xref: /openbmc/qemu/linux-user/riscv/cpu_loop.c (revision 8d3031fa)
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/error-report.h"
22 #include "qemu.h"
23 #include "user-internals.h"
24 #include "cpu_loop-common.h"
25 #include "signal-common.h"
26 #include "elf.h"
27 #include "semihosting/common-semi.h"
28 
29 void cpu_loop(CPURISCVState *env)
30 {
31     CPUState *cs = env_cpu(env);
32     int trapnr;
33     target_ulong ret;
34 
35     for (;;) {
36         cpu_exec_start(cs);
37         trapnr = cpu_exec(cs);
38         cpu_exec_end(cs);
39         process_queued_cpu_work(cs);
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_riscv_flush_icache) {
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[(env->elf_flags & EF_RISCV_RVE)
57                                     ? xT0 : xA7],
58                                  env->gpr[xA0],
59                                  env->gpr[xA1],
60                                  env->gpr[xA2],
61                                  env->gpr[xA3],
62                                  env->gpr[xA4],
63                                  env->gpr[xA5],
64                                  0, 0);
65             }
66             if (ret == -QEMU_ERESTARTSYS) {
67                 env->pc -= 4;
68             } else if (ret != -QEMU_ESIGRETURN) {
69                 env->gpr[xA0] = ret;
70             }
71             if (cs->singlestep_enabled) {
72                 goto gdbstep;
73             }
74             break;
75         case RISCV_EXCP_ILLEGAL_INST:
76             force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->pc);
77             break;
78         case RISCV_EXCP_BREAKPOINT:
79         case EXCP_DEBUG:
80         gdbstep:
81             force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
82             break;
83         case RISCV_EXCP_SEMIHOST:
84             do_common_semihosting(cs);
85             env->pc += 4;
86             break;
87         default:
88             EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
89                      trapnr);
90             exit(EXIT_FAILURE);
91         }
92 
93         process_pending_signals(env);
94     }
95 }
96 
97 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
98 {
99     CPUState *cpu = env_cpu(env);
100     TaskState *ts = get_task_state(cpu);
101     struct image_info *info = ts->info;
102 
103     env->pc = regs->sepc;
104     env->gpr[xSP] = regs->sp;
105     env->elf_flags = info->elf_flags;
106 
107     if ((env->misa_ext & RVE) && !(env->elf_flags & EF_RISCV_RVE)) {
108         error_report("Incompatible ELF: RVE cpu requires RVE ABI binary");
109         exit(EXIT_FAILURE);
110     }
111 
112     ts->stack_base = info->start_stack;
113     ts->heap_base = info->brk;
114     /* This will be filled in on the first SYS_HEAPINFO call.  */
115     ts->heap_limit = 0;
116 }
117