Commit Graph

64 Commits

Author SHA1 Message Date
Will Deacon
660d13296b perf tools: Fix build breakage on arm64 targets
Attempting to build the perf tool for an arm64 target results in the
following failure:

  arch/arm64/util/unwind-libunwind.c: In function 'libunwind__arch_reg_id':
  arch/arm64/util/unwind-libunwind.c:77:3: error: implicit declaration of function 'pr_err'
     pr_err("unwind: invalid reg id %d\n", regnum);
     ^
  arch/arm64/util/unwind-libunwind.c:77:3: error: nested extern declaration of 'pr_err'

This is due to commit 84f5d36f48 ("perf tools: Move pr_* debug macros
into debug object") moving the pr_* macros into a new header file, but
failing to update architectures other than x86.

This patch adds the missing include, and fixes the build again.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1412076432-22045-1-git-send-email-will.deacon@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-10-01 14:44:17 -03:00
Stephane Eranian
29a3ce31c3 perf tool: fix compilation for ARM
This patch fixes ARM compile of the perf tool.  The debug.h header file
was missing from a couple of unwind related modules.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140905042103.GA3091@quad
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-09-17 17:08:09 -03:00
Anton Blanchard
65ccb4faae perf tools powerpc: Fix build issue when DWARF support is disabled
The powerpc skip callchain code uses DWARF, so we must disable it if
DWARF is disabled.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20140825182506.2be6512d@kryten
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-09-17 17:08:07 -03:00
Sukadev Bhattiprolu
ad7e767a72 perf tools powerpc: Explicitly include util/debug.h
Looks like util/debug.h was indirectly included before and is no longer
included now. pr_debug is left undefined and the build of perf tool
fails on Powerpc.

Explicitly include util/debug.h.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Link: http://lkml.kernel.org/r/20140807072700.GA17623@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-08-20 08:29:10 -03:00
Elliott Hughes
c4d2df495c perf tools: Add arm64 triplets
Adds the triplet used for arm64 by Android. Others will want to add
their own later.

Signed-off-by: Elliott Hughes <enh@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20140814193920.A7D2D20572@enh.mtv.corp.google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-08-15 10:40:11 -03:00
Mark Salter
7d885749b6 perf tools: Fix arm64 build error
I'm seeing the following build error on arm64:

  In file included from util/event.c:3:0:
  util/event.h:95:17: error: 'PERF_REGS_MAX' undeclared here (not in a function)
    u64 cache_regs[PERF_REGS_MAX];
                 ^

This patch adds a PERF_REGS_MAX definition for arm64.

Signed-off-by: Mark Salter <msalter@redhat.com>
Acked-by: Jean Pihet <jean.pihet@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1406325766-8085-1-git-send-email-msalter@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-30 12:37:55 -03:00
Sukadev Bhattiprolu
c94b93cbca perf powerpc: Include util/util.h and remove stringify macros
The stringify macros are defined in tools/perf/util/util.h and don't
need to be redfined specfiically for powerpc.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Link: http://lkml.kernel.org/r/20140724074718.GB18829@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-24 11:00:39 -03:00
Adrian Hunter
a6a69db4b6 perf tools: Move rdtsc() function
Move the rdtsc() function so it can be reusued.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1406035081-14301-24-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-23 11:48:11 -03:00
Adrian Hunter
0b43786081 perf tools: Allow TSC conversion on any arch
It is possible to record a perf.data file on one architecture and
process it on another.

Consequently, TSC conversion functions need to be moved out of the arch
directory.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1405332185-4050-40-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-17 12:59:00 -03:00
Jiri Olsa
84f5d36f48 perf tools: Move pr_* debug macros into debug object
Moving pr_* debug macros to have it with in same object as debug
variables, becase we will change them to use verbose variable in next
patch.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1405374411-29012-3-git-send-email-jolsa@kernel.org
[ Add missing debug.h include in python scripting glue and in the libdw unwind lib ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-17 12:58:39 -03:00
Alexander Yarygin
3be8e2a0a5 perf kvm: Add stat support on s390
On s390, the vmexit event has a tree-like structure: between
exit_event_begin and exit_event_end several other events may happen and
with each of them refining the previous ones.

This patch adds a decoder for such events to the generic code and also
the files <asm/kvm_perf.h> and kvm-stat.c for s390.

Commands 'perf kvm stat record', 'report' and 'live' are supported.

Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1404397747-20939-5-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-16 17:57:33 -03:00
Alexander Yarygin
54c801ff71 perf kvm: Add skip_event() for --duration option
Current code skips output of the x86 specific HLT event in order to
avoid flooding the output with enabled --duration option. The events to
be skipped should be architecture dependent, though.

Let's add an architecture specific array of events to be skipped and
introduce a skip_event() function checking against that array.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1404397747-20939-4-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-16 17:57:32 -03:00
Alexander Yarygin
9daa81239e perf kvm: Move arch specific code into arch/
Parts of a 'perf kvm stat' code make sense only for x86.

Let's move this code into the arch/x86/kvm-stat.c file and add
util/kvm-stat.h for generic structure definitions.

Add a global array 'kvm_reg_events_ops' for accessing the arch-specific
'kvm_events_ops' from generic code.

Since the several global arrays (i.e. 'kvm_events_tp') have been moved
to arch/*, we can not know their sizes and use them directly in
builtin-kvm.c. This patch fixes that problem by adding trimming NULL
element to each array and changing the behavior of their handlers in
generic code.

Reviewed-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1404397747-20939-3-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-16 17:57:32 -03:00
Alexander Yarygin
f8d9ccde2b perf tools: Allow to use cpuinfo on s390
This patch defines CPUINFO_PROC for s390 and implements get_cpuid().

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/87ioneo7qh.wl%yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-07 16:55:24 -03:00
Alexander Yarygin
da50ad6972 perf kvm: Introduce HAVE_KVM_STAT_SUPPORT flag
kvm stat support is currently conditional on i386/x86_64. Let's abstract
this into a HAVE_KVM_STAT_SUPPORT flag, so that other architectures can
support kvm stat as well.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1404395992-17095-2-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-07-07 16:55:23 -03:00
Sukadev Bhattiprolu
a60335ba32 perf tools powerpc: Adjust callchain based on DWARF debug info
When saving the callchain on Power, the kernel conservatively saves excess
entries in the callchain. A few of these entries are needed in some cases
but not others. We should use the DWARF debug information to determine
when the entries are  needed.

Eg: the value in the link register (LR) is needed only when it holds the
return address of a function. At other times it must be ignored.

If the unnecessary entries are not ignored, we end up with duplicate arcs
in the call-graphs.

Use the DWARF debug information to determine if any callchain entries
should be ignored when building call-graphs.

Callgraph before the patch:

    14.67%          2234  sprintft  libc-2.18.so       [.] __random
            |
            --- __random
               |
               |--61.12%-- __random
               |          |
               |          |--97.15%-- rand
               |          |          do_my_sprintf
               |          |          main
               |          |          generic_start_main.isra.0
               |          |          __libc_start_main
               |          |          0x0
               |          |
               |           --2.85%-- do_my_sprintf
               |                     main
               |                     generic_start_main.isra.0
               |                     __libc_start_main
               |                     0x0
               |
                --38.88%-- rand
                          |
                          |--94.01%-- rand
                          |          do_my_sprintf
                          |          main
                          |          generic_start_main.isra.0
                          |          __libc_start_main
                          |          0x0
                          |
                           --5.99%-- do_my_sprintf
                                     main
                                     generic_start_main.isra.0
                                     __libc_start_main
                                     0x0

Callgraph after the patch:

    14.67%          2234  sprintft  libc-2.18.so       [.] __random
            |
            --- __random
               |
               |--95.93%-- rand
               |          do_my_sprintf
               |          main
               |          generic_start_main.isra.0
               |          __libc_start_main
               |          0x0
               |
                --4.07%-- do_my_sprintf
                          main
                          generic_start_main.isra.0
                          __libc_start_main
                          0x0

TODO:	For split-debug info objects like glibc, we can only determine
	the call-frame-address only when both .eh_frame and .debug_info
	sections are available. We should be able to determin the CFA
	even without the .eh_frame section.

Fix suggested by Anton Blanchard.

Thanks to valuable input on DWARF debug information from Ulrich Weigand.

Reported-by: Maynard Johnson <maynard@us.ibm.com>
Tested-by: Maynard Johnson <maynard@us.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/20140625154903.GA29607@us.ibm.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-06-27 11:14:51 +02:00
Jean Pihet
97eac381b1 perf tools: Add libdw DWARF post unwind support for ARM
Adding libdw DWARF post unwind support, which is part
of elfutils-devel/libdw-dev package from version 0.158.

The new code is contained in unwin-libdw.c object, and
implements unwind__get_entries unwind interface function.

Signed-off-by: Jean Pihet <jean.pihet@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1400229672-16104-4-git-send-email-jean.pihet@linaro.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-05-16 11:39:29 +02:00
Jean Pihet
90fa9deb32 perf tests: Add dwarf unwind test on ARM
Adding dwarf unwind test, that setups live machine data over
the perf test thread and does the remote unwind.

Need to use -fno-optimize-sibling-calls for test compilation,
otherwise 'krava_*' function calls are optimized into jumps
and omitted from the stack unwind.

So far it was enabled only for x86.

Signed-off-by: Jean Pihet <jean.pihet@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1400229672-16104-3-git-send-email-jean.pihet@linaro.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-05-16 11:39:18 +02:00
Jean Pihet
3418f9667e perf tests: Introduce perf_regs_load function on ARM
Introducing perf_regs_load function, which is going
to be used for dwarf unwind test in following patches.

It takes single argument as a pointer to the regs dump
buffer and populates it with current registers values.

Signed-off-by: Jean Pihet <jean.pihet@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1400229672-16104-2-git-send-email-jean.pihet@linaro.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-05-16 11:39:05 +02:00
Jean Pihet
21a8b756b8 perf tools: Consolidate types.h for ARM and ARM64
Prevents a build breakage since commit d944c4eebc
'tools: Consolidate types.h'

Signed-off-by: Jean Pihet <jean.pihet@linaro.org>
Link: http://lkml.kernel.org/r/1400229672-16104-1-git-send-email-jean.pihet@linaro.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-05-16 11:38:57 +02:00
Borislav Petkov
d944c4eebc tools: Consolidate types.h
Combine all definitions into a common tools/include/linux/types.h and
kill the wild growth elsewhere. Move DECLARE_BITMAP to its proper
bitmap.h header.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Link: http://lkml.kernel.org/n/tip-azczs7qcv6h9xek9od10hiv2@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-05-01 21:22:39 +02:00
Ingo Molnar
3617660e4e Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf into perf/core
Pull perf/core improvements and fixes from Jiri Olsa:

  * Wire up perf_regs and unwind support for ARM64 (Jean Pihet)

  * Move u64_swap union to its single user's header, evsel.h (Borislav Petkov)

  * Fix for s390 to properly parse tracepoints plus test code (Alexander Yarygin)

  * Handle EINTR error for readn/writen (Namhyung Kim)

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-01 08:24:59 +02:00
Ingo Molnar
aeffe2abc8 Merge branch 'perf/urgent' into perf/core, to resolve conflict
Conflicts:
	tools/perf/arch/x86/tests/dwarf-unwind.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-05-01 08:24:39 +02:00
Jiri Olsa
9a12672816 perf tests x86: Fix stack map lookup in dwarf unwind test
Previous commit 'perf x86: Fix perf to use non-executable stack, again'
moved stack map into MAP__VARIABLE map type again. Fixing the dwarf
unwind test stack map lookup appropriately.

Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Link: http://lkml.kernel.org/n/tip-ttzyhbe4zls24z7ednkmhvxl@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-04-30 17:02:31 +02:00
Mathias Krause
6392b4ebdc perf x86: Fix perf to use non-executable stack, again
arch/x86/tests/regs_load.S is missing the linker note about the stack
requirements, therefore making the linker fall back to an executable
stack. As this object gets linked against the final perf binary, it'll
needlessly end up with an executable stack. Fix this by adding the
appropriate linker note.

Also add a global linker flag to prevent future regressions, as
suggested by Jiri. This way perf won't get an executable stack even if
we fail to add the .GNU-stack linker note to future assembler files.
Though, doing so might create regressions the other way around, when
(statically) linking against libraries needing an executable stack.
But, apparently, regressing in that direction is wanted as it is an
indicator of poor code quality -- or just missing linker notes.

Fixes: 3c8b06f981 ("perf tests x86: Introduce perf_regs_load function")

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1398617466-22749-1-git-send-email-minipli@googlemail.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
2014-04-30 17:02:30 +02:00