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  1. 02 Jul, 2011 3 commits
    • Frederic Weisbecker's avatar
      x86,64: Simplify save_regs() · 1871853f
      Frederic Weisbecker authored 
      The save_regs function that saves the regs on low level
irq entry is complicated because of the fact it changes
its stack in the middle and also because it manipulates
data allocated in the caller frame and accesses there
are directly calculated from callee rsp value with the
return address in the middle of the way.

This complicates the static stack offsets calculation and
require more dynamic ones. It also needs a save/restore
of the function's return address.

To simplify and optimize this, turn save_regs() into a
macro.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jan Beulich <JBeulich@novell.com>
      1871853f
    • Frederic Weisbecker's avatar
      x86: Fetch stack from regs when possible in dump_trace() · 47ce11a2
      Frederic Weisbecker authored 
      When regs are passed to dump_stack(), we fetch the frame
pointer from the regs but the stack pointer is taken from
the current frame.

Thus the frame and stack pointers may not come from the same
context. For example this can result in the unwinder to
think the context is in irq, due to the current value of
the stack, but the frame pointer coming from the regs points
to a frame from another place. It then tries to fix up
the irq link but ends up dereferencing a random frame
pointer that doesn't belong to the irq stack:

[ 9131.706906] ------------[ cut here ]------------
[ 9131.707003] WARNING: at arch/x86/kernel/dumpstack_64.c:129 dump_trace+0x2aa/0x330()
[ 9131.707003] Hardware name: AMD690VM-FMH
[ 9131.707003] Perf: bad frame pointer = 0000000000000005 in callchain
[ 9131.707003] Modules linked in:
[ 9131.707003] Pid: 1050, comm: perf Not tainted 3.0.0-rc3+ #181
[ 9131.707003] Call Trace:
[ 9131.707003]  <IRQ>  [<ffffffff8104bd4a>] warn_slowpath_common+0x7a/0xb0
[ 9131.707003]  [<ffffffff8104be21>] warn_slowpath_fmt+0x41/0x50
[ 9131.707003]  [<ffffffff8178b873>] ? bad_to_user+0x6d/0x10be
[ 9131.707003]  [<ffffffff8100c2da>] dump_trace+0x2aa/0x330
[ 9131.707003]  [<ffffffff810107d3>] ? native_sched_clock+0x13/0x50
[ 9131.707003]  [<ffffffff8101b164>] perf_callchain_kernel+0x54/0x70
[ 9131.707003]  [<ffffffff810d391f>] perf_prepare_sample+0x19f/0x2a0
[ 9131.707003]  [<ffffffff810d546c>] __perf_event_overflow+0x16c/0x290
[ 9131.707003]  [<ffffffff810d5430>] ? __perf_event_overflow+0x130/0x290
[ 9131.707003]  [<ffffffff810107d3>] ? native_sched_clock+0x13/0x50
[ 9131.707003]  [<ffffffff8100fbb9>] ? sched_clock+0x9/0x10
[ 9131.707003]  [<ffffffff810752e5>] ? T.375+0x15/0x90
[ 9131.707003]  [<ffffffff81084da4>] ? trace_hardirqs_on_caller+0x64/0x180
[ 9131.707003]  [<ffffffff810817bd>] ? trace_hardirqs_off+0xd/0x10
[ 9131.707003]  [<ffffffff810d5764>] perf_event_overflow+0x14/0x20
[ 9131.707003]  [<ffffffff810d588c>] perf_swevent_hrtimer+0x11c/0x130
[ 9131.707003]  [<ffffffff817821a1>] ? error_exit+0x51/0xb0
[ 9131.707003]  [<ffffffff81072e93>] __run_hrtimer+0x83/0x1e0
[ 9131.707003]  [<ffffffff810d5770>] ? perf_event_overflow+0x20/0x20
[ 9131.707003]  [<ffffffff81073256>] hrtimer_interrupt+0x106/0x250
[ 9131.707003]  [<ffffffff812a3bfd>] ? trace_hardirqs_off_thunk+0x3a/0x3c
[ 9131.707003]  [<ffffffff81024833>] smp_apic_timer_interrupt+0x53/0x90
[ 9131.707003]  [<ffffffff81789053>] apic_timer_interrupt+0x13/0x20
[ 9131.707003]  <EOI>  [<ffffffff817821a1>] ? error_exit+0x51/0xb0
[ 9131.707003]  [<ffffffff8178219c>] ? error_exit+0x4c/0xb0
[ 9131.707003] ---[ end trace b2560d4876709347 ]---

Fix this by simply taking the stack pointer from regs->sp
when regs are provided.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      47ce11a2
    • Frederic Weisbecker's avatar
      x86: Save stack pointer in perf live regs savings · 9e46294d
      Frederic Weisbecker authored 
      In order to prepare for fetching the stack pointer from the
regs when possible in dump_trace() instead of taking the
local one, save the current stack pointer in perf live regs saving.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      9e46294d
  3. 16 Jun, 2011 2 commits
  5. 13 Jun, 2011 10 commits
  7. 12 Jun, 2011 8 commits
  9. 11 Jun, 2011 16 commits
  11. 10 Jun, 2011 1 commit
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