perf tools: Add support for PERF_RECORD_KSYMBOL_TYPE_OOL

PERF_RECORD_KSYMBOL_TYPE_OOL marks an executable page. Create a map
backed only by memory, which will be populated as necessary by text poke
events.

Committer notes:

From the patch:

OOL stands for "Out of line" code such as kprobe-replaced instructions
or optimized kprobes or ftrace trampolines.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20200512121922.8997-13-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/include/uapi/linux/perf_event.h

@@ -1049,6 +1049,11 @@ enum perf_event_type {
 enum perf_record_ksymbol_type {
 	PERF_RECORD_KSYMBOL_TYPE_UNKNOWN	= 0,
 	PERF_RECORD_KSYMBOL_TYPE_BPF		= 1,
+	/*
+	 * Out of line code such as kprobe-replaced instructions or optimized
+	 * kprobes or ftrace trampolines.
+	 */
+	PERF_RECORD_KSYMBOL_TYPE_OOL		= 2,
 	PERF_RECORD_KSYMBOL_TYPE_MAX		/* non-ABI */
 };
 

tools/perf/util/dso.c

@@ -208,6 +208,7 @@ int dso__read_binary_type_filename(const struct dso *dso,
 	case DSO_BINARY_TYPE__JAVA_JIT:
 	case DSO_BINARY_TYPE__BPF_PROG_INFO:
 	case DSO_BINARY_TYPE__BPF_IMAGE:
+	case DSO_BINARY_TYPE__OOL:
 	case DSO_BINARY_TYPE__NOT_FOUND:
 		ret = -1;
 		break;
@@ -898,6 +899,8 @@ static struct dso_cache *dso_cache__populate(struct dso *dso,
 
 	if (dso->binary_type == DSO_BINARY_TYPE__BPF_PROG_INFO)
 		*ret = bpf_read(dso, cache_offset, cache->data);
+	else if (dso->binary_type == DSO_BINARY_TYPE__OOL)
+		*ret = DSO__DATA_CACHE_SIZE;
 	else
 		*ret = file_read(dso, machine, cache_offset, cache->data);
 

tools/perf/util/dso.h

@@ -42,6 +42,7 @@ enum dso_binary_type {
 	DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 	DSO_BINARY_TYPE__BPF_PROG_INFO,
 	DSO_BINARY_TYPE__BPF_IMAGE,
+	DSO_BINARY_TYPE__OOL,
 	DSO_BINARY_TYPE__NOT_FOUND,
 };
 

tools/perf/util/machine.c

@@ -762,6 +762,12 @@ static int machine__process_ksymbol_register(struct machine *machine,
 			return -ENOMEM;
 		}
 
+		if (event->ksymbol.ksym_type == PERF_RECORD_KSYMBOL_TYPE_OOL) {
+			map->dso->binary_type = DSO_BINARY_TYPE__OOL;
+			map->dso->data.file_size = event->ksymbol.len;
+			dso__set_loaded(map->dso);
+		}
+
 		map->start = event->ksymbol.addr;
 		map->end = map->start + event->ksymbol.len;
 		maps__insert(&machine->kmaps, map);

tools/perf/util/map.c

@@ -267,6 +267,11 @@ bool __map__is_bpf_prog(const struct map *map)
 	return name && (strstr(name, "bpf_prog_") == name);
 }
 
+bool __map__is_ool(const struct map *map)
+{
+	return map->dso && map->dso->binary_type == DSO_BINARY_TYPE__OOL;
+}
+
 bool map__has_symbols(const struct map *map)
 {
 	return dso__has_symbols(map->dso);

tools/perf/util/map.h

@@ -147,11 +147,12 @@ int map__set_kallsyms_ref_reloc_sym(struct map *map, const char *symbol_name,
 bool __map__is_kernel(const struct map *map);
 bool __map__is_extra_kernel_map(const struct map *map);
 bool __map__is_bpf_prog(const struct map *map);
+bool __map__is_ool(const struct map *map);
 
 static inline bool __map__is_kmodule(const struct map *map)
 {
 	return !__map__is_kernel(map) && !__map__is_extra_kernel_map(map) &&
-	       !__map__is_bpf_prog(map);
+	       !__map__is_bpf_prog(map) && !__map__is_ool(map);
 }
 
 bool map__has_symbols(const struct map *map);

tools/perf/util/symbol.c

@@ -1565,6 +1565,7 @@ static bool dso__is_compatible_symtab_type(struct dso *dso, bool kmod,
 
 	case DSO_BINARY_TYPE__BPF_PROG_INFO:
 	case DSO_BINARY_TYPE__BPF_IMAGE:
+	case DSO_BINARY_TYPE__OOL:
 	case DSO_BINARY_TYPE__NOT_FOUND:
 	default:
 		return false;