10186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala/* 20186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * This file contains common routines for dealing with free of page tables 38d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * Along with common page table handling code 40186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * 50186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Derived from arch/powerpc/mm/tlb_64.c: 60186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 70186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * 80186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) 90186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * and Cort Dougan (PReP) (cort@cs.nmt.edu) 100186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Copyright (C) 1996 Paul Mackerras 110186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * 120186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Derived from "arch/i386/mm/init.c" 130186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 140186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * 150186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Dave Engebretsen <engebret@us.ibm.com> 160186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * Rework for PPC64 port. 170186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * 180186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * This program is free software; you can redistribute it and/or 190186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * modify it under the terms of the GNU General Public License 200186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * as published by the Free Software Foundation; either version 210186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala * 2 of the License, or (at your option) any later version. 220186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala */ 230186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala 240186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <linux/kernel.h> 255a0e3ad6af8660be21ca98a971cd00f331318c05Tejun Heo#include <linux/gfp.h> 260186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <linux/mm.h> 270186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <linux/percpu.h> 280186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <linux/hardirq.h> 2941151e77a4d96ea138cede6d84c955aa4769ce74Becky Bruce#include <linux/hugetlb.h> 300186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <asm/pgalloc.h> 310186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <asm/tlbflush.h> 320186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala#include <asm/tlb.h> 330186f47e703fb7aa14b54459d642ef5374b3a685Kumar Gala 348d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidtstatic inline int is_exec_fault(void) 358d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 368d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt return current->thread.regs && TRAP(current->thread.regs) == 0x400; 378d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 388d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 398d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt/* We only try to do i/d cache coherency on stuff that looks like 408d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * reasonably "normal" PTEs. We currently require a PTE to be present 41ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * and we avoid _PAGE_SPECIAL and _PAGE_NO_CACHE. We also only do that 42ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * on userspace PTEs 438d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt */ 448d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidtstatic inline int pte_looks_normal(pte_t pte) 458d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 468d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt return (pte_val(pte) & 47ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt (_PAGE_PRESENT | _PAGE_SPECIAL | _PAGE_NO_CACHE | _PAGE_USER)) == 48ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt (_PAGE_PRESENT | _PAGE_USER); 498d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 508d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 51e51df2c170efaeadce4d416e1825b0830de0a795Anton Blanchardstatic struct page *maybe_pte_to_page(pte_t pte) 52ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt{ 53ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt unsigned long pfn = pte_pfn(pte); 54ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt struct page *page; 55ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 56ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (unlikely(!pfn_valid(pfn))) 57ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return NULL; 58ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt page = pfn_to_page(pfn); 59ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (PageReserved(page)) 60ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return NULL; 61ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return page; 62ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt} 63ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 64ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt#if defined(CONFIG_PPC_STD_MMU) || _PAGE_EXEC == 0 65ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 668d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt/* Server-style MMU handles coherency when hashing if HW exec permission 67ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * is supposed per page (currently 64-bit only). If not, then, we always 68ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * flush the cache for valid PTEs in set_pte. Embedded CPU without HW exec 69ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * support falls into the same category. 708d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt */ 71ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 7279df1b374ba681f1322a0efd9a88bb85f1462796LEROY Christophestatic pte_t set_pte_filter(pte_t pte) 738d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 74ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS); 75ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (pte_looks_normal(pte) && !(cpu_has_feature(CPU_FTR_COHERENT_ICACHE) || 76ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt cpu_has_feature(CPU_FTR_NOEXECUTE))) { 77ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt struct page *pg = maybe_pte_to_page(pte); 78ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (!pg) 79ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 80ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (!test_bit(PG_arch_1, &pg->flags)) { 81ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt flush_dcache_icache_page(pg); 82ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt set_bit(PG_arch_1, &pg->flags); 83ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt } 84ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt } 85ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 868d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 87ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 88ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidtstatic pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, 89ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt int dirty) 908d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 91ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 928d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 93ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 94ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt#else /* defined(CONFIG_PPC_STD_MMU) || _PAGE_EXEC == 0 */ 95ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 96ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt/* Embedded type MMU with HW exec support. This is a bit more complicated 97ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so 98ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * instead we "filter out" the exec permission for non clean pages. 998d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt */ 10079df1b374ba681f1322a0efd9a88bb85f1462796LEROY Christophestatic pte_t set_pte_filter(pte_t pte) 1018d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 102ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt struct page *pg; 103ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 104ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* No exec permission in the first place, move on */ 105ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (!(pte_val(pte) & _PAGE_EXEC) || !pte_looks_normal(pte)) 106ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 107ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 108ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* If you set _PAGE_EXEC on weird pages you're on your own */ 109ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt pg = maybe_pte_to_page(pte); 110ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (unlikely(!pg)) 111ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 112ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 113ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* If the page clean, we move on */ 114ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (test_bit(PG_arch_1, &pg->flags)) 115ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 116ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 117ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* If it's an exec fault, we flush the cache and make it clean */ 118ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (is_exec_fault()) { 119ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt flush_dcache_icache_page(pg); 120ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt set_bit(PG_arch_1, &pg->flags); 121ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 122ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt } 123ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 124ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* Else, we filter out _PAGE_EXEC */ 125ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return __pte(pte_val(pte) & ~_PAGE_EXEC); 1268d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 127ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 128ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidtstatic pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, 129ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt int dirty) 130ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt{ 131ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt struct page *pg; 132ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 133ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* So here, we only care about exec faults, as we use them 134ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * to recover lost _PAGE_EXEC and perform I$/D$ coherency 135ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * if necessary. Also if _PAGE_EXEC is already set, same deal, 136ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * we just bail out 137ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt */ 138ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (dirty || (pte_val(pte) & _PAGE_EXEC) || !is_exec_fault()) 139ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 140ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 141ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt#ifdef CONFIG_DEBUG_VM 142ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* So this is an exec fault, _PAGE_EXEC is not set. If it was 143ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * an error we would have bailed out earlier in do_page_fault() 144ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt * but let's make sure of it 145ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt */ 146ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (WARN_ON(!(vma->vm_flags & VM_EXEC))) 147ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return pte; 148ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt#endif /* CONFIG_DEBUG_VM */ 149ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 150ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* If you set _PAGE_EXEC on weird pages you're on your own */ 151ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt pg = maybe_pte_to_page(pte); 152ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (unlikely(!pg)) 153ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt goto bail; 154ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 155ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* If the page is already clean, we move on */ 156ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt if (test_bit(PG_arch_1, &pg->flags)) 157ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt goto bail; 158ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 159ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt /* Clean the page and set PG_arch_1 */ 160ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt flush_dcache_icache_page(pg); 161ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt set_bit(PG_arch_1, &pg->flags); 162ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 163ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt bail: 164ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt return __pte(pte_val(pte) | _PAGE_EXEC); 165ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt} 166ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt 167ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt#endif /* !(defined(CONFIG_PPC_STD_MMU) || _PAGE_EXEC == 0) */ 1688d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 1698d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt/* 1708d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * set_pte stores a linux PTE into the linux page table. 1718d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt */ 172ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidtvoid set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, 173ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt pte_t pte) 1748d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 1758d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt#ifdef CONFIG_DEBUG_VM 1768937ba48dcf62b5cdf7abb93652914af16756f50Aneesh Kumar K.V WARN_ON(pte_val(*ptep) & _PAGE_PRESENT); 1778d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt#endif 1788d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt /* Note: mm->context.id might not yet have been assigned as 1798d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * this context might not have been activated yet when this 1808d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * is called. 1818d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt */ 18279df1b374ba681f1322a0efd9a88bb85f1462796LEROY Christophe pte = set_pte_filter(pte); 1838d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 1848d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt /* Perform the setting of the PTE */ 1858d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt __set_pte_at(mm, addr, ptep, pte, 0); 1868d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 1878d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 1888d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt/* 1898d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * This is called when relaxing access to a PTE. It's also called in the page 1908d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * fault path when we don't hit any of the major fault cases, ie, a minor 1918d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have 1928d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * handled those two for us, we additionally deal with missing execute 1938d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt * permission here on some processors 1948d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt */ 1958d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidtint ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address, 1968d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pte_t *ptep, pte_t entry, int dirty) 1978d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 1988d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt int changed; 199ea3cc330ac0cd521ff07c7cd432a1848c19a7e92Benjamin Herrenschmidt entry = set_access_flags_filter(entry, vma, dirty); 2008d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt changed = !pte_same(*(ptep), entry); 2018d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt if (changed) { 20241151e77a4d96ea138cede6d84c955aa4769ce74Becky Bruce if (!is_vm_hugetlb_page(vma)) 203af3e4aca47d2e05a545a5e10ba5c7193e0b665e0Mel Gorman assert_pte_locked(vma->vm_mm, address); 2048d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt __ptep_set_access_flags(ptep, entry); 2058d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt flush_tlb_page_nohash(vma, address); 2068d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt } 2078d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt return changed; 2088d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 2098d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 2108d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt#ifdef CONFIG_DEBUG_VM 2118d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidtvoid assert_pte_locked(struct mm_struct *mm, unsigned long addr) 2128d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt{ 2138d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pgd_t *pgd; 2148d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pud_t *pud; 2158d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pmd_t *pmd; 2168d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 2178d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt if (mm == &init_mm) 2188d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt return; 2198d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pgd = mm->pgd + pgd_index(addr); 2208d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt BUG_ON(pgd_none(*pgd)); 2218d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pud = pud_offset(pgd, addr); 2228d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt BUG_ON(pud_none(*pud)); 2238d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt pmd = pmd_offset(pud, addr); 224a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V /* 225a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V * khugepaged to collapse normal pages to hugepage, first set 226a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V * pmd to none to force page fault/gup to take mmap_sem. After 227a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V * pmd is set to none, we do a pte_clear which does this assertion 228a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V * so if we find pmd none, return. 229a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V */ 230a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V if (pmd_none(*pmd)) 231a00e7bea0dde6a44b9bbe84f30b731d9ec73858bAneesh Kumar K.V return; 2328d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt BUG_ON(!pmd_present(*pmd)); 233797a747a82e23530ee45d2927bf84f3571c1acb2Kumar Gala assert_spin_locked(pte_lockptr(mm, pmd)); 2348d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt} 2358d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt#endif /* CONFIG_DEBUG_VM */ 2368d30c14cab30d405a05f2aaceda1e9ad57800f36Benjamin Herrenschmidt 237