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Diffstat (limited to 'arch/x86/mm/pgtable.c')
-rw-r--r--arch/x86/mm/pgtable.c202
1 files changed, 166 insertions, 36 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index ed34f5e3599..6fb6927f9e7 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -1,4 +1,5 @@
#include <linux/mm.h>
+#include <linux/gfp.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
@@ -6,6 +7,14 @@
#define PGALLOC_GFP GFP_KERNEL | __GFP_NOTRACK | __GFP_REPEAT | __GFP_ZERO
+#ifdef CONFIG_HIGHPTE
+#define PGALLOC_USER_GFP __GFP_HIGHMEM
+#else
+#define PGALLOC_USER_GFP 0
+#endif
+
+gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;
+
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
return (pte_t *)__get_free_page(PGALLOC_GFP);
@@ -15,16 +24,33 @@ pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
struct page *pte;
-#ifdef CONFIG_HIGHPTE
- pte = alloc_pages(PGALLOC_GFP | __GFP_HIGHMEM, 0);
-#else
- pte = alloc_pages(PGALLOC_GFP, 0);
-#endif
- if (pte)
- pgtable_page_ctor(pte);
+ pte = alloc_pages(__userpte_alloc_gfp, 0);
+ if (!pte)
+ return NULL;
+ if (!pgtable_page_ctor(pte)) {
+ __free_page(pte);
+ return NULL;
+ }
return pte;
}
+static int __init setup_userpte(char *arg)
+{
+ if (!arg)
+ return -EINVAL;
+
+ /*
+ * "userpte=nohigh" disables allocation of user pagetables in
+ * high memory.
+ */
+ if (strcmp(arg, "nohigh") == 0)
+ __userpte_alloc_gfp &= ~__GFP_HIGHMEM;
+ else
+ return -EINVAL;
+ return 0;
+}
+early_param("userpte", setup_userpte);
+
void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
{
pgtable_page_dtor(pte);
@@ -35,8 +61,17 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
#if PAGETABLE_LEVELS > 2
void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
{
+ struct page *page = virt_to_page(pmd);
paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
- tlb_remove_page(tlb, virt_to_page(pmd));
+ /*
+ * NOTE! For PAE, any changes to the top page-directory-pointer-table
+ * entries need a full cr3 reload to flush.
+ */
+#ifdef CONFIG_X86_PAE
+ tlb->need_flush_all = 1;
+#endif
+ pgtable_pmd_page_dtor(page);
+ tlb_remove_page(tlb, page);
}
#if PAGETABLE_LEVELS > 3
@@ -65,7 +100,19 @@ static inline void pgd_list_del(pgd_t *pgd)
#define UNSHARED_PTRS_PER_PGD \
(SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
-static void pgd_ctor(pgd_t *pgd)
+
+static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
+{
+ BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm));
+ virt_to_page(pgd)->index = (pgoff_t)mm;
+}
+
+struct mm_struct *pgd_page_get_mm(struct page *page)
+{
+ return (struct mm_struct *)page->index;
+}
+
+static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
{
/* If the pgd points to a shared pagetable level (either the
ptes in non-PAE, or shared PMD in PAE), then just copy the
@@ -76,27 +123,23 @@ static void pgd_ctor(pgd_t *pgd)
clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY,
swapper_pg_dir + KERNEL_PGD_BOUNDARY,
KERNEL_PGD_PTRS);
- paravirt_alloc_pmd_clone(__pa(pgd) >> PAGE_SHIFT,
- __pa(swapper_pg_dir) >> PAGE_SHIFT,
- KERNEL_PGD_BOUNDARY,
- KERNEL_PGD_PTRS);
}
/* list required to sync kernel mapping updates */
- if (!SHARED_KERNEL_PMD)
+ if (!SHARED_KERNEL_PMD) {
+ pgd_set_mm(pgd, mm);
pgd_list_add(pgd);
+ }
}
static void pgd_dtor(pgd_t *pgd)
{
- unsigned long flags; /* can be called from interrupt context */
-
if (SHARED_KERNEL_PMD)
return;
- spin_lock_irqsave(&pgd_lock, flags);
+ spin_lock(&pgd_lock);
pgd_list_del(pgd);
- spin_unlock_irqrestore(&pgd_lock, flags);
+ spin_unlock(&pgd_lock);
}
/*
@@ -107,7 +150,7 @@ static void pgd_dtor(pgd_t *pgd)
* against pageattr.c; it is the unique case in which a valid change
* of kernel pagetables can't be lazily synchronized by vmalloc faults.
* vmalloc faults work because attached pagetables are never freed.
- * -- wli
+ * -- nyc
*/
#ifdef CONFIG_X86_PAE
@@ -138,8 +181,7 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
* section 8.1: in PAE mode we explicitly have to flush the
* TLB via cr3 if the top-level pgd is changed...
*/
- if (mm == current->active_mm)
- write_cr3(read_cr3());
+ flush_tlb_mm(mm);
}
#else /* !CONFIG_X86_PAE */
@@ -153,8 +195,10 @@ static void free_pmds(pmd_t *pmds[])
int i;
for(i = 0; i < PREALLOCATED_PMDS; i++)
- if (pmds[i])
+ if (pmds[i]) {
+ pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
free_page((unsigned long)pmds[i]);
+ }
}
static int preallocate_pmds(pmd_t *pmds[])
@@ -164,8 +208,13 @@ static int preallocate_pmds(pmd_t *pmds[])
for(i = 0; i < PREALLOCATED_PMDS; i++) {
pmd_t *pmd = (pmd_t *)__get_free_page(PGALLOC_GFP);
- if (pmd == NULL)
+ if (!pmd)
+ failed = true;
+ if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
+ free_page((unsigned long)pmd);
+ pmd = NULL;
failed = true;
+ }
pmds[i] = pmd;
}
@@ -204,7 +253,6 @@ static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
{
pud_t *pud;
- unsigned long addr;
int i;
if (PREALLOCATED_PMDS == 0) /* Work around gcc-3.4.x bug */
@@ -212,8 +260,7 @@ static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
pud = pud_offset(pgd, 0);
- for (addr = i = 0; i < PREALLOCATED_PMDS;
- i++, pud++, addr += PUD_SIZE) {
+ for (i = 0; i < PREALLOCATED_PMDS; i++, pud++) {
pmd_t *pmd = pmds[i];
if (i >= KERNEL_PGD_BOUNDARY)
@@ -228,7 +275,6 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd;
pmd_t *pmds[PREALLOCATED_PMDS];
- unsigned long flags;
pgd = (pgd_t *)__get_free_page(PGALLOC_GFP);
@@ -248,12 +294,12 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
* respect to anything walking the pgd_list, so that they
* never see a partially populated pgd.
*/
- spin_lock_irqsave(&pgd_lock, flags);
+ spin_lock(&pgd_lock);
- pgd_ctor(pgd);
+ pgd_ctor(mm, pgd);
pgd_prepopulate_pmd(mm, pgd, pmds);
- spin_unlock_irqrestore(&pgd_lock, flags);
+ spin_unlock(&pgd_lock);
return pgd;
@@ -273,6 +319,13 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
free_page((unsigned long)pgd);
}
+/*
+ * Used to set accessed or dirty bits in the page table entries
+ * on other architectures. On x86, the accessed and dirty bits
+ * are tracked by hardware. However, do_wp_page calls this function
+ * to also make the pte writeable at the same time the dirty bit is
+ * set. In that case we do actually need to write the PTE.
+ */
int ptep_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep,
pte_t entry, int dirty)
@@ -282,12 +335,35 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
if (changed && dirty) {
*ptep = entry;
pte_update_defer(vma->vm_mm, address, ptep);
- flush_tlb_page(vma, address);
}
return changed;
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int pmdp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp,
+ pmd_t entry, int dirty)
+{
+ int changed = !pmd_same(*pmdp, entry);
+
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+ if (changed && dirty) {
+ *pmdp = entry;
+ pmd_update_defer(vma->vm_mm, address, pmdp);
+ /*
+ * We had a write-protection fault here and changed the pmd
+ * to to more permissive. No need to flush the TLB for that,
+ * #PF is architecturally guaranteed to do that and in the
+ * worst-case we'll generate a spurious fault.
+ */
+ }
+
+ return changed;
+}
+#endif
+
int ptep_test_and_clear_young(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
@@ -303,18 +379,72 @@ int ptep_test_and_clear_young(struct vm_area_struct *vma,
return ret;
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+ unsigned long addr, pmd_t *pmdp)
+{
+ int ret = 0;
+
+ if (pmd_young(*pmdp))
+ ret = test_and_clear_bit(_PAGE_BIT_ACCESSED,
+ (unsigned long *)pmdp);
+
+ if (ret)
+ pmd_update(vma->vm_mm, addr, pmdp);
+
+ return ret;
+}
+#endif
+
int ptep_clear_flush_young(struct vm_area_struct *vma,
unsigned long address, pte_t *ptep)
{
+ /*
+ * On x86 CPUs, clearing the accessed bit without a TLB flush
+ * doesn't cause data corruption. [ It could cause incorrect
+ * page aging and the (mistaken) reclaim of hot pages, but the
+ * chance of that should be relatively low. ]
+ *
+ * So as a performance optimization don't flush the TLB when
+ * clearing the accessed bit, it will eventually be flushed by
+ * a context switch or a VM operation anyway. [ In the rare
+ * event of it not getting flushed for a long time the delay
+ * shouldn't really matter because there's no real memory
+ * pressure for swapout to react to. ]
+ */
+ return ptep_test_and_clear_young(vma, address, ptep);
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
int young;
- young = ptep_test_and_clear_young(vma, address, ptep);
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+ young = pmdp_test_and_clear_young(vma, address, pmdp);
if (young)
- flush_tlb_page(vma, address);
+ flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
return young;
}
+void pmdp_splitting_flush(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ int set;
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ set = !test_and_set_bit(_PAGE_BIT_SPLITTING,
+ (unsigned long *)pmdp);
+ if (set) {
+ pmd_update(vma->vm_mm, address, pmdp);
+ /* need tlb flush only to serialize against gup-fast */
+ flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+ }
+}
+#endif
+
/**
* reserve_top_address - reserves a hole in the top of kernel address space
* @reserve - size of hole to reserve
@@ -326,9 +456,9 @@ void __init reserve_top_address(unsigned long reserve)
{
#ifdef CONFIG_X86_32
BUG_ON(fixmaps_set > 0);
- printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
- (int)-reserve);
- __FIXADDR_TOP = -reserve - PAGE_SIZE;
+ __FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE;
+ printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n",
+ -reserve, __FIXADDR_TOP + PAGE_SIZE);
#endif
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 06:49:45 +0000