cpu-exec-common.c

   1 /*
   2  *  emulator main execution loop
   3  *
   4  *  Copyright (c) 2003-2005 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "config.h"
  21 #include "cpu.h"
  22 #include "sysemu/cpus.h"
  23 #include "exec/memory-internal.h"
  24
  25 bool exit_request;
  26 CPUState *tcg_current_cpu;
  27
  28 /* exit the current TB from a signal handler. The host registers are
  29    restored in a state compatible with the CPU emulator
  30  */
  31 #if defined(CONFIG_SOFTMMU)
  32 void cpu_resume_from_signal(CPUState *cpu, void *puc)
  33 {
  34     /* XXX: restore cpu registers saved in host registers */
  35
  36     cpu->exception_index = -1;
  37     siglongjmp(cpu->jmp_env, 1);
  38 }
  39
  40 void cpu_reload_memory_map(CPUState *cpu)
  41 {
  42     AddressSpaceDispatch *d;
  43
  44     if (qemu_in_vcpu_thread()) {
  45         /* Do not let the guest prolong the critical section as much as it
  46          * as it desires.
  47          *
  48          * Currently, this is prevented by the I/O thread's periodinc kicking
  49          * of the VCPU thread (iothread_requesting_mutex, qemu_cpu_kick_thread)
  50          * but this will go away once TCG's execution moves out of the global
  51          * mutex.
  52          *
  53          * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), which
  54          * only protects cpu->as->dispatch.  Since we reload it below, we can
  55          * split the critical section.
  56          */
  57         rcu_read_unlock();
  58         rcu_read_lock();
  59     }
  60
  61     /* The CPU and TLB are protected by the iothread lock.  */
  62     d = atomic_rcu_read(&cpu->as->dispatch);
  63     cpu->memory_dispatch = d;
  64     tlb_flush(cpu, 1);
  65 }
  66 #endif
  67
  68 void cpu_loop_exit(CPUState *cpu)
  69 {
  70     cpu->current_tb = NULL;
  71     siglongjmp(cpu->jmp_env, 1);
  72 }
  73
  74 void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)
  75 {
  76     if (pc) {
  77         cpu_restore_state(cpu, pc);
  78     }
  79     cpu->current_tb = NULL;
  80     siglongjmp(cpu->jmp_env, 1);
  81 }