xref: /openbmc/qemu/linux-user/riscv/cpu_loop.c (revision 40d6ee94)
1 /*
2  *  qemu user cpu loop
3  *
4  *  Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  *  This program is free software; you can redistribute it and/or modify
7  *  it under the terms of the GNU General Public License as published by
8  *  the Free Software Foundation; either version 2 of the License, or
9  *  (at your option) any later version.
10  *
11  *  This program 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
14  *  GNU General Public License for more details.
15  *
16  *  You should have received a copy of the GNU General Public License
17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "qemu.h"
22 #include "cpu_loop-common.h"
23 
24 void cpu_loop(CPURISCVState *env)
25 {
26     CPUState *cs = CPU(riscv_env_get_cpu(env));
27     int trapnr, signum, sigcode;
28     target_ulong sigaddr;
29     target_ulong ret;
30 
31     for (;;) {
32         cpu_exec_start(cs);
33         trapnr = cpu_exec(cs);
34         cpu_exec_end(cs);
35         process_queued_cpu_work(cs);
36 
37         signum = 0;
38         sigcode = 0;
39         sigaddr = 0;
40 
41         switch (trapnr) {
42         case EXCP_INTERRUPT:
43             /* just indicate that signals should be handled asap */
44             break;
45         case EXCP_ATOMIC:
46             cpu_exec_step_atomic(cs);
47             break;
48         case RISCV_EXCP_U_ECALL:
49             env->pc += 4;
50             if (env->gpr[xA7] == TARGET_NR_arch_specific_syscall + 15) {
51                 /* riscv_flush_icache_syscall is a no-op in QEMU as
52                    self-modifying code is automatically detected */
53                 ret = 0;
54             } else {
55                 ret = do_syscall(env,
56                                  env->gpr[xA7],
57                                  env->gpr[xA0],
58                                  env->gpr[xA1],
59                                  env->gpr[xA2],
60                                  env->gpr[xA3],
61                                  env->gpr[xA4],
62                                  env->gpr[xA5],
63                                  0, 0);
64             }
65             if (ret == -TARGET_ERESTARTSYS) {
66                 env->pc -= 4;
67             } else if (ret != -TARGET_QEMU_ESIGRETURN) {
68                 env->gpr[xA0] = ret;
69             }
70             if (cs->singlestep_enabled) {
71                 goto gdbstep;
72             }
73             break;
74         case RISCV_EXCP_ILLEGAL_INST:
75             signum = TARGET_SIGILL;
76             sigcode = TARGET_ILL_ILLOPC;
77             break;
78         case RISCV_EXCP_BREAKPOINT:
79             signum = TARGET_SIGTRAP;
80             sigcode = TARGET_TRAP_BRKPT;
81             sigaddr = env->pc;
82             break;
83         case RISCV_EXCP_INST_PAGE_FAULT:
84         case RISCV_EXCP_LOAD_PAGE_FAULT:
85         case RISCV_EXCP_STORE_PAGE_FAULT:
86             signum = TARGET_SIGSEGV;
87             sigcode = TARGET_SEGV_MAPERR;
88             break;
89         case EXCP_DEBUG:
90         gdbstep:
91             signum = TARGET_SIGTRAP;
92             sigcode = TARGET_TRAP_BRKPT;
93             break;
94         default:
95             EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
96                      trapnr);
97             exit(EXIT_FAILURE);
98         }
99 
100         if (signum) {
101             target_siginfo_t info = {
102                 .si_signo = signum,
103                 .si_errno = 0,
104                 .si_code = sigcode,
105                 ._sifields._sigfault._addr = sigaddr
106             };
107             queue_signal(env, info.si_signo, QEMU_SI_KILL, &info);
108         }
109 
110         process_pending_signals(env);
111     }
112 }
113 
114 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
115 {
116     env->pc = regs->sepc;
117     env->gpr[xSP] = regs->sp;
118 }
119