Commit b2d0dbf0 authored by Jan Stancek's avatar Jan Stancek Committed by Arnaldo Carvalho de Melo
Browse files

perf tests: objdump output can contain multi byte chunks 



objdump's raw insn output can vary across architectures on the number of
bytes per chunk (bpc) displayed and their endianness.

The code-reading test relied on reading objdump output as 1 bpc. Kaixu
Xia reported test failure on ARM64, where objdump displays 4 bpc:

  70c48:        f90027bf         str        xzr, [x29,#72]
  70c4c:        91224000         add        x0, x0, #0x890
  70c50:        f90023a0         str        x0, [x29,#64]

This patch adds support to read raw insn output for any bpc length.
In case of 2+ bpc it also guesses objdump's display endian.

Reported-and-Tested-by: default avatarKaixu Xia <xiakaixu@huawei.com>
Signed-off-by: default avatarJan Stancek <jstancek@redhat.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/07f0f7bcbda78deb423298708ef9b6a54d6b92bd.1452592712.git.jstancek@redhat.com


[ Fix up pr_fmt() call to use %zd for size_t variables, fixing the build on Ubuntu cross-compiling to armhf and ppc64 ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent b6f35ed7

tools/perf/tests/code-reading.c

+71 −29
Original line number Diff line number Diff line
@@ -33,44 +33,86 @@ static unsigned int hex(char c) 
	return c - 'A' + 10;

}



static size_t read_objdump_line(const char *line, size_t line_len, void *buf,

			      size_t len)

static size_t read_objdump_chunk(const char **line, unsigned char **buf,

				 size_t *buf_len)

{

	const char *p;

	size_t i, j = 0;



	/* Skip to a colon */

	p = strchr(line, ':');

	if (!p)

		return 0;

	i = p + 1 - line;

	size_t bytes_read = 0;

	unsigned char *chunk_start = *buf;



	/* Read bytes */

	while (j < len) {

	while (*buf_len > 0) {

		char c1, c2;



		/* Skip spaces */

		for (; i < line_len; i++) {

			if (!isspace(line[i]))

				break;

		}

		/* Get 2 hex digits */

		if (i >= line_len || !isxdigit(line[i]))

		c1 = *(*line)++;

		if (!isxdigit(c1))

			break;

		c2 = *(*line)++;

		if (!isxdigit(c2))

			break;

		c1 = line[i++];

		if (i >= line_len || !isxdigit(line[i]))



		/* Store byte and advance buf */

		**buf = (hex(c1) << 4) | hex(c2);

		(*buf)++;

		(*buf_len)--;

		bytes_read++;



		/* End of chunk? */

		if (isspace(**line))

			break;

		c2 = line[i++];

		/* Followed by a space */

		if (i < line_len && line[i] && !isspace(line[i]))

	}



	/*

	 * 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;

		/* Store byte */

		*(unsigned char *)buf = (hex(c1) << 4) | hex(c2);

		buf += 1;

		j++;

		p++;

	}



	do {

		ret = read_objdump_chunk(&p, &buf, &buf_len);

		bytes_read += ret;

		p++;

	} while (ret > 0);



	/* return number of successfully read bytes */

	return j;

	return bytes_read;

}



static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
@@ -95,7 +137,7 @@ static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) 
		}



		/* read objdump data into temporary buffer */

		read_bytes = read_objdump_line(line, ret, tmp, sizeof(tmp));

		read_bytes = read_objdump_line(line, tmp, sizeof(tmp));

		if (!read_bytes)

			continue;
@@ -152,7 +194,7 @@ static int read_via_objdump(const char *filename, u64 addr, void *buf, 


	ret = read_objdump_output(f, buf, &len, addr);

	if (len) {

		pr_debug("objdump read too few bytes\n");

		pr_debug("objdump read too few bytes: %zd\n", len);

		if (!ret)

			ret = len;

	}

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