Commit Graph

1667 Commits

Author SHA1 Message Date
Victor Kamensky 1e3479225a ARM: 8275/1: mm: fix PMD_SECT_RDONLY undeclared compile error
In v3.19-rc3 tree when CONFIG_ARM_LPAE and CONFIG_DEBUG_RODATA are enabled
image failed to compile with the following error:

arch/arm/mm/init.c:661:14: error: ‘PMD_SECT_RDONLY’ undeclared here (not in a function)

It seems that '80d6b0c ARM: mm: allow text and rodata sections to be read-only'
and 'ded9477 ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE'
commits crossed. 80d6b0c uses PMD_SECT_RDONLY macro but ded9477 renames it
and uses software bits L_PMD_SECT_RDONLY instead.

Fix is to use L_PMD_SECT_RDONLY instead PMD_SECT_RDONLY as ded9477 does in
another places.

Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-01-09 20:44:12 +00:00
Grygorii Strashko ac08468867 ARM: 8253/1: mm: use phys_addr_t type in map_lowmem() for kernel mem region
Now local variables kernel_x_start and kernel_x_end defined using
'unsigned long' type which is wrong because they represent physical
memory range and will be calculated wrongly if LPAE is enabled.
As result, all following code in map_lowmem() will not work correctly.

For example, Keystone 2 boot is broken because
 kernel_x_start == 0x0000 0000
 kernel_x_end   == 0x0080 0000

instead of
 kernel_x_start == 0x0000 0008 0000 0000
 kernel_x_end   == 0x0000 0008 0080 0000
and as result whole low memory will be mapped with MT_MEMORY_RW
permissions by code (start > kernel_x_end):
		} else if (start >= kernel_x_end) {
			map.pfn = __phys_to_pfn(start);
			map.virtual = __phys_to_virt(start);
			map.length = end - start;
			map.type = MT_MEMORY_RW;

			create_mapping(&map);
		}

Hence, fix it by using phys_addr_t type for variables kernel_x_start
and kernel_x_end.

Tested-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-01-07 20:33:34 +00:00
Mark Rutland cca547e9aa ARM: 8249/1: mm: dump: don't skip regions
Currently the arm page table dumping code starts dumping page tables
from USER_PGTABLES_CEILING. This is unnecessary for skipping any entries
related to userspace as the swapper_pg_dir does not contain such
entries, and results in a couple of unfortuante side effects.

Firstly, any kernel mappings which might exist below
USER_PGTABLES_CEILING will not be accounted in the dump output. This
masks any entries erroneously created below this address.

Secondly, if the final page table entry walked is part of a valid
mapping the page table dumping code will not log the region this entry
is part of, as the final note_page call in walk_pgd will trigger an
early return when 0 < USER_PGTABLES_CEILING. Luckily this isn't seen on
contemporary systems as they typically don't have enough RAM to extend
the linear mapping right to the end of the address space.

Due to the way addr is constructed in the walk_* functions, it can never
be less than USER_PGTABLES_CEILING when walking the page tables, so it
is not necessary to avoid dereferencing invalid table addresses. The
existing checks for st->current_prot and st->marker[1].start_address are
sufficient to ensure we will not print and/or dereference garbage when
trying to log information.

This patch removes both problematic uses of USER_PGTABLES_CEILING from
the arm page table dumping code, preventing both of these issues. We
will now report any low mappings, and the final note_page call will not
return early, ensuring all regions are logged.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2015-01-07 20:33:33 +00:00
Linus Torvalds 6f51ee709e Merge tag 'iommu-config-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC/iommu configuration update from Arnd Bergmann:
 "The iomm-config branch contains work from Will Deacon, quoting his
  description:

    This series adds automatic IOMMU and DMA-mapping configuration for
    OF-based DMA masters described using the generic IOMMU devicetree
    bindings. Although there is plenty of future work around splitting up
    iommu_ops, adding default IOMMU domains and sorting out automatic IOMMU
    group creation for the platform_bus, this is already useful enough for
    people to port over their IOMMU drivers and start using the new probing
    infrastructure (indeed, Marek has patches queued for the Exynos IOMMU).

  The branch touches core ARM and IOMMU driver files, and the respective
  maintainers (Russell King and Joerg Roedel) agreed to have the
  contents merged through the arm-soc tree.

  The final version was ready just before the merge window, so we ended
  up delaying it a bit longer than the rest, but we don't expect to see
  regressions because this is just additional infrastructure that will
  get used in drivers starting in 3.20 but is unused so far"

* tag 'iommu-config-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  iommu: store DT-probed IOMMU data privately
  arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops
  arm: call iommu_init before of_platform_populate
  dma-mapping: detect and configure IOMMU in of_dma_configure
  iommu: fix initialization without 'add_device' callback
  iommu: provide helper function to configure an IOMMU for an of master
  iommu: add new iommu_ops callback for adding an OF device
  dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops
  iommu: provide early initialisation hook for IOMMU drivers
2014-12-16 14:53:01 -08:00
Linus Torvalds 26ceb127f7 Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
 "The major updates included in this update are:

   - Clang compatible stack pointer accesses by Behan Webster.
   - SA11x0 updates from Dmitry Eremin-Solenikov.
   - kgdb handling of breakpoints with read-only text/modules
   - Support for Privileged-no-execute feature on ARMv7 to prevent
     userspace code execution by the kernel.
   - AMBA primecell bus handling of irq-safe runtime PM
   - Unwinding support for memset/memzero/memmove/memcpy functions
   - VFP fixes for Krait CPUs and improvements in detecting the VFP
     architecture
   - A number of code cleanups (using pr_*, removing or reducing the
     severity of a couple of kernel messages, splitting ftrace asm code
     out to a separate file, etc.)
   - Add machine name to stack dump output"

* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (62 commits)
  ARM: 8247/2: pcmcia: sa1100: make use of device clock
  ARM: 8246/2: pcmcia: sa1111: provide device clock
  ARM: 8245/1: pcmcia: soc-common: enable/disable socket clocks
  ARM: 8244/1: fbdev: sa1100fb: make use of device clock
  ARM: 8243/1: sa1100: add a clock alias for sa1111 pcmcia device
  ARM: 8242/1: sa1100: add cpu clock
  ARM: 8221/1: PJ4: allow building in Thumb-2 mode
  ARM: 8234/1: sa1100: reorder IRQ handling code
  ARM: 8233/1: sa1100: switch to hwirq usage
  ARM: 8232/1: sa1100: merge GPIO multiplexer IRQ to "normal" irq domain
  ARM: 8231/1: sa1100: introduce irqdomains support
  ARM: 8230/1: sa1100: shift IRQs by one
  ARM: 8229/1: sa1100: replace irq numbers with names in irq driver
  ARM: 8228/1: sa1100: drop entry-macro.S
  ARM: 8227/1: sa1100: switch to MULTI_IRQ_HANDLER
  ARM: 8241/1: Update processor_modes for hyp and monitor mode
  ARM: 8240/1: MCPM: document mcpm_sync_init()
  ARM: 8239/1: Introduce {set,clear}_pte_bit
  ARM: 8238/1: mm: Refine set_memory_* functions
  ARM: 8237/1: fix flush_pfn_alias
  ...
2014-12-12 15:26:48 -08:00
Linus Torvalds 6cd94d5e57 Merge tag 'soc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC platform changes from Arnd Bergmann:
 "New and updated SoC support, notable changes include:

   - bcm:
        brcmstb SMP support
        initial iproc/cygnus support
   - exynos:
        Exynos4415 SoC support
        PMU and suspend support for Exynos5420
        PMU support for Exynos3250
        pm related maintenance
   - imx:
        new LS1021A SoC support
        vybrid 610 global timer support
   - integrator:
        convert to using multiplatform configuration
   - mediatek:
        earlyprintk support for mt8127/mt8135
   - meson:
        meson8 soc and l2 cache controller support
   - mvebu:
        Armada 38x CPU hotplug support
        drop support for prerelease Armada 375 Z1 stepping
        extended suspend support, now works on Armada 370/XP
   - omap:
        hwmod related maintenance
        prcm cleanup
   - pxa:
        initial pxa27x DT handling
   - rockchip:
        SMP support for rk3288
        add cpu frequency scaling support
   - shmobile:
        r8a7740 power domain support
        various small restart, timer, pci apmu changes
   - sunxi:
        Allwinner A80 (sun9i) earlyprintk support
   - ux500:
        power domain support

  Overall, a significant chunk of changes, coming mostly from the usual
  suspects: omap, shmobile, samsung and mvebu, all of which already
  contain a lot of platform specific code in arch/arm"

* tag 'soc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (187 commits)
  ARM: mvebu: use the cpufreq-dt platform_data for independent clocks
  soc: integrator: Add terminating entry for integrator_cm_match
  ARM: mvebu: add SDRAM controller description for Armada XP
  ARM: mvebu: adjust mbus controller description on Armada 370/XP
  ARM: mvebu: add suspend/resume DT information for Armada XP GP
  ARM: mvebu: synchronize secondary CPU clocks on resume
  ARM: mvebu: make sure MMU is disabled in armada_370_xp_cpu_resume
  ARM: mvebu: Armada XP GP specific suspend/resume code
  ARM: mvebu: reserve the first 10 KB of each memory bank for suspend/resume
  ARM: mvebu: implement suspend/resume support for Armada XP
  clk: mvebu: add suspend/resume for gatable clocks
  bus: mvebu-mbus: provide a mechanism to save SDRAM window configuration
  bus: mvebu-mbus: suspend/resume support
  clocksource: time-armada-370-xp: add suspend/resume support
  irqchip: armada-370-xp: Add suspend/resume support
  ARM: add lolevel debug support for asm9260
  ARM: add mach-asm9260
  ARM: EXYNOS: use u8 for val[] in struct exynos_pmu_conf
  power: reset: imx-snvs-poweroff: add power off driver for i.mx6
  ARM: imx: temporarily remove CONFIG_SOC_FSL from LS1021A
  ...
2014-12-09 14:38:28 -08:00
Russell King e9f2d6d660 Merge branch 'devel-stable' into for-next 2014-12-05 16:30:54 +00:00
Russell King fbe4dd088f Merge branches 'fixes', 'misc', 'pm' and 'sa1100' into for-next 2014-12-05 16:30:47 +00:00
Jungseung Lee 4e802cfd74 ARM: 8238/1: mm: Refine set_memory_* functions
set_memory_* functions have same implementation
except memory attribute.

This patch makes to use common function for these, and pull out
the functions into arch/arm/mm/pageattr.c like arm64 did.
It will reduce code size and enhance the readability.

Signed-off-by: Jungseung Lee <js07.lee@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-12-03 16:00:05 +00:00
Jungseung Lee 12e669b487 ARM: 8237/1: fix flush_pfn_alias
L1_CACHE_BYTES could be larger than real L1 cache line size.
In that case, flush_pfn_alias() would omit to flush last bytes
as much as L1_CACHE_BYTES - real cache line size.

So fix end address to "to + PAGE_SIZE - 1". The bottom bits of the address
is LINELEN. that is ignored by mcrr.

Signed-off-by: Jungseung Lee <js07.lee@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-12-03 16:00:04 +00:00
Jungseung Lee 802318743a ARM: 8236/1: mm: fix discard_old_kernel_data
L1_CACHE_BYTES could be larger value than real L1 cache line size.
In that case, discard_old_kernel_data() would omit to invalidate
last bytes as much as L1_CACHE_BYTES - real cache line size.

So fix end address to "to + PAGE_SIZE -1". The bottom bits
of the address is LINELEN. that is ignored by mcrr.

Signed-off-by: Jungseung Lee <js07.lee@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-12-03 16:00:04 +00:00
Jungseung Lee 1d4d37159d ARM: 8235/1: Support for the PXN CPU feature on ARMv7
Modern ARMv7-A/R cores optionally implement below new
hardware feature:

- PXN:
Privileged execute-never(PXN) is a security feature. PXN bit
determines whether the processor can execute software from
the region. This is effective solution against ret2usr attack.
On an implementation that does not include the LPAE, PXN is
optionally supported.

This patch set PXN bit on user page table for preventing
user code execution with privilege mode.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jungseung Lee <js07.lee@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-12-03 15:57:45 +00:00
Will Deacon 4bb25789ed arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops
This patch plumbs the existing ARM IOMMU DMA infrastructure (which isn't
actually called outside of a few drivers) into arch_setup_dma_ops, so
that we can use IOMMUs for DMA transfers in a more generic fashion.

Since this significantly complicates the arch_setup_dma_ops function,
it is moved out of line into dma-mapping.c. If CONFIG_ARM_DMA_USE_IOMMU
is not set, the iommu parameter is ignored and the normal ops are used
instead.

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2014-12-01 16:51:35 +00:00
Linus Torvalds e818d5ed2a Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
 "Another round of relatively small ARM fixes.

  Thomas spotted that the strex backoff delay bit was a disable bit, so
  it needed to be clear for this to work.  Vladimir spotted that using a
  restart block for the cache flush operation would return -EINTR, which
  userspace was not expecting.  Dmitry spotted that the auxiliary
  control register accesses for Xscale were not correct"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8226/1: cacheflush: get rid of restarting block
  ARM: 8222/1: mvebu: enable strex backoff delay
  ARM: 8216/1: xscale: correct auxiliary register in suspend/resume
2014-11-28 13:32:47 -08:00
Thomas Petazzoni 995ab5189d ARM: 8222/1: mvebu: enable strex backoff delay
Under extremely rare conditions, in an MPCore node consisting of at
least 3 CPUs, two CPUs trying to perform a STREX to data on the same
shared cache line can enter a livelock situation.

This patch enables the HW mechanism that overcomes the bug. This fixes
the incorrect setup of the STREX backoff delay bit due to a wrong
description in the specification.

Note that enabling the STREX backoff delay mechanism is done by
leaving the bit *cleared*, while the bit was currently being set by
the proc-v7.S code.

[Thomas: adapt to latest mainline, slightly reword the commit log, add
stable markers.]

Fixes: de4901933f ("arm: mm: Add support for PJ4B cpu and init routines")

Cc: <stable@vger.kernel.org> # v3.8+
Signed-off-by: Nadav Haklai <nadavh@marvell.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-27 15:55:04 +00:00
Dmitry Eremin-Solenikov ef59a20ba3 ARM: 8216/1: xscale: correct auxiliary register in suspend/resume
According to the manuals I have, XScale auxiliary register should be
reached with opc_2 = 1 instead of crn = 1. cpu_xscale_proc_init
correctly uses c1, c0, 1 arguments, but cpu_xscale_do_suspend and
cpu_xscale_do_resume use c1, c1, 0. Correct suspend/resume functions to
also use c1, c0, 1.

The issue was primarily noticed thanks to qemu reporing "unsupported
instruction" on the pxa suspend path. Confirmed in PXA210/250 and PXA255
XScale Core manuals and in PXA270 and PXA320 Developers Guides.

Harware tested by me on tosa (pxa255). Robert confirmed on pxa270 board.

Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-21 15:25:17 +00:00
Russell King 4ed89f2228 ARM: convert printk(KERN_* to pr_*
Convert many (but not all) printk(KERN_* to pr_* to simplify the code.
We take the opportunity to join some printk lines together so we don't
split the message across several lines, and we also add a few levels
to some messages which were previously missing them.

Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-21 15:24:50 +00:00
Will Deacon a391263cd8 ARM: 8203/1: mm: try to re-use old ASID assignments following a rollover
Rather than unconditionally allocating a fresh ASID to an mm from an
older generation, attempt to re-use the old assignment where possible.

This can bring performance benefits on systems where the ASID is used to
tag things other than the TLB (e.g. branch prediction resources).

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-21 15:24:46 +00:00
Stephen Boyd 6f0f2a9f0f ARM: 8196/1: vfp: Workaround bad MVFR1 register on some Kraits
Certain versions of the Krait processor don't report that they
support the fused multiply accumulate instruction via the MVFR1
register despite the fact that they actually do. Unfortunately we
use this register to identify support for VFPv4. Override the
hwcap on all Krait processors to indicate support for VFPv4 to
workaround this.

Tested-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-21 15:24:41 +00:00
Linus Torvalds 5f01feb8b9 Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
 "Two fixes this time, one to ensure that the kuser helper option
  depends on MMU as they aren't available for noMMU targets (and if the
  option is selected, we end up oopsing.)

  The second fix plugs a corner case with the decompressor, ensuring
  that the instruction stream can see the relocated code in every case
  on ARMv7 CPUs"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8198/1: make kuser helpers depend on MMU
  ARM: 8191/1: decompressor: ensure I-side picks up relocated code
2014-11-15 15:45:07 -08:00
Nathan Lynch 08b964ff3c ARM: 8198/1: make kuser helpers depend on MMU
The kuser helpers page is not set up on non-MMU systems, so it does
not make sense to allow CONFIG_KUSER_HELPERS to be enabled when
CONFIG_MMU=n.  Allowing it to be set on !MMU results in an oops in
set_tls (used in execve and the arm_syscall trap handler):

Unhandled exception: IPSR = 00000005 LR = fffffff1
CPU: 0 PID: 1 Comm: swapper Not tainted 3.18.0-rc1-00041-ga30465a #216
task: 8b838000 ti: 8b82a000 task.ti: 8b82a000
PC is at flush_thread+0x32/0x40
LR is at flush_thread+0x21/0x40
pc : [<8f00157a>]    lr : [<8f001569>]    psr: 4100000b
sp : 8b82be20  ip : 00000000  fp : 8b83c000
r10: 00000001  r9 : 88018c84  r8 : 8bb85000
r7 : 8b838000  r6 : 00000000  r5 : 8bb77400  r4 : 8b82a000
r3 : ffff0ff0  r2 : 8b82a000  r1 : 00000000  r0 : 88020354
xPSR: 4100000b
CPU: 0 PID: 1 Comm: swapper Not tainted 3.18.0-rc1-00041-ga30465a #216
[<8f002bc1>] (unwind_backtrace) from [<8f002033>] (show_stack+0xb/0xc)
[<8f002033>] (show_stack) from [<8f00265b>] (__invalid_entry+0x4b/0x4c)

As best I can tell this issue existed for the set_tls ARM syscall
before commit fbfb872f5f "ARM: 8148/1: flush TLS and thumbee
register state during exec" consolidated the TLS manipulation code
into the set_tls helper function, but now that we're using it to flush
register state during execve, !MMU users encounter the oops at the
first exec.

Prevent CONFIG_MMU=n configurations from enabling
CONFIG_KUSER_HELPERS.

Fixes: fbfb872f5f (ARM: 8148/1: flush TLS and thumbee register state during exec)

Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Reported-by: Stefan Agner <stefan@agner.ch>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-13 23:45:21 +00:00
Linus Walleij dc680b989d ARM: fix multiplatform allmodcompile
Commit 68f3b875f7
"ARM: integrator: make the Integrator multiplatform"
broke allmodconfig like this:

>> arch/arm/include/asm/cmpxchg.h:114:2: error: #error
"SMP is not supported on this platform"
(etc)

This is due to the fact that as we turned on multiplatform
for the Integrator, this enabled a lot of non-applicable
CPU's to be selected for its multiplatform images, due to
a lot of "depends on ARCH_INTEGRATOR" restrictions in
arch/arm/mm/Kconfig for the different ARM CPU types.

Fix this by restricting the CPU selections to respective
multiplatform config, which now becomes a subset of the
possible Integrator configurations, or alternatively the
non-multiplatform config plus ARCH_INTEGRATOR, i.e.:

if (!ARCH_MULTIPLATFORM || ARCH_MULTI_Vx) &&
   (ARCH_INTEGRATOR || ARCH_FOO ...)

Since the Integrator has been converted to multiplatform,
this will often take the short form:

if (ARCH_MULTI_Vx && ARCH_INTEGRATOR)

If no other non-multiplatform platforms are elegible.

Reported-by: Build bot for Mark Brown <broonie@kernel.org>
Reported-by: Kbuild test robot <fengguang.wu@intel.com>
Suggested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2014-11-11 20:14:07 +01:00
Russell King 06e944b8e5 Merge tag 'ronx-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into devel-stable
generic fixmaps
ARM support for CONFIG_DEBUG_RODATA
2014-11-03 10:12:13 +00:00
Linus Torvalds 3c43de0ffd Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King:
 - add the new bpf syscall to ARM.
 - drop a redundant return statement in __iommu_alloc_remap()
 - fix a performance issue noticed by Thomas Petazzoni with
   kmap_atomic().
 - fix an issue with the L2 cache OF parsing code which caused it to
   incorrectly print warnings on each boot, and make the warning text
   more consistent with the rest of the code

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8180/1: mm: implement no-highmem fast path in kmap_atomic_pfn()
  ARM: 8183/1: l2c: Improve l2c310_of_parse() error message
  ARM: 8181/1: Drop extra return statement
  ARM: 8182/1: l2c: Make l2x0_cache_size_of_parse() return 'int'
  ARM: enable bpf syscall
2014-11-02 12:56:20 -08:00
Thomas Petazzoni 9ff0bb5ba6 ARM: 8180/1: mm: implement no-highmem fast path in kmap_atomic_pfn()
Since CONFIG_HIGHMEM got enabled on ARMv5 Kirkwood, we have noticed a
very significant drop in networking performance. The test were
conducted on an OpenBlocks A7 board. Without this patch, the outgoing
performance measured with iperf are:

 - highmem OFF, TSO OFF   544 Mbit/s
 - highmem OFF, TSO ON	  942 Mbit/s
 - highmem ON,  TSO OFF   306 Mbit/s
 - highmem ON,  TSO ON    246 Mbit/s

On this Kirkwood platform, the L2 cache is a Feroceon cache, and with
this cache, all the range operations have to be done on virtual
addresses and not physical addresses. Therefore, whenever
CONFIG_HIGHMEM is enabled, the cache maintenance operations call
kmap_atomic_pfn() and kunmap_atomic().

However, kmap_atomic_pfn() does not implement the same fast path for
non-highmem pages as the one implemented in kmap_atomic(), and this is
one of the reason for the performance drop. While this patch does not
fully restore the performances, it clearly improves them a lot:

      	      	        without patch  with patch

 - highmem ON, TSO OFF   306 Mbit/s     387 Mbit/s
 - highmem ON, TSO ON    246 Mbit/s     434 Mbit/s

We're still far from the !CONFIG_HIGHMEM performances, but it does
improve a bit the situation.

Thanks a lot to Ezequiel Garcia and Gregory Clement for all the
testing work around this topic.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-10-29 17:22:07 +00:00