long
  atomic(const char *name, unsigned long (*op)(unsigned long),
         unsigned long arg)
  {
    unsigned long v;
    __asm__ volatile ("cli");
    v = (*op)(arg);
    __asm__ volatile ("sti");
    return v;
  }

Then it pagefaults in that "atomic" section, triggering the warning.

There is no way the kernel could provide "atomicity" in this path,
a page fault is a cannot-continue machine event so the kernel has to
wait for the page to be filled in.

Even if it was just a minor fault we'd have to take locks and might have
to spend quite a bit of time with interrupts disabled - not nice to irq
latencies in general.

So instead just enable interrupts in the pagefault path unconditionally
if we come from user-space, and handle the fault.

Also, while touching this code, unify some trivial parts of the x86
VM paths at the same time.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Remove ending ':' from some of the Topic lines for consistency.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add F: definition since it is being used.

Expand acronyms or add them so that users of MAINTAINERS file can find
entries more easily.

Correct driver spelling.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Sorted case-insensitive (sort -f).
Groups that begin with ARM, INTEL, etc. not sorted.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix kconfig typo and extra whitespace
  ext4: fix build failure without procfs
  ext4: add an option to control error handling on file data
  jbd2: don't dirty original metadata buffer on abort
  ext4: add checks for errors from jbd2
  jbd2: fix error handling for checkpoint io
  jbd2: abort when failed to log metadata buffers

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/super.c: In function 'ext4_fill_super':
fs/ext4/super.c:2226: error: 'ext4_ui_proc_fops' undeclared (first use
in this function)
fs/ext4/super.c:2226: error: (Each undeclared identifier is reported
only once
fs/ext4/super.c:2226: error: for each function it appears in.)
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  [CIFS] cifs: remove pointless lock and unlock of GlobalMid_Lock in header_assemble

It needs the WM97xx touchscreen driver to be compiled in, not as a
module.  And it cannot itself be a module, due to some unfortunate
interactions with platform data.
Reported-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'x86-core-v2-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

This merges in:

  x86/build, x86/microcode, x86/spinlocks, x86/memory-corruption-check,
  x86/early-printk, x86/xsave, x86/quirks, x86/setup, x86/signal,
  core/signal, x86/urgent, x86/xen

* 'x86-core-v2-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (142 commits)
  x86: make processor type select depend on CONFIG_EMBEDDED
  x86: extend processor type select help text
  x86, amd-iommu: propagate PCI device enabling error
  warnings: fix arch/x86/kernel/io_apic_64.c
  warnings: fix arch/x86/kernel/early_printk.c
  x86, fpu: check __clear_user() return value
  x86: memory corruption check - cleanup
  x86: ioperm user_regset
  xen: do not reserve 2 pages of padding between hypervisor and fixmap.
  xen: use spin_lock_nest_lock when pinning a pagetable
  x86: xsave: set FP, SSE bits in the xsave header in the user sigcontext
  x86: xsave: fix error condition in save_i387_xstate()
  x86: SB450: deprioritize DMI quirks
  x86: SB450: skip IRQ0 override if it is not routed to INT2 of IOAPIC
  x86: replace a magic number with a named constant in the VESA boot code
  x86 setup: remove IMAGE_OFFSET
  x86 setup: remove DEF_INITSEG and DEF_SETUPSEG
  Revert "x86: fix ghost EDD devices in /sys again"
  x86 setup: fix ghost entries under /sys/firmware/edd take 3
  x86: signal: remove indent in restore_sigcontext()
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/hskinnemoen/avr32-2.6:
  avr32: Fix build failures in board code
  avr32: Allow selecting multiple pins at once
  avr32: Minor pm_power_off cleanup
  avr32: Implement {read,write}[bwl]_be
  avr32: Replace static clock list with dynamic linked list
  avr32: Use platform_driver_probe for pdc platform driver
  avr32: Use platform_driver_probe for pio platform driver
  avr32: Provide a way to deselect pins in the portmux
  ngw100: export J15 through sysfs
  avr32: Allow fine-grained control over LCDC pins
  avr32: added mem kernel command line option support
  Add kernel support for oprofile callgraphs on AVR32
  avr32: use the new byteorder headers

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/drzeus/mmc: (24 commits)
  MMC: Use timeout values from CSR
  MMC: CSD and CID timeout values
  sdhci: 'scratch' may be used uninitialized
  mmc: explicitly mention SDIO support in Kconfig
  mmc: remove redundant "depends on"
  Fix comment in include/linux/mmc/host.h
  sdio: high-speed support
  mmc_block: hard code 512 byte block size
  sdhci: force high speed capability on some controllers
  mmc_block: filter out PC requests
  mmc_block: indicate strict ordering
  mmc_block: inform block layer about sector count restriction
  sdio: give sdio irq thread a host specific name
  sdio: make sleep on error interruptable
  sdhci: reduce card detection delay
  sdhci: let the controller wait for busy state to end
  atmel-mci: Add missing flush_dcache_page() in PIO transfer code
  atmel-mci: Don't overwrite error bits when NOTBUSY is set
  atmel-mci: Add experimental DMA support
  atmel-mci: support multiple mmc slots
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
  [WATCHDOG] orion5x_wdt.c: add spinlocking
  [WATCHDOG] Orion: add hardware watchdog support
  [WATCHDOG] omap_wdt.c: cleanup a bit omap_wdt.c
  [WATCHDOG] omap_wdt.c: another ioremap() fix
  [WATCHDOG] omap_wdt.c: sync linux-omap changes
  [WATCHDOG] Add AT91SAM9X watchdog
  [WATCHDOG] Add driver for winbond w83697ug/uf watchdog feature
  [WATCHDOG] add watchdog driver IT8716 IT8726 IT8712J/K

Merge branch 'x86-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: fix early panic on amd64 due to typo in supported CPU section
  x86, early_ioremap: fix fencepost error
  x86: avoid dereferencing beyond stack + THREAD_SIZE

This fixes the following compile error with CONFIG_BLOCK=n caused by
commit 68c9d702 ("generic block based
fiemap implementation"):

    CC      fs/ioctl.o
  fs/ioctl.c: In function 'generic_block_fiemap':
  fs/ioctl.c:249: error: storage size of 'tmp' isn't known
  fs/ioctl.c:272: error: invalid application of 'sizeof' to incomplete type 'struct buffer_head'
  fs/ioctl.c:280: error: implicit declaration of function 'buffer_mapped'
  fs/ioctl.c:249: warning: unused variable 'tmp'
  make[2]: *** [fs/ioctl.o] Error 1
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This fixes the following build error with CONFIG_KEYS=n, caused by
commit dfd15c46 ("cifs: explicitly
revoke SPNEGO key after session setup"):

    CC [M]  fs/cifs/sess.o
  fs/cifs/sess.c: In function 'CIFS_SessSetup':
  fs/cifs/sess.c:628: error: implicit declaration of function 'key_revoke'
  make[3]: *** [fs/cifs/sess.o] Error 1
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next-2.6: (180 commits)
  leo: disable cursor when leaving graphics mode
  cg6: disable cursor when leaving graphics mode
  sparc32: sun4m interrupt mask cleanup
  drivers/rtc/Kconfig: don't build rtc-cmos.o on sparc32
  sparc: arch/sparc/kernel/pmc.c -- extra #include?
  sparc32: Add more extensive documentation of sun4m interrupts.
  sparc32: Kill irq_rcvreg from sun4m_irq.c
  sparc32: Delete master_l10_limit.
  sparc32: Use PROM device probing for sun4c timers.
  sparc32: Use PROM device probing for sun4c interrupt register.
  sparc32: Delete claim_ticker14().
  sparc32: Stop calling claim_ticker14() from sun4c_irq.c
  sparc32: Kill clear_profile_irq btfixup entry.
  sparc32: Call sun4m_clear_profile_irq() directly from sun4m_smp.c
  sparc32: Remove #if 0'd code from sun4c_irq.c
  sparc32: Remove some SMP ifdefs in sun4d_irq.c
  sparc32: Use PROM infrastructure for probing and mapping sun4d timers.
  sparc32: Use PROM device probing for sun4m irq registers.
  sparc32: Use PROM device probing for sun4m timer registers.
  sparc: Fix user_regset 'n' field values.
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  smc911x: Fix external PHY detection
  e1000: allow VLAN devices to use TSO and CSUM offload
  gre: Initialise rtnl_link tunnel parameters properly
  ipvs: Add proper dependencies on IP_VS, and fix description header line.

Commit ed458df4 ("PnP: move
pnpacpi/pnpbios_init to after PCI init") moved the PnP RTC discovery
later, and now the ACPI RTC glue code doesn't find it any more, breaking
the RTC wakealarm sysfs interfaces, as reported by Rafael.

This really is fairly messy, and we have several annoying ordering
constraints here - the PnP code that sets up the RTC resources wants to
run after the PCI resources have to be registered, which in turn needs
to run after ACPI has at least enumerated the root PCI buses etc.  Our
initcall ordering is not fine-grained enough to make this all painless.

So this moves the ACPI RTC glue ("acpi_rtc_init()") down to a regular
module call, which fixes the problem Rafael has.  The reason this isn't
wonderful is that we really should do acpi_rtc_init before we do the
rtc_cmos init, and now those two are in the same module_init() section.

Which happens to work, but only because drivers/rtc is linked after
drivers/acpi.  In other words, we still have a very subtle ordering
issue here. Grr.
Reported-and-tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix a few instances of board code breakage introduced by the atmel-mci
platform interface changes.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

at32_select_periph() now takes an u32 bitmask rather than a single pin.
This allows to set multiple pins at once.
Signed-off-by: Alex Raimondi <mailinglist@miromico.ch>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

Merge branches 'x86/xen', 'x86/build', 'x86/microcode', 'x86/mm-debug-v2', 'x86/memory-corruption-check', 'x86/early-printk', 'x86/xsave', 'x86/ptrace-v2', 'x86/quirks', 'x86/setup', 'x86/spinlocks' and 'x86/signal' into x86/core-v2

deselecting one of the CPU type CONFIG_CPU_SUP_* config options
can render a kernel unbootable. Make sure this option is only
available if CONFIG_EMBEDDED is enabled.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

extend the help text of the CONFIG_CPU_SUP_* config options to
express what it does and what effects it has.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

We lock GlobalMid_Lock in header_assemble and then immediately unlock it
again without doing anything. Not sure what this was intended to do, but
remove it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

propagate an error in enabling the PCI device.

Also eliminates this warning:

 arch/x86/kernel/amd_iommu_init.c: In function ‘init_iommu_one’:
 arch/x86/kernel/amd_iommu_init.c:726: warning: ignoring return value of ‘pci_enable_device’, declared with attribute warn_unused_result
Signed-off-by: Ingo Molnar <mingo@elte.hu>

fix:

 arch/x86/kernel/io_apic_64.c: In function ‘print_local_APIC’:
 arch/x86/kernel/io_apic_64.c:1284: warning: format ‘%08x’ expects type ‘unsigned int’, but argument 2 has type ‘long unsigned int’
 arch/x86/kernel/io_apic_64.c:1285: warning: format ‘%08x’ expects type ‘unsigned int’, but argument 2 has type ‘long unsigned int’

We want to print the two halves of 'icr' at 32 bit width.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

fix warning:

  arch/x86/kernel/early_printk.c:993: warning: ‘enable_debug_console’ defined but not used

Eliminate dead code.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

fix warning:

  arch/x86/kernel/xsave.c: In function ‘save_i387_xstate’:
  arch/x86/kernel/xsave.c:98: warning: ignoring return value of ‘__clear_user’, declared with attribute warn_unused_result

check the return value and act on it. We should not be ignoring faults
at this point.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Move the prototypes from the generic kernel.h header to the more
appropriate include/asm-x86/bios_ebda.h header file.

Also, remove the check from the power management code - this is a
pure x86 matter for now.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Conflicts:
	include/asm-x86/spinlock.h

Conflicts:
	arch/x86/kernel/signal_64.c

Conflicts:
	arch/x86/kernel/early-quirks.c

Done to prevent this failure of an Octopus merge:

 Added arch/arm/include/asm/byteorder.h in both, but differently.
 ERROR: Merge conflict in arch/arm/include/asm/byteorder.h
 Auto-merging include/asm-x86/spinlock.h
 ERROR: Merge conflict in include/asm-x86/spinlock.h
 fatal: merge program failed

Conflicts:
	arch/x86/kernel/cpu/common.c
	arch/x86/kernel/process_64.c
	arch/x86/xen/enlighten.c

This adds a user_regset type for the x86 io permissions bitmap.
This makes it appear in core dumps (when ioperm has been used).
It will also make it visible to debuggers in the future.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
[conflict resolutions: Signed-off-by: Ingo Molnar <mingo@elte.hu> ]