linux-user/nios2/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.h"
  22 #include "user-internals.h"
  23 #include "cpu_loop-common.h"
  24 #include "signal-common.h"
  25
  26 void cpu_loop(CPUNios2State *env)
  27 {
  28     CPUState *cs = env_cpu(env);
  29     int trapnr, ret;
  30
  31     for (;;) {
  32         cpu_exec_start(cs);
  33         trapnr = cpu_exec(cs);
  34         cpu_exec_end(cs);
  35
  36         switch (trapnr) {
  37         case EXCP_INTERRUPT:
  38             /* just indicate that signals should be handled asap */
  39             break;
  40
  41         case EXCP_TRAP:
  42             /*
  43              * TODO: This advance should be done in the translator, as
  44              * hardware produces an advanced pc as part of all exceptions.
  45              */
  46             env->pc += 4;
  47
  48             switch (env->error_code) {
  49             case 0:
  50                 qemu_log_mask(CPU_LOG_INT, "\nSyscall\n");
  51
  52                 ret = do_syscall(env, env->regs[2],
  53                                  env->regs[4], env->regs[5], env->regs[6],
  54                                  env->regs[7], env->regs[8], env->regs[9],
  55                                  0, 0);
  56
  57                 if (ret == -QEMU_ESIGRETURN) {
  58                     /* rt_sigreturn has set all state. */
  59                     break;
  60                 }
  61                 if (ret == -QEMU_ERESTARTSYS) {
  62                     env->pc -= 4;
  63                     break;
  64                 }
  65                 /*
  66                  * See the code after translate_rc_and_ret: all negative
  67                  * values are errors (aided by userspace restricted to 2G),
  68                  * errno is returned positive in r2, and error indication
  69                  * is a boolean in r7.
  70                  */
  71                 env->regs[2] = abs(ret);
  72                 env->regs[7] = ret < 0;
  73                 break;
  74
  75             case 1:
  76                 qemu_log_mask(CPU_LOG_INT, "\nTrap 1\n");
  77                 force_sig_fault(TARGET_SIGUSR1, 0, env->pc);
  78                 break;
  79             case 2:
  80                 qemu_log_mask(CPU_LOG_INT, "\nTrap 2\n");
  81                 force_sig_fault(TARGET_SIGUSR2, 0, env->pc);
  82                 break;
  83             case 31:
  84                 qemu_log_mask(CPU_LOG_INT, "\nTrap 31\n");
  85                 /* Match kernel's breakpoint_c(). */
  86                 env->pc -= 4;
  87                 force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
  88                 break;
  89             default:
  90                 qemu_log_mask(CPU_LOG_INT, "\nTrap %d\n", env->error_code);
  91                 force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLTRP, env->pc);
  92                 break;
  93
  94             case 16: /* QEMU specific, for __kuser_cmpxchg */
  95                 {
  96                     abi_ptr g = env->regs[4];
  97                     uint32_t *h, n, o;
  98
  99                     if (g & 0x3) {
 100                         force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, g);
 101                         break;
 102                     }
 103                     ret = page_get_flags(g);
 104                     if (!(ret & PAGE_VALID)) {
 105                         force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_MAPERR, g);
 106                         break;
 107                     }
 108                     if (!(ret & PAGE_READ) || !(ret & PAGE_WRITE)) {
 109                         force_sig_fault(TARGET_SIGSEGV, TARGET_SEGV_ACCERR, g);
 110                         break;
 111                     }
 112                     h = g2h(cs, g);
 113                     o = env->regs[5];
 114                     n = env->regs[6];
 115                     env->regs[2] = qatomic_cmpxchg(h, o, n) - o;
 116                 }
 117                 break;
 118             }
 119             break;
 120
 121         case EXCP_DEBUG:
 122             force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
 123             break;
 124         default:
 125             EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
 126                      trapnr);
 127             abort();
 128         }
 129
 130         process_pending_signals(env);
 131     }
 132 }
 133
 134 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
 135 {
 136     env->regs[R_SP] = regs->sp;
 137     env->pc = regs->ea;
 138 }