6 Commits

Author SHA1 Message Date
Ian Rogers
42466b9f29 perf tools: Avoid 'sample_reg_masks' being const + weak
Being const + weak breaks with some compilers that constant-propagate
from the weak symbol. This behavior is outside of the specification, but
in LLVM is chosen to match GCC's behavior.

LLVM's implementation was set in this patch:

  f49573d1ee

A const + weak symbol is set to be weak_odr:

  https://llvm.org/docs/LangRef.html

ODR is one definition rule, and given there is one constant definition
constant-propagation is possible. It is possible to get this code to
miscompile with LLVM when applying link time optimization. As compilers
become more aggressive, this is likely to break in more instances.

Move the definition of sample_reg_masks to the conditional part of
perf_regs.h and guard usage with HAVE_PERF_REGS_SUPPORT. This avoids the
weak symbol.

Fix an issue when HAVE_PERF_REGS_SUPPORT isn't defined from patch v1.
In v3, add perf_regs.c for architectures that HAVE_PERF_REGS_SUPPORT but
don't declare sample_regs_masks.

Further notes:

Jiri asked:

  "Is this just a precaution or you actualy saw some breakage?"

Ian answered:

  "We saw a breakage with clang with thinlto enabled for linking. Our
   compiler team had recently seen, and were surprised by, a similar issue
   and were able to dig out the weak ODR issue."

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: clang-built-linux@googlegroups.com
Cc: Guo Ren <guoren@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: linux-riscv@lists.infradead.org
Cc: Mao Han <han_mao@c-sky.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20191001003623.255186-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-10-10 09:29:33 -03:00
Jiri Olsa
5ff328836d perf tools: Rename build libperf to perf
Rename build libperf to perf, because it's used to build perf.

The libperf build object name will be used for libperf library.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190213123246.4015-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-02-14 15:18:08 -03:00
Mathieu Poirier
a818c563ae perf tools: Add coresight etm PMU record capabilities
Coresight ETMs are IP blocks used to perform HW assisted tracing on a
CPU core.  This patch introduce the required auxiliary API functions
allowing the perf core to interact with a tracer.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1474041004-13956-4-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-09-22 12:19:40 -03:00
Mathieu Poirier
7e21b0d579 perf tools: Make coresight PMU listable
Adding the required mechanic allowing 'perf list pmu' to discover
coresight ETM/PTM tracers.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1474041004-13956-3-git-send-email-mathieu.poirier@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-09-22 12:19:35 -03:00
He Kuang
9d8e14d306 perf unwind: Separate local/remote libunwind config
CONFIG_LIBUNWIND/NO_LIBUNWIND are changed to CONFIG_LOCAL_LIBUNWIND/
NO_LOCAL_LIBUNWIND for retaining local unwind features. The new
CONFIG_LIBUNWIND stands for either local or remote or both unwind are
supported, and NO_LIBUNWIND means that neither local nor remote unwind
is supported.

LIBUNWIND_LIBS is eliminated in LDFLAGS if local libunwind is not
supported.

Signed-off-by: He Kuang <hekuang@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1464924803-22214-7-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-06-07 12:08:52 -03:00
Jiri Olsa
f6ff0e6d7b perf build: Add arch arm objects building
Move the arm arch objects building under build framework to be included
in the libperf build object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-7bxhmeh4bjabqsmxu4gl6p0b@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-02-12 13:13:01 -03:00