linux.git/arch/powerpc/kernel/process.c, branch v2.6.26-rc7

[POWERPC] Add IRQSTACKS support on ppc32

2008-04-29T05:57:34+00:00

This makes it possible to use separate stacks for hard and soft IRQs
on 32-bit powerpc as well as on 64-bit.  The code for 32-bit is just
the 32-bit analog of the 64-bit code.

* Added allocation and initialization of the irq stacks.  We limit the
  stacks to be in lowmem for ppc32.
* Implemented ppc32 versions of call_do_softirq() and call_handle_irq()
  to switch the stack pointers
* Reworked how we do stack overflow detection.  We now keep around the
  limit of the stack in the thread_struct and compare against the limit
  to see if we've overflowed.  We can now use this on ppc64 if desired.

[ paulus@samba.org: Fixed bug on 6xx where we need to reload r9 with the
  thread_info pointer. ]

Signed-off-by: Kumar Gala 
Signed-off-by: Paul Mackerras

[POWERPC] Fix kernel stack allocation alignment

2008-04-24T10:57:33+00:00

The powerpc kernel stacks need to be naturally aligned, as they
contain the thread info at the bottom, which is obtained by
clearing the low bits of the stack pointer.

However, when using 64K pages, the stack is smaller than a page,
so we use kmalloc to allocate it, but that doesn't provide the
alignment guarantee we need.

It appeared to work so far... until one enables SLUB debugging
which then returns unaligned pointers.  Ooops...

This fixes it by using a slab cache with enforced alignment.  It
relies on my previous patch that adds a thread_info_cache_init()
callback.

Signed-off-by: Benjamin Herrenschmidt 
Acked-by: Andrew Morton 
Signed-off-by: Paul Mackerras

[POWERPC] Move stackframe definitions to common header

2008-04-18T05:37:18+00:00

This moves various definitions used all over the place to parse stack
frames to ptrace.h so only one definition is needed.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras

Merge branch 'linux-2.6'

2008-04-14T11:11:02+00:00

[POWERPC] Fix missed hardware breakpoints across multiple threads

2008-03-28T11:51:02+00:00

There is a bug in the powerpc DABR (data access breakpoint) handling,
which can result in us missing breakpoints if several threads are trying
to break on the same address.

The circumstances are that do_page_fault() calls do_dabr(), this clears
the DABR (sets it to 0) and sets up the signal which will report to
userspace that the DABR was hit. The do_signal() code will restore the DABR
value on the way out to userspace.

If we reschedule before calling do_signal(), __switch_to() will check the
cached DABR value and compare it to the new thread's value, if they match
we don't set the DABR in hardware.

So if two threads have the same DABR value, and we schedule from one to
the other after taking the interrupt for the first thread hitting the DABR,
the second thread will run without the DABR set in hardware.

The cleanest fix is to move the cache update into set_dabr(), that way we
can't forget to do it.

Reported-by: Jan Kratochvil 
Signed-off-by: Michael Ellerman 
Signed-off-by: Paul Mackerras

Merge branch 'linux-2.6'

2008-03-25T21:44:18+00:00

[POWERPC] Don't touch PT_DTRACE in exec

2008-03-25T21:44:05+00:00

The PT_DTRACE flag is meaningless and obsolete.
Don't touch it.

Signed-off-by: Roland McGrath 
Signed-off-by: Paul Mackerras

[POWERPC] Fix PMU + soft interrupt disable bug

2008-03-19T23:14:55+00:00

Since the PMU is an NMI now, it can come at any time we are only soft
disabled.  We must hard disable around the two places we allow the kernel
stack SLB and r1 to go out of sync.  Otherwise the PMU exception can
force a kernel stack SLB into another slot, which can lead to it
getting evicted, which can lead to a nasty unrecoverable SLB miss
in the exception entry code.

Signed-off-by: Anton Blanchard 
Acked-by: Benjamin Herrenschmidt 
Acked-by: Olof Johansson 
Signed-off-by: Paul Mackerras

[POWERPC] Fix DEBUG_PREEMPT warning when warning

2008-02-14T11:11:00+00:00

The powerpc show_regs prints CPU using smp_processor_id: change that to
raw_smp_processor_id, so that when it's showing a WARN_ON backtrace without
preemption disabled, DEBUG_PREEMPT doesn't mess up that warning with its own.

Signed-off-by: Hugh Dickins 
Signed-off-by: Paul Mackerras

[POWERPC] Fix hardware IRQ time accounting problem.

2007-12-06T05:08:59+00:00

The commit fa13a5a1f25f671d084d8884be96fc48d9b68275 (sched: restore
deterministic CPU accounting on powerpc), unconditionally calls
update_process_tick() in system context.  In the deterministic
accounting case this is the correct thing to do.  However, in the
non-deterministic accounting case we need to not do this, since doing
this results in the time accounted as hardware irq time being
artificially elevated.

Also this collapses 2 consecutive '#ifdef CONFIG_VIRT_CPU_ACCOUNTING'
checks in time.h into one for neatness.

Signed-off-by: Tony Breeds 
Signed-off-by: Paul Mackerras