[PATCH V3 09/17] perf tools: Synthesize and process mmap events for x86 PTI entry trampolines

Adrian Hunter
2018-05-22T10:56:43Z

Like the kernel text, the location of x86 PTI entry trampolines must be
recorded in the perf.data file. Like the kernel, synthesize a mmap event
for that, and add processing for it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/arch/x86/util/Build | 1 +
tools/perf/arch/x86/util/event.c | 76 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/event.c | 34 ++++++++++++++----
tools/perf/util/event.h | 8 +++++
tools/perf/util/machine.c | 28 +++++++++++++++
5 files changed, 140 insertions(+), 7 deletions(-)
create mode 100644 tools/perf/arch/x86/util/event.c

diff --git a/tools/perf/arch/x86/util/Build b/tools/perf/arch/x86/util/Build
index aa1ce5f6cc00..844b8f335532 100644
--- a/tools/perf/arch/x86/util/Build
+++ b/tools/perf/arch/x86/util/Build
@@ -5,6 +5,7 @@ libperf-y += kvm-stat.o
libperf-y += perf_regs.o
libperf-y += group.o
libperf-y += machine.o
+libperf-y += event.o

libperf-$(CONFIG_DWARF) += dwarf-regs.o
libperf-$(CONFIG_BPF_PROLOGUE) += dwarf-regs.o
diff --git a/tools/perf/arch/x86/util/event.c b/tools/perf/arch/x86/util/event.c
new file mode 100644
index 000000000000..675a0213044d
--- /dev/null
+++ b/tools/perf/arch/x86/util/event.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <linux/string.h>
+
+#include "../../util/machine.h"
+#include "../../util/tool.h"
+#include "../../util/map.h"
+#include "../../util/util.h"
+#include "../../util/debug.h"
+
+#if defined(__x86_64__)
+
+int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
+ perf_event__handler_t process,
+ struct machine *machine)
+{
+ int rc = 0;
+ struct map *pos;
+ struct map_groups *kmaps = &machine->kmaps;
+ struct maps *maps = &kmaps->maps;
+ union perf_event *event = zalloc(sizeof(event->mmap) +
+ machine->id_hdr_size);
+
+ if (!event) {
+ pr_debug("Not enough memory synthesizing mmap event "
+ "for extra kernel maps\n");
+ return -1;
+ }
+
+ for (pos = maps__first(maps); pos; pos = map__next(pos)) {
+ struct kmap *kmap;
+ size_t size;
+
+ if (!__map__is_extra_kernel_map(pos))
+ continue;
+
+ kmap = map__kmap(pos);
+
+ size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
+ PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
+ machine->id_hdr_size;
+
+ memset(event, 0, size);
+
+ event->mmap.header.type = PERF_RECORD_MMAP;
+
+ /*
+ * kernel uses 0 for user space maps, see kernel/perf_event.c
+ * __perf_event_mmap
+ */
+ if (machine__is_host(machine))
+ event->header.misc = PERF_RECORD_MISC_KERNEL;
+ else
+ event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
+
+ event->mmap.header.size = size;
+
+ event->mmap.start = pos->start;
+ event->mmap.len = pos->end - pos->start;
+ event->mmap.pgoff = pos->pgoff;
+ event->mmap.pid = machine->pid;
+
+ strlcpy(event->mmap.filename, kmap->name, PATH_MAX);
+
+ if (perf_tool__process_synth_event(tool, event, machine,
+ process) != 0) {
+ rc = -1;
+ break;
+ }
+ }
+
+ free(event);
+ return rc;
+}
+
+#endif
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index aafa9878465f..0c8ecf0c78a4 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -88,10 +88,10 @@ static const char *perf_ns__name(unsigned int id)
return perf_ns__names[id];
}

-static int perf_tool__process_synth_event(struct perf_tool *tool,
- union perf_event *event,
- struct machine *machine,
- perf_event__handler_t process)
+int perf_tool__process_synth_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct machine *machine,
+ perf_event__handler_t process)
{
struct perf_sample synth_sample = {
.pid = -1,
@@ -888,9 +888,16 @@ int kallsyms__get_function_start(const char *kallsyms_filename,
return 0;
}

-int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
- perf_event__handler_t process,
- struct machine *machine)
+int __weak perf_event__synthesize_extra_kmaps(struct perf_tool *tool __maybe_unused,
+ perf_event__handler_t process __maybe_unused,
+ struct machine *machine __maybe_unused)
+{
+ return 0;
+}
+
+static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
+ perf_event__handler_t process,
+ struct machine *machine)
{
size_t size;
struct map *map = machine__kernel_map(machine);
@@ -943,6 +950,19 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
return err;
}

+int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
+ perf_event__handler_t process,
+ struct machine *machine)
+{
+ int err;
+
+ err = __perf_event__synthesize_kernel_mmap(tool, process, machine);
+ if (err < 0)
+ return err;
+
+ return perf_event__synthesize_extra_kmaps(tool, process, machine);
+}
+
int perf_event__synthesize_thread_map2(struct perf_tool *tool,
struct thread_map *threads,
perf_event__handler_t process,
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 0f794744919c..bfa60bcafbde 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -750,6 +750,10 @@ int perf_event__process_exit(struct perf_tool *tool,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine);
+int perf_tool__process_synth_event(struct perf_tool *tool,
+ union perf_event *event,
+ struct machine *machine,
+ perf_event__handler_t process);
int perf_event__process(struct perf_tool *tool,
union perf_event *event,
struct perf_sample *sample,
@@ -796,6 +800,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
bool mmap_data,
unsigned int proc_map_timeout);

+int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
+ perf_event__handler_t process,
+ struct machine *machine);
+
size_t perf_event__fprintf_comm(union perf_event *event, FILE *fp);
size_t perf_event__fprintf_mmap(union perf_event *event, FILE *fp);
size_t perf_event__fprintf_mmap2(union perf_event *event, FILE *fp);
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index dd7ab0731167..e7b4a8b513f2 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1387,6 +1387,32 @@ static bool machine__uses_kcore(struct machine *machine)
return false;
}

+static bool perf_event__is_extra_kernel_mmap(struct machine *machine,
+ union perf_event *event)
+{
+ return machine__is(machine, "x86_64") &&
+ is_entry_trampoline(event->mmap.filename);
+}
+
+static int machine__process_extra_kernel_map(struct machine *machine,
+ union perf_event *event)
+{
+ struct map *kernel_map = machine__kernel_map(machine);
+ struct dso *kernel = kernel_map ? kernel_map->dso : NULL;
+ struct extra_kernel_map xm = {
+ .start = event->mmap.start,
+ .end = event->mmap.start + event->mmap.len,
+ .pgoff = event->mmap.pgoff,
+ };
+
+ if (kernel == NULL)
+ return -1;
+
+ strlcpy(xm.name, event->mmap.filename, KMAP_NAME_LEN);
+
+ return machine__create_extra_kernel_map(machine, kernel, &xm);
+}
+
static int machine__process_kernel_mmap_event(struct machine *machine,
union perf_event *event)
{
@@ -1490,6 +1516,8 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
*/
dso__load(kernel, machine__kernel_map(machine));
}
+ } else if (perf_event__is_extra_kernel_mmap(machine, event)) {
+ return machine__process_extra_kernel_map(machine, event);
}
return 0;
out_problem:
--
1.9.1