xref: /kernel/linux/linux-6.6/arch/sparc/mm/tlb.c (revision 62306a36) 
1// SPDX-License-Identifier: GPL-2.0
2/* arch/sparc64/mm/tlb.c
3 *
4 * Copyright (C) 2004 David S. Miller <davem@redhat.com>
5 */
6
7#include <linux/kernel.h>
8#include <linux/percpu.h>
9#include <linux/mm.h>
10#include <linux/swap.h>
11#include <linux/preempt.h>
12#include <linux/pagemap.h>
13
14#include <asm/tlbflush.h>
15#include <asm/cacheflush.h>
16#include <asm/mmu_context.h>
17#include <asm/tlb.h>
18
19/* Heavily inspired by the ppc64 code.  */
20
21static DEFINE_PER_CPU(struct tlb_batch, tlb_batch);
22
23void flush_tlb_pending(void)
24{
25	struct tlb_batch *tb = &get_cpu_var(tlb_batch);
26	struct mm_struct *mm = tb->mm;
27
28	if (!tb->tlb_nr)
29		goto out;
30
31	flush_tsb_user(tb);
32
33	if (CTX_VALID(mm->context)) {
34		if (tb->tlb_nr == 1) {
35			global_flush_tlb_page(mm, tb->vaddrs[0]);
36		} else {
37#ifdef CONFIG_SMP
38			smp_flush_tlb_pending(tb->mm, tb->tlb_nr,
39					      &tb->vaddrs[0]);
40#else
41			__flush_tlb_pending(CTX_HWBITS(tb->mm->context),
42					    tb->tlb_nr, &tb->vaddrs[0]);
43#endif
44		}
45	}
46
47	tb->tlb_nr = 0;
48
49out:
50	put_cpu_var(tlb_batch);
51}
52
53void arch_enter_lazy_mmu_mode(void)
54{
55	struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
56
57	tb->active = 1;
58}
59
60void arch_leave_lazy_mmu_mode(void)
61{
62	struct tlb_batch *tb = this_cpu_ptr(&tlb_batch);
63
64	if (tb->tlb_nr)
65		flush_tlb_pending();
66	tb->active = 0;
67}
68
69static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,
70			      bool exec, unsigned int hugepage_shift)
71{
72	struct tlb_batch *tb = &get_cpu_var(tlb_batch);
73	unsigned long nr;
74
75	vaddr &= PAGE_MASK;
76	if (exec)
77		vaddr |= 0x1UL;
78
79	nr = tb->tlb_nr;
80
81	if (unlikely(nr != 0 && mm != tb->mm)) {
82		flush_tlb_pending();
83		nr = 0;
84	}
85
86	if (!tb->active) {
87		flush_tsb_user_page(mm, vaddr, hugepage_shift);
88		global_flush_tlb_page(mm, vaddr);
89		goto out;
90	}
91
92	if (nr == 0) {
93		tb->mm = mm;
94		tb->hugepage_shift = hugepage_shift;
95	}
96
97	if (tb->hugepage_shift != hugepage_shift) {
98		flush_tlb_pending();
99		tb->hugepage_shift = hugepage_shift;
100		nr = 0;
101	}
102
103	tb->vaddrs[nr] = vaddr;
104	tb->tlb_nr = ++nr;
105	if (nr >= TLB_BATCH_NR)
106		flush_tlb_pending();
107
108out:
109	put_cpu_var(tlb_batch);
110}
111
112void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
113		   pte_t *ptep, pte_t orig, int fullmm,
114		   unsigned int hugepage_shift)
115{
116	if (tlb_type != hypervisor &&
117	    pte_dirty(orig)) {
118		unsigned long paddr, pfn = pte_pfn(orig);
119		struct address_space *mapping;
120		struct page *page;
121		struct folio *folio;
122
123		if (!pfn_valid(pfn))
124			goto no_cache_flush;
125
126		page = pfn_to_page(pfn);
127		if (PageReserved(page))
128			goto no_cache_flush;
129
130		/* A real file page? */
131		folio = page_folio(page);
132		mapping = folio_flush_mapping(folio);
133		if (!mapping)
134			goto no_cache_flush;
135
136		paddr = (unsigned long) page_address(page);
137		if ((paddr ^ vaddr) & (1 << 13))
138			flush_dcache_folio_all(mm, folio);
139	}
140
141no_cache_flush:
142	if (!fullmm)
143		tlb_batch_add_one(mm, vaddr, pte_exec(orig), hugepage_shift);
144}
145
146#ifdef CONFIG_TRANSPARENT_HUGEPAGE
147static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
148			       pmd_t pmd)
149{
150	unsigned long end;
151	pte_t *pte;
152
153	pte = pte_offset_map(&pmd, vaddr);
154	if (!pte)
155		return;
156	end = vaddr + HPAGE_SIZE;
157	while (vaddr < end) {
158		if (pte_val(*pte) & _PAGE_VALID) {
159			bool exec = pte_exec(*pte);
160
161			tlb_batch_add_one(mm, vaddr, exec, PAGE_SHIFT);
162		}
163		pte++;
164		vaddr += PAGE_SIZE;
165	}
166	pte_unmap(pte);
167}
168
169
170static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr,
171			   pmd_t orig, pmd_t pmd)
172{
173	if (mm == &init_mm)
174		return;
175
176	if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {
177		/*
178		 * Note that this routine only sets pmds for THP pages.
179		 * Hugetlb pages are handled elsewhere.  We need to check
180		 * for huge zero page.  Huge zero pages are like hugetlb
181		 * pages in that there is no RSS, but there is the need
182		 * for TSB entries.  So, huge zero page counts go into
183		 * hugetlb_pte_count.
184		 */
185		if (pmd_val(pmd) & _PAGE_PMD_HUGE) {
186			if (is_huge_zero_page(pmd_page(pmd)))
187				mm->context.hugetlb_pte_count++;
188			else
189				mm->context.thp_pte_count++;
190		} else {
191			if (is_huge_zero_page(pmd_page(orig)))
192				mm->context.hugetlb_pte_count--;
193			else
194				mm->context.thp_pte_count--;
195		}
196
197		/* Do not try to allocate the TSB hash table if we
198		 * don't have one already.  We have various locks held
199		 * and thus we'll end up doing a GFP_KERNEL allocation
200		 * in an atomic context.
201		 *
202		 * Instead, we let the first TLB miss on a hugepage
203		 * take care of this.
204		 */
205	}
206
207	if (!pmd_none(orig)) {
208		addr &= HPAGE_MASK;
209		if (pmd_trans_huge(orig)) {
210			pte_t orig_pte = __pte(pmd_val(orig));
211			bool exec = pte_exec(orig_pte);
212
213			tlb_batch_add_one(mm, addr, exec, REAL_HPAGE_SHIFT);
214			tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec,
215					  REAL_HPAGE_SHIFT);
216		} else {
217			tlb_batch_pmd_scan(mm, addr, orig);
218		}
219	}
220}
221
222void set_pmd_at(struct mm_struct *mm, unsigned long addr,
223		pmd_t *pmdp, pmd_t pmd)
224{
225	pmd_t orig = *pmdp;
226
227	*pmdp = pmd;
228	__set_pmd_acct(mm, addr, orig, pmd);
229}
230
231static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
232		unsigned long address, pmd_t *pmdp, pmd_t pmd)
233{
234	pmd_t old;
235
236	do {
237		old = *pmdp;
238	} while (cmpxchg64(&pmdp->pmd, old.pmd, pmd.pmd) != old.pmd);
239	__set_pmd_acct(vma->vm_mm, address, old, pmd);
240
241	return old;
242}
243
244/*
245 * This routine is only called when splitting a THP
246 */
247pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
248		     pmd_t *pmdp)
249{
250	pmd_t old, entry;
251
252	entry = __pmd(pmd_val(*pmdp) & ~_PAGE_VALID);
253	old = pmdp_establish(vma, address, pmdp, entry);
254	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
255
256	/*
257	 * set_pmd_at() will not be called in a way to decrement
258	 * thp_pte_count when splitting a THP, so do it now.
259	 * Sanity check pmd before doing the actual decrement.
260	 */
261	if ((pmd_val(entry) & _PAGE_PMD_HUGE) &&
262	    !is_huge_zero_page(pmd_page(entry)))
263		(vma->vm_mm)->context.thp_pte_count--;
264
265	return old;
266}
267
268void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
269				pgtable_t pgtable)
270{
271	struct list_head *lh = (struct list_head *) pgtable;
272
273	assert_spin_locked(&mm->page_table_lock);
274
275	/* FIFO */
276	if (!pmd_huge_pte(mm, pmdp))
277		INIT_LIST_HEAD(lh);
278	else
279		list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
280	pmd_huge_pte(mm, pmdp) = pgtable;
281}
282
283pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
284{
285	struct list_head *lh;
286	pgtable_t pgtable;
287
288	assert_spin_locked(&mm->page_table_lock);
289
290	/* FIFO */
291	pgtable = pmd_huge_pte(mm, pmdp);
292	lh = (struct list_head *) pgtable;
293	if (list_empty(lh))
294		pmd_huge_pte(mm, pmdp) = NULL;
295	else {
296		pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
297		list_del(lh);
298	}
299	pte_val(pgtable[0]) = 0;
300	pte_val(pgtable[1]) = 0;
301
302	return pgtable;
303}
304#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
305