/* * emulator main execution loop * * Copyright (c) 2003-2005 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, see . */ /* Modified for Unicorn Engine by Nguyen Anh Quynh, 2015 */ #include "tcg.h" #include "sysemu/sysemu.h" #include "uc_priv.h" static tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr); static TranslationBlock *tb_find_slow(CPUArchState *env, target_ulong pc, target_ulong cs_base, uint64_t flags); static TranslationBlock *tb_find_fast(CPUArchState *env); static void cpu_handle_debug_exception(CPUArchState *env); void cpu_loop_exit(CPUState *cpu) { cpu->current_tb = NULL; siglongjmp(cpu->jmp_env, 1); } /* exit the current TB from a signal handler. The host registers are restored in a state compatible with the CPU emulator */ void cpu_resume_from_signal(CPUState *cpu, void *puc) { /* XXX: restore cpu registers saved in host registers */ cpu->exception_index = -1; siglongjmp(cpu->jmp_env, 1); } /* main execution loop */ int cpu_exec(struct uc_struct *uc, CPUArchState *env) // qq { CPUState *cpu = ENV_GET_CPU(env); TCGContext *tcg_ctx = env->uc->tcg_ctx; CPUClass *cc = CPU_GET_CLASS(uc, cpu); #ifdef TARGET_I386 X86CPU *x86_cpu = X86_CPU(uc, cpu); #endif int ret = 0, interrupt_request; TranslationBlock *tb; uint8_t *tc_ptr; uintptr_t next_tb; struct hook *hook; if (cpu->halted) { if (!cpu_has_work(cpu)) { return EXCP_HALTED; } cpu->halted = 0; } uc->current_cpu = cpu; /* As long as current_cpu is null, up to the assignment just above, * requests by other threads to exit the execution loop are expected to * be issued using the exit_request global. We must make sure that our * evaluation of the global value is performed past the current_cpu * value transition point, which requires a memory barrier as well as * an instruction scheduling constraint on modern architectures. */ smp_mb(); if (unlikely(uc->exit_request)) { cpu->exit_request = 1; } cc->cpu_exec_enter(cpu); cpu->exception_index = -1; env->invalid_error = UC_ERR_OK; /* prepare setjmp context for exception handling */ for(;;) { if (sigsetjmp(cpu->jmp_env, 0) == 0) { if (uc->stop_request || uc->invalid_error) { break; } /* if an exception is pending, we execute it here */ if (cpu->exception_index >= 0) { //printf(">>> GOT INTERRUPT. exception idx = %x\n", cpu->exception_index); // qq if (cpu->exception_index >= EXCP_INTERRUPT) { /* exit request from the cpu execution loop */ ret = cpu->exception_index; if (ret == EXCP_DEBUG) { cpu_handle_debug_exception(env); } break; } else { bool catched = false; #if defined(CONFIG_USER_ONLY) /* if user mode only, we simulate a fake exception which will be handled outside the cpu execution loop */ #if defined(TARGET_I386) cc->do_interrupt(cpu); #endif ret = cpu->exception_index; break; #else #if defined(TARGET_X86_64) if (env->exception_is_int) { // point EIP to the next instruction after INT env->eip = env->exception_next_eip; } #endif #if defined(TARGET_MIPS) || defined(TARGET_MIPS64) env->active_tc.PC = uc->next_pc; #endif if (uc->stop_interrupt && uc->stop_interrupt(cpu->exception_index)) { // Unicorn: call registered invalid instruction callbacks HOOK_FOREACH_VAR_DECLARE; HOOK_FOREACH(uc, hook, UC_HOOK_INSN_INVALID) { if (hook->to_delete) continue; catched = ((uc_cb_hookinsn_invalid_t)hook->callback)(uc, hook->user_data); if (catched) break; } if (!catched) uc->invalid_error = UC_ERR_INSN_INVALID; } else { // Unicorn: call registered interrupt callbacks HOOK_FOREACH_VAR_DECLARE; HOOK_FOREACH(uc, hook, UC_HOOK_INTR) { if (hook->to_delete) continue; ((uc_cb_hookintr_t)hook->callback)(uc, cpu->exception_index, hook->user_data); catched = true; } if (!catched) uc->invalid_error = UC_ERR_EXCEPTION; } // Unicorn: If un-catched interrupt, stop executions. if (!catched) { cpu->halted = 1; ret = EXCP_HLT; break; } cpu->exception_index = -1; #endif } } next_tb = 0; /* force lookup of first TB */ for(;;) { interrupt_request = cpu->interrupt_request; if (unlikely(interrupt_request)) { if (unlikely(cpu->singlestep_enabled & SSTEP_NOIRQ)) { /* Mask out external interrupts for this step. */ interrupt_request &= ~CPU_INTERRUPT_SSTEP_MASK; } if (interrupt_request & CPU_INTERRUPT_DEBUG) { cpu->interrupt_request &= ~CPU_INTERRUPT_DEBUG; cpu->exception_index = EXCP_DEBUG; cpu_loop_exit(cpu); } if (interrupt_request & CPU_INTERRUPT_HALT) { cpu->interrupt_request &= ~CPU_INTERRUPT_HALT; cpu->halted = 1; cpu->exception_index = EXCP_HLT; cpu_loop_exit(cpu); } #if defined(TARGET_I386) if (interrupt_request & CPU_INTERRUPT_INIT) { cpu_svm_check_intercept_param(env, SVM_EXIT_INIT, 0); do_cpu_init(x86_cpu); cpu->exception_index = EXCP_HALTED; cpu_loop_exit(cpu); } #else if (interrupt_request & CPU_INTERRUPT_RESET) { cpu_reset(cpu); } #endif /* The target hook has 3 exit conditions: False when the interrupt isn't processed, True when it is, and we should restart on a new TB, and via longjmp via cpu_loop_exit. */ if (cc->cpu_exec_interrupt(cpu, interrupt_request)) { next_tb = 0; } /* Don't use the cached interrupt_request value, do_interrupt may have updated the EXITTB flag. */ if (cpu->interrupt_request & CPU_INTERRUPT_EXITTB) { cpu->interrupt_request &= ~CPU_INTERRUPT_EXITTB; /* ensure that no TB jump will be modified as the program flow was changed */ next_tb = 0; } } if (unlikely(cpu->exit_request)) { cpu->exit_request = 0; cpu->exception_index = EXCP_INTERRUPT; cpu_loop_exit(cpu); } tb = tb_find_fast(env); // qq if (!tb) { // invalid TB due to invalid code? uc->invalid_error = UC_ERR_FETCH_UNMAPPED; ret = EXCP_HLT; break; } /* Note: we do it here to avoid a gcc bug on Mac OS X when doing it in tb_find_slow */ if (tcg_ctx->tb_ctx.tb_invalidated_flag) { /* as some TB could have been invalidated because of memory exceptions while generating the code, we must recompute the hash index here */ next_tb = 0; tcg_ctx->tb_ctx.tb_invalidated_flag = 0; } /* see if we can patch the calling TB. When the TB spans two pages, we cannot safely do a direct jump. */ if (next_tb != 0 && tb->page_addr[1] == -1) { tb_add_jump((TranslationBlock *)(next_tb & ~TB_EXIT_MASK), next_tb & TB_EXIT_MASK, tb); } /* cpu_interrupt might be called while translating the TB, but before it is linked into a potentially infinite loop and becomes env->current_tb. Avoid starting execution if there is a pending interrupt. */ cpu->current_tb = tb; barrier(); if (likely(!cpu->exit_request)) { tc_ptr = tb->tc_ptr; /* execute the generated code */ next_tb = cpu_tb_exec(cpu, tc_ptr); // qq switch (next_tb & TB_EXIT_MASK) { case TB_EXIT_REQUESTED: /* Something asked us to stop executing * chained TBs; just continue round the main * loop. Whatever requested the exit will also * have set something else (eg exit_request or * interrupt_request) which we will handle * next time around the loop. */ tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK); next_tb = 0; break; default: break; } } cpu->current_tb = NULL; /* reset soft MMU for next block (it can currently only be set by a memory fault) */ } /* for(;;) */ } else { /* Reload env after longjmp - the compiler may have smashed all * local variables as longjmp is marked 'noreturn'. */ cpu = uc->current_cpu; env = cpu->env_ptr; cc = CPU_GET_CLASS(uc, cpu); #ifdef TARGET_I386 x86_cpu = X86_CPU(uc, cpu); #endif } } /* for(;;) */ // Unicorn: Clear any TCG exit flag that might have been left set by exit requests uc->current_cpu->tcg_exit_req = 0; cc->cpu_exec_exit(cpu); // Unicorn: flush JIT cache to because emulation might stop in // the middle of translation, thus generate incomplete code. // TODO: optimize this for better performance tb_flush(env); /* fail safe : never use current_cpu outside cpu_exec() */ // uc->current_cpu = NULL; return ret; } /* Execute a TB, and fix up the CPU state afterwards if necessary */ static tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr) { CPUArchState *env = cpu->env_ptr; TCGContext *tcg_ctx = env->uc->tcg_ctx; uintptr_t next_tb; next_tb = tcg_qemu_tb_exec(env, tb_ptr); if ((next_tb & TB_EXIT_MASK) > TB_EXIT_IDX1) { /* We didn't start executing this TB (eg because the instruction * counter hit zero); we must restore the guest PC to the address * of the start of the TB. */ CPUClass *cc = CPU_GET_CLASS(env->uc, cpu); TranslationBlock *tb = (TranslationBlock *)(next_tb & ~TB_EXIT_MASK); /* Both set_pc() & synchronize_fromtb() can be ignored when code tracing hook is installed, * or timer mode is in effect, since these already fix the PC. */ if (!HOOK_EXISTS(env->uc, UC_HOOK_CODE) && !env->uc->timeout) { // We should sync pc for R/W error. switch (env->invalid_error) { case UC_ERR_WRITE_PROT: case UC_ERR_READ_PROT: case UC_ERR_FETCH_PROT: case UC_ERR_WRITE_UNMAPPED: case UC_ERR_READ_UNMAPPED: case UC_ERR_FETCH_UNMAPPED: case UC_ERR_WRITE_UNALIGNED: case UC_ERR_READ_UNALIGNED: case UC_ERR_FETCH_UNALIGNED: break; default: if (cc->synchronize_from_tb) { // avoid sync twice when helper_uc_tracecode() already did this. if (env->uc->emu_counter <= env->uc->emu_count && !env->uc->stop_request && !env->uc->quit_request) cc->synchronize_from_tb(cpu, tb); } else { assert(cc->set_pc); // avoid sync twice when helper_uc_tracecode() already did this. if (env->uc->emu_counter <= env->uc->emu_count && !env->uc->stop_request && !env->uc->quit_request) cc->set_pc(cpu, tb->pc); } } } } if ((next_tb & TB_EXIT_MASK) == TB_EXIT_REQUESTED) { /* We were asked to stop executing TBs (probably a pending * interrupt. We've now stopped, so clear the flag. */ cpu->tcg_exit_req = 0; } return next_tb; } static TranslationBlock *tb_find_slow(CPUArchState *env, target_ulong pc, target_ulong cs_base, uint64_t flags) // qq { CPUState *cpu = ENV_GET_CPU(env); TCGContext *tcg_ctx = env->uc->tcg_ctx; TranslationBlock *tb, **ptb1; unsigned int h; tb_page_addr_t phys_pc, phys_page1; target_ulong virt_page2; tcg_ctx->tb_ctx.tb_invalidated_flag = 0; /* find translated block using physical mappings */ phys_pc = get_page_addr_code(env, pc); // qq if (phys_pc == -1) { // invalid code? return NULL; } phys_page1 = phys_pc & TARGET_PAGE_MASK; h = tb_phys_hash_func(phys_pc); ptb1 = &tcg_ctx->tb_ctx.tb_phys_hash[h]; for(;;) { tb = *ptb1; if (!tb) goto not_found; if (tb->pc == pc && tb->page_addr[0] == phys_page1 && tb->cs_base == cs_base && tb->flags == flags) { /* check next page if needed */ if (tb->page_addr[1] != -1) { tb_page_addr_t phys_page2; virt_page2 = (pc & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE; phys_page2 = get_page_addr_code(env, virt_page2); if (tb->page_addr[1] == phys_page2) goto found; } else { goto found; } } ptb1 = &tb->phys_hash_next; } not_found: /* if no translated code available, then translate it now */ tb = tb_gen_code(cpu, pc, cs_base, (int)flags, 0); // qq if (tb == NULL) { return NULL; } found: /* Move the last found TB to the head of the list */ if (likely(*ptb1)) { *ptb1 = tb->phys_hash_next; tb->phys_hash_next = tcg_ctx->tb_ctx.tb_phys_hash[h]; tcg_ctx->tb_ctx.tb_phys_hash[h] = tb; } /* we add the TB in the virtual pc hash table */ cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)] = tb; return tb; } static TranslationBlock *tb_find_fast(CPUArchState *env) // qq { CPUState *cpu = ENV_GET_CPU(env); TranslationBlock *tb; target_ulong cs_base, pc; int flags; /* we record a subset of the CPU state. It will always be the same before a given translated block is executed. */ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags); tb = cpu->tb_jmp_cache[tb_jmp_cache_hash_func(pc)]; if (unlikely(!tb || tb->pc != pc || tb->cs_base != cs_base || tb->flags != flags)) { tb = tb_find_slow(env, pc, cs_base, flags); // qq } return tb; } static void cpu_handle_debug_exception(CPUArchState *env) { CPUState *cpu = ENV_GET_CPU(env); CPUClass *cc = CPU_GET_CLASS(env->uc, cpu); CPUWatchpoint *wp; if (!cpu->watchpoint_hit) { QTAILQ_FOREACH(wp, &cpu->watchpoints, entry) { wp->flags &= ~BP_WATCHPOINT_HIT; } } cc->debug_excp_handler(cpu); }