From: Masami Hiramatsu Date: Thu, 13 Aug 2009 20:34:21 +0000 (-0400) Subject: x86: X86 instruction decoder build-time selftest X-Git-Tag: v2.6.33-rc1~399^2~255 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=ca0e9badd1a39fecdd235f4bf1481b9da756e27b x86: X86 instruction decoder build-time selftest Add a user-space selftest of x86 instruction decoder at kernel build time. When CONFIG_X86_DECODER_SELFTEST=y, Kbuild builds a test harness of x86 instruction decoder and performs it after building vmlinux. The test compares the results of objdump and x86 instruction decoder code and check there are no differences. Signed-off-by: Masami Hiramatsu Signed-off-by: Jim Keniston Cc: Ananth N Mavinakayanahalli Cc: Avi Kivity Cc: Andi Kleen Cc: Christoph Hellwig Cc: Frank Ch. Eigler Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Jason Baron Cc: K.Prasad Cc: Lai Jiangshan Cc: Li Zefan Cc: Przemysław Pawełczyk Cc: Roland McGrath Cc: Sam Ravnborg Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: Tom Zanussi Cc: Vegard Nossum LKML-Reference: <20090813203421.31965.29006.stgit@localhost.localdomain> Signed-off-by: Frederic Weisbecker --- diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index d105f29bb6bb..7d0b681a132b 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -186,6 +186,15 @@ config X86_DS_SELFTEST config HAVE_MMIOTRACE_SUPPORT def_bool y +config X86_DECODER_SELFTEST + bool "x86 instruction decoder selftest" + depends on DEBUG_KERNEL + ---help--- + Perform x86 instruction decoder selftests at build time. + This option is useful for checking the sanity of x86 instruction + decoder code. + If unsure, say "N". + # # IO delay types: # diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 1b68659c41b4..5fe16bfd15ac 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -154,6 +154,9 @@ all: bzImage KBUILD_IMAGE := $(boot)/bzImage bzImage: vmlinux +ifeq ($(CONFIG_X86_DECODER_SELFTEST),y) + $(Q)$(MAKE) $(build)=arch/x86/tools posttest +endif $(Q)$(MAKE) $(build)=$(boot) $(KBUILD_IMAGE) $(Q)mkdir -p $(objtree)/arch/$(UTS_MACHINE)/boot $(Q)ln -fsn ../../x86/boot/bzImage $(objtree)/arch/$(UTS_MACHINE)/boot/$@ diff --git a/arch/x86/tools/Makefile b/arch/x86/tools/Makefile new file mode 100644 index 000000000000..3dd626b99dc8 --- /dev/null +++ b/arch/x86/tools/Makefile @@ -0,0 +1,15 @@ +PHONY += posttest +quiet_cmd_posttest = TEST $@ + cmd_posttest = $(OBJDUMP) -d $(objtree)/vmlinux | awk -f $(srctree)/arch/x86/tools/distill.awk | $(obj)/test_get_len + +posttest: $(obj)/test_get_len vmlinux + $(call cmd,posttest) + +hostprogs-y := test_get_len + +# -I needed for generated C source and C source which in the kernel tree. +HOSTCFLAGS_test_get_len.o := -Wall -I$(objtree)/arch/x86/lib/ -I$(srctree)/arch/x86/include/ -I$(srctree)/arch/x86/lib/ + +# Dependancies 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 $(objtree)/arch/x86/lib/inat-tables.c + diff --git a/arch/x86/tools/distill.awk b/arch/x86/tools/distill.awk new file mode 100644 index 000000000000..d433619bb866 --- /dev/null +++ b/arch/x86/tools/distill.awk @@ -0,0 +1,42 @@ +#!/bin/awk -f +# Usage: objdump -d a.out | awk -f distill.awk | ./test_get_len +# Distills the disassembly as follows: +# - Removes all lines except the disassembled instructions. +# - For instructions that exceed 1 line (7 bytes), crams all the hex bytes +# into a single line. +# - Remove bad(or prefix only) instructions + +BEGIN { + prev_addr = "" + prev_hex = "" + prev_mnemonic = "" + bad_expr = "(\\(bad\\)|^rex|^.byte|^rep(z|nz)$|^lock$|^es$|^cs$|^ss$|^ds$|^fs$|^gs$|^data(16|32)$|^addr(16|32|64))" + fwait_expr = "^9b " + fwait_str="9b\tfwait" +} + +/^ *[0-9a-f]+:/ { + if (split($0, field, "\t") < 3) { + # This is a continuation of the same insn. + prev_hex = prev_hex field[2] + } else { + # Skip bad instructions + if (match(prev_mnemonic, bad_expr)) + prev_addr = "" + # Split fwait from other f* instructions + if (match(prev_hex, fwait_expr) && prev_mnemonic != "fwait") { + printf "%s\t%s\n", prev_addr, fwait_str + sub(fwait_expr, "", prev_hex) + } + if (prev_addr != "") + printf "%s\t%s\t%s\n", prev_addr, prev_hex, prev_mnemonic + prev_addr = field[1] + prev_hex = field[2] + prev_mnemonic = field[3] + } +} + +END { + if (prev_addr != "") + printf "%s\t%s\t%s\n", prev_addr, prev_hex, prev_mnemonic +} diff --git a/arch/x86/tools/test_get_len.c b/arch/x86/tools/test_get_len.c new file mode 100644 index 000000000000..1e81adb2d8a9 --- /dev/null +++ b/arch/x86/tools/test_get_len.c @@ -0,0 +1,113 @@ +/* + * 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 + */ + +#include +#include +#include +#include + +#ifdef __x86_64__ +#define CONFIG_X86_64 +#else +#define CONFIG_X86_32 +#endif +#define unlikely(cond) (cond) + +#include +#include +#include + +/* + * Test of instruction analysis in general and insn_get_length() in + * particular. See if insn_get_length() and the disassembler agree + * on the length of each instruction in an elf disassembly. + * + * Usage: objdump -d a.out | awk -f distill.awk | ./test_get_len + */ + +const char *prog; + +static void usage(void) +{ + fprintf(stderr, "Usage: objdump -d a.out | awk -f distill.awk |" + " ./test_get_len\n"); + exit(1); +} + +static void malformed_line(const char *line, int line_nr) +{ + fprintf(stderr, "%s: malformed line %d:\n%s", prog, line_nr, line); + exit(3); +} + +#define BUFSIZE 256 + +int main(int argc, char **argv) +{ + char line[BUFSIZE]; + unsigned char insn_buf[16]; + struct insn insn; + int insns = 0; + + prog = argv[0]; + if (argc > 1) + usage(); + + while (fgets(line, BUFSIZE, stdin)) { + char copy[BUFSIZE], *s, *tab1, *tab2; + int nb = 0; + unsigned int b; + + insns++; + memset(insn_buf, 0, 16); + strcpy(copy, line); + tab1 = strchr(copy, '\t'); + if (!tab1) + malformed_line(line, insns); + s = tab1 + 1; + s += strspn(s, " "); + tab2 = strchr(s, '\t'); + if (!tab2) + malformed_line(line, insns); + *tab2 = '\0'; /* Characters beyond tab2 aren't examined */ + while (s < tab2) { + if (sscanf(s, "%x", &b) == 1) { + insn_buf[nb++] = (unsigned char) b; + s += 3; + } else + break; + } + /* Decode an instruction */ +#ifdef __x86_64__ + insn_init(&insn, insn_buf, 1); +#else + insn_init(&insn, insn_buf, 0); +#endif + insn_get_length(&insn); + if (insn.length != nb) { + fprintf(stderr, "Error: %s", line); + fprintf(stderr, "Error: objdump says %d bytes, but " + "insn_get_length() says %d (attr:%x)\n", nb, + insn.length, insn.attr); + exit(2); + } + } + fprintf(stderr, "Succeed: decoded and checked %d instructions\n", + insns); + return 0; +}