/* * This file contains the routines for flushing entries from the * TLB and MMU hash table. * * Derived from arch/ppc64/mm/init.c: * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) * * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) * and Cort Dougan (PReP) (cort@cs.nmt.edu) * Copyright (C) 1996 Paul Mackerras * * Derived from "arch/i386/mm/init.c" * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * * Dave Engebretsen * Rework for PPC64 port. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch); /* This is declared as we are using the more or less generic * include/asm-powerpc/tlb.h file -- tgall */ DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur); unsigned long pte_freelist_forced_free; struct pte_freelist_batch { struct rcu_head rcu; unsigned int index; pgtable_free_t tables[0]; }; DEFINE_PER_CPU(struct pte_freelist_batch *, pte_freelist_cur); unsigned long pte_freelist_forced_free; #define PTE_FREELIST_SIZE \ ((PAGE_SIZE - sizeof(struct pte_freelist_batch)) \ / sizeof(pgtable_free_t)) static void pte_free_smp_sync(void *arg) { /* Do nothing, just ensure we sync with all CPUs */ } /* This is only called when we are critically out of memory * (and fail to get a page in pte_free_tlb). */ static void pgtable_free_now(pgtable_free_t pgf) { pte_freelist_forced_free++; smp_call_function(pte_free_smp_sync, NULL, 0, 1); pgtable_free(pgf); } static void pte_free_rcu_callback(struct rcu_head *head) { struct pte_freelist_batch *batch = container_of(head, struct pte_freelist_batch, rcu); unsigned int i; for (i = 0; i < batch->index; i++) pgtable_free(batch->tables[i]); free_page((unsigned long)batch); } static void pte_free_submit(struct pte_freelist_batch *batch) { INIT_RCU_HEAD(&batch->rcu); call_rcu(&batch->rcu, pte_free_rcu_callback); } void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf) { /* This is safe since tlb_gather_mmu has disabled preemption */ cpumask_t local_cpumask = cpumask_of_cpu(smp_processor_id()); struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur); if (atomic_read(&tlb->mm->mm_users) < 2 || cpus_equal(tlb->mm->cpu_vm_mask, local_cpumask)) { pgtable_free(pgf); return; } if (*batchp == NULL) { *batchp = (struct pte_freelist_batch *)__get_free_page(GFP_ATOMIC); if (*batchp == NULL) { pgtable_free_now(pgf); return; } (*batchp)->index = 0; } (*batchp)->tables[(*batchp)->index++] = pgf; if ((*batchp)->index == PTE_FREELIST_SIZE) { pte_free_submit(*batchp); *batchp = NULL; } } /* * A linux PTE was changed and the corresponding hash table entry * neesd to be flushed. This function will either perform the flush * immediately or will batch it up if the current CPU has an active * batch on it. * * Must be called from within some kind of spinlock/non-preempt region... */ void hpte_need_flush(struct mm_struct *mm, unsigned long addr, pte_t *ptep, unsigned long pte, int huge) { struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch); unsigned long vsid, vaddr; unsigned int psize; int ssize; real_pte_t rpte; int i; i = batch->index; /* We mask the address for the base page size. Huge pages will * have applied their own masking already */ addr &= PAGE_MASK; /* Get page size (maybe move back to caller). * * NOTE: when using special 64K mappings in 4K environment like * for SPEs, we obtain the page size from the slice, which thus * must still exist (and thus the VMA not reused) at the time * of this call */ if (huge) { #ifdef CONFIG_HUGETLB_PAGE psize = mmu_huge_psize; #else BUG(); psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */ #endif } else psize = pte_pagesize_index(mm, addr, pte); /* Build full vaddr */ if (!is_kernel_addr(addr)) { ssize = user_segment_size(addr); vsid = get_vsid(mm->context.id, addr, ssize); WARN_ON(vsid == 0); } else { vsid = get_kernel_vsid(addr, mmu_kernel_ssize); ssize = mmu_kernel_ssize; } vaddr = hpt_va(addr, vsid, ssize); rpte = __real_pte(__pte(pte), ptep); /* * Check if we have an active batch on this CPU. If not, just * flush now and return. For now, we don global invalidates * in that case, might be worth testing the mm cpu mask though * and decide to use local invalidates instead... */ if (!batch->active) { flush_hash_page(vaddr, rpte, psize, ssize, 0); return; } /* * This can happen when we are in the middle of a TLB batch and * we encounter memory pressure (eg copy_page_range when it tries * to allocate a new pte). If we have to reclaim memory and end * up scanning and resetting referenced bits then our batch context * will change mid stream. * * We also need to ensure only one page size is present in a given * batch */ if (i != 0 && (mm != batch->mm || batch->psize != psize || batch->ssize != ssize)) { __flush_tlb_pending(batch); i = 0; } if (i == 0) { batch->mm = mm; batch->psize = psize; batch->ssize = ssize; } batch->pte[i] = rpte; batch->vaddr[i] = vaddr; batch->index = ++i; if (i >= PPC64_TLB_BATCH_NR) __flush_tlb_pending(batch); } /* * This function is called when terminating an mmu batch or when a batch * is full. It will perform the flush of all the entries currently stored * in a batch. * * Must be called from within some kind of spinlock/non-preempt region... */ void __flush_tlb_pending(struct ppc64_tlb_batch *batch) { cpumask_t tmp; int i, local = 0; i = batch->index; tmp = cpumask_of_cpu(smp_processor_id()); if (cpus_equal(batch->mm->cpu_vm_mask, tmp)) local = 1; if (i == 1) flush_hash_page(batch->vaddr[0], batch->pte[0], batch->psize, batch->ssize, local); else flush_hash_range(i, local); batch->index = 0; } void pte_free_finish(void) { /* This is safe since tlb_gather_mmu has disabled preemption */ struct pte_freelist_batch **batchp = &__get_cpu_var(pte_freelist_cur); if (*batchp == NULL) return; pte_free_submit(*batchp); *batchp = NULL; } /** * __flush_hash_table_range - Flush all HPTEs for a given address range * from the hash table (and the TLB). But keeps * the linux PTEs intact. * * @mm : mm_struct of the target address space (generally init_mm) * @start : starting address * @end : ending address (not included in the flush) * * This function is mostly to be used by some IO hotplug code in order * to remove all hash entries from a given address range used to map IO * space on a removed PCI-PCI bidge without tearing down the full mapping * since 64K pages may overlap with other bridges when using 64K pages * with 4K HW pages on IO space. * * Because of that usage pattern, it's only available with CONFIG_HOTPLUG * and is implemented for small size rather than speed. */ #ifdef CONFIG_HOTPLUG void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, unsigned long end) { unsigned long flags; start = _ALIGN_DOWN(start, PAGE_SIZE); end = _ALIGN_UP(end, PAGE_SIZE); BUG_ON(!mm->pgd); /* Note: Normally, we should only ever use a batch within a * PTE locked section. This violates the rule, but will work * since we don't actually modify the PTEs, we just flush the * hash while leaving the PTEs intact (including their reference * to being hashed). This is not the most performance oriented * way to do things but is fine for our needs here. */ local_irq_save(flags); arch_enter_lazy_mmu_mode(); for (; start < end; start += PAGE_SIZE) { pte_t *ptep = find_linux_pte(mm->pgd, start); unsigned long pte; if (ptep == NULL) continue; pte = pte_val(*ptep); if (!(pte & _PAGE_HASHPTE)) continue; hpte_need_flush(mm, start, ptep, pte, 0); } arch_leave_lazy_mmu_mode(); local_irq_restore(flags); } #endif /* CONFIG_HOTPLUG */