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/*
* 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 2.1 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 <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "sysemu/cpus.h"
#include "sysemu/tcg.h"
#include "exec/exec-all.h"
#include "qemu/plugin.h"
#include "internal.h"
bool tcg_allowed;
/* exit the current TB, but without causing any exception to be raised */
void cpu_loop_exit_noexc(CPUState *cpu)
{
cpu->exception_index = -1;
cpu_loop_exit(cpu);
}
#if defined(CONFIG_SOFTMMU)
void cpu_reloading_memory_map(void)
{
if (qemu_in_vcpu_thread() && current_cpu->running) {
/* The guest can in theory prolong the RCU critical section as long
* as it feels like. The major problem with this is that because it
* can do multiple reconfigurations of the memory map within the
* critical section, we could potentially accumulate an unbounded
* collection of memory data structures awaiting reclamation.
*
* Because the only thing we're currently protecting with RCU is the
* memory data structures, it's sufficient to break the critical section
* in this callback, which we know will get called every time the
* memory map is rearranged.
*
* (If we add anything else in the system that uses RCU to protect
* its data structures, we will need to implement some other mechanism
* to force TCG CPUs to exit the critical section, at which point this
* part of this callback might become unnecessary.)
*
* This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), which
* only protects cpu->as->dispatch. Since we know our caller is about
* to reload it, it's safe to split the critical section.
*/
rcu_read_unlock();
rcu_read_lock();
}
}
#endif
void cpu_loop_exit(CPUState *cpu)
{
/* Undo the setting in cpu_tb_exec. */
cpu->can_do_io = 1;
/* Undo any setting in generated code. */
qemu_plugin_disable_mem_helpers(cpu);
siglongjmp(cpu->jmp_env, 1);
}
void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)
{
if (pc) {
cpu_restore_state(cpu, pc);
}
cpu_loop_exit(cpu);
}
void cpu_loop_exit_atomic(CPUState *cpu, uintptr_t pc)
{
/* Prevent looping if already executing in a serial context. */
g_assert(!cpu_in_serial_context(cpu));
cpu->exception_index = EXCP_ATOMIC;
cpu_loop_exit_restore(cpu, pc);
}
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