postcopy: ram_enable_notify to switch on userfault
[qemu/ar7.git] / cpu-exec-common.c
blob43edf3677753d8dac7562abe2c59123624a27c19
1 /*
2 * emulator main execution loop
4 * Copyright (c) 2003-2005 Fabrice Bellard
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.
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.
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/>.
20 #include "config.h"
21 #include "cpu.h"
22 #include "sysemu/cpus.h"
23 #include "exec/memory-internal.h"
25 bool exit_request;
26 CPUState *tcg_current_cpu;
28 /* exit the current TB from a signal handler. The host registers are
29 restored in a state compatible with the CPU emulator
31 #if defined(CONFIG_SOFTMMU)
32 void cpu_resume_from_signal(CPUState *cpu, void *puc)
34 /* XXX: restore cpu registers saved in host registers */
36 cpu->exception_index = -1;
37 siglongjmp(cpu->jmp_env, 1);
40 void cpu_reloading_memory_map(void)
42 if (qemu_in_vcpu_thread()) {
43 /* The guest can in theory prolong the RCU critical section as long
44 * as it feels like. The major problem with this is that because it
45 * can do multiple reconfigurations of the memory map within the
46 * critical section, we could potentially accumulate an unbounded
47 * collection of memory data structures awaiting reclamation.
49 * Because the only thing we're currently protecting with RCU is the
50 * memory data structures, it's sufficient to break the critical section
51 * in this callback, which we know will get called every time the
52 * memory map is rearranged.
54 * (If we add anything else in the system that uses RCU to protect
55 * its data structures, we will need to implement some other mechanism
56 * to force TCG CPUs to exit the critical section, at which point this
57 * part of this callback might become unnecessary.)
59 * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), which
60 * only protects cpu->as->dispatch. Since we know our caller is about
61 * to reload it, it's safe to split the critical section.
63 rcu_read_unlock();
64 rcu_read_lock();
67 #endif
69 void cpu_loop_exit(CPUState *cpu)
71 cpu->current_tb = NULL;
72 siglongjmp(cpu->jmp_env, 1);
75 void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)
77 if (pc) {
78 cpu_restore_state(cpu, pc);
80 cpu->current_tb = NULL;
81 siglongjmp(cpu->jmp_env, 1);