1 files changed, 747 insertions, 0 deletions

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
new file mode 100644
index 000000000..95feb6ef3
--- /dev/null
+++ b/tools/perf/tests/code-reading.c
@@ -0,0 +1,747 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/param.h>
+#include <perf/cpumap.h>
+#include <perf/evlist.h>
+#include <perf/mmap.h>
+
+#include "debug.h"
+#include "dso.h"
+#include "env.h"
+#include "parse-events.h"
+#include "trace-event.h"
+#include "evlist.h"
+#include "evsel.h"
+#include "thread_map.h"
+#include "machine.h"
+#include "map.h"
+#include "symbol.h"
+#include "event.h"
+#include "record.h"
+#include "util/mmap.h"
+#include "util/string2.h"
+#include "util/synthetic-events.h"
+#include "thread.h"
+
+#include "tests.h"
+
+#include <linux/ctype.h>
+
+#define BUFSZ	1024
+#define READLEN	128
+
+struct state {
+	u64 done[1024];
+	size_t done_cnt;
+};
+
+static size_t read_objdump_chunk(const char **line, unsigned char **buf,
+				 size_t *buf_len)
+{
+	size_t bytes_read = 0;
+	unsigned char *chunk_start = *buf;
+
+	/* Read bytes */
+	while (*buf_len > 0) {
+		char c1, c2;
+
+		/* Get 2 hex digits */
+		c1 = *(*line)++;
+		if (!isxdigit(c1))
+			break;
+		c2 = *(*line)++;
+		if (!isxdigit(c2))
+			break;
+
+		/* Store byte and advance buf */
+		**buf = (hex(c1) << 4) | hex(c2);
+		(*buf)++;
+		(*buf_len)--;
+		bytes_read++;
+
+		/* End of chunk? */
+		if (isspace(**line))
+			break;
+	}
+
+	/*
+	 * objdump will display raw insn as LE if code endian
+	 * is LE and bytes_per_chunk > 1. In that case reverse
+	 * the chunk we just read.
+	 *
+	 * see disassemble_bytes() at binutils/objdump.c for details
+	 * how objdump chooses display endian)
+	 */
+	if (bytes_read > 1 && !bigendian()) {
+		unsigned char *chunk_end = chunk_start + bytes_read - 1;
+		unsigned char tmp;
+
+		while (chunk_start < chunk_end) {
+			tmp = *chunk_start;
+			*chunk_start = *chunk_end;
+			*chunk_end = tmp;
+			chunk_start++;
+			chunk_end--;
+		}
+	}
+
+	return bytes_read;
+}
+
+static size_t read_objdump_line(const char *line, unsigned char *buf,
+				size_t buf_len)
+{
+	const char *p;
+	size_t ret, bytes_read = 0;
+
+	/* Skip to a colon */
+	p = strchr(line, ':');
+	if (!p)
+		return 0;
+	p++;
+
+	/* Skip initial spaces */
+	while (*p) {
+		if (!isspace(*p))
+			break;
+		p++;
+	}
+
+	do {
+		ret = read_objdump_chunk(&p, &buf, &buf_len);
+		bytes_read += ret;
+		p++;
+	} while (ret > 0);
+
+	/* return number of successfully read bytes */
+	return bytes_read;
+}
+
+static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
+{
+	char *line = NULL;
+	size_t line_len, off_last = 0;
+	ssize_t ret;
+	int err = 0;
+	u64 addr, last_addr = start_addr;
+
+	while (off_last < *len) {
+		size_t off, read_bytes, written_bytes;
+		unsigned char tmp[BUFSZ];
+
+		ret = getline(&line, &line_len, f);
+		if (feof(f))
+			break;
+		if (ret < 0) {
+			pr_debug("getline failed\n");
+			err = -1;
+			break;
+		}
+
+		/* read objdump data into temporary buffer */
+		read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
+		if (!read_bytes)
+			continue;
+
+		if (sscanf(line, "%"PRIx64, &addr) != 1)
+			continue;
+		if (addr < last_addr) {
+			pr_debug("addr going backwards, read beyond section?\n");
+			break;
+		}
+		last_addr = addr;
+
+		/* copy it from temporary buffer to 'buf' according
+		 * to address on current objdump line */
+		off = addr - start_addr;
+		if (off >= *len)
+			break;
+		written_bytes = MIN(read_bytes, *len - off);
+		memcpy(buf + off, tmp, written_bytes);
+		off_last = off + written_bytes;
+	}
+
+	/* len returns number of bytes that could not be read */
+	*len -= off_last;
+
+	free(line);
+
+	return err;
+}
+
+static int read_via_objdump(const char *filename, u64 addr, void *buf,
+			    size_t len)
+{
+	char cmd[PATH_MAX * 2];
+	const char *fmt;
+	FILE *f;
+	int ret;
+
+	fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
+	ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
+		       filename);
+	if (ret <= 0 || (size_t)ret >= sizeof(cmd))
+		return -1;
+
+	pr_debug("Objdump command is: %s\n", cmd);
+
+	/* Ignore objdump errors */
+	strcat(cmd, " 2>/dev/null");
+
+	f = popen(cmd, "r");
+	if (!f) {
+		pr_debug("popen failed\n");
+		return -1;
+	}
+
+	ret = read_objdump_output(f, buf, &len, addr);
+	if (len) {
+		pr_debug("objdump read too few bytes: %zd\n", len);
+		if (!ret)
+			ret = len;
+	}
+
+	pclose(f);
+
+	return ret;
+}
+
+static void dump_buf(unsigned char *buf, size_t len)
+{
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		pr_debug("0x%02x ", buf[i]);
+		if (i % 16 == 15)
+			pr_debug("\n");
+	}
+	pr_debug("\n");
+}
+
+static int read_object_code(u64 addr, size_t len, u8 cpumode,
+			    struct thread *thread, struct state *state)
+{
+	struct addr_location al;
+	unsigned char buf1[BUFSZ] = {0};
+	unsigned char buf2[BUFSZ] = {0};
+	size_t ret_len;
+	u64 objdump_addr;
+	const char *objdump_name;
+	char decomp_name[KMOD_DECOMP_LEN];
+	bool decomp = false;
+	int ret;
+
+	pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
+
+	if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) {
+		if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
+			pr_debug("Hypervisor address can not be resolved - skipping\n");
+			return 0;
+		}
+
+		pr_debug("thread__find_map failed\n");
+		return -1;
+	}
+
+	pr_debug("File is: %s\n", al.map->dso->long_name);
+
+	if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
+	    !dso__is_kcore(al.map->dso)) {
+		pr_debug("Unexpected kernel address - skipping\n");
+		return 0;
+	}
+
+	pr_debug("On file address is: %#"PRIx64"\n", al.addr);
+
+	if (len > BUFSZ)
+		len = BUFSZ;
+
+	/* Do not go off the map */
+	if (addr + len > al.map->end)
+		len = al.map->end - addr;
+
+	/* Read the object code using perf */
+	ret_len = dso__data_read_offset(al.map->dso, thread->maps->machine,
+					al.addr, buf1, len);
+	if (ret_len != len) {
+		pr_debug("dso__data_read_offset failed\n");
+		return -1;
+	}
+
+	/*
+	 * Converting addresses for use by objdump requires more information.
+	 * map__load() does that.  See map__rip_2objdump() for details.
+	 */
+	if (map__load(al.map))
+		return -1;
+
+	/* objdump struggles with kcore - try each map only once */
+	if (dso__is_kcore(al.map->dso)) {
+		size_t d;
+
+		for (d = 0; d < state->done_cnt; d++) {
+			if (state->done[d] == al.map->start) {
+				pr_debug("kcore map tested already");
+				pr_debug(" - skipping\n");
+				return 0;
+			}
+		}
+		if (state->done_cnt >= ARRAY_SIZE(state->done)) {
+			pr_debug("Too many kcore maps - skipping\n");
+			return 0;
+		}
+		state->done[state->done_cnt++] = al.map->start;
+	}
+
+	objdump_name = al.map->dso->long_name;
+	if (dso__needs_decompress(al.map->dso)) {
+		if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
+						 decomp_name,
+						 sizeof(decomp_name)) < 0) {
+			pr_debug("decompression failed\n");
+			return -1;
+		}
+
+		decomp = true;
+		objdump_name = decomp_name;
+	}
+
+	/* Read the object code using objdump */
+	objdump_addr = map__rip_2objdump(al.map, al.addr);
+	ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
+
+	if (decomp)
+		unlink(objdump_name);
+
+	if (ret > 0) {
+		/*
+		 * The kernel maps are inaccurate - assume objdump is right in
+		 * that case.
+		 */
+		if (cpumode == PERF_RECORD_MISC_KERNEL ||
+		    cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
+			len -= ret;
+			if (len) {
+				pr_debug("Reducing len to %zu\n", len);
+			} else if (dso__is_kcore(al.map->dso)) {
+				/*
+				 * objdump cannot handle very large segments
+				 * that may be found in kcore.
+				 */
+				pr_debug("objdump failed for kcore");
+				pr_debug(" - skipping\n");
+				return 0;
+			} else {
+				return -1;
+			}
+		}
+	}
+	if (ret < 0) {
+		pr_debug("read_via_objdump failed\n");
+		return -1;
+	}
+
+	/* The results should be identical */
+	if (memcmp(buf1, buf2, len)) {
+		pr_debug("Bytes read differ from those read by objdump\n");
+		pr_debug("buf1 (dso):\n");
+		dump_buf(buf1, len);
+		pr_debug("buf2 (objdump):\n");
+		dump_buf(buf2, len);
+		return -1;
+	}
+	pr_debug("Bytes read match those read by objdump\n");
+
+	return 0;
+}
+
+static int process_sample_event(struct machine *machine,
+				struct evlist *evlist,
+				union perf_event *event, struct state *state)
+{
+	struct perf_sample sample;
+	struct thread *thread;
+	int ret;
+
+	if (evlist__parse_sample(evlist, event, &sample)) {
+		pr_debug("evlist__parse_sample failed\n");
+		return -1;
+	}
+
+	thread = machine__findnew_thread(machine, sample.pid, sample.tid);
+	if (!thread) {
+		pr_debug("machine__findnew_thread failed\n");
+		return -1;
+	}
+
+	ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
+	thread__put(thread);
+	return ret;
+}
+
+static int process_event(struct machine *machine, struct evlist *evlist,
+			 union perf_event *event, struct state *state)
+{
+	if (event->header.type == PERF_RECORD_SAMPLE)
+		return process_sample_event(machine, evlist, event, state);
+
+	if (event->header.type == PERF_RECORD_THROTTLE ||
+	    event->header.type == PERF_RECORD_UNTHROTTLE)
+		return 0;
+
+	if (event->header.type < PERF_RECORD_MAX) {
+		int ret;
+
+		ret = machine__process_event(machine, event, NULL);
+		if (ret < 0)
+			pr_debug("machine__process_event failed, event type %u\n",
+				 event->header.type);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int process_events(struct machine *machine, struct evlist *evlist,
+			  struct state *state)
+{
+	union perf_event *event;
+	struct mmap *md;
+	int i, ret;
+
+	for (i = 0; i < evlist->core.nr_mmaps; i++) {
+		md = &evlist->mmap[i];
+		if (perf_mmap__read_init(&md->core) < 0)
+			continue;
+
+		while ((event = perf_mmap__read_event(&md->core)) != NULL) {
+			ret = process_event(machine, evlist, event, state);
+			perf_mmap__consume(&md->core);
+			if (ret < 0)
+				return ret;
+		}
+		perf_mmap__read_done(&md->core);
+	}
+	return 0;
+}
+
+static int comp(const void *a, const void *b)
+{
+	return *(int *)a - *(int *)b;
+}
+
+static void do_sort_something(void)
+{
+	int buf[40960], i;
+
+	for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
+		buf[i] = ARRAY_SIZE(buf) - i - 1;
+
+	qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
+
+	for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
+		if (buf[i] != i) {
+			pr_debug("qsort failed\n");
+			break;
+		}
+	}
+}
+
+static void sort_something(void)
+{
+	int i;
+
+	for (i = 0; i < 10; i++)
+		do_sort_something();
+}
+
+static void syscall_something(void)
+{
+	int pipefd[2];
+	int i;
+
+	for (i = 0; i < 1000; i++) {
+		if (pipe(pipefd) < 0) {
+			pr_debug("pipe failed\n");
+			break;
+		}
+		close(pipefd[1]);
+		close(pipefd[0]);
+	}
+}
+
+static void fs_something(void)
+{
+	const char *test_file_name = "temp-perf-code-reading-test-file--";
+	FILE *f;
+	int i;
+
+	for (i = 0; i < 1000; i++) {
+		f = fopen(test_file_name, "w+");
+		if (f) {
+			fclose(f);
+			unlink(test_file_name);
+		}
+	}
+}
+
+#ifdef __s390x__
+#include "header.h" // for get_cpuid()
+#endif
+
+static const char *do_determine_event(bool excl_kernel)
+{
+	const char *event = excl_kernel ? "cycles:u" : "cycles";
+
+#ifdef __s390x__
+	char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
+	unsigned int family;
+	int ret, cpum_cf_a;
+
+	if (get_cpuid(cpuid, sizeof(cpuid)))
+		goto out_clocks;
+	ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
+		     model, cpum_cf_v, &cpum_cf_a);
+	if (ret != 5)		 /* Not available */
+		goto out_clocks;
+	if (excl_kernel && (cpum_cf_a & 4))
+		return event;
+	if (!excl_kernel && (cpum_cf_a & 2))
+		return event;
+
+	/* Fall through: missing authorization */
+out_clocks:
+	event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
+
+#endif
+	return event;
+}
+
+static void do_something(void)
+{
+	fs_something();
+
+	sort_something();
+
+	syscall_something();
+}
+
+enum {
+	TEST_CODE_READING_OK,
+	TEST_CODE_READING_NO_VMLINUX,
+	TEST_CODE_READING_NO_KCORE,
+	TEST_CODE_READING_NO_ACCESS,
+	TEST_CODE_READING_NO_KERNEL_OBJ,
+};
+
+static int do_test_code_reading(bool try_kcore)
+{
+	struct machine *machine;
+	struct thread *thread;
+	struct record_opts opts = {
+		.mmap_pages	     = UINT_MAX,
+		.user_freq	     = UINT_MAX,
+		.user_interval	     = ULLONG_MAX,
+		.freq		     = 500,
+		.target		     = {
+			.uses_mmap   = true,
+		},
+	};
+	struct state state = {
+		.done_cnt = 0,
+	};
+	struct perf_thread_map *threads = NULL;
+	struct perf_cpu_map *cpus = NULL;
+	struct evlist *evlist = NULL;
+	struct evsel *evsel = NULL;
+	int err = -1, ret;
+	pid_t pid;
+	struct map *map;
+	bool have_vmlinux, have_kcore, excl_kernel = false;
+
+	pid = getpid();
+
+	machine = machine__new_host();
+	machine->env = &perf_env;
+
+	ret = machine__create_kernel_maps(machine);
+	if (ret < 0) {
+		pr_debug("machine__create_kernel_maps failed\n");
+		goto out_err;
+	}
+
+	/* Force the use of kallsyms instead of vmlinux to try kcore */
+	if (try_kcore)
+		symbol_conf.kallsyms_name = "/proc/kallsyms";
+
+	/* Load kernel map */
+	map = machine__kernel_map(machine);
+	ret = map__load(map);
+	if (ret < 0) {
+		pr_debug("map__load failed\n");
+		goto out_err;
+	}
+	have_vmlinux = dso__is_vmlinux(map->dso);
+	have_kcore = dso__is_kcore(map->dso);
+
+	/* 2nd time through we just try kcore */
+	if (try_kcore && !have_kcore)
+		return TEST_CODE_READING_NO_KCORE;
+
+	/* No point getting kernel events if there is no kernel object */
+	if (!have_vmlinux && !have_kcore)
+		excl_kernel = true;
+
+	threads = thread_map__new_by_tid(pid);
+	if (!threads) {
+		pr_debug("thread_map__new_by_tid failed\n");
+		goto out_err;
+	}
+
+	ret = perf_event__synthesize_thread_map(NULL, threads,
+						perf_event__process, machine,
+						true, false);
+	if (ret < 0) {
+		pr_debug("perf_event__synthesize_thread_map failed\n");
+		goto out_err;
+	}
+
+	thread = machine__findnew_thread(machine, pid, pid);
+	if (!thread) {
+		pr_debug("machine__findnew_thread failed\n");
+		goto out_put;
+	}
+
+	cpus = perf_cpu_map__new(NULL);
+	if (!cpus) {
+		pr_debug("perf_cpu_map__new failed\n");
+		goto out_put;
+	}
+
+	while (1) {
+		const char *str;
+
+		evlist = evlist__new();
+		if (!evlist) {
+			pr_debug("evlist__new failed\n");
+			goto out_put;
+		}
+
+		perf_evlist__set_maps(&evlist->core, cpus, threads);
+
+		str = do_determine_event(excl_kernel);
+		pr_debug("Parsing event '%s'\n", str);
+		ret = parse_event(evlist, str);
+		if (ret < 0) {
+			pr_debug("parse_events failed\n");
+			goto out_put;
+		}
+
+		evlist__config(evlist, &opts, NULL);
+
+		evsel = evlist__first(evlist);
+
+		evsel->core.attr.comm = 1;
+		evsel->core.attr.disabled = 1;
+		evsel->core.attr.enable_on_exec = 0;
+
+		ret = evlist__open(evlist);
+		if (ret < 0) {
+			if (!excl_kernel) {
+				excl_kernel = true;
+				/*
+				 * Both cpus and threads are now owned by evlist
+				 * and will be freed by following perf_evlist__set_maps
+				 * call. Getting reference to keep them alive.
+				 */
+				perf_cpu_map__get(cpus);
+				perf_thread_map__get(threads);
+				perf_evlist__set_maps(&evlist->core, NULL, NULL);
+				evlist__delete(evlist);
+				evlist = NULL;
+				continue;
+			}
+
+			if (verbose > 0) {
+				char errbuf[512];
+				evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
+				pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
+			}
+
+			goto out_put;
+		}
+		break;
+	}
+
+	ret = evlist__mmap(evlist, UINT_MAX);
+	if (ret < 0) {
+		pr_debug("evlist__mmap failed\n");
+		goto out_put;
+	}
+
+	evlist__enable(evlist);
+
+	do_something();
+
+	evlist__disable(evlist);
+
+	ret = process_events(machine, evlist, &state);
+	if (ret < 0)
+		goto out_put;
+
+	if (!have_vmlinux && !have_kcore && !try_kcore)
+		err = TEST_CODE_READING_NO_KERNEL_OBJ;
+	else if (!have_vmlinux && !try_kcore)
+		err = TEST_CODE_READING_NO_VMLINUX;
+	else if (excl_kernel)
+		err = TEST_CODE_READING_NO_ACCESS;
+	else
+		err = TEST_CODE_READING_OK;
+out_put:
+	thread__put(thread);
+out_err:
+	evlist__delete(evlist);
+	perf_cpu_map__put(cpus);
+	perf_thread_map__put(threads);
+	machine__delete_threads(machine);
+	machine__delete(machine);
+
+	return err;
+}
+
+static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
+{
+	int ret;
+
+	ret = do_test_code_reading(false);
+	if (!ret)
+		ret = do_test_code_reading(true);
+
+	switch (ret) {
+	case TEST_CODE_READING_OK:
+		return 0;
+	case TEST_CODE_READING_NO_VMLINUX:
+		pr_debug("no vmlinux\n");
+		return 0;
+	case TEST_CODE_READING_NO_KCORE:
+		pr_debug("no kcore\n");
+		return 0;
+	case TEST_CODE_READING_NO_ACCESS:
+		pr_debug("no access\n");
+		return 0;
+	case TEST_CODE_READING_NO_KERNEL_OBJ:
+		pr_debug("no kernel obj\n");
+		return 0;
+	default:
+		return -1;
+	};
+}
+
+DEFINE_SUITE("Object code reading", code_reading);