target-i386/excp_helper.c

   1 /*
   2  *  x86 exception helpers
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "cpu.h"
  21 #include "qemu/log.h"
  22 #include "sysemu/sysemu.h"
  23 #include "helper.h"
  24
  25 #if 0
  26 #define raise_exception_err(env, a, b)                                  \
  27     do {                                                                \
  28         qemu_log("raise_exception line=%d\n", __LINE__);                \
  29         (raise_exception_err)(env, a, b);                               \
  30     } while (0)
  31 #endif
  32
  33 void helper_raise_interrupt(CPUX86State *env, int intno, int next_eip_addend)
  34 {
  35     raise_interrupt(env, intno, 1, 0, next_eip_addend);
  36 }
  37
  38 void helper_raise_exception(CPUX86State *env, int exception_index)
  39 {
  40     raise_exception(env, exception_index);
  41 }
  42
  43 /*
  44  * Check nested exceptions and change to double or triple fault if
  45  * needed. It should only be called, if this is not an interrupt.
  46  * Returns the new exception number.
  47  */
  48 static int check_exception(CPUX86State *env, int intno, int *error_code)
  49 {
  50     int first_contributory = env->old_exception == 0 ||
  51                               (env->old_exception >= 10 &&
  52                                env->old_exception <= 13);
  53     int second_contributory = intno == 0 ||
  54                                (intno >= 10 && intno <= 13);
  55
  56     qemu_log_mask(CPU_LOG_INT, "check_exception old: 0x%x new 0x%x\n",
  57                 env->old_exception, intno);
  58
  59 #if !defined(CONFIG_USER_ONLY)
  60     if (env->old_exception == EXCP08_DBLE) {
  61         if (env->hflags & HF_SVMI_MASK) {
  62             cpu_vmexit(env, SVM_EXIT_SHUTDOWN, 0); /* does not return */
  63         }
  64
  65         qemu_log_mask(CPU_LOG_RESET, "Triple fault\n");
  66
  67         qemu_system_reset_request();
  68         return EXCP_HLT;
  69     }
  70 #endif
  71
  72     if ((first_contributory && second_contributory)
  73         || (env->old_exception == EXCP0E_PAGE &&
  74             (second_contributory || (intno == EXCP0E_PAGE)))) {
  75         intno = EXCP08_DBLE;
  76         *error_code = 0;
  77     }
  78
  79     if (second_contributory || (intno == EXCP0E_PAGE) ||
  80         (intno == EXCP08_DBLE)) {
  81         env->old_exception = intno;
  82     }
  83
  84     return intno;
  85 }
  86
  87 /*
  88  * Signal an interruption. It is executed in the main CPU loop.
  89  * is_int is TRUE if coming from the int instruction. next_eip is the
  90  * EIP value AFTER the interrupt instruction. It is only relevant if
  91  * is_int is TRUE.
  92  */
  93 static void QEMU_NORETURN raise_interrupt2(CPUX86State *env, int intno,
  94                                            int is_int, int error_code,
  95                                            int next_eip_addend)
  96 {
  97     if (!is_int) {
  98         cpu_svm_check_intercept_param(env, SVM_EXIT_EXCP_BASE + intno,
  99                                       error_code);
 100         intno = check_exception(env, intno, &error_code);
 101     } else {
 102         cpu_svm_check_intercept_param(env, SVM_EXIT_SWINT, 0);
 103     }
 104
 105     env->exception_index = intno;
 106     env->error_code = error_code;
 107     env->exception_is_int = is_int;
 108     env->exception_next_eip = env->eip + next_eip_addend;
 109     cpu_loop_exit(env);
 110 }
 111
 112 /* shortcuts to generate exceptions */
 113
 114 void QEMU_NORETURN raise_interrupt(CPUX86State *env, int intno, int is_int,
 115                                    int error_code, int next_eip_addend)
 116 {
 117     raise_interrupt2(env, intno, is_int, error_code, next_eip_addend);
 118 }
 119
 120 void raise_exception_err(CPUX86State *env, int exception_index,
 121                          int error_code)
 122 {
 123     raise_interrupt2(env, exception_index, 0, error_code, 0);
 124 }
 125
 126 void raise_exception(CPUX86State *env, int exception_index)
 127 {
 128     raise_interrupt2(env, exception_index, 0, 0, 0);
 129 }