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qemu/disas.c
Thomas Huth eb584b401f disas: Always initialize read_memory_inner_func properly 
I've recently seen this with valgrind while running the HMP tester:

==22373== Conditional jump or move depends on uninitialised value(s)
==22373==    at 0x4A41FD: arm_disas_set_info (cpu.c:504)
==22373==    by 0x3867A7: monitor_disas (disas.c:390)
==22373==    by 0x38E80E: memory_dump (monitor.c:1339)
==22373==    by 0x38FA43: handle_hmp_command (monitor.c:3123)
==22373==    by 0x38FB9E: qmp_human_monitor_command (monitor.c:613)
==22373==    by 0x4E3124: qmp_marshal_human_monitor_command (qmp-marshal.c:1736)
==22373==    by 0x769678: do_qmp_dispatch (qmp-dispatch.c:104)
==22373==    by 0x769678: qmp_dispatch (qmp-dispatch.c:131)
==22373==    by 0x38B734: handle_qmp_command (monitor.c:3853)
==22373==    by 0x76ED07: json_message_process_token (json-streamer.c:105)
==22373==    by 0x78D40A: json_lexer_feed_char (json-lexer.c:323)
==22373==    by 0x78D4CD: json_lexer_feed (json-lexer.c:373)
==22373==    by 0x38A08D: monitor_qmp_read (monitor.c:3895)

And indeed, in monitor_disas, the read_memory_inner_func variable was
not initialized, but arm_disas_set_info() expects this to be NULL
or a valid pointer. Let's properly set this to NULL in the
INIT_DISASSEMBLE_INFO to fix it in all functions that use the
disassemble_info struct.

Fixes: f7478a92dd ("Fix Thumb-1 BE32 execution")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1506524313-20037-1-git-send-email-thuth@redhat.com>
2017-10-12 12:10:38 +02:00

433 lines
11 KiB
C
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/* General "disassemble this chunk" code. Used for debugging. */
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "disas/bfd.h"
#include "elf.h"
#include "cpu.h"
#include "disas/disas.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 target address memaddr.
Transfer them to myaddr. */
int
buffer_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);
cpu_memory_rw_debug(s->cpu, memaddr, myaddr, length, 0);
return 0;
}
/* Print an error message. We can assume that this is in response to
an error return from buffer_read_memory. */
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
/* Actually, address between memaddr and memaddr + len was
out of bounds. */
(*info->fprintf_func) (info->stream,
"Address 0x%" PRIx64 " is out of bounds.\n", memaddr);
}
/* This could be in a separate file, to save minuscule amounts of space
in statically linked executables. */
/* Just print the address is hex. This is included for completeness even
though both GDB and objdump provide their own (to print symbolic
addresses). */
void
generic_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
generic_print_host_address(bfd_vma addr, struct disassemble_info *info)
{
uint64_t mask = ~0ULL >> (64 - (sizeof(void *) * 8));
generic_print_address(addr & mask, info);
}
/* Just return the given address. */
int
generic_symbol_at_address (bfd_vma addr, struct disassemble_info *info)
{
return 1;
}
bfd_vma bfd_getl64 (const bfd_byte *addr)
{
unsigned long long v;
v = (unsigned long long) addr[0];
v |= (unsigned long long) addr[1] << 8;
v |= (unsigned long long) addr[2] << 16;
v |= (unsigned long long) addr[3] << 24;
v |= (unsigned long long) addr[4] << 32;
v |= (unsigned long long) addr[5] << 40;
v |= (unsigned long long) addr[6] << 48;
v |= (unsigned long long) addr[7] << 56;
return (bfd_vma) v;
}
bfd_vma bfd_getl32 (const bfd_byte *addr)
{
unsigned long v;
v = (unsigned long) addr[0];
v |= (unsigned long) addr[1] << 8;
v |= (unsigned long) addr[2] << 16;
v |= (unsigned long) addr[3] << 24;
return (bfd_vma) v;
}
bfd_vma bfd_getb32 (const bfd_byte *addr)
{
unsigned long v;
v = (unsigned long) addr[0] << 24;
v |= (unsigned long) addr[1] << 16;
v |= (unsigned long) addr[2] << 8;
v |= (unsigned long) addr[3];
return (bfd_vma) v;
}
bfd_vma bfd_getl16 (const bfd_byte *addr)
{
unsigned long v;
v = (unsigned long) addr[0];
v |= (unsigned long) addr[1] << 8;
return (bfd_vma) v;
}
bfd_vma bfd_getb16 (const bfd_byte *addr)
{
unsigned long v;
v = (unsigned long) addr[0] << 24;
v |= (unsigned long) addr[1] << 16;
return (bfd_vma) v;
}
static int print_insn_objdump(bfd_vma pc, disassemble_info *info,
const char *prefix)
{
int i, n = info->buffer_length;
uint8_t *buf = g_malloc(n);
info->read_memory_func(pc, buf, n, info);
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]);
}
g_free(buf);
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");
}
/* Disassemble this for me please... (debugging). 'flags' has the following
values:
i386 - 1 means 16 bit code, 2 means 64 bit code
ppc - bits 0:15 specify (optionally) the machine instruction set;
bit 16 indicates little endian.
other targets - unused
*/
void target_disas(FILE *out, CPUState *cpu, target_ulong code,
target_ulong size, int flags)
{
CPUClass *cc = CPU_GET_CLASS(cpu);
target_ulong pc;
int count;
CPUDebug s;
INIT_DISASSEMBLE_INFO(s.info, out, fprintf);
s.cpu = cpu;
s.info.read_memory_func = target_read_memory;
s.info.buffer_vma = code;
s.info.buffer_length = size;
s.info.print_address_func = generic_print_address;
#ifdef TARGET_WORDS_BIGENDIAN
s.info.endian = BFD_ENDIAN_BIG;
#else
s.info.endian = BFD_ENDIAN_LITTLE;
#endif
if (cc->disas_set_info) {
cc->disas_set_info(cpu, &s.info);
}
#if defined(TARGET_I386)
if (flags == 2) {
s.info.mach = bfd_mach_x86_64;
} else if (flags == 1) {
s.info.mach = bfd_mach_i386_i8086;
} else {
s.info.mach = bfd_mach_i386_i386;
}
s.info.print_insn = print_insn_i386;
#elif defined(TARGET_PPC)
if ((flags >> 16) & 1) {
s.info.endian = BFD_ENDIAN_LITTLE;
}
if (flags & 0xFFFF) {
/* If we have a precise definition of the instruction set, use it. */
s.info.mach = flags & 0xFFFF;
} else {
#ifdef TARGET_PPC64
s.info.mach = bfd_mach_ppc64;
#else
s.info.mach = bfd_mach_ppc;
#endif
}
s.info.disassembler_options = (char *)"any";
s.info.print_insn = print_insn_ppc;
#endif
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);
#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;
if (size < count) {
fprintf(out,
"Disassembler disagrees with translator over instruction "
"decoding\n"
"Please report this to qemu-devel@nongnu.org\n");
break;
}
}
}
/* Disassemble this for me please... (debugging). */
void disas(FILE *out, void *code, unsigned long size)
{
uintptr_t pc;
int count;
CPUDebug s;
int (*print_insn)(bfd_vma pc, disassemble_info *info) = NULL;
INIT_DISASSEMBLE_INFO(s.info, out, fprintf);
s.info.print_address_func = generic_print_host_address;
s.info.buffer = code;
s.info.buffer_vma = (uintptr_t)code;
s.info.buffer_length = size;
#ifdef HOST_WORDS_BIGENDIAN
s.info.endian = BFD_ENDIAN_BIG;
#else
s.info.endian = BFD_ENDIAN_LITTLE;
#endif
#if defined(CONFIG_TCG_INTERPRETER)
print_insn = print_insn_tci;
#elif defined(__i386__)
s.info.mach = bfd_mach_i386_i386;
print_insn = print_insn_i386;
#elif defined(__x86_64__)
s.info.mach = bfd_mach_x86_64;
print_insn = print_insn_i386;
#elif defined(_ARCH_PPC)
s.info.disassembler_options = (char *)"any";
print_insn = print_insn_ppc;
#elif defined(__aarch64__) && defined(CONFIG_ARM_A64_DIS)
print_insn = print_insn_arm_a64;
#elif defined(__alpha__)
print_insn = print_insn_alpha;
#elif defined(__sparc__)
print_insn = print_insn_sparc;
s.info.mach = bfd_mach_sparc_v9b;
#elif defined(__arm__)
print_insn = print_insn_arm;
#elif defined(__MIPSEB__)
print_insn = print_insn_big_mips;
#elif defined(__MIPSEL__)
print_insn = print_insn_little_mips;
#elif defined(__m68k__)
print_insn = print_insn_m68k;
#elif defined(__s390__)
print_insn = print_insn_s390;
#elif defined(__hppa__)
print_insn = print_insn_hppa;
#endif
if (print_insn == NULL) {
print_insn = print_insn_od_host;
}
for (pc = (uintptr_t)code; size > 0; pc += count, size -= count) {
fprintf(out, "0x%08" PRIxPTR ": ", pc);
count = 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 monitor_disas_is_physical;
static int
monitor_read_memory (bfd_vma memaddr, bfd_byte *myaddr, int length,
struct disassemble_info *info)
{
CPUDebug *s = container_of(info, CPUDebug, info);
if (monitor_disas_is_physical) {
cpu_physical_memory_read(memaddr, myaddr, length);
} else {
cpu_memory_rw_debug(s->cpu, memaddr, myaddr, length, 0);
}
return 0;
}
/* Disassembler for the monitor.
See target_disas for a description of flags. */
void monitor_disas(Monitor *mon, CPUState *cpu,
target_ulong pc, int nb_insn, int is_physical, int flags)
{
CPUClass *cc = CPU_GET_CLASS(cpu);
int count, i;
CPUDebug s;
INIT_DISASSEMBLE_INFO(s.info, (FILE *)mon, monitor_fprintf);
s.cpu = 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;
#ifdef TARGET_WORDS_BIGENDIAN
s.info.endian = BFD_ENDIAN_BIG;
#else
s.info.endian = BFD_ENDIAN_LITTLE;
#endif
if (cc->disas_set_info) {
cc->disas_set_info(cpu, &s.info);
}
#if defined(TARGET_I386)
if (flags == 2) {
s.info.mach = bfd_mach_x86_64;
} else if (flags == 1) {
s.info.mach = bfd_mach_i386_i8086;
} else {
s.info.mach = bfd_mach_i386_i386;
}
s.info.print_insn = print_insn_i386;
#elif defined(TARGET_PPC)
if (flags & 0xFFFF) {
/* If we have a precise definition of the instruction set, use it. */
s.info.mach = flags & 0xFFFF;
} else {
#ifdef TARGET_PPC64
s.info.mach = bfd_mach_ppc64;
#else
s.info.mach = bfd_mach_ppc;
#endif
}
if ((flags >> 16) & 1) {
s.info.endian = BFD_ENDIAN_LITTLE;
}
s.info.print_insn = print_insn_ppc;
#endif
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++) {
monitor_printf(mon, "0x" TARGET_FMT_lx ": ", pc);
count = s.info.print_insn(pc, &s.info);
monitor_printf(mon, "\n");
if (count < 0)
break;
pc += count;
}
}
#endif
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