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qemu/exec-i386.c

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/*
* i386 emulator main execution loop
*
* Copyright (c) 2003 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "exec-i386.h"
#include "disas.h"
//#define DEBUG_EXEC
#define DEBUG_FLUSH
//#define DEBUG_SIGNAL
/* main execution loop */
/* maximum total translate dcode allocated */
#define CODE_GEN_BUFFER_SIZE (2048 * 1024)
//#define CODE_GEN_BUFFER_SIZE (128 * 1024)
#define CODE_GEN_MAX_SIZE 65536
#define CODE_GEN_ALIGN 16 /* must be >= of the size of a icache line */
/* threshold to flush the translated code buffer */
#define CODE_GEN_BUFFER_MAX_SIZE (CODE_GEN_BUFFER_SIZE - CODE_GEN_MAX_SIZE)
#define CODE_GEN_MAX_BLOCKS (CODE_GEN_BUFFER_SIZE / 64)
#define CODE_GEN_HASH_BITS 15
#define CODE_GEN_HASH_SIZE (1 << CODE_GEN_HASH_BITS)
typedef struct TranslationBlock {
unsigned long pc; /* simulated PC corresponding to this block (EIP + CS base) */
unsigned long cs_base; /* CS base for this block */
unsigned int flags; /* flags defining in which context the code was generated */
uint8_t *tc_ptr; /* pointer to the translated code */
struct TranslationBlock *hash_next; /* next matching block */
} TranslationBlock;
TranslationBlock tbs[CODE_GEN_MAX_BLOCKS];
TranslationBlock *tb_hash[CODE_GEN_HASH_SIZE];
int nb_tbs;
uint8_t code_gen_buffer[CODE_GEN_BUFFER_SIZE];
uint8_t *code_gen_ptr;
/* thread support */
#ifdef __powerpc__
static inline int testandset (int *p)
{
int ret;
__asm__ __volatile__ (
"0: lwarx %0,0,%1 ;"
" xor. %0,%3,%0;"
" bne 1f;"
" stwcx. %2,0,%1;"
" bne- 0b;"
"1: "
: "=&r" (ret)
: "r" (p), "r" (1), "r" (0)
: "cr0", "memory");
return ret;
}
#endif
#ifdef __i386__
static inline int testandset (int *p)
{
char ret;
long int readval;
__asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
: "=q" (ret), "=m" (*p), "=a" (readval)
: "r" (1), "m" (*p), "a" (0)
: "memory");
return ret;
}
#endif
#ifdef __s390__
static inline int testandset (int *p)
{
int ret;
__asm__ __volatile__ ("0: cs %0,%1,0(%2)\n"
" jl 0b"
: "=&d" (ret)
: "r" (1), "a" (p), "0" (*p)
: "cc", "memory" );
return ret;
}
#endif
#ifdef __alpha__
int testandset (int *p)
{
int ret;
unsigned long one;
__asm__ __volatile__ ("0: mov 1,%2\n"
" ldl_l %0,%1\n"
" stl_c %2,%1\n"
" beq %2,1f\n"
".subsection 2\n"
"1: br 0b\n"
".previous"
: "=r" (ret), "=m" (*p), "=r" (one)
: "m" (*p));
return ret;
}
#endif
int global_cpu_lock = 0;
void cpu_lock(void)
{
while (testandset(&global_cpu_lock));
}
void cpu_unlock(void)
{
global_cpu_lock = 0;
}
/* exception support */
/* NOTE: not static to force relocation generation by GCC */
void raise_exception(int exception_index)
{
/* NOTE: the register at this point must be saved by hand because
longjmp restore them */
#ifdef reg_EAX
env->regs[R_EAX] = EAX;
#endif
#ifdef reg_ECX
env->regs[R_ECX] = ECX;
#endif
#ifdef reg_EDX
env->regs[R_EDX] = EDX;
#endif
#ifdef reg_EBX
env->regs[R_EBX] = EBX;
#endif
#ifdef reg_ESP
env->regs[R_ESP] = ESP;
#endif
#ifdef reg_EBP
env->regs[R_EBP] = EBP;
#endif
#ifdef reg_ESI
env->regs[R_ESI] = ESI;
#endif
#ifdef reg_EDI
env->regs[R_EDI] = EDI;
#endif
env->exception_index = exception_index;
longjmp(env->jmp_env, 1);
}
#if defined(DEBUG_EXEC)
static const char *cc_op_str[] = {
"DYNAMIC",
"EFLAGS",
"MUL",
"ADDB",
"ADDW",
"ADDL",
"ADCB",
"ADCW",
"ADCL",
"SUBB",
"SUBW",
"SUBL",
"SBBB",
"SBBW",
"SBBL",
"LOGICB",
"LOGICW",
"LOGICL",
"INCB",
"INCW",
"INCL",
"DECB",
"DECW",
"DECL",
"SHLB",
"SHLW",
"SHLL",
"SARB",
"SARW",
"SARL",
};
static void cpu_x86_dump_state(FILE *f)
{
int eflags;
eflags = cc_table[CC_OP].compute_all();
eflags |= (DF & DF_MASK);
fprintf(f,
"EAX=%08x EBX=%08X ECX=%08x EDX=%08x\n"
"ESI=%08x EDI=%08X EBP=%08x ESP=%08x\n"
"CCS=%08x CCD=%08x CCO=%-8s EFL=%c%c%c%c%c%c%c\n"
"EIP=%08x\n",
env->regs[R_EAX], env->regs[R_EBX], env->regs[R_ECX], env->regs[R_EDX],
env->regs[R_ESI], env->regs[R_EDI], env->regs[R_EBP], env->regs[R_ESP],
env->cc_src, env->cc_dst, cc_op_str[env->cc_op],
eflags & DF_MASK ? 'D' : '-',
eflags & CC_O ? 'O' : '-',
eflags & CC_S ? 'S' : '-',
eflags & CC_Z ? 'Z' : '-',
eflags & CC_A ? 'A' : '-',
eflags & CC_P ? 'P' : '-',
eflags & CC_C ? 'C' : '-',
env->eip);
#if 1
fprintf(f, "ST0=%f ST1=%f ST2=%f ST3=%f\n",
(double)ST0, (double)ST1, (double)ST(2), (double)ST(3));
#endif
}
#endif
void cpu_x86_tblocks_init(void)
{
if (!code_gen_ptr) {
code_gen_ptr = code_gen_buffer;
}
}
/* flush all the translation blocks */
static void tb_flush(void)
{
int i;
#ifdef DEBUG_FLUSH
printf("gemu: flush code_size=%d nb_tbs=%d avg_tb_size=%d\n",
code_gen_ptr - code_gen_buffer,
nb_tbs,
(code_gen_ptr - code_gen_buffer) / nb_tbs);
#endif
nb_tbs = 0;
for(i = 0;i < CODE_GEN_HASH_SIZE; i++)
tb_hash[i] = NULL;
code_gen_ptr = code_gen_buffer;
/* XXX: flush processor icache at this point */
}
/* find a translation block in the translation cache. If not found,
return NULL and the pointer to the last element of the list in pptb */
static inline TranslationBlock *tb_find(TranslationBlock ***pptb,
unsigned long pc,
unsigned long cs_base,
unsigned int flags)
{
TranslationBlock **ptb, *tb;
unsigned int h;
h = pc & (CODE_GEN_HASH_SIZE - 1);
ptb = &tb_hash[h];
for(;;) {
tb = *ptb;
if (!tb)
break;
if (tb->pc == pc && tb->cs_base == cs_base && tb->flags == flags)
return tb;
ptb = &tb->hash_next;
}
*pptb = ptb;
return NULL;
}
/* allocate a new translation block. flush the translation buffer if
too many translation blocks or too much generated code */
static inline TranslationBlock *tb_alloc(void)
{
TranslationBlock *tb;
if (nb_tbs >= CODE_GEN_MAX_BLOCKS ||
(code_gen_ptr - code_gen_buffer) >= CODE_GEN_BUFFER_MAX_SIZE)
tb_flush();
tb = &tbs[nb_tbs++];
return tb;
}
int cpu_x86_exec(CPUX86State *env1)
{
int saved_T0, saved_T1, saved_A0;
CPUX86State *saved_env;
#ifdef reg_EAX
int saved_EAX;
#endif
#ifdef reg_ECX
int saved_ECX;
#endif
#ifdef reg_EDX
int saved_EDX;
#endif
#ifdef reg_EBX
int saved_EBX;
#endif
#ifdef reg_ESP
int saved_ESP;
#endif
#ifdef reg_EBP
int saved_EBP;
#endif
#ifdef reg_ESI
int saved_ESI;
#endif
#ifdef reg_EDI
int saved_EDI;
#endif
int code_gen_size, ret;
void (*gen_func)(void);
TranslationBlock *tb, **ptb;
uint8_t *tc_ptr, *cs_base, *pc;
unsigned int flags;
/* first we save global registers */
saved_T0 = T0;
saved_T1 = T1;
saved_A0 = A0;
saved_env = env;
env = env1;
#ifdef reg_EAX
saved_EAX = EAX;
EAX = env->regs[R_EAX];
#endif
#ifdef reg_ECX
saved_ECX = ECX;
ECX = env->regs[R_ECX];
#endif
#ifdef reg_EDX
saved_EDX = EDX;
EDX = env->regs[R_EDX];
#endif
#ifdef reg_EBX
saved_EBX = EBX;
EBX = env->regs[R_EBX];
#endif
#ifdef reg_ESP
saved_ESP = ESP;
ESP = env->regs[R_ESP];
#endif
#ifdef reg_EBP
saved_EBP = EBP;
EBP = env->regs[R_EBP];
#endif
#ifdef reg_ESI
saved_ESI = ESI;
ESI = env->regs[R_ESI];
#endif
#ifdef reg_EDI
saved_EDI = EDI;
EDI = env->regs[R_EDI];
#endif
/* put eflags in CPU temporary format */
CC_SRC = env->eflags & (CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
DF = 1 - (2 * ((env->eflags >> 10) & 1));
CC_OP = CC_OP_EFLAGS;
env->eflags &= ~(DF_MASK | CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
env->interrupt_request = 0;
/* prepare setjmp context for exception handling */
if (setjmp(env->jmp_env) == 0) {
for(;;) {
if (env->interrupt_request) {
raise_exception(EXCP_INTERRUPT);
}
#ifdef DEBUG_EXEC
if (loglevel) {
cpu_x86_dump_state(logfile);
}
#endif
/* we compute the CPU state. We assume it will not
change during the whole generated block. */
flags = env->seg_cache[R_CS].seg_32bit << GEN_FLAG_CODE32_SHIFT;
flags |= env->seg_cache[R_SS].seg_32bit << GEN_FLAG_SS32_SHIFT;
flags |= (((unsigned long)env->seg_cache[R_DS].base |
(unsigned long)env->seg_cache[R_ES].base |
(unsigned long)env->seg_cache[R_SS].base) != 0) <<
GEN_FLAG_ADDSEG_SHIFT;
flags |= (env->eflags & VM_MASK) >> (17 - GEN_FLAG_VM_SHIFT);
cs_base = env->seg_cache[R_CS].base;
pc = cs_base + env->eip;
tb = tb_find(&ptb, (unsigned long)pc, (unsigned long)cs_base,
flags);
if (!tb) {
/* if no translated code available, then translate it now */
/* XXX: very inefficient: we lock all the cpus when
generating code */
cpu_lock();
tc_ptr = code_gen_ptr;
ret = cpu_x86_gen_code(code_gen_ptr, CODE_GEN_MAX_SIZE,
&code_gen_size, pc, cs_base, flags);
/* if invalid instruction, signal it */
if (ret != 0) {
cpu_unlock();
raise_exception(EXCP06_ILLOP);
}
tb = tb_alloc();
*ptb = tb;
tb->pc = (unsigned long)pc;
tb->cs_base = (unsigned long)cs_base;
tb->flags = flags;
tb->tc_ptr = tc_ptr;
tb->hash_next = NULL;
code_gen_ptr = (void *)(((unsigned long)code_gen_ptr + code_gen_size + CODE_GEN_ALIGN - 1) & ~(CODE_GEN_ALIGN - 1));
cpu_unlock();
}
if (loglevel) {
fprintf(logfile, "Trace 0x%08lx [0x%08lx] %s\n",
(long)tb->tc_ptr, (long)tb->pc,
lookup_symbol((void *)tb->pc));
fflush(logfile);
}
/* execute the generated code */
tc_ptr = tb->tc_ptr;
gen_func = (void *)tc_ptr;
gen_func();
}
}
ret = env->exception_index;
/* restore flags in standard format */
env->eflags = env->eflags | cc_table[CC_OP].compute_all() | (DF & DF_MASK);
/* restore global registers */
#ifdef reg_EAX
EAX = saved_EAX;
#endif
#ifdef reg_ECX
ECX = saved_ECX;
#endif
#ifdef reg_EDX
EDX = saved_EDX;
#endif
#ifdef reg_EBX
EBX = saved_EBX;
#endif
#ifdef reg_ESP
ESP = saved_ESP;
#endif
#ifdef reg_EBP
EBP = saved_EBP;
#endif
#ifdef reg_ESI
ESI = saved_ESI;
#endif
#ifdef reg_EDI
EDI = saved_EDI;
#endif
T0 = saved_T0;
T1 = saved_T1;
A0 = saved_A0;
env = saved_env;
return ret;
}
void cpu_x86_interrupt(CPUX86State *s)
{
s->interrupt_request = 1;
}
void cpu_x86_load_seg(CPUX86State *s, int seg_reg, int selector)
{
CPUX86State *saved_env;
saved_env = env;
env = s;
load_seg(seg_reg, selector);
env = saved_env;
}
#undef EAX
#undef ECX
#undef EDX
#undef EBX
#undef ESP
#undef EBP
#undef ESI
#undef EDI
#undef EIP
#include <signal.h>
#include <sys/ucontext.h>
static inline int handle_cpu_signal(unsigned long pc,
sigset_t *old_set)
{
#ifdef DEBUG_SIGNAL
printf("gemu: SIGSEGV pc=0x%08lx oldset=0x%08lx\n",
pc, *(unsigned long *)old_set);
#endif
if (pc >= (unsigned long)code_gen_buffer &&
pc < (unsigned long)code_gen_buffer + CODE_GEN_BUFFER_SIZE) {
/* the PC is inside the translated code. It means that we have
a virtual CPU fault */
/* we restore the process signal mask as the sigreturn should
do it */
sigprocmask(SIG_SETMASK, old_set, NULL);
/* XXX: need to compute virtual pc position by retranslating
code. The rest of the CPU state should be correct. */
raise_exception(EXCP0D_GPF);
/* never comes here */
return 1;
} else {
return 0;
}
}
int cpu_x86_signal_handler(int host_signum, struct siginfo *info,
void *puc)
{
#if defined(__i386__)
struct ucontext *uc = puc;
unsigned long pc;
sigset_t *pold_set;
#ifndef REG_EIP
/* for glibc 2.1 */
#define REG_EIP EIP
#endif
pc = uc->uc_mcontext.gregs[REG_EIP];
pold_set = &uc->uc_sigmask;
return handle_cpu_signal(pc, pold_set);
#else
#warning No CPU specific signal handler: cannot handle target SIGSEGV events
return 0;
#endif
}
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