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x86, perf: Add a build-time sanity test to the x86 decoder

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Add a sanity test of x86 insn decoder against a stream
of randomly generated input, at build time.

This test is also able to reproduce any bug that might
trigger by allowing the passing of random-seed and
iteration-number to the test, or by passing input
which has invalid byte code.

Changes in V2:
 - Code cleanup.
 - Show how to reproduce the error by insn_sanity test.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: acme@redhat.com
Cc: ming.m.lin@intel.com
Cc: robert.richter@amd.com
Cc: ravitillo@lbl.gov
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20111020140109.20938.92572.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Masami Hiramatsu 2011-10-20 23:01:09 +09:00 committed by Ingo Molnar
parent 19e0bafc36
commit 1ec454baf1
3 changed files with 291 additions and 1 deletions
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7
arch/x86/include/asm/insn.h
View File

@ -137,6 +137,13 @@ static inline int insn_is_avx(struct insn *insn)
return (insn->vex_prefix.value != 0);
}
/* Ensure this instruction is decoded completely */
static inline int insn_complete(struct insn *insn)
{
return insn->opcode.got && insn->modrm.got && insn->sib.got &&
insn->displacement.got && insn->immediate.got;
}
static inline insn_byte_t insn_vex_m_bits(struct insn *insn)
{
if (insn->vex_prefix.nbytes == 2) /* 2 bytes VEX */

10
arch/x86/tools/Makefile
View File

@ -18,14 +18,22 @@ chkobjdump = $(srctree)/arch/x86/tools/chkobjdump.awk
quiet_cmd_posttest = TEST $@
cmd_posttest = ($(OBJDUMP) -v | $(AWK) -f $(chkobjdump)) || $(OBJDUMP) -d -j .text $(objtree)/vmlinux | $(AWK) -f $(distill_awk) | $(obj)/test_get_len $(posttest_64bit) $(posttest_verbose)
posttest: $(obj)/test_get_len vmlinux
quiet_cmd_sanitytest = TEST $@
cmd_sanitytest = $(obj)/insn_sanity $(posttest_64bit) -m 1000000
posttest: $(obj)/test_get_len vmlinux $(obj)/insn_sanity
$(call cmd,posttest)
$(call cmd,sanitytest)
hostprogs-y := test_get_len
hostprogs-y := insn_sanity
# -I needed for generated C source and C source which in the kernel tree.
HOSTCFLAGS_test_get_len.o := -Wall -I$(objtree)/arch/x86/lib/ -I$(srctree)/arch/x86/include/ -I$(srctree)/arch/x86/lib/ -I$(srctree)/include/
HOSTCFLAGS_insn_sanity.o := -Wall -I$(objtree)/arch/x86/lib/ -I$(srctree)/arch/x86/include/ -I$(srctree)/arch/x86/lib/ -I$(srctree)/include/
# Dependencies are also needed.
$(obj)/test_get_len.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/inat.c $(srctree)/arch/x86/include/asm/inat_types.h $(srctree)/arch/x86/include/asm/inat.h $(srctree)/arch/x86/include/asm/insn.h $(objtree)/arch/x86/lib/inat-tables.c
$(obj)/insn_sanity.o: $(srctree)/arch/x86/lib/insn.c $(srctree)/arch/x86/lib/inat.c $(srctree)/arch/x86/include/asm/inat_types.h $(srctree)/arch/x86/include/asm/inat.h $(srctree)/arch/x86/include/asm/insn.h $(objtree)/arch/x86/lib/inat-tables.c

275
arch/x86/tools/insn_sanity.c Normal file
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@ -0,0 +1,275 @@
/*
* x86 decoder sanity test - based on test_get_insn.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2009
* Copyright (C) Hitachi, Ltd., 2011
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define unlikely(cond) (cond)
#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))
#include <asm/insn.h>
#include <inat.c>
#include <insn.c>
/*
* Test of instruction analysis against tampering.
* Feed random binary to instruction decoder and ensure not to
* access out-of-instruction-buffer.
*/
#define DEFAULT_MAX_ITER 10000
#define INSN_NOP 0x90
static const char *prog; /* Program name */
static int verbose; /* Verbosity */
static int x86_64; /* x86-64 bit mode flag */
static unsigned int seed; /* Random seed */
static unsigned long iter_start; /* Start of iteration number */
static unsigned long iter_end = DEFAULT_MAX_ITER; /* End of iteration number */
static FILE *input_file; /* Input file name */
static void usage(const char *err)
{
if (err)
fprintf(stderr, "Error: %s\n\n", err);
fprintf(stderr, "Usage: %s [-y|-n|-v] [-s seed[,no]] [-m max] [-i input]\n", prog);
fprintf(stderr, "\t-y 64bit mode\n");
fprintf(stderr, "\t-n 32bit mode\n");
fprintf(stderr, "\t-v Verbose mode\n");
fprintf(stderr, "\t-s Give a random seed (and iteration number)\n");
fprintf(stderr, "\t-m Give a maximum iteration number\n");
fprintf(stderr, "\t-i Give an input file with decoded binary\n");
exit(1);
}
static void dump_field(FILE *fp, const char *name, const char *indent,
struct insn_field *field)
{
fprintf(fp, "%s.%s = {\n", indent, name);
fprintf(fp, "%s\t.value = %d, bytes[] = {%x, %x, %x, %x},\n",
indent, field->value, field->bytes[0], field->bytes[1],
field->bytes[2], field->bytes[3]);
fprintf(fp, "%s\t.got = %d, .nbytes = %d},\n", indent,
field->got, field->nbytes);
}
static void dump_insn(FILE *fp, struct insn *insn)
{
fprintf(fp, "Instruction = {\n");
dump_field(fp, "prefixes", "\t", &insn->prefixes);
dump_field(fp, "rex_prefix", "\t", &insn->rex_prefix);
dump_field(fp, "vex_prefix", "\t", &insn->vex_prefix);
dump_field(fp, "opcode", "\t", &insn->opcode);
dump_field(fp, "modrm", "\t", &insn->modrm);
dump_field(fp, "sib", "\t", &insn->sib);
dump_field(fp, "displacement", "\t", &insn->displacement);
dump_field(fp, "immediate1", "\t", &insn->immediate1);
dump_field(fp, "immediate2", "\t", &insn->immediate2);
fprintf(fp, "\t.attr = %x, .opnd_bytes = %d, .addr_bytes = %d,\n",
insn->attr, insn->opnd_bytes, insn->addr_bytes);
fprintf(fp, "\t.length = %d, .x86_64 = %d, .kaddr = %p}\n",
insn->length, insn->x86_64, insn->kaddr);
}
static void dump_stream(FILE *fp, const char *msg, unsigned long nr_iter,
unsigned char *insn_buf, struct insn *insn)
{
int i;
fprintf(fp, "%s:\n", msg);
dump_insn(stderr, insn);
fprintf(fp, "You can reproduce this with below command(s);\n");
/* Input a decoded instruction sequence directly */
fprintf(fp, " $ echo ");
for (i = 0; i < MAX_INSN_SIZE; i++)
fprintf(fp, " %02x", insn_buf[i]);
fprintf(fp, " | %s -i -\n", prog);
if (!input_file) {
fprintf(fp, "Or \n");
/* Give a seed and iteration number */
fprintf(fp, " $ %s -s 0x%x,%lu\n", prog, seed, nr_iter);
}
}
static void init_random_seed(void)
{
int fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0)
goto fail;
if (read(fd, &seed, sizeof(seed)) != sizeof(seed))
goto fail;
close(fd);
return;
fail:
usage("Failed to open /dev/urandom");
}
/* Read given instruction sequence from the input file */
static int read_next_insn(unsigned char *insn_buf)
{
char buf[256] = "", *tmp;
int i;
tmp = fgets(buf, ARRAY_SIZE(buf), input_file);
if (tmp == NULL || feof(input_file))
return 0;
for (i = 0; i < MAX_INSN_SIZE; i++) {
insn_buf[i] = (unsigned char)strtoul(tmp, &tmp, 16);
if (*tmp != ' ')
break;
}
return i;
}
static int generate_insn(unsigned char *insn_buf)
{
int i;
if (input_file)
return read_next_insn(insn_buf);
/* Fills buffer with random binary up to MAX_INSN_SIZE */
for (i = 0; i < MAX_INSN_SIZE - 1; i += 2)
*(unsigned short *)(&insn_buf[i]) = random() & 0xffff;
while (i < MAX_INSN_SIZE)
insn_buf[i++] = random() & 0xff;
return i;
}
static void parse_args(int argc, char **argv)
{
int c;
char *tmp = NULL;
int set_seed = 0;
prog = argv[0];
while ((c = getopt(argc, argv, "ynvs:m:i:")) != -1) {
switch (c) {
case 'y':
x86_64 = 1;
break;
case 'n':
x86_64 = 0;
break;
case 'v':
verbose = 1;
break;
case 'i':
if (strcmp("-", optarg) == 0)
input_file = stdin;
else
input_file = fopen(optarg, "r");
if (!input_file)
usage("Failed to open input file");
break;
case 's':
seed = (unsigned int)strtoul(optarg, &tmp, 0);
if (*tmp == ',') {
optarg = tmp + 1;
iter_start = strtoul(optarg, &tmp, 0);
}
if (*tmp != '\0' || tmp == optarg)
usage("Failed to parse seed");
set_seed = 1;
break;
case 'm':
iter_end = strtoul(optarg, &tmp, 0);
if (*tmp != '\0' || tmp == optarg)
usage("Failed to parse max_iter");
break;
default:
usage(NULL);
}
}
/* Check errors */
if (iter_end < iter_start)
usage("Max iteration number must be bigger than iter-num");
if (set_seed && input_file)
usage("Don't use input file (-i) with random seed (-s)");
/* Initialize random seed */
if (!input_file) {
if (!set_seed) /* No seed is given */
init_random_seed();
srand(seed);
}
}
int main(int argc, char **argv)
{
struct insn insn;
int insns = 0;
int errors = 0;
unsigned long i;
unsigned char insn_buf[MAX_INSN_SIZE * 2];
parse_args(argc, argv);
/* Prepare stop bytes with NOPs */
memset(insn_buf + MAX_INSN_SIZE, INSN_NOP, MAX_INSN_SIZE);
for (i = 0; i < iter_end; i++) {
if (generate_insn(insn_buf) <= 0)
break;
if (i < iter_start) /* Skip to given iteration number */
continue;
/* Decode an instruction */
insn_init(&insn, insn_buf, x86_64);
insn_get_length(&insn);
if (verbose && !insn_complete(&insn))
dump_stream(stdout, "Info: Found an undecodable input", i, insn_buf, &insn);
if (insn.next_byte <= insn.kaddr ||
insn.kaddr + MAX_INSN_SIZE < insn.next_byte) {
/* Access out-of-range memory */
dump_stream(stdout, "Error: Found an access violation", i, insn_buf, &insn);
errors++;
}
insns++;
}
fprintf(stdout, "%s: decoded and checked %d %s instructions with %d errors (seed:0x%x)\n", (errors) ? "Failure" : "Success", insns, (input_file) ? "given" : "random", errors, seed);
return errors ? 1 : 0;
}