xref: /openbmc/qemu/target/ppc/mmu-hash32.c (revision ef17dd6a)
1 /*
2  *  PowerPC MMU, TLB and BAT emulation helpers for QEMU.
3  *
4  *  Copyright (c) 2003-2007 Jocelyn Mayer
5  *  Copyright (c) 2013 David Gibson, IBM Corporation
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 #include "sysemu/kvm.h"
25 #include "kvm_ppc.h"
26 #include "internal.h"
27 #include "mmu-hash32.h"
28 #include "mmu-books.h"
29 #include "exec/log.h"
30 
31 /* #define DEBUG_BATS */
32 
33 #ifdef DEBUG_BATS
34 #  define LOG_BATS(...) qemu_log_mask(CPU_LOG_MMU, __VA_ARGS__)
35 #else
36 #  define LOG_BATS(...) do { } while (0)
37 #endif
38 
39 struct mmu_ctx_hash32 {
40     hwaddr raddr;      /* Real address              */
41     int prot;                      /* Protection bits           */
42     int key;                       /* Access key                */
43 };
44 
45 static int ppc_hash32_pp_prot(int key, int pp, int nx)
46 {
47     int prot;
48 
49     if (key == 0) {
50         switch (pp) {
51         case 0x0:
52         case 0x1:
53         case 0x2:
54             prot = PAGE_READ | PAGE_WRITE;
55             break;
56 
57         case 0x3:
58             prot = PAGE_READ;
59             break;
60 
61         default:
62             abort();
63         }
64     } else {
65         switch (pp) {
66         case 0x0:
67             prot = 0;
68             break;
69 
70         case 0x1:
71         case 0x3:
72             prot = PAGE_READ;
73             break;
74 
75         case 0x2:
76             prot = PAGE_READ | PAGE_WRITE;
77             break;
78 
79         default:
80             abort();
81         }
82     }
83     if (nx == 0) {
84         prot |= PAGE_EXEC;
85     }
86 
87     return prot;
88 }
89 
90 static int ppc_hash32_pte_prot(int mmu_idx,
91                                target_ulong sr, ppc_hash_pte32_t pte)
92 {
93     unsigned pp, key;
94 
95     key = !!(mmuidx_pr(mmu_idx) ? (sr & SR32_KP) : (sr & SR32_KS));
96     pp = pte.pte1 & HPTE32_R_PP;
97 
98     return ppc_hash32_pp_prot(key, pp, !!(sr & SR32_NX));
99 }
100 
101 static target_ulong hash32_bat_size(int mmu_idx,
102                                     target_ulong batu, target_ulong batl)
103 {
104     if ((mmuidx_pr(mmu_idx) && !(batu & BATU32_VP))
105         || (!mmuidx_pr(mmu_idx) && !(batu & BATU32_VS))) {
106         return 0;
107     }
108 
109     return BATU32_BEPI & ~((batu & BATU32_BL) << 15);
110 }
111 
112 static int hash32_bat_prot(PowerPCCPU *cpu,
113                            target_ulong batu, target_ulong batl)
114 {
115     int pp, prot;
116 
117     prot = 0;
118     pp = batl & BATL32_PP;
119     if (pp != 0) {
120         prot = PAGE_READ | PAGE_EXEC;
121         if (pp == 0x2) {
122             prot |= PAGE_WRITE;
123         }
124     }
125     return prot;
126 }
127 
128 static hwaddr ppc_hash32_bat_lookup(PowerPCCPU *cpu, target_ulong ea,
129                                     MMUAccessType access_type, int *prot,
130                                     int mmu_idx)
131 {
132     CPUPPCState *env = &cpu->env;
133     target_ulong *BATlt, *BATut;
134     bool ifetch = access_type == MMU_INST_FETCH;
135     int i;
136 
137     LOG_BATS("%s: %cBAT v " TARGET_FMT_lx "\n", __func__,
138              ifetch ? 'I' : 'D', ea);
139     if (ifetch) {
140         BATlt = env->IBAT[1];
141         BATut = env->IBAT[0];
142     } else {
143         BATlt = env->DBAT[1];
144         BATut = env->DBAT[0];
145     }
146     for (i = 0; i < env->nb_BATs; i++) {
147         target_ulong batu = BATut[i];
148         target_ulong batl = BATlt[i];
149         target_ulong mask;
150 
151         mask = hash32_bat_size(mmu_idx, batu, batl);
152         LOG_BATS("%s: %cBAT%d v " TARGET_FMT_lx " BATu " TARGET_FMT_lx
153                  " BATl " TARGET_FMT_lx "\n", __func__,
154                  ifetch ? 'I' : 'D', i, ea, batu, batl);
155 
156         if (mask && ((ea & mask) == (batu & BATU32_BEPI))) {
157             hwaddr raddr = (batl & mask) | (ea & ~mask);
158 
159             *prot = hash32_bat_prot(cpu, batu, batl);
160 
161             return raddr & TARGET_PAGE_MASK;
162         }
163     }
164 
165     /* No hit */
166 #if defined(DEBUG_BATS)
167     if (qemu_log_enabled()) {
168         target_ulong *BATu, *BATl;
169         target_ulong BEPIl, BEPIu, bl;
170 
171         LOG_BATS("no BAT match for " TARGET_FMT_lx ":\n", ea);
172         for (i = 0; i < 4; i++) {
173             BATu = &BATut[i];
174             BATl = &BATlt[i];
175             BEPIu = *BATu & BATU32_BEPIU;
176             BEPIl = *BATu & BATU32_BEPIL;
177             bl = (*BATu & 0x00001FFC) << 15;
178             LOG_BATS("%s: %cBAT%d v " TARGET_FMT_lx " BATu " TARGET_FMT_lx
179                      " BATl " TARGET_FMT_lx "\n\t" TARGET_FMT_lx " "
180                      TARGET_FMT_lx " " TARGET_FMT_lx "\n",
181                      __func__, ifetch ? 'I' : 'D', i, ea,
182                      *BATu, *BATl, BEPIu, BEPIl, bl);
183         }
184     }
185 #endif
186 
187     return -1;
188 }
189 
190 static bool ppc_hash32_direct_store(PowerPCCPU *cpu, target_ulong sr,
191                                     target_ulong eaddr,
192                                     MMUAccessType access_type,
193                                     hwaddr *raddr, int *prot, int mmu_idx,
194                                     bool guest_visible)
195 {
196     CPUState *cs = CPU(cpu);
197     CPUPPCState *env = &cpu->env;
198     int key = !!(mmuidx_pr(mmu_idx) ? (sr & SR32_KP) : (sr & SR32_KS));
199 
200     qemu_log_mask(CPU_LOG_MMU, "direct store...\n");
201 
202     if (access_type == MMU_INST_FETCH) {
203         /* No code fetch is allowed in direct-store areas */
204         if (guest_visible) {
205             cs->exception_index = POWERPC_EXCP_ISI;
206             env->error_code = 0x10000000;
207         }
208         return false;
209     }
210 
211     /*
212      * From ppc_cpu_get_phys_page_debug, env->access_type is not set.
213      * Assume ACCESS_INT for that case.
214      */
215     switch (guest_visible ? env->access_type : ACCESS_INT) {
216     case ACCESS_INT:
217         /* Integer load/store : only access allowed */
218         break;
219     case ACCESS_FLOAT:
220         /* Floating point load/store */
221         cs->exception_index = POWERPC_EXCP_ALIGN;
222         env->error_code = POWERPC_EXCP_ALIGN_FP;
223         env->spr[SPR_DAR] = eaddr;
224         return false;
225     case ACCESS_RES:
226         /* lwarx, ldarx or srwcx. */
227         env->error_code = 0;
228         env->spr[SPR_DAR] = eaddr;
229         if (access_type == MMU_DATA_STORE) {
230             env->spr[SPR_DSISR] = 0x06000000;
231         } else {
232             env->spr[SPR_DSISR] = 0x04000000;
233         }
234         return false;
235     case ACCESS_CACHE:
236         /*
237          * dcba, dcbt, dcbtst, dcbf, dcbi, dcbst, dcbz, or icbi
238          *
239          * Should make the instruction do no-op.  As it already do
240          * no-op, it's quite easy :-)
241          */
242         *raddr = eaddr;
243         return true;
244     case ACCESS_EXT:
245         /* eciwx or ecowx */
246         cs->exception_index = POWERPC_EXCP_DSI;
247         env->error_code = 0;
248         env->spr[SPR_DAR] = eaddr;
249         if (access_type == MMU_DATA_STORE) {
250             env->spr[SPR_DSISR] = 0x06100000;
251         } else {
252             env->spr[SPR_DSISR] = 0x04100000;
253         }
254         return false;
255     default:
256         cpu_abort(cs, "ERROR: insn should not need address translation\n");
257     }
258 
259     *prot = key ? PAGE_READ | PAGE_WRITE : PAGE_READ;
260     if (*prot & prot_for_access_type(access_type)) {
261         *raddr = eaddr;
262         return true;
263     }
264 
265     if (guest_visible) {
266         cs->exception_index = POWERPC_EXCP_DSI;
267         env->error_code = 0;
268         env->spr[SPR_DAR] = eaddr;
269         if (access_type == MMU_DATA_STORE) {
270             env->spr[SPR_DSISR] = 0x0a000000;
271         } else {
272             env->spr[SPR_DSISR] = 0x08000000;
273         }
274     }
275     return false;
276 }
277 
278 hwaddr get_pteg_offset32(PowerPCCPU *cpu, hwaddr hash)
279 {
280     target_ulong mask = ppc_hash32_hpt_mask(cpu);
281 
282     return (hash * HASH_PTEG_SIZE_32) & mask;
283 }
284 
285 static hwaddr ppc_hash32_pteg_search(PowerPCCPU *cpu, hwaddr pteg_off,
286                                      bool secondary, target_ulong ptem,
287                                      ppc_hash_pte32_t *pte)
288 {
289     hwaddr pte_offset = pteg_off;
290     target_ulong pte0, pte1;
291     int i;
292 
293     for (i = 0; i < HPTES_PER_GROUP; i++) {
294         pte0 = ppc_hash32_load_hpte0(cpu, pte_offset);
295         /*
296          * pte0 contains the valid bit and must be read before pte1,
297          * otherwise we might see an old pte1 with a new valid bit and
298          * thus an inconsistent hpte value
299          */
300         smp_rmb();
301         pte1 = ppc_hash32_load_hpte1(cpu, pte_offset);
302 
303         if ((pte0 & HPTE32_V_VALID)
304             && (secondary == !!(pte0 & HPTE32_V_SECONDARY))
305             && HPTE32_V_COMPARE(pte0, ptem)) {
306             pte->pte0 = pte0;
307             pte->pte1 = pte1;
308             return pte_offset;
309         }
310 
311         pte_offset += HASH_PTE_SIZE_32;
312     }
313 
314     return -1;
315 }
316 
317 static void ppc_hash32_set_r(PowerPCCPU *cpu, hwaddr pte_offset, uint32_t pte1)
318 {
319     target_ulong base = ppc_hash32_hpt_base(cpu);
320     hwaddr offset = pte_offset + 6;
321 
322     /* The HW performs a non-atomic byte update */
323     stb_phys(CPU(cpu)->as, base + offset, ((pte1 >> 8) & 0xff) | 0x01);
324 }
325 
326 static void ppc_hash32_set_c(PowerPCCPU *cpu, hwaddr pte_offset, uint64_t pte1)
327 {
328     target_ulong base = ppc_hash32_hpt_base(cpu);
329     hwaddr offset = pte_offset + 7;
330 
331     /* The HW performs a non-atomic byte update */
332     stb_phys(CPU(cpu)->as, base + offset, (pte1 & 0xff) | 0x80);
333 }
334 
335 static hwaddr ppc_hash32_htab_lookup(PowerPCCPU *cpu,
336                                      target_ulong sr, target_ulong eaddr,
337                                      ppc_hash_pte32_t *pte)
338 {
339     hwaddr pteg_off, pte_offset;
340     hwaddr hash;
341     uint32_t vsid, pgidx, ptem;
342 
343     vsid = sr & SR32_VSID;
344     pgidx = (eaddr & ~SEGMENT_MASK_256M) >> TARGET_PAGE_BITS;
345     hash = vsid ^ pgidx;
346     ptem = (vsid << 7) | (pgidx >> 10);
347 
348     /* Page address translation */
349     qemu_log_mask(CPU_LOG_MMU, "htab_base " TARGET_FMT_plx
350             " htab_mask " TARGET_FMT_plx
351             " hash " TARGET_FMT_plx "\n",
352             ppc_hash32_hpt_base(cpu), ppc_hash32_hpt_mask(cpu), hash);
353 
354     /* Primary PTEG lookup */
355     qemu_log_mask(CPU_LOG_MMU, "0 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
356             " vsid=%" PRIx32 " ptem=%" PRIx32
357             " hash=" TARGET_FMT_plx "\n",
358             ppc_hash32_hpt_base(cpu), ppc_hash32_hpt_mask(cpu),
359             vsid, ptem, hash);
360     pteg_off = get_pteg_offset32(cpu, hash);
361     pte_offset = ppc_hash32_pteg_search(cpu, pteg_off, 0, ptem, pte);
362     if (pte_offset == -1) {
363         /* Secondary PTEG lookup */
364         qemu_log_mask(CPU_LOG_MMU, "1 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
365                 " vsid=%" PRIx32 " api=%" PRIx32
366                 " hash=" TARGET_FMT_plx "\n", ppc_hash32_hpt_base(cpu),
367                 ppc_hash32_hpt_mask(cpu), vsid, ptem, ~hash);
368         pteg_off = get_pteg_offset32(cpu, ~hash);
369         pte_offset = ppc_hash32_pteg_search(cpu, pteg_off, 1, ptem, pte);
370     }
371 
372     return pte_offset;
373 }
374 
375 static hwaddr ppc_hash32_pte_raddr(target_ulong sr, ppc_hash_pte32_t pte,
376                                    target_ulong eaddr)
377 {
378     hwaddr rpn = pte.pte1 & HPTE32_R_RPN;
379     hwaddr mask = ~TARGET_PAGE_MASK;
380 
381     return (rpn & ~mask) | (eaddr & mask);
382 }
383 
384 bool ppc_hash32_xlate(PowerPCCPU *cpu, vaddr eaddr, MMUAccessType access_type,
385                       hwaddr *raddrp, int *psizep, int *protp, int mmu_idx,
386                       bool guest_visible)
387 {
388     CPUState *cs = CPU(cpu);
389     CPUPPCState *env = &cpu->env;
390     target_ulong sr;
391     hwaddr pte_offset;
392     ppc_hash_pte32_t pte;
393     int prot;
394     int need_prot;
395     hwaddr raddr;
396 
397     /* There are no hash32 large pages. */
398     *psizep = TARGET_PAGE_BITS;
399 
400     /* 1. Handle real mode accesses */
401     if (mmuidx_real(mmu_idx)) {
402         /* Translation is off */
403         *raddrp = eaddr;
404         *protp = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
405         return true;
406     }
407 
408     need_prot = prot_for_access_type(access_type);
409 
410     /* 2. Check Block Address Translation entries (BATs) */
411     if (env->nb_BATs != 0) {
412         raddr = ppc_hash32_bat_lookup(cpu, eaddr, access_type, protp, mmu_idx);
413         if (raddr != -1) {
414             if (need_prot & ~*protp) {
415                 if (guest_visible) {
416                     if (access_type == MMU_INST_FETCH) {
417                         cs->exception_index = POWERPC_EXCP_ISI;
418                         env->error_code = 0x08000000;
419                     } else {
420                         cs->exception_index = POWERPC_EXCP_DSI;
421                         env->error_code = 0;
422                         env->spr[SPR_DAR] = eaddr;
423                         if (access_type == MMU_DATA_STORE) {
424                             env->spr[SPR_DSISR] = 0x0a000000;
425                         } else {
426                             env->spr[SPR_DSISR] = 0x08000000;
427                         }
428                     }
429                 }
430                 return false;
431             }
432             *raddrp = raddr;
433             return true;
434         }
435     }
436 
437     /* 3. Look up the Segment Register */
438     sr = env->sr[eaddr >> 28];
439 
440     /* 4. Handle direct store segments */
441     if (sr & SR32_T) {
442         return ppc_hash32_direct_store(cpu, sr, eaddr, access_type,
443                                        raddrp, protp, mmu_idx, guest_visible);
444     }
445 
446     /* 5. Check for segment level no-execute violation */
447     if (access_type == MMU_INST_FETCH && (sr & SR32_NX)) {
448         if (guest_visible) {
449             cs->exception_index = POWERPC_EXCP_ISI;
450             env->error_code = 0x10000000;
451         }
452         return false;
453     }
454 
455     /* 6. Locate the PTE in the hash table */
456     pte_offset = ppc_hash32_htab_lookup(cpu, sr, eaddr, &pte);
457     if (pte_offset == -1) {
458         if (guest_visible) {
459             if (access_type == MMU_INST_FETCH) {
460                 cs->exception_index = POWERPC_EXCP_ISI;
461                 env->error_code = 0x40000000;
462             } else {
463                 cs->exception_index = POWERPC_EXCP_DSI;
464                 env->error_code = 0;
465                 env->spr[SPR_DAR] = eaddr;
466                 if (access_type == MMU_DATA_STORE) {
467                     env->spr[SPR_DSISR] = 0x42000000;
468                 } else {
469                     env->spr[SPR_DSISR] = 0x40000000;
470                 }
471             }
472         }
473         return false;
474     }
475     qemu_log_mask(CPU_LOG_MMU,
476                 "found PTE at offset %08" HWADDR_PRIx "\n", pte_offset);
477 
478     /* 7. Check access permissions */
479 
480     prot = ppc_hash32_pte_prot(mmu_idx, sr, pte);
481 
482     if (need_prot & ~prot) {
483         /* Access right violation */
484         qemu_log_mask(CPU_LOG_MMU, "PTE access rejected\n");
485         if (guest_visible) {
486             if (access_type == MMU_INST_FETCH) {
487                 cs->exception_index = POWERPC_EXCP_ISI;
488                 env->error_code = 0x08000000;
489             } else {
490                 cs->exception_index = POWERPC_EXCP_DSI;
491                 env->error_code = 0;
492                 env->spr[SPR_DAR] = eaddr;
493                 if (access_type == MMU_DATA_STORE) {
494                     env->spr[SPR_DSISR] = 0x0a000000;
495                 } else {
496                     env->spr[SPR_DSISR] = 0x08000000;
497                 }
498             }
499         }
500         return false;
501     }
502 
503     qemu_log_mask(CPU_LOG_MMU, "PTE access granted !\n");
504 
505     /* 8. Update PTE referenced and changed bits if necessary */
506 
507     if (!(pte.pte1 & HPTE32_R_R)) {
508         ppc_hash32_set_r(cpu, pte_offset, pte.pte1);
509     }
510     if (!(pte.pte1 & HPTE32_R_C)) {
511         if (access_type == MMU_DATA_STORE) {
512             ppc_hash32_set_c(cpu, pte_offset, pte.pte1);
513         } else {
514             /*
515              * Treat the page as read-only for now, so that a later write
516              * will pass through this function again to set the C bit
517              */
518             prot &= ~PAGE_WRITE;
519         }
520      }
521 
522     /* 9. Determine the real address from the PTE */
523 
524     *raddrp = ppc_hash32_pte_raddr(sr, pte, eaddr);
525     *protp = prot;
526     return true;
527 }
528