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fa7095c5c3
Commit Fixes:b9f6fbb3b2("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'") intended to add a 'best effort' DWARF unwind that improved the frame pointer stack in most scenarios. It's expected that the unwind will fail sometimes, but this shouldn't be reported as an error. It only works when the return address can be determined from the contents of the link register alone. Fix the error shown when the unwinder requires extra registers by adding a new flag that suppresses error messages. This flag is not set in the normal --call-graph=dwarf unwind mode so that behavior is not changed. Fixes:b9f6fbb3b2("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'") Reported-by: John Garry <john.garry@huawei.com> Signed-off-by: James Clark <james.clark@arm.com> Tested-by: John Garry <john.garry@huawei.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexandre Truong <alexandre.truong@arm.com> Cc: German Gomez <german.gomez@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/r/20220406145651.1392529-1-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
91 lines
2.2 KiB
C
91 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "unwind.h"
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#include "dso.h"
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#include "map.h"
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#include "thread.h"
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#include "session.h"
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#include "debug.h"
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#include "env.h"
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#include "callchain.h"
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struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
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struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
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struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
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static void unwind__register_ops(struct maps *maps, struct unwind_libunwind_ops *ops)
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{
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maps->unwind_libunwind_ops = ops;
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}
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int unwind__prepare_access(struct maps *maps, struct map *map, bool *initialized)
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{
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const char *arch;
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enum dso_type dso_type;
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struct unwind_libunwind_ops *ops = local_unwind_libunwind_ops;
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int err;
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if (!dwarf_callchain_users)
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return 0;
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if (maps->addr_space) {
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pr_debug("unwind: thread map already set, dso=%s\n",
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map->dso->name);
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if (initialized)
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*initialized = true;
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return 0;
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}
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/* env->arch is NULL for live-mode (i.e. perf top) */
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if (!maps->machine->env || !maps->machine->env->arch)
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goto out_register;
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dso_type = dso__type(map->dso, maps->machine);
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if (dso_type == DSO__TYPE_UNKNOWN)
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return 0;
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arch = perf_env__arch(maps->machine->env);
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if (!strcmp(arch, "x86")) {
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if (dso_type != DSO__TYPE_64BIT)
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ops = x86_32_unwind_libunwind_ops;
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} else if (!strcmp(arch, "arm64") || !strcmp(arch, "arm")) {
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if (dso_type == DSO__TYPE_64BIT)
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ops = arm64_unwind_libunwind_ops;
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}
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if (!ops) {
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pr_err("unwind: target platform=%s is not supported\n", arch);
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return 0;
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}
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out_register:
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unwind__register_ops(maps, ops);
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err = maps->unwind_libunwind_ops->prepare_access(maps);
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if (initialized)
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*initialized = err ? false : true;
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return err;
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}
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void unwind__flush_access(struct maps *maps)
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{
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if (maps->unwind_libunwind_ops)
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maps->unwind_libunwind_ops->flush_access(maps);
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}
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void unwind__finish_access(struct maps *maps)
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{
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if (maps->unwind_libunwind_ops)
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maps->unwind_libunwind_ops->finish_access(maps);
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}
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int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
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struct thread *thread,
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struct perf_sample *data, int max_stack,
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bool best_effort)
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{
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if (thread->maps->unwind_libunwind_ops)
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return thread->maps->unwind_libunwind_ops->get_entries(cb, arg, thread, data,
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max_stack, best_effort);
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return 0;
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}
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