[PATCH 1/2] perf script: Make it possible to see perf's kernel and module memory mappings

From: Adrian Hunter
Date: Fri Feb 02 2024 - 06:02:33 EST


Dump kmaps if verbose > 2.

Example:

$ perf script -vvv 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@xxxxxxxxx>
---
tools/perf/builtin-script.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index b1f57401ff23..e764b319ef59 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -3806,6 +3806,16 @@ static int parse_callret_trace(const struct option *opt __maybe_unused,
return 0;
}

+static void dump_kmaps(struct perf_session *session)
+{
+ int save_verbose = verbose;
+
+ pr_debug("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;
+}
+
int cmd_script(int argc, const char **argv)
{
bool show_full_info = false;
@@ -4366,6 +4376,9 @@ int cmd_script(int argc, const char **argv)

flush_scripting();

+ if (verbose > 2)
+ dump_kmaps(session);
+
out_delete:
if (script.ptime_range) {
itrace_synth_opts__clear_time_range(&itrace_synth_opts);
--
2.34.1