linux-stable.git/arch/mips/kernel, branch v3.8

MIPS: Function tracer: Fix broken function tracing

2013-01-31T14:28:48+00:00

Function tracing is currently broken for all 32 bit MIPS platforms.
When tracing is enabled, the kernel immediately hangs on boot.
This is a result of commit b732d439cb43336cd6d7e804ecb2c81193ef63b0
that changes the kernel/trace/Kconfig file so that is no longer
forces FRAME_POINTER when FUNCTION_TRACING is enabled.

MIPS frame pointers are generally considered to be useless because
they cannot be used to unwind the stack. Unfortunately the MIPS
function tracing code has bugs that are masked by the use of frame
pointers. This commit fixes the bugs so that MIPS frame pointers
don't need to be enabled.

The bugs are a result of the odd calling sequence used to call the trace
routine. This calling sequence is inserted into every traceable function
when the tracing CONFIG option is enabled. This sequence is generated
for 32bit MIPS platforms by the compiler via the "-pg" flag.

Part of the sequence is "addiu sp,sp,-8" in the delay slot after every
call to the trace routine "_mcount" (some legacy thing where 2 arguments
used to be pushed on the stack). The _mcount routine is expected to
adjust the sp by +8 before returning.  So when not disabled, the original
jalr and addiu will be there, so _mcount has to adjust sp.

The problem is that when tracing is disabled for a function, the
"jalr _mcount" instruction is replaced with a nop, but the
"addiu sp,sp,-8" is still executed and the stack pointer is left
trashed. When frame pointers are enabled the problem is masked
because any access to the stack is done through the frame
pointer and the stack pointer is restored from the frame pointer when
the function returns.

This patch writes two nops starting at the address of the "jalr _mcount"
instruction whenever tracing is disabled. This means that the
"addiu sp,sp.-8" will be converted to a nop along with the "jalr".  When
disabled, there will be two nops.

This is SMP safe because the first time this happens is during
ftrace_init() which is before any other processor has been started.
Subsequent calls to enable/disable tracing when other CPUs ARE running
will still be safe because the enable will only change the first nop
to a "jalr" and the disable, while writing 2 nops, will only be changing
the "jalr". This patch also stops using stop_machine() to call the
tracer enable/disable routines and calls them directly because the
routines are SMP safe.

When the kernel first boots we have to be able to handle the gcc
generated jalr, addui sequence until ftrace_init gets a chance to run
and change the sequence. At this point mcount just adjusts the stack
and returns. When ftrace_init runs, we convert the jalr/addui to nops.
Then whenever tracing is enabled we convert the first nop to a "jalr
mcount+8". The mcount+8 entry point skips the stack adjust.

[ralf@linux-mips.org: Folded in  Steven Rostedt's build fix.]

Signed-off-by: Al Cooper 
Cc: rostedt@goodmis.org
Cc: ddaney.cavm@gmail.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/4806/
Patchwork: https://patchwork.linux-mips.org/patch/4841/
Signed-off-by: Ralf Baechle

MIPS: vpe.c: Fix null pointer dereference in print arguments.

2013-01-16T15:29:23+00:00

In the printk, the variable t euqals to NULL, so there is no t->index.
Use v->tc->index instead.

[ralf@linux-mips.org: Use opportunity of changing this line anyway to make
this line whitespacely correct.]

Signed-off-by: Cong Ding 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/4792/
Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2013-01-07T15:50:41+00:00

Pull MIPS fixes from Ralf Baechle:
 "Various fixes across the tree.  The modpost error due to
  virt_addr_valid() not being usable from modules required a number of
  preparatory cleanups so a clean fix was possible."

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: 64-bit: Fix build if !CONFIG_MODULES
  MIPS: Wire up finit_module syscall.
  MIPS: Fix modpost error in modules attepting to use virt_addr_valid().
  MIPS: page.h: Remove now unnecessary #ifndef __ASSEMBLY__ wrapper.
  MIPS: Switch remaining assembler PAGE_SIZE users to .
  MIPS: Include PAGE_S{IZE,HIFT} in .
  MIPS: Don't include  unnecessarily.
  MIPS: Fix comment.
  Revert "MIPS: Optimise TLB handlers for MIPS32/64 R2 cores."
  MIPS: perf: Fix build failure in XLP perf support.
  MIPS: Alchemy: Make 32kHz and r4k timer coexist peacefully

MIPS: drivers: remove __dev* attributes.

2013-01-03T23:57:09+00:00

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, __devinitdata,
and __devexit from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton 
Signed-off-by: Greg Kroah-Hartman

MIPS: Wire up finit_module syscall.

2012-12-28T16:04:38+00:00

Signed-off-by: Ralf Baechle

MIPS: Switch remaining assembler PAGE_SIZE users to .

2012-12-28T16:04:16+00:00

Signed-off-by: Ralf Baechle

MIPS: Include PAGE_S{IZE,HIFT} in .

2012-12-28T16:04:10+00:00

Signed-off-by: Ralf Baechle

MIPS: Don't include unnecessarily.

2012-12-28T16:04:04+00:00

So far we're jumping through hoops to keep the file usable from assembler
source but it's getting just too painful.  Turns out that many uses of
 are unnecessary anyway, so just remove those.

Signed-off-by: Ralf Baechle

MIPS: perf: Fix build failure in XLP perf support.

2012-12-27T15:27:35+00:00

Commit 4be3d2f3966b9f010bb997dcab25e7af489a841e ("MIPS: perf: Add XLP
support for hardware perf.") added UNSUPPORTED_PERF_EVENT_ID which was
removed a while back.

Cc: Zi Shen Lim 
Cc: Jayachandran C 
Cc: Linux-MIPS 
Cc: John Crispin 
Cc: Zi Shen Lim 
Signed-off-by: Manuel Lauss 
Acked-by: Jayachandran C 
Patchwork: https://patchwork.linux-mips.org/patch/4730/
Signed-off-by: Ralf Baechle

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2012-12-14T22:27:45+00:00

Pull MIPS updates from Ralf Baechle:
 "The MIPS bits for 3.8.  This also includes a bunch fixes that were
  sitting in the linux-mips.org git tree for a long time.  This pull
  request contains updates to several OCTEON drivers and the board
  support code for BCM47XX, BCM63XX, XLP, XLR, XLS, lantiq, Loongson1B,
  updates to the SSB bus support, MIPS kexec code and adds support for
  kdump.

  When pulling this, there are two expected merge conflicts in
  include/linux/bcma/bcma_driver_chipcommon.h which are trivial to
  resolve, just remove the conflict markers and keep both alternatives."

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (90 commits)
  MIPS: PMC-Sierra Yosemite: Remove support.
  VIDEO: Newport Fix console crashes
  MIPS: wrppmc: Fix build of PCI code.
  MIPS: IP22/IP28: Fix build of EISA code.
  MIPS: RB532: Fix build of prom code.
  MIPS: PowerTV: Fix build.
  MIPS: IP27: Correct fucked grammar in ops-bridge.c
  MIPS: Highmem: Fix build error if CONFIG_DEBUG_HIGHMEM is disabled
  MIPS: Fix potencial corruption
  MIPS: Fix for warning from FPU emulation code
  MIPS: Handle COP3 Unusable exception as COP1X for FP emulation
  MIPS: Fix poweroff failure when HOTPLUG_CPU configured.
  MIPS: MT: Fix build with CONFIG_UIDGID_STRICT_TYPE_CHECKS=y
  MIPS: Remove unused smvp.h
  MIPS/EDAC: Improve OCTEON EDAC support.
  MIPS: OCTEON: Add definitions for OCTEON memory contoller registers.
  MIPS: OCTEON: Add OCTEON family definitions to octeon-model.h
  ata: pata_octeon_cf: Use correct byte order for DMA in when built little-endian.
  MIPS/OCTEON/ata: Convert pata_octeon_cf.c to use device tree.
  MIPS: Remove usage of CEVT_R4K_LIB config option.
  ...