xref: /openbmc/qemu/linux-user/sparc/cpu_loop.c (revision 76f5801a)
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 "user-internals.h"
23 #include "cpu_loop-common.h"
24 #include "signal-common.h"
25 
26 #define SPARC64_STACK_BIAS 2047
27 
28 //#define DEBUG_WIN
29 
30 /* WARNING: dealing with register windows _is_ complicated. More info
31    can be found at http://www.sics.se/~psm/sparcstack.html */
32 static inline int get_reg_index(CPUSPARCState *env, int cwp, int index)
33 {
34     index = (index + cwp * 16) % (16 * env->nwindows);
35     /* wrap handling : if cwp is on the last window, then we use the
36        registers 'after' the end */
37     if (index < 8 && env->cwp == env->nwindows - 1)
38         index += 16 * env->nwindows;
39     return index;
40 }
41 
42 /* save the register window 'cwp1' */
43 static inline void save_window_offset(CPUSPARCState *env, int cwp1)
44 {
45     unsigned int i;
46     abi_ulong sp_ptr;
47 
48     sp_ptr = env->regbase[get_reg_index(env, cwp1, 6)];
49 #ifdef TARGET_SPARC64
50     if (sp_ptr & 3)
51         sp_ptr += SPARC64_STACK_BIAS;
52 #endif
53 #if defined(DEBUG_WIN)
54     printf("win_overflow: sp_ptr=0x" TARGET_ABI_FMT_lx " save_cwp=%d\n",
55            sp_ptr, cwp1);
56 #endif
57     for(i = 0; i < 16; i++) {
58         /* FIXME - what to do if put_user() fails? */
59         put_user_ual(env->regbase[get_reg_index(env, cwp1, 8 + i)], sp_ptr);
60         sp_ptr += sizeof(abi_ulong);
61     }
62 }
63 
64 static void save_window(CPUSPARCState *env)
65 {
66 #ifndef TARGET_SPARC64
67     unsigned int new_wim;
68     new_wim = ((env->wim >> 1) | (env->wim << (env->nwindows - 1))) &
69         ((1LL << env->nwindows) - 1);
70     save_window_offset(env, cpu_cwp_dec(env, env->cwp - 2));
71     env->wim = new_wim;
72 #else
73     /*
74      * cansave is zero if the spill trap handler is triggered by `save` and
75      * nonzero if triggered by a `flushw`
76      */
77     save_window_offset(env, cpu_cwp_dec(env, env->cwp - env->cansave - 2));
78     env->cansave++;
79     env->canrestore--;
80 #endif
81 }
82 
83 static void restore_window(CPUSPARCState *env)
84 {
85 #ifndef TARGET_SPARC64
86     unsigned int new_wim;
87 #endif
88     unsigned int i, cwp1;
89     abi_ulong sp_ptr;
90 
91 #ifndef TARGET_SPARC64
92     new_wim = ((env->wim << 1) | (env->wim >> (env->nwindows - 1))) &
93         ((1LL << env->nwindows) - 1);
94 #endif
95 
96     /* restore the invalid window */
97     cwp1 = cpu_cwp_inc(env, env->cwp + 1);
98     sp_ptr = env->regbase[get_reg_index(env, cwp1, 6)];
99 #ifdef TARGET_SPARC64
100     if (sp_ptr & 3)
101         sp_ptr += SPARC64_STACK_BIAS;
102 #endif
103 #if defined(DEBUG_WIN)
104     printf("win_underflow: sp_ptr=0x" TARGET_ABI_FMT_lx " load_cwp=%d\n",
105            sp_ptr, cwp1);
106 #endif
107     for(i = 0; i < 16; i++) {
108         /* FIXME - what to do if get_user() fails? */
109         get_user_ual(env->regbase[get_reg_index(env, cwp1, 8 + i)], sp_ptr);
110         sp_ptr += sizeof(abi_ulong);
111     }
112 #ifdef TARGET_SPARC64
113     env->canrestore++;
114     if (env->cleanwin < env->nwindows - 1)
115         env->cleanwin++;
116     env->cansave--;
117 #else
118     env->wim = new_wim;
119 #endif
120 }
121 
122 static void flush_windows(CPUSPARCState *env)
123 {
124     int offset, cwp1;
125 
126     offset = 1;
127     for(;;) {
128         /* if restore would invoke restore_window(), then we can stop */
129         cwp1 = cpu_cwp_inc(env, env->cwp + offset);
130 #ifndef TARGET_SPARC64
131         if (env->wim & (1 << cwp1))
132             break;
133 #else
134         if (env->canrestore == 0)
135             break;
136         env->cansave++;
137         env->canrestore--;
138 #endif
139         save_window_offset(env, cwp1);
140         offset++;
141     }
142     cwp1 = cpu_cwp_inc(env, env->cwp + 1);
143 #ifndef TARGET_SPARC64
144     /* set wim so that restore will reload the registers */
145     env->wim = 1 << cwp1;
146 #endif
147 #if defined(DEBUG_WIN)
148     printf("flush_windows: nb=%d\n", offset - 1);
149 #endif
150 }
151 
152 void cpu_loop (CPUSPARCState *env)
153 {
154     CPUState *cs = env_cpu(env);
155     int trapnr;
156     abi_long ret;
157 
158     while (1) {
159         cpu_exec_start(cs);
160         trapnr = cpu_exec(cs);
161         cpu_exec_end(cs);
162         process_queued_cpu_work(cs);
163 
164         /* Compute PSR before exposing state.  */
165         if (env->cc_op != CC_OP_FLAGS) {
166             cpu_get_psr(env);
167         }
168 
169         switch (trapnr) {
170 #ifndef TARGET_SPARC64
171         case 0x88:
172         case 0x90:
173 #else
174         case 0x110:
175         case 0x16d:
176 #endif
177             ret = do_syscall (env, env->gregs[1],
178                               env->regwptr[0], env->regwptr[1],
179                               env->regwptr[2], env->regwptr[3],
180                               env->regwptr[4], env->regwptr[5],
181                               0, 0);
182             if (ret == -QEMU_ERESTARTSYS || ret == -QEMU_ESIGRETURN) {
183                 break;
184             }
185             if ((abi_ulong)ret >= (abi_ulong)(-515)) {
186 #if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
187                 env->xcc |= PSR_CARRY;
188 #else
189                 env->psr |= PSR_CARRY;
190 #endif
191                 ret = -ret;
192             } else {
193 #if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
194                 env->xcc &= ~PSR_CARRY;
195 #else
196                 env->psr &= ~PSR_CARRY;
197 #endif
198             }
199             env->regwptr[0] = ret;
200             /* next instruction */
201             env->pc = env->npc;
202             env->npc = env->npc + 4;
203             break;
204         case 0x83: /* flush windows */
205 #ifdef TARGET_ABI32
206         case 0x103:
207 #endif
208             flush_windows(env);
209             /* next instruction */
210             env->pc = env->npc;
211             env->npc = env->npc + 4;
212             break;
213 #ifndef TARGET_SPARC64
214         case TT_WIN_OVF: /* window overflow */
215             save_window(env);
216             break;
217         case TT_WIN_UNF: /* window underflow */
218             restore_window(env);
219             break;
220 #else
221         case TT_SPILL: /* window overflow */
222             save_window(env);
223             break;
224         case TT_FILL: /* window underflow */
225             restore_window(env);
226             break;
227 #ifndef TARGET_ABI32
228         case 0x16e:
229             flush_windows(env);
230             sparc64_get_context(env);
231             break;
232         case 0x16f:
233             flush_windows(env);
234             sparc64_set_context(env);
235             break;
236 #endif
237 #endif
238         case EXCP_INTERRUPT:
239             /* just indicate that signals should be handled asap */
240             break;
241         case TT_ILL_INSN:
242             force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPC, env->pc);
243             break;
244         case EXCP_DEBUG:
245             force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
246             break;
247         case EXCP_ATOMIC:
248             cpu_exec_step_atomic(cs);
249             break;
250         default:
251             /*
252              * Most software trap numbers vector to BAD_TRAP.
253              * Handle anything not explicitly matched above.
254              */
255             if (trapnr >= TT_TRAP && trapnr <= TT_TRAP + 0x7f) {
256                 force_sig_fault(TARGET_SIGILL, ILL_ILLTRP, env->pc);
257                 break;
258             }
259             fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
260             cpu_dump_state(cs, stderr, 0);
261             exit(EXIT_FAILURE);
262         }
263         process_pending_signals (env);
264     }
265 }
266 
267 void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
268 {
269     int i;
270     env->pc = regs->pc;
271     env->npc = regs->npc;
272     env->y = regs->y;
273     for(i = 0; i < 8; i++)
274         env->gregs[i] = regs->u_regs[i];
275     for(i = 0; i < 8; i++)
276         env->regwptr[i] = regs->u_regs[i + 8];
277 }
278