x86, perf: Add a build-time sanity test to the x86 decoder (1ec454ba) · Commits · 戴 / test

arch/x86/include/asm/insn.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -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 */

arch/x86/tools/Makefile

+9 −1

Original line number	Diff line number	Diff line
		@@ -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

arch/x86/tools/insn_sanity.c

0 → 100644

+275 −0

Original line number	Diff line number	Diff line
		/*
		* 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;
		}

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