linux-user/riscv/cpu_loop.c

   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 }