xref: /openbmc/qemu/linux-user/riscv/cpu_loop.c (revision 46627f41)
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 "cpu_loop-common.h"
25 #include "elf.h"
26 #include "semihosting/common-semi.h"
27 
28 void cpu_loop(CPURISCVState *env)
29 {
30     CPUState *cs = env_cpu(env);
31     int trapnr, signum, sigcode;
32     target_ulong sigaddr;
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         signum = 0;
42         sigcode = 0;
43         sigaddr = 0;
44 
45         switch (trapnr) {
46         case EXCP_INTERRUPT:
47             /* just indicate that signals should be handled asap */
48             break;
49         case EXCP_ATOMIC:
50             cpu_exec_step_atomic(cs);
51             break;
52         case RISCV_EXCP_U_ECALL:
53             env->pc += 4;
54             if (env->gpr[xA7] == TARGET_NR_arch_specific_syscall + 15) {
55                 /* riscv_flush_icache_syscall is a no-op in QEMU as
56                    self-modifying code is automatically detected */
57                 ret = 0;
58             } else {
59                 ret = do_syscall(env,
60                                  env->gpr[(env->elf_flags & EF_RISCV_RVE)
61                                     ? xT0 : xA7],
62                                  env->gpr[xA0],
63                                  env->gpr[xA1],
64                                  env->gpr[xA2],
65                                  env->gpr[xA3],
66                                  env->gpr[xA4],
67                                  env->gpr[xA5],
68                                  0, 0);
69             }
70             if (ret == -TARGET_ERESTARTSYS) {
71                 env->pc -= 4;
72             } else if (ret != -TARGET_QEMU_ESIGRETURN) {
73                 env->gpr[xA0] = ret;
74             }
75             if (cs->singlestep_enabled) {
76                 goto gdbstep;
77             }
78             break;
79         case RISCV_EXCP_ILLEGAL_INST:
80             signum = TARGET_SIGILL;
81             sigcode = TARGET_ILL_ILLOPC;
82             break;
83         case RISCV_EXCP_BREAKPOINT:
84             signum = TARGET_SIGTRAP;
85             sigcode = TARGET_TRAP_BRKPT;
86             sigaddr = env->pc;
87             break;
88         case RISCV_EXCP_INST_PAGE_FAULT:
89         case RISCV_EXCP_LOAD_PAGE_FAULT:
90         case RISCV_EXCP_STORE_PAGE_FAULT:
91             signum = TARGET_SIGSEGV;
92             sigcode = TARGET_SEGV_MAPERR;
93             sigaddr = env->badaddr;
94             break;
95         case RISCV_EXCP_SEMIHOST:
96             env->gpr[xA0] = do_common_semihosting(cs);
97             env->pc += 4;
98             break;
99         case EXCP_DEBUG:
100         gdbstep:
101             signum = TARGET_SIGTRAP;
102             sigcode = TARGET_TRAP_BRKPT;
103             break;
104         default:
105             EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
106                      trapnr);
107             exit(EXIT_FAILURE);
108         }
109 
110         if (signum) {
111             target_siginfo_t info = {
112                 .si_signo = signum,
113                 .si_errno = 0,
114                 .si_code = sigcode,
115                 ._sifields._sigfault._addr = sigaddr
116             };
117             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
118         }
119 
120         process_pending_signals(env);
121     }
122 }
123 
124 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
125 {
126     CPUState *cpu = env_cpu(env);
127     TaskState *ts = cpu->opaque;
128     struct image_info *info = ts->info;
129 
130     env->pc = regs->sepc;
131     env->gpr[xSP] = regs->sp;
132     env->elf_flags = info->elf_flags;
133 
134     if ((env->misa & RVE) && !(env->elf_flags & EF_RISCV_RVE)) {
135         error_report("Incompatible ELF: RVE cpu requires RVE ABI binary");
136         exit(EXIT_FAILURE);
137     }
138 
139     ts->stack_base = info->start_stack;
140     ts->heap_base = info->brk;
141     /* This will be filled in on the first SYS_HEAPINFO call.  */
142     ts->heap_limit = 0;
143 }
144