linux-stable.git/arch/powerpc/kernel, branch v3.5

powerpc: Fix build of some debug irq code

2012-07-10T09:16:20+00:00

There was a typo, checking for CONFIG_TRACE_IRQFLAG instead of
CONFIG_TRACE_IRQFLAGS causing some useful debug code to not be
built

This in turns causes a build error on BookE 64-bit due to incorrect
semicolons at the end of a couple of macros, so let's fix that too

Signed-off-by: Benjamin Herrenschmidt 
CC: stable@vger.kernel.org [v3.4]

powerpc: More fixes for lazy IRQ vs. idle

2012-07-10T09:16:07+00:00

Looks like we still have issues with pSeries and Cell idle code
vs. the lazy irq state. In fact, the reset fixes that went upstream
are exposing the problem more by causing BUG_ON() to trigger (which
this patch turns into a WARN_ON instead).

We need to be careful when using a variant of low power state that
has the side effect of turning interrupts back on, to properly set
all the SW & lazy state to look as if everything is enabled before
we enter the low power state with MSR:EE off as we will return with
MSR:EE on. If not, we have a discrepancy of state which can cause
things to go very wrong later on.

This patch moves the logic into a helper and uses it from the
pseries and cell idle code. The power4/970 idle code already got
things right (in assembly even !) so I'm not touching it. The power7
"bare metal" idle code is subtly different and correct. Remains PA6T
and some hypervisor based Cell platforms which have questionable
code in there, but they are mostly dead platforms so I'll fix them
when I manage to get final answers from the respective maintainers
about how the low power state actually works on them.

Signed-off-by: Benjamin Herrenschmidt 
CC: stable@vger.kernel.org [v3.4]

powerpc/ftrace: Do not trace restore_interrupts()

2012-06-29T04:35:36+00:00

As I was adding code that affects all archs, I started testing function
tracer against PPC64 and found that it currently locks up with 3.4
kernel. I figured it was due to tracing a function that shouldn't be, so
I went through the following process to bisect to find the culprit:

 cat /debug/tracing/available_filter_functions > t
 num=`wc -l t`
 sed -ne "1,${num}p" t > t1
 let num=num+1
 sed -ne "${num},$p" t > t2
 cat t1 > /debug/tracing/set_ftrace_filter
 echo function /debug/tracing/current_tracer
 

It finally came down to this function: restore_interrupts()

I'm not sure why this locks up the system. It just seems to prevent
scheduling from occurring. Interrupts seem to still work, as I can ping
the box. But all user processes freeze.

When restore_interrupts() is not traced, function tracing works fine.

Cc: stable@kernel.org
Signed-off-by: Steven Rostedt 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix Section mismatch warnings in prom_init.c

2012-06-29T04:35:36+00:00

This patches tries to fix a couple of Section mismatch warnings like
following one:

WARNING: arch/powerpc/kernel/built-in.o(.text+0x2923c): Section mismatch
in reference from the function .prom_query_opal() to the
function .init.text:.call_prom()
The function .prom_query_opal() references
the function __init .call_prom().
This is often because .prom_query_opal lacks a __init
annotation or the annotation of .call_prom is wrong.

Signed-off-by: Li Zhong 
Signed-off-by: Benjamin Herrenschmidt

ppc64: fix missing to check all bits of _TIF_USER_WORK_MASK in preempt

2012-06-29T04:35:35+00:00

In entry_64.S version of ret_from_except_lite, you'll notice that
in the !preempt case, after we've checked MSR_PR we test for any
TIF flag in _TIF_USER_WORK_MASK to decide whether to go to do_work
or not. However, in the preempt case, we do a convoluted trick to
test SIGPENDING only if PR was set and always test NEED_RESCHED ...
but we forget to test any other bit of _TIF_USER_WORK_MASK !!! So
that means that with preempt, we completely fail to test for things
like single step, syscall tracing, etc...

This should be fixed as the following path:

 - Test PR. If not set, go to resume_kernel, else continue.

 - If go resume_kernel, to do that original do_work.

 - If else, then always test for _TIF_USER_WORK_MASK to decide to do
that original user_work, else restore directly.

Signed-off-by: Tiejun Chen 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix kernel panic during kernel module load

2012-06-08T09:59:08+00:00

This fixes a problem which can causes kernel oopses while loading
a kernel module.

According to the PowerPC EABI specification, GPR r11 is assigned
the dedicated function to point to the previous stack frame.
In the powerpc-specific kernel module loader, do_plt_call()
(in arch/powerpc/kernel/module_32.c), GPR r11 is also used
to generate trampoline code.

This combination crashes the kernel, in the case where the compiler
chooses to use a helper function for saving GPRs on entry, and the
module loader has placed the .init.text section far away from the
.text section, meaning that it has to generate a trampoline for
functions in the .init.text section to call the GPR save helper.
Because the trampoline trashes r11, references to the stack frame
using r11 can cause an oops.

The fix just uses GPR r12 instead of GPR r11 for generating the
trampoline code.  According to the statements from Freescale, this is
safe from an EABI perspective.

I've tested the fix for kernel 2.6.33 on MPC8541.

Cc: stable@vger.kernel.org
Signed-off-by: Steffen Rumler 
[paulus@samba.org: reworded the description]
Signed-off-by: Paul Mackerras

powerpc/time: Sanity check of decrementer expiration is necessary

2012-06-08T04:07:35+00:00

This reverts 68568add2c ("powerpc/time: Remove unnecessary sanity check
of decrementer expiration").  We do need to check whether we have reached
the expiration time of the next event, because we sometimes get an early
decrementer interrupt, most notably when we set the decrementer to 1 in
arch_irq_work_raise().  The effect of not having the sanity check is that
if timer_interrupt() gets called early, we leave the decrementer set to
its maximum value, which means we then don't get any more decrementer
interrupts for about 4 seconds (or longer, depending on timebase
frequency).  I saw these pauses as a consequence of getting a stray
hypervisor decrementer interrupt left over from exiting a KVM guest.

This isn't quite a straight revert because of changes to the surrounding
code, but it restores the same algorithm as was previously used.

Cc: stable@vger.kernel.org
Acked-by: Anton Blanchard 
Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

new helper: signal_delivered()

2012-06-01T16:58:52+00:00

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: Al Viro

powerpc: get rid of restore_sigmask()

2012-06-01T16:58:51+00:00

... it's just a call of set_current_blocked() now

Signed-off-by: Al Viro

most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from set

2012-06-01T16:58:51+00:00

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: Al Viro