linux.git/arch/powerpc/kernel/entry_32.S, branch v3.10

powerpc/32bit:Store temporary result in r0 instead of r8

2013-05-31T22:29:27+00:00

Commit a9c4e541ea9b22944da356f2a9258b4eddcc953b
"powerpc/kprobe: Complete kprobe and migrate exception frame"
introduced a regression:

While returning from exception handling in case of PREEMPT enabled,
_TIF_NEED_RESCHED bit is checked in TI_FLAGS (thread_info flag) of current
task. Only if this bit is set, it should continue with the process of
calling preempt_schedule_irq() to schedule highest priority task if
available.

Current code assumes that r8 contains TI_FLAGS and check this for
_TIF_NEED_RESCHED, but as r8 is modified in the code which executes before
this check, r8 no longer contains the expected TI_FLAGS information.

As a result check for comparison with _TIF_NEED_RESCHED was failing even if
NEED_RESCHED bit is set in the current thread_info flag. Due to this,
preempt_schedule_irq() and in turn scheduler was not getting called even if
highest priority task is ready for execution.

So, store temporary results in r0 instead of r8 to prevent r8 from getting
modified as subsequent code is dependent on its value.

Signed-off-by: Priyanka Jain 
CC:  [v3.7+]
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fix MAX_STACK_TRACE_ENTRIES too low warning again

2013-05-14T04:36:35+00:00

Saw this warning again, and this time from the ret_from_fork path.

It seems we could clear the back chain earlier in copy_thread(), which
could cover both path, and also fix potential lockdep usage in
schedule_tail(), or exception occurred before we clear the back chain.

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

powerpc: Fix MAX_STACK_TRACE_ENTRIES too low warning for ppc32

2013-01-28T23:10:22+00:00

This patch fixes MAX_STACK_TRACE_ENTRIES too low warning for ppc32,
which is similar to commit 12660b17.

Reported-by: Christian Kujau 
Signed-off-by: Li Zhong 
Tested-by: Christian Kujau 
Signed-off-by: Benjamin Herrenschmidt

powerpc: switch to saner kernel_execve() semantics

2012-10-14T23:35:44+00:00

Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal

2012-10-12T01:49:08+00:00

Pull pile 2 of execve and kernel_thread unification work from Al Viro:
 "Stuff in there: kernel_thread/kernel_execve/sys_execve conversions for
  several more architectures plus assorted signal fixes and cleanups.

  There'll be more (in particular, real fixes for the alpha
  do_notify_resume() irq mess)..."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (43 commits)
  alpha: don't open-code trace_report_syscall_{enter,exit}
  Uninclude linux/freezer.h
  m32r: trim masks
  avr32: trim masks
  tile: don't bother with SIGTRAP in setup_frame
  microblaze: don't bother with SIGTRAP in setup_rt_frame()
  mn10300: don't bother with SIGTRAP in setup_frame()
  frv: no need to raise SIGTRAP in setup_frame()
  x86: get rid of duplicate code in case of CONFIG_VM86
  unicore32: remove pointless test
  h8300: trim _TIF_WORK_MASK
  parisc: decide whether to go to slow path (tracesys) based on thread flags
  parisc: don't bother looping in do_signal()
  parisc: fix double restarts
  bury the rest of TIF_IRET
  sanitize tsk_is_polling()
  bury _TIF_RESTORE_SIGMASK
  unicore32: unobfuscate _TIF_WORK_MASK
  mips: NOTIFY_RESUME is not needed in TIF masks
  mips: merge the identical "return from syscall" per-ABI code
  ...

Conflicts:
	arch/arm/include/asm/thread_info.h

powerpc: switch to generic sys_execve()/kernel_execve()

2012-10-01T03:35:51+00:00

the only non-obvious part is that current_pt_regs() is really needed
here - task_pt_regs() is NULL for kernel threads; it's OK for ptrace
uses (the thing task_pt_regs() is intended for), but not for us.

Signed-off-by: Al Viro

powerpc: split ret_from_fork

2012-10-01T03:31:19+00:00

... and get rid of in-kernel syscalls in kernel_thread()

Signed-off-by: Al Viro

powerpc/kprobe: Complete kprobe and migrate exception frame

2012-09-18T05:32:42+00:00

We can't emulate stwu since that may corrupt current exception stack.
So we will have to do real store operation in the exception return code.

Firstly we'll allocate a trampoline exception frame below the kprobed
function stack and copy the current exception frame to the trampoline.
Then we can do this real store operation to implement 'stwu', and reroute
the trampoline frame to r1 to complete this exception migration.

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

powerpc: Set stack limit properly in crit_transfer_to_handler

2012-07-27T01:42:31+00:00

Commit 9778b696a0188ad3b3524b383953ee73b31b7b68 incorrectly
changes the code setting the stack limit on entry to the
kernel to mark the thread_info at the bottom of the stack
out of bounds anymore. This fixes it.

Signed-off-by: Stuart Yoder 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Fixup oddity in entry_32.S

2012-07-11T04:18:33+00:00

When I "fixed" the CONFIG_TRACE_IRQFLAGS case on interrupt entry,
I screwed up a little bit with the test for user space vs. kernel.

The code is fine, there's just some dead code around it. I basically
removed the test and always create the added stack frame whether
coming from user or kernel since in any case we do need to save
a bunch of volatile registers or bad things would happen (we can
take page faults in the kernel for example).

Signed-off-by: Benjamin Herrenschmidt