xref: /openbmc/qemu/linux-user/i386/cpu_loop.c (revision 5e140196)
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 "cpu_loop-common.h"
23 
24 /***********************************************************/
25 /* CPUX86 core interface */
26 
27 uint64_t cpu_get_tsc(CPUX86State *env)
28 {
29     return cpu_get_host_ticks();
30 }
31 
32 static void write_dt(void *ptr, unsigned long addr, unsigned long limit,
33               int flags)
34 {
35     unsigned int e1, e2;
36     uint32_t *p;
37     e1 = (addr << 16) | (limit & 0xffff);
38     e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);
39     e2 |= flags;
40     p = ptr;
41     p[0] = tswap32(e1);
42     p[1] = tswap32(e2);
43 }
44 
45 static uint64_t *idt_table;
46 #ifdef TARGET_X86_64
47 static void set_gate64(void *ptr, unsigned int type, unsigned int dpl,
48                        uint64_t addr, unsigned int sel)
49 {
50     uint32_t *p, e1, e2;
51     e1 = (addr & 0xffff) | (sel << 16);
52     e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
53     p = ptr;
54     p[0] = tswap32(e1);
55     p[1] = tswap32(e2);
56     p[2] = tswap32(addr >> 32);
57     p[3] = 0;
58 }
59 /* only dpl matters as we do only user space emulation */
60 static void set_idt(int n, unsigned int dpl)
61 {
62     set_gate64(idt_table + n * 2, 0, dpl, 0, 0);
63 }
64 #else
65 static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
66                      uint32_t addr, unsigned int sel)
67 {
68     uint32_t *p, e1, e2;
69     e1 = (addr & 0xffff) | (sel << 16);
70     e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
71     p = ptr;
72     p[0] = tswap32(e1);
73     p[1] = tswap32(e2);
74 }
75 
76 /* only dpl matters as we do only user space emulation */
77 static void set_idt(int n, unsigned int dpl)
78 {
79     set_gate(idt_table + n, 0, dpl, 0, 0);
80 }
81 #endif
82 
83 void cpu_loop(CPUX86State *env)
84 {
85     CPUState *cs = env_cpu(env);
86     int trapnr;
87     abi_ulong pc;
88     abi_ulong ret;
89     target_siginfo_t info;
90 
91     for(;;) {
92         cpu_exec_start(cs);
93         trapnr = cpu_exec(cs);
94         cpu_exec_end(cs);
95         process_queued_cpu_work(cs);
96 
97         switch(trapnr) {
98         case 0x80:
99             /* linux syscall from int $0x80 */
100             ret = do_syscall(env,
101                              env->regs[R_EAX],
102                              env->regs[R_EBX],
103                              env->regs[R_ECX],
104                              env->regs[R_EDX],
105                              env->regs[R_ESI],
106                              env->regs[R_EDI],
107                              env->regs[R_EBP],
108                              0, 0);
109             if (ret == -TARGET_ERESTARTSYS) {
110                 env->eip -= 2;
111             } else if (ret != -TARGET_QEMU_ESIGRETURN) {
112                 env->regs[R_EAX] = ret;
113             }
114             break;
115 #ifndef TARGET_ABI32
116         case EXCP_SYSCALL:
117             /* linux syscall from syscall instruction */
118             ret = do_syscall(env,
119                              env->regs[R_EAX],
120                              env->regs[R_EDI],
121                              env->regs[R_ESI],
122                              env->regs[R_EDX],
123                              env->regs[10],
124                              env->regs[8],
125                              env->regs[9],
126                              0, 0);
127             if (ret == -TARGET_ERESTARTSYS) {
128                 env->eip -= 2;
129             } else if (ret != -TARGET_QEMU_ESIGRETURN) {
130                 env->regs[R_EAX] = ret;
131             }
132             break;
133 #endif
134         case EXCP0B_NOSEG:
135         case EXCP0C_STACK:
136             info.si_signo = TARGET_SIGBUS;
137             info.si_errno = 0;
138             info.si_code = TARGET_SI_KERNEL;
139             info._sifields._sigfault._addr = 0;
140             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
141             break;
142         case EXCP0D_GPF:
143             /* XXX: potential problem if ABI32 */
144 #ifndef TARGET_X86_64
145             if (env->eflags & VM_MASK) {
146                 handle_vm86_fault(env);
147             } else
148 #endif
149             {
150                 info.si_signo = TARGET_SIGSEGV;
151                 info.si_errno = 0;
152                 info.si_code = TARGET_SI_KERNEL;
153                 info._sifields._sigfault._addr = 0;
154                 queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
155             }
156             break;
157         case EXCP0E_PAGE:
158             info.si_signo = TARGET_SIGSEGV;
159             info.si_errno = 0;
160             if (!(env->error_code & 1))
161                 info.si_code = TARGET_SEGV_MAPERR;
162             else
163                 info.si_code = TARGET_SEGV_ACCERR;
164             info._sifields._sigfault._addr = env->cr[2];
165             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
166             break;
167         case EXCP00_DIVZ:
168 #ifndef TARGET_X86_64
169             if (env->eflags & VM_MASK) {
170                 handle_vm86_trap(env, trapnr);
171             } else
172 #endif
173             {
174                 /* division by zero */
175                 info.si_signo = TARGET_SIGFPE;
176                 info.si_errno = 0;
177                 info.si_code = TARGET_FPE_INTDIV;
178                 info._sifields._sigfault._addr = env->eip;
179                 queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
180             }
181             break;
182         case EXCP01_DB:
183         case EXCP03_INT3:
184 #ifndef TARGET_X86_64
185             if (env->eflags & VM_MASK) {
186                 handle_vm86_trap(env, trapnr);
187             } else
188 #endif
189             {
190                 info.si_signo = TARGET_SIGTRAP;
191                 info.si_errno = 0;
192                 if (trapnr == EXCP01_DB) {
193                     info.si_code = TARGET_TRAP_BRKPT;
194                     info._sifields._sigfault._addr = env->eip;
195                 } else {
196                     info.si_code = TARGET_SI_KERNEL;
197                     info._sifields._sigfault._addr = 0;
198                 }
199                 queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
200             }
201             break;
202         case EXCP04_INTO:
203         case EXCP05_BOUND:
204 #ifndef TARGET_X86_64
205             if (env->eflags & VM_MASK) {
206                 handle_vm86_trap(env, trapnr);
207             } else
208 #endif
209             {
210                 info.si_signo = TARGET_SIGSEGV;
211                 info.si_errno = 0;
212                 info.si_code = TARGET_SI_KERNEL;
213                 info._sifields._sigfault._addr = 0;
214                 queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
215             }
216             break;
217         case EXCP06_ILLOP:
218             info.si_signo = TARGET_SIGILL;
219             info.si_errno = 0;
220             info.si_code = TARGET_ILL_ILLOPN;
221             info._sifields._sigfault._addr = env->eip;
222             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
223             break;
224         case EXCP_INTERRUPT:
225             /* just indicate that signals should be handled asap */
226             break;
227         case EXCP_DEBUG:
228             info.si_signo = TARGET_SIGTRAP;
229             info.si_errno = 0;
230             info.si_code = TARGET_TRAP_BRKPT;
231             queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
232             break;
233         case EXCP_ATOMIC:
234             cpu_exec_step_atomic(cs);
235             break;
236         default:
237             pc = env->segs[R_CS].base + env->eip;
238             EXCP_DUMP(env, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n",
239                       (long)pc, trapnr);
240             abort();
241         }
242         process_pending_signals(env);
243     }
244 }
245 
246 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
247 {
248     env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
249     env->hflags |= HF_PE_MASK | HF_CPL_MASK;
250     if (env->features[FEAT_1_EDX] & CPUID_SSE) {
251         env->cr[4] |= CR4_OSFXSR_MASK;
252         env->hflags |= HF_OSFXSR_MASK;
253     }
254 #ifndef TARGET_ABI32
255     /* enable 64 bit mode if possible */
256     if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM)) {
257         fprintf(stderr, "The selected x86 CPU does not support 64 bit mode\n");
258         exit(EXIT_FAILURE);
259     }
260     env->cr[4] |= CR4_PAE_MASK;
261     env->efer |= MSR_EFER_LMA | MSR_EFER_LME;
262     env->hflags |= HF_LMA_MASK;
263 #endif
264 
265     /* flags setup : we activate the IRQs by default as in user mode */
266     env->eflags |= IF_MASK;
267 
268     /* linux register setup */
269 #ifndef TARGET_ABI32
270     env->regs[R_EAX] = regs->rax;
271     env->regs[R_EBX] = regs->rbx;
272     env->regs[R_ECX] = regs->rcx;
273     env->regs[R_EDX] = regs->rdx;
274     env->regs[R_ESI] = regs->rsi;
275     env->regs[R_EDI] = regs->rdi;
276     env->regs[R_EBP] = regs->rbp;
277     env->regs[R_ESP] = regs->rsp;
278     env->eip = regs->rip;
279 #else
280     env->regs[R_EAX] = regs->eax;
281     env->regs[R_EBX] = regs->ebx;
282     env->regs[R_ECX] = regs->ecx;
283     env->regs[R_EDX] = regs->edx;
284     env->regs[R_ESI] = regs->esi;
285     env->regs[R_EDI] = regs->edi;
286     env->regs[R_EBP] = regs->ebp;
287     env->regs[R_ESP] = regs->esp;
288     env->eip = regs->eip;
289 #endif
290 
291     /* linux interrupt setup */
292 #ifndef TARGET_ABI32
293     env->idt.limit = 511;
294 #else
295     env->idt.limit = 255;
296 #endif
297     env->idt.base = target_mmap(0, sizeof(uint64_t) * (env->idt.limit + 1),
298                                 PROT_READ|PROT_WRITE,
299                                 MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
300     idt_table = g2h(env->idt.base);
301     set_idt(0, 0);
302     set_idt(1, 0);
303     set_idt(2, 0);
304     set_idt(3, 3);
305     set_idt(4, 3);
306     set_idt(5, 0);
307     set_idt(6, 0);
308     set_idt(7, 0);
309     set_idt(8, 0);
310     set_idt(9, 0);
311     set_idt(10, 0);
312     set_idt(11, 0);
313     set_idt(12, 0);
314     set_idt(13, 0);
315     set_idt(14, 0);
316     set_idt(15, 0);
317     set_idt(16, 0);
318     set_idt(17, 0);
319     set_idt(18, 0);
320     set_idt(19, 0);
321     set_idt(0x80, 3);
322 
323     /* linux segment setup */
324     {
325         uint64_t *gdt_table;
326         env->gdt.base = target_mmap(0, sizeof(uint64_t) * TARGET_GDT_ENTRIES,
327                                     PROT_READ|PROT_WRITE,
328                                     MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
329         env->gdt.limit = sizeof(uint64_t) * TARGET_GDT_ENTRIES - 1;
330         gdt_table = g2h(env->gdt.base);
331 #ifdef TARGET_ABI32
332         write_dt(&gdt_table[__USER_CS >> 3], 0, 0xfffff,
333                  DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK |
334                  (3 << DESC_DPL_SHIFT) | (0xa << DESC_TYPE_SHIFT));
335 #else
336         /* 64 bit code segment */
337         write_dt(&gdt_table[__USER_CS >> 3], 0, 0xfffff,
338                  DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK |
339                  DESC_L_MASK |
340                  (3 << DESC_DPL_SHIFT) | (0xa << DESC_TYPE_SHIFT));
341 #endif
342         write_dt(&gdt_table[__USER_DS >> 3], 0, 0xfffff,
343                  DESC_G_MASK | DESC_B_MASK | DESC_P_MASK | DESC_S_MASK |
344                  (3 << DESC_DPL_SHIFT) | (0x2 << DESC_TYPE_SHIFT));
345     }
346     cpu_x86_load_seg(env, R_CS, __USER_CS);
347     cpu_x86_load_seg(env, R_SS, __USER_DS);
348 #ifdef TARGET_ABI32
349     cpu_x86_load_seg(env, R_DS, __USER_DS);
350     cpu_x86_load_seg(env, R_ES, __USER_DS);
351     cpu_x86_load_seg(env, R_FS, __USER_DS);
352     cpu_x86_load_seg(env, R_GS, __USER_DS);
353     /* This hack makes Wine work... */
354     env->segs[R_FS].selector = 0;
355 #else
356     cpu_x86_load_seg(env, R_DS, 0);
357     cpu_x86_load_seg(env, R_ES, 0);
358     cpu_x86_load_seg(env, R_FS, 0);
359     cpu_x86_load_seg(env, R_GS, 0);
360 #endif
361 }
362