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Re: [Qemu-devel] [PATCH v4 4/9] disas: Support the Capstone disassembler
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v4 4/9] disas: Support the Capstone disassembler library |
Date: |
Mon, 02 Oct 2017 15:40:36 +0100 |
User-agent: |
mu4e 0.9.19; emacs 26.0.60 |
Richard Henderson <address@hidden> writes:
> If configured, prefer this over our rather dated copy of the
> GPLv2-only binutils. This will be especially apparent with
> the proposed vector extensions to TCG, as disas/i386.c does
> not handle AVX.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> include/disas/bfd.h | 4 +
> include/disas/capstone.h | 38 ++++++++
> disas.c | 219
> ++++++++++++++++++++++++++++++++++++++++++++---
> configure | 26 ++++++
> 4 files changed, 274 insertions(+), 13 deletions(-)
> create mode 100644 include/disas/capstone.h
>
> diff --git a/include/disas/bfd.h b/include/disas/bfd.h
> index b01e002b4c..0f4ecdeb88 100644
> --- a/include/disas/bfd.h
> +++ b/include/disas/bfd.h
> @@ -377,6 +377,10 @@ typedef struct disassemble_info {
> /* Command line options specific to the target disassembler. */
> char * disassembler_options;
>
> + /* Options for Capstone disassembly. */
> + int cap_arch;
> + int cap_mode;
> +
> } disassemble_info;
>
>
> diff --git a/include/disas/capstone.h b/include/disas/capstone.h
> new file mode 100644
> index 0000000000..84e214956d
> --- /dev/null
> +++ b/include/disas/capstone.h
> @@ -0,0 +1,38 @@
> +#ifndef QEMU_CAPSTONE_H
> +#define QEMU_CAPSTONE_H 1
> +
> +#ifdef CONFIG_CAPSTONE
> +
> +#include <capstone.h>
> +
> +#else
> +
> +/* Just enough to allow backends to init without ifdefs. */
> +
> +#define CS_ARCH_ARM -1
> +#define CS_ARCH_ARM64 -1
> +#define CS_ARCH_MIPS -1
> +#define CS_ARCH_X86 -1
> +#define CS_ARCH_PPC -1
> +#define CS_ARCH_SPARC -1
> +#define CS_ARCH_SYSZ -1
> +
> +#define CS_MODE_LITTLE_ENDIAN 0
> +#define CS_MODE_BIG_ENDIAN 0
> +#define CS_MODE_ARM 0
> +#define CS_MODE_16 0
> +#define CS_MODE_32 0
> +#define CS_MODE_64 0
> +#define CS_MODE_THUMB 0
> +#define CS_MODE_MCLASS 0
> +#define CS_MODE_V8 0
> +#define CS_MODE_MICRO 0
> +#define CS_MODE_MIPS3 0
> +#define CS_MODE_MIPS32R6 0
> +#define CS_MODE_MIPSGP64 0
> +#define CS_MODE_V9 0
> +#define CS_MODE_MIPS32 0
> +#define CS_MODE_MIPS64 0
> +
> +#endif /* CONFIG_CAPSTONE */
> +#endif /* QEMU_CAPSTONE_H */
> diff --git a/disas.c b/disas.c
> index ad675dc361..746d76c07d 100644
> --- a/disas.c
> +++ b/disas.c
> @@ -6,6 +6,7 @@
>
> #include "cpu.h"
> #include "disas/disas.h"
> +#include "disas/capstone.h"
>
> typedef struct CPUDebug {
> struct disassemble_info info;
> @@ -171,6 +172,192 @@ static int print_insn_od_target(bfd_vma pc,
> disassemble_info *info)
> return print_insn_objdump(pc, info, "OBJD-T");
> }
>
> +#ifdef CONFIG_CAPSTONE
> +/* Temporary storage for the capstone library. This will be alloced via
> + malloc with a size private to the library; thus there's no reason not
> + to share this across calls and across host vs target disassembly. */
> +static __thread cs_insn *cap_insn;
> +
> +/* Initialize the Capstone library. */
> +/* ??? It would be nice to cache this. We would need one handle for the
> + host and one for the target. For most targets we can reset specific
> + parameters via cs_option(CS_OPT_MODE, new_mode), but we cannot change
> + CS_ARCH_* in this way. Thus we would need to be able to close and
> + re-open the target handle with a different arch for the target in order
> + to handle AArch64 vs AArch32 mode switching. */
> +static cs_err cap_disas_start(disassemble_info *info, csh *handle)
> +{
> + cs_mode cap_mode = info->cap_mode;
> + cs_err err;
> +
> + cap_mode += (info->endian == BFD_ENDIAN_BIG ? CS_MODE_BIG_ENDIAN
> + : CS_MODE_LITTLE_ENDIAN);
> +
> + err = cs_open(info->cap_arch, cap_mode, handle);
> + if (err != CS_ERR_OK) {
> + return err;
> + }
> +
> + /* ??? There probably ought to be a better place to put this. */
> + if (info->cap_arch == CS_ARCH_X86) {
> + /* We don't care about errors (if for some reason the library
> + is compiled without AT&T syntax); the user will just have
> + to deal with the Intel syntax. */
> + cs_option(*handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_ATT);
> + }
> +
> + /* "Disassemble" unknown insns as ".byte W,X,Y,Z". */
> + cs_option(*handle, CS_OPT_SKIPDATA, CS_OPT_ON);
> +
> + /* Allocate temp space for cs_disasm_iter. */
> + if (cap_insn == NULL) {
> + cap_insn = cs_malloc(*handle);
> + if (cap_insn == NULL) {
if (!cap_insn)?
> + cs_close(handle);
> + return CS_ERR_MEM;
> + }
> + }
> + return CS_ERR_OK;
> +}
> +
> +/* Disassemble SIZE bytes at PC for the target. */
> +static bool cap_disas_target(disassemble_info *info, uint64_t pc, size_t
> size)
> +{
> + uint8_t cap_buf[1024];
> + csh handle;
> + cs_insn *insn;
> + size_t csize = 0;
> +
> + if (cap_disas_start(info, &handle) != CS_ERR_OK) {
> + return false;
> + }
> + insn = cap_insn;
> +
> + while (1) {
> + size_t tsize = MIN(sizeof(cap_buf) - csize, size);
> + const uint8_t *cbuf = cap_buf;
> +
> + target_read_memory(pc + csize, cap_buf + csize, tsize, info);
> + csize += tsize;
> + size -= tsize;
> +
> + while (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
> + (*info->fprintf_func)(info->stream,
> + "0x%08" PRIx64 ": %-12s %s\n",
> + insn->address, insn->mnemonic,
> + insn->op_str);
> + }
> +
> + /* If the target memory is not consumed, go back for more... */
> + if (size != 0) {
> + /* ... taking care to move any remaining fractional insn
> + to the beginning of the buffer. */
> + if (csize != 0) {
Given we are moving stuff and both size/csize are of size_t wouldn't if
(size > 0) be clearer here?
> + memmove(cap_buf, cbuf, csize);
> + }
> + continue;
> + }
> +
> + /* Since the target memory is consumed, we should not have
> + a remaining fractional insn. */
> + if (csize != 0) {
And here
> + (*info->fprintf_func)(info->stream,
> + "Disassembler disagrees with translator "
> + "over instruction decoding\n"
> + "Please report this to address@hidden");
> + }
> + break;
> + }
> +
> + cs_close(&handle);
> + return true;
> +}
> +
> +/* Disassemble SIZE bytes at CODE for the host. */
> +static bool cap_disas_host(disassemble_info *info, void *code, size_t size)
> +{
> + csh handle;
> + const uint8_t *cbuf;
> + cs_insn *insn;
> + uint64_t pc;
> +
> + if (cap_disas_start(info, &handle) != CS_ERR_OK) {
> + return false;
> + }
> + insn = cap_insn;
> +
> + cbuf = code;
> + pc = (uintptr_t)code;
> +
> + while (cs_disasm_iter(handle, &cbuf, &size, &pc, insn)) {
> + (*info->fprintf_func)(info->stream,
> + "0x%08" PRIx64 ": %-12s %s\n",
> + insn->address, insn->mnemonic,
> + insn->op_str);
> + }
> + if (size != 0) {
> + (*info->fprintf_func)(info->stream,
> + "Disassembler disagrees with TCG over instruction encoding\n"
> + "Please report this to address@hidden");
> + }
> +
> + cs_close(&handle);
> + return true;
> +}
> +
> +#if !defined(CONFIG_USER_ONLY)
> +/* Disassemble COUNT insns at PC for the target. */
> +static bool cap_disas_monitor(disassemble_info *info, uint64_t pc, int count)
> +{
> + uint8_t cap_buf[32];
> + csh handle;
> + cs_insn *insn;
> + size_t csize = 0;
> +
> + if (cap_disas_start(info, &handle) != CS_ERR_OK) {
> + return false;
> + }
> + insn = cap_insn;
> +
> + while (1) {
> + /* We want to read memory for one insn, but generically we do not
> + know how much memory that is. We have a small buffer which is
> + known to be sufficient for all supported targets. Try to not
> + read beyond the page, Just In Case. For even more simplicity,
> + ignore the actual target page size and use a 1k boundary. If
> + that turns out to be insufficient, we'll come back around the
> + loop and read more. */
> + uint64_t epc = QEMU_ALIGN_UP(pc + csize + 1, 1024);
> + size_t tsize = MIN(sizeof(cap_buf) - csize, epc - pc);
> + const uint8_t *cbuf = cap_buf;
> +
> + /* Make certain that we can make progress. */
> + assert(tsize != 0);
> + info->read_memory_func(pc, cap_buf + csize, tsize, info);
> + csize += tsize;
> +
> + if (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
> + (*info->fprintf_func)(info->stream,
> + "0x%08" PRIx64 ": %-12s %s\n",
> + insn->address, insn->mnemonic,
> + insn->op_str);
> + if (--count <= 0) {
> + break;
> + }
> + }
> + memmove(cap_buf, cbuf, csize);
> + }
> +
> + cs_close(&handle);
> + return true;
> +}
> +#endif /* !CONFIG_USER_ONLY */
> +#else
> +# define cap_disas_target(i, p, s) false
> +# define cap_disas_host(i, p, s) false
> +# define cap_disas_monitor(i, p, c) false
> +#endif /* CONFIG_CAPSTONE */
> +
> /* Disassemble this for me please... (debugging). */
> void target_disas(FILE *out, CPUState *cpu, target_ulong code,
> target_ulong size)
> @@ -188,6 +375,8 @@ void target_disas(FILE *out, CPUState *cpu, target_ulong
> code,
> s.info.buffer_vma = code;
> s.info.buffer_length = size;
> s.info.print_address_func = generic_print_address;
> + s.info.cap_arch = -1;
> + s.info.cap_mode = 0;
>
> #ifdef TARGET_WORDS_BIGENDIAN
> s.info.endian = BFD_ENDIAN_BIG;
> @@ -199,6 +388,10 @@ void target_disas(FILE *out, CPUState *cpu, target_ulong
> code,
> cc->disas_set_info(cpu, &s.info);
> }
>
> + if (s.info.cap_arch >= 0 && cap_disas_target(&s.info, code, size)) {
> + return;
> + }
> +
> if (s.info.print_insn == NULL) {
> s.info.print_insn = print_insn_od_target;
> }
> @@ -206,18 +399,6 @@ void target_disas(FILE *out, CPUState *cpu, target_ulong
> code,
> for (pc = code; size > 0; pc += count, size -= count) {
> fprintf(out, "0x" TARGET_FMT_lx ": ", pc);
> count = s.info.print_insn(pc, &s.info);
> -#if 0
> - {
> - int i;
> - uint8_t b;
> - fprintf(out, " {");
> - for(i = 0; i < count; i++) {
> - target_read_memory(pc + i, &b, 1, &s.info);
> - fprintf(out, " %02x", b);
> - }
> - fprintf(out, " }");
> - }
> -#endif
> fprintf(out, "\n");
> if (count < 0)
> break;
> @@ -245,6 +426,8 @@ void disas(FILE *out, void *code, unsigned long size)
> s.info.buffer = code;
> s.info.buffer_vma = (uintptr_t)code;
> s.info.buffer_length = size;
> + s.info.cap_arch = -1;
> + s.info.cap_mode = 0;
>
> #ifdef HOST_WORDS_BIGENDIAN
> s.info.endian = BFD_ENDIAN_BIG;
> @@ -282,6 +465,11 @@ void disas(FILE *out, void *code, unsigned long size)
> #elif defined(__hppa__)
> print_insn = print_insn_hppa;
> #endif
> +
> + if (s.info.cap_arch >= 0 && cap_disas_host(&s.info, code, size)) {
> + return;
> + }
> +
> if (print_insn == NULL) {
> print_insn = print_insn_od_host;
> }
> @@ -344,8 +532,9 @@ void monitor_disas(Monitor *mon, CPUState *cpu,
> monitor_disas_is_physical = is_physical;
> s.info.read_memory_func = monitor_read_memory;
> s.info.print_address_func = generic_print_address;
> -
> s.info.buffer_vma = pc;
> + s.info.cap_arch = -1;
> + s.info.cap_mode = 0;
>
> #ifdef TARGET_WORDS_BIGENDIAN
> s.info.endian = BFD_ENDIAN_BIG;
> @@ -357,6 +546,10 @@ void monitor_disas(Monitor *mon, CPUState *cpu,
> cc->disas_set_info(cpu, &s.info);
> }
>
> + if (s.info.cap_arch >= 0 && cap_disas_monitor(&s.info, pc, nb_insn)) {
> + return;
> + }
> +
> if (!s.info.print_insn) {
> monitor_printf(mon, "0x" TARGET_FMT_lx
> ": Asm output not supported on this arch\n", pc);
> diff --git a/configure b/configure
> index 6587e8014b..3777db91b6 100755
> --- a/configure
> +++ b/configure
> @@ -367,6 +367,7 @@ opengl_dmabuf="no"
> cpuid_h="no"
> avx2_opt="no"
> zlib="yes"
> +capstone=""
> lzo=""
> snappy=""
> bzip2=""
> @@ -1286,6 +1287,10 @@ for opt do
> error_exit "vhost-user isn't available on win32"
> fi
> ;;
> + --disable-capstone) capstone="no"
> + ;;
> + --enable-capstone) capstone="yes"
> + ;;
> *)
> echo "ERROR: unknown option $opt"
> echo "Try '$0 --help' for more information"
> @@ -1533,6 +1538,7 @@ disabled with --disable-FEATURE, default is enabled if
> available:
> vxhs Veritas HyperScale vDisk backend support
> crypto-afalg Linux AF_ALG crypto backend driver
> vhost-user vhost-user support
> + capstone capstone disassembler support
>
> NOTE: The object files are built at the place where configure is launched
> EOF
> @@ -4371,6 +4377,22 @@ EOF
> fi
>
> ##########################################
> +# capstone
> +
> +if test "$capstone" != no; then
> + if $pkg_config capstone; then
> + capstone=yes
> + QEMU_CFLAGS="$QEMU_CFLAGS $($pkg_config --cflags capstone)"
> + LIBS="$($pkg_config --libs capstone) $LIBS"
> + else
> + if test "$capstone" = yes; then
> + feature_not_found capstone
> + fi
> + capstone=no
> + fi
> +fi
> +
> +##########################################
> # check if we have fdatasync
>
> fdatasync=no
> @@ -5423,6 +5445,7 @@ echo "jemalloc support $jemalloc"
> echo "avx2 optimization $avx2_opt"
> echo "replication support $replication"
> echo "VxHS block device $vxhs"
> +echo "capstone $capstone"
>
> if test "$sdl_too_old" = "yes"; then
> echo "-> Your SDL version is too old - please upgrade to have SDL support"
> @@ -6088,6 +6111,9 @@ fi
> if test "$ivshmem" = "yes" ; then
> echo "CONFIG_IVSHMEM=y" >> $config_host_mak
> fi
> +if test "$capstone" = "yes" ; then
> + echo "CONFIG_CAPSTONE=y" >> $config_host_mak
> +fi
>
> # Hold two types of flag:
> # CONFIG_THREAD_SETNAME_BYTHREAD - we've got a way of setting the name on
Other than those minor nits:
Reviewed-by: Alex Bennée <address@hidden>
--
Alex Bennée
- Re: [Qemu-devel] [PATCH v4 4/9] disas: Support the Capstone disassembler library,
Alex Bennée <=