[mirror_ubuntu-focal-kernel.git] / tools / perf / tests / code-reading.c

// 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 "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/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 unsigned int hex(char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';
	if (c >= 'a' && c <= 'f')
		return c - 'a' + 10;
	return c - 'A' + 10;
}

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];
	unsigned char buf2[BUFSZ];
	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->mg->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 (perf_evlist__parse_sample(evlist, event, &sample)) {
		pr_debug("perf_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) < 0)
			continue;

		while ((event = perf_mmap__read_event(md)) != NULL) {
			ret = process_event(machine, evlist, event, state);
			perf_mmap__consume(md);
			if (ret < 0)
				return ret;
		}
		perf_mmap__read_done(md);
	}
	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, 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("perf_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_events(evlist, str, NULL);
		if (ret < 0) {
			pr_debug("parse_events failed\n");
			goto out_put;
		}

		perf_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 refference 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];
				perf_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:

	if (evlist) {
		evlist__delete(evlist);
	} else {
		perf_cpu_map__put(cpus);
		perf_thread_map__put(threads);
	}
	machine__delete_threads(machine);
	machine__delete(machine);

	return err;
}

int test__code_reading(struct test *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;
	};
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	#include <errno.h>
	3	#include <linux/kernel.h>
	4	#include <linux/types.h>
	5	#include <inttypes.h>
	6	#include <stdlib.h>
	7	#include <unistd.h>
	8	#include <stdio.h>
	9	#include <string.h>
	10	#include <sys/param.h>
	11	#include <perf/cpumap.h>
	12	#include <perf/evlist.h>
	13
	14	#include "debug.h"
	15	#include "dso.h"
	16	#include "env.h"
	17	#include "parse-events.h"
	18	#include "trace-event.h"
	19	#include "evlist.h"
	20	#include "evsel.h"
	21	#include "thread_map.h"
	22	#include "machine.h"
	23	#include "map.h"
	24	#include "symbol.h"
	25	#include "event.h"
	26	#include "record.h"
	27	#include "util/mmap.h"
	28	#include "util/synthetic-events.h"
	29	#include "thread.h"
	30
	31	#include "tests.h"
	32
	33	#include <linux/ctype.h>
	34
	35	#define BUFSZ 1024
	36	#define READLEN 128
	37
	38	struct state {
	39	u64 done[1024];
	40	size_t done_cnt;
	41	};
	42
	43	static unsigned int hex(char c)
	44	{
	45	if (c >= '0' && c <= '9')
	46	return c - '0';
	47	if (c >= 'a' && c <= 'f')
	48	return c - 'a' + 10;
	49	return c - 'A' + 10;
	50	}
	51
	52	static size_t read_objdump_chunk(const char line, unsigned char buf,
	53	size_t *buf_len)
	54	{
	55	size_t bytes_read = 0;
	56	unsigned char chunk_start = buf;
	57
	58	/* Read bytes */
	59	while (*buf_len > 0) {
	60	char c1, c2;
	61
	62	/* Get 2 hex digits */
	63	c1 = (line)++;
	64	if (!isxdigit(c1))
	65	break;
	66	c2 = (line)++;
	67	if (!isxdigit(c2))
	68	break;
	69
	70	/* Store byte and advance buf */
	71	**buf = (hex(c1) << 4) \| hex(c2);
	72	(*buf)++;
	73	(*buf_len)--;
	74	bytes_read++;
	75
	76	/* End of chunk? */
	77	if (isspace(**line))
	78	break;
	79	}
	80
	81	/*
	82	* objdump will display raw insn as LE if code endian
	83	* is LE and bytes_per_chunk > 1. In that case reverse
	84	* the chunk we just read.
	85	*
	86	* see disassemble_bytes() at binutils/objdump.c for details
	87	* how objdump chooses display endian)
	88	*/
	89	if (bytes_read > 1 && !bigendian()) {
	90	unsigned char *chunk_end = chunk_start + bytes_read - 1;
	91	unsigned char tmp;
	92
	93	while (chunk_start < chunk_end) {
	94	tmp = *chunk_start;
	95	chunk_start = chunk_end;
	96	*chunk_end = tmp;
	97	chunk_start++;
	98	chunk_end--;
	99	}
	100	}
	101
	102	return bytes_read;
	103	}
	104
	105	static size_t read_objdump_line(const char line, unsigned char buf,
	106	size_t buf_len)
	107	{
	108	const char *p;
	109	size_t ret, bytes_read = 0;
	110
	111	/* Skip to a colon */
	112	p = strchr(line, ':');
	113	if (!p)
	114	return 0;
	115	p++;
	116
	117	/* Skip initial spaces */
	118	while (*p) {
	119	if (!isspace(*p))
	120	break;
	121	p++;
	122	}
	123
	124	do {
	125	ret = read_objdump_chunk(&p, &buf, &buf_len);
	126	bytes_read += ret;
	127	p++;
	128	} while (ret > 0);
	129
	130	/* return number of successfully read bytes */
	131	return bytes_read;
	132	}
	133
	134	static int read_objdump_output(FILE f, void buf, size_t *len, u64 start_addr)
	135	{
	136	char *line = NULL;
	137	size_t line_len, off_last = 0;
	138	ssize_t ret;
	139	int err = 0;
	140	u64 addr, last_addr = start_addr;
	141
	142	while (off_last < *len) {
	143	size_t off, read_bytes, written_bytes;
	144	unsigned char tmp[BUFSZ];
	145
	146	ret = getline(&line, &line_len, f);
	147	if (feof(f))
	148	break;
	149	if (ret < 0) {
	150	pr_debug("getline failed\n");
	151	err = -1;
	152	break;
	153	}
	154
	155	/* read objdump data into temporary buffer */
	156	read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
	157	if (!read_bytes)
	158	continue;
	159
	160	if (sscanf(line, "%"PRIx64, &addr) != 1)
	161	continue;
	162	if (addr < last_addr) {
	163	pr_debug("addr going backwards, read beyond section?\n");
	164	break;
	165	}
	166	last_addr = addr;
	167
	168	/* copy it from temporary buffer to 'buf' according
	169	* to address on current objdump line */
	170	off = addr - start_addr;
	171	if (off >= *len)
	172	break;
	173	written_bytes = MIN(read_bytes, *len - off);
	174	memcpy(buf + off, tmp, written_bytes);
	175	off_last = off + written_bytes;
	176	}
	177
	178	/* len returns number of bytes that could not be read */
	179	*len -= off_last;
	180
	181	free(line);
	182
	183	return err;
	184	}
	185
	186	static int read_via_objdump(const char filename, u64 addr, void buf,
	187	size_t len)
	188	{
	189	char cmd[PATH_MAX * 2];
	190	const char *fmt;
	191	FILE *f;
	192	int ret;
	193
	194	fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
	195	ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
	196	filename);
	197	if (ret <= 0 \|\| (size_t)ret >= sizeof(cmd))
	198	return -1;
	199
	200	pr_debug("Objdump command is: %s\n", cmd);
	201
	202	/* Ignore objdump errors */
	203	strcat(cmd, " 2>/dev/null");
	204
	205	f = popen(cmd, "r");
	206	if (!f) {
	207	pr_debug("popen failed\n");
	208	return -1;
	209	}
	210
	211	ret = read_objdump_output(f, buf, &len, addr);
	212	if (len) {
	213	pr_debug("objdump read too few bytes: %zd\n", len);
	214	if (!ret)
	215	ret = len;
	216	}
	217
	218	pclose(f);
	219
	220	return ret;
	221	}
	222
	223	static void dump_buf(unsigned char *buf, size_t len)
	224	{
	225	size_t i;
	226
	227	for (i = 0; i < len; i++) {
	228	pr_debug("0x%02x ", buf[i]);
	229	if (i % 16 == 15)
	230	pr_debug("\n");
	231	}
	232	pr_debug("\n");
	233	}
	234
	235	static int read_object_code(u64 addr, size_t len, u8 cpumode,
	236	struct thread thread, struct state state)
	237	{
	238	struct addr_location al;
	239	unsigned char buf1[BUFSZ];
	240	unsigned char buf2[BUFSZ];
	241	size_t ret_len;
	242	u64 objdump_addr;
	243	const char *objdump_name;
	244	char decomp_name[KMOD_DECOMP_LEN];
	245	bool decomp = false;
	246	int ret;
	247
	248	pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
	249
	250	if (!thread__find_map(thread, cpumode, addr, &al) \|\| !al.map->dso) {
	251	if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
	252	pr_debug("Hypervisor address can not be resolved - skipping\n");
	253	return 0;
	254	}
	255
	256	pr_debug("thread__find_map failed\n");
	257	return -1;
	258	}
	259
	260	pr_debug("File is: %s\n", al.map->dso->long_name);
	261
	262	if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
	263	!dso__is_kcore(al.map->dso)) {
	264	pr_debug("Unexpected kernel address - skipping\n");
	265	return 0;
	266	}
	267
	268	pr_debug("On file address is: %#"PRIx64"\n", al.addr);
	269
	270	if (len > BUFSZ)
	271	len = BUFSZ;
	272
	273	/* Do not go off the map */
	274	if (addr + len > al.map->end)
	275	len = al.map->end - addr;
	276
	277	/* Read the object code using perf */
	278	ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
	279	al.addr, buf1, len);
	280	if (ret_len != len) {
	281	pr_debug("dso__data_read_offset failed\n");
	282	return -1;
	283	}
	284
	285	/*
	286	* Converting addresses for use by objdump requires more information.
	287	* map__load() does that. See map__rip_2objdump() for details.
	288	*/
	289	if (map__load(al.map))
	290	return -1;
	291
	292	/* objdump struggles with kcore - try each map only once */
	293	if (dso__is_kcore(al.map->dso)) {
	294	size_t d;
	295
	296	for (d = 0; d < state->done_cnt; d++) {
	297	if (state->done[d] == al.map->start) {
	298	pr_debug("kcore map tested already");
	299	pr_debug(" - skipping\n");
	300	return 0;
	301	}
	302	}
	303	if (state->done_cnt >= ARRAY_SIZE(state->done)) {
	304	pr_debug("Too many kcore maps - skipping\n");
	305	return 0;
	306	}
	307	state->done[state->done_cnt++] = al.map->start;
	308	}
	309
	310	objdump_name = al.map->dso->long_name;
	311	if (dso__needs_decompress(al.map->dso)) {
	312	if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
	313	decomp_name,
	314	sizeof(decomp_name)) < 0) {
	315	pr_debug("decompression failed\n");
	316	return -1;
	317	}
	318
	319	decomp = true;
	320	objdump_name = decomp_name;
	321	}
	322
	323	/* Read the object code using objdump */
	324	objdump_addr = map__rip_2objdump(al.map, al.addr);
	325	ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
	326
	327	if (decomp)
	328	unlink(objdump_name);
	329
	330	if (ret > 0) {
	331	/*
	332	* The kernel maps are inaccurate - assume objdump is right in
	333	* that case.
	334	*/
	335	if (cpumode == PERF_RECORD_MISC_KERNEL \|\|
	336	cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
	337	len -= ret;
	338	if (len) {
	339	pr_debug("Reducing len to %zu\n", len);
	340	} else if (dso__is_kcore(al.map->dso)) {
	341	/*
	342	* objdump cannot handle very large segments
	343	* that may be found in kcore.
	344	*/
	345	pr_debug("objdump failed for kcore");
	346	pr_debug(" - skipping\n");
	347	return 0;
	348	} else {
	349	return -1;
	350	}
	351	}
	352	}
	353	if (ret < 0) {
	354	pr_debug("read_via_objdump failed\n");
	355	return -1;
	356	}
	357
	358	/* The results should be identical */
	359	if (memcmp(buf1, buf2, len)) {
	360	pr_debug("Bytes read differ from those read by objdump\n");
	361	pr_debug("buf1 (dso):\n");
	362	dump_buf(buf1, len);
	363	pr_debug("buf2 (objdump):\n");
	364	dump_buf(buf2, len);
	365	return -1;
	366	}
	367	pr_debug("Bytes read match those read by objdump\n");
	368
	369	return 0;
	370	}
	371
	372	static int process_sample_event(struct machine *machine,
	373	struct evlist *evlist,
	374	union perf_event event, struct state state)
	375	{
	376	struct perf_sample sample;
	377	struct thread *thread;
	378	int ret;
	379
	380	if (perf_evlist__parse_sample(evlist, event, &sample)) {
	381	pr_debug("perf_evlist__parse_sample failed\n");
	382	return -1;
	383	}
	384
	385	thread = machine__findnew_thread(machine, sample.pid, sample.tid);
	386	if (!thread) {
	387	pr_debug("machine__findnew_thread failed\n");
	388	return -1;
	389	}
	390
	391	ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
	392	thread__put(thread);
	393	return ret;
	394	}
	395
	396	static int process_event(struct machine machine, struct evlist evlist,
	397	union perf_event event, struct state state)
	398	{
	399	if (event->header.type == PERF_RECORD_SAMPLE)
	400	return process_sample_event(machine, evlist, event, state);
	401
	402	if (event->header.type == PERF_RECORD_THROTTLE \|\|
	403	event->header.type == PERF_RECORD_UNTHROTTLE)
	404	return 0;
	405
	406	if (event->header.type < PERF_RECORD_MAX) {
	407	int ret;
	408
	409	ret = machine__process_event(machine, event, NULL);
	410	if (ret < 0)
	411	pr_debug("machine__process_event failed, event type %u\n",
	412	event->header.type);
	413	return ret;
	414	}
	415
	416	return 0;
	417	}
	418
	419	static int process_events(struct machine machine, struct evlist evlist,
	420	struct state *state)
	421	{
	422	union perf_event *event;
	423	struct mmap *md;
	424	int i, ret;
	425
	426	for (i = 0; i < evlist->core.nr_mmaps; i++) {
	427	md = &evlist->mmap[i];
	428	if (perf_mmap__read_init(md) < 0)
	429	continue;
	430
	431	while ((event = perf_mmap__read_event(md)) != NULL) {
	432	ret = process_event(machine, evlist, event, state);
	433	perf_mmap__consume(md);
	434	if (ret < 0)
	435	return ret;
	436	}
	437	perf_mmap__read_done(md);
	438	}
	439	return 0;
	440	}
	441
	442	static int comp(const void a, const void b)
	443	{
	444	return (int )a - (int )b;
	445	}
	446
	447	static void do_sort_something(void)
	448	{
	449	int buf[40960], i;
	450
	451	for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
	452	buf[i] = ARRAY_SIZE(buf) - i - 1;
	453
	454	qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
	455
	456	for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
	457	if (buf[i] != i) {
	458	pr_debug("qsort failed\n");
	459	break;
	460	}
	461	}
	462	}
	463
	464	static void sort_something(void)
	465	{
	466	int i;
	467
	468	for (i = 0; i < 10; i++)
	469	do_sort_something();
	470	}
	471
	472	static void syscall_something(void)
	473	{
	474	int pipefd[2];
	475	int i;
	476
	477	for (i = 0; i < 1000; i++) {
	478	if (pipe(pipefd) < 0) {
	479	pr_debug("pipe failed\n");
	480	break;
	481	}
	482	close(pipefd[1]);
	483	close(pipefd[0]);
	484	}
	485	}
	486
	487	static void fs_something(void)
	488	{
	489	const char *test_file_name = "temp-perf-code-reading-test-file--";
	490	FILE *f;
	491	int i;
	492
	493	for (i = 0; i < 1000; i++) {
	494	f = fopen(test_file_name, "w+");
	495	if (f) {
	496	fclose(f);
	497	unlink(test_file_name);
	498	}
	499	}
	500	}
	501
	502	#ifdef __s390x__
	503	#include "header.h" // for get_cpuid()
	504	#endif
	505
	506	static const char *do_determine_event(bool excl_kernel)
	507	{
	508	const char *event = excl_kernel ? "cycles:u" : "cycles";
	509
	510	#ifdef __s390x__
	511	char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
	512	unsigned int family;
	513	int ret, cpum_cf_a;
	514
	515	if (get_cpuid(cpuid, sizeof(cpuid)))
	516	goto out_clocks;
	517	ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
	518	model, cpum_cf_v, &cpum_cf_a);
	519	if (ret != 5) /* Not available */
	520	goto out_clocks;
	521	if (excl_kernel && (cpum_cf_a & 4))
	522	return event;
	523	if (!excl_kernel && (cpum_cf_a & 2))
	524	return event;
	525
	526	/* Fall through: missing authorization */
	527	out_clocks:
	528	event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
	529
	530	#endif
	531	return event;
	532	}
	533
	534	static void do_something(void)
	535	{
	536	fs_something();
	537
	538	sort_something();
	539
	540	syscall_something();
	541	}
	542
	543	enum {
	544	TEST_CODE_READING_OK,
	545	TEST_CODE_READING_NO_VMLINUX,
	546	TEST_CODE_READING_NO_KCORE,
	547	TEST_CODE_READING_NO_ACCESS,
	548	TEST_CODE_READING_NO_KERNEL_OBJ,
	549	};
	550
	551	static int do_test_code_reading(bool try_kcore)
	552	{
	553	struct machine *machine;
	554	struct thread *thread;
	555	struct record_opts opts = {
	556	.mmap_pages = UINT_MAX,
	557	.user_freq = UINT_MAX,
	558	.user_interval = ULLONG_MAX,
	559	.freq = 500,
	560	.target = {
	561	.uses_mmap = true,
	562	},
	563	};
	564	struct state state = {
	565	.done_cnt = 0,
	566	};
	567	struct perf_thread_map *threads = NULL;
	568	struct perf_cpu_map *cpus = NULL;
	569	struct evlist *evlist = NULL;
	570	struct evsel *evsel = NULL;
	571	int err = -1, ret;
	572	pid_t pid;
	573	struct map *map;
	574	bool have_vmlinux, have_kcore, excl_kernel = false;
	575
	576	pid = getpid();
	577
	578	machine = machine__new_host();
	579	machine->env = &perf_env;
	580
	581	ret = machine__create_kernel_maps(machine);
	582	if (ret < 0) {
	583	pr_debug("machine__create_kernel_maps failed\n");
	584	goto out_err;
	585	}
	586
	587	/* Force the use of kallsyms instead of vmlinux to try kcore */
	588	if (try_kcore)
	589	symbol_conf.kallsyms_name = "/proc/kallsyms";
	590
	591	/* Load kernel map */
	592	map = machine__kernel_map(machine);
	593	ret = map__load(map);
	594	if (ret < 0) {
	595	pr_debug("map__load failed\n");
	596	goto out_err;
	597	}
	598	have_vmlinux = dso__is_vmlinux(map->dso);
	599	have_kcore = dso__is_kcore(map->dso);
	600
	601	/* 2nd time through we just try kcore */
	602	if (try_kcore && !have_kcore)
	603	return TEST_CODE_READING_NO_KCORE;
	604
	605	/* No point getting kernel events if there is no kernel object */
	606	if (!have_vmlinux && !have_kcore)
	607	excl_kernel = true;
	608
	609	threads = thread_map__new_by_tid(pid);
	610	if (!threads) {
	611	pr_debug("thread_map__new_by_tid failed\n");
	612	goto out_err;
	613	}
	614
	615	ret = perf_event__synthesize_thread_map(NULL, threads,
	616	perf_event__process, machine, false);
	617	if (ret < 0) {
	618	pr_debug("perf_event__synthesize_thread_map failed\n");
	619	goto out_err;
	620	}
	621
	622	thread = machine__findnew_thread(machine, pid, pid);
	623	if (!thread) {
	624	pr_debug("machine__findnew_thread failed\n");
	625	goto out_put;
	626	}
	627
	628	cpus = perf_cpu_map__new(NULL);
	629	if (!cpus) {
	630	pr_debug("perf_cpu_map__new failed\n");
	631	goto out_put;
	632	}
	633
	634	while (1) {
	635	const char *str;
	636
	637	evlist = evlist__new();
	638	if (!evlist) {
	639	pr_debug("perf_evlist__new failed\n");
	640	goto out_put;
	641	}
	642
	643	perf_evlist__set_maps(&evlist->core, cpus, threads);
	644
	645	str = do_determine_event(excl_kernel);
	646	pr_debug("Parsing event '%s'\n", str);
	647	ret = parse_events(evlist, str, NULL);
	648	if (ret < 0) {
	649	pr_debug("parse_events failed\n");
	650	goto out_put;
	651	}
	652
	653	perf_evlist__config(evlist, &opts, NULL);
	654
	655	evsel = evlist__first(evlist);
	656
	657	evsel->core.attr.comm = 1;
	658	evsel->core.attr.disabled = 1;
	659	evsel->core.attr.enable_on_exec = 0;
	660
	661	ret = evlist__open(evlist);
	662	if (ret < 0) {
	663	if (!excl_kernel) {
	664	excl_kernel = true;
	665	/*
	666	* Both cpus and threads are now owned by evlist
	667	* and will be freed by following perf_evlist__set_maps
	668	* call. Getting refference to keep them alive.
	669	*/
	670	perf_cpu_map__get(cpus);
	671	perf_thread_map__get(threads);
	672	perf_evlist__set_maps(&evlist->core, NULL, NULL);
	673	evlist__delete(evlist);
	674	evlist = NULL;
	675	continue;
	676	}
	677
	678	if (verbose > 0) {
	679	char errbuf[512];
	680	perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
	681	pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
	682	}
	683
	684	goto out_put;
	685	}
	686	break;
	687	}
	688
	689	ret = evlist__mmap(evlist, UINT_MAX);
	690	if (ret < 0) {
	691	pr_debug("evlist__mmap failed\n");
	692	goto out_put;
	693	}
	694
	695	evlist__enable(evlist);
	696
	697	do_something();
	698
	699	evlist__disable(evlist);
	700
	701	ret = process_events(machine, evlist, &state);
	702	if (ret < 0)
	703	goto out_put;
	704
	705	if (!have_vmlinux && !have_kcore && !try_kcore)
	706	err = TEST_CODE_READING_NO_KERNEL_OBJ;
	707	else if (!have_vmlinux && !try_kcore)
	708	err = TEST_CODE_READING_NO_VMLINUX;
	709	else if (excl_kernel)
	710	err = TEST_CODE_READING_NO_ACCESS;
	711	else
	712	err = TEST_CODE_READING_OK;
	713	out_put:
	714	thread__put(thread);
	715	out_err:
	716
	717	if (evlist) {
	718	evlist__delete(evlist);
	719	} else {
	720	perf_cpu_map__put(cpus);
	721	perf_thread_map__put(threads);
	722	}
	723	machine__delete_threads(machine);
	724	machine__delete(machine);
	725
	726	return err;
	727	}
	728
	729	int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused)
	730	{
	731	int ret;
	732
	733	ret = do_test_code_reading(false);
	734	if (!ret)
	735	ret = do_test_code_reading(true);
	736
	737	switch (ret) {
	738	case TEST_CODE_READING_OK:
	739	return 0;
	740	case TEST_CODE_READING_NO_VMLINUX:
	741	pr_debug("no vmlinux\n");
	742	return 0;
	743	case TEST_CODE_READING_NO_KCORE:
	744	pr_debug("no kcore\n");
	745	return 0;
	746	case TEST_CODE_READING_NO_ACCESS:
	747	pr_debug("no access\n");
	748	return 0;
	749	case TEST_CODE_READING_NO_KERNEL_OBJ:
	750	pr_debug("no kernel obj\n");
	751	return 0;
	752	default:
	753	return -1;
	754	};
	755	}