From 1ec454baf1245df4fdb5dae728da3363630ce6de Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 20 Oct 2011 23:01:09 +0900 Subject: [PATCH] x86, perf: Add a build-time sanity test to the x86 decoder 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 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 Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Andi Kleen Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20111020140109.20938.92572.stgit@localhost.localdomain Signed-off-by: Ingo Molnar --- arch/x86/include/asm/insn.h | 7 + arch/x86/tools/Makefile | 10 +- arch/x86/tools/insn_sanity.c | 275 +++++++++++++++++++++++++++++++++++ 3 files changed, 291 insertions(+), 1 deletion(-) create mode 100644 arch/x86/tools/insn_sanity.c diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h index 88c765e16410..74df3f1eddfd 100644 --- a/arch/x86/include/asm/insn.h +++ b/arch/x86/include/asm/insn.h @@ -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 */ diff --git a/arch/x86/tools/Makefile b/arch/x86/tools/Makefile index f82082677337..3255c3df67f4 100644 --- a/arch/x86/tools/Makefile +++ b/arch/x86/tools/Makefile @@ -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 diff --git a/arch/x86/tools/insn_sanity.c b/arch/x86/tools/insn_sanity.c new file mode 100644 index 000000000000..334d9de7d0ca --- /dev/null +++ b/arch/x86/tools/insn_sanity.c @@ -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 +#include +#include +#include +#include +#include +#include +#include + +#define unlikely(cond) (cond) +#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0])) + +#include +#include +#include + +/* + * 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; +} -- 2.34.1