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Diffstat (limited to 'arch/powerpc/mm/tlb_hash64.c')
| -rw-r--r-- | arch/powerpc/mm/tlb_hash64.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c new file mode 100644 index 000000000..87d71dd25 --- /dev/null +++ b/arch/powerpc/mm/tlb_hash64.c @@ -0,0 +1,259 @@ +/* + * 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 <engebret@us.ibm.com> + * 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 <linux/kernel.h> +#include <linux/mm.h> +#include <linux/percpu.h> +#include <linux/hardirq.h> +#include <asm/pgalloc.h> +#include <asm/tlbflush.h> +#include <asm/tlb.h> +#include <asm/bug.h> +#include <asm/pte-walk.h> + + +#include <trace/events/thp.h> + +DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch); + +/* + * 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. + */ +void hpte_need_flush(struct mm_struct *mm, unsigned long addr, + pte_t *ptep, unsigned long pte, int huge) +{ + unsigned long vpn; + struct ppc64_tlb_batch *batch = &get_cpu_var(ppc64_tlb_batch); + unsigned long vsid; + unsigned int psize; + int ssize; + real_pte_t rpte; + int i, offset; + + i = batch->index; + + /* 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 = get_slice_psize(mm, addr); + /* Mask the address for the correct page size */ + addr &= ~((1UL << mmu_psize_defs[psize].shift) - 1); + if (unlikely(psize == MMU_PAGE_16G)) + offset = PTRS_PER_PUD; + else + offset = PTRS_PER_PMD; +#else + BUG(); + psize = pte_pagesize_index(mm, addr, pte); /* shutup gcc */ +#endif + } else { + psize = pte_pagesize_index(mm, addr, pte); + /* Mask the address for the standard page size. If we + * have a 64k page kernel, but the hardware does not + * support 64k pages, this might be different from the + * hardware page size encoded in the slice table. */ + addr &= PAGE_MASK; + offset = PTRS_PER_PTE; + } + + + /* Build full vaddr */ + if (!is_kernel_addr(addr)) { + ssize = user_segment_size(addr); + vsid = get_user_vsid(&mm->context, addr, ssize); + } else { + vsid = get_kernel_vsid(addr, mmu_kernel_ssize); + ssize = mmu_kernel_ssize; + } + WARN_ON(vsid == 0); + vpn = hpt_vpn(addr, vsid, ssize); + rpte = __real_pte(__pte(pte), ptep, offset); + + /* + * Check if we have an active batch on this CPU. If not, just + * flush now and return. + */ + if (!batch->active) { + flush_hash_page(vpn, rpte, psize, ssize, mm_is_thread_local(mm)); + put_cpu_var(ppc64_tlb_batch); + 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->vpn[i] = vpn; + batch->index = ++i; + if (i >= PPC64_TLB_BATCH_NR) + __flush_tlb_pending(batch); + put_cpu_var(ppc64_tlb_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) +{ + int i, local; + + i = batch->index; + local = mm_is_thread_local(batch->mm); + if (i == 1) + flush_hash_page(batch->vpn[0], batch->pte[0], + batch->psize, batch->ssize, local); + else + flush_hash_range(i, local); + batch->index = 0; +} + +void hash__tlb_flush(struct mmu_gather *tlb) +{ + struct ppc64_tlb_batch *tlbbatch = &get_cpu_var(ppc64_tlb_batch); + + /* If there's a TLB batch pending, then we must flush it because the + * pages are going to be freed and we really don't want to have a CPU + * access a freed page because it has a stale TLB + */ + if (tlbbatch->index) + __flush_tlb_pending(tlbbatch); + + put_cpu_var(ppc64_tlb_batch); +} + +/** + * __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 is implemented for small size rather + * than speed. + */ +void __flush_hash_table_range(struct mm_struct *mm, unsigned long start, + unsigned long end) +{ + bool is_thp; + int hugepage_shift; + 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_current_mm_pte(mm->pgd, start, &is_thp, + &hugepage_shift); + unsigned long pte; + + if (ptep == NULL) + continue; + pte = pte_val(*ptep); + if (is_thp) + trace_hugepage_invalidate(start, pte); + if (!(pte & H_PAGE_HASHPTE)) + continue; + if (unlikely(is_thp)) + hpte_do_hugepage_flush(mm, start, (pmd_t *)ptep, pte); + else + hpte_need_flush(mm, start, ptep, pte, hugepage_shift); + } + arch_leave_lazy_mmu_mode(); + local_irq_restore(flags); +} + +void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr) +{ + pte_t *pte; + pte_t *start_pte; + unsigned long flags; + + addr = _ALIGN_DOWN(addr, PMD_SIZE); + /* 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(); + start_pte = pte_offset_map(pmd, addr); + for (pte = start_pte; pte < start_pte + PTRS_PER_PTE; pte++) { + unsigned long pteval = pte_val(*pte); + if (pteval & H_PAGE_HASHPTE) + hpte_need_flush(mm, addr, pte, pteval, 0); + addr += PAGE_SIZE; + } + arch_leave_lazy_mmu_mode(); + local_irq_restore(flags); +} |