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2011-02-15Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix text_poke_smp_batch() deadlock perf tools: Fix thread_map event synthesizing in top and record watchdog, nmi: Lower the severity of error messages ARM: oprofile: Fix backtraces in timer mode oprofile: Fix usage of CONFIG_HW_PERF_EVENTS for oprofile_perf_init and friends
2011-02-10ARM: 6654/1: perf/oprofile: fix off-by-one in stack checkRabin Vincent
Since tail is the previous fp - 1, we need to compare the new fp with tail + 1 to ensure that we don't end up passing in the same tail again, in order to avoid a potential infinite loop in the perf interrupt handler (which has been observed to occur). A similar fix seems to be needed in the OProfile code. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-01-26ARM: oprofile: Fix backtraces in timer modeAri Kauppi
Always allow backtraces when using oprofile on ARM, even if a PMU isn't present. Restores functionality originally introduced in commit 1b7b56982fdcd9d85effd76f3928cf5d6eb26155 ("oprofile: Always allow backtraces on ARM") by Richard Purdie. It is not that obvious, but there is now only one oprofile_arch_init() function. So the .backtrace callback is available also in timer mode. Implemented by removing code and using stubs for oprofile_perf_{init, exit} provided by <linux/oprofile.h>. This allows cleaning of other architecture specific implementations too. Cc: stable@kernel.org # 37.x Signed-off-by: Ari Kauppi <kauppi@papupata.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-10-11oprofile: Abstract the perf-events backendMatt Fleming
Move the perf-events backend from arch/arm/oprofile into drivers/oprofile so that the code can be shared between architectures. This allows each architecture to maintain only a single copy of the PMU accessor functions instead of one for both perf and OProfile. It also becomes possible for other architectures to delete much of their OProfile code in favour of the common code now available in drivers/oprofile/oprofile_perf.c. Signed-off-by: Matt Fleming <matt@console-pimps.org> Tested-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-10-11ARM: oprofile: Move non-ARM code into separate init/exitMatt Fleming
In preparation for moving the majority of this oprofile code into an architecture-neutral place separate the architecture-independent code into oprofile_perf_init() and oprofile_perf_exit(). Signed-off-by: Matt Fleming <matt@console-pimps.org> Tested-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-10-11ARM: oprofile: Rename op_arm to oprofile_perfMatt Fleming
In preparation for moving the generic functions out of this file, give the functions more general names (e.g. remove "arm" from the names). Signed-off-by: Matt Fleming <matt@console-pimps.org> Tested-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-10-11oprofile: Make op_name_from_perf_id() globalMatt Fleming
Make op_name_from_perf_id() global so that we have a way for each architecture to construct an oprofile name for op->cpu_type. We need to remove the argument from the function prototype so that we can hide all implementation details inside the function. Signed-off-by: Matt Fleming <matt@console-pimps.org> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-10-11perf: Add helper function to return number of countersMatt Fleming
The number of counters for the registered pmu is needed in a few places so provide a helper function that returns this number. Signed-off-by: Matt Fleming <matt@console-pimps.org> Tested-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-08-31oprofile, arm: initialize perf_event pointers with NULLRobert Richter
The pointers must be NULL'ed to avoid double-freeing the pointers in rare cases during reinitialization. Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-08-31ARM: oprofile: fix and simplify init/exit functionsWill Deacon
Now that oprofile_arch_exit is only called when the OProfile module is unloaded, it can assume that init completed successfully and not have to worry about double frees or releasing NULL perf events. This patch ensures that oprofile_arch_init fails gracefully on ARM and simplifies the exit code based on the above. Cc: Robert Richter <robert.richter@amd.com> Cc: Matt Fleming <matt@console-pimps.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-05-17ARM: 6074/1: oprofile: convert from sysdev to platform deviceWill Deacon
This is a reworking of an original patch posted by Aaro Koskinen: oprofile does not work with PM, because sysdev_suspend() is done with interrupts disabled and oprofile needs a mutex. Implementing oprofile as a platform device solves this problem. Cc: Aaro Koskinen <aaro.koskinen@nokia.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Aaro Koskinen <aaro.koskinen@nokia.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-05-17ARM: 6073/1: oprofile: remove old files and update KConfigWill Deacon
Enable hardware perf-events if CPU_HAS_PMU and select HAVE_OPROFILE if HAVE_PERF_EVENTS. If no hardware support is present, OProfile will fall back to timer mode. This patch also removes the old OProfile drivers in favour of the code implemented by perf. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-05-17ARM: 6072/1: oprofile: use perf-events framework as backendWill Deacon
There are currently two hardware performance monitoring subsystems in the kernel for ARM: OProfile and perf-events. This creates the following problems: 1.) Duplicate PMU accessor code. Inevitable code drift may lead to bugs in one framework that are fixed in the other. 2.) Locking issues. OProfile doesn't reprogram hardware counters between profiling runs if the events to be monitored have not been changed. This means that other profiling frameworks cannot use the counters if OProfile is in use. 3.) Due to differences in the two frameworks, it may not be possible to compare the results obtained by OProfile with those obtained by perf. This patch removes the OProfile PMU driver code and replaces it with calls to perf, therefore solving the issues mentioned above. The only userspace-visible change is the lack of SCU counter support for 11MPCore. This is currently unsupported by OProfile userspace tools anyway and therefore shouldn't cause any problems. Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Robert Richter <robert.richter@amd.com> Cc: Jamie Iles <jamie.iles@picochip.com> Cc: Jean Pihet <jpihet@mvista.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-02-12ARM: 5901/2: arm/oprofile: reserve the PMU when startingJamie Iles
Make sure that we have access to the performance counters and that they aren't being used by perf events or anything else. Cc: Will Deacon <will.deacon@arm.com> Cc: Jean Pihet <jpihet@mvista.com> Signed-off-by: Jamie Iles <jamie.iles@picochip.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-12-22ARM: 5849/1: ARMv7: fix Oprofile events countJean PIHET
On Oprofile ARMv7 the PMNC_D bit was set to lower the PMU IRQs and so to decrease the risk of errata #628216 from appearing. The effect of setting the PMNC_D bit is that the CCNT counter is divided by 64, making the program counter events count inaccurate. The new OMAP3 r4 cores should have that errata fixed. The PMNC_D bit should not be set, this patch fixes it. Signed-off-by: Jean Pihet <jpihet@mvista.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-10-17ARM: 5764/1: bcmring: add oprofile pmu supportLeo Chen
add oprofile pmu support for bcmring. Signed-off-by: Leo Hao Chen <leochen@broadcom.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-30RealView: Move the IRQ_* definitions out of the board-*.h filesCatalin Marinas
The IRQ_* macros need to be made visible via the mach/irqs.h file but without the additional macros defined in the board-*.h files. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2009-03-28Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-armLinus Torvalds
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (422 commits) [ARM] 5435/1: fix compile warning in sanity_check_meminfo() [ARM] 5434/1: ARM: OMAP: Fix mailbox compile for 24xx [ARM] pxa: fix the bad assumption that PCMCIA sockets always start with 0 [ARM] pxa: fix Colibri PXA300 and PXA320 LCD backlight pins imxfb: Fix TFT mode i.MX21/27: remove ifdef CONFIG_FB_IMX imxfb: add clock support mxc: add arch_reset() function clkdev: add possibility to get a clock based on the device name i.MX1: remove fb support from mach-imx [ARM] pxa: build arch/arm/plat-pxa/mfp.c only when PXA3xx or ARCH_MMP defined Gemini: Add support for Teltonika RUT100 Gemini: gpiolib based GPIO support v2 MAINTAINERS: add myself as Gemini architecture maintainer ARM: Add Gemini architecture v3 [ARM] OMAP: Fix compile for omap2_init_common_hw() MAINTAINERS: Add myself as Faraday ARM core variant maintainer ARM: Add support for FA526 v2 [ARM] acorn,ebsa110,footbridge,integrator,sa1100: Convert asm/io.h to linux/io.h [ARM] collie: fix two minor formatting nits ...
2009-02-12[ARM] 5382/1: unwind: Reorganise the stacktrace supportCatalin Marinas
This patch changes the walk_stacktrace and its callers for easier integration of stack unwinding. The arch/arm/kernel/stacktrace.h file is also moved to arch/arm/include/asm/stacktrace.h. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-01-12irq: update all arches for new irq_descMike Travis
Impact: cleanup, update to new cpumask API Irq_desc.affinity and irq_desc.pending_mask are now cpumask_var_t's so access to them should be using the new cpumask API. Signed-off-by: Mike Travis <travis@sgi.com>
2008-12-13cpumask: make irq_set_affinity() take a const struct cpumaskRusty Russell
Impact: change existing irq_chip API Not much point with gentle transition here: the struct irq_chip's setaffinity method signature needs to change. Fortunately, not widely used code, but hits a few architectures. Note: In irq_select_affinity() I save a temporary in by mangling irq_desc[irq].affinity directly. Ingo, does this break anything? (Folded in fix from KOSAKI Motohiro) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Reviewed-by: Grant Grundler <grundler@parisc-linux.org> Acked-by: Ingo Molnar <mingo@redhat.com> Cc: ralf@linux-mips.org Cc: grundler@parisc-linux.org Cc: jeremy@xensource.com Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
2008-09-06[ARM] Convert asm/io.h to linux/io.hRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-06[ARM] Convert asm/uaccess.h to linux/uaccess.hRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] 5195/1: ARMv7 Oprofile supportJean PIHET
Add Oprofile kernel support for ARMv7. Tested on OMAP3430 and OMAP3530 chipsets (Cortex-A8). Signed-off-by: Jean Pihet <jpihet@mvista.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-09-01[ARM] cputype: separate definitions, use themRussell King
Add asm/cputype.h, moving functions and definitions from asm/system.h there. Convert all users of 'processor_id' to the more efficient read_cpuid_id() function. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07[ARM] Move include/asm-arm/arch-* to arch/arm/*/include/machRussell King
This just leaves include/asm-arm/plat-* to deal with. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-07[ARM] Remove asm/hardware.h, use asm/arch/hardware.h insteadRussell King
Remove includes of asm/hardware.h in addition to asm/arch/hardware.h. Then, since asm/hardware.h only exists to include asm/arch/hardware.h, update everything to directly include asm/arch/hardware.h and remove asm/hardware.h. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-06-26smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe
It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-28[ARM] 5018/1: RealView: Fix the ARM11MPCore Oprofile compilationCatalin Marinas
This patch fixes the Oprofile for ARM11MPCore compilation introduced by changes to the RealView code. Only RealView/EB is supported. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-01-24Driver core: change sysdev classes to use dynamic kobject namesKay Sievers
All kobjects require a dynamically allocated name now. We no longer need to keep track if the name is statically assigned, we can just unconditionally free() all kobject names on cleanup. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-19Combine instrumentation menus in kernel/Kconfig.instrumentationMathieu Desnoyers
Quoting Randy: "It seems sad that this patch sources Kconfig.marker, a 7-line file, 20-something times. Yes, you (we) don't want to put those 7 lines into 20-something different files, so sourcing is the right thing. However, what you did for avr32 seems more on the right track to me: make _one_ Instrumentation support menu that includes PROFILING, OPROFILE, KPROBES, and MARKERS and then use (source) that in all of the arches." Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-02[ARM] Solve buggy smp_processor_id() usageRussell King
BUG: using smp_processor_id() in preemptible [00000001] code: opcontrol/427 Resolve this bug by ensuring that we're not using smp_processor_id() in a preemptable context (by disabling preemption.) Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-05-30[ARM] oprofile: avoid lockdep warnings on mpcore oprofile initRussell King
Fix lockdep warnings, caused by 'set_affinity' being called without the correct locks taken and local interrupts disabled: ================================= [ INFO: inconsistent lock state ] 2.6.22-rc2 #1 --------------------------------- inconsistent {in-hardirq-W} -> {hardirq-on-W} usage. swapper/1 [HC0[0]:SC0[0]:HE1:SE1] takes: (irq_controller_lock){++..}, at: [<c002be50>] gic_set_cpu+0x60/0xa0 {in-hardirq-W} state was registered at: [<c005d9a8>] lock_acquire+0x58/0x6c [<c0233068>] _spin_lock+0x40/0x50 [<c002c020>] gic_mask_irq+0x2c/0x6c [<c0069c64>] handle_level_irq+0x11c/0x14c [<c0020060>] asm_do_IRQ+0x60/0x84 [<c0020d2c>] __irq_svc+0x4c/0xc0 [<c000ed84>] __alloc_bootmem_nopanic+0x74/0x88 [<c000edb0>] __alloc_bootmem+0x18/0x3c [<c000fa00>] alloc_large_system_hash+0x16c/0x200 [<c00108dc>] inode_init_early+0x5c/0xa4 [<c00106dc>] vfs_caches_init_early+0x24/0xa0 [<c0008e54>] start_kernel+0x220/0x2fc [<00008078>] 0x8078 irq event stamp: 88438 hardirqs last enabled at (88438): [<c0020dc0>] preempt_return+0x20/0x2c hardirqs last disabled at (88436): [<c00417bc>] __do_softirq+0xb0/0x138 softirqs last enabled at (88437): [<c0041810>] __do_softirq+0x104/0x138 softirqs last disabled at (88428): [<c0041d9c>] irq_exit+0x68/0x7c other info that might help us debug this: no locks held by swapper/1. stack backtrace: [<c0025ecc>] (dump_stack+0x0/0x14) from [<c005b1e4>] (print_usage_bug+0x138/0x168) [<c005b0ac>] (print_usage_bug+0x0/0x168) from [<c005be80>] (mark_lock+0x484/0x6a0) [<c005b9fc>] (mark_lock+0x0/0x6a0) from [<c005cc48>] (__lock_acquire+0x3c0/0x10c8) [<c005c888>] (__lock_acquire+0x0/0x10c8) from [<c005d9a8>] (lock_acquire+0x58/0x6c) [<c005d950>] (lock_acquire+0x0/0x6c) from [<c0233068>] (_spin_lock+0x40/0x50) [<c0233028>] (_spin_lock+0x0/0x50) from [<c002be50>] (gic_set_cpu+0x60/0xa0) [<c002bdf0>] (gic_set_cpu+0x0/0xa0) from [<c01b04cc>] (em_route_irq+0x38/0x40) [<c01b0494>] (em_route_irq+0x0/0x40) from [<c01b04ec>] (em_setup+0x18/0xa4) [<c01b04d4>] (em_setup+0x0/0xa4) from [<c001570c>] (oprofile_arch_init+0x24/0xe8) [<c00156e8>] (oprofile_arch_init+0x0/0xe8) from [<c0015640>] (oprofile_init+0x1c/0x64) [<c0015624>] (oprofile_init+0x0/0x64) from [<c0008a20>] (kernel_init+0x154/0x368) [<c00088cc>] (kernel_init+0x0/0x368) from [<c003ef34>] (do_exit+0x0/0x904) oprofile: using arm/mpcore Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-04-28[ARM] Add stacktrace support and make oprofile use itRussell King
Add support for stacktrace. Use the new stacktrace code with oprofile instead of it's version; there's no point having multiple versions of stacktracing in the kernel. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-03-02[ARM] 4237/2: oprofile: Always allow backtraces on ARMRichard Purdie
Always allow backtrace when using oprofile on ARM, even if a PMU isn't present. Signed-off-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-06[ARM] oprofile: add ARM11 SMP supportRussell King
Add the glue for ARM11 SMP oprofile support, which also supports the performance monitor in the coherency unit. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-06[ARM] oprofile: add ARM11 UP supportRussell King
Add oprofile glue for ARM11 (ARMv6) oprofile support. This connects the ARM11 core profiling support to the oprofile code for uniprocessor configurations. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2007-02-06[ARM] oprofile: add ARM11 core supportRussell King
Add basic support for the ARM11 profiling hardware. This is shared between the ARM11 UP and ARM11 SMP oprofile support code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-14[ARM] Remove OP_MAX_COUNTERRussell King
OP_MAX_COUNTER never referenced, and is a reminant of an earlier oprofile implementation. Remove it. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-10-15[ARM] Fix fallout from IRQ regs changesRussell King
Some ARM platforms were still broken as a result of the IRQ register passing changes, mostly due to a missing linux/irq.h include. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-10-06Initial blind fixup for arm for irq changesLinus Torvalds
Untested, but this should fix up the bulk of the totally mechanical issues, and should make the actual detail fixing easier. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-30[ARM] 3880/1: remove the last trace of iop31x supportLennert Buytenhek
Remove the last trace of iop31x support from the kernel. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-09-25[ARM] 3832/1: iop3xx: coding style cleanupLennert Buytenhek
Since the iop32x code isn't iop321-specific, and the iop33x code isn't iop331-specfic, do a s/iop321/iop32x/ and s/iop331/iop33x/, and tidy up the code to conform to the coding style guidelines somewhat better. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-09-25[ARM] 3816/1: iop3xx: rename config symbolsLennert Buytenhek
Rename CONFIG_ARCH_IOP321 to CONFIG_ARCH_IOP32X and CONFIG_ARCH_IOP331 to CONFIG_ARCH_IOP33X. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-07-02[PATCH] ARM: fixup irqflags breakage after ARM genirq mergeThomas Gleixner
The irgflags consolidation did conflict with the ARM to generic IRQ conversion and was not applied for ARM. Fix it up. Use the new IRQF_ constants and remove the SA_INTERRUPT define Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-21[ARM] Use kcalloc to allocate counter_config array rather than kmallocRussell King
We need this to be zero initialised. Since this is an array, use kcalloc rather than kzalloc or kmalloc. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-21[ARM] Oprofile: dynamically allocate counter_configRussell King
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-03-21[ARM] Oprofile: Convert semaphore to mutexRussell King
op_arm_sem is being used as a mutex, so convert it to use real mutexes. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-02-01[ARM] 3295/1: Fix oprofile init return valueRuss Dill
Patch from Russ Dill The oprofile init code was broken in commit c6b9da. The new logic will always return -ENODEV. This fixes oprofile_arch_init to return 0 on success, and return the return value of spec->init() if applicable. Signed-off-by: Russ Dill <Russ.Dill@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-29[PATCH] mm: kill check_user_page_readableHugh Dickins
check_user_page_readable is a problematic variant of follow_page. It's used only by oprofile's i386 and arm backtrace code, at interrupt time, to establish whether a userspace stackframe is currently readable. This is problematic, because we want to push the page_table_lock down inside follow_page, and later split it; whereas oprofile is doing a spin_trylock on it (in the i386 case, forgotten in the arm case), and needs that to pin perhaps two pages spanned by the stackframe (which might be covered by different locks when we split). I think oprofile is going about this in the wrong way: it doesn't need to know the area is readable (neither i386 nor arm uses read protection of user pages), it doesn't need to pin the memory, it should simply __copy_from_user_inatomic, and see if that succeeds or not. Sorry, but I've not got around to devising the sparse __user annotations for this. Then we can eliminate check_user_page_readable, and return to a single follow_page without the __follow_page variants. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>