1 /*
2 * This file contains the routines for flushing entries from the
3 * TLB and MMU hash table.
4 *
5 * Derived from arch/ppc64/mm/init.c:
6 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
7 *
8 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
9 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
10 * Copyright (C) 1996 Paul Mackerras
11 *
12 * Derived from "arch/i386/mm/init.c"
13 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
14 *
15 * Dave Engebretsen <engebret@us.ibm.com>
16 * Rework for PPC64 port.
17 *
18 * This program is free software; you can redistribute it and/or
19 * modify it under the terms of the GNU General Public License
20 * as published by the Free Software Foundation; either version
21 * 2 of the License, or (at your option) any later version.
22 */
23
24 #include <linux/kernel.h>
25 #include <linux/mm.h>
26 #include <linux/percpu.h>
27 #include <linux/hardirq.h>
28 #include <asm/pgalloc.h>
29 #include <asm/tlbflush.h>
30 #include <asm/tlb.h>
31 #include <asm/bug.h>
32 #include <asm/pte-walk.h>
33
34
35 #include <trace/events/thp.h>
36
37 DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
38
39 /*
40 * A linux PTE was changed and the corresponding hash table entry
41 * neesd to be flushed. This function will either perform the flush
42 * immediately or will batch it up if the current CPU has an active
43 * batch on it.
44 */
hpte_need_flush(struct mm_struct * mm,unsigned long addr,pte_t * ptep,unsigned long pte,int huge)45 void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
46 pte_t *ptep, unsigned long pte, int huge)
47 {
48 unsigned long vpn;
49 struct ppc64_tlb_batch *batch = &get_cpu_var(ppc64_tlb_batch);
50 unsigned long vsid;
51 unsigned int psize;
52 int ssize;
53 real_pte_t rpte;
54 int i, offset;
55
56 i = batch->index;
57
58 /* Get page size (maybe move back to caller).
59 *
60 * NOTE: when using special 64K mappings in 4K environment like
61 * for SPEs, we obtain the page size from the slice, which thus
62 * must still exist (and thus the VMA not reused) at the time
63 * of this call
64 */
65 if (huge) {
66 #ifdef CONFIG_HUGETLB_PAGE
67 psize = get_slice_psize(mm, addr);
68 /* Mask the address for the correct page size */
69 addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1);
70 if (unlikely(psize == MMU_PAGE_16G))
71 offset = PTRS_PER_PUD;
72 else
73 offset = PTRS_PER_PMD;
74 #else
75 BUG();
76 psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */
77 #endif
78 } else {
79 psize = pte_pagesize_index(mm, addr, pte);
80 /* Mask the address for the standard page size. If we
81 * have a 64k page kernel, but the hardware does not
82 * support 64k pages, this might be different from the
83 * hardware page size encoded in the slice table. */
84 addr &= PAGE_MASK;
85 offset = PTRS_PER_PTE;
86 }
87
88
89 /* Build full vaddr */
90 if (!is_kernel_addr(addr)) {
91 ssize = user_segment_size(addr);
92 vsid = get_user_vsid(&mm->context, addr, ssize);
93 } else {
94 vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
95 ssize = mmu_kernel_ssize;
96 }
97 WARN_ON(vsid == 0);
98 vpn = hpt_vpn(addr, vsid, ssize);
99 rpte = __real_pte(__pte(pte), ptep, offset);
100
101 /*
102 * Check if we have an active batch on this CPU. If not, just
103 * flush now and return.
104 */
105 if (!batch->active) {
106 flush_hash_page(vpn, rpte, psize, ssize, mm_is_thread_local(mm));
107 put_cpu_var(ppc64_tlb_batch);
108 return;
109 }
110
111 /*
112 * This can happen when we are in the middle of a TLB batch and
113 * we encounter memory pressure (eg copy_page_range when it tries
114 * to allocate a new pte). If we have to reclaim memory and end
115 * up scanning and resetting referenced bits then our batch context
116 * will change mid stream.
117 *
118 * We also need to ensure only one page size is present in a given
119 * batch
120 */
121 if (i != 0 && (mm != batch->mm || batch->psize != psize ||
122 batch->ssize != ssize)) {
123 __flush_tlb_pending(batch);
124 i = 0;
125 }
126 if (i == 0) {
127 batch->mm = mm;
128 batch->psize = psize;
129 batch->ssize = ssize;
130 }
131 batch->pte[i] = rpte;
132 batch->vpn[i] = vpn;
133 batch->index = ++i;
134 if (i >= PPC64_TLB_BATCH_NR)
135 __flush_tlb_pending(batch);
136 put_cpu_var(ppc64_tlb_batch);
137 }
138
139 /*
140 * This function is called when terminating an mmu batch or when a batch
141 * is full. It will perform the flush of all the entries currently stored
142 * in a batch.
143 *
144 * Must be called from within some kind of spinlock/non-preempt region...
145 */
__flush_tlb_pending(struct ppc64_tlb_batch * batch)146 void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
147 {
148 int i, local;
149
150 i = batch->index;
151 local = mm_is_thread_local(batch->mm);
152 if (i == 1)
153 flush_hash_page(batch->vpn[0], batch->pte[0],
154 batch->psize, batch->ssize, local);
155 else
156 flush_hash_range(i, local);
157 batch->index = 0;
158 }
159
hash__tlb_flush(struct mmu_gather * tlb)160 void hash__tlb_flush(struct mmu_gather *tlb)
161 {
162 struct ppc64_tlb_batch *tlbbatch = &get_cpu_var(ppc64_tlb_batch);
163
164 /* If there's a TLB batch pending, then we must flush it because the
165 * pages are going to be freed and we really don't want to have a CPU
166 * access a freed page because it has a stale TLB
167 */
168 if (tlbbatch->index)
169 __flush_tlb_pending(tlbbatch);
170
171 put_cpu_var(ppc64_tlb_batch);
172 }
173
174 /**
175 * __flush_hash_table_range - Flush all HPTEs for a given address range
176 * from the hash table (and the TLB). But keeps
177 * the linux PTEs intact.
178 *
179 * @mm : mm_struct of the target address space (generally init_mm)
180 * @start : starting address
181 * @end : ending address (not included in the flush)
182 *
183 * This function is mostly to be used by some IO hotplug code in order
184 * to remove all hash entries from a given address range used to map IO
185 * space on a removed PCI-PCI bidge without tearing down the full mapping
186 * since 64K pages may overlap with other bridges when using 64K pages
187 * with 4K HW pages on IO space.
188 *
189 * Because of that usage pattern, it is implemented for small size rather
190 * than speed.
191 */
__flush_hash_table_range(struct mm_struct * mm,unsigned long start,unsigned long end)192 void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
193 unsigned long end)
194 {
195 bool is_thp;
196 int hugepage_shift;
197 unsigned long flags;
198
199 start = _ALIGN_DOWN(start, PAGE_SIZE);
200 end = _ALIGN_UP(end, PAGE_SIZE);
201
202 BUG_ON(!mm->pgd);
203
204 /* Note: Normally, we should only ever use a batch within a
205 * PTE locked section. This violates the rule, but will work
206 * since we don't actually modify the PTEs, we just flush the
207 * hash while leaving the PTEs intact (including their reference
208 * to being hashed). This is not the most performance oriented
209 * way to do things but is fine for our needs here.
210 */
211 local_irq_save(flags);
212 arch_enter_lazy_mmu_mode();
213 for (; start < end; start += PAGE_SIZE) {
214 pte_t *ptep = find_current_mm_pte(mm->pgd, start, &is_thp,
215 &hugepage_shift);
216 unsigned long pte;
217
218 if (ptep == NULL)
219 continue;
220 pte = pte_val(*ptep);
221 if (is_thp)
222 trace_hugepage_invalidate(start, pte);
223 if (!(pte & H_PAGE_HASHPTE))
224 continue;
225 if (unlikely(is_thp))
226 hpte_do_hugepage_flush(mm, start, (pmd_t *)ptep, pte);
227 else
228 hpte_need_flush(mm, start, ptep, pte, hugepage_shift);
229 }
230 arch_leave_lazy_mmu_mode();
231 local_irq_restore(flags);
232 }
233
flush_tlb_pmd_range(struct mm_struct * mm,pmd_t * pmd,unsigned long addr)234 void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr)
235 {
236 pte_t *pte;
237 pte_t *start_pte;
238 unsigned long flags;
239
240 addr = _ALIGN_DOWN(addr, PMD_SIZE);
241 /* Note: Normally, we should only ever use a batch within a
242 * PTE locked section. This violates the rule, but will work
243 * since we don't actually modify the PTEs, we just flush the
244 * hash while leaving the PTEs intact (including their reference
245 * to being hashed). This is not the most performance oriented
246 * way to do things but is fine for our needs here.
247 */
248 local_irq_save(flags);
249 arch_enter_lazy_mmu_mode();
250 start_pte = pte_offset_map(pmd, addr);
251 for (pte = start_pte; pte < start_pte + PTRS_PER_PTE; pte++) {
252 unsigned long pteval = pte_val(*pte);
253 if (pteval & H_PAGE_HASHPTE)
254 hpte_need_flush(mm, addr, pte, pteval, 0);
255 addr += PAGE_SIZE;
256 }
257 arch_leave_lazy_mmu_mode();
258 local_irq_restore(flags);
259 }
260
