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perf tests: objdump output can contain multi byte chunks

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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: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Adrian 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jan Stancek 2016-01-12 11:07:44 +01:00 committed by Arnaldo Carvalho de Melo
parent b6f35ed774
commit b2d0dbf097
1 changed files with 71 additions and 29 deletions
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100
tools/perf/tests/code-reading.c
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@ -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)
{
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 i, j = 0;
size_t ret, bytes_read = 0;
/* Skip to a colon */
p = strchr(line, ':');
if (!p)
return 0;
i = p + 1 - line;
p++;
/* Read bytes */
while (j < len) {
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]))
/* Skip initial spaces */
while (*p) {
if (!isspace(*p))
break;
c1 = line[i++];
if (i >= line_len || !isxdigit(line[i]))
break;
c2 = line[i++];
/* Followed by a space */
if (i < line_len && line[i] && !isspace(line[i]))
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;
}