Eric Lee / smarc-fsl-linux-kernel

12 Jan, 2007

1 commit

  • b282b6f8a   [PATCH] Change cpu_up and co from __devinit to __cpuinit ... Browse Code »

    Compiling the kernel with CONFIG_HOTPLUG = y and CONFIG_HOTPLUG_CPU = n
    with CONFIG_RELOCATABLE = y generates the following modpost warnings

    WARNING: vmlinux - Section mismatch: reference to .init.data: from
    .text between '_cpu_up' (at offset 0xc0141b7d) and 'cpu_up'
    WARNING: vmlinux - Section mismatch: reference to .init.data: from
    .text between '_cpu_up' (at offset 0xc0141b9c) and 'cpu_up'
    WARNING: vmlinux - Section mismatch: reference to .init.text:__cpu_up
    from .text between '_cpu_up' (at offset 0xc0141bd8) and 'cpu_up'
    WARNING: vmlinux - Section mismatch: reference to .init.data: from
    .text between '_cpu_up' (at offset 0xc0141c05) and 'cpu_up'
    WARNING: vmlinux - Section mismatch: reference to .init.data: from
    .text between '_cpu_up' (at offset 0xc0141c26) and 'cpu_up'
    WARNING: vmlinux - Section mismatch: reference to .init.data: from
    .text between '_cpu_up' (at offset 0xc0141c37) and 'cpu_up'

    This is because cpu_up, _cpu_up and __cpu_up (in some architectures) are
    defined as __devinit
    AND
    __cpu_up calls some __cpuinit functions.

    Since __cpuinit would map to __init with this kind of a configuration,
    we get a .text refering .init.data warning.

    This patch solves the problem by converting all of __cpu_up, _cpu_up
    and cpu_up from __devinit to __cpuinit. The approach is justified since
    the callers of cpu_up are either dependent on CONFIG_HOTPLUG_CPU or
    are of __init type.

    Thus when CONFIG_HOTPLUG_CPU=y, all these cpu up functions would land up
    in .text section, and when CONFIG_HOTPLUG_CPU=n, all these functions would
    land up in .init section.

    Tested on a i386 SMP machine running linux-2.6.20-rc3-mm1.

    Signed-off-by: Gautham R Shenoy
    Cc: Vivek Goyal
    Cc: Mikael Starvik
    Cc: Ralf Baechle
    Cc: Kyle McMartin
    Cc: Paul Mackerras
    Cc: Benjamin Herrenschmidt
    Cc: "David S. Miller"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Gautham R Shenoy
     

24 Dec, 2006

1 commit

  • e1d9fd2e3   [PATCH] suspend: fix suspend on single-CPU systems ... Browse Code »

    Clark Williams reported that suspend doesnt work on his laptop on
    2.6.20-rc1-rt kernels. The bug was introduced by the following cleanup
    commit:

    commit 112cecb2cc0e7341db92281ba04b26c41bb8146d
    Author: Siddha, Suresh B
    Date: Wed Dec 6 20:34:31 2006 -0800

    [PATCH] suspend: don't change cpus_allowed for task initiating the suspend

    because with this change 'error' is not initialized to 0 anymore, if
    there are no other online CPUs. (i.e. if the system is single-CPU).

    the fix is the initialize it to 0. The really weird thing is that my
    version of gcc does not warn about this non-initialized variable
    situation ...

    (also fix the kernel printk in the error branch, it was missing a
    newline)

    Reported-by: Clark Williams
    Signed-off-by: Ingo Molnar
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     

08 Dec, 2006

1 commit

06 Nov, 2006

1 commit

  • 4b96b1a10   [PATCH] Fix the spurious unlock_cpu_hotplug false warnings ... Browse Code »

    Cpu-hotplug locking has a minor race case caused because of setting the
    variable "recursive" to NULL *after* releasing the cpu_bitmask_lock in the
    function unlock_cpu_hotplug,instead of doing so before releasing the
    cpu_bitmask_lock.

    This was the cause of most of the recent false spurious lock_cpu_unlock
    warnings.

    This should fix the problem reported by Martin Lorenz reported in
    http://lkml.org/lkml/2006/10/29/127.

    Thanks to Srinivasa DS for pointing it out.

    Signed-off-by: Gautham R Shenoy
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Gautham R Shenoy
     

29 Oct, 2006

1 commit

17 Oct, 2006

1 commit

  • bd5349cfd   [PATCH] Convert cpu hotplug notifiers to use raw_notifier instead of blocking_notifier ... Browse Code »

    The use of blocking notifier by _cpu_up and _cpu_down in cpu.c has two
    problem.

    1/ An interaction with the workqueue notifier causes lockdep to spit a
    warning.

    2/ A notifier could conceivable be added or removed while _cpu_up or
    _cpu_down are in process. As each notifier is called twice (prepare
    then commit/abort) this could be unhealthy.

    To fix to we simply take cpu_add_remove_lock while adding or removing
    notifiers to/from the list.

    This makes the 'blocking' usage unnecessary as all accesses to cpu_chain
    are now protected by cpu_add_remove_lock. So change "blocking" to "raw" in
    all relevant places. This fixes 1.

    Credit: Andrew Morton
    Cc: Rusty Russell
    Cc: Michal Piotrowski (reporter)
    Signed-off-by: Neil Brown
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Neil Brown
     

26 Sep, 2006

1 commit

  • e3920fb42   [PATCH] Disable CPU hotplug during suspend ... Browse Code »

    The current suspend code has to be run on one CPU, so we use the CPU
    hotplug to take the non-boot CPUs offline on SMP machines. However, we
    should also make sure that these CPUs will not be enabled by someone else
    after we have disabled them.

    The functions disable_nonboot_cpus() and enable_nonboot_cpus() are moved to
    kernel/cpu.c, because they now refer to some stuff in there that should
    better be static. Also it's better if disable_nonboot_cpus() returns an
    error instead of panicking if something goes wrong, and
    enable_nonboot_cpus() has no reason to panic(), because the CPUs may have
    been enabled by the userland before it tries to take them online.

    Signed-off-by: Rafael J. Wysocki
    Acked-by: Pavel Machek
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Rafael J. Wysocki
     

24 Jul, 2006

1 commit

  • aa9538777   cpu hotplug: simplify and hopefully fix locking ... Browse Code »

    The CPU hotplug locking was quite messy, with a recursive lock to
    handle the fact that both the actual up/down sequence wanted to
    protect itself from being re-entered, but the callbacks that it
    called also tended to want to protect themselves from CPU events.

    This splits the lock into two (one to serialize the whole hotplug
    sequence, the other to protect against the CPU present bitmaps
    changing). The latter still allows recursive usage because some
    subsystems (ondemand policy for cpufreq at least) had already gotten
    too used to the lax locking, but the locking mistakes are hopefully
    now less fundamental, and we now warn about recursive lock usage
    when we see it, in the hope that it can be fixed.

    Signed-off-by: Linus Torvalds

    Linus Torvalds
     

28 Jun, 2006

1 commit

  • 65edc68c3   [PATCH] cpu hotplug: make [un]register_cpu_notifier init time only ... Browse Code »

    CPUs come online only at init time (unless CONFIG_HOTPLUG_CPU is defined).
    So, cpu_notifier functionality need to be available only at init time.

    This patch makes register_cpu_notifier() available only at init time, unless
    CONFIG_HOTPLUG_CPU is defined.

    This patch exports register_cpu_notifier() and unregister_cpu_notifier() only
    if CONFIG_HOTPLUG_CPU is defined.

    Signed-off-by: Chandra Seetharaman
    Cc: Ashok Raj
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Chandra Seetharaman
     

27 Jun, 2006

1 commit

  • 81615b624   [PATCH] Convert kernel/cpu.c to mutexes ... Browse Code »

    Convert kernel/cpu.c from semaphore to mutex.

    I've reviewed all lock_cpu_hotplug() critical sections, and they all seem to
    fit mutex semantics.

    Signed-off-by: Ingo Molnar
    Cc: Rusty Russell
    Cc: Ashok Raj
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     

28 Mar, 2006

1 commit

  • e041c6834   [PATCH] Notifier chain update: API changes ... Browse Code »

    The kernel's implementation of notifier chains is unsafe. There is no
    protection against entries being added to or removed from a chain while the
    chain is in use. The issues were discussed in this thread:

    http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2

    We noticed that notifier chains in the kernel fall into two basic usage
    classes:

    "Blocking" chains are always called from a process context
    and the callout routines are allowed to sleep;

    "Atomic" chains can be called from an atomic context and
    the callout routines are not allowed to sleep.

    We decided to codify this distinction and make it part of the API. Therefore
    this set of patches introduces three new, parallel APIs: one for blocking
    notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
    really just the old API under a new name). New kinds of data structures are
    used for the heads of the chains, and new routines are defined for
    registration, unregistration, and calling a chain. The three APIs are
    explained in include/linux/notifier.h and their implementation is in
    kernel/sys.c.

    With atomic and blocking chains, the implementation guarantees that the chain
    links will not be corrupted and that chain callers will not get messed up by
    entries being added or removed. For raw chains the implementation provides no
    guarantees at all; users of this API must provide their own protections. (The
    idea was that situations may come up where the assumptions of the atomic and
    blocking APIs are not appropriate, so it should be possible for users to
    handle these things in their own way.)

    There are some limitations, which should not be too hard to live with. For
    atomic/blocking chains, registration and unregistration must always be done in
    a process context since the chain is protected by a mutex/rwsem. Also, a
    callout routine for a non-raw chain must not try to register or unregister
    entries on its own chain. (This did happen in a couple of places and the code
    had to be changed to avoid it.)

    Since atomic chains may be called from within an NMI handler, they cannot use
    spinlocks for synchronization. Instead we use RCU. The overhead falls almost
    entirely in the unregister routine, which is okay since unregistration is much
    less frequent that calling a chain.

    Here is the list of chains that we adjusted and their classifications. None
    of them use the raw API, so for the moment it is only a placeholder.

    ATOMIC CHAINS
    -------------
    arch/i386/kernel/traps.c: i386die_chain
    arch/ia64/kernel/traps.c: ia64die_chain
    arch/powerpc/kernel/traps.c: powerpc_die_chain
    arch/sparc64/kernel/traps.c: sparc64die_chain
    arch/x86_64/kernel/traps.c: die_chain
    drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
    kernel/panic.c: panic_notifier_list
    kernel/profile.c: task_free_notifier
    net/bluetooth/hci_core.c: hci_notifier
    net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
    net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
    net/ipv6/addrconf.c: inet6addr_chain
    net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
    net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
    net/netlink/af_netlink.c: netlink_chain

    BLOCKING CHAINS
    ---------------
    arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
    arch/s390/kernel/process.c: idle_chain
    arch/x86_64/kernel/process.c idle_notifier
    drivers/base/memory.c: memory_chain
    drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
    drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
    drivers/macintosh/adb.c: adb_client_list
    drivers/macintosh/via-pmu.c sleep_notifier_list
    drivers/macintosh/via-pmu68k.c sleep_notifier_list
    drivers/macintosh/windfarm_core.c wf_client_list
    drivers/usb/core/notify.c usb_notifier_list
    drivers/video/fbmem.c fb_notifier_list
    kernel/cpu.c cpu_chain
    kernel/module.c module_notify_list
    kernel/profile.c munmap_notifier
    kernel/profile.c task_exit_notifier
    kernel/sys.c reboot_notifier_list
    net/core/dev.c netdev_chain
    net/decnet/dn_dev.c: dnaddr_chain
    net/ipv4/devinet.c: inetaddr_chain

    It's possible that some of these classifications are wrong. If they are,
    please let us know or submit a patch to fix them. Note that any chain that
    gets called very frequently should be atomic, because the rwsem read-locking
    used for blocking chains is very likely to incur cache misses on SMP systems.
    (However, if the chain's callout routines may sleep then the chain cannot be
    atomic.)

    The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
    material written by Keith Owens and suggestions from Paul McKenney and Andrew
    Morton.

    [jes@sgi.com: restructure the notifier chain initialization macros]
    Signed-off-by: Alan Stern
    Signed-off-by: Chandra Seetharaman
    Signed-off-by: Jes Sorensen
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Stern
     

25 Mar, 2006

1 commit

29 Nov, 2005

1 commit

  • a9d9baa1e   [PATCH] clean up lock_cpu_hotplug() in cpufreq ... Browse Code »

    There are some callers in cpufreq hotplug notify path that the lowest
    function calls lock_cpu_hotplug(). The lock is already held during
    cpu_up() and cpu_down() calls when the notify calls are broadcast to
    registered clients.

    Ideally if possible, we could disable_preempt() at the highest caller and
    make sure we dont sleep in the path down in cpufreq->driver_target() calls
    but the calls are so intertwined and cumbersome to cleanup.

    Hence we consistently use lock_cpu_hotplug() and unlock_cpu_hotplug() in
    all places.

    - Removed export of cpucontrol semaphore and made it static.
    - removed explicit uses of up/down with lock_cpu_hotplug()
    so we can keep track of the the callers in same thread context and
    just keep refcounts without calling a down() that causes a deadlock.
    - Removed current_in_hotplug() uses
    - Removed PF_HOTPLUG_CPU in sched.h introduced for the current_in_hotplug()
    temporary workaround.

    Tested with insmod of cpufreq_stat.ko, and logical online/offline
    to make sure we dont have any hang situations.

    Signed-off-by: Ashok Raj
    Cc: Zwane Mwaikambo
    Cc: Shaohua Li
    Cc: "Siddha, Suresh B"
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ashok Raj
     

09 Nov, 2005

1 commit

  • 90d45d17f   [PATCH] cpu hotplug: fix locking in cpufreq drivers ... Browse Code »

    When calling target drivers to set frequency, we take cpucontrol lock.
    When we modified the code to accomodate CPU hotplug, there was an attempt
    to take a double lock of cpucontrol leading to a deadlock. Since the
    current thread context is already holding the cpucontrol lock, we dont need
    to make another attempt to acquire it.

    Now we leave a trace in current->flags indicating current thread already is
    under cpucontrol lock held, so we dont attempt to do this another time.

    Thanks to Andrew Morton for the beating:-)

    From: Brice Goglin

    Build fix

    (akpm: this patch is still unpleasant. Ashok continues to look for a cleaner
    solution, doesn't he? ;))

    Signed-off-by: Ashok Raj
    Signed-off-by: Brice Goglin
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ashok Raj
     

31 Oct, 2005

1 commit

  • c32b6b8e5   [PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers ... Browse Code »

    cpufreq entries in sysfs should only be populated when CPU is online state.
    When we either boot with maxcpus=x and then boot the other cpus by echoing
    to sysfs online file, these entries should be created and destroyed when
    CPU_DEAD is notified. Same treatement as cache entries under sysfs.

    We place the processor in the lowest frequency, so hw managed P-State
    transitions can still work on the other threads to save power.

    Primary goal was to just make these directories appear/disapper dynamically.

    There is one in this patch i had to do, which i really dont like myself but
    probably best if someone handling the cpufreq infrastructure could give
    this code right treatment if this is not acceptable. I guess its probably
    good for the first cut.

    - Converting lock_cpu_hotplug()/unlock_cpu_hotplug() to disable/enable preempt.
    The locking was smack in the middle of the notification path, when the
    hotplug is already holding the lock. I tried another solution to avoid this
    so avoid taking locks if we know we are from notification path. The solution
    was getting very ugly and i decided this was probably good for this iteration
    until someone who understands cpufreq could do a better job than me.

    (akpm: export cpucontrol to GPL modules: drivers/cpufreq/cpufreq_stats.c now
    does lock_cpu_hotplug())

    Signed-off-by: Ashok Raj
    Signed-off-by: Venkatesh Pallipadi
    Cc: Dave Jones
    Cc: Zwane Mwaikambo
    Cc: Greg KH
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ashok Raj
     

26 Jun, 2005

1 commit

  • f37051364   [PATCH] i386 CPU hotplug ... Browse Code »

    (The i386 CPU hotplug patch provides infrastructure for some work which Pavel
    is doing as well as for ACPI S3 (suspend-to-RAM) work which Li Shaohua
    is doing)

    The following provides i386 architecture support for safely unregistering and
    registering processors during runtime, updated for the current -mm tree. In
    order to avoid dumping cpu hotplug code into kernel/irq/* i dropped the
    cpu_online check in do_IRQ() by modifying fixup_irqs(). The difference being
    that on cpu offline, fixup_irqs() is called before we clear the cpu from
    cpu_online_map and a long delay in order to ensure that we never have any
    queued external interrupts on the APICs. There are additional changes to s390
    and ppc64 to account for this change.

    1) Add CONFIG_HOTPLUG_CPU
    2) disable local APIC timer on dead cpus.
    3) Disable preempt around irq balancing to prevent CPUs going down.
    4) Print irq stats for all possible cpus.
    5) Debugging check for interrupts on offline cpus.
    6) Hacky fixup_irqs() to redirect irqs when cpus go off/online.
    7) play_dead() for offline cpus to spin inside.
    8) Handle offline cpus set in flush_tlb_others().
    9) Grab lock earlier in smp_call_function() to prevent CPUs going down.
    10) Implement __cpu_disable() and __cpu_die().
    11) Enable local interrupts in cpu_enable() after fixup_irqs()
    12) Don't fiddle with NMI on dead cpu, but leave intact on other cpus.
    13) Program IRQ affinity whilst cpu is still in cpu_online_map on offline.

    Signed-off-by: Zwane Mwaikambo
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Zwane Mwaikambo
     

17 Apr, 2005

1 commit

  • 1da177e4c   Linux-2.6.12-rc2 ... Browse Code »

    Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds