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4248ae6e79
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: 2e9191573a ("perf build: Remove NO_LIBDW_DWARF_UNWIND option")
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andrew Jones <andrew.jones@oss.qualcomm.com>
Cc: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: libunwind-devel@nongnu.org
Cc: Li Guan <guanli.oerv@isrc.iscas.ac.cn>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shimin Guo <shimin.guo@skydio.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Will Deacon <will@kernel.org>
[ Don't mix declarations and code, move 'entries' variable to the start of scope ]
[ Use pr_warning_once() instead of pr_err() in stubs for get_entries(), suggested by a local sashiko instance ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
105 lines
2.5 KiB
C
105 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "debug.h"
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#include "symbol_conf.h"
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#include "unwind.h"
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#include <linux/string.h>
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#include <string.h>
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#include <stdlib.h>
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int unwind__get_entries(unwind_entry_cb_t cb __maybe_unused, void *arg __maybe_unused,
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struct thread *thread __maybe_unused,
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struct perf_sample *data __maybe_unused,
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int max_stack __maybe_unused,
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bool best_effort __maybe_unused)
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{
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int ret = 0;
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#if defined(HAVE_LIBDW_SUPPORT) || defined(HAVE_LIBUNWIND_SUPPORT)
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if (symbol_conf.unwind_style[0] == UNWIND_STYLE_UNKNOWN) {
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int i = 0;
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#ifdef HAVE_LIBDW_SUPPORT
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symbol_conf.unwind_style[i++] = UNWIND_STYLE_LIBDW;
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#endif
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#ifdef HAVE_LIBUNWIND_SUPPORT
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symbol_conf.unwind_style[i++] = UNWIND_STYLE_LIBUNWIND;
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#endif
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}
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#endif //defined(HAVE_LIBDW_SUPPORT) || defined(HAVE_LIBUNWIND_SUPPORT)
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for (size_t i = 0; i < ARRAY_SIZE(symbol_conf.unwind_style); i++) {
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switch (symbol_conf.unwind_style[i]) {
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case UNWIND_STYLE_LIBDW:
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ret = libdw__get_entries(cb, arg, thread, data, max_stack, best_effort);
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break;
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case UNWIND_STYLE_LIBUNWIND:
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ret = libunwind__get_entries(cb, arg, thread, data, max_stack, best_effort);
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break;
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case UNWIND_STYLE_UNKNOWN:
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default:
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#if !defined(HAVE_LIBDW_SUPPORT) && !defined(HAVE_LIBUNWIND_SUPPORT)
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pr_warning_once(
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"Error: dwarf unwinding not supported, build perf with libdw or libunwind.\n");
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#endif
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ret = 0;
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break;
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}
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if (ret > 0) {
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ret = 0;
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break;
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}
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if (ret < 0)
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break;
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}
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return ret;
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}
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int unwind__configure(const char *var, const char *value, void *cb __maybe_unused)
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{
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static const char * const unwind_style_names[] = {
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[UNWIND_STYLE_LIBDW] = "libdw",
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[UNWIND_STYLE_LIBUNWIND] = "libunwind",
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NULL
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};
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char *s, *p, *saveptr;
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size_t i = 0;
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if (strcmp(var, "unwind.style"))
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return 0;
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if (!value)
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return -1;
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s = strdup(value);
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if (!s)
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return -1;
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memset(symbol_conf.unwind_style, 0, sizeof(symbol_conf.unwind_style));
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p = strtok_r(s, ",", &saveptr);
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while (p && i < ARRAY_SIZE(symbol_conf.unwind_style)) {
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bool found = false;
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char *q = strim(p);
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for (size_t j = UNWIND_STYLE_LIBDW; j < MAX_UNWIND_STYLE; j++) {
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if (!strcasecmp(q, unwind_style_names[j])) {
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symbol_conf.unwind_style[i++] = j;
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found = true;
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break;
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}
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}
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if (!found)
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pr_warning("Unknown unwind style: %s\n", q);
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p = strtok_r(NULL, ",", &saveptr);
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}
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free(s);
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return 0;
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}
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int unwind__option(const struct option *opt __maybe_unused,
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const char *arg,
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int unset __maybe_unused)
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{
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return unwind__configure("unwind.style", arg, NULL);
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}
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