linux-toradex.git/kernel/trace/trace_ksym.c, branch imx-android-r10.4

hw-breakpoints: Get the number of available registers on boot dynamically

2010-05-01T02:32:14+00:00

The breakpoint generic layer assumes that archs always know in advance
the static number of address registers available to host breakpoints
through the HBP_NUM macro.

However this is not true for every archs. For example Arm needs to get
this information dynamically to handle the compatiblity between
different versions.

To solve this, this patch proposes to drop the static HBP_NUM macro
and let the arch provide the number of available slots through a
new hw_breakpoint_slots() function. For archs that have
CONFIG_HAVE_MIXED_BREAKPOINTS_REGS selected, it will be called once
as the number of registers fits for instruction and data breakpoints
together.
For the others it will be called first to get the number of
instruction breakpoint registers and another time to get the
data breakpoint registers, the targeted type is given as a
parameter of hw_breakpoint_slots().

Reported-by: Will Deacon 
Signed-off-by: Frederic Weisbecker 
Acked-by: Paul Mundt 
Cc: Mahesh Salgaonkar 
Cc: K. Prasad 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Jason Wessel 
Cc: Ingo Molnar

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

ksym_tracer: Remove trace_stat

2009-12-30T06:50:50+00:00

trace_stat is problematic. Don't use it, use seqfile instead.

This fixes a race that reading the stat file is not protected by
any lock, which can lead to use after free.

Signed-off-by: Li Zefan 
Cc: Steven Rostedt 
Cc: K.Prasad 
Cc: Frederic Weisbecker 
LKML-Reference: <4B3AF203.40200@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

ksym_tracer: Fix race when incrementing count

2009-12-30T06:50:49+00:00

We are under rcu read section but not holding the write lock, so
count++ is not atomic. Use atomic64_t instead.

Signed-off-by: Li Zefan 
Cc: Steven Rostedt 
Cc: K.Prasad 
Cc: Frederic Weisbecker 
LKML-Reference: <4B3AF1EC.9010608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

ksym_tracer: Fix to allow writing newline to ksym_trace_filter

2009-12-30T06:50:49+00:00

It used to work, but now doesn't:

 # echo > ksym_filter
 bash: echo: write error: Invalid argument

It's caused by d954fbf0ff6b5fdfb32350e85a2f15d3db976506
("tracing: Fix wrong usage of strstrip in trace_ksyms").

Signed-off-by: Li Zefan 
Cc: Steven Rostedt 
Cc: K.Prasad 
Cc: Frederic Weisbecker 
LKML-Reference: <4B3AF1D7.5040400@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

ksym_tracer: Fix to make the tracer work

2009-12-30T06:50:47+00:00

ksym tracer doesn't work:

 # echo tasklist_lock:rw- > ksym_trace_filter
 -bash: echo: write error: No such device

It's because we pass to perf_event_create_kernel_counter()
a cpu number which is not present.

Signed-off-by: Li Zefan 
Cc: Steven Rostedt 
Cc: K.Prasad 
Cc: Frederic Weisbecker 
LKML-Reference: <4B3AF19E.1010201@cn.fujitsu.com>
Signed-off-by: Ingo Molnar

Merge branch 'linus' into tracing/urgent

2009-12-14T08:16:49+00:00

Conflicts:
	kernel/trace/trace_kprobe.c

Merge reason: resolve the conflict.

Signed-off-by: Ingo Molnar

ksym_tracer: Fix bad cast

2009-12-13T17:46:54+00:00

Fix this warning:

kernel/trace/trace_ksym.c: In function 'ksym_trace_filter_read':
kernel/trace/trace_ksym.c:239: warning: cast to pointer from integer of different size

Signed-off-by: Li Zefan 
Acked-by: Steven Rostedt 
Cc: "K.Prasad" 
LKML-Reference: <4B1DC578.9020909@cn.fujitsu.com>
[remove the strstrip fix as tglx already fixed that]
Signed-off-by: Frederic Weisbecker

tracing: Fix wrong usage of strstrip in trace_ksyms

2009-12-10T23:01:36+00:00

strstrip returns a pointer to the first non space character, but the
code in parse_ksym_trace_str() ignores that.

strstrip is now must_check and therefor we get the correct warning:
kernel/trace/trace_ksym.c:294: warning:
ignoring return value of ‘strstrip’, declared with attribute warn_unused_result

We are really not interested in leading whitespace here.

Fix that and cleanup the dozen kfree() exit pathes.

Signed-off-by: Thomas Gleixner 
Cc: Xiao Guangrong 
Cc: Steven Rostedt

hw-breakpoints: Use overflow handler instead of the event callback

2009-12-06T07:27:18+00:00

struct perf_event::event callback was called when a breakpoint
triggers. But this is a rather opaque callback, pretty
tied-only to the breakpoint API and not really integrated into perf
as it triggers even when we don't overflow.

We prefer to use overflow_handler() as it fits into the perf events
rules, being called only when we overflow.

Reported-by: Peter Zijlstra 
Signed-off-by: Frederic Weisbecker 
Cc: Paul Mackerras 
Cc: Arnaldo Carvalho de Melo 
Cc: "K. Prasad"