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(a, b)\
27do {\
28    qemu_log("raise_exception line=%d\n", __LINE__);\
29    (raise_exception_err)(a, b);\
30} while (0)
31#endif
32
33void helper_raise_interrupt(CPUX86State *env, int intno, int next_eip_addend)
34{
35    raise_interrupt(env, intno, 1, 0, next_eip_addend);
36}
37
38void 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 */
48static 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            helper_vmexit(env, SVM_EXIT_SHUTDOWN, 0); /* does not return */
63
64        qemu_log_mask(CPU_LOG_RESET, "Triple fault\n");
65
66        qemu_system_reset_request();
67        return EXCP_HLT;
68    }
69#endif
70
71    if ((first_contributory && second_contributory)
72        || (env->old_exception == EXCP0E_PAGE &&
73            (second_contributory || (intno == EXCP0E_PAGE)))) {
74        intno = EXCP08_DBLE;
75        *error_code = 0;
76    }
77
78    if (second_contributory || (intno == EXCP0E_PAGE) ||
79        (intno == EXCP08_DBLE))
80        env->old_exception = intno;
81
82    return intno;
83}
84
85/*
86 * Signal an interruption. It is executed in the main CPU loop.
87 * is_int is TRUE if coming from the int instruction. next_eip is the
88 * EIP value AFTER the interrupt instruction. It is only relevant if
89 * is_int is TRUE.
90 */
91void QEMU_NORETURN raise_interrupt(CPUX86State *env,
92                                   int intno, int is_int, int error_code,
93                                   int next_eip_addend)
94{
95    if (!is_int) {
96        helper_svm_check_intercept_param(env, SVM_EXIT_EXCP_BASE + intno, error_code);
97        intno = check_exception(env, intno, &error_code);
98    } else {
99        helper_svm_check_intercept_param(env, SVM_EXIT_SWINT, 0);
100    }
101
102    env->exception_index = intno;
103    env->error_code = error_code;
104    env->exception_is_int = is_int;
105    env->exception_next_eip = env->eip + next_eip_addend;
106    cpu_loop_exit(env);
107}
108
109/* shortcuts to generate exceptions */
110
111void raise_exception_err(CPUX86State *env,
112                         int exception_index, int error_code)
113{
114    raise_interrupt(env, exception_index, 0, error_code, 0);
115}
116
117void raise_exception(CPUX86State *env, int exception_index)
118{
119    raise_interrupt(env, exception_index, 0, 0, 0);
120}
121