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 "qemu/osdep.h"
  21 #include "cpu.h"
  22 #include "exec/exec-all.h"
  23 #include "qemu/log.h"
  24 #include "sysemu/sysemu.h"
  25 #include "exec/helper-proto.h"
  26
  27 void helper_raise_interrupt(CPUX86State *env, int intno, int next_eip_addend)
  28 {
  29     raise_interrupt(env, intno, 1, 0, next_eip_addend);
  30 }
  31
  32 void helper_raise_exception(CPUX86State *env, int exception_index)
  33 {
  34     raise_exception(env, exception_index);
  35 }
  36
  37 /*
  38  * Check nested exceptions and change to double or triple fault if
  39  * needed. It should only be called, if this is not an interrupt.
  40  * Returns the new exception number.
  41  */
  42 static int check_exception(CPUX86State *env, int intno, int *error_code,
  43                            uintptr_t retaddr)
  44 {
  45     int first_contributory = env->old_exception == 0 ||
  46                               (env->old_exception >= 10 &&
  47                                env->old_exception <= 13);
  48     int second_contributory = intno == 0 ||
  49                                (intno >= 10 && intno <= 13);
  50
  51     qemu_log_mask(CPU_LOG_INT, "check_exception old: 0x%x new 0x%x\n",
  52                 env->old_exception, intno);
  53
  54 #if !defined(CONFIG_USER_ONLY)
  55     if (env->old_exception == EXCP08_DBLE) {
  56         if (env->hflags & HF_SVMI_MASK) {
  57             cpu_vmexit(env, SVM_EXIT_SHUTDOWN, 0, retaddr); /* does not return */
  58         }
  59
  60         qemu_log_mask(CPU_LOG_RESET, "Triple fault\n");
  61
  62         qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
  63         return EXCP_HLT;
  64     }
  65 #endif
  66
  67     if ((first_contributory && second_contributory)
  68         || (env->old_exception == EXCP0E_PAGE &&
  69             (second_contributory || (intno == EXCP0E_PAGE)))) {
  70         intno = EXCP08_DBLE;
  71         *error_code = 0;
  72     }
  73
  74     if (second_contributory || (intno == EXCP0E_PAGE) ||
  75         (intno == EXCP08_DBLE)) {
  76         env->old_exception = intno;
  77     }
  78
  79     return intno;
  80 }
  81
  82 /*
  83  * Signal an interruption. It is executed in the main CPU loop.
  84  * is_int is TRUE if coming from the int instruction. next_eip is the
  85  * env->eip value AFTER the interrupt instruction. It is only relevant if
  86  * is_int is TRUE.
  87  */
  88 static void QEMU_NORETURN raise_interrupt2(CPUX86State *env, int intno,
  89                                            int is_int, int error_code,
  90                                            int next_eip_addend,
  91                                            uintptr_t retaddr)
  92 {
  93     CPUState *cs = CPU(x86_env_get_cpu(env));
  94
  95     if (!is_int) {
  96         cpu_svm_check_intercept_param(env, SVM_EXIT_EXCP_BASE + intno,
  97                                       error_code, retaddr);
  98         intno = check_exception(env, intno, &error_code, retaddr);
  99     } else {
 100         cpu_svm_check_intercept_param(env, SVM_EXIT_SWINT, 0, retaddr);
 101     }
 102
 103     cs->exception_index = intno;
 104     env->error_code = error_code;
 105     env->exception_is_int = is_int;
 106     env->exception_next_eip = env->eip + next_eip_addend;
 107     cpu_loop_exit_restore(cs, retaddr);
 108 }
 109
 110 /* shortcuts to generate exceptions */
 111
 112 void QEMU_NORETURN raise_interrupt(CPUX86State *env, int intno, int is_int,
 113                                    int error_code, int next_eip_addend)
 114 {
 115     raise_interrupt2(env, intno, is_int, error_code, next_eip_addend, 0);
 116 }
 117
 118 void raise_exception_err(CPUX86State *env, int exception_index,
 119                          int error_code)
 120 {
 121     raise_interrupt2(env, exception_index, 0, error_code, 0, 0);
 122 }
 123
 124 void raise_exception_err_ra(CPUX86State *env, int exception_index,
 125                             int error_code, uintptr_t retaddr)
 126 {
 127     raise_interrupt2(env, exception_index, 0, error_code, 0, retaddr);
 128 }
 129
 130 void raise_exception(CPUX86State *env, int exception_index)
 131 {
 132     raise_interrupt2(env, exception_index, 0, 0, 0, 0);
 133 }
 134
 135 void raise_exception_ra(CPUX86State *env, int exception_index, uintptr_t retaddr)
 136 {
 137     raise_interrupt2(env, exception_index, 0, 0, 0, retaddr);
 138 }