1/*
2 * Altera Nios II helper routines.
3 *
4 * Copyright (c) 2012 Chris Wulff <crwulff@gmail.com>
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 2.1 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
18 * <http://www.gnu.org/licenses/lgpl-2.1.html>
19 */
20
21#include "qemu/osdep.h"
22
23#include "cpu.h"
24#include "qemu/host-utils.h"
25#include "exec/exec-all.h"
26#include "exec/cpu_ldst.h"
27#include "exec/log.h"
28#include "exec/helper-proto.h"
29#include "hw/semihosting/semihost.h"
30
31#if defined(CONFIG_USER_ONLY)
32
33void nios2_cpu_do_interrupt(CPUState *cs)
34{
35 Nios2CPU *cpu = NIOS2_CPU(cs);
36 CPUNios2State *env = &cpu->env;
37 cs->exception_index = -1;
38 env->regs[R_EA] = env->regs[R_PC] + 4;
39}
40
41bool nios2_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
42 MMUAccessType access_type, int mmu_idx,
43 bool probe, uintptr_t retaddr)
44{
45 cs->exception_index = 0xaa;
46 cpu_loop_exit_restore(cs, retaddr);
47}
48
49#else /* !CONFIG_USER_ONLY */
50
51void nios2_cpu_do_interrupt(CPUState *cs)
52{
53 Nios2CPU *cpu = NIOS2_CPU(cs);
54 CPUNios2State *env = &cpu->env;
55
56 switch (cs->exception_index) {
57 case EXCP_IRQ:
58 assert(env->regs[CR_STATUS] & CR_STATUS_PIE);
59
60 qemu_log_mask(CPU_LOG_INT, "interrupt at pc=%x\n", env->regs[R_PC]);
61
62 env->regs[CR_ESTATUS] = env->regs[CR_STATUS];
63 env->regs[CR_STATUS] |= CR_STATUS_IH;
64 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
65
66 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
67 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
68
69 env->regs[R_EA] = env->regs[R_PC] + 4;
70 env->regs[R_PC] = cpu->exception_addr;
71 break;
72
73 case EXCP_TLBD:
74 if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
75 qemu_log_mask(CPU_LOG_INT, "TLB MISS (fast) at pc=%x\n",
76 env->regs[R_PC]);
77
78 /* Fast TLB miss */
79 /* Variation from the spec. Table 3-35 of the cpu reference shows
80 * estatus not being changed for TLB miss but this appears to
81 * be incorrect. */
82 env->regs[CR_ESTATUS] = env->regs[CR_STATUS];
83 env->regs[CR_STATUS] |= CR_STATUS_EH;
84 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
85
86 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
87 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
88
89 env->regs[CR_TLBMISC] &= ~CR_TLBMISC_DBL;
90 env->regs[CR_TLBMISC] |= CR_TLBMISC_WR;
91
92 env->regs[R_EA] = env->regs[R_PC] + 4;
93 env->regs[R_PC] = cpu->fast_tlb_miss_addr;
94 } else {
95 qemu_log_mask(CPU_LOG_INT, "TLB MISS (double) at pc=%x\n",
96 env->regs[R_PC]);
97
98 /* Double TLB miss */
99 env->regs[CR_STATUS] |= CR_STATUS_EH;
100 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
101
102 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
103 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
104
105 env->regs[CR_TLBMISC] |= CR_TLBMISC_DBL;
106
107 env->regs[R_PC] = cpu->exception_addr;
108 }
109 break;
110
111 case EXCP_TLBR:
112 case EXCP_TLBW:
113 case EXCP_TLBX:
114 qemu_log_mask(CPU_LOG_INT, "TLB PERM at pc=%x\n", env->regs[R_PC]);
115
116 env->regs[CR_ESTATUS] = env->regs[CR_STATUS];
117 env->regs[CR_STATUS] |= CR_STATUS_EH;
118 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
119
120 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
121 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
122
123 if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
124 env->regs[CR_TLBMISC] |= CR_TLBMISC_WR;
125 }
126
127 env->regs[R_EA] = env->regs[R_PC] + 4;
128 env->regs[R_PC] = cpu->exception_addr;
129 break;
130
131 case EXCP_SUPERA:
132 case EXCP_SUPERI:
133 case EXCP_SUPERD:
134 qemu_log_mask(CPU_LOG_INT, "SUPERVISOR exception at pc=%x\n",
135 env->regs[R_PC]);
136
137 if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
138 env->regs[CR_ESTATUS] = env->regs[CR_STATUS];
139 env->regs[R_EA] = env->regs[R_PC] + 4;
140 }
141
142 env->regs[CR_STATUS] |= CR_STATUS_EH;
143 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
144
145 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
146 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
147
148 env->regs[R_PC] = cpu->exception_addr;
149 break;
150
151 case EXCP_ILLEGAL:
152 case EXCP_TRAP:
153 qemu_log_mask(CPU_LOG_INT, "TRAP exception at pc=%x\n",
154 env->regs[R_PC]);
155
156 if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
157 env->regs[CR_ESTATUS] = env->regs[CR_STATUS];
158 env->regs[R_EA] = env->regs[R_PC] + 4;
159 }
160
161 env->regs[CR_STATUS] |= CR_STATUS_EH;
162 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
163
164 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
165 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
166
167 env->regs[R_PC] = cpu->exception_addr;
168 break;
169
170 case EXCP_BREAK:
171 qemu_log_mask(CPU_LOG_INT, "BREAK exception at pc=%x\n",
172 env->regs[R_PC]);
173 /* The semihosting instruction is "break 1". */
174 if (semihosting_enabled() &&
175 cpu_ldl_code(env, env->regs[R_PC]) == 0x003da07a) {
176 qemu_log_mask(CPU_LOG_INT, "Entering semihosting\n");
177 env->regs[R_PC] += 4;
178 do_nios2_semihosting(env);
179 break;
180 }
181
182 if ((env->regs[CR_STATUS] & CR_STATUS_EH) == 0) {
183 env->regs[CR_BSTATUS] = env->regs[CR_STATUS];
184 env->regs[R_BA] = env->regs[R_PC] + 4;
185 }
186
187 env->regs[CR_STATUS] |= CR_STATUS_EH;
188 env->regs[CR_STATUS] &= ~(CR_STATUS_PIE | CR_STATUS_U);
189
190 env->regs[CR_EXCEPTION] &= ~(0x1F << 2);
191 env->regs[CR_EXCEPTION] |= (cs->exception_index & 0x1F) << 2;
192
193 env->regs[R_PC] = cpu->exception_addr;
194 break;
195
196 default:
197 cpu_abort(cs, "unhandled exception type=%d\n",
198 cs->exception_index);
199 break;
200 }
201}
202
203hwaddr nios2_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
204{
205 Nios2CPU *cpu = NIOS2_CPU(cs);
206 CPUNios2State *env = &cpu->env;
207 target_ulong vaddr, paddr = 0;
208 Nios2MMULookup lu;
209 unsigned int hit;
210
211 if (cpu->mmu_present && (addr < 0xC0000000)) {
212 hit = mmu_translate(env, &lu, addr, 0, 0);
213 if (hit) {
214 vaddr = addr & TARGET_PAGE_MASK;
215 paddr = lu.paddr + vaddr - lu.vaddr;
216 } else {
217 paddr = -1;
218 qemu_log("cpu_get_phys_page debug MISS: %#" PRIx64 "\n", addr);
219 }
220 } else {
221 paddr = addr & TARGET_PAGE_MASK;
222 }
223
224 return paddr;
225}
226
227void nios2_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
228 MMUAccessType access_type,
229 int mmu_idx, uintptr_t retaddr)
230{
231 Nios2CPU *cpu = NIOS2_CPU(cs);
232 CPUNios2State *env = &cpu->env;
233
234 env->regs[CR_BADADDR] = addr;
235 env->regs[CR_EXCEPTION] = EXCP_UNALIGN << 2;
236 helper_raise_exception(env, EXCP_UNALIGN);
237}
238
239bool nios2_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
240 MMUAccessType access_type, int mmu_idx,
241 bool probe, uintptr_t retaddr)
242{
243 Nios2CPU *cpu = NIOS2_CPU(cs);
244 CPUNios2State *env = &cpu->env;
245 unsigned int excp = EXCP_TLBD;
246 target_ulong vaddr, paddr;
247 Nios2MMULookup lu;
248 unsigned int hit;
249
250 if (!cpu->mmu_present) {
251 /* No MMU */
252 address &= TARGET_PAGE_MASK;
253 tlb_set_page(cs, address, address, PAGE_BITS,
254 mmu_idx, TARGET_PAGE_SIZE);
255 return true;
256 }
257
258 if (MMU_SUPERVISOR_IDX == mmu_idx) {
259 if (address >= 0xC0000000) {
260 /* Kernel physical page - TLB bypassed */
261 address &= TARGET_PAGE_MASK;
262 tlb_set_page(cs, address, address, PAGE_BITS,
263 mmu_idx, TARGET_PAGE_SIZE);
264 return true;
265 }
266 } else {
267 if (address >= 0x80000000) {
268 /* Illegal access from user mode */
269 if (probe) {
270 return false;
271 }
272 cs->exception_index = EXCP_SUPERA;
273 env->regs[CR_BADADDR] = address;
274 cpu_loop_exit_restore(cs, retaddr);
275 }
276 }
277
278 /* Virtual page. */
279 hit = mmu_translate(env, &lu, address, access_type, mmu_idx);
280 if (hit) {
281 vaddr = address & TARGET_PAGE_MASK;
282 paddr = lu.paddr + vaddr - lu.vaddr;
283
284 if (((access_type == MMU_DATA_LOAD) && (lu.prot & PAGE_READ)) ||
285 ((access_type == MMU_DATA_STORE) && (lu.prot & PAGE_WRITE)) ||
286 ((access_type == MMU_INST_FETCH) && (lu.prot & PAGE_EXEC))) {
287 tlb_set_page(cs, vaddr, paddr, lu.prot,
288 mmu_idx, TARGET_PAGE_SIZE);
289 return true;
290 }
291
292 /* Permission violation */
293 excp = (access_type == MMU_DATA_LOAD ? EXCP_TLBR :
294 access_type == MMU_DATA_STORE ? EXCP_TLBW : EXCP_TLBX);
295 }
296
297 if (probe) {
298 return false;
299 }
300
301 if (access_type == MMU_INST_FETCH) {
302 env->regs[CR_TLBMISC] &= ~CR_TLBMISC_D;
303 } else {
304 env->regs[CR_TLBMISC] |= CR_TLBMISC_D;
305 }
306 env->regs[CR_PTEADDR] &= CR_PTEADDR_PTBASE_MASK;
307 env->regs[CR_PTEADDR] |= (address >> 10) & CR_PTEADDR_VPN_MASK;
308 env->mmu.pteaddr_wr = env->regs[CR_PTEADDR];
309
310 cs->exception_index = excp;
311 env->regs[CR_BADADDR] = address;
312 cpu_loop_exit_restore(cs, retaddr);
313}
314#endif /* !CONFIG_USER_ONLY */
315