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_SIGNAL
/* main execution loop */
/* thread support */
spinlock_t global_cpu_lock = SPIN_LOCK_UNLOCKED;
void cpu_lock(void)
{
spin_lock(&global_cpu_lock);
}
void cpu_unlock(void)
{
spin_unlock(&global_cpu_lock);
}
void cpu_loop_exit(void)
{
/* NOTE: the register at this point must be saved by hand because
longjmp restore them */
#ifdef __sparc__
/* We have to stay in the same register window as our caller,
* thus this trick.
*/
__asm__ __volatile__("restore\n\t"
"mov\t%o0, %i0");
#endif
#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
longjmp(env->jmp_env, 1);
}
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) {
T0 = 0; /* force lookup of first TB */
for(;;) {
if (env->interrupt_request) {
env->exception_index = EXCP_INTERRUPT;
cpu_loop_exit();
}
#ifdef DEBUG_EXEC
if (loglevel) {
/* XXX: save all volatile state in cpu state */
/* restore flags in standard format */
env->regs[R_EAX] = EAX;
env->regs[R_EBX] = EBX;
env->regs[R_ECX] = ECX;
env->regs[R_EDX] = EDX;
env->regs[R_ESI] = ESI;
env->regs[R_EDI] = EDI;
env->regs[R_EBP] = EBP;
env->regs[R_ESP] = ESP;
env->eflags = env->eflags | cc_table[CC_OP].compute_all() | (DF & DF_MASK);
cpu_x86_dump_state(env, logfile, 0);
env->eflags &= ~(DF_MASK | CC_O | CC_S | CC_Z | CC_A | CC_P | CC_C);
}
#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;
if (!(env->eflags & VM_MASK)) {
flags |= (env->segs[R_CS] & 3) << GEN_FLAG_CPL_SHIFT;
} else {
/* NOTE: a dummy CPL is kept */
flags |= (1 << GEN_FLAG_VM_SHIFT);
flags |= (3 << GEN_FLAG_CPL_SHIFT);
}
flags |= (env->eflags & (IOPL_MASK | TF_MASK));
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) {
spin_lock(&tb_lock);
/* if no translated code available, then translate it now */
tb = tb_alloc((unsigned long)pc);
if (!tb) {
/* flush must be done */
tb_flush();
/* cannot fail at this point */
tb = tb_alloc((unsigned long)pc);
/* don't forget to invalidate previous TB info */
ptb = &tb_hash[tb_hash_func((unsigned long)pc)];
T0 = 0;
}
tc_ptr = code_gen_ptr;
tb->tc_ptr = tc_ptr;
tb->cs_base = (unsigned long)cs_base;
tb->flags = flags;
ret = cpu_x86_gen_code(tb, CODE_GEN_MAX_SIZE, &code_gen_size);
/* if invalid instruction, signal it */
if (ret != 0) {
/* NOTE: the tb is allocated but not linked, so we
can leave it */
spin_unlock(&tb_lock);
raise_exception(EXCP06_ILLOP);
}
*ptb = tb;
tb->hash_next = NULL;
tb_link(tb);
code_gen_ptr = (void *)(((unsigned long)code_gen_ptr + code_gen_size + CODE_GEN_ALIGN - 1) & ~(CODE_GEN_ALIGN - 1));
spin_unlock(&tb_lock);
}
#ifdef DEBUG_EXEC
if (loglevel) {
fprintf(logfile, "Trace 0x%08lx [0x%08lx] %s\n",
(long)tb->tc_ptr, (long)tb->pc,
lookup_symbol((void *)tb->pc));
}
#endif
/* see if we can patch the calling TB */
if (T0 != 0 && !(env->eflags & TF_MASK)) {
spin_lock(&tb_lock);
tb_add_jump((TranslationBlock *)(T0 & ~3), T0 & 3, tb);
spin_unlock(&tb_lock);
}
tc_ptr = tb->tc_ptr;
/* execute the generated code */
gen_func = (void *)tc_ptr;
#ifdef __sparc__
__asm__ __volatile__("call %0\n\t"
" mov %%o7,%%i0"
: /* no outputs */
: "r" (gen_func)
: "i0", "i1", "i2", "i3", "i4", "i5");
#else
gen_func();
#endif
}
}
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;
if (env->eflags & VM_MASK) {
SegmentCache *sc;
selector &= 0xffff;
sc = &env->seg_cache[seg_reg];
/* NOTE: in VM86 mode, limit and seg_32bit are never reloaded,
so we must load them here */
sc->base = (void *)(selector << 4);
sc->limit = 0xffff;
sc->seg_32bit = 0;
env->segs[seg_reg] = selector;
} else {
load_seg(seg_reg, selector, 0);
}
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>
/* 'pc' is the host PC at which the exception was raised. 'address' is
the effective address of the memory exception. 'is_write' is 1 if a
write caused the exception and otherwise 0'. 'old_set' is the
signal set which should be restored */
static inline int handle_cpu_signal(unsigned long pc, unsigned long address,
int is_write, sigset_t *old_set)
{
TranslationBlock *tb;
int ret;
uint32_t found_pc;
#if defined(DEBUG_SIGNAL)
printf("qemu: SIGSEGV pc=0x%08lx address=%08lx wr=%d oldset=0x%08lx\n",
pc, address, is_write, *(unsigned long *)old_set);
#endif
/* XXX: locking issue */
if (is_write && page_unprotect(address)) {
return 1;
}
tb = tb_find_pc(pc);
if (tb) {
/* the PC is inside the translated code. It means that we have
a virtual CPU fault */
ret = cpu_x86_search_pc(tb, &found_pc, pc);
if (ret < 0)
return 0;
env->eip = found_pc - tb->cs_base;
env->cr2 = address;
/* we restore the process signal mask as the sigreturn should
do it (XXX: use sigsetjmp) */
sigprocmask(SIG_SETMASK, old_set, NULL);
raise_exception_err(EXCP0E_PAGE, 4 | (is_write << 1));
/* never comes here */
return 1;
} else {
return 0;
}
}
#if defined(__i386__)
int cpu_x86_signal_handler(int host_signum, struct siginfo *info,
void *puc)
{
struct ucontext *uc = puc;
unsigned long pc;
#ifndef REG_EIP
/* for glibc 2.1 */
#define REG_EIP EIP
#define REG_ERR ERR
#define REG_TRAPNO TRAPNO
#endif
pc = uc->uc_mcontext.gregs[REG_EIP];
return handle_cpu_signal(pc, (unsigned long)info->si_addr,
uc->uc_mcontext.gregs[REG_TRAPNO] == 0xe ?
(uc->uc_mcontext.gregs[REG_ERR] >> 1) & 1 : 0,
&uc->uc_sigmask);
}
#elif defined(__powerpc)
int cpu_x86_signal_handler(int host_signum, struct siginfo *info,
void *puc)
{
struct ucontext *uc = puc;
struct pt_regs *regs = uc->uc_mcontext.regs;
unsigned long pc;
int is_write;
pc = regs->nip;
is_write = 0;
#if 0
/* ppc 4xx case */
if (regs->dsisr & 0x00800000)
is_write = 1;
#else
if (regs->trap != 0x400 && (regs->dsisr & 0x02000000))
is_write = 1;
#endif
return handle_cpu_signal(pc, (unsigned long)info->si_addr,
is_write, &uc->uc_sigmask);
}
#else
#error CPU specific signal handler needed
#endif