xref: /openbmc/qemu/linux-user/riscv/cpu_loop.c (revision 0fbb5d2d)
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, signum, sigcode;
34     target_ulong sigaddr;
35     target_ulong ret;
36 
37     for (;;) {
38         cpu_exec_start(cs);
39         trapnr = cpu_exec(cs);
40         cpu_exec_end(cs);
41         process_queued_cpu_work(cs);
42 
43         signum = 0;
44         sigcode = 0;
45         sigaddr = 0;
46 
47         switch (trapnr) {
48         case EXCP_INTERRUPT:
49             /* just indicate that signals should be handled asap */
50             break;
51         case EXCP_ATOMIC:
52             cpu_exec_step_atomic(cs);
53             break;
54         case RISCV_EXCP_U_ECALL:
55             env->pc += 4;
56             if (env->gpr[xA7] == TARGET_NR_arch_specific_syscall + 15) {
57                 /* riscv_flush_icache_syscall is a no-op in QEMU as
58                    self-modifying code is automatically detected */
59                 ret = 0;
60             } else {
61                 ret = do_syscall(env,
62                                  env->gpr[(env->elf_flags & EF_RISCV_RVE)
63                                     ? xT0 : xA7],
64                                  env->gpr[xA0],
65                                  env->gpr[xA1],
66                                  env->gpr[xA2],
67                                  env->gpr[xA3],
68                                  env->gpr[xA4],
69                                  env->gpr[xA5],
70                                  0, 0);
71             }
72             if (ret == -QEMU_ERESTARTSYS) {
73                 env->pc -= 4;
74             } else if (ret != -QEMU_ESIGRETURN) {
75                 env->gpr[xA0] = ret;
76             }
77             if (cs->singlestep_enabled) {
78                 goto gdbstep;
79             }
80             break;
81         case RISCV_EXCP_ILLEGAL_INST:
82             signum = TARGET_SIGILL;
83             sigcode = TARGET_ILL_ILLOPC;
84             break;
85         case RISCV_EXCP_BREAKPOINT:
86             signum = TARGET_SIGTRAP;
87             sigcode = TARGET_TRAP_BRKPT;
88             sigaddr = env->pc;
89             break;
90         case RISCV_EXCP_SEMIHOST:
91             env->gpr[xA0] = do_common_semihosting(cs);
92             env->pc += 4;
93             break;
94         case EXCP_DEBUG:
95         gdbstep:
96             signum = TARGET_SIGTRAP;
97             sigcode = TARGET_TRAP_BRKPT;
98             break;
99         default:
100             EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
101                      trapnr);
102             exit(EXIT_FAILURE);
103         }
104 
105         if (signum) {
106             target_siginfo_t info = {
107                 .si_signo = signum,
108                 .si_errno = 0,
109                 .si_code = sigcode,
110                 ._sifields._sigfault._addr = sigaddr
111             };
112             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
113         }
114 
115         process_pending_signals(env);
116     }
117 }
118 
119 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
120 {
121     CPUState *cpu = env_cpu(env);
122     TaskState *ts = cpu->opaque;
123     struct image_info *info = ts->info;
124 
125     env->pc = regs->sepc;
126     env->gpr[xSP] = regs->sp;
127     env->elf_flags = info->elf_flags;
128 
129     if ((env->misa_ext & RVE) && !(env->elf_flags & EF_RISCV_RVE)) {
130         error_report("Incompatible ELF: RVE cpu requires RVE ABI binary");
131         exit(EXIT_FAILURE);
132     }
133 
134     ts->stack_base = info->start_stack;
135     ts->heap_base = info->brk;
136     /* This will be filled in on the first SYS_HEAPINFO call.  */
137     ts->heap_limit = 0;
138 }
139