qemu/disas.c

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/* General "disassemble this chunk" code. Used for debugging. */
#include "qemu/osdep.h"
#include "disas/dis-asm.h"
#include "elf.h"
#include "qemu/qemu-print.h"
#include "disas/disas.h"
#include "disas/capstone.h"
typedef struct CPUDebug {
struct disassemble_info info;
CPUState *cpu;
} CPUDebug;
/* Filled in by elfload.c. Simplistic, but will do for now. */
struct syminfo *syminfos = NULL;
/*
* Get LENGTH bytes from info's buffer, at host address memaddr.
* Transfer them to myaddr.
*/
static int host_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
struct disassemble_info *info)
{
if (memaddr < info->buffer_vma
|| memaddr + length > info->buffer_vma + info->buffer_length) {
/* Out of bounds. Use EIO because GDB uses it. */
return EIO;
}
memcpy (myaddr, info->buffer + (memaddr - info->buffer_vma), length);
return 0;
}
/*
* Get LENGTH bytes from info's buffer, at target address memaddr.
* Transfer them to myaddr.
*/
static int target_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
struct disassemble_info *info)
{
CPUDebug *s = container_of(info, CPUDebug, info);
int r = cpu_memory_rw_debug(s->cpu, memaddr, myaddr, length, 0);
return r ? EIO : 0;
}
/*
* Print an error message. We can assume that this is in response to
* an error return from {host,target}_read_memory.
*/
static void perror_memory(int status, bfd_vma memaddr,
struct disassemble_info *info)
{
if (status != EIO) {
/* Can't happen. */
info->fprintf_func(info->stream, "Unknown error %d\n", status);
} else {
/* Address between memaddr and memaddr + len was out of bounds. */
info->fprintf_func(info->stream,
"Address 0x%" PRIx64 " is out of bounds.\n",
memaddr);
}
}
/* Print address in hex. */
static void print_address(bfd_vma addr, struct disassemble_info *info)
{
info->fprintf_func(info->stream, "0x%" PRIx64, addr);
}
/* Print address in hex, truncated to the width of a host virtual address. */
static void host_print_address(bfd_vma addr, struct disassemble_info *info)
{
print_address((uintptr_t)addr, info);
}
/* Stub prevents some fruitless earching in optabs disassemblers. */
static int symbol_at_address(bfd_vma addr, struct disassemble_info *info)
{
return 1;
}
static int print_insn_objdump(bfd_vma pc, disassemble_info *info,
const char *prefix)
{
int i, n = info->buffer_length;
g_autofree uint8_t *buf = g_malloc(n);
if (info->read_memory_func(pc, buf, n, info) == 0) {
for (i = 0; i < n; ++i) {
if (i % 32 == 0) {
info->fprintf_func(info->stream, "\n%s: ", prefix);
}
info->fprintf_func(info->stream, "%02x", buf[i]);
}
} else {
info->fprintf_func(info->stream, "unable to read memory");
}
return n;
}
static int print_insn_od_host(bfd_vma pc, disassemble_info *info)
{
return print_insn_objdump(pc, info, "OBJD-H");
}
static int print_insn_od_target(bfd_vma pc, disassemble_info *info)
{
return print_insn_objdump(pc, info, "OBJD-T");
}
static void initialize_debug(CPUDebug *s)
{
memset(s, 0, sizeof(*s));
s->info.arch = bfd_arch_unknown;
s->info.cap_arch = -1;
s->info.cap_insn_unit = 4;
s->info.cap_insn_split = 4;
s->info.memory_error_func = perror_memory;
s->info.symbol_at_address_func = symbol_at_address;
}
static void initialize_debug_target(CPUDebug *s, CPUState *cpu)
{
initialize_debug(s);
s->cpu = cpu;
s->info.read_memory_func = target_read_memory;
s->info.print_address_func = print_address;
#if TARGET_BIG_ENDIAN
s->info.endian = BFD_ENDIAN_BIG;
#else
s->info.endian = BFD_ENDIAN_LITTLE;
#endif
CPUClass *cc = CPU_GET_CLASS(cpu);
if (cc->disas_set_info) {
cc->disas_set_info(cpu, &s->info);
}
}
static void initialize_debug_host(CPUDebug *s)
{
initialize_debug(s);
s->info.read_memory_func = host_read_memory;
s->info.print_address_func = host_print_address;
#if HOST_BIG_ENDIAN
s->info.endian = BFD_ENDIAN_BIG;
#else
s->info.endian = BFD_ENDIAN_LITTLE;
#endif
#if defined(CONFIG_TCG_INTERPRETER)
s->info.print_insn = print_insn_tci;
#elif defined(__i386__)
s->info.mach = bfd_mach_i386_i386;
s->info.cap_arch = CS_ARCH_X86;
s->info.cap_mode = CS_MODE_32;
s->info.cap_insn_unit = 1;
s->info.cap_insn_split = 8;
#elif defined(__x86_64__)
s->info.mach = bfd_mach_x86_64;
s->info.cap_arch = CS_ARCH_X86;
s->info.cap_mode = CS_MODE_64;
s->info.cap_insn_unit = 1;
s->info.cap_insn_split = 8;
#elif defined(_ARCH_PPC)
s->info.cap_arch = CS_ARCH_PPC;
# ifdef _ARCH_PPC64
s->info.cap_mode = CS_MODE_64;
# endif
#elif defined(__riscv) && defined(CONFIG_RISCV_DIS)
#if defined(_ILP32) || (__riscv_xlen == 32)
s->info.print_insn = print_insn_riscv32;
#elif defined(_LP64)
s->info.print_insn = print_insn_riscv64;
#else
#error unsupported RISC-V ABI
#endif
#elif defined(__aarch64__)
s->info.cap_arch = CS_ARCH_ARM64;
#elif defined(__alpha__)
s->info.print_insn = print_insn_alpha;
#elif defined(__sparc__)
s->info.print_insn = print_insn_sparc;
s->info.mach = bfd_mach_sparc_v9b;
#elif defined(__arm__)
/* TCG only generates code for arm mode. */
s->info.cap_arch = CS_ARCH_ARM;
#elif defined(__MIPSEB__)
s->info.print_insn = print_insn_big_mips;
#elif defined(__MIPSEL__)
s->info.print_insn = print_insn_little_mips;
#elif defined(__m68k__)
s->info.print_insn = print_insn_m68k;
#elif defined(__s390__)
s->info.cap_arch = CS_ARCH_SYSZ;
s->info.cap_insn_unit = 2;
s->info.cap_insn_split = 6;
#elif defined(__hppa__)
s->info.print_insn = print_insn_hppa;
#elif defined(__loongarch__)
s->info.print_insn = print_insn_loongarch;
#endif
}
/* Disassemble this for me please... (debugging). */
void target_disas(FILE *out, CPUState *cpu, target_ulong code,
target_ulong size)
{
target_ulong pc;
int count;
CPUDebug s;
initialize_debug_target(&s, cpu);
s.info.fprintf_func = fprintf;
s.info.stream = out;
s.info.buffer_vma = code;
s.info.buffer_length = size;
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;
}
for (pc = code; size > 0; pc += count, size -= count) {
fprintf(out, "0x" TARGET_FMT_lx ": ", pc);
count = s.info.print_insn(pc, &s.info);
fprintf(out, "\n");
if (count < 0)
break;
if (size < count) {
fprintf(out,
"Disassembler disagrees with translator over instruction "
"decoding\n"
"Please report this to qemu-devel@nongnu.org\n");
break;
}
}
}
static int G_GNUC_PRINTF(2, 3)
gstring_printf(FILE *stream, const char *fmt, ...)
{
/* We abuse the FILE parameter to pass a GString. */
GString *s = (GString *)stream;
int initial_len = s->len;
va_list va;
va_start(va, fmt);
g_string_append_vprintf(s, fmt, va);
va_end(va);
return s->len - initial_len;
}
static void plugin_print_address(bfd_vma addr, struct disassemble_info *info)
{
/* does nothing */
}
/*
* We should only be dissembling one instruction at a time here. If
* there is left over it usually indicates the front end has read more
* bytes than it needed.
*/
char *plugin_disas(CPUState *cpu, uint64_t addr, size_t size)
{
CPUDebug s;
GString *ds = g_string_new(NULL);
initialize_debug_target(&s, cpu);
s.info.fprintf_func = gstring_printf;
s.info.stream = (FILE *)ds; /* abuse this slot */
s.info.buffer_vma = addr;
s.info.buffer_length = size;
s.info.print_address_func = plugin_print_address;
if (s.info.cap_arch >= 0 && cap_disas_plugin(&s.info, addr, size)) {
; /* done */
} else if (s.info.print_insn) {
s.info.print_insn(addr, &s.info);
} else {
; /* cannot disassemble -- return empty string */
}
/* Return the buffer, freeing the GString container. */
return g_string_free(ds, false);
}
/* Disassemble this for me please... (debugging). */
void disas(FILE *out, const void *code, unsigned long size)
{
uintptr_t pc;
int count;
CPUDebug s;
initialize_debug_host(&s);
s.info.fprintf_func = fprintf;
s.info.stream = out;
s.info.buffer = code;
s.info.buffer_vma = (uintptr_t)code;
s.info.buffer_length = size;
if (s.info.cap_arch >= 0 && cap_disas_host(&s.info, code, size)) {
return;
}
if (s.info.print_insn == NULL) {
s.info.print_insn = print_insn_od_host;
}
for (pc = (uintptr_t)code; size > 0; pc += count, size -= count) {
fprintf(out, "0x%08" PRIxPTR ": ", pc);
count = s.info.print_insn(pc, &s.info);
fprintf(out, "\n");
if (count < 0) {
break;
}
}
}
/* Look up symbol for debugging purpose. Returns "" if unknown. */
const char *lookup_symbol(target_ulong orig_addr)
{
const char *symbol = "";
struct syminfo *s;
for (s = syminfos; s; s = s->next) {
symbol = s->lookup_symbol(s, orig_addr);
if (symbol[0] != '\0') {
break;
}
}
return symbol;
}
#if !defined(CONFIG_USER_ONLY)
#include "monitor/monitor.h"
static int
physical_read_memory(bfd_vma memaddr, bfd_byte *myaddr, int length,
struct disassemble_info *info)
{
CPUDebug *s = container_of(info, CPUDebug, info);
MemTxResult res;
res = address_space_read(s->cpu->as, memaddr, MEMTXATTRS_UNSPECIFIED,
myaddr, length);
return res == MEMTX_OK ? 0 : EIO;
}
/* Disassembler for the monitor. */
void monitor_disas(Monitor *mon, CPUState *cpu,
target_ulong pc, int nb_insn, int is_physical)
{
int count, i;
CPUDebug s;
g_autoptr(GString) ds = g_string_new("");
initialize_debug_target(&s, cpu);
s.info.fprintf_func = gstring_printf;
s.info.stream = (FILE *)ds; /* abuse this slot */
if (is_physical) {
s.info.read_memory_func = physical_read_memory;
}
s.info.buffer_vma = pc;
if (s.info.cap_arch >= 0 && cap_disas_monitor(&s.info, pc, nb_insn)) {
monitor_puts(mon, ds->str);
return;
}
if (!s.info.print_insn) {
monitor_printf(mon, "0x" TARGET_FMT_lx
": Asm output not supported on this arch\n", pc);
return;
}
for (i = 0; i < nb_insn; i++) {
g_string_append_printf(ds, "0x" TARGET_FMT_lx ": ", pc);
count = s.info.print_insn(pc, &s.info);
g_string_append_c(ds, '\n');
if (count < 0) {
break;
}
pc += count;
}
monitor_puts(mon, ds->str);
}
#endif