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This patch add the handlers of SPE/EFP exceptions.
The code is used to emulate float point arithmetic,
when MSR(SPE) is enabled and receive EFP data interrupt or EFP round interrupt.
This patch has no conflict with or dependence on FP math-emu.
The code has been tested by TestFloat.
Now the code doesn't support SPE/EFP instructions emulation
(it won't be called when receive program interrupt),
but it could be easily added.
Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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This patch also includes the required removal of (unused) inclusion of
<asm/a.out.h> <linux/a.out.h>'s in the arch/ code for these
architectures.
[dwmw2: updated for 2.6.27-rc]
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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This patch implements support for HW based watchpoint via the
DBSR_DAC (Data Address Compare) facility of the BookE processors.
It does so by interfacing with the existing DABR breakpoint code
and adding the necessary bits and pieces for the new bits to
be properly set or cleared
Signed-off-by: Luis Machado <luisgpm@br.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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This patch extends the floating point save and restore code to use the
VSX load/stores when VSX is available. This will make FP context
save/restore marginally slower on FP only code, when VSX is available,
as it has to load/store 128bits rather than just 64bits.
Mixing FP, VMX and VSX code will get constant architected state.
The signals interface is extended to enable access to VSR 0-31
doubleword 1 after discussions with tool chain maintainers. Backward
compatibility is maintained.
The ptrace interface is also extended to allow access to VSR 0-31 full
registers.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch is based on work done by Madhvesh. R. Sulibhavi back in
March 2007.
We refactor some of the single step handling since it differs between
"classic" and "booke" powerpc cores.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Looks like "[POWERPC] kdump shutdown hook support" broke builds when
CONFIG_DEBUGGER=n and CONFIG_KEXEC=y, such as in g5_defconfig:
arch/powerpc/kernel/crash.c: In function 'default_machine_crash_shutdown':
arch/powerpc/kernel/crash.c:388: error: '__debugger_fault_handler' undeclared (first use in this function)
arch/powerpc/kernel/crash.c:388: error: (Each undeclared identifier is reported only once
arch/powerpc/kernel/crash.c:388: error: for each function it appears in.)
Move the debugger hooks to under CONFIG_DEBUGGER || CONFIG_KEXEC, since
that's when the crash code is enabled.
(I should have caught this with my build-script pre-merge, my bad. :( )
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This adds a cputable function pointer for the CPU-side machine
check handling. The semantic is still the same as the old one,
the one in ppc_md. overrides the one in cputable, though
ultimately we'll want to change that so the CPU gets first.
This removes CONFIG_440A which was a problem for multiplatform
kernels and instead fixes up the IVOR at runtime from a setup_cpu
function. The "A" version of the machine check also tweaks the
regs->trap value to differenciate the 2 versions at the C level.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
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isel (Integer Select) is a new user space instruction in the
PowerISA 2.04 spec. Not all processors implement it so lets emulate
to ensure code built with isel will run everywhere.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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One of the easiest things to isolate is the pid printed in kernel log.
There was a patch, that made this for arch-independent code, this one makes
so for arch/xxx files.
It took some time to cross-compile it, but hopefully these are all the
printks in arch code.
Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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is_init() is an ambiguous name for the pid==1 check. Split it into
is_global_init() and is_container_init().
A cgroup init has it's tsk->pid == 1.
A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns. But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.
Changelog:
2.6.22-rc4-mm2-pidns1:
- Use 'init_pid_ns.child_reaper' to determine if a given task is the
global init (/sbin/init) process. This would improve performance
and remove dependence on the task_pid().
2.6.21-mm2-pidns2:
- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
ppc,avr32}/traps.c for the _exception() call to is_global_init().
This way, we kill only the cgroup if the cgroup's init has a
bug rather than force a kernel panic.
[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: Pavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Implement show_unhandled_signals sysctl + support to print when a process
is killed due to unhandled signals just as i386 and x86_64 does.
Default to having it off, unlike x86 that defaults on.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Previously, Soft_emulate_8xx was called with no implementation, resulting in
build failures whenever building 8xx without math emulation. The
implementation is copied from arch/ppc to resolve this issue.
However, this sort of minimal emulation is not a very good idea other than
for compatibility with existing userspaces, as it's less efficient than
soft-float and can mislead users into believing they have soft-float. Thus,
it is made a configurable option, off by default.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Move out the old-style exception parsers to a separate function, and
don't call it on platforms that have a platform-specific handler.
It would make sense to move out the generic versions into their platforms
instead, but that can be done gradually down the road.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Remove leftover cruft from ARCH=ppc.
There are no users of platform_machine_check() in ARCH=powerpc, and none
should be added (they should use ppc_md.machine_check_handler instead).
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Reserved MCSR bits on FSL BookE parts may have spurious values
when mcheck occurs. Mask these off when printing the MCSR to
avoid confusion. Also, get rid of the MCSR_GL_CI bit defined
for e500 - this bit doesn't actually have any meaning.
Signed-off-by: Becky Bruce <becky.bruce@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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If the kernel OOPSed or BUGed then it probably should be considered as
tainted. Thus, all subsequent OOPSes and SysRq dumps will report the
tainted kernel. This saves a lot of time explaining oddities in the
calltraces.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Added parisc patch from Matthew Wilson -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The current generic bug implementation has a call to dump_stack() in case a
WARN_ON(whatever) gets hit. Since report_bug(), which calls dump_stack(),
gets called from an exception handler we can do better: just pass the
pt_regs structure to report_bug() and pass it to show_regs() in case of a
warning. This will give more debug informations like register contents,
etc... In addition this avoids some pointless lines that dump_stack()
emits, since it includes a stack backtrace of the exception handler which
is of no interest in case of a warning. E.g. on s390 the following lines
are currently always present in a stack backtrace if dump_stack() gets
called from report_bug():
[<000000000001517a>] show_trace+0x92/0xe8)
[<0000000000015270>] show_stack+0xa0/0xd0
[<00000000000152ce>] dump_stack+0x2e/0x3c
[<0000000000195450>] report_bug+0x98/0xf8
[<0000000000016cc8>] illegal_op+0x1fc/0x21c
[<00000000000227d6>] sysc_return+0x0/0x10
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch moves the die notifier handling to common code. Previous
various architectures had exactly the same code for it. Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)
arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at. avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-arch@vger.kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Looks like someone got this backwards, highlighting the perils of the
? : !!! :)
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Handle recursive oopses, like on x86. We had a few cases recently where
we locked up in oops printing and didnt make it into crashdump.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Move pmac_backlight_unblank into its own function and only take the
pmac_backlight_mutex when we are on a pmac for that added bit of
paranoia.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Add missing oops_enter/oops_exit, makes pause_on_oops boot parameter work.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Per device data such as brightness belongs to the indivdual device
and should therefore be separate from the the backlight operation
function pointers. This patch splits the two types of data and
allows simplifcation of some code.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
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backlight_device->sem has a very specific use as documented in the
header file. The external users of this are using it for a different
reason, to serialise access to the update_status() method.
backlight users were supposed to implement their own internal
serialisation of update_status() if needed but everyone is doing
things differently and incorrectly. Therefore add a global mutex to
take care of serialisation for everyone, once and for all.
Locking for get_brightness remains optional since most users don't
need it.
Also update the lcd class in a similar way.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
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When we do full FP emulation its possible that we need to post a SIGFPE based
on the results of the emulation. The previous code ignored this case completely.
Additionally, the Soft_emulate_8xx case had two issues. One, we should never
generate a SIGFPE since the code only does data movement. Second, we were
interpreting the return codes incorrectly, it returns 0 on success, 1 on
illop and -EFAULT on a data access error.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Anytime we are emulating an instruction we are going to be doing some form of
get_user() to get the instruction image to decode. Since get_user() might
sleep we need to ensure we have interrupts enabled or we might see something
like:
Debug: sleeping function called from invalid context at arch/powerpc/kernel/traps.c:697
in_atomic():0, irqs_disabled():1
Call Trace:
[D6023EB0] [C0007F84] show_stack+0x58/0x174 (unreliable)
[D6023EE0] [C0022C34] __might_sleep+0xbc/0xd0
[D6023EF0] [C000D158] program_check_exception+0x1d8/0x4fc
[D6023F40] [C000E744] ret_from_except_full+0x0/0x4c
--- Exception: 700 at 0x102a7100
LR = 0xdb9ef04
However, we want to ensure that interrupts are disabled when handling a trap
exception that might be used for a kernel breakpoint. This is why ProgramCheck
is marked as EXC_XFER_STD instead of EXC_XFER_EE.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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Use is_init() rather than hard coded pid comparison.
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This makes powerpc use the generic BUG machinery. The biggest reports the
function name, since it is redundant with kallsyms, and not needed in general.
There is an overall reduction of code, since module_32/64 duplicated several
functions.
Unfortunately there's no way to tell gcc that BUG won't return, so the BUG
macro includes a goto loop. This will generate a real jmp instruction, which
is never used.
[akpm@osdl.org: build fix]
[paulus@samba.org: remove infinite loop in BUG_ON]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The e300c2 has no FPU. Its MSR[FP] is grounded to zero. If an attempt
is made to execute a floating point instruction (including floating-point
load, store, or move instructions), the e300c2 takes a floating-point
unavailable interrupt.
This patch adds support for FP emulation on the e300c2 by declaring a
new CPU_FTR_FP_TAKES_FPUNAVAIL, where FP unavail interrupts are
intercepted and redirected to the ProgramCheck exception path for
correct emulation handling.
(If we run out of CPU_FTR bits we could look to reclaim this bit by adding
support to test the cpu_user_features for PPC_FEATURE_HAS_FPU instead)
It adds a nop to the exception path for 32-bit processors with a FPU.
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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powerpc: Merge 32 and 64 bits asm-powerpc/io.h
The rework on io.h done for the new hookable accessors made it easier,
so I just finished the work and merged 32 and 64 bits io.h for arch/powerpc.
arch/ppc still uses the old version in asm-ppc, there is just too much gunk
in there that I really can't be bothered trying to cleanup.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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The alignment exception used to only check the exception table for
-EFAULT, not for other errors. That opens an oops window if we can
coerce the kernel into getting an alignment exception for other reasons
in what would normally be a user-protected accessor, which can be done
via some of the futex ops. This fixes it by always checking the
exception tables.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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At the moment we rely on a cpu feature bit or a firmware property to
detect altivec. If we dont have either of these and the cpu does in fact
support altivec we can cause a panic from userspace.
It seems safer to always send a signal if we manage to get an 0xf20
exception from userspace.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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In an attempt to make it easier for a power5 optimized app to run on a
power4 or a 970 or random earlier machine, this provides emulation of
the popcntb instruction.
Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
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When we get an illegal instruction exception, we check to see whether
the instruction is one that we emulate for the user program. Some of
the masks we use in checking whether the offending instruction is one
we care about didn't have the top bit set, which is the MSB of the
major opcode. Thus some undefined opcodes could get emulated as other
(defined but unimplemented) instructions. This corrects the masks.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
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To compile kexec on 32-bit we need a few more bits and pieces. Rather
than add empty definitions, we can make crash.c work on 32-bit, with
only a couple of kludges.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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In the case of a system hang, the user will invoke soft-reset to
initiate the kdump boot. If xmon is enabled, the CPU(s) enter into the
xmon debugger. Unfortunately, the secondary CPU(s) will return to the
hung state when they exit from the debugger (returned from die() ->
system_reset_exception()). This causes a problem in kdump since the
hung CPU(s) will not respond to the IPI sent from kdump. This patch
fixes the issue by calling crash_kexec_secondary() directly from
system_reset_exception() without returning to the previous state. These
secondary CPUs wait 5ms until the kdump boot is started by the primary
CPU. In the case we exited from the debugger to "recover" (command 'x'
in xmon) the primary and the secondary CPUs will all return from die()
-> system_reset_exception() ->crash_kexec_secondary() wait 5ms, then
return to the previous state. A kdump boot is not started in this case.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: David Wilder <dwilder@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Previously the message was "Fatal exception: panic_on_oops", as introduced
in a recent patch whith removed a somewhat dangerous call to ssleep() in
the panic_on_oops path. However, Paul Mackerras suggested that this was
somewhat confusing, leadind people to believe that it was panic_on_oops
that was the root cause of the fatal exception. On his suggestion, this
patch changes the message to simply "Fatal exception". A suitable oops
message should already have been displayed.
Signed-off-by: Simon Horman <horms@verge.net.au>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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This patch is part of an effort to unify the panic_on_oops behaviour across
all architectures that implement it.
It was pointed out to me by Andi Kleen that if an oops has occured in
interrupt context, then calling sleep() in the oops path will only cause a
panic, and that it would be really better for it not to be in the path at
all.
This patch removes the ssleep() call and reworks the console message
accordinly. I have a slght concern that the resulting console message is
too long, feedback welcome.
For powerpc it also unifies the 32bit and 64bit behaviour.
Fror x86_64, this patch only updates the console message, as ssleep() is
already not present.
Signed-off-by: Horms <horms@verge.net.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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With this patch, kdump uses the firmware soft-reset NMI for two purposes:
1) Initiate the kdump (take a crash dump) by issuing a soft-reset.
2) Break a CPU out of a deadlock condition that is detected during kdump
processing.
When a soft-reset is initiated each CPU will enter
system_reset_exception() and set its corresponding bit in the global
bit-array cpus_in_sr then call die(). When die() finds the CPU's bit set
in cpu_in_sr crash_kexec() is called to initiate a crash dump. The first
CPU to enter crash_kexec() is called the "crashing CPU". All other CPUs
are "secondary CPUs". The secondary CPU's pass through to
crash_kexec_secondary() and sleep. The crashing CPU waits for all CPUs
to enter via soft-reset then boots the kdump kernel (see
crash_soft_reset_check())
When the system crashes due to a panic or exception, crash_kexec() is
called by panic() or die(). The crashing CPU sends an IPI to all other
CPUs to notify them of the pending shutdown. If a CPU is in a deadlock
or hung state with interrupts disabled, the IPI will not be delivered.
The result being, that the kdump kernel is not booted. This problem is
solved with the use of a firmware generated soft-reset. After the
crashing_cpu has issued the IPI, it waits for 10 sec for all CPUs to
enter crash_ipi_callback(). A CPU signifies its entry to
crash_ipi_callback() by setting its corresponding bit in the
cpus_in_crash bit array. After 10 sec, if one or more CPUs have not set
their bit in cpus_in_crash we assume that the CPU(s) is deadlocked. The
operator is then prompted to generate a soft-reset to break the
deadlock. Each CPU enters the soft reset handler as described above.
Two conditions must be handled at this point:
1) The system crashed because the operator generated a soft-reset. See
2) The system had crashed before the soft-reset was generated ( in the
case of a Panic or oops).
The first CPU to enter crash_kexec() uses the state of the kexec_lock to
determine this state. If kexec_lock is already held then condition 2 is
true and crash_kexec_secondary() is called, else; this CPU is flagged as
the crashing CPU, the kexec_lock is acquired and crash_kexec() proceeds
as described above.
Each additional CPUs responding to the soft-reset will pass through
crash_kexec() to kexec_secondary(). All secondary CPUs call
crash_ipi_callback() readying them self's for the shutdown. When ready
they clear their bit in cpus_in_sr. The crashing CPU waits in
kexec_secondary() until all other CPUs have cleared their bits in
cpus_in_sr. The kexec kernel boot is then started.
Signed-off-by: Haren Myneni <haren@us.ibm.com>
Signed-off-by: David Wilder <dwilder@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This patch contains a total rewrite of the backlight infrastructure for
portable Apple computers. Backward compatibility is retained. A sysfs
interface allows userland to control the brightness with more steps than
before. Userland is allowed to upload a brightness curve for different
monitors, similar to Mac OS X.
[akpm@osdl.org: add needed exports]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This gives the ability to control whether alignment exceptions get
fixed up or reported to the process as a SIGBUS, using the existing
PR_SET_UNALIGN and PR_GET_UNALIGN prctls. We do not implement the
option of logging a message on alignment exceptions.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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This adds the PowerPC part of the code to allow processes to change
their endian mode via prctl.
This also extends the alignment exception handler to be able to fix up
alignment exceptions that occur in little-endian mode, both for
"PowerPC" little-endian and true little-endian.
We always enter signal handlers in big-endian mode -- the support for
little-endian mode does not amount to the creation of a little-endian
user/kernel ABI. If the signal handler returns, the endian mode is
restored to what it was when the signal was delivered.
We have two new kernel CPU feature bits, one for PPC little-endian and
one for true little-endian. Most of the classic 32-bit processors
support PPC little-endian, and this is reflected in the CPU feature
table. There are two corresponding feature bits reported to userland
in the AT_HWCAP aux vector entry.
This is based on an earlier patch by Anton Blanchard.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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Make machine_check_exception handling code path the same on ppc32 & ppc64.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
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This removes statically assigned platform numbers and reworks the
powerpc platform probe code to use a better mechanism. With this,
board support files can simply declare a new machine type with a
macro, and implement a probe() function that uses the flattened
device-tree to detect if they apply for a given machine.
We now have a machine_is() macro that replaces the comparisons of
_machine with the various PLATFORM_* constants. This commit also
changes various drivers to use the new macro instead of looking at
_machine.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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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 <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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On 32-bit, the exception prolog for the program check exception doesn't
enable interrupts early on. If it is an illegal instruction exception,
we read the instruction in order to emulate certain instructions, and
the get_user of the instruction triggers a WARN_ON since interrupts
are still disabled. This adds a local_irq_enable() to enable
interrupts before reading the instruction.
Signed-off-by: Paul Mackerras <paulus@samba.org>
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