xref: /openbmc/qemu/target/microblaze/mmu.c (revision 2e1cacfb) 
1 /*
2  *  Microblaze MMU emulation for qemu.
3  *
4  *  Copyright (c) 2009 Edgar E. Iglesias
5  *  Copyright (c) 2009-2012 PetaLogix Qld Pty Ltd.
6  *
7  * This library is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * This library is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include "qemu/osdep.h"
22 #include "qemu/log.h"
23 #include "cpu.h"
24 #include "exec/exec-all.h"
25 #include "exec/page-protection.h"
26 
27 static unsigned int tlb_decode_size(unsigned int f)
28 {
29     static const unsigned int sizes[] = {
30         1 * 1024, 4 * 1024, 16 * 1024, 64 * 1024, 256 * 1024,
31         1 * 1024 * 1024, 4 * 1024 * 1024, 16 * 1024 * 1024
32     };
33     assert(f < ARRAY_SIZE(sizes));
34     return sizes[f];
35 }
36 
37 static void mmu_flush_idx(CPUMBState *env, unsigned int idx)
38 {
39     CPUState *cs = env_cpu(env);
40     MicroBlazeMMU *mmu = &env->mmu;
41     unsigned int tlb_size;
42     uint32_t tlb_tag, end, t;
43 
44     t = mmu->rams[RAM_TAG][idx];
45     if (!(t & TLB_VALID))
46         return;
47 
48     tlb_tag = t & TLB_EPN_MASK;
49     tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
50     end = tlb_tag + tlb_size;
51 
52     while (tlb_tag < end) {
53         tlb_flush_page(cs, tlb_tag);
54         tlb_tag += TARGET_PAGE_SIZE;
55     }
56 }
57 
58 static void mmu_change_pid(CPUMBState *env, unsigned int newpid)
59 {
60     MicroBlazeMMU *mmu = &env->mmu;
61     unsigned int i;
62     uint32_t t;
63 
64     if (newpid & ~0xff)
65         qemu_log_mask(LOG_GUEST_ERROR, "Illegal rpid=%x\n", newpid);
66 
67     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
68         /* Lookup and decode.  */
69         t = mmu->rams[RAM_TAG][i];
70         if (t & TLB_VALID) {
71             if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i]))
72                 mmu_flush_idx(env, i);
73         }
74     }
75 }
76 
77 /* rw - 0 = read, 1 = write, 2 = fetch.  */
78 unsigned int mmu_translate(MicroBlazeCPU *cpu, MicroBlazeMMULookup *lu,
79                            target_ulong vaddr, MMUAccessType rw, int mmu_idx)
80 {
81     MicroBlazeMMU *mmu = &cpu->env.mmu;
82     unsigned int i, hit = 0;
83     unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
84     uint64_t tlb_tag, tlb_rpn, mask;
85     uint32_t tlb_size, t0;
86 
87     lu->err = ERR_MISS;
88     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
89         uint64_t t, d;
90 
91         /* Lookup and decode.  */
92         t = mmu->rams[RAM_TAG][i];
93         if (t & TLB_VALID) {
94             tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
95             if (tlb_size < TARGET_PAGE_SIZE) {
96                 qemu_log_mask(LOG_UNIMP, "%d pages not supported\n", tlb_size);
97                 abort();
98             }
99 
100             mask = ~((uint64_t)tlb_size - 1);
101             tlb_tag = t & TLB_EPN_MASK;
102             if ((vaddr & mask) != (tlb_tag & mask)) {
103                 continue;
104             }
105             if (mmu->tids[i]
106                 && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
107                 continue;
108             }
109 
110             /* Bring in the data part.  */
111             d = mmu->rams[RAM_DATA][i];
112             tlb_ex = d & TLB_EX;
113             tlb_wr = d & TLB_WR;
114 
115             /* Now let's see if there is a zone that overrides the protbits.  */
116             tlb_zsel = (d >> 4) & 0xf;
117             t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
118             t0 &= 0x3;
119 
120             if (tlb_zsel > cpu->cfg.mmu_zones) {
121                 qemu_log_mask(LOG_GUEST_ERROR,
122                               "tlb zone select out of range! %d\n", tlb_zsel);
123                 t0 = 1; /* Ignore.  */
124             }
125 
126             if (cpu->cfg.mmu == 1) {
127                 t0 = 1; /* Zones are disabled.  */
128             }
129 
130             switch (t0) {
131                 case 0:
132                     if (mmu_idx == MMU_USER_IDX)
133                         continue;
134                     break;
135                 case 2:
136                     if (mmu_idx != MMU_USER_IDX) {
137                         tlb_ex = 1;
138                         tlb_wr = 1;
139                     }
140                     break;
141                 case 3:
142                     tlb_ex = 1;
143                     tlb_wr = 1;
144                     break;
145                 default: break;
146             }
147 
148             lu->err = ERR_PROT;
149             lu->prot = PAGE_READ;
150             if (tlb_wr)
151                 lu->prot |= PAGE_WRITE;
152             else if (rw == 1)
153                 goto done;
154             if (tlb_ex)
155                 lu->prot |=PAGE_EXEC;
156             else if (rw == 2) {
157                 goto done;
158             }
159 
160             tlb_rpn = d & TLB_RPN_MASK;
161 
162             lu->vaddr = tlb_tag;
163             lu->paddr = tlb_rpn & cpu->cfg.addr_mask;
164             lu->size = tlb_size;
165             lu->err = ERR_HIT;
166             lu->idx = i;
167             hit = 1;
168             goto done;
169         }
170     }
171 done:
172     qemu_log_mask(CPU_LOG_MMU,
173                   "MMU vaddr=%" PRIx64 " rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
174                   vaddr, rw, tlb_wr, tlb_ex, hit);
175     return hit;
176 }
177 
178 /* Writes/reads to the MMU's special regs end up here.  */
179 uint32_t mmu_read(CPUMBState *env, bool ext, uint32_t rn)
180 {
181     MicroBlazeCPU *cpu = env_archcpu(env);
182     unsigned int i;
183     uint32_t r = 0;
184 
185     if (cpu->cfg.mmu < 2 || !cpu->cfg.mmu_tlb_access) {
186         qemu_log_mask(LOG_GUEST_ERROR, "MMU access on MMU-less system\n");
187         return 0;
188     }
189     if (ext && rn != MMU_R_TLBLO) {
190         qemu_log_mask(LOG_GUEST_ERROR, "Extended access only to TLBLO.\n");
191         return 0;
192     }
193 
194     switch (rn) {
195         /* Reads to HI/LO trig reads from the mmu rams.  */
196         case MMU_R_TLBLO:
197         case MMU_R_TLBHI:
198             if (!(cpu->cfg.mmu_tlb_access & 1)) {
199                 qemu_log_mask(LOG_GUEST_ERROR,
200                               "Invalid access to MMU reg %d\n", rn);
201                 return 0;
202             }
203 
204             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
205             r = extract64(env->mmu.rams[rn & 1][i], ext * 32, 32);
206             if (rn == MMU_R_TLBHI)
207                 env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
208             break;
209         case MMU_R_PID:
210         case MMU_R_ZPR:
211             if (!(cpu->cfg.mmu_tlb_access & 1)) {
212                 qemu_log_mask(LOG_GUEST_ERROR,
213                               "Invalid access to MMU reg %d\n", rn);
214                 return 0;
215             }
216             r = env->mmu.regs[rn];
217             break;
218         case MMU_R_TLBX:
219             r = env->mmu.regs[rn];
220             break;
221         case MMU_R_TLBSX:
222             qemu_log_mask(LOG_GUEST_ERROR, "TLBSX is write-only.\n");
223             break;
224         default:
225             qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
226             break;
227     }
228     qemu_log_mask(CPU_LOG_MMU, "%s rn=%d=%x\n", __func__, rn, r);
229     return r;
230 }
231 
232 void mmu_write(CPUMBState *env, bool ext, uint32_t rn, uint32_t v)
233 {
234     MicroBlazeCPU *cpu = env_archcpu(env);
235     uint64_t tmp64;
236     unsigned int i;
237 
238     qemu_log_mask(CPU_LOG_MMU,
239                   "%s rn=%d=%x old=%x\n", __func__, rn, v,
240                   rn < 3 ? env->mmu.regs[rn] : env->mmu.regs[MMU_R_TLBX]);
241 
242     if (cpu->cfg.mmu < 2 || !cpu->cfg.mmu_tlb_access) {
243         qemu_log_mask(LOG_GUEST_ERROR, "MMU access on MMU-less system\n");
244         return;
245     }
246     if (ext && rn != MMU_R_TLBLO) {
247         qemu_log_mask(LOG_GUEST_ERROR, "Extended access only to TLBLO.\n");
248         return;
249     }
250 
251     switch (rn) {
252         /* Writes to HI/LO trig writes to the mmu rams.  */
253         case MMU_R_TLBLO:
254         case MMU_R_TLBHI:
255             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
256             if (rn == MMU_R_TLBHI) {
257                 if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
258                     qemu_log_mask(LOG_GUEST_ERROR,
259                                   "invalidating index %x at pc=%x\n",
260                                   i, env->pc);
261                 env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
262                 mmu_flush_idx(env, i);
263             }
264             tmp64 = env->mmu.rams[rn & 1][i];
265             env->mmu.rams[rn & 1][i] = deposit64(tmp64, ext * 32, 32, v);
266             break;
267         case MMU_R_ZPR:
268             if (cpu->cfg.mmu_tlb_access <= 1) {
269                 qemu_log_mask(LOG_GUEST_ERROR,
270                               "Invalid access to MMU reg %d\n", rn);
271                 return;
272             }
273 
274             /* Changes to the zone protection reg flush the QEMU TLB.
275                Fortunately, these are very uncommon.  */
276             if (v != env->mmu.regs[rn]) {
277                 tlb_flush(env_cpu(env));
278             }
279             env->mmu.regs[rn] = v;
280             break;
281         case MMU_R_PID:
282             if (cpu->cfg.mmu_tlb_access <= 1) {
283                 qemu_log_mask(LOG_GUEST_ERROR,
284                               "Invalid access to MMU reg %d\n", rn);
285                 return;
286             }
287 
288             if (v != env->mmu.regs[rn]) {
289                 mmu_change_pid(env, v);
290                 env->mmu.regs[rn] = v;
291             }
292             break;
293         case MMU_R_TLBX:
294             /* Bit 31 is read-only.  */
295             env->mmu.regs[rn] = deposit32(env->mmu.regs[rn], 0, 31, v);
296             break;
297         case MMU_R_TLBSX:
298         {
299             MicroBlazeMMULookup lu;
300             int hit;
301 
302             if (cpu->cfg.mmu_tlb_access <= 1) {
303                 qemu_log_mask(LOG_GUEST_ERROR,
304                               "Invalid access to MMU reg %d\n", rn);
305                 return;
306             }
307 
308             hit = mmu_translate(cpu, &lu, v & TLB_EPN_MASK,
309                                 0, cpu_mmu_index(env_cpu(env), false));
310             if (hit) {
311                 env->mmu.regs[MMU_R_TLBX] = lu.idx;
312             } else {
313                 env->mmu.regs[MMU_R_TLBX] |= R_TBLX_MISS_MASK;
314             }
315             break;
316         }
317         default:
318             qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
319             break;
320    }
321 }
322 
323 void mmu_init(MicroBlazeMMU *mmu)
324 {
325     int i;
326     for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) {
327         mmu->regs[i] = 0;
328     }
329 }
330