xref: /openbmc/qemu/linux-user/riscv/cpu_loop.c (revision f85ad231)
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-common.h"
22 #include "qemu/error-report.h"
23 #include "qemu.h"
24 #include "user-internals.h"
25 #include "cpu_loop-common.h"
26 #include "signal-common.h"
27 #include "elf.h"
28 #include "semihosting/common-semi.h"
29 
30 void cpu_loop(CPURISCVState *env)
31 {
32     CPUState *cs = env_cpu(env);
33     int trapnr;
34     target_ulong ret;
35 
36     for (;;) {
37         cpu_exec_start(cs);
38         trapnr = cpu_exec(cs);
39         cpu_exec_end(cs);
40         process_queued_cpu_work(cs);
41 
42         switch (trapnr) {
43         case EXCP_INTERRUPT:
44             /* just indicate that signals should be handled asap */
45             break;
46         case EXCP_ATOMIC:
47             cpu_exec_step_atomic(cs);
48             break;
49         case RISCV_EXCP_U_ECALL:
50             env->pc += 4;
51             if (env->gpr[xA7] == TARGET_NR_arch_specific_syscall + 15) {
52                 /* riscv_flush_icache_syscall is a no-op in QEMU as
53                    self-modifying code is automatically detected */
54                 ret = 0;
55             } else {
56                 ret = do_syscall(env,
57                                  env->gpr[(env->elf_flags & EF_RISCV_RVE)
58                                     ? xT0 : xA7],
59                                  env->gpr[xA0],
60                                  env->gpr[xA1],
61                                  env->gpr[xA2],
62                                  env->gpr[xA3],
63                                  env->gpr[xA4],
64                                  env->gpr[xA5],
65                                  0, 0);
66             }
67             if (ret == -QEMU_ERESTARTSYS) {
68                 env->pc -= 4;
69             } else if (ret != -QEMU_ESIGRETURN) {
70                 env->gpr[xA0] = ret;
71             }
72             if (cs->singlestep_enabled) {
73                 goto gdbstep;
74             }
75             break;
76         case RISCV_EXCP_ILLEGAL_INST:
77             force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->pc);
78             break;
79         case RISCV_EXCP_BREAKPOINT:
80         case EXCP_DEBUG:
81         gdbstep:
82             force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
83             break;
84         case RISCV_EXCP_SEMIHOST:
85             env->gpr[xA0] = do_common_semihosting(cs);
86             env->pc += 4;
87             break;
88         default:
89             EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
90                      trapnr);
91             exit(EXIT_FAILURE);
92         }
93 
94         process_pending_signals(env);
95     }
96 }
97 
98 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
99 {
100     CPUState *cpu = env_cpu(env);
101     TaskState *ts = cpu->opaque;
102     struct image_info *info = ts->info;
103 
104     env->pc = regs->sepc;
105     env->gpr[xSP] = regs->sp;
106     env->elf_flags = info->elf_flags;
107 
108     if ((env->misa_ext & RVE) && !(env->elf_flags & EF_RISCV_RVE)) {
109         error_report("Incompatible ELF: RVE cpu requires RVE ABI binary");
110         exit(EXIT_FAILURE);
111     }
112 
113     ts->stack_base = info->start_stack;
114     ts->heap_base = info->brk;
115     /* This will be filled in on the first SYS_HEAPINFO call.  */
116     ts->heap_limit = 0;
117 }
118