xref: /openbmc/qemu/target/microblaze/mmu.c (revision af531756) 
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 "cpu.h"
23 #include "exec/exec-all.h"
24 
25 static unsigned int tlb_decode_size(unsigned int f)
26 {
27     static const unsigned int sizes[] = {
28         1 * 1024, 4 * 1024, 16 * 1024, 64 * 1024, 256 * 1024,
29         1 * 1024 * 1024, 4 * 1024 * 1024, 16 * 1024 * 1024
30     };
31     assert(f < ARRAY_SIZE(sizes));
32     return sizes[f];
33 }
34 
35 static void mmu_flush_idx(CPUMBState *env, unsigned int idx)
36 {
37     CPUState *cs = env_cpu(env);
38     MicroBlazeMMU *mmu = &env->mmu;
39     unsigned int tlb_size;
40     uint32_t tlb_tag, end, t;
41 
42     t = mmu->rams[RAM_TAG][idx];
43     if (!(t & TLB_VALID))
44         return;
45 
46     tlb_tag = t & TLB_EPN_MASK;
47     tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
48     end = tlb_tag + tlb_size;
49 
50     while (tlb_tag < end) {
51         tlb_flush_page(cs, tlb_tag);
52         tlb_tag += TARGET_PAGE_SIZE;
53     }
54 }
55 
56 static void mmu_change_pid(CPUMBState *env, unsigned int newpid)
57 {
58     MicroBlazeMMU *mmu = &env->mmu;
59     unsigned int i;
60     uint32_t t;
61 
62     if (newpid & ~0xff)
63         qemu_log_mask(LOG_GUEST_ERROR, "Illegal rpid=%x\n", newpid);
64 
65     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
66         /* Lookup and decode.  */
67         t = mmu->rams[RAM_TAG][i];
68         if (t & TLB_VALID) {
69             if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i]))
70                 mmu_flush_idx(env, i);
71         }
72     }
73 }
74 
75 /* rw - 0 = read, 1 = write, 2 = fetch.  */
76 unsigned int mmu_translate(MicroBlazeCPU *cpu, MicroBlazeMMULookup *lu,
77                            target_ulong vaddr, MMUAccessType rw, int mmu_idx)
78 {
79     MicroBlazeMMU *mmu = &cpu->env.mmu;
80     unsigned int i, hit = 0;
81     unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
82     uint64_t tlb_tag, tlb_rpn, mask;
83     uint32_t tlb_size, t0;
84 
85     lu->err = ERR_MISS;
86     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
87         uint64_t t, d;
88 
89         /* Lookup and decode.  */
90         t = mmu->rams[RAM_TAG][i];
91         if (t & TLB_VALID) {
92             tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
93             if (tlb_size < TARGET_PAGE_SIZE) {
94                 qemu_log_mask(LOG_UNIMP, "%d pages not supported\n", tlb_size);
95                 abort();
96             }
97 
98             mask = ~((uint64_t)tlb_size - 1);
99             tlb_tag = t & TLB_EPN_MASK;
100             if ((vaddr & mask) != (tlb_tag & mask)) {
101                 continue;
102             }
103             if (mmu->tids[i]
104                 && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
105                 continue;
106             }
107 
108             /* Bring in the data part.  */
109             d = mmu->rams[RAM_DATA][i];
110             tlb_ex = d & TLB_EX;
111             tlb_wr = d & TLB_WR;
112 
113             /* Now let's see if there is a zone that overrides the protbits.  */
114             tlb_zsel = (d >> 4) & 0xf;
115             t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
116             t0 &= 0x3;
117 
118             if (tlb_zsel > cpu->cfg.mmu_zones) {
119                 qemu_log_mask(LOG_GUEST_ERROR,
120                               "tlb zone select out of range! %d\n", tlb_zsel);
121                 t0 = 1; /* Ignore.  */
122             }
123 
124             if (cpu->cfg.mmu == 1) {
125                 t0 = 1; /* Zones are disabled.  */
126             }
127 
128             switch (t0) {
129                 case 0:
130                     if (mmu_idx == MMU_USER_IDX)
131                         continue;
132                     break;
133                 case 2:
134                     if (mmu_idx != MMU_USER_IDX) {
135                         tlb_ex = 1;
136                         tlb_wr = 1;
137                     }
138                     break;
139                 case 3:
140                     tlb_ex = 1;
141                     tlb_wr = 1;
142                     break;
143                 default: break;
144             }
145 
146             lu->err = ERR_PROT;
147             lu->prot = PAGE_READ;
148             if (tlb_wr)
149                 lu->prot |= PAGE_WRITE;
150             else if (rw == 1)
151                 goto done;
152             if (tlb_ex)
153                 lu->prot |=PAGE_EXEC;
154             else if (rw == 2) {
155                 goto done;
156             }
157 
158             tlb_rpn = d & TLB_RPN_MASK;
159 
160             lu->vaddr = tlb_tag;
161             lu->paddr = tlb_rpn & cpu->cfg.addr_mask;
162             lu->size = tlb_size;
163             lu->err = ERR_HIT;
164             lu->idx = i;
165             hit = 1;
166             goto done;
167         }
168     }
169 done:
170     qemu_log_mask(CPU_LOG_MMU,
171                   "MMU vaddr=%" PRIx64 " rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
172                   vaddr, rw, tlb_wr, tlb_ex, hit);
173     return hit;
174 }
175 
176 /* Writes/reads to the MMU's special regs end up here.  */
177 uint32_t mmu_read(CPUMBState *env, bool ext, uint32_t rn)
178 {
179     MicroBlazeCPU *cpu = env_archcpu(env);
180     unsigned int i;
181     uint32_t r = 0;
182 
183     if (cpu->cfg.mmu < 2 || !cpu->cfg.mmu_tlb_access) {
184         qemu_log_mask(LOG_GUEST_ERROR, "MMU access on MMU-less system\n");
185         return 0;
186     }
187     if (ext && rn != MMU_R_TLBLO) {
188         qemu_log_mask(LOG_GUEST_ERROR, "Extended access only to TLBLO.\n");
189         return 0;
190     }
191 
192     switch (rn) {
193         /* Reads to HI/LO trig reads from the mmu rams.  */
194         case MMU_R_TLBLO:
195         case MMU_R_TLBHI:
196             if (!(cpu->cfg.mmu_tlb_access & 1)) {
197                 qemu_log_mask(LOG_GUEST_ERROR,
198                               "Invalid access to MMU reg %d\n", rn);
199                 return 0;
200             }
201 
202             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
203             r = extract64(env->mmu.rams[rn & 1][i], ext * 32, 32);
204             if (rn == MMU_R_TLBHI)
205                 env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
206             break;
207         case MMU_R_PID:
208         case MMU_R_ZPR:
209             if (!(cpu->cfg.mmu_tlb_access & 1)) {
210                 qemu_log_mask(LOG_GUEST_ERROR,
211                               "Invalid access to MMU reg %d\n", rn);
212                 return 0;
213             }
214             r = env->mmu.regs[rn];
215             break;
216         case MMU_R_TLBX:
217             r = env->mmu.regs[rn];
218             break;
219         case MMU_R_TLBSX:
220             qemu_log_mask(LOG_GUEST_ERROR, "TLBSX is write-only.\n");
221             break;
222         default:
223             qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
224             break;
225     }
226     qemu_log_mask(CPU_LOG_MMU, "%s rn=%d=%x\n", __func__, rn, r);
227     return r;
228 }
229 
230 void mmu_write(CPUMBState *env, bool ext, uint32_t rn, uint32_t v)
231 {
232     MicroBlazeCPU *cpu = env_archcpu(env);
233     uint64_t tmp64;
234     unsigned int i;
235 
236     qemu_log_mask(CPU_LOG_MMU,
237                   "%s rn=%d=%x old=%x\n", __func__, rn, v,
238                   rn < 3 ? env->mmu.regs[rn] : env->mmu.regs[MMU_R_TLBX]);
239 
240     if (cpu->cfg.mmu < 2 || !cpu->cfg.mmu_tlb_access) {
241         qemu_log_mask(LOG_GUEST_ERROR, "MMU access on MMU-less system\n");
242         return;
243     }
244     if (ext && rn != MMU_R_TLBLO) {
245         qemu_log_mask(LOG_GUEST_ERROR, "Extended access only to TLBLO.\n");
246         return;
247     }
248 
249     switch (rn) {
250         /* Writes to HI/LO trig writes to the mmu rams.  */
251         case MMU_R_TLBLO:
252         case MMU_R_TLBHI:
253             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
254             if (rn == MMU_R_TLBHI) {
255                 if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
256                     qemu_log_mask(LOG_GUEST_ERROR,
257                                   "invalidating index %x at pc=%x\n",
258                                   i, env->pc);
259                 env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
260                 mmu_flush_idx(env, i);
261             }
262             tmp64 = env->mmu.rams[rn & 1][i];
263             env->mmu.rams[rn & 1][i] = deposit64(tmp64, ext * 32, 32, v);
264             break;
265         case MMU_R_ZPR:
266             if (cpu->cfg.mmu_tlb_access <= 1) {
267                 qemu_log_mask(LOG_GUEST_ERROR,
268                               "Invalid access to MMU reg %d\n", rn);
269                 return;
270             }
271 
272             /* Changes to the zone protection reg flush the QEMU TLB.
273                Fortunately, these are very uncommon.  */
274             if (v != env->mmu.regs[rn]) {
275                 tlb_flush(env_cpu(env));
276             }
277             env->mmu.regs[rn] = v;
278             break;
279         case MMU_R_PID:
280             if (cpu->cfg.mmu_tlb_access <= 1) {
281                 qemu_log_mask(LOG_GUEST_ERROR,
282                               "Invalid access to MMU reg %d\n", rn);
283                 return;
284             }
285 
286             if (v != env->mmu.regs[rn]) {
287                 mmu_change_pid(env, v);
288                 env->mmu.regs[rn] = v;
289             }
290             break;
291         case MMU_R_TLBX:
292             /* Bit 31 is read-only.  */
293             env->mmu.regs[rn] = deposit32(env->mmu.regs[rn], 0, 31, v);
294             break;
295         case MMU_R_TLBSX:
296         {
297             MicroBlazeMMULookup lu;
298             int hit;
299 
300             if (cpu->cfg.mmu_tlb_access <= 1) {
301                 qemu_log_mask(LOG_GUEST_ERROR,
302                               "Invalid access to MMU reg %d\n", rn);
303                 return;
304             }
305 
306             hit = mmu_translate(cpu, &lu, v & TLB_EPN_MASK,
307                                 0, cpu_mmu_index(env, false));
308             if (hit) {
309                 env->mmu.regs[MMU_R_TLBX] = lu.idx;
310             } else {
311                 env->mmu.regs[MMU_R_TLBX] |= R_TBLX_MISS_MASK;
312             }
313             break;
314         }
315         default:
316             qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
317             break;
318    }
319 }
320 
321 void mmu_init(MicroBlazeMMU *mmu)
322 {
323     int i;
324     for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) {
325         mmu->regs[i] = 0;
326     }
327 }
328