Use cpu compatibility field and clock-frequency field of DT to
estimate the capacity of each core of the system and to update
the cpu_power field accordingly.
This patch enables to put more running tasks on big cores than
on LITTLE ones. But this patch doesn't ensure that long running
tasks will run on big cores and short ones on LITTLE cores.
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This factorization has also been proposed in another patch that has not been
merged yet:
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-January/080873.html
So, this patch could be dropped depending of the state of the other one.
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add infrastructure to be able to modify the cpu_power of each core
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: NNamhyung Kim <namhyung@kernel.org>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The syscall_trace on ARM takes a `why' parameter to indicate whether or
not we are entering or exiting a system call. This can be confusing for
people looking at the code since (a) it conflicts with the why register
alias in the entry assembly code and (b) it is not immediately clear
what it represents.

This patch splits up the syscall_trace function into separate wrappers
for syscall entry and exit, allowing the low-level syscall handling
code to branch to the appropriate function.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

When auditing system calls on ARM, the audit code is called before
notifying the parent process in the case that the current task is being
ptraced. At this point, the parent (debugger) may choose to change the
system call being issued via the SET_SYSCALL ptrace request, causing
the wrong system call to be reported to the audit tools.

This patch moves the audit calls after the ptrace SIGTRAP handling code
in the syscall tracing implementation.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ret_from_fork is setup for a freshly spawned child task via copy_thread,
called from copy_process. The latter function clears TIF_SYSCALL_TRACE
and also resets the child task's audit_context to NULL, meaning that
there is little point invoking the system call tracing routines.
Furthermore, getting hold of the syscall number is a complete pain and
it looks like the current code doesn't even bother.

This patch removes the syscall tracing checks from ret_from_fork.
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch allows a timer-based delay implementation to be selected by
switching the delay routines over to use get_cycles, which is
implemented in terms of read_current_timer. This further allows us to
skip the loop calibration and have a consistent delay function in the
face of core frequency scaling.

To avoid the pain of dealing with memory-mapped counters, this
implementation uses the co-processor interface to the architected timers
when they are available. The previous loop-based implementation is
kept around for CPUs without the architected timers and we retain both
the maximum delay (2ms) and the corresponding conversion factors for
determining the number of loops required for a given interval. Since the
indirection of the timer routines will only work when called from C,
the sa1100 sleep routines are modified to branch to the loop-based delay
functions directly.
Tested-by: NShinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch implements read_current_timer using the architected timers
when they are selected via CONFIG_ARM_ARCH_TIMER. If they are detected
not to be usable at runtime, we return -ENXIO to the caller.

Furthermore, if read_current_timer is exported then we can implement
get_cycles in terms of it for use as both an entropy source and for
implementing __udelay and friends.
Tested-by: NShinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch implements the word-at-a-time interface for ARM using the
same algorithm as x86. We use the fls macro from ARMv5 onwards, where
we have a clz instruction available which saves us a mov instruction
when targetting Thumb-2. For older CPUs, we use the magic 0x0ff0001
constant. Big-endian configurations make use of the implementation from
asm-generic.

With this implemented, we can replace our byte-at-a-time strnlen_user
and strncpy_from_user functions with the optimised generic versions.
Reviewed-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

In order to provide PMU name strings compatible with the OProfile
user ABI, an enumeration of all PMUs is currently used by perf to
identify each PMU uniquely. Unfortunately, this does not scale well
in the presence of multiple PMUs and creates a single, global namespace
across all PMUs in the system.

This patch removes the enumeration and instead uses the name string
for the PMU to map onto the OProfile variant. perf_pmu_name is
implemented for CPU PMUs, which is all that OProfile cares about anyway.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

When a CPU is shutdown its architected timer comparators registers are
lost. Within CPU idle, before processors enter shutdown they enter
clock events broadcast mode through the

clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, cpuid);

function where the local timers are emulated by a global always-on timer.
On CPU resume, the per-CPU tick device normal mode is restored by exiting
broadcast mode through

clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, cpuid);

In order for this mechanism to function, architected timers should add to
their feature C3STOP, which means that they are not able to function when the
CPU is in off-mode.
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Let's map the initial RAM up to the end of the kernel .bss instead of
the strict kernel image area.  This simplifies the code as the kernel
image only needs to be handled specially in the XIP case.  That covers
the legacy ATAG location as well.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Robustify ARM's die() handling with improvements from x86:

 - Fix for a deadlock (before panic in the case of panic_on_oops) if we
   oops under a spinlock which is also used from interrupt handler,
   since the old code was unconditionally enabling interrupts.

 - Usage of arch spinlock so lockdep etc doesn't get involved while
   we're trying to dump out oopses.

 - Deadlock prevention in the unlikely event that die() recurses.

The changes all touch the same few lines of code, so they're done
together in one patch.
Signed-off-by: NRabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

While running hotplug tests I ran into this RCU splat

===============================
[ INFO: suspicious RCU usage. ]
3.4.0 #3275 Tainted: G        W
-------------------------------
include/linux/rcupdate.h:729 rcu_read_lock() used illegally while idle!

other info that might help us debug this:

RCU used illegally from idle CPU!
rcu_scheduler_active = 1, debug_locks = 0
RCU used illegally from extended quiescent state!
4 locks held by swapper/2/0:
 #0:  ((cpu_died).wait.lock){......}, at: [<c00ab128>] complete+0x1c/0x5c
 #1:  (&p->pi_lock){-.-.-.}, at: [<c00b275c>] try_to_wake_up+0x2c/0x388
 #2:  (&rq->lock){-.-.-.}, at: [<c00b2860>] try_to_wake_up+0x130/0x388
 #3:  (rcu_read_lock){.+.+..}, at: [<c00abe5c>] cpuacct_charge+0x28/0x1f4

stack backtrace:
[<c001521c>] (unwind_backtrace+0x0/0x12c) from [<c00abec8>] (cpuacct_charge+0x94/0x1f4)
[<c00abec8>] (cpuacct_charge+0x94/0x1f4) from [<c00b395c>] (update_curr+0x24c/0x2c8)
[<c00b395c>] (update_curr+0x24c/0x2c8) from [<c00b59c4>] (enqueue_task_fair+0x50/0x194)
[<c00b59c4>] (enqueue_task_fair+0x50/0x194) from [<c00afea4>] (enqueue_task+0x30/0x34)
[<c00afea4>] (enqueue_task+0x30/0x34) from [<c00b0908>] (ttwu_activate+0x14/0x38)
[<c00b0908>] (ttwu_activate+0x14/0x38) from [<c00b28a8>] (try_to_wake_up+0x178/0x388)
[<c00b28a8>] (try_to_wake_up+0x178/0x388) from [<c00a82a0>] (__wake_up_common+0x34/0x78)
[<c00a82a0>] (__wake_up_common+0x34/0x78) from [<c00ab154>] (complete+0x48/0x5c)
[<c00ab154>] (complete+0x48/0x5c) from [<c07db7cc>] (cpu_die+0x2c/0x58)
[<c07db7cc>] (cpu_die+0x2c/0x58) from [<c000f954>] (cpu_idle+0x64/0xfc)
[<c000f954>] (cpu_idle+0x64/0xfc) from [<80208160>] (0x80208160)

When a cpu is marked offline during its idle thread it calls
cpu_die() during an RCU idle period. cpu_die() calls complete()
to notify the killing process that the cpu has died. complete()
calls into the scheduler code and eventually grabs an RCU read
lock in cpuacct_charge().

Mark complete() as RCU_NONIDLE so that RCU pays attention to this
CPU for the duration of the complete() function even though it's
in idle.
Suggested-by: N"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

'sub pc, pc, #1b-2b+8-2' results in address<1:0> == '10'.

sub pc, pc, #const (== ADR pc, #const) performs an interworking branch
(BXWritePC()) on ARMv7+ and a simple branch (BranchWritePC()) on earlier
versions.

In ARM state, BXWritePC() is UNPREDICTABLE when address<1:0> == '10'.

In ARM state on ARMv6+, BranchWritePC() ignores address<1:0>.  Before
ARMv6, BranchWritePC() is UNPREDICTABLE if address<1:0> != '00'

So the instruction is UNPREDICTABLE both before and after v6.
Acked-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NRabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

We currently return -EPERM if the user requests mode exclusion that is
not supported by the CPU. This looks pretty confusing from userspace
and is inconsistent with other architectures (ppc, x86).

This patch returns -EOPNOTSUPP instead.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This reverts commit 6b5c8045.

Conflicts:

	arch/arm/kernel/ptrace.c

The new syscall restarting code can lead to problems if we take an
interrupt in userspace just before restarting the svc instruction. If
a signal is delivered when returning from the interrupt, the
TIF_SYSCALL_RESTARTSYS will remain set and cause any syscalls executed
from the signal handler to be treated as a restart of the previously
interrupted system call. This includes the final sigreturn call, meaning
that we may fail to exit from the signal context. Furthermore, if a
system call made from the signal handler requires a restart via the
restart_block, it is possible to clear the thread flag and fail to
restart the originally interrupted system call.

The right solution to this problem is to perform the restarting in the
kernel, avoiding the possibility of handling a further signal before the
restart is complete. Since we're almost at -rc6, let's revert the new
method for now and aim for in-kernel restarting at a later date.
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This reverts commit fa18484d.

We need the restart trampoline back so that we can revert a related
problematic patch 6b5c8045 ("arm: new
way of handling ERESTART_RESTARTBLOCK").
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ARM builds seem to be plagued by an occasional build error:

    Inconsistent kallsyms data
    This is a bug - please report about it
    Try "make KALLSYMS_EXTRA_PASS=1" as a workaround

The problem has to do with alignment of some sections by the linker.
The kallsyms data is built in two passes by first linking the kernel
without it, and then linking the kernel again with the symbols
included.  Normally, this just shifts the symbols, without changing
their order, and the compression used by the kallsyms gives the same
result.

On non SMP, the per CPU data is empty.  Depending on the where the
alignment ends up, it can come out as either:

   +-------------------+
   | last text segment |
   +-------------------+
   /* padding */
   +-------------------+     <- L1_CACHE_BYTES alignemnt
   | per cpu (empty)   |
   +-------------------+
__per_cpu_end:
   /* padding */
__data_loc:
   +-------------------+     <- THREAD_SIZE alignment
   | data              |
   +-------------------+

or

   +-------------------+
   | last text segment |
   +-------------------+
   /* padding */
   +-------------------+     <- L1_CACHE_BYTES alignemnt
   | per cpu (empty)   |
   +-------------------+
__per_cpu_end:
   /* no padding */
__data_loc:
   +-------------------+     <- THREAD_SIZE alignment
   | data              |
   +-------------------+

if the alignment satisfies both.  Because symbols that have the same
address are sorted by 'nm -n', the second case will be in a different
order than the first case.  This changes the compression, changing the
size of the kallsym data, causing the build failure.

The KALLSYMS_EXTRA_PASS=1 workaround usually works, but it is still
possible to have the alignment change between the second and third
pass.  It's probably even possible for it to never reach a fixedpoint.

The problem only occurs on non-SMP, when the per-cpu data is empty,
and when the data segment has alignment (and immediately follows the
text segments).  Fix this by only including the per_cpu section on
SMP, when it is not empty.
Signed-off-by: NDavid Brown <davidb@codeaurora.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fixup entries in the kernel exception tables should be 4-byte aligned
since we return directly to them when handling a faulting instruction in
the kernel.

This patch adds the missing align directives to the fixup entries.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

t32_simulate_ldr_literal() can be run without an instruction slot, so it
should be using DECODE_SIMULATEX instead of DECODE_EMULATEX.
Acked-by: NJon Medhurst <tixy@yxit.co.uk>
Signed-off-by: NRabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Does block_sigmask() + tracehook_signal_handler();  called when
sigframe has been successfully built.  All architectures converted
to it; block_sigmask() itself is gone now (merged into this one).

I'm still not too happy with the signature, but that's a separate
story (IMO we need a structure that would contain signal number +
siginfo + k_sigaction, so that get_signal_to_deliver() would fill one,
signal_delivered(), handle_signal() and probably setup...frame() -
take one).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Only 3 out of 63 do not.  Renamed the current variant to __set_current_blocked(),
added set_current_blocked() that will exclude unblockable signals, switched
open-coded instances to it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

replace boilerplate "should we use ->saved_sigmask or ->blocked?"
with calls of obvious inlined helper...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

first fruits of ..._restore_sigmask() helpers: now we can take
boilerplate "signal didn't have a handler, clear RESTORE_SIGMASK
and restore the blocked mask from ->saved_mask" into a common
helper.  Open-coded instances switched...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Checking for process->mm is not enough because process' main thread may
exit or detach its mm via use_mm(), but other threads may still have a
valid mm.

To fix this we would need to use find_lock_task_mm(), which would walk up
all threads and returns an appropriate task (with task lock held).

clear_tasks_mm_cpumask() has this issue fixed, so let's use it.
Suggested-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NAnton Vorontsov <anton.vorontsov@linaro.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

guts of saved_sigmask-based sigsuspend/rt_sigsuspend.  Takes
kernel sigset_t *.

Open-coded instances replaced with calling it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

new "syscall start" flag; handled in syscall_trace() by switching
syscall number to that of syscall_restart(2).  Restarts of that
kind (ERESTART_RESTARTBLOCK) are handled by setting that bit;
syscall number is not modified until the actual call.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

checking in do_signal() is pointless - if we get there with !user_mode(regs)
(and we might), we'll end up looping indefinitely.  Check in work_pending
and break out of the loop if so.
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

get_signal_to_deliver() will handle it itself
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This patch adds support for CMA to dma-mapping subsystem for ARM
architecture. By default a global CMA area is used, but specific devices
are allowed to have their private memory areas if required (they can be
created with dma_declare_contiguous() function during board
initialisation).

Contiguous memory areas reserved for DMA are remapped with 2-level page
tables on boot. Once a buffer is requested, a low memory kernel mapping
is updated to to match requested memory access type.

GFP_ATOMIC allocations are performed from special pool which is created
early during boot. This way remapping page attributes is not needed on
allocation time.

CMA has been enabled unconditionally for ARMv6+ systems.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Tested-by: NRob Clark <rob.clark@linaro.org>
Tested-by: NOhad Ben-Cohen <ohad@wizery.com>
Tested-by: NBenjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: NRobert Nelson <robertcnelson@gmail.com>
Tested-by: NBarry Song <Baohua.Song@csr.com>

No one uses the per-hw list of buses, so get rid of this.  Instead,
build the list locally.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

- Store uids and gids with kuid_t and kgid_t in struct kstat
- Convert uid and gids to userspace usable values with
  from_kuid and from_kgid
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>