1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * TLB Management (flush/create/diagnostics) for MMUv3 and MMUv4
4 *
5 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
6 *
7 */
8
9 #include <linux/module.h>
10 #include <linux/bug.h>
11 #include <linux/mm_types.h>
12
13 #include <asm/arcregs.h>
14 #include <asm/setup.h>
15 #include <asm/mmu_context.h>
16 #include <asm/mmu.h>
17
18 /* A copy of the ASID from the PID reg is kept in asid_cache */
19 DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;
20
21 static struct cpuinfo_arc_mmu {
22 unsigned int ver, pg_sz_k, s_pg_sz_m, pae, sets, ways;
23 } mmuinfo;
24
25 /*
26 * Utility Routine to erase a J-TLB entry
27 * Caller needs to setup Index Reg (manually or via getIndex)
28 */
29 static inline void __tlb_entry_erase(void)
30 {
31 write_aux_reg(ARC_REG_TLBPD1, 0);
32
33 if (is_pae40_enabled())
34 write_aux_reg(ARC_REG_TLBPD1HI, 0);
35
36 write_aux_reg(ARC_REG_TLBPD0, 0);
37 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
38 }
39
40 static void utlb_invalidate(void)
41 {
42 write_aux_reg(ARC_REG_TLBCOMMAND, TLBIVUTLB);
43 }
44
45 #ifdef CONFIG_ARC_MMU_V3
46
47 static inline unsigned int tlb_entry_lkup(unsigned long vaddr_n_asid)
48 {
49 unsigned int idx;
50
51 write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid);
52
53 write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);
54 idx = read_aux_reg(ARC_REG_TLBINDEX);
55
56 return idx;
57 }
58
59 static void tlb_entry_erase(unsigned int vaddr_n_asid)
60 {
61 unsigned int idx;
62
63 /* Locate the TLB entry for this vaddr + ASID */
64 idx = tlb_entry_lkup(vaddr_n_asid);
65
66 /* No error means entry found, zero it out */
67 if (likely(!(idx & TLB_LKUP_ERR))) {
68 __tlb_entry_erase();
69 } else {
70 /* Duplicate entry error */
71 WARN(idx == TLB_DUP_ERR, "Probe returned Dup PD for %x\n",
72 vaddr_n_asid);
73 }
74 }
75
76 static void tlb_entry_insert(unsigned int pd0, phys_addr_t pd1)
77 {
78 unsigned int idx;
79
80 /*
81 * First verify if entry for this vaddr+ASID already exists
82 * This also sets up PD0 (vaddr, ASID..) for final commit
83 */
84 idx = tlb_entry_lkup(pd0);
85
86 /*
87 * If Not already present get a free slot from MMU.
88 * Otherwise, Probe would have located the entry and set INDEX Reg
89 * with existing location. This will cause Write CMD to over-write
90 * existing entry with new PD0 and PD1
91 */
92 if (likely(idx & TLB_LKUP_ERR))
93 write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);
94
95 /* setup the other half of TLB entry (pfn, rwx..) */
96 write_aux_reg(ARC_REG_TLBPD1, pd1);
97
98 /*
99 * Commit the Entry to MMU
100 * It doesn't sound safe to use the TLBWriteNI cmd here
101 * which doesn't flush uTLBs. I'd rather be safe than sorry.
102 */
103 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
104 }
105
106 #else /* MMUv4 */
107
108 static void tlb_entry_erase(unsigned int vaddr_n_asid)
109 {
110 write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid | _PAGE_PRESENT);
111 write_aux_reg(ARC_REG_TLBCOMMAND, TLBDeleteEntry);
112 }
113
114 static void tlb_entry_insert(unsigned int pd0, phys_addr_t pd1)
115 {
116 write_aux_reg(ARC_REG_TLBPD0, pd0);
117
118 if (!is_pae40_enabled()) {
119 write_aux_reg(ARC_REG_TLBPD1, pd1);
120 } else {
121 write_aux_reg(ARC_REG_TLBPD1, pd1 & 0xFFFFFFFF);
122 write_aux_reg(ARC_REG_TLBPD1HI, (u64)pd1 >> 32);
123 }
124
125 write_aux_reg(ARC_REG_TLBCOMMAND, TLBInsertEntry);
126 }
127
128 #endif
129
130 /*
131 * Un-conditionally (without lookup) erase the entire MMU contents
132 */
133
134 noinline void local_flush_tlb_all(void)
135 {
136 struct cpuinfo_arc_mmu *mmu = &mmuinfo;
137 unsigned long flags;
138 unsigned int entry;
139 int num_tlb = mmu->sets * mmu->ways;
140
141 local_irq_save(flags);
142
143 /* Load PD0 and PD1 with template for a Blank Entry */
144 write_aux_reg(ARC_REG_TLBPD1, 0);
145
146 if (is_pae40_enabled())
147 write_aux_reg(ARC_REG_TLBPD1HI, 0);
148
149 write_aux_reg(ARC_REG_TLBPD0, 0);
150
151 for (entry = 0; entry < num_tlb; entry++) {
152 /* write this entry to the TLB */
153 write_aux_reg(ARC_REG_TLBINDEX, entry);
154 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI);
155 }
156
157 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
158 const int stlb_idx = 0x800;
159
160 /* Blank sTLB entry */
161 write_aux_reg(ARC_REG_TLBPD0, _PAGE_HW_SZ);
162
163 for (entry = stlb_idx; entry < stlb_idx + 16; entry++) {
164 write_aux_reg(ARC_REG_TLBINDEX, entry);
165 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI);
166 }
167 }
168
169 utlb_invalidate();
170
171 local_irq_restore(flags);
172 }
173
174 /*
175 * Flush the entire MM for userland. The fastest way is to move to Next ASID
176 */
177 noinline void local_flush_tlb_mm(struct mm_struct *mm)
178 {
179 /*
180 * Small optimisation courtesy IA64
181 * flush_mm called during fork,exit,munmap etc, multiple times as well.
182 * Only for fork( ) do we need to move parent to a new MMU ctxt,
183 * all other cases are NOPs, hence this check.
184 */
185 if (atomic_read(&mm->mm_users) == 0)
186 return;
187
188 /*
189 * - Move to a new ASID, but only if the mm is still wired in
190 * (Android Binder ended up calling this for vma->mm != tsk->mm,
191 * causing h/w - s/w ASID to get out of sync)
192 * - Also get_new_mmu_context() new implementation allocates a new
193 * ASID only if it is not allocated already - so unallocate first
194 */
195 destroy_context(mm);
196 if (current->mm == mm)
197 get_new_mmu_context(mm);
198 }
199
200 /*
201 * Flush a Range of TLB entries for userland.
202 * @start is inclusive, while @end is exclusive
203 * Difference between this and Kernel Range Flush is
204 * -Here the fastest way (if range is too large) is to move to next ASID
205 * without doing any explicit Shootdown
206 * -In case of kernel Flush, entry has to be shot down explicitly
207 */
208 void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
209 unsigned long end)
210 {
211 const unsigned int cpu = smp_processor_id();
212 unsigned long flags;
213
214 /* If range @start to @end is more than 32 TLB entries deep,
215 * it's better to move to a new ASID rather than searching for
216 * individual entries and then shooting them down
217 *
218 * The calc above is rough, doesn't account for unaligned parts,
219 * since this is heuristics based anyways
220 */
221 if (unlikely((end - start) >= PAGE_SIZE * 32)) {
222 local_flush_tlb_mm(vma->vm_mm);
223 return;
224 }
225
226 /*
227 * @start moved to page start: this alone suffices for checking
228 * loop end condition below, w/o need for aligning @end to end
229 * e.g. 2000 to 4001 will anyhow loop twice
230 */
231 start &= PAGE_MASK;
232
233 local_irq_save(flags);
234
235 if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
236 while (start < end) {
237 tlb_entry_erase(start | hw_pid(vma->vm_mm, cpu));
238 start += PAGE_SIZE;
239 }
240 }
241
242 local_irq_restore(flags);
243 }
244
245 /* Flush the kernel TLB entries - vmalloc/modules (Global from MMU perspective)
246 * @start, @end interpreted as kvaddr
247 * Interestingly, shared TLB entries can also be flushed using just
248 * @start,@end alone (interpreted as user vaddr), although technically SASID
249 * is also needed. However our smart TLbProbe lookup takes care of that.
250 */
251 void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
252 {
253 unsigned long flags;
254
255 /* exactly same as above, except for TLB entry not taking ASID */
256
257 if (unlikely((end - start) >= PAGE_SIZE * 32)) {
258 local_flush_tlb_all();
259 return;
260 }
261
262 start &= PAGE_MASK;
263
264 local_irq_save(flags);
265 while (start < end) {
266 tlb_entry_erase(start);
267 start += PAGE_SIZE;
268 }
269
270 local_irq_restore(flags);
271 }
272
273 /*
274 * Delete TLB entry in MMU for a given page (??? address)
275 * NOTE One TLB entry contains translation for single PAGE
276 */
277
278 void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
279 {
280 const unsigned int cpu = smp_processor_id();
281 unsigned long flags;
282
283 /* Note that it is critical that interrupts are DISABLED between
284 * checking the ASID and using it flush the TLB entry
285 */
286 local_irq_save(flags);
287
288 if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
289 tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm, cpu));
290 }
291
292 local_irq_restore(flags);
293 }
294
295 #ifdef CONFIG_SMP
296
297 struct tlb_args {
298 struct vm_area_struct *ta_vma;
299 unsigned long ta_start;
300 unsigned long ta_end;
301 };
302
303 static inline void ipi_flush_tlb_page(void *arg)
304 {
305 struct tlb_args *ta = arg;
306
307 local_flush_tlb_page(ta->ta_vma, ta->ta_start);
308 }
309
310 static inline void ipi_flush_tlb_range(void *arg)
311 {
312 struct tlb_args *ta = arg;
313
314 local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
315 }
316
317 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
318 static inline void ipi_flush_pmd_tlb_range(void *arg)
319 {
320 struct tlb_args *ta = arg;
321
322 local_flush_pmd_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
323 }
324 #endif
325
326 static inline void ipi_flush_tlb_kernel_range(void *arg)
327 {
328 struct tlb_args *ta = (struct tlb_args *)arg;
329
330 local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
331 }
332
333 void flush_tlb_all(void)
334 {
335 on_each_cpu((smp_call_func_t)local_flush_tlb_all, NULL, 1);
336 }
337
338 void flush_tlb_mm(struct mm_struct *mm)
339 {
340 on_each_cpu_mask(mm_cpumask(mm), (smp_call_func_t)local_flush_tlb_mm,
341 mm, 1);
342 }
343
344 void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
345 {
346 struct tlb_args ta = {
347 .ta_vma = vma,
348 .ta_start = uaddr
349 };
350
351 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page, &ta, 1);
352 }
353
354 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
355 unsigned long end)
356 {
357 struct tlb_args ta = {
358 .ta_vma = vma,
359 .ta_start = start,
360 .ta_end = end
361 };
362
363 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_range, &ta, 1);
364 }
365
366 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
367 void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
368 unsigned long end)
369 {
370 struct tlb_args ta = {
371 .ta_vma = vma,
372 .ta_start = start,
373 .ta_end = end
374 };
375
376 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_pmd_tlb_range, &ta, 1);
377 }
378 #endif
379
380 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
381 {
382 struct tlb_args ta = {
383 .ta_start = start,
384 .ta_end = end
385 };
386
387 on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1);
388 }
389 #endif
390
391 /*
392 * Routine to create a TLB entry
393 */
394 static void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
395 {
396 unsigned long flags;
397 unsigned int asid_or_sasid, rwx;
398 unsigned long pd0;
399 phys_addr_t pd1;
400
401 /*
402 * create_tlb() assumes that current->mm == vma->mm, since
403 * -it ASID for TLB entry is fetched from MMU ASID reg (valid for curr)
404 * -completes the lazy write to SASID reg (again valid for curr tsk)
405 *
406 * Removing the assumption involves
407 * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.
408 * -More importantly it makes this handler inconsistent with fast-path
409 * TLB Refill handler which always deals with "current"
410 *
411 * Let's see the use cases when current->mm != vma->mm and we land here
412 * 1. execve->copy_strings()->__get_user_pages->handle_mm_fault
413 * Here VM wants to pre-install a TLB entry for user stack while
414 * current->mm still points to pre-execve mm (hence the condition).
415 * However the stack vaddr is soon relocated (randomization) and
416 * move_page_tables() tries to undo that TLB entry.
417 * Thus not creating TLB entry is not any worse.
418 *
419 * 2. ptrace(POKETEXT) causes a CoW - debugger(current) inserting a
420 * breakpoint in debugged task. Not creating a TLB now is not
421 * performance critical.
422 *
423 * Both the cases above are not good enough for code churn.
424 */
425 if (current->active_mm != vma->vm_mm)
426 return;
427
428 local_irq_save(flags);
429
430 vaddr &= PAGE_MASK;
431
432 /* update this PTE credentials */
433 pte_val(*ptep) |= (_PAGE_PRESENT | _PAGE_ACCESSED);
434
435 /* Create HW TLB(PD0,PD1) from PTE */
436
437 /* ASID for this task */
438 asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff;
439
440 pd0 = vaddr | asid_or_sasid | (pte_val(*ptep) & PTE_BITS_IN_PD0);
441
442 /*
443 * ARC MMU provides fully orthogonal access bits for K/U mode,
444 * however Linux only saves 1 set to save PTE real-estate
445 * Here we convert 3 PTE bits into 6 MMU bits:
446 * -Kernel only entries have Kr Kw Kx 0 0 0
447 * -User entries have mirrored K and U bits
448 */
449 rwx = pte_val(*ptep) & PTE_BITS_RWX;
450
451 if (pte_val(*ptep) & _PAGE_GLOBAL)
452 rwx <<= 3; /* r w x => Kr Kw Kx 0 0 0 */
453 else
454 rwx |= (rwx << 3); /* r w x => Kr Kw Kx Ur Uw Ux */
455
456 pd1 = rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1);
457
458 tlb_entry_insert(pd0, pd1);
459
460 local_irq_restore(flags);
461 }
462
463 /*
464 * Called at the end of pagefault, for a userspace mapped page
465 * -pre-install the corresponding TLB entry into MMU
466 * -Finalize the delayed D-cache flush of kernel mapping of page due to
467 * flush_dcache_page(), copy_user_page()
468 *
469 * Note that flush (when done) involves both WBACK - so physical page is
470 * in sync as well as INV - so any non-congruent aliases don't remain
471 */
472 void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma,
473 unsigned long vaddr_unaligned, pte_t *ptep, unsigned int nr)
474 {
475 unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
476 phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK_PHYS;
477 struct page *page = pfn_to_page(pte_pfn(*ptep));
478
479 create_tlb(vma, vaddr, ptep);
480
481 if (page == ZERO_PAGE(0))
482 return;
483
484 /*
485 * For executable pages, since icache doesn't snoop dcache, any
486 * dirty K-mapping of a code page needs to be wback+inv so that
487 * icache fetch by userspace sees code correctly.
488 */
489 if (vma->vm_flags & VM_EXEC) {
490 struct folio *folio = page_folio(page);
491 int dirty = !test_and_set_bit(PG_dc_clean, &folio->flags);
492 if (dirty) {
493 unsigned long offset = offset_in_folio(folio, paddr);
494 nr = folio_nr_pages(folio);
495 paddr -= offset;
496 vaddr -= offset;
497 /* wback + inv dcache lines (K-mapping) */
498 __flush_dcache_pages(paddr, paddr, nr);
499
500 /* invalidate any existing icache lines (U-mapping) */
501 if (vma->vm_flags & VM_EXEC)
502 __inv_icache_pages(paddr, vaddr, nr);
503 }
504 }
505 }
506
507 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
508
509 /*
510 * MMUv4 in HS38x cores supports Super Pages which are basis for Linux THP
511 * support.
512 *
513 * Normal and Super pages can co-exist (ofcourse not overlap) in TLB with a
514 * new bit "SZ" in TLB page descriptor to distinguish between them.
515 * Super Page size is configurable in hardware (4K to 16M), but fixed once
516 * RTL builds.
517 *
518 * The exact THP size a Linux configuration will support is a function of:
519 * - MMU page size (typical 8K, RTL fixed)
520 * - software page walker address split between PGD:PTE:PFN (typical
521 * 11:8:13, but can be changed with 1 line)
522 * So for above default, THP size supported is 8K * (2^8) = 2M
523 *
524 * Default Page Walker is 2 levels, PGD:PTE:PFN, which in THP regime
525 * reduces to 1 level (as PTE is folded into PGD and canonically referred
526 * to as PMD).
527 * Thus THP PMD accessors are implemented in terms of PTE (just like sparc)
528 */
529
530 void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
531 pmd_t *pmd)
532 {
533 pte_t pte = __pte(pmd_val(*pmd));
534 update_mmu_cache_range(NULL, vma, addr, &pte, HPAGE_PMD_NR);
535 }
536
537 void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
538 unsigned long end)
539 {
540 unsigned int cpu;
541 unsigned long flags;
542
543 local_irq_save(flags);
544
545 cpu = smp_processor_id();
546
547 if (likely(asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID)) {
548 unsigned int asid = hw_pid(vma->vm_mm, cpu);
549
550 /* No need to loop here: this will always be for 1 Huge Page */
551 tlb_entry_erase(start | _PAGE_HW_SZ | asid);
552 }
553
554 local_irq_restore(flags);
555 }
556
557 #endif
558
559 /* Read the Cache Build Configuration Registers, Decode them and save into
560 * the cpuinfo structure for later use.
561 * No Validation is done here, simply read/convert the BCRs
562 */
563 int arc_mmu_mumbojumbo(int c, char *buf, int len)
564 {
565 struct cpuinfo_arc_mmu *mmu = &mmuinfo;
566 unsigned int bcr, u_dtlb, u_itlb, sasid;
567 struct bcr_mmu_3 *mmu3;
568 struct bcr_mmu_4 *mmu4;
569 char super_pg[64] = "";
570 int n = 0;
571
572 bcr = read_aux_reg(ARC_REG_MMU_BCR);
573 mmu->ver = (bcr >> 24);
574
575 if (is_isa_arcompact() && mmu->ver == 3) {
576 mmu3 = (struct bcr_mmu_3 *)&bcr;
577 mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
578 mmu->sets = 1 << mmu3->sets;
579 mmu->ways = 1 << mmu3->ways;
580 u_dtlb = mmu3->u_dtlb;
581 u_itlb = mmu3->u_itlb;
582 sasid = mmu3->sasid;
583 } else {
584 mmu4 = (struct bcr_mmu_4 *)&bcr;
585 mmu->pg_sz_k = 1 << (mmu4->sz0 - 1);
586 mmu->s_pg_sz_m = 1 << (mmu4->sz1 - 11);
587 mmu->sets = 64 << mmu4->n_entry;
588 mmu->ways = mmu4->n_ways * 2;
589 u_dtlb = mmu4->u_dtlb * 4;
590 u_itlb = mmu4->u_itlb * 4;
591 sasid = mmu4->sasid;
592 mmu->pae = mmu4->pae;
593 }
594
595 if (mmu->s_pg_sz_m)
596 scnprintf(super_pg, 64, "/%dM%s",
597 mmu->s_pg_sz_m,
598 IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) ? " (THP enabled)":"");
599
600 n += scnprintf(buf + n, len - n,
601 "MMU [v%x]\t: %dk%s, swalk %d lvl, JTLB %dx%d, uDTLB %d, uITLB %d%s%s%s\n",
602 mmu->ver, mmu->pg_sz_k, super_pg, CONFIG_PGTABLE_LEVELS,
603 mmu->sets, mmu->ways,
604 u_dtlb, u_itlb,
605 IS_AVAIL1(sasid, ", SASID"),
606 IS_AVAIL2(mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40));
607
608 return n;
609 }
610
611 int pae40_exist_but_not_enab(void)
612 {
613 return mmuinfo.pae && !is_pae40_enabled();
614 }
615
616 void arc_mmu_init(void)
617 {
618 struct cpuinfo_arc_mmu *mmu = &mmuinfo;
619 int compat = 0;
620
621 /*
622 * Can't be done in processor.h due to header include dependencies
623 */
624 BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE));
625
626 /*
627 * stack top size sanity check,
628 * Can't be done in processor.h due to header include dependencies
629 */
630 BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE));
631
632 /*
633 * Ensure that MMU features assumed by kernel exist in hardware.
634 * - For older ARC700 cpus, only v3 supported
635 * - For HS cpus, v4 was baseline and v5 is backwards compatible
636 * (will run older software).
637 */
638 if (is_isa_arcompact() && mmu->ver == 3)
639 compat = 1;
640 else if (is_isa_arcv2() && mmu->ver >= 4)
641 compat = 1;
642
643 if (!compat)
644 panic("MMU ver %d doesn't match kernel built for\n", mmu->ver);
645
646 if (mmu->pg_sz_k != TO_KB(PAGE_SIZE))
647 panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
648
649 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
650 mmu->s_pg_sz_m != TO_MB(HPAGE_PMD_SIZE))
651 panic("MMU Super pg size != Linux HPAGE_PMD_SIZE (%luM)\n",
652 (unsigned long)TO_MB(HPAGE_PMD_SIZE));
653
654 if (IS_ENABLED(CONFIG_ARC_HAS_PAE40) && !mmu->pae)
655 panic("Hardware doesn't support PAE40\n");
656
657 /* Enable the MMU with ASID 0 */
658 mmu_setup_asid(NULL, 0);
659
660 /* cache the pgd pointer in MMU SCRATCH reg (ARCv2 only) */
661 mmu_setup_pgd(NULL, swapper_pg_dir);
662
663 if (pae40_exist_but_not_enab())
664 write_aux_reg(ARC_REG_TLBPD1HI, 0);
665 }
666
667 /*
668 * TLB Programmer's Model uses Linear Indexes: 0 to {255, 511} for 128 x {2,4}
669 * The mapping is Column-first.
670 * --------------------- -----------
671 * |way0|way1|way2|way3| |way0|way1|
672 * --------------------- -----------
673 * [set0] | 0 | 1 | 2 | 3 | | 0 | 1 |
674 * [set1] | 4 | 5 | 6 | 7 | | 2 | 3 |
675 * ~ ~ ~ ~
676 * [set127] | 508| 509| 510| 511| | 254| 255|
677 * --------------------- -----------
678 * For normal operations we don't(must not) care how above works since
679 * MMU cmd getIndex(vaddr) abstracts that out.
680 * However for walking WAYS of a SET, we need to know this
681 */
682 #define SET_WAY_TO_IDX(mmu, set, way) ((set) * mmu->ways + (way))
683
684 /* Handling of Duplicate PD (TLB entry) in MMU.
685 * -Could be due to buggy customer tapeouts or obscure kernel bugs
686 * -MMU complaints not at the time of duplicate PD installation, but at the
687 * time of lookup matching multiple ways.
688 * -Ideally these should never happen - but if they do - workaround by deleting
689 * the duplicate one.
690 * -Knob to be verbose abt it.(TODO: hook them up to debugfs)
691 */
692 volatile int dup_pd_silent; /* Be silent abt it or complain (default) */
693
694 void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
695 struct pt_regs *regs)
696 {
697 struct cpuinfo_arc_mmu *mmu = &mmuinfo;
698 unsigned long flags;
699 int set, n_ways = mmu->ways;
700
701 n_ways = min(n_ways, 4);
702 BUG_ON(mmu->ways > 4);
703
704 local_irq_save(flags);
705
706 /* loop thru all sets of TLB */
707 for (set = 0; set < mmu->sets; set++) {
708
709 int is_valid, way;
710 unsigned int pd0[4];
711
712 /* read out all the ways of current set */
713 for (way = 0, is_valid = 0; way < n_ways; way++) {
714 write_aux_reg(ARC_REG_TLBINDEX,
715 SET_WAY_TO_IDX(mmu, set, way));
716 write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
717 pd0[way] = read_aux_reg(ARC_REG_TLBPD0);
718 is_valid |= pd0[way] & _PAGE_PRESENT;
719 pd0[way] &= PAGE_MASK;
720 }
721
722 /* If all the WAYS in SET are empty, skip to next SET */
723 if (!is_valid)
724 continue;
725
726 /* Scan the set for duplicate ways: needs a nested loop */
727 for (way = 0; way < n_ways - 1; way++) {
728
729 int n;
730
731 if (!pd0[way])
732 continue;
733
734 for (n = way + 1; n < n_ways; n++) {
735 if (pd0[way] != pd0[n])
736 continue;
737
738 if (!dup_pd_silent)
739 pr_info("Dup TLB PD0 %08x @ set %d ways %d,%d\n",
740 pd0[way], set, way, n);
741
742 /*
743 * clear entry @way and not @n.
744 * This is critical to our optimised loop
745 */
746 pd0[way] = 0;
747 write_aux_reg(ARC_REG_TLBINDEX,
748 SET_WAY_TO_IDX(mmu, set, way));
749 __tlb_entry_erase();
750 }
751 }
752 }
753
754 local_irq_restore(flags);
755 }
756
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.