xref: /openbmc/qemu/bsd-user/arm/target_arch_cpu.h (revision d0bf492f)
1 /*
2  *  arm cpu init and loop
3  *
4  *  Copyright (c) 2013 Stacey D. Son
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 #ifndef TARGET_ARCH_CPU_H
21 #define TARGET_ARCH_CPU_H
22 
23 #include "target_arch.h"
24 #include "signal-common.h"
25 
26 #define TARGET_DEFAULT_CPU_MODEL "any"
27 
28 static inline void target_cpu_init(CPUARMState *env,
29         struct target_pt_regs *regs)
30 {
31     int i;
32 
33     cpsr_write(env, regs->uregs[16], CPSR_USER | CPSR_EXEC,
34                CPSRWriteByInstr);
35     for (i = 0; i < 16; i++) {
36         env->regs[i] = regs->uregs[i];
37     }
38 }
39 
40 static inline void target_cpu_loop(CPUARMState *env)
41 {
42     int trapnr, si_signo, si_code;
43     CPUState *cs = env_cpu(env);
44 
45     for (;;) {
46         cpu_exec_start(cs);
47         trapnr = cpu_exec(cs);
48         cpu_exec_end(cs);
49         process_queued_cpu_work(cs);
50         switch (trapnr) {
51         case EXCP_UDEF:
52         case EXCP_NOCP:
53         case EXCP_INVSTATE:
54             /*
55              * See arm/arm/undefined.c undefinedinstruction();
56              *
57              * A number of details aren't emulated (they likely don't matter):
58              * o Misaligned PC generates ILL_ILLADR (these can't come from qemu)
59              * o Thumb-2 instructions generate ILLADR
60              * o Both modes implement coprocessor instructions, which we don't
61              *   do here. FreeBSD just implements them for the VFP coprocessor
62              *   and special kernel breakpoints, trace points, dtrace, etc.
63              */
64             force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->regs[15]);
65             break;
66         case EXCP_SWI:
67             {
68                 int ret;
69                 abi_ulong params = get_sp_from_cpustate(env);
70                 int32_t syscall_nr = env->regs[7];
71                 int32_t arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8;
72 
73                 /* See arm/arm/syscall.c cpu_fetch_syscall_args() */
74                 if (syscall_nr == TARGET_FREEBSD_NR_syscall) {
75                     syscall_nr = env->regs[0];
76                     arg1 = env->regs[1];
77                     arg2 = env->regs[2];
78                     arg3 = env->regs[3];
79                     get_user_s32(arg4, params);
80                     params += sizeof(int32_t);
81                     get_user_s32(arg5, params);
82                     params += sizeof(int32_t);
83                     get_user_s32(arg6, params);
84                     params += sizeof(int32_t);
85                     get_user_s32(arg7, params);
86                     arg8 = 0;
87                 } else if (syscall_nr == TARGET_FREEBSD_NR___syscall) {
88                     syscall_nr = env->regs[0];
89                     arg1 = env->regs[2];
90                     arg2 = env->regs[3];
91                     get_user_s32(arg3, params);
92                     params += sizeof(int32_t);
93                     get_user_s32(arg4, params);
94                     params += sizeof(int32_t);
95                     get_user_s32(arg5, params);
96                     params += sizeof(int32_t);
97                     get_user_s32(arg6, params);
98                     arg7 = 0;
99                     arg8 = 0;
100                 } else {
101                     arg1 = env->regs[0];
102                     arg2 = env->regs[1];
103                     arg3 = env->regs[2];
104                     arg4 = env->regs[3];
105                     get_user_s32(arg5, params);
106                     params += sizeof(int32_t);
107                     get_user_s32(arg6, params);
108                     params += sizeof(int32_t);
109                     get_user_s32(arg7, params);
110                     params += sizeof(int32_t);
111                     get_user_s32(arg8, params);
112                 }
113                 ret = do_freebsd_syscall(env, syscall_nr, arg1, arg2, arg3,
114                                          arg4, arg5, arg6, arg7, arg8);
115                 /*
116                  * Compare to arm/arm/vm_machdep.c
117                  * cpu_set_syscall_retval()
118                  */
119                 if (-TARGET_EJUSTRETURN == ret) {
120                     /*
121                      * Returning from a successful sigreturn syscall.
122                      * Avoid clobbering register state.
123                      */
124                     break;
125                 }
126                 if (-TARGET_ERESTART == ret) {
127                     env->regs[15] -= env->thumb ? 2 : 4;
128                     break;
129                 }
130                 if ((unsigned int)ret >= (unsigned int)(-515)) {
131                     ret = -ret;
132                     cpsr_write(env, CPSR_C, CPSR_C, CPSRWriteByInstr);
133                     env->regs[0] = ret;
134                 } else {
135                     cpsr_write(env, 0, CPSR_C, CPSRWriteByInstr);
136                     env->regs[0] = ret; /* XXX need to handle lseek()? */
137                     /* env->regs[1] = 0; */
138                 }
139             }
140             break;
141         case EXCP_INTERRUPT:
142             /* just indicate that signals should be handled asap */
143             break;
144         case EXCP_PREFETCH_ABORT:
145         case EXCP_DATA_ABORT:
146             /*
147              * See arm/arm/trap-v6.c prefetch_abort_handler() and
148              * data_abort_handler()
149              *
150              * However, FreeBSD maps these to a generic value and then uses that
151              * to maybe fault in pages in vm/vm_fault.c:vm_fault_trap(). I
152              * believe that the indirection maps the same as Linux, but haven't
153              * chased down every single possible indirection.
154              */
155 
156             /* For user-only we don't set TTBCR_EAE, so look at the FSR. */
157             switch (env->exception.fsr & 0x1f) {
158             case 0x1: /* Alignment */
159                 si_signo = TARGET_SIGBUS;
160                 si_code = TARGET_BUS_ADRALN;
161                 break;
162             case 0x3: /* Access flag fault, level 1 */
163             case 0x6: /* Access flag fault, level 2 */
164             case 0x9: /* Domain fault, level 1 */
165             case 0xb: /* Domain fault, level 2 */
166             case 0xd: /* Permission fault, level 1 */
167             case 0xf: /* Permission fault, level 2 */
168                 si_signo = TARGET_SIGSEGV;
169                 si_code = TARGET_SEGV_ACCERR;
170                 break;
171             case 0x5: /* Translation fault, level 1 */
172             case 0x7: /* Translation fault, level 2 */
173                 si_signo = TARGET_SIGSEGV;
174                 si_code = TARGET_SEGV_MAPERR;
175                 break;
176             default:
177                 g_assert_not_reached();
178             }
179             force_sig_fault(si_signo, si_code, env->exception.vaddress);
180             break;
181         case EXCP_DEBUG:
182         case EXCP_BKPT:
183             force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->regs[15]);
184             break;
185         case EXCP_YIELD:
186             /* nothing to do here for user-mode, just resume guest code */
187             break;
188         case EXCP_ATOMIC:
189             cpu_exec_step_atomic(cs);
190             break;
191         default:
192             fprintf(stderr, "qemu: unhandled CPU exception 0x%x - aborting\n",
193                     trapnr);
194             cpu_dump_state(cs, stderr, 0);
195             abort();
196         } /* switch() */
197         process_pending_signals(env);
198     } /* for (;;) */
199 }
200 
201 static inline void target_cpu_clone_regs(CPUARMState *env, target_ulong newsp)
202 {
203     if (newsp) {
204         env->regs[13] = newsp;
205     }
206     env->regs[0] = 0;
207 }
208 
209 static inline void target_cpu_reset(CPUArchState *env)
210 {
211 }
212 
213 #endif /* TARGET_ARCH_CPU_H */
214