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  1. 19 6月, 2009 1 次提交
    • S
      function-graph: add stack frame test · 71e308a2
      由 Steven Rostedt 提交于 
      In case gcc does something funny with the stack frames, or the return
from function code, we would like to detect that.

An arch may implement passing of a variable that is unique to the
function and can be saved on entering a function and can be tested
when exiting the function. Usually the frame pointer can be used for
this purpose.

This patch also implements this for x86. Where it passes in the stack
frame of the parent function, and will test that frame on exit.

There was a case in x86_32 with optimize for size (-Os) where, for a
few functions, gcc would align the stack frame and place a copy of the
return address into it. The function graph tracer modified the copy and
not the actual return address. On return from the funtion, it did not go
to the tracer hook, but returned to the parent. This broke the function
graph tracer, because the return of the parent (where gcc did not do
this funky manipulation) returned to the location that the child function
was suppose to. This caused strange kernel crashes.

This test detected the problem and pointed out where the issue was.

This modifies the parameters of one of the functions that the arch
specific code calls, so it includes changes to arch code to accommodate
the new prototype.

Note, I notice that the parsic arch implements its own push_return_trace.
This is now a generic function and the ftrace_push_return_trace should be
used instead. This patch does not touch that code.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
      71e308a2
  3. 18 5月, 2009 2 次提交
  5. 07 4月, 2009 2 次提交
  7. 02 4月, 2009 1 次提交
    • S
      tracing, powerpc: fix powerpc tree and tracing tree interaction · a095bdbb
      由 Stephen Rothwell 提交于 
      Today's linux-next build (powerpc allyesconfig) failed like this:

arch/powerpc/kernel/ftrace.c: In function 'prepare_ftrace_return':
arch/powerpc/kernel/ftrace.c:612: warning: passing argument 3 of 'ftrace_push_return_trace' makes pointer from integer without a cast
arch/powerpc/kernel/ftrace.c:612: error: too many arguments to function 'ftrace_push_return_trace'

Caused by commit 5d1a03dc
("function-graph: moved the timestamp from arch to generic code") from
the tracing tree which (removed an argument from
ftrace_push_return_trace()) interacting with commit
6794c782 ("powerpc64: port of the
function graph tracer") from the powerpc tree.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <linuxppc-dev@ozlabs.org>
LKML-Reference: <20090327230834.93d0221d.sfr@canb.auug.org.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a095bdbb
  9. 23 2月, 2009 9 次提交
  11. 10 2月, 2009 1 次提交
  13. 28 11月, 2008 3 次提交
  15. 21 11月, 2008 4 次提交
  17. 23 10月, 2008 2 次提交
  19. 24 6月, 2008 1 次提交
  21. 10 6月, 2008 1 次提交
  23. 27 5月, 2008 1 次提交
    • S
      ftrace: powerpc clean ups · ccbfac29
      由 Steven Rostedt 提交于 
      This patch cleans up the ftrace code in PowerPC based on the comments from
Michael Ellerman.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: proski@gnu.org
Cc: a.p.zijlstra@chello.nl
Cc: Pekka Paalanen <pq@iki.fi>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: linuxppc-dev@ozlabs.org
Cc: Soeren Sandmann Pedersen <sandmann@redhat.com>
Cc: paulus@samba.org
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      ccbfac29
  25. 24 5月, 2008 6 次提交
    • S
      ftrace: support for PowerPC · 4e491d14
      由 Steven Rostedt 提交于 
      This patch adds full support for ftrace for PowerPC (both 64 and 32 bit).
This includes dynamic tracing and function filtering.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      4e491d14
    • S
      ftrace: fix the fault label in updating code · a56be3fe
      由 Steven Rostedt 提交于 
      The fault label to jump to on fault of updating the code was misplaced
preventing the fault from being recorded.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      a56be3fe
    • S
      ftrace: use dynamic patching for updating mcount calls · d61f82d0
      由 Steven Rostedt 提交于 
      This patch replaces the indirect call to the mcount function
pointer with a direct call that will be patched by the
dynamic ftrace routines.

On boot up, the mcount function calls the ftace_stub function.
When the dynamic ftrace code is initialized, the ftrace_stub
is replaced with a call to the ftrace_record_ip, which records
the instruction pointers of the locations that call it.

Later, the ftraced daemon will call kstop_machine and patch all
the locations to nops.

When a ftrace is enabled, the original calls to mcount will now
be set top call ftrace_caller, which will do a direct call
to the registered ftrace function. This direct call is also patched
when the function that should be called is updated.

All patching is performed by a kstop_machine routine to prevent any
type of race conditions that is associated with modifying code
on the fly.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      d61f82d0
    • S
      ftrace: move memory management out of arch code · 3c1720f0
      由 Steven Rostedt 提交于 
      This patch moves the memory management of the ftrace
records out of the arch code and into the generic code
making the arch code simpler.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      3c1720f0
    • S
      ftrace: use nops instead of jmp · dfa60aba
      由 Steven Rostedt 提交于 
      This patch patches the call to mcount with nops instead
of a jmp over the mcount call.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      dfa60aba
    • S
      ftrace: dynamic enabling/disabling of function calls · 3d083395
      由 Steven Rostedt 提交于 
      This patch adds a feature to dynamically replace the ftrace code
with the jmps to allow a kernel with ftrace configured to run
as fast as it can without it configured.

The way this works, is on bootup (if ftrace is enabled), a ftrace
function is registered to record the instruction pointer of all
places that call the function.

Later, if there's still any code to patch, a kthread is awoken
(rate limited to at most once a second) that performs a stop_machine,
and replaces all the code that was called with a jmp over the call
to ftrace. It only replaces what was found the previous time. Typically
the system reaches equilibrium quickly after bootup and there's no code
patching needed at all.

e.g.

  call ftrace  /* 5 bytes */

is replaced with

  jmp 3f  /* jmp is 2 bytes and we jump 3 forward */
3:

When we want to enable ftrace for function tracing, the IP recording
is removed, and stop_machine is called again to replace all the locations
of that were recorded back to the call of ftrace.  When it is disabled,
we replace the code back to the jmp.

Allocation is done by the kthread. If the ftrace recording function is
called, and we don't have any record slots available, then we simply
skip that call. Once a second a new page (if needed) is allocated for
recording new ftrace function calls.  A large batch is allocated at
boot up to get most of the calls there.

Because we do this via stop_machine, we don't have to worry about another
CPU executing a ftrace call as we modify it. But we do need to worry
about NMI's so all functions that might be called via nmi must be
annotated with notrace_nmi. When this code is configured in, the NMI code
will not call notrace.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      3d083395