From nobody Thu Apr 9 21:51:26 2026 Received: from mail-dl1-f74.google.com (mail-dl1-f74.google.com [74.125.82.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66D573624C3 for ; Thu, 5 Mar 2026 22:19:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772749183; cv=none; b=DSvVJe9cXUsSF3CvquWERui+ZCjRLb98VOq8+guosQJisV3m6jkeqvXiOKg6XTwRY3/XZBaQnobEjeH9sFb6AZ74TnRvQ0jvR7hadVvjEVpaVij3FDHIJ52Acd6Km6WKPZ4BY8dshQ52QssM2qQYkKSBfLhoba6q00JtiWoJNwM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772749183; c=relaxed/simple; bh=JyAAez58X4D2TUjK+ofESbbInKX6QnXCuE///zO5y+s=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=mKM/Hrc6IWvwl1pqezrg2AnP8Km0KdU9YF4e+SeemQkElvI4ARiA0wVw9MjHKJgLTyfg+FcQlkXividDSKeMwlocWvC1qnQ0L0Ni0CtH+GRhQU8rkxU2dyt720M2luD2rhelbijr0uUTbAcMoFc2qIl7l87m2h8hIS3shOuPbPE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Jm4zsSJE; arc=none smtp.client-ip=74.125.82.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Jm4zsSJE" Received: by mail-dl1-f74.google.com with SMTP id a92af1059eb24-128ba70cc99so1962741c88.0 for ; Thu, 05 Mar 2026 14:19:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772749181; x=1773353981; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=V/5FsEHMS6n6PE3kEHPdT1dcIRmDeXw08dhLTo8bgaQ=; b=Jm4zsSJEAqnCMPUzkr0mwjTkUKqZty93EDZOJFJiRnzl0LDUPFLtzcNZJBtXwjFlf/ TGBZhbYiPm8Ah8qKTXgPKQuExihjfz3KstOPuymddOqgAX0YsqVC1neZsIKsH40mVt2L kRIFMP4D5xmbOKjLcuV2qnJA7brt6bLjLDVKi30F41xAFFOUkcr7GYMZtIgloksQk2TR Ts07pOvIvJFAEwQLG0Efguzwfh1B1NsnBlAerdhHIglhk//AvT64kEk9g8+uV7vNg+72 iQCLQ/rXtwziOrdUvOVWu1aAy4xQfsYslB4oAHfaYC7D4fa1yPAQ1bUBAbsi7yX4l0VP EJCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772749181; x=1773353981; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=V/5FsEHMS6n6PE3kEHPdT1dcIRmDeXw08dhLTo8bgaQ=; b=pHfTl4XZ5pHGrSF18fOL8KCsFkzxxx+2N5SBzFghUWvGvw4uruemdDDbhvaeuEQWaM ScQup8XKX+j+Svj3g91gz5QmxnhPDeumNXHj3zooTII4ebNfTsRYU4hdEJ3lBnYEIk+f LTmz7lFxlpmp4lTU50ioUYj8iVfZYh6ECt30CIdkoakUTBTUzTXoHSGGGXkfjK5PmRsP i/mH6Rcf/USB/Gx97JWwFuE/a3AhTeItkwW37R6/1Xj15vXAhPVqCnTH7xnKrXzuvcZP eD/PPr3zDt/+jSlnuvzI0rC7fAa9/Vox6pN2dp5noIeX4dwPb0/G9OI4UQYT5sEklN7M qwTQ== X-Forwarded-Encrypted: i=1; AJvYcCUE6ytJZTjsNcrFdB3A95Le9D/TRInriJHjz6HJC9XPZhiMUl505B1bqLaoHYl91b9OfkO99c8A0s0JpN4=@vger.kernel.org X-Gm-Message-State: AOJu0YyNsACdDq43t9wDULgBPnQPaT819lNWw0cjTyEAdajTfup1Qc8+ I5XRgHu8bM20YVUZtngTG+JDjAYXYFH9bHKGWTN/OfOZjbjd2MZ5wfcd5+Er9vH1BuVZ56czwEH T43oxOCjbvw== X-Received: from dlbvv5.prod.google.com ([2002:a05:7022:5f05:b0:128:bb47:9b7]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:518:b0:127:5c54:a124 with SMTP id a92af1059eb24-128c2e8efdbmr5925c88.31.1772749181224; Thu, 05 Mar 2026 14:19:41 -0800 (PST) Date: Thu, 5 Mar 2026 14:19:20 -0800 In-Reply-To: <20260305221927.3237145-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260305221927.3237145-1-irogers@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260305221927.3237145-2-irogers@google.com> Subject: [PATCH v2 1/8] perf unwind: Refactor get_entries to allow dynamic libdw/libunwind selection From: Ian Rogers To: irogers@google.com Cc: 9erthalion6@gmail.com, acme@kernel.org, adrian.hunter@intel.com, alex@ghiti.fr, alexander.shishkin@linux.intel.com, andrew.jones@oss.qualcomm.com, aou@eecs.berkeley.edu, atrajeev@linux.ibm.com, blakejones@google.com, ctshao@google.com, dapeng1.mi@linux.intel.com, howardchu95@gmail.com, james.clark@linaro.org, john.g.garry@oracle.com, jolsa@kernel.org, leo.yan@linux.dev, libunwind-devel@nongnu.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-riscv@lists.infradead.org, mingo@redhat.com, namhyung@kernel.org, palmer@dabbelt.com, peterz@infradead.org, pjw@kernel.org, shimin.guo@skydio.com, tglozar@redhat.com, tmricht@linux.ibm.com, will@kernel.org, yuzhuo@google.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, both libdw and libunwind define 'unwind__get_entries'. This causes a duplicate symbol build failure when both are compiled into perf. This commit refactors the DWARF unwind post-processing to be configurable at runtime via the .perfconfig file option 'unwind.style', or using the argument '--unwind-style' in the commands 'perf report', 'perf script' and 'perf inject', in a similar manner to the addr2line or the disassembler style. The file 'tools/perf/util/unwind.c' adds the top-level dispatch function 'unwind__get_entries'. The backend implementations are renamed to 'libdw__get_entries' and 'libunwind__get_entries'. Both are attempted as fallbacks if not configured, or if the primary backend fails. Fixes: 2e9191573a69 ("perf build: Remove NO_LIBDW_DWARF_UNWIND option") Signed-off-by: Ian Rogers --- tools/perf/builtin-inject.c | 4 ++ tools/perf/builtin-report.c | 4 ++ tools/perf/builtin-script.c | 4 ++ tools/perf/util/Build | 1 + tools/perf/util/symbol_conf.h | 15 +++++ tools/perf/util/unwind-libdw.c | 2 +- tools/perf/util/unwind-libunwind.c | 2 +- tools/perf/util/unwind.c | 102 +++++++++++++++++++++++++++++ tools/perf/util/unwind.h | 40 +++++------ 9 files changed, 149 insertions(+), 25 deletions(-) create mode 100644 tools/perf/util/unwind.c diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c index 5b29f4296861..9ad681b3c0dc 100644 --- a/tools/perf/builtin-inject.c +++ b/tools/perf/builtin-inject.c @@ -26,6 +26,7 @@ #include "util/synthetic-events.h" #include "util/thread.h" #include "util/namespaces.h" +#include "util/unwind.h" #include "util/util.h" #include "util/tsc.h" =20 @@ -2539,6 +2540,9 @@ int cmd_inject(int argc, const char **argv) OPT_STRING(0, "guestmount", &symbol_conf.guestmount, "directory", "guest mount directory under which every guest os" " instance has a subdir"), + OPT_CALLBACK(0, "unwind-style", NULL, "unwind style", + "unwind styles (libdw,libunwind)", + unwind__option), OPT_BOOLEAN(0, "convert-callchain", &inject.convert_callchain, "Generate callchains using DWARF and drop register/stack data"), OPT_END() diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 3b81f4b3dc49..ae20c0679990 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -48,6 +48,7 @@ #include "util/time-utils.h" #include "util/auxtrace.h" #include "util/units.h" +#include "util/unwind.h" #include "util/util.h" // perf_tip() #include "ui/ui.h" #include "ui/progress.h" @@ -1455,6 +1456,9 @@ int cmd_report(int argc, const char **argv) OPT_CALLBACK(0, "addr2line-style", NULL, "addr2line style", "addr2line styles (libdw,llvm,libbfd,addr2line)", report_parse_addr2line_config), + OPT_CALLBACK(0, "unwind-style", NULL, "unwind style", + "unwind styles (libdw,libunwind)", + unwind__option), OPT_BOOLEAN(0, "demangle", &symbol_conf.demangle, "Symbol demangling. Enabled by default, use --no-demangle to disable= ."), OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel, diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index 9f8b0fd27a0a..b6c7c164d02d 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -63,6 +63,7 @@ #include #include "util/dlfilter.h" #include "util/record.h" +#include "util/unwind.h" #include "util/util.h" #include "util/cgroup.h" #include "util/annotate.h" @@ -4164,6 +4165,9 @@ int cmd_script(int argc, const char **argv) "Enable symbol demangling"), OPT_BOOLEAN(0, "demangle-kernel", &symbol_conf.demangle_kernel, "Enable kernel symbol demangling"), + OPT_CALLBACK(0, "unwind-style", NULL, "unwind style", + "unwind styles (libdw,libunwind)", + unwind__option), OPT_STRING(0, "addr2line", &symbol_conf.addr2line_path, "path", "addr2line binary to use for line numbers"), OPT_STRING(0, "time", &script.time_str, "str", diff --git a/tools/perf/util/Build b/tools/perf/util/Build index bcccad7487a9..6190a8f5b0fa 100644 --- a/tools/perf/util/Build +++ b/tools/perf/util/Build @@ -218,6 +218,7 @@ ifndef CONFIG_SETNS perf-util-y +=3D setns.o endif =20 +perf-util-y +=3D unwind.o perf-util-$(CONFIG_LIBDW) +=3D probe-finder.o perf-util-$(CONFIG_LIBDW) +=3D dwarf-aux.o perf-util-$(CONFIG_LIBDW) +=3D dwarf-regs.o diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h index 71bb17372a6c..25d92bbbfee7 100644 --- a/tools/perf/util/symbol_conf.h +++ b/tools/perf/util/symbol_conf.h @@ -9,6 +9,19 @@ struct strlist; struct intlist; =20 +enum unwind_style { + + UNWIND_STYLE_UNKNOWN =3D 0, + + UNWIND_STYLE_LIBDW, + + UNWIND_STYLE_LIBUNWIND, + +}; + +#define MAX_UNWIND_STYLE (UNWIND_STYLE_LIBUNWIND + 1) + + enum a2l_style { A2L_STYLE_UNKNOWN =3D 0, A2L_STYLE_LIBDW, @@ -80,6 +93,7 @@ struct symbol_conf { *bt_stop_list_str; const char *addr2line_path; enum a2l_style addr2line_style[MAX_A2L_STYLE]; + enum unwind_style unwind_style[MAX_UNWIND_STYLE]; unsigned long time_quantum; struct strlist *dso_list, *comm_list, @@ -103,3 +117,4 @@ struct symbol_conf { extern struct symbol_conf symbol_conf; =20 #endif // __PERF_SYMBOL_CONF + diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c index 05e8e68bd49c..d8a5b7d54192 100644 --- a/tools/perf/util/unwind-libdw.c +++ b/tools/perf/util/unwind-libdw.c @@ -339,7 +339,7 @@ frame_callback(Dwfl_Frame *state, void *arg) DWARF_CB_ABORT : DWARF_CB_OK; } =20 -int unwind__get_entries(unwind_entry_cb_t cb, void *arg, +int libdw__get_entries(unwind_entry_cb_t cb, void *arg, struct thread *thread, struct perf_sample *data, int max_stack, diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-li= bunwind.c index cb8be6acfb6f..a0016b897dae 100644 --- a/tools/perf/util/unwind-libunwind.c +++ b/tools/perf/util/unwind-libunwind.c @@ -79,7 +79,7 @@ void unwind__finish_access(struct maps *maps) ops->finish_access(maps); } =20 -int unwind__get_entries(unwind_entry_cb_t cb, void *arg, +int libunwind__get_entries(unwind_entry_cb_t cb, void *arg, struct thread *thread, struct perf_sample *data, int max_stack, bool best_effort) diff --git a/tools/perf/util/unwind.c b/tools/perf/util/unwind.c new file mode 100644 index 000000000000..9ae7d5ad246d --- /dev/null +++ b/tools/perf/util/unwind.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "debug.h" +#include "symbol_conf.h" +#include "unwind.h" +#include +#include +#include + +int unwind__get_entries(unwind_entry_cb_t cb __maybe_unused, void *arg __m= aybe_unused, + struct thread *thread __maybe_unused, + struct perf_sample *data __maybe_unused, + int max_stack __maybe_unused, + bool best_effort __maybe_unused) +{ + int ret =3D 0; + +#if defined(HAVE_LIBDW_SUPPORT) || defined(HAVE_LIBUNWIND_SUPPORT) + if (symbol_conf.unwind_style[0] =3D=3D UNWIND_STYLE_UNKNOWN) { + int i =3D 0; +#ifdef HAVE_LIBDW_SUPPORT + symbol_conf.unwind_style[i++] =3D UNWIND_STYLE_LIBDW; +#endif +#ifdef HAVE_LIBUNWIND_SUPPORT + symbol_conf.unwind_style[i++] =3D UNWIND_STYLE_LIBUNWIND; +#endif + } +#endif //defined(HAVE_LIBDW_SUPPORT) || defined(HAVE_LIBUNWIND_SUPPORT) + + for (size_t i =3D 0; i < ARRAY_SIZE(symbol_conf.unwind_style); i++) { + switch (symbol_conf.unwind_style[i]) { + case UNWIND_STYLE_LIBDW: +#ifdef HAVE_LIBDW_SUPPORT + ret =3D libdw__get_entries(cb, arg, thread, data, max_stack, best_effor= t); +#endif + break; + case UNWIND_STYLE_LIBUNWIND: +#ifdef HAVE_LIBUNWIND_SUPPORT + ret =3D libunwind__get_entries(cb, arg, thread, data, max_stack, best_e= ffort); +#endif + break; + case UNWIND_STYLE_UNKNOWN: + default: +#if !defined(HAVE_LIBDW_SUPPORT) && !defined(HAVE_LIBUNWIND_SUPPORT) + pr_warning_once( + "Error: dwarf unwinding not supported, build perf with libdw or libunw= ind.\n"); +#endif + ret =3D -1; + break; + } + if (ret =3D=3D 0) + break; + } + return ret; +} + +int unwind__configure(const char *var, const char *value, void *cb __maybe= _unused) +{ + static const char * const unwind_style_names[] =3D { + [UNWIND_STYLE_LIBDW] =3D "libdw", + [UNWIND_STYLE_LIBUNWIND] =3D "libunwind", + NULL + }; + char *s, *p, *saveptr; + size_t i =3D 0; + + if (strcmp(var, "unwind.style")) + return 0; + + if (!value) + return -1; + + s =3D strdup(value); + if (!s) + return -1; + + p =3D strtok_r(s, ",", &saveptr); + while (p && i < ARRAY_SIZE(symbol_conf.unwind_style)) { + bool found =3D false; + char *q =3D strim(p); + + for (size_t j =3D UNWIND_STYLE_LIBDW; j < MAX_UNWIND_STYLE; j++) { + if (!strcasecmp(q, unwind_style_names[j])) { + symbol_conf.unwind_style[i++] =3D j; + found =3D true; + break; + } + } + if (!found) + pr_warning("Unknown unwind style: %s\n", q); + p =3D strtok_r(NULL, ",", &saveptr); + } + + free(s); + return 0; +} + +int unwind__option(const struct option *opt __maybe_unused, + const char *arg, + int unset __maybe_unused) +{ + return unwind__configure("unwind.style", arg, NULL); +} diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h index 9f7164c6d9aa..581d042e170a 100644 --- a/tools/perf/util/unwind.h +++ b/tools/perf/util/unwind.h @@ -7,6 +7,7 @@ #include "util/map_symbol.h" =20 struct maps; +struct option; struct perf_sample; struct thread; =20 @@ -26,7 +27,9 @@ struct unwind_libunwind_ops { struct perf_sample *data, int max_stack, bool best_effort); }; =20 -#ifdef HAVE_DWARF_UNWIND_SUPPORT +int unwind__configure(const char *var, const char *value, void *cb); +int unwind__option(const struct option *opt, const char *arg, int unset); + /* * When best_effort is set, don't report errors and fail silently. This co= uld * be expanded in the future to be more permissive about things other than @@ -36,8 +39,20 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, struct thread *thread, struct perf_sample *data, int max_stack, bool best_effort); -/* libunwind specific */ + +#ifdef HAVE_LIBDW_SUPPORT +int libdw__get_entries(unwind_entry_cb_t cb, void *arg, + struct thread *thread, + struct perf_sample *data, int max_stack, + bool best_effort); +#endif + #ifdef HAVE_LIBUNWIND_SUPPORT +/* libunwind specific */ +int libunwind__get_entries(unwind_entry_cb_t cb, void *arg, + struct thread *thread, + struct perf_sample *data, int max_stack, + bool best_effort); #ifndef LIBUNWIND__ARCH_REG_ID #define LIBUNWIND__ARCH_REG_ID(regnum) libunwind__arch_reg_id(regnum) #endif @@ -57,26 +72,5 @@ static inline int unwind__prepare_access(struct maps *ma= ps __maybe_unused, static inline void unwind__flush_access(struct maps *maps __maybe_unused) = {} static inline void unwind__finish_access(struct maps *maps __maybe_unused)= {} #endif -#else -static inline int -unwind__get_entries(unwind_entry_cb_t cb __maybe_unused, - void *arg __maybe_unused, - struct thread *thread __maybe_unused, - struct perf_sample *data __maybe_unused, - int max_stack __maybe_unused, - bool best_effort __maybe_unused) -{ - return 0; -} - -static inline int unwind__prepare_access(struct maps *maps __maybe_unused, - struct map *map __maybe_unused, - bool *initialized __maybe_unused) -{ - return 0; -} =20 -static inline void unwind__flush_access(struct maps *maps __maybe_unused) = {} -static inline void unwind__finish_access(struct maps *maps __maybe_unused)= {} -#endif /* HAVE_DWARF_UNWIND_SUPPORT */ #endif /* __UNWIND_H */ --=20 2.53.0.473.g4a7958ca14-goog