linux-toradex.git/arch/powerpc/kernel/ftrace.c, branch v3.4.2

powerpc/ftrace: Implement raw syscall tracepoints on PowerPC

2011-05-26T03:38:57+00:00

This patch implements the raw syscall tracepoints on PowerPC and exports
them for ftrace syscalls to use.

To minimise reworking existing code, I slightly re-ordered the thread
info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit
within the 16 bits of the andi. instruction's UI field. The instructions
in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the
_TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing
is enabled.

In the case of 64bit PowerPC, arch_syscall_addr and
arch_syscall_match_sym_name are overridden to allow ftrace syscalls to
work given the unusual system call table structure and symbol names that
start with a period.

Signed-off-by: Ian Munsie 
Signed-off-by: Benjamin Herrenschmidt

Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-06-20T17:56:46+00:00

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (24 commits)
  tracing/urgent: warn in case of ftrace_start_up inbalance
  tracing/urgent: fix unbalanced ftrace_start_up
  function-graph: add stack frame test
  function-graph: disable when both x86_32 and optimize for size are configured
  ring-buffer: have benchmark test print to trace buffer
  ring-buffer: do not grab locks in nmi
  ring-buffer: add locks around rb_per_cpu_empty
  ring-buffer: check for less than two in size allocation
  ring-buffer: remove useless compile check for buffer_page size
  ring-buffer: remove useless warn on check
  ring-buffer: use BUF_PAGE_HDR_SIZE in calculating index
  tracing: update sample event documentation
  tracing/filters: fix race between filter setting and module unload
  tracing/filters: free filter_string in destroy_preds()
  ring-buffer: use commit counters for commit pointer accounting
  ring-buffer: remove unused variable
  ring-buffer: have benchmark test handle discarded events
  ring-buffer: prevent adding write in discarded area
  tracing/filters: strloc should be unsigned short
  tracing/filters: operand can be negative
  ...

Fix up kmemcheck-induced conflict in kernel/trace/ring_buffer.c manually

function-graph: add stack frame test

2009-06-18T22:40:18+00:00

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 
Cc: Paul Mackerras 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Cc: Frederic Weisbecker 
Cc: Helge Deller 
Cc: Kyle McMartin 
Signed-off-by: Steven Rostedt

powerpc/ftrace: Use PPC_INST_NOP directly

2009-06-02T00:36:53+00:00

There's no need to wrap PPC_INST_NOP in a static inline.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Remove unused macros

2009-06-02T00:36:46+00:00

These macros were used in the original port, but since commit
e4486fe316 (ftrace, use probe_kernel API to modify code) they
are unused.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Use ppc_function_entry() instead of GET_ADDR

2009-06-02T00:36:32+00:00

Use ppc_function_entry() from code-patching.h.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Fix constraint to be early clobber

2009-05-18T05:19:05+00:00

After upgrading my distcc boxes from gcc 4.2.2 to 4.4.0, the function
graph tracer broke. This was discovered on my x86 boxes.

The issue is that gcc used the same register for an output as it did for
an input in an asm statement. I first thought this was a bug in gcc and
reported it. I was notified that gcc was correct and that the output had
to be flagged as an "early clobber".

I noticed that powerpc had the same issue and this patch fixes it.

Signed-off-by: Steven Rostedt 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Use pr_devel() in ftrace.c

2009-05-18T05:19:04+00:00

pr_debug() can now result in code being generated even when #DEBUG
is not defined. That's not really desirable in the ftrace code
which we want to be snappy.

With CONFIG_DYNAMIC_DEBUG=y:

size before:
   text	   data	    bss	    dec	    hex	filename
   3334	    672	      4	   4010	    faa	arch/powerpc/kernel/ftrace.o

size after:
   text	   data	    bss	    dec	    hex	filename
   2616	    360	      4	   2980	    ba4	arch/powerpc/kernel/ftrace.o

Signed-off-by: Michael Ellerman 
Acked-by: Steven Rostedt 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Fix printf format warning

2009-04-07T05:19:00+00:00

'tramp' is an unsigned long, so print it with %lx.

Fixes the following build warning:
arch/powerpc/kernel/ftrace.c:291: error: format ‘%x’ expects type ‘unsigned int’, but argument 2 has type ‘long unsigned int’

Signed-off-by: Michael Ellerman 
Acked-by: Steven Rostedt 
Signed-off-by: Paul Mackerras

powerpc/ftrace: Fix #if that should be #ifdef

2009-04-07T05:19:00+00:00

Commit bb7253403f7a4670a128e4c080fd8ea1bd4d5029 ("powerpc64,
ftrace: save toc only on modules for function graph"), added an
#if CONFIG_PPC64.  This changes it to #ifdef.

Fixes the following warning on 32-bit builds:
 arch/powerpc/kernel/ftrace.c:562:5: error: "CONFIG_PPC64" is not defined

Signed-off-by: Michael Ellerman 
Acked-by: Steven Rostedt 
Signed-off-by: Paul Mackerras