1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * This file contains the routines for flushing entries from the 4 * TLB and MMU hash table. 5 * 6 * Derived from arch/ppc64/mm/init.c: 7 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 8 * 9 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 10 * and Cort Dougan (PReP) (cort@cs.nmt.edu) 11 * Copyright (C) 1996 Paul Mackerras 12 * 13 * Derived from "arch/i386/mm/init.c" 14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 15 * 16 * Dave Engebretsen <engebret@us.ibm.com> 17 * Rework for PPC64 port. 18 */ 19 20 #include <linux/kernel.h> 21 #include <linux/mm.h> 22 #include <linux/percpu.h> 23 #include <linux/hardirq.h> 24 #include <asm/tlbflush.h> 25 #include <asm/tlb.h> 26 #include <asm/bug.h> 27 #include <asm/pte-walk.h> 28 #include <kunit/visibility.h> 29 30 #include <trace/events/thp.h> 31 32 DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch); 33 EXPORT_SYMBOL_IF_KUNIT(ppc64_tlb_batch); 34 35 /* 36 * A linux PTE was changed and the corresponding hash table entry 37 * neesd to be flushed. This function will either perform the flush 38 * immediately or will batch it up if the current CPU has an active 39 * batch on it. 40 */ 41 void hpte_need_flush(struct mm_struct *mm, unsigned long addr, 42 pte_t *ptep, unsigned long pte, int huge) 43 { 44 unsigned long vpn; 45 struct ppc64_tlb_batch *batch = &get_cpu_var(ppc64_tlb_batch); 46 unsigned long vsid; 47 unsigned int psize; 48 int ssize; 49 real_pte_t rpte; 50 int i, offset; 51 52 i = batch->index; 53 54 /* 55 * Get page size (maybe move back to caller). 56 * 57 * NOTE: when using special 64K mappings in 4K environment like 58 * for SPEs, we obtain the page size from the slice, which thus 59 * must still exist (and thus the VMA not reused) at the time 60 * of this call 61 */ 62 if (huge) { 63 #ifdef CONFIG_HUGETLB_PAGE 64 psize = get_slice_psize(mm, addr); 65 /* Mask the address for the correct page size */ 66 addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1); 67 if (unlikely(psize == MMU_PAGE_16G)) 68 offset = PTRS_PER_PUD; 69 else 70 offset = PTRS_PER_PMD; 71 #else 72 BUG(); 73 psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */ 74 #endif 75 } else { 76 psize = pte_pagesize_index(mm, addr, pte); 77 /* 78 * Mask the address for the standard page size. If we 79 * have a 64k page kernel, but the hardware does not 80 * support 64k pages, this might be different from the 81 * hardware page size encoded in the slice table. 82 */ 83 addr &= PAGE_MASK; 84 offset = PTRS_PER_PTE; 85 } 86 87 88 /* Build full vaddr */ 89 if (!is_kernel_addr(addr)) { 90 ssize = user_segment_size(addr); 91 vsid = get_user_vsid(&mm->context, addr, ssize); 92 } else { 93 vsid = get_kernel_vsid(addr, mmu_kernel_ssize); 94 ssize = mmu_kernel_ssize; 95 } 96 WARN_ON(vsid == 0); 97 vpn = hpt_vpn(addr, vsid, ssize); 98 rpte = __real_pte(__pte(pte), ptep, offset); 99 100 /* 101 * Check if we have an active batch on this CPU. If not, just 102 * flush now and return. 103 */ 104 if (!is_lazy_mmu_mode_active()) { 105 flush_hash_page(vpn, rpte, psize, ssize, mm_is_thread_local(mm)); 106 put_cpu_var(ppc64_tlb_batch); 107 return; 108 } 109 110 /* 111 * This can happen when we are in the middle of a TLB batch and 112 * we encounter memory pressure (eg copy_page_range when it tries 113 * to allocate a new pte). If we have to reclaim memory and end 114 * up scanning and resetting referenced bits then our batch context 115 * will change mid stream. 116 * 117 * We also need to ensure only one page size is present in a given 118 * batch 119 */ 120 if (i != 0 && (mm != batch->mm || batch->psize != psize || 121 batch->ssize != ssize)) { 122 __flush_tlb_pending(batch); 123 i = 0; 124 } 125 if (i == 0) { 126 batch->mm = mm; 127 batch->psize = psize; 128 batch->ssize = ssize; 129 } 130 batch->pte[i] = rpte; 131 batch->vpn[i] = vpn; 132 batch->index = ++i; 133 if (i >= PPC64_TLB_BATCH_NR) 134 __flush_tlb_pending(batch); 135 put_cpu_var(ppc64_tlb_batch); 136 } 137 138 /* 139 * This function is called when terminating an mmu batch or when a batch 140 * is full. It will perform the flush of all the entries currently stored 141 * in a batch. 142 * 143 * Must be called from within some kind of spinlock/non-preempt region... 144 */ 145 void __flush_tlb_pending(struct ppc64_tlb_batch *batch) 146 { 147 int i, local; 148 149 i = batch->index; 150 local = mm_is_thread_local(batch->mm); 151 if (i == 1) 152 flush_hash_page(batch->vpn[0], batch->pte[0], 153 batch->psize, batch->ssize, local); 154 else 155 flush_hash_range(i, local); 156 batch->index = 0; 157 } 158 EXPORT_SYMBOL_IF_KUNIT(__flush_tlb_pending); 159 160 void hash__tlb_flush(struct mmu_gather *tlb) 161 { 162 struct ppc64_tlb_batch *tlbbatch = &get_cpu_var(ppc64_tlb_batch); 163 164 /* 165 * If there's a TLB batch pending, then we must flush it because the 166 * pages are going to be freed and we really don't want to have a CPU 167 * access a freed page because it has a stale TLB 168 */ 169 if (tlbbatch->index) 170 __flush_tlb_pending(tlbbatch); 171 172 put_cpu_var(ppc64_tlb_batch); 173 } 174 175 /** 176 * __flush_hash_table_range - Flush all HPTEs for a given address range 177 * from the hash table (and the TLB). But keeps 178 * the linux PTEs intact. 179 * 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 */ 192 void __flush_hash_table_range(unsigned long start, unsigned long end) 193 { 194 int hugepage_shift; 195 unsigned long flags; 196 197 start = ALIGN_DOWN(start, PAGE_SIZE); 198 end = ALIGN(end, PAGE_SIZE); 199 200 201 /* 202 * Note: Normally, we should only ever use a batch within a 203 * PTE locked section. This violates the rule, but will work 204 * since we don't actually modify the PTEs, we just flush the 205 * hash while leaving the PTEs intact (including their reference 206 * to being hashed). This is not the most performance oriented 207 * way to do things but is fine for our needs here. 208 */ 209 local_irq_save(flags); 210 lazy_mmu_mode_enable(); 211 for (; start < end; start += PAGE_SIZE) { 212 pte_t *ptep = find_init_mm_pte(start, &hugepage_shift); 213 unsigned long pte; 214 215 if (ptep == NULL) 216 continue; 217 pte = pte_val(*ptep); 218 if (!(pte & H_PAGE_HASHPTE)) 219 continue; 220 hpte_need_flush(&init_mm, start, ptep, pte, hugepage_shift); 221 } 222 lazy_mmu_mode_disable(); 223 local_irq_restore(flags); 224 } 225 226 void flush_hash_table_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr) 227 { 228 pte_t *pte; 229 pte_t *start_pte; 230 unsigned long flags; 231 232 addr = ALIGN_DOWN(addr, PMD_SIZE); 233 /* 234 * Note: Normally, we should only ever use a batch within a 235 * PTE locked section. This violates the rule, but will work 236 * since we don't actually modify the PTEs, we just flush the 237 * hash while leaving the PTEs intact (including their reference 238 * to being hashed). This is not the most performance oriented 239 * way to do things but is fine for our needs here. 240 */ 241 local_irq_save(flags); 242 lazy_mmu_mode_enable(); 243 start_pte = pte_offset_map(pmd, addr); 244 if (!start_pte) 245 goto out; 246 for (pte = start_pte; pte < start_pte + PTRS_PER_PTE; pte++) { 247 unsigned long pteval = pte_val(*pte); 248 if (pteval & H_PAGE_HASHPTE) 249 hpte_need_flush(mm, addr, pte, pteval, 0); 250 addr += PAGE_SIZE; 251 } 252 pte_unmap(start_pte); 253 out: 254 lazy_mmu_mode_disable(); 255 local_irq_restore(flags); 256 } 257