Commit Graph

764 Commits

Author SHA1 Message Date
Benjamin Herrenschmidt 9be72573a8 powerpc: Add support for page fault retry and fatal signals
Other architectures such as x86 and ARM have been growing
new support for features like retrying page faults after
dropping the mm semaphore to break contention, or being
able to return from a stuck page fault when a SIGKILL is
pending.

This refactors our implementation of do_page_fault() to
move the error handling out of line in a way similar to
x86 and adds support for those two features.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-09 10:55:12 +11:00
Benjamin Herrenschmidt a546498f3b powerpc: Call do_page_fault() with interrupts off
We currently turn interrupts back to their previous state before
calling do_page_fault(). This can be annoying when debugging as
a bad fault will potentially have lost some processor state before
getting into the debugger.

We also end up calling some generic code with interrupts enabled
such as notify_page_fault() with interrupts enabled, which could
be unexpected.

This changes our code to behave more like other architectures,
and make the assembly entry code call into do_page_faults() with
interrupts disabled. They are conditionally re-enabled from
within do_page_fault() in the same spot x86 does it.

While there, add the might_sleep() test in the case of a successful
trylock of the mmap semaphore, again like x86.

Also fix a bug in the existing assembly where r12 (_MSR) could get
clobbered by C calls (the DTL accounting in the exception common
macro and DISABLE_INTS) in some cases.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

v2. Add the r12 clobber fix
2012-03-09 10:55:08 +11:00
Benjamin Herrenschmidt 4f8cf36f48 powerpc: Remove legacy iSeries bits from assembly files
This removes the various bits of assembly in the kernel entry,
exception handling and SLB management code that were specific
to running under the legacy iSeries hypervisor which is no
longer supported.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-09 10:54:59 +11:00
Joe Perches a2234b4bae powerpc: Use vsprintf extention %pf with builtin_return_address
Emit the function name not the address when possible.

builtin_return_address() gives an address.  When building
a kernel with CONFIG_KALLSYMS, emit the actual function
name not the address.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-07 17:06:09 +11:00
Jimi Xenidis de801de139 powerpc/icswx: Fix race condition with IPI setting ACOP
There is a race where a thread causes a coprocessor type to be valid
in its own ACOP _and_ in the current context, but it does not
propagate to the ACOP register of other threads in time for them to
use it.  The original code tries to solve this by sending an IPI to
all threads on the system, which is heavy handed, but unfortunately
still provides a window where the icswx is issued by other threads and
the ACOP is not up to date.

This patch detects that the ACOP DSI fault was a "false positive" and
syncs the ACOP and causes the icswx to be replayed.

Signed-off-by: Jimi Xenidis <jimix@pobox.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-03-07 17:06:09 +11:00
Mahesh Salgaonkar 3ccc00a7e0 fadump: Register for firmware assisted dump.
On 2012-02-20 11:02:51 Mon, Paul Mackerras wrote:
> On Thu, Feb 16, 2012 at 04:44:30PM +0530, Mahesh J Salgaonkar wrote:
>
> If I have read the code correctly, we are going to get this printk on
> non-pSeries machines or on older pSeries machines, even if the user
> has not put the fadump=on option on the kernel command line.  The
> printk will be annoying since there is no actual error condition.  It
> seems to me that the condition for the printk should include
> fw_dump.fadump_enabled.  In other words you should probably add
>
> 	if (!fw_dump.fadump_enabled)
> 		return 0;
>
> at the beginning of the function.

Hi Paul,

Thanks for pointing it out. Please find the updated patch below.

The existing patches above this (4/10 through 10/10) cleanly applies
on this update.

Thanks,
-Mahesh.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-02-23 10:50:01 +11:00
Wanlong Gao 9512938b88 cpumask: update setup_node_to_cpumask_map() comments
node_to_cpumask() has been replaced by cpumask_of_node(), and wholly
removed since commit 29c337a0 ("cpumask: remove obsolete node_to_cpumask
now everyone uses cpumask_of_node").

So update the comments for setup_node_to_cpumask_map().

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:11 -08:00
Linus Torvalds 98793265b4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits)
  Kconfig: acpi: Fix typo in comment.
  misc latin1 to utf8 conversions
  devres: Fix a typo in devm_kfree comment
  btrfs: free-space-cache.c: remove extra semicolon.
  fat: Spelling s/obsolate/obsolete/g
  SCSI, pmcraid: Fix spelling error in a pmcraid_err() call
  tools/power turbostat: update fields in manpage
  mac80211: drop spelling fix
  types.h: fix comment spelling for 'architectures'
  typo fixes: aera -> area, exntension -> extension
  devices.txt: Fix typo of 'VMware'.
  sis900: Fix enum typo 'sis900_rx_bufer_status'
  decompress_bunzip2: remove invalid vi modeline
  treewide: Fix comment and string typo 'bufer'
  hyper-v: Update MAINTAINERS
  treewide: Fix typos in various parts of the kernel, and fix some comments.
  clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR
  gpio: Kconfig: drop unknown symbol 'CS5535_GPIO'
  leds: Kconfig: Fix typo 'D2NET_V2'
  sound: Kconfig: drop unknown symbol ARCH_CLPS7500
  ...

Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new
kconfig additions, close to removed commented-out old ones)
2012-01-08 13:21:22 -08:00
Linus Torvalds 7affca3537 Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (73 commits)
  arm: fix up some samsung merge sysdev conversion problems
  firmware: Fix an oops on reading fw_priv->fw in sysfs loading file
  Drivers:hv: Fix a bug in vmbus_driver_unregister()
  driver core: remove __must_check from device_create_file
  debugfs: add missing #ifdef HAS_IOMEM
  arm: time.h: remove device.h #include
  driver-core: remove sysdev.h usage.
  clockevents: remove sysdev.h
  arm: convert sysdev_class to a regular subsystem
  arm: leds: convert sysdev_class to a regular subsystem
  kobject: remove kset_find_obj_hinted()
  m86k: gpio - convert sysdev_class to a regular subsystem
  mips: txx9_sram - convert sysdev_class to a regular subsystem
  mips: 7segled - convert sysdev_class to a regular subsystem
  sh: dma - convert sysdev_class to a regular subsystem
  sh: intc - convert sysdev_class to a regular subsystem
  power: suspend - convert sysdev_class to a regular subsystem
  power: qe_ic - convert sysdev_class to a regular subsystem
  power: cmm - convert sysdev_class to a regular subsystem
  s390: time - convert sysdev_class to a regular subsystem
  ...

Fix up conflicts with 'struct sysdev' removal from various platform
drivers that got changed:
 - arch/arm/mach-exynos/cpu.c
 - arch/arm/mach-exynos/irq-eint.c
 - arch/arm/mach-s3c64xx/common.c
 - arch/arm/mach-s3c64xx/cpu.c
 - arch/arm/mach-s5p64x0/cpu.c
 - arch/arm/mach-s5pv210/common.c
 - arch/arm/plat-samsung/include/plat/cpu.h
 - arch/powerpc/kernel/sysfs.c
and fix up cpu_is_hotpluggable() as per Greg in include/linux/cpu.h
2012-01-07 12:03:30 -08:00
Linus Torvalds e4e88f31bc Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (185 commits)
  powerpc: fix compile error with 85xx/p1010rdb.c
  powerpc: fix compile error with 85xx/p1023_rds.c
  powerpc/fsl: add MSI support for the Freescale hypervisor
  arch/powerpc/sysdev/fsl_rmu.c: introduce missing kfree
  powerpc/fsl: Add support for Integrated Flash Controller
  powerpc/fsl: update compatiable on fsl 16550 uart nodes
  powerpc/85xx: fix PCI and localbus properties in p1022ds.dts
  powerpc/85xx: re-enable ePAPR byte channel driver in corenet32_smp_defconfig
  powerpc/fsl: Update defconfigs to enable some standard FSL HW features
  powerpc: Add TBI PHY node to first MDIO bus
  sbc834x: put full compat string in board match check
  powerpc/fsl-pci: Allow 64-bit PCIe devices to DMA to any memory address
  powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit
  offb: Fix setting of the pseudo-palette for >8bpp
  offb: Add palette hack for qemu "standard vga" framebuffer
  offb: Fix bug in calculating requested vram size
  powerpc/boot: Change the WARN to INFO for boot wrapper overlap message
  powerpc/44x: Fix build error on currituck platform
  powerpc/boot: Change the load address for the wrapper to fit the kernel
  powerpc/44x: Enable CRASH_DUMP for 440x
  ...

Fix up a trivial conflict in arch/powerpc/include/asm/cputime.h due to
the additional sparse-checking code for cputime_t.
2012-01-06 17:58:22 -08:00
Greg Kroah-Hartman ff4b8a57f0 Merge branch 'driver-core-next' into Linux 3.2
This resolves the conflict in the arch/arm/mach-s3c64xx/s3c6400.c file,
and it fixes the build error in the arch/x86/kernel/microcode_core.c
file, that the merge did not catch.

The microcode_core.c patch was provided by Stephen Rothwell
<sfr@canb.auug.org.au> who was invaluable in the merge issues involved
with the large sysdev removal process in the driver-core tree.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2012-01-06 11:42:52 -08:00
Kay Sievers 8a25a2fd12 cpu: convert 'cpu' and 'machinecheck' sysdev_class to a regular subsystem
This moves the 'cpu sysdev_class' over to a regular 'cpu' subsystem
and converts the devices to regular devices. The sysdev drivers are
implemented as subsystem interfaces now.

After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.

Userspace relies on events and generic sysfs subsystem infrastructure
from sysdev devices, which are made available with this conversion.

Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: Len Brown <lenb@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-21 14:29:42 -08:00
Suzuki Poulose 368ff8f14d powerpc: Define virtual-physical translations for RELOCATABLE
We find the runtime address of _stext and relocate ourselves based
on the following calculation.

	virtual_base = ALIGN(KERNELBASE,KERNEL_TLB_PIN_SIZE) +
			MODULO(_stext.run,KERNEL_TLB_PIN_SIZE)

relocate() is called with the Effective Virtual Base Address (as
shown below)

            | Phys. Addr| Virt. Addr |
Page        |------------------------|
Boundary    |           |            |
            |           |            |
            |           |            |
Kernel Load |___________|_ __ _ _ _ _|<- Effective
Addr(_stext)|           |      ^     |Virt. Base Addr
            |           |      |     |
            |           |      |     |
            |           |reloc_offset|
            |           |      |     |
            |           |      |     |
            |           |______v_____|<-(KERNELBASE)%TLB_SIZE
            |           |            |
            |           |            |
            |           |            |
Page        |-----------|------------|
Boundary    |           |            |

On BookE, we need __va() & __pa() early in the boot process to access
the device tree.

Currently this has been defined as :

#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) -
						PHYSICAL_START + KERNELBASE)
where:
 PHYSICAL_START is kernstart_addr - a variable updated at runtime.
 KERNELBASE	is the compile time Virtual base address of kernel.

This won't work for us, as kernstart_addr is dynamic and will yield different
results for __va()/__pa() for same mapping.

e.g.,

Let the kernel be loaded at 64MB and KERNELBASE be 0xc0000000 (same as
PAGE_OFFSET).

In this case, we would be mapping 0 to 0xc0000000, and kernstart_addr = 64M

Now __va(1MB) = (0x100000) - (0x4000000) + 0xc0000000
		= 0xbc100000 , which is wrong.

it should be : 0xc0000000 + 0x100000 = 0xc0100000

On platforms which support AMP, like PPC_47x (based on 44x), the kernel
could be loaded at highmem. Hence we cannot always depend on the compile
time constants for mapping.

Here are the possible solutions:

1) Update kernstart_addr(PHSYICAL_START) to match the Physical address of
compile time KERNELBASE value, instead of the actual Physical_Address(_stext).

The disadvantage is that we may break other users of PHYSICAL_START. They
could be replaced with __pa(_stext).

2) Redefine __va() & __pa() with relocation offset

#ifdef	CONFIG_RELOCATABLE_PPC32
#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) - PHYSICAL_START + (KERNELBASE + RELOC_OFFSET)))
#define __pa(x) ((unsigned long)(x) + PHYSICAL_START - (KERNELBASE + RELOC_OFFSET))
#endif

where, RELOC_OFFSET could be

  a) A variable, say relocation_offset (like kernstart_addr), updated
     at boot time. This impacts performance, as we have to load an additional
     variable from memory.

		OR

  b) #define RELOC_OFFSET ((PHYSICAL_START & PPC_PIN_SIZE_OFFSET_MASK) - \
                      (KERNELBASE & PPC_PIN_SIZE_OFFSET_MASK))

   This introduces more calculations for doing the translation.

3) Redefine __va() & __pa() with a new variable

i.e,

#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) + VIRT_PHYS_OFFSET))

where VIRT_PHYS_OFFSET :

#ifdef CONFIG_RELOCATABLE_PPC32
#define VIRT_PHYS_OFFSET virt_phys_offset
#else
#define VIRT_PHYS_OFFSET (KERNELBASE - PHYSICAL_START)
#endif /* CONFIG_RELOCATABLE_PPC32 */

where virt_phy_offset is updated at runtime to :

	Effective KERNELBASE - kernstart_addr.

Taking our example, above:

virt_phys_offset = effective_kernelstart_vaddr - kernstart_addr
		 = 0xc0400000 - 0x400000
		 = 0xc0000000
	and

	__va(0x100000) = 0xc0000000 + 0x100000 = 0xc0100000
	 which is what we want.

I have implemented (3) in the following patch which has same cost of
operation as the existing one.

I have tested the patches on 440x platforms only. However this should
work fine for PPC_47x also, as we only depend on the runtime address
and the current TLB XLAT entry for the startup code, which is available
in r25. I don't have access to a 47x board yet. So, it would be great if
somebody could test this on 47x.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2011-12-20 10:21:34 -05:00
Suzuki Poulose 0f890c8d20 powerpc: Rename mapping based RELOCATABLE to DYNAMIC_MEMSTART for BookE
The current implementation of CONFIG_RELOCATABLE in BookE is based
on mapping the page aligned kernel load address to KERNELBASE. This
approach however is not enough for platforms, where the TLB page size
is large (e.g, 256M on 44x). So we are renaming the RELOCATABLE used
currently in BookE to DYNAMIC_MEMSTART to reflect the actual method.

The CONFIG_RELOCATABLE for PPC32(BookE) based on processing of the
dynamic relocations will be introduced in the later in the patch series.

This change would allow the use of the old method of RELOCATABLE for
platforms which can afford to enforce the page alignment (platforms with
smaller TLB size).

Changes since v3:

* Introduced a new config, NONSTATIC_KERNEL, to denote a kernel which is
  either a RELOCATABLE or DYNAMIC_MEMSTART(Suggested by: Josh Boyer)

Suggested-by: Scott Wood <scottwood@freescale.com>
Tested-by: Scott Wood <scottwood@freescale.com>

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Cc: Scott Wood <scottwood@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Josh Boyer <jwboyer@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linux ppc dev <linuxppc-dev@lists.ozlabs.org>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2011-12-20 10:20:19 -05:00
David Rientjes 2011b1d0d3 powerpc/mm: Fix section mismatch for read_n_cells
read_n_cells() cannot be marked as .devinit.text since it is referenced
from two functions that are not in that section: of_get_lmb_size() and
hot_add_drconf_scn_to_nid().

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-19 14:41:18 +11:00
David Rientjes 28e86bdbc9 powerpc/mm: Fix section mismatch for mark_reserved_regions_for_nid
mark_reserved_regions_for_nid() is only called from do_init_bootmem(),
which is in .init.text, so it must be in the same section to avoid a
section mismatch warning.

Reported-by: Subrata Modak <subrata@linux.vnet.ibm.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-19 14:41:16 +11:00
Benjamin Herrenschmidt 1e7342e778 Merge remote-tracking branch 'jwb/next' into next
Conflicts:
	arch/powerpc/platforms/40x/ppc40x_simple.c
2011-12-16 11:24:25 +11:00
Christoph Egger ca899859f1 powerpc/44x: Removing dead CONFIG_PPC47x
CONFIG_PPC47x doesn't exist in Kconfig and no 476 processor calls this
function ppc44x_pin_tlb() as it has it's own ppc47x_pin_tlb().

This code is probably an artifact of the original 476 code that
shouldn't have made it upstream.

Signed-off-by: Christoph Egger <siccegge@cs.fau.de>
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2011-12-09 07:48:56 -05:00
Tejun Heo 1d7cfe18ec powerpc: Use HAVE_MEMBLOCK_NODE_MAP
powerpc doesn't access early_node_map[] directly and enabling
HAVE_MEMBLOCK_NODE_MAP is trivial - replacing add_active_range() calls
with memblock_set_node() and selecting HAVE_MEMBLOCK_NODE_MAP is
enough.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
2011-12-08 10:22:08 -08:00
Tejun Heo 1aadc0560f memblock: s/memblock_analyze()/memblock_allow_resize()/ and update users
The only function of memblock_analyze() is now allowing resize of
memblock region arrays.  Rename it to memblock_allow_resize() and
update its users.

* The following users remain the same other than renaming.

  arm/mm/init.c::arm_memblock_init()
  microblaze/kernel/prom.c::early_init_devtree()
  powerpc/kernel/prom.c::early_init_devtree()
  openrisc/kernel/prom.c::early_init_devtree()
  sh/mm/init.c::paging_init()
  sparc/mm/init_64.c::paging_init()
  unicore32/mm/init.c::uc32_memblock_init()

* In the following users, analyze was used to update total size which
  is no longer necessary.

  powerpc/kernel/machine_kexec.c::reserve_crashkernel()
  powerpc/kernel/prom.c::early_init_devtree()
  powerpc/mm/init_32.c::MMU_init()
  powerpc/mm/tlb_nohash.c::__early_init_mmu()  
  powerpc/platforms/ps3/mm.c::ps3_mm_add_memory()
  powerpc/platforms/embedded6xx/wii.c::wii_memory_fixups()
  sh/kernel/machine_kexec.c::reserve_crashkernel()

* x86/kernel/e820.c::memblock_x86_fill() was directly setting
  memblock_can_resize before populating memblock and calling analyze
  afterwards.  Call memblock_allow_resize() before start populating.

memblock_can_resize is now static inside memblock.c.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: "H. Peter Anvin" <hpa@zytor.com>
2011-12-08 10:22:08 -08:00
Tejun Heo 6fbef13c4f powerpc: Cleanup memblock usage
* early_init_devtree(): Total memory size is aligned to PAGE_SIZE;
  however, alignment isn't enforced if memory_limit is explicitly
  specified.  Simplify the logic and always apply PAGE_SIZE alignment.

* MMU_init(): memblock regions is truncated by directly modifying
  memblock.memory.cnt.  This is incomplete (reserved array is not
  truncated) and unnecessarily low level hindering further memblock
  improvments.  Use memblock_enforce_memory_limit() instead.

* wii_memory_fixups(): Unnecessarily low level direct manipulation of
  memblock regions.  The same result can be achieved using properly
  abstracted operations.  Reimplement using memblock API.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
2011-12-08 10:22:07 -08:00
sukadev@linux.vnet.ibm.com 8a3e3d31d1 powerpc: Punch a hole in /dev/mem for librtas
With CONFIG_STRICT_DEVMEM=y, user space cannot read any part of /dev/mem.
Since this breaks librtas, punch a hole in /dev/mem to allow access to the
rmo_buffer that librtas needs.

Anton Blanchard reported the problem and helped with the fix.

A quick test for this patch:

       # cat /proc/rtas/rmo_buffer
       000000000f190000 10000

       # python -c "print 0x000000000f190000 / 0x10000"
       3865

       # dd if=/dev/mem of=/tmp/foo count=1 bs=64k skip=3865
       1+0 records in
       1+0 records out
       65536 bytes (66 kB) copied, 0.000205235 s, 319 MB/s

       # dd if=/dev/mem of=/tmp/foo
       dd: reading `/dev/mem': Operation not permitted
       0+0 records in
       0+0 records out
       0 bytes (0 B) copied, 0.00022519 s, 0.0 kB/s

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-08 14:22:52 +11:00
Becky Bruce d93e4d7d72 powerpc/book3e: Change hugetlb preload to take vma argument
This avoids an extra find_vma() and is less error-prone.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:24 +11:00
Becky Bruce a6146888be powerpc: Add gpages reservation code for 64-bit FSL BOOKE
For 64-bit FSL_BOOKE implementations, gigantic pages need to be
reserved at boot time by the memblock code based on the command line.
This adds the call that handles the reservation, and fixes some code
comments.

It also removes the previous pr_err when reserve_hugetlb_gpages
is called on a system without hugetlb enabled - the way the code is
structured, the call is unconditional and the resulting error message
spurious and confusing.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:23 +11:00
Becky Bruce d1b9b12811 powerpc: Add hugepage support to 64-bit tablewalk code for FSL_BOOK3E
Before hugetlb, at each level of the table, we test for
!0 to determine if we have a valid table entry.  With hugetlb, this
compare becomes:
        < 0 is a normal entry
        0 is an invalid entry
        > 0 is huge

This works because the hugepage code pulls the top bit off the entry
(which for non-huge entries always has the top bit set) as an
indicator that we have a hugepage.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:22 +11:00
Becky Bruce 27609a42ee powerpc: Whitespace/comment changes to tlb_low_64e.S
I happened to comment this code while I was digging through it;
we might as well commit that.  I also made some whitespace
changes - the existing code had a lot of unnecessary newlines
that I found annoying when I was working on my tiny laptop.

No functional changes.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:22 +11:00
Becky Bruce 881fde1db5 powerpc: hugetlb: modify include usage for FSL BookE code
The original 32-bit hugetlb implementation used PPC64 vs PPC32 to
determine which code path to take.  However, the final hugetlb
implementation for 64-bit FSL ended up shared with the FSL
32-bit code so the actual check needs to be FSL_BOOK3E vs
everything else.  This patch changes the include protections to
reflect this.

There are also a couple of related comment fixes.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:22 +11:00
Becky Bruce a1cd541988 powerpc: Update hugetlb huge_pte_alloc and tablewalk code for FSL BOOKE
This updates the hugetlb page table code to handle 64-bit FSL_BOOKE.
The previous 32-bit work counted on the inner levels of the page table
collapsing.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:22 +11:00
Becky Bruce 8c1674de2b powerpc: Fix booke hugetlb preload code for PPC_MM_SLICES and 64-bit
This patch does 2 things: It corrects the code that determines the
size to write into MAS1 for the PPC_MM_SLICES case (this originally
came from David Gibson and I had incorrectly altered it), and it
changes the methodolody used to calculate the size for !PPC_MM_SLICES
to work for 64-bit as well as 32-bit.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:21 +11:00
Becky Bruce 7651295944 powerpc: Only define HAVE_ARCH_HUGETLB_UNMAPPED_AREA if PPC_MM_SLICES
If we don't have slices, we should be able to use the generic
hugetlb_get_unmapped_area() code

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-12-07 16:26:21 +11:00
Justin P. Mattock 42b2aa86c6 treewide: Fix typos in various parts of the kernel, and fix some comments.
The below patch fixes some typos in various parts of the kernel, as well as fixes some comments.
Please let me know if I missed anything, and I will try to get it changed and resent.

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-12-02 14:57:31 +01:00
Tejun Heo d4bbf7e775 Merge branch 'master' into x86/memblock
Conflicts & resolutions:

* arch/x86/xen/setup.c

	dc91c728fd "xen: allow extra memory to be in multiple regions"
	24aa07882b "memblock, x86: Replace memblock_x86_reserve/free..."

	conflicted on xen_add_extra_mem() updates.  The resolution is
	trivial as the latter just want to replace
	memblock_x86_reserve_range() with memblock_reserve().

* drivers/pci/intel-iommu.c

	166e9278a3 "x86/ia64: intel-iommu: move to drivers/iommu/"
	5dfe8660a3 "bootmem: Replace work_with_active_regions() with..."

	conflicted as the former moved the file under drivers/iommu/.
	Resolved by applying the chnages from the latter on the moved
	file.

* mm/Kconfig

	6661672053 "memblock: add NO_BOOTMEM config symbol"
	c378ddd53f "memblock, x86: Make ARCH_DISCARD_MEMBLOCK a config option"

	conflicted trivially.  Both added config options.  Just
	letting both add their own options resolves the conflict.

* mm/memblock.c

	d1f0ece6cd "mm/memblock.c: small function definition fixes"
	ed7b56a799 "memblock: Remove memblock_memory_can_coalesce()"

	confliected.  The former updates function removed by the
	latter.  Resolution is trivial.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-11-28 09:46:22 -08:00
Dan McGee fa8cbaaf5a powerpc+sparc64/mm: Remove hack in mmap randomize layout
Since commit 8a0a9bd4db, this comment in mmap_rnd() does not
hold true as the value returned by get_random_int() will in fact be

different every single call. Remove the comment and simplify the code
back to its original desired form.

This reverts commit a5adc91a4b which is no longer necessary and
also fixes the sparc code that copied this same adjustment.

Signed-off-by: Dan McGee <dpmcgee@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-28 11:42:09 +11:00
sukadev@linux.vnet.ibm.com 1d54cf2b97 powerpc: Implement CONFIG_STRICT_DEVMEM
As described in the help text in the patch, this token restricts general
access to /dev/mem as a way of increasing the security. Specifically, access
to exclusive IOMEM and kernel RAM is denied unless CONFIG_STRICT_DEVMEM is
set to 'n'.

Implement the 'devmem_is_allowed()' interface for Powerpc. It will be
called from range_is_allowed() when userpsace attempts to access /dev/mem.

This patch is based on an earlier patch from Steve Best and with input from
Paul Mackerras and Scott Wood.

[BenH] Fixed a typo or two and removed the generic change which should
       be submitted as a separate patch

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-28 11:42:08 +11:00
Jimi Xenidis c3dcf53a3f powerpc/icswx: Simple ACOP fault handler
This patch adds a fault handler that responds to illegal Coprocessor
types.  Currently all CTs are treated and illegal.  There are two ways
to report the fault back to the application.  If the application used
the record form ("icswx.") then the architected "reject" is emulated.
If the application did not used the record form ("icswx") then it is
selectable by config whether the failure is silent (as architected) or
a SIGILL is generated.

In all cases pr_warn() is used to log the bad CT.

Signed-off-by: Jimi Xenidis <jimix@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-25 14:11:28 +11:00
Jimi Xenidis 9d67028090 powerpc: Split ICSWX ACOP and PID processing
Some processors, like embedded, that already have a PID register that
is managed by the system.  This patch separates the ACOP and PID
processing into separate files so that the ACOP code can be shared.

Signed-off-by: Jimi Xenidis <jimix@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-25 14:11:27 +11:00
Kumar Gala 13020be8be powerpc: Fix compiliation with hugetlbfs enabled
arch/powerpc/mm/hugetlbpage.c: In function 'reserve_hugetlb_gpages':
arch/powerpc/mm/hugetlbpage.c:312:2: error: implicit declaration of function 'parse_args'

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-25 10:05:59 +11:00
Dipankar Sarma 1c8ee73395 powerpc/numa: NUMA topology support for PowerNV
This patch adds support for numa topology on powernv platforms running
OPAL formware. It checks for the type of platform at run time and
sets the affinity form correctly so that NUMA topology can be discovered
correctly.

Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-08 14:51:46 +11:00
Anton Blanchard c40dd2f766 powerpc: Add System RAM to /proc/iomem
We've resisted adding System RAM to /proc/iomem because it is
the wrong place for it. Unfortunately we continue to find tools
that rely on this behaviour so give up and add it in.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-11-08 14:51:46 +11:00
Linus Torvalds 32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Linus Torvalds 1197ab2942 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (106 commits)
  powerpc/p3060qds: Add support for P3060QDS board
  powerpc/83xx: Add shutdown request support to MCU handling on MPC8349 MITX
  powerpc/85xx: Make kexec to interate over online cpus
  powerpc/fsl_booke: Fix comment in head_fsl_booke.S
  powerpc/85xx: issue 15 EOI after core reset for FSL CoreNet devices
  powerpc/8xxx: Fix interrupt handling in MPC8xxx GPIO driver
  powerpc/85xx: Add 'fsl,pq3-gpio' compatiable for GPIO driver
  powerpc/86xx: Correct Gianfar support for GE boards
  powerpc/cpm: Clear muram before it is in use.
  drivers/virt: add ioctl for 32-bit compat on 64-bit to fsl-hv-manager
  powerpc/fsl_msi: add support for "msi-address-64" property
  powerpc/85xx: Setup secondary cores PIR with hard SMP id
  powerpc/fsl-booke: Fix settlbcam for 64-bit
  powerpc/85xx: Adding DCSR node to dtsi device trees
  powerpc/85xx: clean up FPGA device tree nodes for Freecsale QorIQ boards
  powerpc/85xx: fix PHYS_64BIT selection for P1022DS
  powerpc/fsl-booke: Fix setup_initial_memory_limit to not blindly map
  powerpc: respect mem= setting for early memory limit setup
  powerpc: Update corenet64_smp_defconfig
  powerpc: Update mpc85xx/corenet 32-bit defconfigs
  ...

Fix up trivial conflicts in:
 - arch/powerpc/configs/40x/hcu4_defconfig
	removed stale file, edited elsewhere
 - arch/powerpc/include/asm/udbg.h, arch/powerpc/kernel/udbg.c:
	added opal and gelic drivers vs added ePAPR driver
 - drivers/tty/serial/8250.c
	moved UPIO_TSI to powerpc vs removed UPIO_DWAPB support
2011-11-06 17:12:03 -08:00
Andrea Arcangeli b35a35b556 thp: share get_huge_page_tail()
This avoids duplicating the function in every arch gup_fast.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:58 -07:00
Andrea Arcangeli cf592bf768 powerpc: gup_huge_pmd() return 0 if pte changes
powerpc didn't return 0 in that case, if it's rolling back the *nr pointer
it should also return zero to avoid adding pages to the array at the wrong
offset.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:57 -07:00
Andrea Arcangeli 3526741f09 powerpc: gup_hugepte() support THP based tail recounting
Up to this point the code assumed old refcounting for hugepages (pre-thp).
This updates the code directly to the thp mapcount tail page refcounting.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:57 -07:00
Andrea Arcangeli 8596468487 powerpc: gup_hugepte() avoid freeing the head page too many times
We only taken "refs" pins on the head page not "*nr" pins.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:57 -07:00
Andrea Arcangeli 405e44f2e3 powerpc: get_hugepte() don't put_page() the wrong page
"page" may have changed to point to the next hugepage after the loop
completed, The references have been taken on the head page, so the
put_page must happen there too.

This is a longstanding issue pre-thp inclusion.

It's totally unclear how these page_cache_add_speculative and
pte_val(pte) != pte_val(*ptep) checks are necessary across all the
powerpc gup_fast code, when x86 doesn't need any of that: there's no way
the page can be freed with irq disabled so we're guaranteed the
atomic_inc will happen on a page with page_count > 0 (so not needing the
speculative check).

The pte check is also meaningless on x86: no need to rollback on x86 if
the pte changed, because the pte can still change a CPU tick after the
check succeeded and it won't be rolled back in that case.  The important
thing is we got a reference on a valid page that was mapped there a CPU
tick ago.  So not knowing the soft tlb refill code of ppc64 in great
detail I'm not removing the "speculative" page_count increase and the
pte checks across all the code, but unless there's a strong reason for
it they should be later cleaned up too.

If a pte can change from huge to non-huge (like it could happen with
THP) passing a pte_t *ptep to gup_hugepte() would also require to repeat
the is_hugepd in gup_hugepte(), but that shouldn't happen with hugetlbfs
only so I'm not altering that.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:57 -07:00
Andrea Arcangeli 2839bdc1bf powerpc: remove superfluous PageTail checks on the pte gup_fast
This part of gup_fast doesn't seem capable of handling hugetlbfs ptes,
those should be handled by gup_hugepd only, so these checks are
superfluous.

Plus if this wasn't a noop, it would have oopsed because, the insistence
of using the speculative refcounting would trigger a VM_BUG_ON if a tail
page was encountered in the page_cache_get_speculative().

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:57 -07:00
Andrea Arcangeli 70b50f94f1 mm: thp: tail page refcounting fix
Michel while working on the working set estimation code, noticed that
calling get_page_unless_zero() on a random pfn_to_page(random_pfn)
wasn't safe, if the pfn ended up being a tail page of a transparent
hugepage under splitting by __split_huge_page_refcount().

He then found the problem could also theoretically materialize with
page_cache_get_speculative() during the speculative radix tree lookups
that uses get_page_unless_zero() in SMP if the radix tree page is freed
and reallocated and get_user_pages is called on it before
page_cache_get_speculative has a chance to call get_page_unless_zero().

So the best way to fix the problem is to keep page_tail->_count zero at
all times.  This will guarantee that get_page_unless_zero() can never
succeed on any tail page.  page_tail->_mapcount is guaranteed zero and
is unused for all tail pages of a compound page, so we can simply
account the tail page references there and transfer them to
tail_page->_count in __split_huge_page_refcount() (in addition to the
head_page->_mapcount).

While debugging this s/_count/_mapcount/ change I also noticed get_page is
called by direct-io.c on pages returned by get_user_pages.  That wasn't
entirely safe because the two atomic_inc in get_page weren't atomic.  As
opposed to other get_user_page users like secondary-MMU page fault to
establish the shadow pagetables would never call any superflous get_page
after get_user_page returns.  It's safer to make get_page universally safe
for tail pages and to use get_page_foll() within follow_page (inside
get_user_pages()).  get_page_foll() is safe to do the refcounting for tail
pages without taking any locks because it is run within PT lock protected
critical sections (PT lock for pte and page_table_lock for
pmd_trans_huge).

The standard get_page() as invoked by direct-io instead will now take
the compound_lock but still only for tail pages.  The direct-io paths
are usually I/O bound and the compound_lock is per THP so very
finegrined, so there's no risk of scalability issues with it.  A simple
direct-io benchmarks with all lockdep prove locking and spinlock
debugging infrastructure enabled shows identical performance and no
overhead.  So it's worth it.  Ideally direct-io should stop calling
get_page() on pages returned by get_user_pages().  The spinlock in
get_page() is already optimized away for no-THP builds but doing
get_page() on tail pages returned by GUP is generally a rare operation
and usually only run in I/O paths.

This new refcounting on page_tail->_mapcount in addition to avoiding new
RCU critical sections will also allow the working set estimation code to
work without any further complexity associated to the tail page
refcounting with THP.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-02 16:06:57 -07:00
Paul Gortmaker 4b16f8e2d6 powerpc: various straight conversions from module.h --> export.h
All these files were including module.h just for the basic
EXPORT_SYMBOL infrastructure.  We can shift them off to the
export.h header which is a way smaller footprint and thus
realize some compile time gains.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:44 -04:00
Paul Gortmaker 9308794884 powerpc: include export.h for files using EXPORT_SYMBOL/THIS_MODULE
Fix failures in powerpc associated with the previously allowed
implicit module.h presence that now lead to things like this:

arch/powerpc/mm/mmu_context_hash32.c:76:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/powerpc/mm/tlb_hash32.c:48:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
arch/powerpc/kernel/pci_32.c:51:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/powerpc/kernel/iomap.c:36:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
arch/powerpc/platforms/44x/canyonlands.c:126:1: error: type defaults to 'int' in declaration of 'EXPORT_SYMBOL'
arch/powerpc/kvm/44x.c:168:59: error: 'THIS_MODULE' undeclared (first use in this function)

[with several contibutions from Stephen Rothwell <sfr@canb.auug.org.au>]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:30:38 -04:00