perf tools: Make it possible to see perf's kernel and module memory mappings

Dump kmaps if using 'perf --debug kmaps' or verbose > 2 (e.g. -vvv) for
tools 'perf script' and 'perf report' if there is no browser.

Example:

  $ perf --debug kmaps script 2>&1 >/dev/null | grep kvm.intel
  build id event received for /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko: 0691d75e10e72ebbbd45a44c59f6d00a5604badf [20]
  Map: 0-3a3 4f5d8 [kvm_intel].modinfo
  Map: 0-5240 5f280 [kvm_intel]__versions
  Map: 0-30 64 [kvm_intel].note.Linux
  Map: 0-14 644c0 [kvm_intel].orc_header
  Map: 0-5297 43680 [kvm_intel].rodata
  Map: 0-5bee 3b837 [kvm_intel].text.unlikely
  Map: 0-7e0 41430 [kvm_intel].noinstr.text
  Map: 0-2080 713c0 [kvm_intel].bss
  Map: 0-26 705c8 [kvm_intel].data..read_mostly
  Map: 0-5888 6a4c0 [kvm_intel].data
  Map: 0-22 70220 [kvm_intel].data.once
  Map: 0-40 705f0 [kvm_intel].data..percpu
  Map: 0-1685 41d20 [kvm_intel].init.text
  Map: 0-4b8 6fd60 [kvm_intel].init.data
  Map: 0-380 70248 [kvm_intel]__dyndbg
  Map: 0-8 70218 [kvm_intel].exit.data
  Map: 0-438 4f980 [kvm_intel]__param
  Map: 0-5f5 4ca0f [kvm_intel].rodata.str1.1
  Map: 0-3657 493b8 [kvm_intel].rodata.str1.8
  Map: 0-e0 70640 [kvm_intel].data..ro_after_init
  Map: 0-500 70ec0 [kvm_intel].gnu.linkonce.this_module
  Map: ffffffffc13a7000-ffffffffc1421000 a0 /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko

The example above shows how the module section mappings are all wrong
except for the main .text mapping at 0xffffffffc13a7000.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Like Xu <like.xu.linux@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240208085326.13432-2-adrian.hunter@intel.com

diff --git a/tools/perf/Documentation/perf.txt b/tools/perf/Documentation/perf.txt
index a7cf7bc2f9689dcdfea6cbe8daaaf01205e76be3..09f516f3fdfb051f639b09e5afb35fa53a894c88 100644 (file)
--- a/tools/perf/Documentation/perf.txt
+++ b/tools/perf/Documentation/perf.txt
@@ -63,6 +63,8 @@ OPTIONS
                              in browser mode
           perf-event-open  - Print perf_event_open() arguments and
                              return value
+          kmaps            - Print kernel and module maps (perf script
+                             and perf report without browser)
 
 --debug-file::
        Write debug output to a specified file.

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index ccb91fe6b8768c9d5a9fe170ed4d0b1f1470a003..8e16fa261e6f9950573954c42798371504224ec1 100644 (file)
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1766,6 +1766,8 @@ repeat:
        } else
                ret = 0;
 
+       if (!use_browser && (verbose > 2 || debug_kmaps))
+               perf_session__dump_kmaps(session);
 error:
        if (report.ptime_range) {
                itrace_synth_opts__clear_time_range(&itrace_synth_opts);

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index af63b7c37c8a52ec261fe7d8db17144e5181b2f1..24baa8284add9f7bc6f963f6fcdc5befa98e4e71 100644 (file)
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -4378,6 +4378,9 @@ script_found:
 
        flush_scripting();
 
+       if (verbose > 2 || debug_kmaps)
+               perf_session__dump_kmaps(session);
+
 out_delete:
        if (script.ptime_range) {
                itrace_synth_opts__clear_time_range(&itrace_synth_opts);

diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index e282b4ceb4d25fd560a972acb50689010bd01a85..c39ee0fcb8cf1d158f635b134dfd930d8d0ccca8 100644 (file)
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -33,6 +33,7 @@
 #endif
 
 int verbose;
+int debug_kmaps;
 int debug_peo_args;
 bool dump_trace = false, quiet = false;
 int debug_ordered_events;
@@ -229,6 +230,7 @@ static struct sublevel_option debug_opts[] = {
        { .name = "stderr",             .value_ptr = &redirect_to_stderr},
        { .name = "data-convert",       .value_ptr = &debug_data_convert },
        { .name = "perf-event-open",    .value_ptr = &debug_peo_args },
+       { .name = "kmaps",              .value_ptr = &debug_kmaps },
        { .name = NULL, }
 };
 
@@ -267,6 +269,7 @@ int perf_quiet_option(void)
        /* For debug variables that are used as bool types, set to 0. */
        redirect_to_stderr = 0;
        debug_peo_args = 0;
+       debug_kmaps = 0;
 
        return 0;
 }

diff --git a/tools/perf/util/debug.h b/tools/perf/util/debug.h
index de8870980d44abc3f4a52add52affbdaefe11448..35a7a5ae762e6f5be3da0265b6e542c5ec4a8969 100644 (file)
--- a/tools/perf/util/debug.h
+++ b/tools/perf/util/debug.h
@@ -9,6 +9,7 @@
 #include <linux/compiler.h>
 
 extern int verbose;
+extern int debug_kmaps;
 extern int debug_peo_args;
 extern bool quiet, dump_trace;
 extern int debug_ordered_events;

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 8761f51b5c7c88b938bd709ae9821e39045265b5..075c0f79b1b92d4c41f218adccd0c5c602556028 100644 (file)
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -181,6 +181,7 @@ int perf_bpf_filter__destroy(struct evsel *evsel __maybe_unused)
  * implementing 'verbose' and 'eprintf'.
  */
 int verbose;
+int debug_kmaps;
 int debug_peo_args;
 
 int eprintf(int level, int var, const char *fmt, ...);

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 199d3e8df31581c02245967d795847783556ee4c..06d0bd7fb45999740bd5c3462b17db2a555916c8 100644 (file)
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2720,6 +2720,17 @@ size_t perf_session__fprintf(struct perf_session *session, FILE *fp)
        return machine__fprintf(&session->machines.host, fp);
 }
 
+void perf_session__dump_kmaps(struct perf_session *session)
+{
+       int save_verbose = verbose;
+
+       fflush(stdout);
+       fprintf(stderr, "Kernel and module maps:\n");
+       verbose = 0; /* Suppress verbose to print a summary only */
+       maps__fprintf(machine__kernel_maps(&session->machines.host), stderr);
+       verbose = save_verbose;
+}
+
 struct evsel *perf_session__find_first_evtype(struct perf_session *session,
                                              unsigned int type)
 {

diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index ee3715e8563bfc6f86b814778214be052e0a703e..5064c6ec11e7317515fc9ae812ac37fc4e6567b9 100644 (file)
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -133,6 +133,8 @@ size_t perf_session__fprintf_dsos_buildid(struct perf_session *session, FILE *fp
 size_t perf_session__fprintf_nr_events(struct perf_session *session, FILE *fp,
                                       bool skip_empty);
 
+void perf_session__dump_kmaps(struct perf_session *session);
+
 struct evsel *perf_session__find_first_evtype(struct perf_session *session,
                                            unsigned int type);