Commit Graph

1678 Commits

Author SHA1 Message Date
Thomas Gleixner
b10bbbbce7 Blackfin: use proper wrappers for irq_desc
Fixup the open coded access to irq_desc and use the proper wrappers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:05 -04:00
Mike Frysinger
511cdcc500 Blackfin: optimize startup code
Take advantage of more Blackfin-specific insns, and only initialize
registers required by the ABI.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:04 -04:00
Sonic Zhang
c6345ab1a3 Blackfin: SMP: work around anomaly 05000491
In order to safely work around anomaly 05000491, we have to execute IFLUSH
from L1 instruction sram.  The trouble with multi-core systems is that all
L1 sram is visible only to the active core.  So we can't just place the
functions into L1 and call it directly.  We need to setup a jump table and
place the entry point in external memory.  This will call the right func
based on the active core.

In the process, convert from the manual relocation of a small bit of code
into Core B's L1 to the more general framework we already have in place
for loading arbitrary pieces of code into L1.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:04 -04:00
Graf Yang
6f546bc3ac Blackfin: SMP: implement cpu_freq support
Re-use some of the existing cpu hotplugging code in the process.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:03 -04:00
Mike Frysinger
820b127dae Blackfin: split optimization settings more
We need to place icache flush funcs into L1 inst sram to work around a
hardware anomaly.  But this currently breaks SMP support as the L1 inst
sram is per-core and cannot be called directly.  So in preparation for
making that work, split the two options.

Further, split out the SMP depend so that we can allow some for SMP.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:03 -04:00
Sonic Zhang
567ebfc99d Blackfin: SMP: disable preempt with smp_processor_id to send messages
The smp_processor_id() API requires that preempt be disabled when calling
it, so make sure it is when we go to send messages to other processors.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:02 -04:00
steven miao
ab61d2ac5c Blackfin: SMP: delay enabling caches until CPU is initialized
Defer bfin_setup_caches(cpu) to avoid unexpected faults due to the cpu
state not yet being fully initialized.

Signed-off-by: steven miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:02 -04:00
Mike Frysinger
5f362c91d0 Blackfin: SMP: use standard cache functions
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:01 -04:00
steven miao
ef9d8c251a Blackfin: SMP: PERCPU section should be PAGE aligned
Common code checks the alignment of some of the variables and calls BUG()
if they aren't page aligned.

Signed-off-by: steven miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 04:01:01 -04:00
Mike Frysinger
d6b435be4b Blackfin: ADI boards: enable pseudo debug insns support
We use these insns when testing, so enable them by default for all
of our development boards.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:26 -04:00
Sonic Zhang
cdb92f6794 Blackfin: kgdb: drop dead KGDB_THR_PROC_SWAP for SMP systems
Common code no longer defines this, so stop using it.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:26 -04:00
Andreas Schallenberg
adfe6a4882 Blackfin: dnp5370: drop MMC card detect support
The board doesn't actually have a pin hooked up to do card detection,
so punt the code for it.

Signed-off-by: Andreas Schallenberg <Andreas.Schallenberg@3alitydigital.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:25 -04:00
Mike Frysinger
b5fc12df90 Blackfin: add bfin_write_{or,and} helpers
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:24 -04:00
Aaron Wu
4c131c8c23 Blackfin: bf548-ezkit: add CAN1 support
Signed-off-by: Aaron Wu <aaronwu06@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:24 -04:00
steven miao
55835175a0 Blackfin: bf54x: add kconfig for UART2/3 DMA channel assignments
The BF54x lacks dedicated DMA channels for the UART peripherals and need
to be muxed between others.  So add a kconfig option so people can select
which channels the UARTs will use so they can pick between SPORTs and the
less commonly used EPPI/PIXC peripherals.

Signed-off-by: steven miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:23 -04:00
Sonic Zhang
6ce0466d63 Blackfin: SMP: avoid section mismatch warnings
Since coreb_trampoline_start() calls coreb_start(), they need to be in
the same section.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-18 03:49:22 -04:00
Linus Torvalds
79d8a8f736 Merge branch 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu, x86: Add arch-specific this_cpu_cmpxchg_double() support
  percpu: Generic support for this_cpu_cmpxchg_double()
  alpha: use L1_CACHE_BYTES for cacheline size in the linker script
  percpu: align percpu readmostly subsection to cacheline

Fix up trivial conflict in arch/x86/kernel/vmlinux.lds.S due to the
percpu alignment having changed ("x86: Reduce back the alignment of the
per-CPU data section")
2011-03-16 08:22:41 -07:00
Linus Torvalds
420c1c572d Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (62 commits)
  posix-clocks: Check write permissions in posix syscalls
  hrtimer: Remove empty hrtimer_init_hres_timer()
  hrtimer: Update hrtimer->state documentation
  hrtimer: Update base[CLOCK_BOOTTIME].offset correctly
  timers: Export CLOCK_BOOTTIME via the posix timers interface
  timers: Add CLOCK_BOOTTIME hrtimer base
  time: Extend get_xtime_and_monotonic_offset() to also return sleep
  time: Introduce get_monotonic_boottime and ktime_get_boottime
  hrtimers: extend hrtimer base code to handle more then 2 clockids
  ntp: Remove redundant and incorrect parameter check
  mn10300: Switch do_timer() to xtimer_update()
  posix clocks: Introduce dynamic clocks
  posix-timers: Cleanup namespace
  posix-timers: Add support for fd based clocks
  x86: Add clock_adjtime for x86
  posix-timers: Introduce a syscall for clock tuning.
  time: Splitout compat timex accessors
  ntp: Add ADJ_SETOFFSET mode bit
  time: Introduce timekeeping_inject_offset
  posix-timer: Update comment
  ...

Fix up new system-call-related conflicts in
	arch/x86/ia32/ia32entry.S
	arch/x86/include/asm/unistd_32.h
	arch/x86/include/asm/unistd_64.h
	arch/x86/kernel/syscall_table_32.S
(name_to_handle_at()/open_by_handle_at() vs clock_adjtime()), and some
due to movement of get_jiffies_64() in:
	kernel/time.c
2011-03-15 18:53:35 -07:00
Mike Frysinger
be1229b4c5 Blackfin: iflush: update anomaly 05000491 workaround
Recent feedback from design says we need three NOPs in the hardware loop.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-04 01:27:01 -05:00
Mike Frysinger
bb7b11290a Blackfin: outs[lwb]: make sure count is greater than 0
Some devices will use the outs* funcs with a length of zero, so make sure
we do not write any data in that case.

Reported-by: Gilbert Inho <gneny@edevice.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-03-04 01:26:55 -05:00
Sonic Zhang
0f66e50af5 serial: bfin_5xx: split uart RX lock from uart port lock to avoid deadlock
The RX lock is used to protect the RX buffer from concurrent access in DMA
mode between the timer and RX interrupt routines.  It is independent from
the uart lock which is used to protect the TX buffer.  It is possible for
a uart TX transfer to be started up from the RX interrupt handler if low
latency is enabled.  So we need to split the locks to avoid deadlocking in
this situation.

In PIO mode, the RX lock is not necessary because the handle_simple_irq
and handle_level_irq functions ensure driver interrupt handlers are called
once on one core.

And now that the RX path has its own lock, the TX interrupt has nothing to
do with the RX path, so disabling it at the same time.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-03 14:44:54 -08:00
Torben Hohn
4196b892d5 blackfin: Switch from do_timer() to xtime_update()
xtime_update() takes the xtime_lock itself.

Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: johnstul@us.ibm.com
Cc: hch@infradead.org
Cc: yong.zhang0@gmail.com
LKML-Reference: <20110127145931.23248.33917.stgit@localhost>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-31 14:55:44 +01:00
Tejun Heo
19df0c2fef percpu: align percpu readmostly subsection to cacheline
Currently percpu readmostly subsection may share cachelines with other
percpu subsections which may result in unnecessary cacheline bounce
and performance degradation.

This patch adds @cacheline parameter to PERCPU() and PERCPU_VADDR()
linker macros, makes each arch linker scripts specify its cacheline
size and use it to align percpu subsections.

This is based on Shaohua's x86 only patch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Shaohua Li <shaohua.li@intel.com>
2011-01-25 14:26:50 +01:00
Thomas Gleixner
7b02886349 blackfin: Use generic irq Kconfig
No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Frysinger <vapier@gentoo.org>
2011-01-21 11:55:31 +01:00
Thomas Gleixner
1c77ff22f5 genirq: Remove __do_IRQ
All architectures are finally converted. Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Michal Simek <monstr@monstr.eu>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jeff Dike <jdike@addtoit.com>
2011-01-21 11:55:31 +01:00
David Rientjes
6a108a14fa kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option
is used to configure any non-standard kernel with a much larger scope than
only small devices.

This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes
references to the option throughout the kernel.  A new CONFIG_EMBEDDED
option is added that automatically selects CONFIG_EXPERT when enabled and
can be used in the future to isolate options that should only be
considered for embedded systems (RISC architectures, SLOB, etc).

Calling the option "EXPERT" more accurately represents its intention: only
expert users who understand the impact of the configuration changes they
are making should enable it.

Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: David Woodhouse <david.woodhouse@intel.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Greg KH <gregkh@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robin Holt <holt@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-20 17:02:05 -08:00
Linus Torvalds
008d23e485 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits)
  Documentation/trace/events.txt: Remove obsolete sched_signal_send.
  writeback: fix global_dirty_limits comment runtime -> real-time
  ppc: fix comment typo singal -> signal
  drivers: fix comment typo diable -> disable.
  m68k: fix comment typo diable -> disable.
  wireless: comment typo fix diable -> disable.
  media: comment typo fix diable -> disable.
  remove doc for obsolete dynamic-printk kernel-parameter
  remove extraneous 'is' from Documentation/iostats.txt
  Fix spelling milisec -> ms in snd_ps3 module parameter description
  Fix spelling mistakes in comments
  Revert conflicting V4L changes
  i7core_edac: fix typos in comments
  mm/rmap.c: fix comment
  sound, ca0106: Fix assignment to 'channel'.
  hrtimer: fix a typo in comment
  init/Kconfig: fix typo
  anon_inodes: fix wrong function name in comment
  fix comment typos concerning "consistent"
  poll: fix a typo in comment
  ...

Fix up trivial conflicts in:
 - drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c)
 - fs/ext4/ext4.h

Also fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.
2011-01-13 10:05:56 -08:00
Mike Frysinger
a780c6e868 Blackfin: encode cpu-rev into uImage name
Encoding the cpu family name apparently confuses people when they try to
boot an image on a sub-variant, so encode the specific cpu name and the
silicon rev instead.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:27 -05:00
Mike Frysinger
b66acb63f5 Blackfin: bf54x: don't ack GPIO ints when unmasking them
When unmasking a GPIO interrupt on a BF54x part, the code will implicitly
ack any pending interrupts.  This is not what unmasking should do and can
cause people to miss interrupts from their devices, so punt the code.

Reported-by: Rutger Hofman <rutger@cs.vu.nl>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:26 -05:00
Mike Frysinger
25f3ff2c44 Blackfin: sram_free_with_lsl: do not ignore return value of sram_free
If there was an error in the lower free functions, we need to pass that
back up so the calling process is able to check things.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:26 -05:00
Mike Frysinger
a8b1988609 Blackfin: boards: add missing "static" to peripheral lists
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:25 -05:00
Andreas Schallenberg
3ea9f2bf5a Blackfin: DNP5370: new board port
Signed-off-by: Andreas Schallenberg <Andreas.Schallenberg@3alitydigital.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:25 -05:00
Sonic Zhang
d57bc0feaa Blackfin: bf518f-ezbrd: fix dsa resources
On bf518-ezbrd with DSA Ethernet switch enabled, on chip MAC is
connecting to phy at address 3.  If allowing the netdevice framework to
probe both 3 phys of the switch when registering MAC phy, phy at address
1 is checked for link active status other than phy at address 3.  If
connecting a cable to port 2 and leave port 1 open, link status in phy
2 and 3 are online, while that in phy 1 is offline.  So, the phy layer
sets wrong offline status to net device on port 3.  In this case, no data
can be transferred via ethernet port 2.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:24 -05:00
Mike Frysinger
874f6cfd3a Blackfin: move "-m elf32bfin" to general LDFLAGS
Common code now invokes the linker directly which causes build failures
when using an FDPIC toolchain.  So move the emulation setting out of the
module-specific LDFLAGS and into the common LDFLAGS.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:24 -05:00
Vivi Li
9fc205283f Blackfin: kgdb_test: make sure to initialize num2
We check its value at runtime, so we want to avoid garbage across runs.

Signed-off-by: Vivi Li <vivi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:23 -05:00
Sonic Zhang
b68233e7f0 Blackfin: kgdb: disable preempt schedule when running single step in kgdb
Otherwise, gdb continue operation after a breakpoint is hit may trap
into endless breakpoint.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:23 -05:00
Sonic Zhang
900de05182 Blackfin: kgdb: disable interrupt when single stepping in ADEOS
When ADEOS and kgdb are both enabled, single step in linux kernel may be
scheduled to Xenomai core after return from interrupt handlers.  This
blocks gdb continue operation after a break point is hit.  So, disable
interrupt when running gdb single step.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:22 -05:00
Sonic Zhang
84e97c1014 Blackfin: SMP: kgdb: apply anomaly 257 work around
When run kgdb testing, it looks like coreb hangs in single step or trap
exception without handling anomaly 05000257 properly on bf561 v0.5.  But,
the anomaly list says it apply to bf561 v0.4 and bellow.  Apply its work
around to 0.5 temporarily until the behavior and the root cause can be
confirmed by the hardware team.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:22 -05:00
Mike Frysinger
503f3d30c6 Blackfin: fix building IPIPE code when XIP is enabled
The low level assembly needs to use the pseudo_long_call helper so that
we use the right call insn when doing kernel XIP.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:21 -05:00
Sonic Zhang
064cc44e62 Blackfin: SMP: kgdb: flush core internal write buffer before flushinv
KGDB single step in SMP kernel may hang forever in flushinv without a
CSYNC ahead.  This is because the core internal write buffers need to
be flushed before invalidating the data cache to make sure the insn
fetch is not out of sync.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:21 -05:00
Sonic Zhang
e54b673081 Blackfin: sport_uart resources: remove unused secondary RX/TX pins
The SPORT/UART driver doesn't use the secondary channel pins, so don't
try and request them thus keeping other drivers from using them.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:20 -05:00
Stefan Weil
e01b5b1296 Blackfin: tll6527m: fix spelling in unused code (struct name)
platfrom -> platform

This changes a struct name. The related code is conditionally
compiled and won't work because the include file linux/gpio-decoder.h
is missing, so removing this code would be an even better solution.

If the missing include file is added, it must fix the spelling, too.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:20 -05:00
Sonic Zhang
624fab3bcd Blackfin: bf527-ezkit: add adau1373 chip address
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:19 -05:00
Sonic Zhang
398834330c Blackfin: no-mpu: fix masking of small uncached dma region
When using an uncached DMA region less than 1 MiB, we try to mask off
the whole last 1 MiB for it.  Unfortunately, this fails as we forgot
to subtract one from the calculated mask, leading to the region still
be marked as cacheable.

Reported-by: Andrew Rook <andrew.rook@speakerbus.co.uk>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:18 -05:00
Steven Miao
36e11ab23e Blackfin: pm: drop irq save/restore in standby and suspend to mem callback
Since linux-2.6.31, the kernel suspend framework will do disable_irq/enable_irq,
so save/restore irq in standby and suspend to mem callback should be dropped.
Otherwise the common code notices things are enabled and complains.

Signed-off-by: Steven Miao <realmz6@gmail.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:18 -05:00
Mike Frysinger
e15124c14c Blackfin: dpmc.h: pull in new pll.h
Any consumer of dpmc.h expects to use VR_CTL, so also pull in the new
mach/pll.h header for those functions.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:17 -05:00
Mike Frysinger
77c90e3d35 Blackfin: bf54x: add MMR layout for PINT
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:17 -05:00
Mike Frysinger
ec5109e7ca Blackfin: bf561: SMP: add multicore pll handlers
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:16 -05:00
Mike Frysinger
10cdc1a78a Blackfin: unify pll.h headers
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:16 -05:00
Yi Li
73a400646b Blackfin: SMP: rewrite IPI handling to avoid memory allocation
Currently, sending an interprocessor interrupt (IPI) requires building up
a message dynamically which means memory allocation.  But often times, we
will want to send an IPI in low level contexts where allocation is not
possible which may lead to a panic().  So create a per-cpu static array
for the message queue and use that instead.

Further, while we have two supplemental interrupts, we are currently only
using one of them.  So use the second one for the most common IPI message
of all -- smp_send_reschedule().  This avoids ugly contention for locks
which in turn would require an IPI message ...

In general, this improves SMP performance, and in some cases allows the
SMP port to work in places it wouldn't before.  Such as the PREEMPT_RT
state where the slab is protected by a per-cpu spin lock.  If the slab
kmalloc/kfree were to put the task to sleep, and that task was actually
the IPI handler, then the system falls down yet again.

After running some various stress tests on the system, the static limit
of 5 messages seems to work.  On the off chance even this overflows, we
simply panic(), and we can review that scenario to see if the limit needs
to be increased a bit more.

Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2011-01-10 07:18:15 -05:00