tlb.c revision 24603fdd19d978fcc0d089d92370ee1aa3a71e84
1/*
2 * TLB Management (flush/create/diagnostics) for ARC700
3 *
4 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * vineetg: Aug 2011
11 *  -Reintroduce duplicate PD fixup - some customer chips still have the issue
12 *
13 * vineetg: May 2011
14 *  -No need to flush_cache_page( ) for each call to update_mmu_cache()
15 *   some of the LMBench tests improved amazingly
16 *      = page-fault thrice as fast (75 usec to 28 usec)
17 *      = mmap twice as fast (9.6 msec to 4.6 msec),
18 *      = fork (5.3 msec to 3.7 msec)
19 *
20 * vineetg: April 2011 :
21 *  -MMU v3: PD{0,1} bits layout changed: They don't overlap anymore,
22 *      helps avoid a shift when preparing PD0 from PTE
23 *
24 * vineetg: April 2011 : Preparing for MMU V3
25 *  -MMU v2/v3 BCRs decoded differently
26 *  -Remove TLB_SIZE hardcoding as it's variable now: 256 or 512
27 *  -tlb_entry_erase( ) can be void
28 *  -local_flush_tlb_range( ):
29 *      = need not "ceil" @end
30 *      = walks MMU only if range spans < 32 entries, as opposed to 256
31 *
32 * Vineetg: Sept 10th 2008
33 *  -Changes related to MMU v2 (Rel 4.8)
34 *
35 * Vineetg: Aug 29th 2008
36 *  -In TLB Flush operations (Metal Fix MMU) there is a explict command to
37 *    flush Micro-TLBS. If TLB Index Reg is invalid prior to TLBIVUTLB cmd,
38 *    it fails. Thus need to load it with ANY valid value before invoking
39 *    TLBIVUTLB cmd
40 *
41 * Vineetg: Aug 21th 2008:
42 *  -Reduced the duration of IRQ lockouts in TLB Flush routines
43 *  -Multiple copies of TLB erase code seperated into a "single" function
44 *  -In TLB Flush routines, interrupt disabling moved UP to retrieve ASID
45 *       in interrupt-safe region.
46 *
47 * Vineetg: April 23rd Bug #93131
48 *    Problem: tlb_flush_kernel_range() doesnt do anything if the range to
49 *              flush is more than the size of TLB itself.
50 *
51 * Rahul Trivedi : Codito Technologies 2004
52 */
53
54#include <linux/module.h>
55#include <asm/arcregs.h>
56#include <asm/setup.h>
57#include <asm/mmu_context.h>
58#include <asm/tlb.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/* A copy of the ASID from the PID reg is kept in asid_cache */
101int asid_cache = FIRST_ASID;
102
103/* ASID to mm struct mapping. We have one extra entry corresponding to
104 * NO_ASID to save us a compare when clearing the mm entry for old asid
105 * see get_new_mmu_context (asm-arc/mmu_context.h)
106 */
107struct mm_struct *asid_mm_map[NUM_ASID + 1];
108
109/*
110 * Utility Routine to erase a J-TLB entry
111 * The procedure is to look it up in the MMU. If found, ERASE it by
112 *  issuing a TlbWrite CMD with PD0 = PD1 = 0
113 */
114
115static void __tlb_entry_erase(void)
116{
117	write_aux_reg(ARC_REG_TLBPD1, 0);
118	write_aux_reg(ARC_REG_TLBPD0, 0);
119	write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
120}
121
122static void tlb_entry_erase(unsigned int vaddr_n_asid)
123{
124	unsigned int idx;
125
126	/* Locate the TLB entry for this vaddr + ASID */
127	write_aux_reg(ARC_REG_TLBPD0, vaddr_n_asid);
128	write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);
129	idx = read_aux_reg(ARC_REG_TLBINDEX);
130
131	/* No error means entry found, zero it out */
132	if (likely(!(idx & TLB_LKUP_ERR))) {
133		__tlb_entry_erase();
134	} else {		/* Some sort of Error */
135
136		/* Duplicate entry error */
137		if (idx & 0x1) {
138			/* TODO we need to handle this case too */
139			pr_emerg("unhandled Duplicate flush for %x\n",
140			       vaddr_n_asid);
141		}
142		/* else entry not found so nothing to do */
143	}
144}
145
146/****************************************************************************
147 * ARC700 MMU caches recently used J-TLB entries (RAM) as uTLBs (FLOPs)
148 *
149 * New IVUTLB cmd in MMU v2 explictly invalidates the uTLB
150 *
151 * utlb_invalidate ( )
152 *  -For v2 MMU calls Flush uTLB Cmd
153 *  -For v1 MMU does nothing (except for Metal Fix v1 MMU)
154 *      This is because in v1 TLBWrite itself invalidate uTLBs
155 ***************************************************************************/
156
157static void utlb_invalidate(void)
158{
159#if (CONFIG_ARC_MMU_VER >= 2)
160
161#if (CONFIG_ARC_MMU_VER < 3)
162	/* MMU v2 introduced the uTLB Flush command.
163	 * There was however an obscure hardware bug, where uTLB flush would
164	 * fail when a prior probe for J-TLB (both totally unrelated) would
165	 * return lkup err - because the entry didnt exist in MMU.
166	 * The Workround was to set Index reg with some valid value, prior to
167	 * flush. This was fixed in MMU v3 hence not needed any more
168	 */
169	unsigned int idx;
170
171	/* make sure INDEX Reg is valid */
172	idx = read_aux_reg(ARC_REG_TLBINDEX);
173
174	/* If not write some dummy val */
175	if (unlikely(idx & TLB_LKUP_ERR))
176		write_aux_reg(ARC_REG_TLBINDEX, 0xa);
177#endif
178
179	write_aux_reg(ARC_REG_TLBCOMMAND, TLBIVUTLB);
180#endif
181
182}
183
184/*
185 * Un-conditionally (without lookup) erase the entire MMU contents
186 */
187
188noinline void local_flush_tlb_all(void)
189{
190	unsigned long flags;
191	unsigned int entry;
192	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
193
194	local_irq_save(flags);
195
196	/* Load PD0 and PD1 with template for a Blank Entry */
197	write_aux_reg(ARC_REG_TLBPD1, 0);
198	write_aux_reg(ARC_REG_TLBPD0, 0);
199
200	for (entry = 0; entry < mmu->num_tlb; entry++) {
201		/* write this entry to the TLB */
202		write_aux_reg(ARC_REG_TLBINDEX, entry);
203		write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
204	}
205
206	utlb_invalidate();
207
208	local_irq_restore(flags);
209}
210
211/*
212 * Flush the entrie MM for userland. The fastest way is to move to Next ASID
213 */
214noinline void local_flush_tlb_mm(struct mm_struct *mm)
215{
216	/*
217	 * Small optimisation courtesy IA64
218	 * flush_mm called during fork,exit,munmap etc, multiple times as well.
219	 * Only for fork( ) do we need to move parent to a new MMU ctxt,
220	 * all other cases are NOPs, hence this check.
221	 */
222	if (atomic_read(&mm->mm_users) == 0)
223		return;
224
225	/*
226	 * Workaround for Android weirdism:
227	 * A binder VMA could end up in a task such that vma->mm != tsk->mm
228	 * old code would cause h/w - s/w ASID to get out of sync
229	 */
230	if (current->mm != mm)
231		destroy_context(mm);
232	else
233		get_new_mmu_context(mm);
234}
235
236/*
237 * Flush a Range of TLB entries for userland.
238 * @start is inclusive, while @end is exclusive
239 * Difference between this and Kernel Range Flush is
240 *  -Here the fastest way (if range is too large) is to move to next ASID
241 *      without doing any explicit Shootdown
242 *  -In case of kernel Flush, entry has to be shot down explictly
243 */
244void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
245			   unsigned long end)
246{
247	unsigned long flags;
248	unsigned int asid;
249
250	/* If range @start to @end is more than 32 TLB entries deep,
251	 * its better to move to a new ASID rather than searching for
252	 * individual entries and then shooting them down
253	 *
254	 * The calc above is rough, doesn't account for unaligned parts,
255	 * since this is heuristics based anyways
256	 */
257	if (unlikely((end - start) >= PAGE_SIZE * 32)) {
258		local_flush_tlb_mm(vma->vm_mm);
259		return;
260	}
261
262	/*
263	 * @start moved to page start: this alone suffices for checking
264	 * loop end condition below, w/o need for aligning @end to end
265	 * e.g. 2000 to 4001 will anyhow loop twice
266	 */
267	start &= PAGE_MASK;
268
269	local_irq_save(flags);
270	asid = vma->vm_mm->context.asid;
271
272	if (asid != NO_ASID) {
273		while (start < end) {
274			tlb_entry_erase(start | (asid & 0xff));
275			start += PAGE_SIZE;
276		}
277	}
278
279	utlb_invalidate();
280
281	local_irq_restore(flags);
282}
283
284/* Flush the kernel TLB entries - vmalloc/modules (Global from MMU perspective)
285 *  @start, @end interpreted as kvaddr
286 * Interestingly, shared TLB entries can also be flushed using just
287 * @start,@end alone (interpreted as user vaddr), although technically SASID
288 * is also needed. However our smart TLbProbe lookup takes care of that.
289 */
290void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
291{
292	unsigned long flags;
293
294	/* exactly same as above, except for TLB entry not taking ASID */
295
296	if (unlikely((end - start) >= PAGE_SIZE * 32)) {
297		local_flush_tlb_all();
298		return;
299	}
300
301	start &= PAGE_MASK;
302
303	local_irq_save(flags);
304	while (start < end) {
305		tlb_entry_erase(start);
306		start += PAGE_SIZE;
307	}
308
309	utlb_invalidate();
310
311	local_irq_restore(flags);
312}
313
314/*
315 * Delete TLB entry in MMU for a given page (??? address)
316 * NOTE One TLB entry contains translation for single PAGE
317 */
318
319void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
320{
321	unsigned long flags;
322
323	/* Note that it is critical that interrupts are DISABLED between
324	 * checking the ASID and using it flush the TLB entry
325	 */
326	local_irq_save(flags);
327
328	if (vma->vm_mm->context.asid != NO_ASID) {
329		tlb_entry_erase((page & PAGE_MASK) |
330				(vma->vm_mm->context.asid & 0xff));
331		utlb_invalidate();
332	}
333
334	local_irq_restore(flags);
335}
336
337/*
338 * Routine to create a TLB entry
339 */
340void create_tlb(struct vm_area_struct *vma, unsigned long address, pte_t *ptep)
341{
342	unsigned long flags;
343	unsigned int idx, asid_or_sasid;
344	unsigned long pd0_flags;
345
346	/*
347	 * create_tlb() assumes that current->mm == vma->mm, since
348	 * -it ASID for TLB entry is fetched from MMU ASID reg (valid for curr)
349	 * -completes the lazy write to SASID reg (again valid for curr tsk)
350	 *
351	 * Removing the assumption involves
352	 * -Using vma->mm->context{ASID,SASID}, as opposed to MMU reg.
353	 * -Fix the TLB paranoid debug code to not trigger false negatives.
354	 * -More importantly it makes this handler inconsistent with fast-path
355	 *  TLB Refill handler which always deals with "current"
356	 *
357	 * Lets see the use cases when current->mm != vma->mm and we land here
358	 *  1. execve->copy_strings()->__get_user_pages->handle_mm_fault
359	 *     Here VM wants to pre-install a TLB entry for user stack while
360	 *     current->mm still points to pre-execve mm (hence the condition).
361	 *     However the stack vaddr is soon relocated (randomization) and
362	 *     move_page_tables() tries to undo that TLB entry.
363	 *     Thus not creating TLB entry is not any worse.
364	 *
365	 *  2. ptrace(POKETEXT) causes a CoW - debugger(current) inserting a
366	 *     breakpoint in debugged task. Not creating a TLB now is not
367	 *     performance critical.
368	 *
369	 * Both the cases above are not good enough for code churn.
370	 */
371	if (current->active_mm != vma->vm_mm)
372		return;
373
374	local_irq_save(flags);
375
376	tlb_paranoid_check(vma->vm_mm->context.asid, address);
377
378	address &= PAGE_MASK;
379
380	/* update this PTE credentials */
381	pte_val(*ptep) |= (_PAGE_PRESENT | _PAGE_ACCESSED);
382
383	/* Create HW TLB entry Flags (in PD0) from PTE Flags */
384#if (CONFIG_ARC_MMU_VER <= 2)
385	pd0_flags = ((pte_val(*ptep) & PTE_BITS_IN_PD0) >> 1);
386#else
387	pd0_flags = ((pte_val(*ptep) & PTE_BITS_IN_PD0));
388#endif
389
390	/* ASID for this task */
391	asid_or_sasid = read_aux_reg(ARC_REG_PID) & 0xff;
392
393	write_aux_reg(ARC_REG_TLBPD0, address | pd0_flags | asid_or_sasid);
394
395	/* Load remaining info in PD1 (Page Frame Addr and Kx/Kw/Kr Flags) */
396	write_aux_reg(ARC_REG_TLBPD1, (pte_val(*ptep) & PTE_BITS_IN_PD1));
397
398	/* First verify if entry for this vaddr+ASID already exists */
399	write_aux_reg(ARC_REG_TLBCOMMAND, TLBProbe);
400	idx = read_aux_reg(ARC_REG_TLBINDEX);
401
402	/*
403	 * If Not already present get a free slot from MMU.
404	 * Otherwise, Probe would have located the entry and set INDEX Reg
405	 * with existing location. This will cause Write CMD to over-write
406	 * existing entry with new PD0 and PD1
407	 */
408	if (likely(idx & TLB_LKUP_ERR))
409		write_aux_reg(ARC_REG_TLBCOMMAND, TLBGetIndex);
410
411	/*
412	 * Commit the Entry to MMU
413	 * It doesnt sound safe to use the TLBWriteNI cmd here
414	 * which doesn't flush uTLBs. I'd rather be safe than sorry.
415	 */
416	write_aux_reg(ARC_REG_TLBCOMMAND, TLBWrite);
417
418	local_irq_restore(flags);
419}
420
421/* arch hook called by core VM at the end of handle_mm_fault( ),
422 * when a new PTE is entered in Page Tables or an existing one
423 * is modified. We aggresively pre-install a TLB entry
424 */
425void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
426		      pte_t *ptep)
427{
428	unsigned long vaddr = vaddr_unaligned & PAGE_MASK;
429
430	create_tlb(vma, vaddr, ptep);
431
432	/* icache doesn't snoop dcache, thus needs to be made coherent here */
433	if (vma->vm_flags & VM_EXEC) {
434		unsigned long paddr =  pte_val(*ptep) & PAGE_MASK;
435		__inv_icache_page(paddr, vaddr);
436	}
437}
438
439/* Read the Cache Build Confuration Registers, Decode them and save into
440 * the cpuinfo structure for later use.
441 * No Validation is done here, simply read/convert the BCRs
442 */
443void __cpuinit read_decode_mmu_bcr(void)
444{
445	unsigned int tmp;
446	struct bcr_mmu_1_2 *mmu2;	/* encoded MMU2 attr */
447	struct bcr_mmu_3 *mmu3;		/* encoded MMU3 attr */
448	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
449
450	tmp = read_aux_reg(ARC_REG_MMU_BCR);
451	mmu->ver = (tmp >> 24);
452
453	if (mmu->ver <= 2) {
454		mmu2 = (struct bcr_mmu_1_2 *)&tmp;
455		mmu->pg_sz = PAGE_SIZE;
456		mmu->sets = 1 << mmu2->sets;
457		mmu->ways = 1 << mmu2->ways;
458		mmu->u_dtlb = mmu2->u_dtlb;
459		mmu->u_itlb = mmu2->u_itlb;
460	} else {
461		mmu3 = (struct bcr_mmu_3 *)&tmp;
462		mmu->pg_sz = 512 << mmu3->pg_sz;
463		mmu->sets = 1 << mmu3->sets;
464		mmu->ways = 1 << mmu3->ways;
465		mmu->u_dtlb = mmu3->u_dtlb;
466		mmu->u_itlb = mmu3->u_itlb;
467	}
468
469	mmu->num_tlb = mmu->sets * mmu->ways;
470}
471
472char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
473{
474	int n = 0;
475	struct cpuinfo_arc_mmu *p_mmu = &cpuinfo_arc700[cpu_id].mmu;
476
477	n += scnprintf(buf + n, len - n, "ARC700 MMU [v%x]\t: %dk PAGE, ",
478		       p_mmu->ver, TO_KB(p_mmu->pg_sz));
479
480	n += scnprintf(buf + n, len - n,
481		       "J-TLB %d (%dx%d), uDTLB %d, uITLB %d, %s\n",
482		       p_mmu->num_tlb, p_mmu->sets, p_mmu->ways,
483		       p_mmu->u_dtlb, p_mmu->u_itlb,
484		       __CONFIG_ARC_MMU_SASID_VAL ? "SASID" : "");
485
486	return buf;
487}
488
489void __cpuinit arc_mmu_init(void)
490{
491	char str[256];
492	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
493
494	printk(arc_mmu_mumbojumbo(0, str, sizeof(str)));
495
496	/* For efficiency sake, kernel is compile time built for a MMU ver
497	 * This must match the hardware it is running on.
498	 * Linux built for MMU V2, if run on MMU V1 will break down because V1
499	 *  hardware doesn't understand cmds such as WriteNI, or IVUTLB
500	 * On the other hand, Linux built for V1 if run on MMU V2 will do
501	 *   un-needed workarounds to prevent memcpy thrashing.
502	 * Similarly MMU V3 has new features which won't work on older MMU
503	 */
504	if (mmu->ver != CONFIG_ARC_MMU_VER) {
505		panic("MMU ver %d doesn't match kernel built for %d...\n",
506		      mmu->ver, CONFIG_ARC_MMU_VER);
507	}
508
509	if (mmu->pg_sz != PAGE_SIZE)
510		panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
511
512	/*
513	 * ASID mgmt data structures are compile time init
514	 *  asid_cache = FIRST_ASID and asid_mm_map[] all zeroes
515	 */
516
517	local_flush_tlb_all();
518
519	/* Enable the MMU */
520	write_aux_reg(ARC_REG_PID, MMU_ENABLE);
521
522	/* In smp we use this reg for interrupt 1 scratch */
523#ifndef CONFIG_SMP
524	/* swapper_pg_dir is the pgd for the kernel, used by vmalloc */
525	write_aux_reg(ARC_REG_SCRATCH_DATA0, swapper_pg_dir);
526#endif
527}
528
529/*
530 * TLB Programmer's Model uses Linear Indexes: 0 to {255, 511} for 128 x {2,4}
531 * The mapping is Column-first.
532 *		---------------------	-----------
533 *		|way0|way1|way2|way3|	|way0|way1|
534 *		---------------------	-----------
535 * [set0]	|  0 |  1 |  2 |  3 |	|  0 |  1 |
536 * [set1]	|  4 |  5 |  6 |  7 |	|  2 |  3 |
537 *		~		    ~	~	  ~
538 * [set127]	| 508| 509| 510| 511|	| 254| 255|
539 *		---------------------	-----------
540 * For normal operations we don't(must not) care how above works since
541 * MMU cmd getIndex(vaddr) abstracts that out.
542 * However for walking WAYS of a SET, we need to know this
543 */
544#define SET_WAY_TO_IDX(mmu, set, way)  ((set) * mmu->ways + (way))
545
546/* Handling of Duplicate PD (TLB entry) in MMU.
547 * -Could be due to buggy customer tapeouts or obscure kernel bugs
548 * -MMU complaints not at the time of duplicate PD installation, but at the
549 *      time of lookup matching multiple ways.
550 * -Ideally these should never happen - but if they do - workaround by deleting
551 *      the duplicate one.
552 * -Knob to be verbose abt it.(TODO: hook them up to debugfs)
553 */
554volatile int dup_pd_verbose = 1;/* Be slient abt it or complain (default) */
555
556void do_tlb_overlap_fault(unsigned long cause, unsigned long address,
557			  struct pt_regs *regs)
558{
559	int set, way, n;
560	unsigned int pd0[4], pd1[4];	/* assume max 4 ways */
561	unsigned long flags, is_valid;
562	struct cpuinfo_arc_mmu *mmu = &cpuinfo_arc700[smp_processor_id()].mmu;
563
564	local_irq_save(flags);
565
566	/* re-enable the MMU */
567	write_aux_reg(ARC_REG_PID, MMU_ENABLE | read_aux_reg(ARC_REG_PID));
568
569	/* loop thru all sets of TLB */
570	for (set = 0; set < mmu->sets; set++) {
571
572		/* read out all the ways of current set */
573		for (way = 0, is_valid = 0; way < mmu->ways; way++) {
574			write_aux_reg(ARC_REG_TLBINDEX,
575					  SET_WAY_TO_IDX(mmu, set, way));
576			write_aux_reg(ARC_REG_TLBCOMMAND, TLBRead);
577			pd0[way] = read_aux_reg(ARC_REG_TLBPD0);
578			pd1[way] = read_aux_reg(ARC_REG_TLBPD1);
579			is_valid |= pd0[way] & _PAGE_PRESENT;
580		}
581
582		/* If all the WAYS in SET are empty, skip to next SET */
583		if (!is_valid)
584			continue;
585
586		/* Scan the set for duplicate ways: needs a nested loop */
587		for (way = 0; way < mmu->ways; way++) {
588			if (!pd0[way])
589				continue;
590
591			for (n = way + 1; n < mmu->ways; n++) {
592				if ((pd0[way] & PAGE_MASK) ==
593				    (pd0[n] & PAGE_MASK)) {
594
595					if (dup_pd_verbose) {
596						pr_info("Duplicate PD's @"
597							"[%d:%d]/[%d:%d]\n",
598						     set, way, set, n);
599						pr_info("TLBPD0[%u]: %08x\n",
600						     way, pd0[way]);
601					}
602
603					/*
604					 * clear entry @way and not @n. This is
605					 * critical to our optimised loop
606					 */
607					pd0[way] = pd1[way] = 0;
608					write_aux_reg(ARC_REG_TLBINDEX,
609						SET_WAY_TO_IDX(mmu, set, way));
610					__tlb_entry_erase();
611				}
612			}
613		}
614	}
615
616	local_irq_restore(flags);
617}
618
619/***********************************************************************
620 * Diagnostic Routines
621 *  -Called from Low Level TLB Hanlders if things don;t look good
622 **********************************************************************/
623
624#ifdef CONFIG_ARC_DBG_TLB_PARANOIA
625
626/*
627 * Low Level ASM TLB handler calls this if it finds that HW and SW ASIDS
628 * don't match
629 */
630void print_asid_mismatch(int is_fast_path)
631{
632	int pid_sw, pid_hw;
633	pid_sw = current->active_mm->context.asid;
634	pid_hw = read_aux_reg(ARC_REG_PID) & 0xff;
635
636	pr_emerg("ASID Mismatch in %s Path Handler: sw-pid=0x%x hw-pid=0x%x\n",
637	       is_fast_path ? "Fast" : "Slow", pid_sw, pid_hw);
638
639	__asm__ __volatile__("flag 1");
640}
641
642void tlb_paranoid_check(unsigned int pid_sw, unsigned long addr)
643{
644	unsigned int pid_hw;
645
646	pid_hw = read_aux_reg(ARC_REG_PID) & 0xff;
647
648	if (addr < 0x70000000 && ((pid_hw != pid_sw) || (pid_sw == NO_ASID)))
649		print_asid_mismatch(0);
650}
651#endif
652