kernel/linux.git/tools/perf/util/parse-regs-options.c, branch v7.1

perf regs: Remove weak attributive archxxx_reg_mask() functions

2026-02-06T15:16:09+00:00

Currently, some architecture-specific perf-regs functions, such as arch__intr_reg_mask() and arch__user_reg_mask(), are defined with the __weak attribute. This approach ensures that only functions matching the architecture of the build/run host are compiled and executed, reducing build time and binary size. However, this __weak attribute restricts these functions to be called only on the same architecture, preventing cross-architecture functionality. For example, a perf.data file captured on x86 cannot be parsed on an ARM platform. To address this limitation, this patch removes the __weak attribute from these perf-regs functions. The architecture-specific code is moved from the arch/ directory to the util/perf-regs-arch/ directory. The appropriate architectural functions are then called based on the EM_HOST. No functional changes are intended. Suggested-by: Ian Rogers Reviewed-by: Ian Rogers Signed-off-by: Dapeng Mi Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Guo Ren Cc: Ingo Molnar Cc: James Clark Cc: John Garry Cc: Mike Leach Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Thomas Falcon Cc: Will Deacon Cc: Xudong Hao Cc: Zide Chen [ Fixed up somme fuzz with s390 and riscv Build files wrt removing perf_regs.o ] Signed-off-by: Arnaldo Carvalho de Melo

perf regs: Fix abort for "-I" or "--user-regs" options

2026-02-06T15:15:22+00:00

Fix an issue where the `perf` tool aborts unexpectedly when running the following command: ``` perf record -e cycles -I -- true Usage: perf record [] [] or: perf record [] -- [] -I, --intr-regs[=] sample selected machine registers on interrupt, use '-I?' to list register names ``` The usage of the `-I` or `--user-regs` options without specifying any registers should default to sampling all general-purpose registers. However, this currently causes an abnormal termination. The issue was introduced by commit 3d06db9bad1a ("perf regs: Refactor use of arch__sample_reg_masks() to perf_reg_name()"). This patch resolves the problem, ensuring that the `-I` or `--user-regs` options work as intended without causing an abort. Fixes: 3d06db9bad1ad8e6 ("perf regs: Refactor use of arch__sample_reg_masks() to perf_reg_name()") Reviewed-by: Ian Rogers Signed-off-by: Dapeng Mi Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Guo Ren Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: John Garry Cc: linux-arm-kernel@lists.infradead.org Cc: linux-csky@vger.kernel.org Cc: linux-riscv@lists.infradead.org Cc: Mike Leach Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Thomas Falcon Cc: Will Deacon Cc: Xudong Hao Cc: Zide Chen Signed-off-by: Arnaldo Carvalho de Melo

perf perf_regs: Accurately compute register names for CSKY

2026-01-26T21:31:16+00:00

CSKY needs the e_flags to determine the ABI level and know whether additional registers are encoded or not. Wire this up now that the e_flags for a thread can be determined. Signed-off-by: Ian Rogers Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Guo Ren Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Swapnil Sapkal Cc: Tianyou Li [ Conditionally define EF_CSKY_ABIMASK and EF_CSKY_ABIV2 for older distros ] Signed-off-by: Arnaldo Carvalho de Melo

perf regs: Refactor use of arch__sample_reg_masks() to perf_reg_name()

2026-01-23T19:58:39+00:00

arch__sample_reg_masks isn't supported on ARM(32), csky, loongarch, MIPS, RISC-V and s390. The table returned by the function just has the name of a register paired with the corresponding sample_regs_user mask value. For a given perf register we can compute the name with perf_reg_name and the mask is just 1 left-shifted by the perf register number. Change __parse_regs to use this method for finding registers rather than arch__sample_reg_masks, thereby adding __parse_regs support for ARM(32), csky, loongarch, MIPS, RISC-V and s390. As arch__sample_reg_masks is then unused, remove the now unneeded declarations. Signed-off-by: Ian Rogers Tested-by: Thomas Richter Cc: Aditya Bodkhe Cc: Adrian Hunter Cc: Albert Ou Cc: Alexandre Ghiti Cc: Andi Kleen Cc: Athira Rajeev Cc: Chun-Tse Shao Cc: Dapeng Mi Cc: Dmitriy Vyukov Cc: Dr. David Alan Gilbert Cc: Guo Ren Cc: Haibo Xu Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Krzysztof Łopatowski Cc: Leo Yan Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Sergei Trofimovich Cc: Shimin Guo Cc: Stephen Brennan Cc: Thomas Falcon Cc: Will Deacon Signed-off-by: Arnaldo Carvalho de Melo

perf parse-regs: Introduce a weak function arch__sample_reg_masks()

2024-02-15T21:48:36+00:00

Every architecture can provide a register list for sampling. If an architecture doesn't support register sampling, it won't define the data structure 'sample_reg_masks'. Consequently, any code using this structure must be protected by the macro 'HAVE_PERF_REGS_SUPPORT'. This patch defines a weak function, arch__sample_reg_masks(), which will be replaced by an architecture-defined function for returning the architecture's register list. With this refactoring, the function always exists, the condition checking for 'HAVE_PERF_REGS_SUPPORT' is not needed anymore, so remove it. Signed-off-by: Leo Yan Reviewed-by: Ian Rogers Cc: James Clark Cc: Palmer Dabbelt Cc: Albert Ou Cc: Huacai Chen Cc: Guo Ren Cc: Will Deacon Cc: Mike Leach Cc: Kan Liang Cc: Ming Wang Cc: John Garry Cc: Paul Walmsley Cc: linux-csky@vger.kernel.org Cc: linux-riscv@lists.infradead.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240214113947.240957-4-leo.yan@linux.dev

perf record: Fix memory leak when using '--user-regs=?' to list registers

2020-12-17T17:36:16+00:00

When using 'perf record's option '-I' or '--user-regs=' along with argument '?' to list available register names, memory of variable 'os' allocated by strdup() needs to be released before __parse_regs() returns, otherwise memory leak will occur. Fixes: bcc84ec65ad1 ("perf record: Add ability to name registers to record") Signed-off-by: Zheng Zengkai Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Li Bin Cc: Mark Rutland Cc: Namhyung Kim Link: https://lore.kernel.org/r/20200703093344.189450-1-zhengzengkai@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Avoid 'sample_reg_masks' being const + weak

2019-10-10T12:29:33+00:00

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: https://github.com/llvm/llvm-project/commit/f49573d1eedcf1e44893d5a062ac1b72c8419646 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 Reviewed-by: Nick Desaulniers Acked-by: Jiri Olsa Cc: Albert Ou Cc: Alexander Shishkin Cc: Alexey Budankov Cc: Andi Kleen Cc: clang-built-linux@googlegroups.com Cc: Guo Ren Cc: Kan Liang Cc: linux-riscv@lists.infradead.org Cc: Mao Han Cc: Mark Rutland Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lore.kernel.org/lkml/20191001003623.255186-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add missing headers, mostly stdlib.h

2019-07-09T13:13:22+00:00

Part of the erosion of util/util.h, that will lose its include stdlib.h, we need to add it to places where it is needed but was getting it indirectly. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-1imnqezw99ahc07fjeb51qby@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf parse-regs: Add generic support for arch__intr/user_reg_mask()

2019-05-16T17:17:12+00:00

There may be different register mask for use with intr or user on some platforms, e.g. Icelake. Add weak functions arch__intr_reg_mask() and arch__user_reg_mask() to return intr and user register mask respectively. Check mask before printing or comparing the register name. Generic code always return PERF_REGS_MASK. No functional change. Suggested-by: Arnaldo Carvalho de Melo Signed-off-by: Kan Liang Tested-by: Ravi Bangoria Cc: Andi Kleen Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1557865174-56264-2-git-send-email-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf parse-regs: Split parse_regs

2019-05-15T19:36:49+00:00

The available registers for --int-regs and --user-regs may be different, e.g. XMM registers. Split parse_regs into two dedicated functions for --int-regs and --user-regs respectively. Modify the warning message. "--user-regs=?" should be applied to show the available registers for --user-regs. Signed-off-by: Kan Liang Tested-by: Ravi Bangoria Cc: Andi Kleen Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1557865174-56264-1-git-send-email-kan.liang@linux.intel.com [ Changed docs as suggested by Ravi and agreed by Kan ] Signed-off-by: Arnaldo Carvalho de Melo