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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * TLB Management (flush/create/diagnostics) for ARC700
4 *
5 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
6 *
7 * vineetg: Aug 2011
8 * -Reintroduce duplicate PD fixup - some customer chips still have the issue
9 *
10 * vineetg: May 2011
11 * -No need to flush_cache_page( ) for each call to update_mmu_cache()
12 * some of the LMBench tests improved amazingly
13 * = page-fault thrice as fast (75 usec to 28 usec)
14 * = mmap twice as fast (9.6 msec to 4.6 msec),
15 * = fork (5.3 msec to 3.7 msec)
16 *
17 * vineetg: April 2011 :
18 * -MMU v3: PD{0,1} bits layout changed: They don't overlap anymore,
19 * helps avoid a shift when preparing PD0 from PTE
20 *
21 * vineetg: April 2011 : Preparing for MMU V3
22 * -MMU v2/v3 BCRs decoded differently
23 * -Remove TLB_SIZE hardcoding as it's variable now: 256 or 512
24 * -tlb_entry_erase( ) can be void
25 * -local_flush_tlb_range( ):
26 * = need not "ceil" @end
27 * = walks MMU only if range spans < 32 entries, as opposed to 256
28 *
29 * Vineetg: Sept 10th 2008
30 * -Changes related to MMU v2 (Rel 4.8)
31 *
32 * Vineetg: Aug 29th 2008
33 * -In TLB Flush operations (Metal Fix MMU) there is a explict command to
34 * flush Micro-TLBS. If TLB Index Reg is invalid prior to TLBIVUTLB cmd,
35 * it fails. Thus need to load it with ANY valid value before invoking
36 * TLBIVUTLB cmd
37 *
38 * Vineetg: Aug 21th 2008:
39 * -Reduced the duration of IRQ lockouts in TLB Flush routines
40 * -Multiple copies of TLB erase code seperated into a "single" function
41 * -In TLB Flush routines, interrupt disabling moved UP to retrieve ASID
42 * in interrupt-safe region.
43 *
44 * Vineetg: April 23rd Bug #93131
45 * Problem: tlb_flush_kernel_range() doesn't do anything if the range to
46 * flush is more than the size of TLB itself.
47 *
48 * Rahul Trivedi : Codito Technologies 2004
49 */
50
51#include <linux/module.h>
52#include <linux/bug.h>
53#include <linux/mm_types.h>
54
55#include <asm/arcregs.h>
56#include <asm/setup.h>
57#include <asm/mmu_context.h>
58#include <asm/mmu.h>
59
60/* Need for ARC MMU v2
61 *
62 * ARC700 MMU-v1 had a Joint-TLB for Code and Data and is 2 way set-assoc.
63 * For a memcpy operation with 3 players (src/dst/code) such that all 3 pages
64 * map into same set, there would be contention for the 2 ways causing severe
65 * Thrashing.
66 *
67 * Although J-TLB is 2 way set assoc, ARC700 caches J-TLB into uTLBS which has
68 * much higher associativity. u-D-TLB is 8 ways, u-I-TLB is 4 ways.
69 * Given this, the thrasing problem should never happen because once the 3
70 * J-TLB entries are created (even though 3rd will knock out one of the prev
71 * two), the u-D-TLB and u-I-TLB will have what is required to accomplish memcpy
72 *
73 * Yet we still see the Thrashing because a J-TLB Write cause flush of u-TLBs.
74 * This is a simple design for keeping them in sync. So what do we do?
75 * The solution which James came up was pretty neat. It utilised the assoc
76 * of uTLBs by not invalidating always but only when absolutely necessary.
77 *
78 * - Existing TLB commands work as before
79 * - New command (TLBWriteNI) for TLB write without clearing uTLBs
80 * - New command (TLBIVUTLB) to invalidate uTLBs.
81 *
82 * The uTLBs need only be invalidated when pages are being removed from the
83 * OS page table. If a 'victim' TLB entry is being overwritten in the main TLB
84 * as a result of a miss, the removed entry is still allowed to exist in the
85 * uTLBs as it is still valid and present in the OS page table. This allows the
86 * full associativity of the uTLBs to hide the limited associativity of the main
87 * TLB.
88 *
89 * During a miss handler, the new "TLBWriteNI" command is used to load
90 * entries without clearing the uTLBs.
91 *
92 * When the OS page table is updated, TLB entries that may be associated with a
93 * removed page are removed (flushed) from the TLB using TLBWrite. In this
94 * circumstance, the uTLBs must also be cleared. This is done by using the
95 * existing TLBWrite command. An explicit IVUTLB is also required for those
96 * corner cases when TLBWrite was not executed at all because the corresp
97 * J-TLB entry got evicted/replaced.
98 */
99
100
101/* A copy of the ASID from the PID reg is kept in asid_cache */
102DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;
103
104static int __read_mostly pae_exists;
105
106/*
107 * Utility Routine to erase a J-TLB entry
108 * Caller needs to setup Index Reg (manually or via getIndex)
109 */
110static inline void __tlb_entry_erase(void)
111{
112 write_aux_reg(ARC_REG_TLBPD1, 0);
113
114 if (is_pae40_enabled())
115 write_aux_reg(ARC_REG_TLBPD1HI, 0);
116
117 write_aux_reg(ARC_REG_TLBPD0, 0);
118 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
119}
120
121#if (CONFIG_ARC_MMU_VER < 4)
122
123static inline unsigned int tlb_entry_lkup(unsigned long vaddr_n_asid)
124{
125 unsigned int idx;
126
127 write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid);
128
129 write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);
130 idx = read_aux_reg(ARC_REG_TLBINDEX);
131
132 return idx;
133}
134
135static void tlb_entry_erase(unsigned int vaddr_n_asid)
136{
137 unsigned int idx;
138
139 /* Locate the TLB entry for this vaddr + ASID */
140 idx = tlb_entry_lkup(vaddr_n_asid);
141
142 /* No error means entry found, zero it out */
143 if (likely(!(idx & TLB_LKUP_ERR))) {
144 __tlb_entry_erase();
145 } else {
146 /* Duplicate entry error */
147 WARN(idx == TLB_DUP_ERR, "Probe returned Dup PD for %x\n",
148 vaddr_n_asid);
149 }
150}
151
152/****************************************************************************
153 * ARC700 MMU caches recently used J-TLB entries (RAM) as uTLBs (FLOPs)
154 *
155 * New IVUTLB cmd in MMU v2 explictly invalidates the uTLB
156 *
157 * utlb_invalidate ( )
158 * -For v2 MMU calls Flush uTLB Cmd
159 * -For v1 MMU does nothing (except for Metal Fix v1 MMU)
160 * This is because in v1 TLBWrite itself invalidate uTLBs
161 ***************************************************************************/
162
163static void utlb_invalidate(void)
164{
165#if (CONFIG_ARC_MMU_VER >= 2)
166
167#if (CONFIG_ARC_MMU_VER == 2)
168 /* MMU v2 introduced the uTLB Flush command.
169 * There was however an obscure hardware bug, where uTLB flush would
170 * fail when a prior probe for J-TLB (both totally unrelated) would
171 * return lkup err - because the entry didn't exist in MMU.
172 * The Workround was to set Index reg with some valid value, prior to
173 * flush. This was fixed in MMU v3 hence not needed any more
174 */
175 unsigned int idx;
176
177 /* make sure INDEX Reg is valid */
178 idx = read_aux_reg(ARC_REG_TLBINDEX);
179
180 /* If not write some dummy val */
181 if (unlikely(idx & TLB_LKUP_ERR))
182 write_aux_reg(ARC_REG_TLBINDEX, 0xa);
183#endif
184
185 write_aux_reg(ARC_REG_TLBCOMMAND, TLBIVUTLB);
186#endif
187
188}
189
190static void tlb_entry_insert(unsigned int pd0, pte_t pd1)
191{
192 unsigned int idx;
193
194 /*
195 * First verify if entry for this vaddr+ASID already exists
196 * This also sets up PD0 (vaddr, ASID..) for final commit
197 */
198 idx = tlb_entry_lkup(pd0);
199
200 /*
201 * If Not already present get a free slot from MMU.
202 * Otherwise, Probe would have located the entry and set INDEX Reg
203 * with existing location. This will cause Write CMD to over-write
204 * existing entry with new PD0 and PD1
205 */
206 if (likely(idx & TLB_LKUP_ERR))
207 write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);
208
209 /* setup the other half of TLB entry (pfn, rwx..) */
210 write_aux_reg(ARC_REG_TLBPD1, pd1);
211
212 /*
213 * Commit the Entry to MMU
214 * It doesn't sound safe to use the TLBWriteNI cmd here
215 * which doesn't flush uTLBs. I'd rather be safe than sorry.
216 */
217 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
218}
219
220#else /* CONFIG_ARC_MMU_VER >= 4) */
221
222static void utlb_invalidate(void)
223{
224 /* No need since uTLB is always in sync with JTLB */
225}
226
227static void tlb_entry_erase(unsigned int vaddr_n_asid)
228{
229 write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid | _PAGE_PRESENT);
230 write_aux_reg(ARC_REG_TLBCOMMAND, TLBDeleteEntry);
231}
232
233static void tlb_entry_insert(unsigned int pd0, pte_t pd1)
234{
235 write_aux_reg(ARC_REG_TLBPD0, pd0);
236 write_aux_reg(ARC_REG_TLBPD1, pd1);
237
238 if (is_pae40_enabled())
239 write_aux_reg(ARC_REG_TLBPD1HI, (u64)pd1 >> 32);
240
241 write_aux_reg(ARC_REG_TLBCOMMAND, TLBInsertEntry);
242}
243
244#endif
245
246/*
247 * Un-conditionally (without lookup) erase the entire MMU contents
248 */
249
250noinline void local_flush_tlb_all(void)
251{
252 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
253 unsigned long flags;
254 unsigned int entry;
255 int num_tlb = mmu->sets * mmu->ways;
256
257 local_irq_save(flags);
258
259 /* Load PD0 and PD1 with template for a Blank Entry */
260 write_aux_reg(ARC_REG_TLBPD1, 0);
261
262 if (is_pae40_enabled())
263 write_aux_reg(ARC_REG_TLBPD1HI, 0);
264
265 write_aux_reg(ARC_REG_TLBPD0, 0);
266
267 for (entry = 0; entry < num_tlb; entry++) {
268 /* write this entry to the TLB */
269 write_aux_reg(ARC_REG_TLBINDEX, entry);
270 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
271 }
272
273 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
274 const int stlb_idx = 0x800;
275
276 /* Blank sTLB entry */
277 write_aux_reg(ARC_REG_TLBPD0, _PAGE_HW_SZ);
278
279 for (entry = stlb_idx; entry < stlb_idx + 16; entry++) {
280 write_aux_reg(ARC_REG_TLBINDEX, entry);
281 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
282 }
283 }
284
285 utlb_invalidate();
286
287 local_irq_restore(flags);
288}
289
290/*
291 * Flush the entrie MM for userland. The fastest way is to move to Next ASID
292 */
293noinline void local_flush_tlb_mm(struct mm_struct *mm)
294{
295 /*
296 * Small optimisation courtesy IA64
297 * flush_mm called during fork,exit,munmap etc, multiple times as well.
298 * Only for fork( ) do we need to move parent to a new MMU ctxt,
299 * all other cases are NOPs, hence this check.
300 */
301 if (atomic_read(&mm->mm_users) == 0)
302 return;
303
304 /*
305 * - Move to a new ASID, but only if the mm is still wired in
306 * (Android Binder ended up calling this for vma->mm != tsk->mm,
307 * causing h/w - s/w ASID to get out of sync)
308 * - Also get_new_mmu_context() new implementation allocates a new
309 * ASID only if it is not allocated already - so unallocate first
310 */
311 destroy_context(mm);
312 if (current->mm == mm)
313 get_new_mmu_context(mm);
314}
315
316/*
317 * Flush a Range of TLB entries for userland.
318 * @start is inclusive, while @end is exclusive
319 * Difference between this and Kernel Range Flush is
320 * -Here the fastest way (if range is too large) is to move to next ASID
321 * without doing any explicit Shootdown
322 * -In case of kernel Flush, entry has to be shot down explictly
323 */
324void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
325 unsigned long end)
326{
327 const unsigned int cpu = smp_processor_id();
328 unsigned long flags;
329
330 /* If range @start to @end is more than 32 TLB entries deep,
331 * its better to move to a new ASID rather than searching for
332 * individual entries and then shooting them down
333 *
334 * The calc above is rough, doesn't account for unaligned parts,
335 * since this is heuristics based anyways
336 */
337 if (unlikely((end - start) >= PAGE_SIZE * 32)) {
338 local_flush_tlb_mm(vma->vm_mm);
339 return;
340 }
341
342 /*
343 * @start moved to page start: this alone suffices for checking
344 * loop end condition below, w/o need for aligning @end to end
345 * e.g. 2000 to 4001 will anyhow loop twice
346 */
347 start &= PAGE_MASK;
348
349 local_irq_save(flags);
350
351 if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
352 while (start < end) {
353 tlb_entry_erase(start | hw_pid(vma->vm_mm, cpu));
354 start += PAGE_SIZE;
355 }
356 }
357
358 utlb_invalidate();
359
360 local_irq_restore(flags);
361}
362
363/* Flush the kernel TLB entries - vmalloc/modules (Global from MMU perspective)
364 * @start, @end interpreted as kvaddr
365 * Interestingly, shared TLB entries can also be flushed using just
366 * @start,@end alone (interpreted as user vaddr), although technically SASID
367 * is also needed. However our smart TLbProbe lookup takes care of that.
368 */
369void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
370{
371 unsigned long flags;
372
373 /* exactly same as above, except for TLB entry not taking ASID */
374
375 if (unlikely((end - start) >= PAGE_SIZE * 32)) {
376 local_flush_tlb_all();
377 return;
378 }
379
380 start &= PAGE_MASK;
381
382 local_irq_save(flags);
383 while (start < end) {
384 tlb_entry_erase(start);
385 start += PAGE_SIZE;
386 }
387
388 utlb_invalidate();
389
390 local_irq_restore(flags);
391}
392
393/*
394 * Delete TLB entry in MMU for a given page (??? address)
395 * NOTE One TLB entry contains translation for single PAGE
396 */
397
398void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
399{
400 const unsigned int cpu = smp_processor_id();
401 unsigned long flags;
402
403 /* Note that it is critical that interrupts are DISABLED between
404 * checking the ASID and using it flush the TLB entry
405 */
406 local_irq_save(flags);
407
408 if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
409 tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm, cpu));
410 utlb_invalidate();
411 }
412
413 local_irq_restore(flags);
414}
415
416#ifdef CONFIG_SMP
417
418struct tlb_args {
419 struct vm_area_struct *ta_vma;
420 unsigned long ta_start;
421 unsigned long ta_end;
422};
423
424static inline void ipi_flush_tlb_page(void *arg)
425{
426 struct tlb_args *ta = arg;
427
428 local_flush_tlb_page(ta->ta_vma, ta->ta_start);
429}
430
431static inline void ipi_flush_tlb_range(void *arg)
432{
433 struct tlb_args *ta = arg;
434
435 local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
436}
437
438#ifdef CONFIG_TRANSPARENT_HUGEPAGE
439static inline void ipi_flush_pmd_tlb_range(void *arg)
440{
441 struct tlb_args *ta = arg;
442
443 local_flush_pmd_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
444}
445#endif
446
447static inline void ipi_flush_tlb_kernel_range(void *arg)
448{
449 struct tlb_args *ta = (struct tlb_args *)arg;
450
451 local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
452}
453
454void flush_tlb_all(void)
455{
456 on_each_cpu((smp_call_func_t)local_flush_tlb_all, NULL, 1);
457}
458
459void flush_tlb_mm(struct mm_struct *mm)
460{
461 on_each_cpu_mask(mm_cpumask(mm), (smp_call_func_t)local_flush_tlb_mm,
462 mm, 1);
463}
464
465void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
466{
467 struct tlb_args ta = {
468 .ta_vma = vma,
469 .ta_start = uaddr
470 };
471
472 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page, &ta, 1);
473}
474
475void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
476 unsigned long end)
477{
478 struct tlb_args ta = {
479 .ta_vma = vma,
480 .ta_start = start,
481 .ta_end = end
482 };
483
484 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_range, &ta, 1);
485}
486
487#ifdef CONFIG_TRANSPARENT_HUGEPAGE
488void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
489 unsigned long end)
490{
491 struct tlb_args ta = {
492 .ta_vma = vma,
493 .ta_start = start,
494 .ta_end = end
495 };
496
497 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_pmd_tlb_range, &ta, 1);
498}
499#endif
500
501void flush_tlb_kernel_range(unsigned long start, unsigned long end)
502{
503 struct tlb_args ta = {
504 .ta_start = start,
505 .ta_end = end
506 };
507
508 on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1);
509}
510#endif
511
512/*
513 * Routine to create a TLB entry
514 */
515void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
516{
517 unsigned long flags;
518 unsigned int asid_or_sasid, rwx;
519 unsigned long pd0;
520 pte_t pd1;
521
522 /*
523 * create_tlb() assumes that current->mm == vma->mm, since
524 * -it ASID for TLB entry is fetched from MMU ASID reg (valid for curr)
525 * -completes the lazy write to SASID reg (again valid for curr tsk)
526 *
527 * Removing the assumption involves
528 * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.
529 * -Fix the TLB paranoid debug code to not trigger false negatives.
530 * -More importantly it makes this handler inconsistent with fast-path
531 * TLB Refill handler which always deals with "current"
532 *
533 * Lets see the use cases when current->mm != vma->mm and we land here
534 * 1. execve->copy_strings()->__get_user_pages->handle_mm_fault
535 * Here VM wants to pre-install a TLB entry for user stack while
536 * current->mm still points to pre-execve mm (hence the condition).
537 * However the stack vaddr is soon relocated (randomization) and
538 * move_page_tables() tries to undo that TLB entry.
539 * Thus not creating TLB entry is not any worse.
540 *
541 * 2. ptrace(POKETEXT) causes a CoW - debugger(current) inserting a
542 * breakpoint in debugged task. Not creating a TLB now is not
543 * performance critical.
544 *
545 * Both the cases above are not good enough for code churn.
546 */
547 if (current->active_mm != vma->vm_mm)
548 return;
549
550 local_irq_save(flags);
551
552 tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), vaddr);
553
554 vaddr &= PAGE_MASK;
555
556 /* update this PTE credentials */
557 pte_val(*ptep) |= (_PAGE_PRESENT | _PAGE_ACCESSED);
558
559 /* Create HW TLB(PD0,PD1) from PTE */
560
561 /* ASID for this task */
562 asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff;
563
564 pd0 = vaddr | asid_or_sasid | (pte_val(*ptep) & PTE_BITS_IN_PD0);
565
566 /*
567 * ARC MMU provides fully orthogonal access bits for K/U mode,
568 * however Linux only saves 1 set to save PTE real-estate
569 * Here we convert 3 PTE bits into 6 MMU bits:
570 * -Kernel only entries have Kr Kw Kx 0 0 0
571 * -User entries have mirrored K and U bits
572 */
573 rwx = pte_val(*ptep) & PTE_BITS_RWX;
574
575 if (pte_val(*ptep) & _PAGE_GLOBAL)
576 rwx <<= 3; /* r w x => Kr Kw Kx 0 0 0 */
577 else
578 rwx |= (rwx << 3); /* r w x => Kr Kw Kx Ur Uw Ux */
579
580 pd1 = rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1);
581
582 tlb_entry_insert(pd0, pd1);
583
584 local_irq_restore(flags);
585}
586
587/*
588 * Called at the end of pagefault, for a userspace mapped page
589 * -pre-install the corresponding TLB entry into MMU
590 * -Finalize the delayed D-cache flush of kernel mapping of page due to
591 * flush_dcache_page(), copy_user_page()
592 *
593 * Note that flush (when done) involves both WBACK - so physical page is
594 * in sync as well as INV - so any non-congruent aliases don't remain
595 */
596void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
597 pte_t *ptep)
598{
599 unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
600 phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK;
601 struct page *page = pfn_to_page(pte_pfn(*ptep));
602
603 create_tlb(vma, vaddr, ptep);
604
605 if (page == ZERO_PAGE(0)) {
606 return;
607 }
608
609 /*
610 * Exec page : Independent of aliasing/page-color considerations,
611 * since icache doesn't snoop dcache on ARC, any dirty
612 * K-mapping of a code page needs to be wback+inv so that
613 * icache fetch by userspace sees code correctly.
614 * !EXEC page: If K-mapping is NOT congruent to U-mapping, flush it
615 * so userspace sees the right data.
616 * (Avoids the flush for Non-exec + congruent mapping case)
617 */
618 if ((vma->vm_flags & VM_EXEC) ||
619 addr_not_cache_congruent(paddr, vaddr)) {
620
621 int dirty = !test_and_set_bit(PG_dc_clean, &page->flags);
622 if (dirty) {
623 /* wback + inv dcache lines (K-mapping) */
624 __flush_dcache_page(paddr, paddr);
625
626 /* invalidate any existing icache lines (U-mapping) */
627 if (vma->vm_flags & VM_EXEC)
628 __inv_icache_page(paddr, vaddr);
629 }
630 }
631}
632
633#ifdef CONFIG_TRANSPARENT_HUGEPAGE
634
635/*
636 * MMUv4 in HS38x cores supports Super Pages which are basis for Linux THP
637 * support.
638 *
639 * Normal and Super pages can co-exist (ofcourse not overlap) in TLB with a
640 * new bit "SZ" in TLB page descriptor to distinguish between them.
641 * Super Page size is configurable in hardware (4K to 16M), but fixed once
642 * RTL builds.
643 *
644 * The exact THP size a Linx configuration will support is a function of:
645 * - MMU page size (typical 8K, RTL fixed)
646 * - software page walker address split between PGD:PTE:PFN (typical
647 * 11:8:13, but can be changed with 1 line)
648 * So for above default, THP size supported is 8K * (2^8) = 2M
649 *
650 * Default Page Walker is 2 levels, PGD:PTE:PFN, which in THP regime
651 * reduces to 1 level (as PTE is folded into PGD and canonically referred
652 * to as PMD).
653 * Thus THP PMD accessors are implemented in terms of PTE (just like sparc)
654 */
655
656void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
657 pmd_t *pmd)
658{
659 pte_t pte = __pte(pmd_val(*pmd));
660 update_mmu_cache(vma, addr, &pte);
661}
662
663void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
664 pgtable_t pgtable)
665{
666 struct list_head *lh = (struct list_head *) pgtable;
667
668 assert_spin_locked(&mm->page_table_lock);
669
670 /* FIFO */
671 if (!pmd_huge_pte(mm, pmdp))
672 INIT_LIST_HEAD(lh);
673 else
674 list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
675 pmd_huge_pte(mm, pmdp) = pgtable;
676}
677
678pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
679{
680 struct list_head *lh;
681 pgtable_t pgtable;
682
683 assert_spin_locked(&mm->page_table_lock);
684
685 pgtable = pmd_huge_pte(mm, pmdp);
686 lh = (struct list_head *) pgtable;
687 if (list_empty(lh))
688 pmd_huge_pte(mm, pmdp) = NULL;
689 else {
690 pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
691 list_del(lh);
692 }
693
694 pte_val(pgtable[0]) = 0;
695 pte_val(pgtable[1]) = 0;
696
697 return pgtable;
698}
699
700void local_flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
701 unsigned long end)
702{
703 unsigned int cpu;
704 unsigned long flags;
705
706 local_irq_save(flags);
707
708 cpu = smp_processor_id();
709
710 if (likely(asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID)) {
711 unsigned int asid = hw_pid(vma->vm_mm, cpu);
712
713 /* No need to loop here: this will always be for 1 Huge Page */
714 tlb_entry_erase(start | _PAGE_HW_SZ | asid);
715 }
716
717 local_irq_restore(flags);
718}
719
720#endif
721
722/* Read the Cache Build Confuration Registers, Decode them and save into
723 * the cpuinfo structure for later use.
724 * No Validation is done here, simply read/convert the BCRs
725 */
726void read_decode_mmu_bcr(void)
727{
728 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
729 unsigned int tmp;
730 struct bcr_mmu_1_2 {
731#ifdef CONFIG_CPU_BIG_ENDIAN
732 unsigned int ver:8, ways:4, sets:4, u_itlb:8, u_dtlb:8;
733#else
734 unsigned int u_dtlb:8, u_itlb:8, sets:4, ways:4, ver:8;
735#endif
736 } *mmu2;
737
738 struct bcr_mmu_3 {
739#ifdef CONFIG_CPU_BIG_ENDIAN
740 unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4,
741 u_itlb:4, u_dtlb:4;
742#else
743 unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4,
744 ways:4, ver:8;
745#endif
746 } *mmu3;
747
748 struct bcr_mmu_4 {
749#ifdef CONFIG_CPU_BIG_ENDIAN
750 unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1,
751 n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3;
752#else
753 /* DTLB ITLB JES JE JA */
754 unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2,
755 pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8;
756#endif
757 } *mmu4;
758
759 tmp = read_aux_reg(ARC_REG_MMU_BCR);
760 mmu->ver = (tmp >> 24);
761
762 if (is_isa_arcompact()) {
763 if (mmu->ver <= 2) {
764 mmu2 = (struct bcr_mmu_1_2 *)&tmp;
765 mmu->pg_sz_k = TO_KB(0x2000);
766 mmu->sets = 1 << mmu2->sets;
767 mmu->ways = 1 << mmu2->ways;
768 mmu->u_dtlb = mmu2->u_dtlb;
769 mmu->u_itlb = mmu2->u_itlb;
770 } else {
771 mmu3 = (struct bcr_mmu_3 *)&tmp;
772 mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
773 mmu->sets = 1 << mmu3->sets;
774 mmu->ways = 1 << mmu3->ways;
775 mmu->u_dtlb = mmu3->u_dtlb;
776 mmu->u_itlb = mmu3->u_itlb;
777 mmu->sasid = mmu3->sasid;
778 }
779 } else {
780 mmu4 = (struct bcr_mmu_4 *)&tmp;
781 mmu->pg_sz_k = 1 << (mmu4->sz0 - 1);
782 mmu->s_pg_sz_m = 1 << (mmu4->sz1 - 11);
783 mmu->sets = 64 << mmu4->n_entry;
784 mmu->ways = mmu4->n_ways * 2;
785 mmu->u_dtlb = mmu4->u_dtlb * 4;
786 mmu->u_itlb = mmu4->u_itlb * 4;
787 mmu->sasid = mmu4->sasid;
788 pae_exists = mmu->pae = mmu4->pae;
789 }
790}
791
792char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
793{
794 int n = 0;
795 struct cpuinfo_arc_mmu *p_mmu = &cpuinfo_arc700[cpu_id].mmu;
796 char super_pg[64] = "";
797
798 if (p_mmu->s_pg_sz_m)
799 scnprintf(super_pg, 64, "%dM Super Page %s",
800 p_mmu->s_pg_sz_m,
801 IS_USED_CFG(CONFIG_TRANSPARENT_HUGEPAGE));
802
803 n += scnprintf(buf + n, len - n,
804 "MMU [v%x]\t: %dk PAGE, %sJTLB %d (%dx%d), uDTLB %d, uITLB %d%s%s\n",
805 p_mmu->ver, p_mmu->pg_sz_k, super_pg,
806 p_mmu->sets * p_mmu->ways, p_mmu->sets, p_mmu->ways,
807 p_mmu->u_dtlb, p_mmu->u_itlb,
808 IS_AVAIL2(p_mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40));
809
810 return buf;
811}
812
813int pae40_exist_but_not_enab(void)
814{
815 return pae_exists && !is_pae40_enabled();
816}
817
818void arc_mmu_init(void)
819{
820 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
821 char str[256];
822 int compat = 0;
823
824 pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str)));
825
826 /*
827 * Can't be done in processor.h due to header include depenedencies
828 */
829 BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE));
830
831 /*
832 * stack top size sanity check,
833 * Can't be done in processor.h due to header include depenedencies
834 */
835 BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE));
836
837 /*
838 * Ensure that MMU features assumed by kernel exist in hardware.
839 * For older ARC700 cpus, it has to be exact match, since the MMU
840 * revisions were not backwards compatible (MMUv3 TLB layout changed
841 * so even if kernel for v2 didn't use any new cmds of v3, it would
842 * still not work.
843 * For HS cpus, MMUv4 was baseline and v5 is backwards compatible
844 * (will run older software).
845 */
846 if (is_isa_arcompact() && mmu->ver == CONFIG_ARC_MMU_VER)
847 compat = 1;
848 else if (is_isa_arcv2() && mmu->ver >= CONFIG_ARC_MMU_VER)
849 compat = 1;
850
851 if (!compat) {
852 panic("MMU ver %d doesn't match kernel built for %d...\n",
853 mmu->ver, CONFIG_ARC_MMU_VER);
854 }
855
856 if (mmu->pg_sz_k != TO_KB(PAGE_SIZE))
857 panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
858
859 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
860 mmu->s_pg_sz_m != TO_MB(HPAGE_PMD_SIZE))
861 panic("MMU Super pg size != Linux HPAGE_PMD_SIZE (%luM)\n",
862 (unsigned long)TO_MB(HPAGE_PMD_SIZE));
863
864 if (IS_ENABLED(CONFIG_ARC_HAS_PAE40) && !mmu->pae)
865 panic("Hardware doesn't support PAE40\n");
866
867 /* Enable the MMU */
868 write_aux_reg(ARC_REG_PID, MMU_ENABLE);
869
870 /* In smp we use this reg for interrupt 1 scratch */
871#ifndef CONFIG_SMP
872 /* swapper_pg_dir is the pgd for the kernel, used by vmalloc */
873 write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir);
874#endif
875
876 if (pae40_exist_but_not_enab())
877 write_aux_reg(ARC_REG_TLBPD1HI, 0);
878}
879
880/*
881 * TLB Programmer's Model uses Linear Indexes: 0 to {255, 511} for 128 x {2,4}
882 * The mapping is Column-first.
883 * --------------------- -----------
884 * |way0|way1|way2|way3| |way0|way1|
885 * --------------------- -----------
886 * [set0] | 0 | 1 | 2 | 3 | | 0 | 1 |
887 * [set1] | 4 | 5 | 6 | 7 | | 2 | 3 |
888 * ~ ~ ~ ~
889 * [set127] | 508| 509| 510| 511| | 254| 255|
890 * --------------------- -----------
891 * For normal operations we don't(must not) care how above works since
892 * MMU cmd getIndex(vaddr) abstracts that out.
893 * However for walking WAYS of a SET, we need to know this
894 */
895#define SET_WAY_TO_IDX(mmu, set, way) ((set) * mmu->ways + (way))
896
897/* Handling of Duplicate PD (TLB entry) in MMU.
898 * -Could be due to buggy customer tapeouts or obscure kernel bugs
899 * -MMU complaints not at the time of duplicate PD installation, but at the
900 * time of lookup matching multiple ways.
901 * -Ideally these should never happen - but if they do - workaround by deleting
902 * the duplicate one.
903 * -Knob to be verbose abt it.(TODO: hook them up to debugfs)
904 */
905volatile int dup_pd_silent; /* Be slient abt it or complain (default) */
906
907void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
908 struct pt_regs *regs)
909{
910 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
911 unsigned long flags;
912 int set, n_ways = mmu->ways;
913
914 n_ways = min(n_ways, 4);
915 BUG_ON(mmu->ways > 4);
916
917 local_irq_save(flags);
918
919 /* loop thru all sets of TLB */
920 for (set = 0; set < mmu->sets; set++) {
921
922 int is_valid, way;
923 unsigned int pd0[4];
924
925 /* read out all the ways of current set */
926 for (way = 0, is_valid = 0; way < n_ways; way++) {
927 write_aux_reg(ARC_REG_TLBINDEX,
928 SET_WAY_TO_IDX(mmu, set, way));
929 write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
930 pd0[way] = read_aux_reg(ARC_REG_TLBPD0);
931 is_valid |= pd0[way] & _PAGE_PRESENT;
932 pd0[way] &= PAGE_MASK;
933 }
934
935 /* If all the WAYS in SET are empty, skip to next SET */
936 if (!is_valid)
937 continue;
938
939 /* Scan the set for duplicate ways: needs a nested loop */
940 for (way = 0; way < n_ways - 1; way++) {
941
942 int n;
943
944 if (!pd0[way])
945 continue;
946
947 for (n = way + 1; n < n_ways; n++) {
948 if (pd0[way] != pd0[n])
949 continue;
950
951 if (!dup_pd_silent)
952 pr_info("Dup TLB PD0 %08x @ set %d ways %d,%d\n",
953 pd0[way], set, way, n);
954
955 /*
956 * clear entry @way and not @n.
957 * This is critical to our optimised loop
958 */
959 pd0[way] = 0;
960 write_aux_reg(ARC_REG_TLBINDEX,
961 SET_WAY_TO_IDX(mmu, set, way));
962 __tlb_entry_erase();
963 }
964 }
965 }
966
967 local_irq_restore(flags);
968}
969
970/***********************************************************************
971 * Diagnostic Routines
972 * -Called from Low Level TLB Hanlders if things don;t look good
973 **********************************************************************/
974
975#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
976
977/*
978 * Low Level ASM TLB handler calls this if it finds that HW and SW ASIDS
979 * don't match
980 */
981void print_asid_mismatch(int mm_asid, int mmu_asid, int is_fast_path)
982{
983 pr_emerg("ASID Mismatch in %s Path Handler: sw-pid=0x%x hw-pid=0x%x\n",
984 is_fast_path ? "Fast" : "Slow", mm_asid, mmu_asid);
985
986 __asm__ __volatile__("flag 1");
987}
988
989void tlb_paranoid_check(unsigned int mm_asid, unsigned long addr)
990{
991 unsigned int mmu_asid;
992
993 mmu_asid = read_aux_reg(ARC_REG_PID) & 0xff;
994
995 /*
996 * At the time of a TLB miss/installation
997 * - HW version needs to match SW version
998 * - SW needs to have a valid ASID
999 */
1000 if (addr < 0x70000000 &&
1001 ((mm_asid == MM_CTXT_NO_ASID) ||
1002 (mmu_asid != (mm_asid & MM_CTXT_ASID_MASK))))
1003 print_asid_mismatch(mm_asid, mmu_asid, 0);
1004}
1005#endif
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 */
19DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE;
20
21static int __read_mostly pae_exists;
22
23/*
24 * Utility Routine to erase a J-TLB entry
25 * Caller needs to setup Index Reg (manually or via getIndex)
26 */
27static inline void __tlb_entry_erase(void)
28{
29 write_aux_reg(ARC_REG_TLBPD1, 0);
30
31 if (is_pae40_enabled())
32 write_aux_reg(ARC_REG_TLBPD1HI, 0);
33
34 write_aux_reg(ARC_REG_TLBPD0, 0);
35 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
36}
37
38static void utlb_invalidate(void)
39{
40 write_aux_reg(ARC_REG_TLBCOMMAND, TLBIVUTLB);
41}
42
43#ifdef CONFIG_ARC_MMU_V3
44
45static inline unsigned int tlb_entry_lkup(unsigned long vaddr_n_asid)
46{
47 unsigned int idx;
48
49 write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid);
50
51 write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);
52 idx = read_aux_reg(ARC_REG_TLBINDEX);
53
54 return idx;
55}
56
57static void tlb_entry_erase(unsigned int vaddr_n_asid)
58{
59 unsigned int idx;
60
61 /* Locate the TLB entry for this vaddr + ASID */
62 idx = tlb_entry_lkup(vaddr_n_asid);
63
64 /* No error means entry found, zero it out */
65 if (likely(!(idx & TLB_LKUP_ERR))) {
66 __tlb_entry_erase();
67 } else {
68 /* Duplicate entry error */
69 WARN(idx == TLB_DUP_ERR, "Probe returned Dup PD for %x\n",
70 vaddr_n_asid);
71 }
72}
73
74static void tlb_entry_insert(unsigned int pd0, phys_addr_t pd1)
75{
76 unsigned int idx;
77
78 /*
79 * First verify if entry for this vaddr+ASID already exists
80 * This also sets up PD0 (vaddr, ASID..) for final commit
81 */
82 idx = tlb_entry_lkup(pd0);
83
84 /*
85 * If Not already present get a free slot from MMU.
86 * Otherwise, Probe would have located the entry and set INDEX Reg
87 * with existing location. This will cause Write CMD to over-write
88 * existing entry with new PD0 and PD1
89 */
90 if (likely(idx & TLB_LKUP_ERR))
91 write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);
92
93 /* setup the other half of TLB entry (pfn, rwx..) */
94 write_aux_reg(ARC_REG_TLBPD1, pd1);
95
96 /*
97 * Commit the Entry to MMU
98 * It doesn't sound safe to use the TLBWriteNI cmd here
99 * which doesn't flush uTLBs. I'd rather be safe than sorry.
100 */
101 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
102}
103
104#else /* MMUv4 */
105
106static void tlb_entry_erase(unsigned int vaddr_n_asid)
107{
108 write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid | _PAGE_PRESENT);
109 write_aux_reg(ARC_REG_TLBCOMMAND, TLBDeleteEntry);
110}
111
112static void tlb_entry_insert(unsigned int pd0, phys_addr_t pd1)
113{
114 write_aux_reg(ARC_REG_TLBPD0, pd0);
115
116 if (!is_pae40_enabled()) {
117 write_aux_reg(ARC_REG_TLBPD1, pd1);
118 } else {
119 write_aux_reg(ARC_REG_TLBPD1, pd1 & 0xFFFFFFFF);
120 write_aux_reg(ARC_REG_TLBPD1HI, (u64)pd1 >> 32);
121 }
122
123 write_aux_reg(ARC_REG_TLBCOMMAND, TLBInsertEntry);
124}
125
126#endif
127
128/*
129 * Un-conditionally (without lookup) erase the entire MMU contents
130 */
131
132noinline void local_flush_tlb_all(void)
133{
134 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
135 unsigned long flags;
136 unsigned int entry;
137 int num_tlb = mmu->sets * mmu->ways;
138
139 local_irq_save(flags);
140
141 /* Load PD0 and PD1 with template for a Blank Entry */
142 write_aux_reg(ARC_REG_TLBPD1, 0);
143
144 if (is_pae40_enabled())
145 write_aux_reg(ARC_REG_TLBPD1HI, 0);
146
147 write_aux_reg(ARC_REG_TLBPD0, 0);
148
149 for (entry = 0; entry < num_tlb; entry++) {
150 /* write this entry to the TLB */
151 write_aux_reg(ARC_REG_TLBINDEX, entry);
152 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI);
153 }
154
155 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
156 const int stlb_idx = 0x800;
157
158 /* Blank sTLB entry */
159 write_aux_reg(ARC_REG_TLBPD0, _PAGE_HW_SZ);
160
161 for (entry = stlb_idx; entry < stlb_idx + 16; entry++) {
162 write_aux_reg(ARC_REG_TLBINDEX, entry);
163 write_aux_reg(ARC_REG_TLBCOMMAND, TLBWriteNI);
164 }
165 }
166
167 utlb_invalidate();
168
169 local_irq_restore(flags);
170}
171
172/*
173 * Flush the entire MM for userland. The fastest way is to move to Next ASID
174 */
175noinline void local_flush_tlb_mm(struct mm_struct *mm)
176{
177 /*
178 * Small optimisation courtesy IA64
179 * flush_mm called during fork,exit,munmap etc, multiple times as well.
180 * Only for fork( ) do we need to move parent to a new MMU ctxt,
181 * all other cases are NOPs, hence this check.
182 */
183 if (atomic_read(&mm->mm_users) == 0)
184 return;
185
186 /*
187 * - Move to a new ASID, but only if the mm is still wired in
188 * (Android Binder ended up calling this for vma->mm != tsk->mm,
189 * causing h/w - s/w ASID to get out of sync)
190 * - Also get_new_mmu_context() new implementation allocates a new
191 * ASID only if it is not allocated already - so unallocate first
192 */
193 destroy_context(mm);
194 if (current->mm == mm)
195 get_new_mmu_context(mm);
196}
197
198/*
199 * Flush a Range of TLB entries for userland.
200 * @start is inclusive, while @end is exclusive
201 * Difference between this and Kernel Range Flush is
202 * -Here the fastest way (if range is too large) is to move to next ASID
203 * without doing any explicit Shootdown
204 * -In case of kernel Flush, entry has to be shot down explicitly
205 */
206void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
207 unsigned long end)
208{
209 const unsigned int cpu = smp_processor_id();
210 unsigned long flags;
211
212 /* If range @start to @end is more than 32 TLB entries deep,
213 * its better to move to a new ASID rather than searching for
214 * individual entries and then shooting them down
215 *
216 * The calc above is rough, doesn't account for unaligned parts,
217 * since this is heuristics based anyways
218 */
219 if (unlikely((end - start) >= PAGE_SIZE * 32)) {
220 local_flush_tlb_mm(vma->vm_mm);
221 return;
222 }
223
224 /*
225 * @start moved to page start: this alone suffices for checking
226 * loop end condition below, w/o need for aligning @end to end
227 * e.g. 2000 to 4001 will anyhow loop twice
228 */
229 start &= PAGE_MASK;
230
231 local_irq_save(flags);
232
233 if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
234 while (start < end) {
235 tlb_entry_erase(start | hw_pid(vma->vm_mm, cpu));
236 start += PAGE_SIZE;
237 }
238 }
239
240 local_irq_restore(flags);
241}
242
243/* Flush the kernel TLB entries - vmalloc/modules (Global from MMU perspective)
244 * @start, @end interpreted as kvaddr
245 * Interestingly, shared TLB entries can also be flushed using just
246 * @start,@end alone (interpreted as user vaddr), although technically SASID
247 * is also needed. However our smart TLbProbe lookup takes care of that.
248 */
249void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
250{
251 unsigned long flags;
252
253 /* exactly same as above, except for TLB entry not taking ASID */
254
255 if (unlikely((end - start) >= PAGE_SIZE * 32)) {
256 local_flush_tlb_all();
257 return;
258 }
259
260 start &= PAGE_MASK;
261
262 local_irq_save(flags);
263 while (start < end) {
264 tlb_entry_erase(start);
265 start += PAGE_SIZE;
266 }
267
268 local_irq_restore(flags);
269}
270
271/*
272 * Delete TLB entry in MMU for a given page (??? address)
273 * NOTE One TLB entry contains translation for single PAGE
274 */
275
276void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
277{
278 const unsigned int cpu = smp_processor_id();
279 unsigned long flags;
280
281 /* Note that it is critical that interrupts are DISABLED between
282 * checking the ASID and using it flush the TLB entry
283 */
284 local_irq_save(flags);
285
286 if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) {
287 tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm, cpu));
288 }
289
290 local_irq_restore(flags);
291}
292
293#ifdef CONFIG_SMP
294
295struct tlb_args {
296 struct vm_area_struct *ta_vma;
297 unsigned long ta_start;
298 unsigned long ta_end;
299};
300
301static inline void ipi_flush_tlb_page(void *arg)
302{
303 struct tlb_args *ta = arg;
304
305 local_flush_tlb_page(ta->ta_vma, ta->ta_start);
306}
307
308static inline void ipi_flush_tlb_range(void *arg)
309{
310 struct tlb_args *ta = arg;
311
312 local_flush_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
313}
314
315#ifdef CONFIG_TRANSPARENT_HUGEPAGE
316static inline void ipi_flush_pmd_tlb_range(void *arg)
317{
318 struct tlb_args *ta = arg;
319
320 local_flush_pmd_tlb_range(ta->ta_vma, ta->ta_start, ta->ta_end);
321}
322#endif
323
324static inline void ipi_flush_tlb_kernel_range(void *arg)
325{
326 struct tlb_args *ta = (struct tlb_args *)arg;
327
328 local_flush_tlb_kernel_range(ta->ta_start, ta->ta_end);
329}
330
331void flush_tlb_all(void)
332{
333 on_each_cpu((smp_call_func_t)local_flush_tlb_all, NULL, 1);
334}
335
336void flush_tlb_mm(struct mm_struct *mm)
337{
338 on_each_cpu_mask(mm_cpumask(mm), (smp_call_func_t)local_flush_tlb_mm,
339 mm, 1);
340}
341
342void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
343{
344 struct tlb_args ta = {
345 .ta_vma = vma,
346 .ta_start = uaddr
347 };
348
349 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_page, &ta, 1);
350}
351
352void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
353 unsigned long end)
354{
355 struct tlb_args ta = {
356 .ta_vma = vma,
357 .ta_start = start,
358 .ta_end = end
359 };
360
361 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_tlb_range, &ta, 1);
362}
363
364#ifdef CONFIG_TRANSPARENT_HUGEPAGE
365void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
366 unsigned long end)
367{
368 struct tlb_args ta = {
369 .ta_vma = vma,
370 .ta_start = start,
371 .ta_end = end
372 };
373
374 on_each_cpu_mask(mm_cpumask(vma->vm_mm), ipi_flush_pmd_tlb_range, &ta, 1);
375}
376#endif
377
378void flush_tlb_kernel_range(unsigned long start, unsigned long end)
379{
380 struct tlb_args ta = {
381 .ta_start = start,
382 .ta_end = end
383 };
384
385 on_each_cpu(ipi_flush_tlb_kernel_range, &ta, 1);
386}
387#endif
388
389/*
390 * Routine to create a TLB entry
391 */
392void create_tlb(struct vm_area_struct *vma, unsigned long vaddr, pte_t *ptep)
393{
394 unsigned long flags;
395 unsigned int asid_or_sasid, rwx;
396 unsigned long pd0;
397 phys_addr_t pd1;
398
399 /*
400 * create_tlb() assumes that current->mm == vma->mm, since
401 * -it ASID for TLB entry is fetched from MMU ASID reg (valid for curr)
402 * -completes the lazy write to SASID reg (again valid for curr tsk)
403 *
404 * Removing the assumption involves
405 * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.
406 * -More importantly it makes this handler inconsistent with fast-path
407 * TLB Refill handler which always deals with "current"
408 *
409 * Lets see the use cases when current->mm != vma->mm and we land here
410 * 1. execve->copy_strings()->__get_user_pages->handle_mm_fault
411 * Here VM wants to pre-install a TLB entry for user stack while
412 * current->mm still points to pre-execve mm (hence the condition).
413 * However the stack vaddr is soon relocated (randomization) and
414 * move_page_tables() tries to undo that TLB entry.
415 * Thus not creating TLB entry is not any worse.
416 *
417 * 2. ptrace(POKETEXT) causes a CoW - debugger(current) inserting a
418 * breakpoint in debugged task. Not creating a TLB now is not
419 * performance critical.
420 *
421 * Both the cases above are not good enough for code churn.
422 */
423 if (current->active_mm != vma->vm_mm)
424 return;
425
426 local_irq_save(flags);
427
428 vaddr &= PAGE_MASK;
429
430 /* update this PTE credentials */
431 pte_val(*ptep) |= (_PAGE_PRESENT | _PAGE_ACCESSED);
432
433 /* Create HW TLB(PD0,PD1) from PTE */
434
435 /* ASID for this task */
436 asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff;
437
438 pd0 = vaddr | asid_or_sasid | (pte_val(*ptep) & PTE_BITS_IN_PD0);
439
440 /*
441 * ARC MMU provides fully orthogonal access bits for K/U mode,
442 * however Linux only saves 1 set to save PTE real-estate
443 * Here we convert 3 PTE bits into 6 MMU bits:
444 * -Kernel only entries have Kr Kw Kx 0 0 0
445 * -User entries have mirrored K and U bits
446 */
447 rwx = pte_val(*ptep) & PTE_BITS_RWX;
448
449 if (pte_val(*ptep) & _PAGE_GLOBAL)
450 rwx <<= 3; /* r w x => Kr Kw Kx 0 0 0 */
451 else
452 rwx |= (rwx << 3); /* r w x => Kr Kw Kx Ur Uw Ux */
453
454 pd1 = rwx | (pte_val(*ptep) & PTE_BITS_NON_RWX_IN_PD1);
455
456 tlb_entry_insert(pd0, pd1);
457
458 local_irq_restore(flags);
459}
460
461/*
462 * Called at the end of pagefault, for a userspace mapped page
463 * -pre-install the corresponding TLB entry into MMU
464 * -Finalize the delayed D-cache flush of kernel mapping of page due to
465 * flush_dcache_page(), copy_user_page()
466 *
467 * Note that flush (when done) involves both WBACK - so physical page is
468 * in sync as well as INV - so any non-congruent aliases don't remain
469 */
470void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
471 pte_t *ptep)
472{
473 unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
474 phys_addr_t paddr = pte_val(*ptep) & PAGE_MASK_PHYS;
475 struct page *page = pfn_to_page(pte_pfn(*ptep));
476
477 create_tlb(vma, vaddr, ptep);
478
479 if (page == ZERO_PAGE(0)) {
480 return;
481 }
482
483 /*
484 * Exec page : Independent of aliasing/page-color considerations,
485 * since icache doesn't snoop dcache on ARC, any dirty
486 * K-mapping of a code page needs to be wback+inv so that
487 * icache fetch by userspace sees code correctly.
488 * !EXEC page: If K-mapping is NOT congruent to U-mapping, flush it
489 * so userspace sees the right data.
490 * (Avoids the flush for Non-exec + congruent mapping case)
491 */
492 if ((vma->vm_flags & VM_EXEC) ||
493 addr_not_cache_congruent(paddr, vaddr)) {
494
495 int dirty = !test_and_set_bit(PG_dc_clean, &page->flags);
496 if (dirty) {
497 /* wback + inv dcache lines (K-mapping) */
498 __flush_dcache_page(paddr, paddr);
499
500 /* invalidate any existing icache lines (U-mapping) */
501 if (vma->vm_flags & VM_EXEC)
502 __inv_icache_page(paddr, vaddr);
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
530void 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(vma, addr, &pte);
535}
536
537void 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 */
563void read_decode_mmu_bcr(void)
564{
565 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
566 unsigned int tmp;
567 struct bcr_mmu_3 {
568#ifdef CONFIG_CPU_BIG_ENDIAN
569 unsigned int ver:8, ways:4, sets:4, res:3, sasid:1, pg_sz:4,
570 u_itlb:4, u_dtlb:4;
571#else
572 unsigned int u_dtlb:4, u_itlb:4, pg_sz:4, sasid:1, res:3, sets:4,
573 ways:4, ver:8;
574#endif
575 } *mmu3;
576
577 struct bcr_mmu_4 {
578#ifdef CONFIG_CPU_BIG_ENDIAN
579 unsigned int ver:8, sasid:1, sz1:4, sz0:4, res:2, pae:1,
580 n_ways:2, n_entry:2, n_super:2, u_itlb:3, u_dtlb:3;
581#else
582 /* DTLB ITLB JES JE JA */
583 unsigned int u_dtlb:3, u_itlb:3, n_super:2, n_entry:2, n_ways:2,
584 pae:1, res:2, sz0:4, sz1:4, sasid:1, ver:8;
585#endif
586 } *mmu4;
587
588 tmp = read_aux_reg(ARC_REG_MMU_BCR);
589 mmu->ver = (tmp >> 24);
590
591 if (is_isa_arcompact() && mmu->ver == 3) {
592 mmu3 = (struct bcr_mmu_3 *)&tmp;
593 mmu->pg_sz_k = 1 << (mmu3->pg_sz - 1);
594 mmu->sets = 1 << mmu3->sets;
595 mmu->ways = 1 << mmu3->ways;
596 mmu->u_dtlb = mmu3->u_dtlb;
597 mmu->u_itlb = mmu3->u_itlb;
598 mmu->sasid = mmu3->sasid;
599 } else {
600 mmu4 = (struct bcr_mmu_4 *)&tmp;
601 mmu->pg_sz_k = 1 << (mmu4->sz0 - 1);
602 mmu->s_pg_sz_m = 1 << (mmu4->sz1 - 11);
603 mmu->sets = 64 << mmu4->n_entry;
604 mmu->ways = mmu4->n_ways * 2;
605 mmu->u_dtlb = mmu4->u_dtlb * 4;
606 mmu->u_itlb = mmu4->u_itlb * 4;
607 mmu->sasid = mmu4->sasid;
608 pae_exists = mmu->pae = mmu4->pae;
609 }
610}
611
612char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
613{
614 int n = 0;
615 struct cpuinfo_arc_mmu *p_mmu = &cpuinfo_arc700[cpu_id].mmu;
616 char super_pg[64] = "";
617
618 if (p_mmu->s_pg_sz_m)
619 scnprintf(super_pg, 64, "%dM Super Page %s",
620 p_mmu->s_pg_sz_m,
621 IS_USED_CFG(CONFIG_TRANSPARENT_HUGEPAGE));
622
623 n += scnprintf(buf + n, len - n,
624 "MMU [v%x]\t: %dk PAGE, %s, swalk %d lvl, JTLB %d (%dx%d), uDTLB %d, uITLB %d%s%s\n",
625 p_mmu->ver, p_mmu->pg_sz_k, super_pg, CONFIG_PGTABLE_LEVELS,
626 p_mmu->sets * p_mmu->ways, p_mmu->sets, p_mmu->ways,
627 p_mmu->u_dtlb, p_mmu->u_itlb,
628 IS_AVAIL2(p_mmu->pae, ", PAE40 ", CONFIG_ARC_HAS_PAE40));
629
630 return buf;
631}
632
633int pae40_exist_but_not_enab(void)
634{
635 return pae_exists && !is_pae40_enabled();
636}
637
638void arc_mmu_init(void)
639{
640 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
641 char str[256];
642 int compat = 0;
643
644 pr_info("%s", arc_mmu_mumbojumbo(0, str, sizeof(str)));
645
646 /*
647 * Can't be done in processor.h due to header include dependencies
648 */
649 BUILD_BUG_ON(!IS_ALIGNED((CONFIG_ARC_KVADDR_SIZE << 20), PMD_SIZE));
650
651 /*
652 * stack top size sanity check,
653 * Can't be done in processor.h due to header include dependencies
654 */
655 BUILD_BUG_ON(!IS_ALIGNED(STACK_TOP, PMD_SIZE));
656
657 /*
658 * Ensure that MMU features assumed by kernel exist in hardware.
659 * - For older ARC700 cpus, only v3 supported
660 * - For HS cpus, v4 was baseline and v5 is backwards compatible
661 * (will run older software).
662 */
663 if (is_isa_arcompact() && mmu->ver == 3)
664 compat = 1;
665 else if (is_isa_arcv2() && mmu->ver >= 4)
666 compat = 1;
667
668 if (!compat)
669 panic("MMU ver %d doesn't match kernel built for\n", mmu->ver);
670
671 if (mmu->pg_sz_k != TO_KB(PAGE_SIZE))
672 panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
673
674 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
675 mmu->s_pg_sz_m != TO_MB(HPAGE_PMD_SIZE))
676 panic("MMU Super pg size != Linux HPAGE_PMD_SIZE (%luM)\n",
677 (unsigned long)TO_MB(HPAGE_PMD_SIZE));
678
679 if (IS_ENABLED(CONFIG_ARC_HAS_PAE40) && !mmu->pae)
680 panic("Hardware doesn't support PAE40\n");
681
682 /* Enable the MMU with ASID 0 */
683 mmu_setup_asid(NULL, 0);
684
685 /* cache the pgd pointer in MMU SCRATCH reg (ARCv2 only) */
686 mmu_setup_pgd(NULL, swapper_pg_dir);
687
688 if (pae40_exist_but_not_enab())
689 write_aux_reg(ARC_REG_TLBPD1HI, 0);
690}
691
692/*
693 * TLB Programmer's Model uses Linear Indexes: 0 to {255, 511} for 128 x {2,4}
694 * The mapping is Column-first.
695 * --------------------- -----------
696 * |way0|way1|way2|way3| |way0|way1|
697 * --------------------- -----------
698 * [set0] | 0 | 1 | 2 | 3 | | 0 | 1 |
699 * [set1] | 4 | 5 | 6 | 7 | | 2 | 3 |
700 * ~ ~ ~ ~
701 * [set127] | 508| 509| 510| 511| | 254| 255|
702 * --------------------- -----------
703 * For normal operations we don't(must not) care how above works since
704 * MMU cmd getIndex(vaddr) abstracts that out.
705 * However for walking WAYS of a SET, we need to know this
706 */
707#define SET_WAY_TO_IDX(mmu, set, way) ((set) * mmu->ways + (way))
708
709/* Handling of Duplicate PD (TLB entry) in MMU.
710 * -Could be due to buggy customer tapeouts or obscure kernel bugs
711 * -MMU complaints not at the time of duplicate PD installation, but at the
712 * time of lookup matching multiple ways.
713 * -Ideally these should never happen - but if they do - workaround by deleting
714 * the duplicate one.
715 * -Knob to be verbose abt it.(TODO: hook them up to debugfs)
716 */
717volatile int dup_pd_silent; /* Be silent abt it or complain (default) */
718
719void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
720 struct pt_regs *regs)
721{
722 struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
723 unsigned long flags;
724 int set, n_ways = mmu->ways;
725
726 n_ways = min(n_ways, 4);
727 BUG_ON(mmu->ways > 4);
728
729 local_irq_save(flags);
730
731 /* loop thru all sets of TLB */
732 for (set = 0; set < mmu->sets; set++) {
733
734 int is_valid, way;
735 unsigned int pd0[4];
736
737 /* read out all the ways of current set */
738 for (way = 0, is_valid = 0; way < n_ways; way++) {
739 write_aux_reg(ARC_REG_TLBINDEX,
740 SET_WAY_TO_IDX(mmu, set, way));
741 write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
742 pd0[way] = read_aux_reg(ARC_REG_TLBPD0);
743 is_valid |= pd0[way] & _PAGE_PRESENT;
744 pd0[way] &= PAGE_MASK;
745 }
746
747 /* If all the WAYS in SET are empty, skip to next SET */
748 if (!is_valid)
749 continue;
750
751 /* Scan the set for duplicate ways: needs a nested loop */
752 for (way = 0; way < n_ways - 1; way++) {
753
754 int n;
755
756 if (!pd0[way])
757 continue;
758
759 for (n = way + 1; n < n_ways; n++) {
760 if (pd0[way] != pd0[n])
761 continue;
762
763 if (!dup_pd_silent)
764 pr_info("Dup TLB PD0 %08x @ set %d ways %d,%d\n",
765 pd0[way], set, way, n);
766
767 /*
768 * clear entry @way and not @n.
769 * This is critical to our optimised loop
770 */
771 pd0[way] = 0;
772 write_aux_reg(ARC_REG_TLBINDEX,
773 SET_WAY_TO_IDX(mmu, set, way));
774 __tlb_entry_erase();
775 }
776 }
777 }
778
779 local_irq_restore(flags);
780}