[RFC GIT PULL] x86 entry / perf stacktrace changes

[Frederic Weisbecker <fweisbec@gmail.com>]

Ingo,

Please pull the perf/stacktrace branch that can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing.git
	perf/stacktrace

Or may be not yet. It's still in RFC because I would like
to ensure I did not break cfi annotations. I hope Jan beulich
or others can have a look.

Sorry to mess up irq entry and perf stacktrace changes in the same
topic. But the changes happen to be very interconnected.

Several cleanups, fixes and optimizations for the x86-64
stacktraces and irq entry.

Last patch seems to add a bit of overhead in the irq entry
(one more "push") but given the changes made in previous
patches, the end result is a more optimized and more clear irq
entry.

Thanks,
	Frederic
---

Frederic Weisbecker (6):
      x86: Save stack pointer in perf live regs savings
      x86: Fetch stack from regs when possible in dump_trace()
      x86,64: Simplify save_regs()
      x86,64: Separate arg1 from rbp handling in SAVE_REGS_IRQ
      x86: Remove useless unwinder backlink from irq regs saving
      x86: Don't use frame pointer to save old stack on irq entry


 arch/x86/include/asm/perf_event.h |    5 +++
 arch/x86/kernel/dumpstack_64.c    |   37 +++-----------------
 arch/x86/kernel/entry_64.S        |   69 ++++++++++++++++--------------------
 3 files changed, 41 insertions(+), 70 deletions(-)