linux-toradex.git/arch/mips/kernel, branch v2.6.38.2

MIPS: Move idle task creation to work queue

2011-03-14T20:07:27+00:00

To avoid forking usermode thread when creating an idle task, move fork_idle
to a work queue.

If kernel starts with maxcpus= option which does not bring all available
cpus online at boot time, idle tasks for offline cpus are not created. If
later offline cpus are hotplugged through sysfs, __cpu_up is called in
the context of the user task, and fork_idle copies its non-zero mm
pointer.  This causes BUG() in per_cpu_trap_init.

This also avoids issues with resource limits of the CPU writing to sysfs,
containers, maybe others.

Signed-off-by: Maksim Rayskiy 
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2070/
Signed-off-by: Ralf Baechle

MIPS, Perf-events: Use unsigned delta for right shift in event update

2011-03-14T20:07:27+00:00

Leverage the commit for ARM by Will Deacon:

- 446a5a8b1eb91a6990e5c8fe29f14e7a95b69132
    ARM: 6205/1: perf: ensure counter delta is treated as unsigned

    Hardware performance counters on ARM are 32-bits wide but atomic64_t
    variables are used to represent counter data in the hw_perf_event structure.

    The armpmu_event_update function right-shifts a signed 64-bit delta variable
    and adds the result to the event count. This can lead to shifting in sign-bits
    if the MSB of the 32-bit counter value is set. This results in perf output
    such as:

     Performance counter stats for 'sleep 20':

     18446744073460670464  cycles             <-- 0xFFFFFFFFF12A6000
            7783773  instructions             #      0.000 IPC
                465  context-switches
                161  page-faults
            1172393  branches

       20.154242147  seconds time elapsed

    This patch ensures that the delta value is treated as unsigned so that the
    right shift sets the upper bits to zero.

Acked-by: Will Deacon 
Acked-by: David Daney 
Signed-off-by: Deng-Cheng Zhu 
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/2015/
Signed-off-by: Ralf Baechle

MIPS, Perf-events: Work with the new callchain interface

2011-03-14T20:07:27+00:00

This is the MIPS part of the following commits by Frederic Weisbecker:

- f72c1a931e311bb7780fee19e41a89ac42cab50e
    perf: Factorize callchain context handling

    Store the kernel and user contexts from the generic layer instead
    of archs, this gathers some repetitive code.

- 56962b4449af34070bb1994621ef4f0265eed4d8
    perf: Generalize some arch callchain code

    - Most archs use one callchain buffer per cpu, except x86 that needs
      to deal with NMIs. Provide a default perf_callchain_buffer()
      implementation that x86 overrides.

    - Centralize all the kernel/user regs handling and invoke new arch
      handlers from there: perf_callchain_user() / perf_callchain_kernel()
      That avoid all the user_mode(), current->mm checks and so...

    - Invert some parameters in perf_callchain_*() helpers: entry to the
      left, regs to the right, following the traditional (dst, src).

- 70791ce9ba68a5921c9905ef05d23f62a90bc10c
    perf: Generalize callchain_store()

    callchain_store() is the same on every archs, inline it in
    perf_event.h and rename it to perf_callchain_store() to avoid
    any collision.

    This removes repetitive code.

- c1a65932fd7216fdc9a0db8bbffe1d47842f862c
    perf: Drop unappropriate tests on arch callchains

    Drop the TASK_RUNNING test on user tasks for callchains as
    this check doesn't seem to make any sense.

    Also remove the tests for !current that is not supposed to
    happen and current->pid as this should be handled at the
    generic level, with exclude_idle attribute.

Reported-by: Wu Zhangjin 
Acked-by: Frederic Weisbecker 
Acked-by: David Daney 
Signed-off-by: Deng-Cheng Zhu 
To: a.p.zijlstra@chello.nl
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/2014/
Signed-off-by: Ralf Baechle

MIPS, Perf-events: Fix event check in validate_event()

2011-03-14T20:07:27+00:00

Ignore events that are in off/error state or belong to a different PMU.

This patch originates from the following commit for ARM by Will Deacon:

- 65b4711ff513767341aa1915c822de6ec0de65cb
    ARM: 6352/1: perf: fix event validation

    The validate_event function in the ARM perf events backend has the
    following problems:

    1.) Events that are disabled count towards the cost.
    2.) Events associated with other PMUs [for example, software events or
        breakpoints] do not count towards the cost, but do fail validation,
        causing the group to fail.

    This patch changes validate_event so that it ignores events in the
    PERF_EVENT_STATE_OFF state or that are scheduled for other PMUs.

Acked-by: Will Deacon 
Acked-by: David Daney 
Signed-off-by: Deng-Cheng Zhu 
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2013/
Signed-off-by: Ralf Baechle

MIPS, Perf-events: Work with the new PMU interface

2011-03-14T20:07:26+00:00

This is the MIPS part of the following commits by Peter Zijlstra:

- a4eaf7f14675cb512d69f0c928055e73d0c6d252
    perf: Rework the PMU methods

    Replace pmu::{enable,disable,start,stop,unthrottle} with
    pmu::{add,del,start,stop}, all of which take a flags argument.

    The new interface extends the capability to stop a counter while
    keeping it scheduled on the PMU. We replace the throttled state with
    the generic stopped state.

    This also allows us to efficiently stop/start counters over certain
    code paths (like IRQ handlers).

    It also allows scheduling a counter without it starting, allowing for
    a generic frozen state (useful for rotating stopped counters).

    The stopped state is implemented in two different ways, depending on
    how the architecture implemented the throttled state:

     1) We disable the counter:
        a) the pmu has per-counter enable bits, we flip that
        b) we program a NOP event, preserving the counter state

     2) We store the counter state and ignore all read/overflow events

For MIPSXX, the stopped state is implemented in the way of 1.b as above.

- 33696fc0d141bbbcb12f75b69608ea83282e3117
    perf: Per PMU disable

    Changes perf_disable() into perf_pmu_disable().

- 24cd7f54a0d47e1d5b3de29e2456bfbd2d8447b7
    perf: Reduce perf_disable() usage

    Since the current perf_disable() usage is only an optimization,
    remove it for now. This eases the removal of the __weak
    hw_perf_enable() interface.

- b0a873ebbf87bf38bf70b5e39a7cadc96099fa13
    perf: Register PMU implementations

    Simple registration interface for struct pmu, this provides the
    infrastructure for removing all the weak functions.

- 51b0fe39549a04858001922919ab355dee9bdfcf
    perf: Deconstify struct pmu

    sed -ie 's/const struct pmu\>/struct pmu/g' `git grep -l "const struct pmu\>"`

Reported-by: Wu Zhangjin 
Acked-by: David Daney 
Signed-off-by: Deng-Cheng Zhu 
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2012/
Signed-off-by: Ralf Baechle

MIPS, Perf-events: Work with irq_work

2011-03-14T20:07:26+00:00

This is the MIPS part of the following commit by Peter Zijlstra:

- e360adbe29241a0194e10e20595360dd7b98a2b3
    irq_work: Add generic hardirq context callbacks

    Provide a mechanism that allows running code in IRQ context. It is
    most useful for NMI code that needs to interact with the rest of the
    system -- like wakeup a task to drain buffers.

    Perf currently has such a mechanism, so extract that and provide it as
    a generic feature, independent of perf so that others may also
    benefit.

    The IRQ context callback is generated through self-IPIs where
    possible, or on architectures like powerpc the decrementer (the
    built-in timer facility) is set to generate an interrupt immediately.

    Architectures that don't have anything like this get to do with a
    callback from the timer tick. These architectures can call
    irq_work_run() at the tail of any IRQ handlers that might enqueue such
    work (like the perf IRQ handler) to avoid undue latencies in
    processing the work.

For MIPSXX, we need to call irq_work_run() at the tail of the perf IRQ
handler as described above.

Reported-by: Wu Zhangjin 
Acked-by: Peter Zijlstra 
Acked-by: David Daney 
Signed-off-by: Deng-Cheng Zhu 
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com,
Patchwork: http://patchwork.linux-mips.org/patch/2011/
Signed-off-by: Ralf Baechle

MIPS: Remove unused code from arch/mips/kernel/syscall.c

2011-03-14T20:07:26+00:00

The variable arg3 in _sys_sysmips() is unused.  Remove it.

Signed-off-by: David Daney 
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2034/
Signed-off-by: Ralf Baechle

MIPS: Fix GCC-4.6 'set but not used' warning in signal*.c

2011-03-14T20:07:25+00:00

GCC-4.6 can find more unused code than previous versions could.

In the case of protected_restore_fp_context{,32}, the variable tmp is
really used.  Its use is tricky in that we really care about the side
effects of the __put_user() calls.  So we must mark tmp with
__maybe_unused to quiet the warning.

Signed-off-by: David Daney 
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2035/
Signed-off-by: Ralf Baechle

MIPS: Clear the correct flag in sysmips(MIPS_FIXADE, ...).

2011-03-14T20:07:25+00:00

The sysmips(MIPS_FIXADE, ...) case contains an obvious copy-and-paste
error in the handling of the TIF_LOGADE flag. Fix that

Patchwork: https://patchwork.linux-mips.org/patch/1997/
Signed-off-by: Ralf Baechle

MIPS, Tracing: Fix set_graph_function of function graph tracer

2011-03-14T20:07:24+00:00

trace.func should be set to the recorded ip of the mcount calling site
in the __mcount_loc section to filter the function entries configured
through the tracing/set_graph_function interface, but before, this is
set to the self_ra(the return address of mcount), which has made
set_graph_function not work as expected.

This fixes it via calculating the right recorded ip in the __mcount_loc
section and assign it to trace.func.

Reported-by: Zhiping Zhong 
Signed-off-by: Wu Zhangjin 
Cc: Steven Rostedt 
Cc: Sergei Shtylyov 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2017/
Signed-off-by: Ralf Baechle