linux.git/arch/powerpc/kernel, branch v2.6.25

[POWERPC] Fix rtas_flash procfs interface

2008-04-03T11:11:11+00:00

Handling of the proc_dir_entry->count was changed in 2.6.24-rc5.
After this change, the default value for pde->count is 1 and not 0 as
before.  Therefore, if we want to check whether our procfs file is
already opened (already in use), we have to check if pde->count is
greater than 2 rather than 1.

Signed-off-by: Maxim Shchetynin 
Signed-off-by: Jens Osterkamp 
Signed-off-by: Paul Mackerras

[POWERPC] Fix iSeries hard irq enabling regression

2008-04-03T11:10:34+00:00

A subtle bug sneaked into iSeries recently.  On this platform, we must
not normally clear MSR:EE (the hardware external interrupt enable)
except for short periods of time.  Taking an interrupt while
soft-disabled doesn't cause us to clear it for example.

The iSeries kernel expects to mostly run with MSR:EE enabled at all
times except in a few exception entry/exit code paths.  Thus
local_irq_enable() doesn't check if it needs to hard-enable as it
expects this to be unnecessary on iSeries.

However, hard_irq_disable() _does_ cause MSR:EE to be cleared,
including on iSeries.  A call to it was recently added to the
context switch code, thus causing interrupts to become disabled
for a long periods of time, causing the iSeries watchdog to kick
in under some circumstances and other nasty things.

This patch fixes it by making local_irq_enable() properly re-enable
MSR:EE on iSeries.  It basically removes a return statement here
to make iSeries use the same code path as everybody else.  That does
mean that we might occasionally get spurious decrementer interrupts
but I don't think that matters.

Another option would have been to make hard_irq_disable() a nop
on iSeries but I didn't like it much, in case we have good reasons
to hard-disable.

Part of the patch is fixes to make sure the hard_enabled PACA field
is properly set on iSeries as it used not to be before, since it
was mostly unused.

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

[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

[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] user_regset PTRACE_SETREGS regression fix

2008-03-19T23:10:56+00:00

The PTRACE_SETREGS request was only recently added on powerpc,
and gdb does not use it.  So it slipped through without getting
all the testing it should have had.

The user_regset changes had a simple bug in storing to all of
the 32-bit general registers block on 64-bit kernels.  This bug
only comes up with PTRACE_SETREGS, not PPC_PTRACE_SETREGS.
It causes a BUG_ON to hit, so this fix needs to go in ASAP.

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

[POWERPC] Export empty_zero_page

2008-03-12T23:09:28+00:00

Once again, this time with feeling....

						- Ted

>From c91cfaabc17f8a53807a2f31f067a732e34a1550 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o 
Date: Wed, 12 Mar 2008 11:50:39 -0400
Subject: Export empty_zero_page

The empty_zero_page symbol is exported by most other architectures
(s390, ia64, x86, um), and an upcoming ext4 patch needs it because
ZERO_PAGE() references empty_zero_page, and we need it to zero out an
unitialized extents in ext4 files.

Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Paul Mackerras

[POWERPC] Fix bogus test for unassigned PCI resources

2008-03-12T23:09:27+00:00

A bogus test for unassigned resources that came from our 32-bit
PCI code ended up being "merged" by my previous patch series,
breaking some 64-bit setups where devices have legal resources
ending at 0xffffffff.

This fixes it by completely changing the test.  We now test for
res->start == 0, as the generic code expects, and we also only
do so on platforms that don't have the PPC_PCI_PROBE_ONLY flag
set, as there are cases of pSeries and iSeries where it could
be a valid value and those can't reassign devices.

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

[POWERPC] Add __ucmpdi2 for 64-bit comparisons in 32-bit kernels

2008-03-12T22:39:55+00:00

Some drivers (such as V4L2) have code that causes gcc to generate
calls to __ucmpdi2 when compiling for 32-bit powerpc, which results
in either a link-time error or a module that can't be loaded, as
we don't currently have a __ucmpdi2.  This adds one so these drivers
can be used.

Signed-off-by: Paul Mackerras

[POWERPC] 8xx: fix swap

2008-03-07T14:42:28+00:00

This makes swap routines operate correctly on the ppc_8xx based machines.
Code has been revalidated on mpc885ads (8M sdram) with recent kernel. Based
on patch from Yuri Tikhonov  to do the same on arch/ppc
instance.

Recent kernel's size makes swap feature very important on low-memory platforms,
those are actually non-operable without it.

Signed-off-by: Yuri Tikhonov 
Signed-off-by: Vitaly Bordug 
Signed-off-by: Kumar Gala

[POWERPC] Fix dt_mem_next_cell() to read the full address

2008-02-20T02:33:37+00:00

dt_mem_next_cell() currently does of_read_ulong().  This does not
allow for the case where #size-cells and/or #address-cells = 2 on a
32-bit system, as it will end up reading 32 bits instead of the
expected 64.  Change it to use of_read_number instead and always
return a u64.

Signed-off-by: Becky Bruce 
Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Paul Mackerras