Commit 0bdfbd04 authored by Adrian Hunter's avatar Adrian Hunter Committed by Namhyung Kim
Browse files

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: default avatarAdrian Hunter <adrian.hunter@intel.com>
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Like Xu <like.xu.linux@gmail.com>
Signed-off-by: default avatarNamhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240208085326.13432-2-adrian.hunter@intel.com
parent 5b9e4eef

tools/perf/Documentation/perf.txt

+2 −0
Original line number Diff line number Diff line
@@ -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.

tools/perf/builtin-report.c

+2 −0
Original line number Diff line number Diff line
@@ -1766,6 +1766,8 @@ int cmd_report(int argc, const char **argv) 
	} 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);

tools/perf/builtin-script.c

+3 −0
Original line number Diff line number Diff line
@@ -4378,6 +4378,9 @@ int cmd_script(int argc, const char **argv) 


	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);

tools/perf/util/debug.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

}

tools/perf/util/debug.h

+1 −0
Original line number Diff line number Diff line
@@ -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;