If we are not changing the control register value, avoid writing to it.
Writes to the control register can be very expensive, taking around a
hundred cycles or so.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Use the more common pr_warn.

Other miscellanea:

o Coalesce formats
o Realign arguments
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

After becoming a mandatory function, boot_secondary() is no longer used
outside arch/arm/kernel/smp.c. Hence remove its public prototype, and,
as suggested by Arnd, let it be absorbed by its single caller.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add the memfd_create syscall to ARM.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add the new getrandom syscall for ARM.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The strings used to list IPIs in /proc/interrupts are reused for tracing
purposes.

While at it, prevent a negative ipinr from escaping the range check
in handle_IPI().

Link: http://lkml.kernel.org/p/1406318733-26754-4-git-send-email-nicolas.pitre@linaro.orgAcked-by: NDaniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

The kgdb breakpoint hooks (kgdb_brk_fn and kgdb_compiled_brk_fn)
should only be entered when a kgdb break instruction is executed
from the kernel. Otherwise, if kgdb is enabled, a userspace program
can cause the kernel to drop into the debugger by executing either
KGDB_BREAKINST or KGDB_COMPILED_BREAK.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

With SCU standby enabled, SCU CLK will be turned off when all processors
are in WFI mode.  And the clock will be turned on when any processor
leaves WFI mode.

This behavior should be preferable in terms of power efficiency of
system idle.  So let's set the SCU standby bit to enable the support in
function scu_enable().

Cortex-A9 earlier than r2p0 has no standby bit in SCU, so we need to
skip setting the bit for those.
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>
Acked-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Use macro instead of magic number for SCU enable bit.
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>
Acked-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Commit 1c2f87c2
(ARM: 8025/1: Get rid of meminfo) dropped the upper bound on
the number of memory banks that can be added as there was no
technical need in the kernel. It turns out though, some bootloaders
(specifically the arndale-octa exynos boards) may pass invalid memory
information and rely on the kernel to not parse this data. This is a
bug in the bootloader but we still need to work around this.
Work around this by introducing a dt_fixup function. This function
gets called before the flattened devicetree is scanned for memory
and the like. In this fixup function for exynos, limit the maximum
number of memory regions in the devicetree.
Signed-off-by: NLaura Abbott <lauraa@codeaurora.org>
Tested-by: NAndreas Färber <afaerber@suse.de>
[glikely: Added a comment and fixed up function name]
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Broadcom Brahma-B15 (r0p0..r0p2) is also affected by Cortex-A15
erratum 798181, so enable the workaround for Brahma-B15.
Signed-off-by: NGregory Fong <gregory.0xf0@gmail.com>
Acked-by: NMarc Carino <marc.ceeeee@gmail.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Wires up the new seccomp syscall.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NOleg Nesterov <oleg@redhat.com>

commit 431a84b1
 ("ARM: 8034/1: Disable preemption in iwmmxt_task_enable()")
introduced macros {inc,dec}_preempt_count to iwmmxt_task_enable
to make it run with preemption disabled.

Unfortunately, other functions in iwmmxt.S also use concan_{save,dump,load}
sections located in iwmmxt_task_enable() to deal with iWMMXt coprocessor.
This causes an unbalanced preempt_count due to excessive dec_preempt_count
and destroyed return addresses in callers of concan_ labels due to a register
collision:

Linux version 3.16.0-rc3-00062-gd92a333a-dirty (jef@armhf) (gcc version 4.8.3 (Debian 4.8.3-4) ) #5 PREEMPT Thu Jul 3 19:46:39 CEST 2014
CPU: ARMv7 Processor [560f5815] revision 5 (ARMv7), cr=10c5387d
CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
Machine model: SolidRun CuBox
...
PJ4 iWMMXt v2 coprocessor enabled.
...
Unable to handle kernel paging request at virtual address fffffffe
pgd = bb25c000
[fffffffe] *pgd=3bfde821, *pte=00000000, *ppte=00000000
Internal error: Oops: 80000007 [#1] PREEMPT ARM
Modules linked in:
CPU: 0 PID: 62 Comm: startpar Not tainted 3.16.0-rc3-00062-gd92a333a-dirty #5
task: bb230b80 ti: bb256000 task.ti: bb256000
PC is at 0xfffffffe
LR is at iwmmxt_task_copy+0x44/0x4c
pc : [<fffffffe>]    lr : [<800130ac>]    psr: 40000033
sp : bb257de8  ip : 00000013  fp : bb257ea4
r10: bb256000  r9 : fffffdfe  r8 : 76e898e6
r7 : bb257ec8  r6 : bb256000  r5 : 7ea12760  r4 : 000000a0
r3 : ffffffff  r2 : 00000003  r1 : bb257df8  r0 : 00000000
Flags: nZcv  IRQs on  FIQs on  Mode SVC_32  ISA Thumb  Segment user
Control: 10c5387d  Table: 3b25c019  DAC: 00000015
Process startpar (pid: 62, stack limit = 0xbb256248)

This patch fixes the issue by moving concan_{save,dump,load} into separate
code sections and make iwmmxt_task_enable() call them in the same way the
other functions use concan_ symbols. The test for valid ownership is moved
to concan_save and is safe for the other user of it, iwmmxt_task_disable().
The register collision is also resolved by moving concan_ symbols as
{inc,dec}_preempt_count are now local to iwmmxt_task_enable().

Fixes: 431a84b1 ("ARM: 8034/1: Disable preemption in iwmmxt_task_enable()")
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Reported-by: NJean-Francois Moine <moinejf@free.fr>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

When the CPU has support for the byte and word exclusive operations,
userspace should use them in preference to the SWP instructions.
Detect the presence of these instructions by reading the ISAR CPU ID
registers and adjust the ELF HWCAP mask appropriately.

Note that ARM1136 < r1p0 has no ISAR4, so this is explicitly detected
and the test disabled, leaving the current situation where HWCAP_SWP
is set.
Tested-by: NTony Lindgren <tony@atomide.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Previous CPUs do not have the ability to trap SWP instructions, so
it's pointless initialising this code there.
Tested-by: NTony Lindgren <tony@atomide.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Commit 78d7530a ("ARM: Clean up linker script using new linker script
macros.") modified the arm kernel linker script to use the STABS_DEBUG
macro, but left a .comment section definition. As STABS_DEBUG defines
the .comment section in an identical way, the second section definition
is redundant and can be removed.

This patch removes the redundant .comment section definition.
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Use the newly-introduced frame_pointer macro to extract
the correct FP based on whether we are in THUMB2 mode or not.
Signed-off-by: NNikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Make the unwind code use the correct API so that the frame pointer
is extracted from the correct register.
Signed-off-by: NNikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Make use of the arm_get_current_stackframe api so that
the frame pointer is correctly referenced in THUMB2 mode
Signed-off-by: NNikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Make the perf backend use the API so that it correctly references the FP
when in THUMB2 mode
Signed-off-by: NNikolay Borisov <Nikolay.Borisov@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls.  Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).

We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.

Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code.  This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: NWill Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Ensure that platform maintainers check the CPU part number in the right
manner: the CPU part number is meaningless without also checking the
CPU implement(e|o)r (choose your preferred spelling!)  Provide an
interface which returns both the implementer and part number together,
and update the definitions to include the implementer.

Mark the old function as being deprecated... indeed, using the old
function with the definitions will now always evaluate as false, so
people must update their un-merged code to the new function.  While
this could be avoided by adding new definitions, we'd also have to
create new names for them which would be awkward.
Acked-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

HSCTLR.EE is defined as bit[25] referring to arm manual
DDI0606C.b(p1590).
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NLi Liu <john.liuli@huawei.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

In order to make way for the GICv3 registers, move the v2-specific
registers to their own structure.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: NChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>

Under perf, the fp unwinding scheme requires access to user space memory
and can provoke a pagefault via call to __copy_from_user_inatomic from
user_backtrace. This unwinding can take place in response to an interrupt
(__perf_event_overflow). This is undesirable as we may already have
mmap_sem held for write. One example being a process that calls mprotect
just as a the PMU counters overflow.

An example that can provoke this behaviour:
perf record -e event:tocapture --call-graph fp ./application_to_test

This patch addresses this issue by disabling pagefaults briefly in
user_backtrace (as is done in the other architectures: ARM64, x86, Sparc etc.).

Without the patch a deadlock occurs when __perf_event_overflow is called
while reading the data from the user space:

 [ INFO: possible recursive locking detected ]
 3.16.0-rc2-00038-g0ed7ff6 #46 Not tainted
 ---------------------------------------------
 stress/1634 is trying to acquire lock:
 (&mm->mmap_sem){++++++}, at: [<c001dc04>] do_page_fault+0xa8/0x428

 but task is already holding lock:
 (&mm->mmap_sem){++++++}, at: [<c00f4098>] SyS_mprotect+0xa8/0x1c8

 other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&mm->mmap_sem);
  lock(&mm->mmap_sem);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

 2 locks held by stress/1634:
 #0:  (&mm->mmap_sem){++++++}, at: [<c00f4098>] SyS_mprotect+0xa8/0x1c8
 #1:  (rcu_read_lock){......}, at: [<c00c29dc>] __perf_event_overflow+0x120/0x294

 stack backtrace:
 CPU: 1 PID: 1634 Comm: stress Not tainted 3.16.0-rc2-00038-g0ed7ff6 #46
 [<c0017c8c>] (unwind_backtrace) from [<c0012eec>] (show_stack+0x20/0x24)
 [<c0012eec>] (show_stack) from [<c04de914>] (dump_stack+0x7c/0x98)
 [<c04de914>] (dump_stack) from [<c006a360>] (__lock_acquire+0x1484/0x1cf0)
 [<c006a360>] (__lock_acquire) from [<c006b14c>] (lock_acquire+0xa4/0x11c)
 [<c006b14c>] (lock_acquire) from [<c04e3880>] (down_read+0x40/0x7c)
 [<c04e3880>] (down_read) from [<c001dc04>] (do_page_fault+0xa8/0x428)
 [<c001dc04>] (do_page_fault) from [<c00084ec>] (do_DataAbort+0x44/0xa8)
 [<c00084ec>] (do_DataAbort) from [<c0013a1c>] (__dabt_svc+0x3c/0x60)
 Exception stack(0xed7c5ae0 to 0xed7c5b28)
 5ae0: ed7c5b5c b6dadff4 ffffffec 00000000 b6dadff4 ebc08000 00000000 ebc08000
 5b00: 0000007e 00000000 ed7c4000 ed7c5b94 00000014 ed7c5b2c c001a438 c0236c60
 5b20: 00000013 ffffffff
 [<c0013a1c>] (__dabt_svc) from [<c0236c60>] (__copy_from_user+0xa4/0x3a4)
Acked-by: NSteve Capper <steve.capper@linaro.org>
Signed-off-by: NJean Pihet <jean.pihet@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

An event may occur when an mm is already released.

As per commit 20afc60f
 'x86, perf: Check that current->mm is alive before getting user callchain'
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NJean Pihet <jean.pihet@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Currently the krait_pmu_{enable,disable}_event functions use the global
cpu_pmu variable while all the other pmu enable/disable functions
derive this from the event argument.

This patch brings the Krait functions into line with the rest of the PMU
backends by deriving the address of the pmu from the event argument.
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NStephen Boyd <sboyd@codeaurora.org>
Tested-by: NChristopher Covington <cov@codeaurora.org>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

When described in DT, PMUs are given specific compatible strings
(e.g. "arm,cortex-a15-pmu") which makes it very easy to reorganise the
way individual PMUs are handled (i.e. we can easily split them into
separate drivers). The same is not true of PMUs described in board
files, which are all use the platform_device_id "arm-pmu" and must all
be handled by the same driver.

To enable splitting the ARMv6, ARMv7, and XScale PMU drivers we need
board files to identify which variant they provide. As a first step,
this patch adds new platform_device_id values: "armv6-pmu", "armv7-pmu,
and "xscale-pmu".

Once board files are moved over and all existing uses of "arm-pmu" are
gone, we can split the existing driver apart.
Acked-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NChristopher Covington <cov@codeaurora.org>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

The perf userspace tools can't handle dashes or spaces in PMU names,
which conflicts with the current naming scheme in the arm perf backend.
This prevents these PMUs from being accessed by name from the perf
tools. Additionally the ARMv6 pmus are named "v6", which does not fully
distinguish them in the sys/bus/event_source namespace.

This patch renames the PMUs consistently to a lower case form with
underscores, e.g. "armv6_1176", "armv7_cortex_a9". This is both readily
accepted by today's perf tool, and far easier to type than the
(apparently unused) convention in use previously. The OProfile name
conversion code is updated to handle this.

Due to a copy-paste error involving two "xscale1" entries, "xscale2" has
never been matched by the name OProfile name mapping. While we're
updating names, this is corrected.
Acked-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NChristopher Covington <cov@codeaurora.org>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
[sachin: fixed missing semicolons in armv6 backend]
Signed-off-by: NSachin Kamat <sachin.kamat@samsung.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Now that we have macros for declaring fully invalid event maps, put them
to work for the XScale PMU event maps. While this necessitates repeating
common indices, we no longer need to refer to *_UNSUPPORTED events at
all, and it makes it possible for the even maps to fit on a single page
on a reasonably sized monitor.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Now that we have macros for declaring fully invalid event maps, put them
to work for all the ARMv6 PMU event maps. While this necessitates
repeating common indices, we no longer need to refer to *_UNSUPPORTED
events at all, and it makes it possible for the even maps to fit on a
single page on a reasonably sized monitor.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Now that we have macros for declaring fully invalid event maps, put them
to work for all the ARMv7 PMU event maps. While this necessitates
repeating common indices, we no longer need to refer to *_UNSUPPORTED
events at all, and it makes it possible for the even maps to fit on a
single page on a reasonably sized monitor.
Acked-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NChristopher Covington <cov@codeaurora.org>
Signed-off-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Conditionally compile kprobes test cases for ARMv5 instructions to avoid
compilation errors with ARMv4 targets like:

/tmp/cc7Tx8ST.s:16740: Error: selected processor does not support ARM mode `clz r0,r0'
Signed-off-by: NJon Medhurst <tixy@linaro.org>

ARM data processing instructions which have a register specified shift
are defined as UNPREDICTABLE if PC is used for any register, not just
the shift value as the code was previous assuming. This issue manifests
on A15 devices as either test case failures or undefined instructions
aborts.
Reported-by: NDavid Long <dave.long@linaro.org>
Signed-off-by: NJon Medhurst <tixy@linaro.org>

Due to a long-standing issue with Thumb symbol lookup [1] the jprobes
tests fail when built into a kernel compiled as Thumb mode. (They work
fine for ARM mode kernels or for Thumb when built as a loadable module.)

Rather than have this problem terminate testing prematurely lets instead
emit an error message and carry on with the main kprobes tests, delaying
the final failure report until the end.

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2011-August/063026.htmlSigned-off-by: NJon Medhurst <tixy@linaro.org>

Commit 143e1e28 (sched: Rework sched_domain topology definition)
introduced a number of functions with a return value of 'const int'.
gcc doesn't know what to do with that and, if the kernel is compiled
with W=1, complains with the following warnings whenever sched.h
is included.

  include/linux/sched.h:875:25: warning: type qualifiers ignored on function return type
  include/linux/sched.h:882:25: warning: type qualifiers ignored on function return type
  include/linux/sched.h:889:25: warning: type qualifiers ignored on function return type
  include/linux/sched.h:1002:21: warning: type qualifiers ignored on function return type

Commits fb2aa855 (sched, ARM: Create a dedicated scheduler topology table)
and 607b45e9 (sched, powerpc: Create a dedicated topology table) introduce
the same warning in the arm and powerpc code.

Drop 'const' from the function declarations to fix the problem.

The fix for all three patches has to be applied together to avoid
compilation failures for the affected architectures.
Acked-by: NVincent Guittot <vincent.guittot@linaro.org>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1403658329-13196-1-git-send-email-linux@roeck-us.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

On the syscall tracing path, we call out to secure_computing() to allow
seccomp to check the syscall number being attempted. As part of this, a
SIGTRAP may be sent to the tracer and the syscall could be re-written by
a subsequent SET_SYSCALL ptrace request. Unfortunately, this new syscall
is ignored by the current code unless TIF_SYSCALL_TRACE is also set on
the current thread.

This patch slightly reworks the enter path of the syscall tracing code
so that we always reload the syscall number from
current_thread_info()->syscall after the potential ptrace traps.
Acked-by: NKees Cook <keescook@chromium.org>
Tested-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

GCC 4.6.4 spits out the following warning when building perf_event_v7.c:

arch/arm/kernel/perf_event_v7.c: In function 'krait_pmu_get_event_idx':
arch/arm/kernel/perf_event_v7.c:1927:6: warning: 'bit' may be used uninitialized in this function

While upgrading the version of gcc may solve this, the code can also be
organised to be more efficient by not carrying more local variables than
is necessary across the armv7pmu_get_event_idx function call.  If we set
'bit' to -1 (which is invalid for clear_bit) we can use that as an
indication whether we need to clear a bit after this function.
Acked-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch to prevent warning of a buggy compiler when using clang and
the ARM_UNWIND option.

Clang defines (at least on the current trunk) GNUC, GNUC_MINOR, and
GNUC_PATCHLEVEL to 4, 2, and 1 respectively.

This version of GCC gets flagged as buggy, but it isn't actually an
issue with clang so the patch will do what it did before unless clang
is defined and then it will not report the GCC version as an issue.
Signed-off-by: NMark Charlebois <charlebm@gmail.com>
Signed-off-by: NBehan Webster <behanw@converseincode.com>

This typedef is unnecessary and should just be removed.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>