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![Mel Gorman](/assets/img/avatar_default.png)
Convert existing users of pte_numa and friends to the new helper. Note that the kernel is broken after this patch is applied until the other page table modifiers are also altered. This patch layout is to make review easier. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Sasha Levin <sasha.levin@oracle.com> Cc: Dave Jones <davej@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Rik van Riel <riel@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
241 lines
6.7 KiB
C
241 lines
6.7 KiB
C
/*
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* This file contains common routines for dealing with free of page tables
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* Along with common page table handling code
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*
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* Derived from arch/powerpc/mm/tlb_64.c:
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* Dave Engebretsen <engebret@us.ibm.com>
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* Rework for PPC64 port.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/gfp.h>
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#include <linux/mm.h>
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#include <linux/percpu.h>
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#include <linux/hardirq.h>
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#include <linux/hugetlb.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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#include <asm/tlb.h>
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static inline int is_exec_fault(void)
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{
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return current->thread.regs && TRAP(current->thread.regs) == 0x400;
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}
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/* We only try to do i/d cache coherency on stuff that looks like
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* reasonably "normal" PTEs. We currently require a PTE to be present
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* and we avoid _PAGE_SPECIAL and _PAGE_NO_CACHE. We also only do that
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* on userspace PTEs
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*/
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static inline int pte_looks_normal(pte_t pte)
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{
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return (pte_val(pte) &
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(_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE | _PAGE_USER)) ==
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(_PAGE_PRESENT | _PAGE_USER);
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}
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static struct page *maybe_pte_to_page(pte_t pte)
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{
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unsigned long pfn = pte_pfn(pte);
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struct page *page;
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if (unlikely(!pfn_valid(pfn)))
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return NULL;
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page = pfn_to_page(pfn);
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if (PageReserved(page))
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return NULL;
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return page;
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}
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#if defined(CONFIG_PPC_STD_MMU) || _PAGE_EXEC == 0
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/* Server-style MMU handles coherency when hashing if HW exec permission
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* is supposed per page (currently 64-bit only). If not, then, we always
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* flush the cache for valid PTEs in set_pte. Embedded CPU without HW exec
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* support falls into the same category.
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*/
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static pte_t set_pte_filter(pte_t pte)
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{
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pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
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if (pte_looks_normal(pte) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE) ||
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cpu_has_feature(CPU_FTR_NOEXECUTE))) {
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struct page *pg = maybe_pte_to_page(pte);
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if (!pg)
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return pte;
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if (!test_bit(PG_arch_1, &pg->flags)) {
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flush_dcache_icache_page(pg);
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set_bit(PG_arch_1, &pg->flags);
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}
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}
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return pte;
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}
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static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
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int dirty)
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{
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return pte;
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}
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#else /* defined(CONFIG_PPC_STD_MMU) || _PAGE_EXEC == 0 */
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/* Embedded type MMU with HW exec support. This is a bit more complicated
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* as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so
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* instead we "filter out" the exec permission for non clean pages.
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*/
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static pte_t set_pte_filter(pte_t pte)
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{
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struct page *pg;
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/* No exec permission in the first place, move on */
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if (!(pte_val(pte) & _PAGE_EXEC) || !pte_looks_normal(pte))
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return pte;
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/* If you set _PAGE_EXEC on weird pages you're on your own */
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pg = maybe_pte_to_page(pte);
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if (unlikely(!pg))
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return pte;
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/* If the page clean, we move on */
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if (test_bit(PG_arch_1, &pg->flags))
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return pte;
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/* If it's an exec fault, we flush the cache and make it clean */
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if (is_exec_fault()) {
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flush_dcache_icache_page(pg);
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set_bit(PG_arch_1, &pg->flags);
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return pte;
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}
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/* Else, we filter out _PAGE_EXEC */
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return __pte(pte_val(pte) & ~_PAGE_EXEC);
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}
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static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
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int dirty)
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{
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struct page *pg;
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/* So here, we only care about exec faults, as we use them
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* to recover lost _PAGE_EXEC and perform I$/D$ coherency
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* if necessary. Also if _PAGE_EXEC is already set, same deal,
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* we just bail out
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*/
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if (dirty || (pte_val(pte) & _PAGE_EXEC) || !is_exec_fault())
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return pte;
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#ifdef CONFIG_DEBUG_VM
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/* So this is an exec fault, _PAGE_EXEC is not set. If it was
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* an error we would have bailed out earlier in do_page_fault()
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* but let's make sure of it
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*/
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if (WARN_ON(!(vma->vm_flags & VM_EXEC)))
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return pte;
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#endif /* CONFIG_DEBUG_VM */
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/* If you set _PAGE_EXEC on weird pages you're on your own */
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pg = maybe_pte_to_page(pte);
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if (unlikely(!pg))
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goto bail;
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/* If the page is already clean, we move on */
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if (test_bit(PG_arch_1, &pg->flags))
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goto bail;
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/* Clean the page and set PG_arch_1 */
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flush_dcache_icache_page(pg);
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set_bit(PG_arch_1, &pg->flags);
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bail:
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return __pte(pte_val(pte) | _PAGE_EXEC);
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}
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#endif /* !(defined(CONFIG_PPC_STD_MMU) || _PAGE_EXEC == 0) */
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/*
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* set_pte stores a linux PTE into the linux page table.
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*/
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void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
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pte_t pte)
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{
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/*
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* When handling numa faults, we already have the pte marked
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* _PAGE_PRESENT, but we can be sure that it is not in hpte.
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* Hence we can use set_pte_at for them.
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*/
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VM_WARN_ON((pte_val(*ptep) & (_PAGE_PRESENT | _PAGE_USER)) ==
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(_PAGE_PRESENT | _PAGE_USER));
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/* Note: mm->context.id might not yet have been assigned as
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* this context might not have been activated yet when this
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* is called.
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*/
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pte = set_pte_filter(pte);
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/* Perform the setting of the PTE */
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__set_pte_at(mm, addr, ptep, pte, 0);
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}
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/*
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* This is called when relaxing access to a PTE. It's also called in the page
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* fault path when we don't hit any of the major fault cases, ie, a minor
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* update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have
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* handled those two for us, we additionally deal with missing execute
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* permission here on some processors
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*/
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int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address,
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pte_t *ptep, pte_t entry, int dirty)
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{
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int changed;
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entry = set_access_flags_filter(entry, vma, dirty);
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changed = !pte_same(*(ptep), entry);
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if (changed) {
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if (!is_vm_hugetlb_page(vma))
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assert_pte_locked(vma->vm_mm, address);
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__ptep_set_access_flags(ptep, entry);
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flush_tlb_page_nohash(vma, address);
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}
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return changed;
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}
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#ifdef CONFIG_DEBUG_VM
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void assert_pte_locked(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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if (mm == &init_mm)
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return;
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pgd = mm->pgd + pgd_index(addr);
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BUG_ON(pgd_none(*pgd));
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pud = pud_offset(pgd, addr);
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BUG_ON(pud_none(*pud));
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pmd = pmd_offset(pud, addr);
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/*
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* khugepaged to collapse normal pages to hugepage, first set
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* pmd to none to force page fault/gup to take mmap_sem. After
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* pmd is set to none, we do a pte_clear which does this assertion
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* so if we find pmd none, return.
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*/
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if (pmd_none(*pmd))
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return;
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BUG_ON(!pmd_present(*pmd));
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assert_spin_locked(pte_lockptr(mm, pmd));
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}
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#endif /* CONFIG_DEBUG_VM */
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