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-rw-r--r--arch/tile/mm/pgtable.c170
1 files changed, 141 insertions, 29 deletions
diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
index 2c850d9..1a2b36f 100644
--- a/arch/tile/mm/pgtable.c
+++ b/arch/tile/mm/pgtable.c
@@ -142,6 +142,76 @@ pte_t *_pte_offset_map(pmd_t *dir, unsigned long address)
}
#endif
+/**
+ * shatter_huge_page() - ensure a given address is mapped by a small page.
+ *
+ * This function converts a huge PTE mapping kernel LOWMEM into a bunch
+ * of small PTEs with the same caching. No cache flush required, but we
+ * must do a global TLB flush.
+ *
+ * Any caller that wishes to modify a kernel mapping that might
+ * have been made with a huge page should call this function,
+ * since doing so properly avoids race conditions with installing the
+ * newly-shattered page and then flushing all the TLB entries.
+ *
+ * @addr: Address at which to shatter any existing huge page.
+ */
+void shatter_huge_page(unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ unsigned long flags = 0; /* happy compiler */
+#ifdef __PAGETABLE_PMD_FOLDED
+ struct list_head *pos;
+#endif
+
+ /* Get a pointer to the pmd entry that we need to change. */
+ addr &= HPAGE_MASK;
+ BUG_ON(pgd_addr_invalid(addr));
+ BUG_ON(addr < PAGE_OFFSET); /* only for kernel LOWMEM */
+ pgd = swapper_pg_dir + pgd_index(addr);
+ pud = pud_offset(pgd, addr);
+ BUG_ON(!pud_present(*pud));
+ pmd = pmd_offset(pud, addr);
+ BUG_ON(!pmd_present(*pmd));
+ if (!pmd_huge_page(*pmd))
+ return;
+
+ /*
+ * Grab the pgd_lock, since we may need it to walk the pgd_list,
+ * and since we need some kind of lock here to avoid races.
+ */
+ spin_lock_irqsave(&pgd_lock, flags);
+ if (!pmd_huge_page(*pmd)) {
+ /* Lost the race to convert the huge page. */
+ spin_unlock_irqrestore(&pgd_lock, flags);
+ return;
+ }
+
+ /* Shatter the huge page into the preallocated L2 page table. */
+ pmd_populate_kernel(&init_mm, pmd,
+ get_prealloc_pte(pte_pfn(*(pte_t *)pmd)));
+
+#ifdef __PAGETABLE_PMD_FOLDED
+ /* Walk every pgd on the system and update the pmd there. */
+ list_for_each(pos, &pgd_list) {
+ pmd_t *copy_pmd;
+ pgd = list_to_pgd(pos) + pgd_index(addr);
+ pud = pud_offset(pgd, addr);
+ copy_pmd = pmd_offset(pud, addr);
+ __set_pmd(copy_pmd, *pmd);
+ }
+#endif
+
+ /* Tell every cpu to notice the change. */
+ flush_remote(0, 0, NULL, addr, HPAGE_SIZE, HPAGE_SIZE,
+ cpu_possible_mask, NULL, 0);
+
+ /* Hold the lock until the TLB flush is finished to avoid races. */
+ spin_unlock_irqrestore(&pgd_lock, flags);
+}
+
/*
* List of all pgd's needed so it can invalidate entries in both cached
* and uncached pgd's. This is essentially codepath-based locking
@@ -184,9 +254,9 @@ static void pgd_ctor(pgd_t *pgd)
BUG_ON(((u64 *)swapper_pg_dir)[pgd_index(MEM_USER_INTRPT)] != 0);
#endif
- clone_pgd_range(pgd + KERNEL_PGD_INDEX_START,
- swapper_pg_dir + KERNEL_PGD_INDEX_START,
- KERNEL_PGD_PTRS);
+ memcpy(pgd + KERNEL_PGD_INDEX_START,
+ swapper_pg_dir + KERNEL_PGD_INDEX_START,
+ KERNEL_PGD_PTRS * sizeof(pgd_t));
pgd_list_add(pgd);
spin_unlock_irqrestore(&pgd_lock, flags);
@@ -220,8 +290,11 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
- gfp_t flags = GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO|__GFP_COMP;
+ gfp_t flags = GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO;
struct page *p;
+#if L2_USER_PGTABLE_ORDER > 0
+ int i;
+#endif
#ifdef CONFIG_HIGHPTE
flags |= __GFP_HIGHMEM;
@@ -231,6 +304,18 @@ struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
if (p == NULL)
return NULL;
+#if L2_USER_PGTABLE_ORDER > 0
+ /*
+ * Make every page have a page_count() of one, not just the first.
+ * We don't use __GFP_COMP since it doesn't look like it works
+ * correctly with tlb_remove_page().
+ */
+ for (i = 1; i < L2_USER_PGTABLE_PAGES; ++i) {
+ init_page_count(p+i);
+ inc_zone_page_state(p+i, NR_PAGETABLE);
+ }
+#endif
+
pgtable_page_ctor(p);
return p;
}
@@ -242,8 +327,15 @@ struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
*/
void pte_free(struct mm_struct *mm, struct page *p)
{
+ int i;
+
pgtable_page_dtor(p);
- __free_pages(p, L2_USER_PGTABLE_ORDER);
+ __free_page(p);
+
+ for (i = 1; i < L2_USER_PGTABLE_PAGES; ++i) {
+ __free_page(p+i);
+ dec_zone_page_state(p+i, NR_PAGETABLE);
+ }
}
void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
@@ -252,8 +344,12 @@ void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
int i;
pgtable_page_dtor(pte);
- for (i = 0; i < L2_USER_PGTABLE_PAGES; ++i)
+ tlb_remove_page(tlb, pte);
+
+ for (i = 1; i < L2_USER_PGTABLE_PAGES; ++i) {
tlb_remove_page(tlb, pte + i);
+ dec_zone_page_state(pte + i, NR_PAGETABLE);
+ }
}
#ifndef __tilegx__
@@ -335,35 +431,51 @@ int get_remote_cache_cpu(pgprot_t prot)
return x + y * smp_width;
}
-void set_pte_order(pte_t *ptep, pte_t pte, int order)
+/*
+ * Convert a kernel VA to a PA and homing information.
+ */
+int va_to_cpa_and_pte(void *va, unsigned long long *cpa, pte_t *pte)
{
- unsigned long pfn = pte_pfn(pte);
- struct page *page = pfn_to_page(pfn);
+ struct page *page = virt_to_page(va);
+ pte_t null_pte = { 0 };
- /* Update the home of a PTE if necessary */
- pte = pte_set_home(pte, page_home(page));
+ *cpa = __pa(va);
+
+ /* Note that this is not writing a page table, just returning a pte. */
+ *pte = pte_set_home(null_pte, page_home(page));
+
+ return 0; /* return non-zero if not hfh? */
+}
+EXPORT_SYMBOL(va_to_cpa_and_pte);
+void __set_pte(pte_t *ptep, pte_t pte)
+{
#ifdef __tilegx__
*ptep = pte;
#else
- /*
- * When setting a PTE, write the high bits first, then write
- * the low bits. This sets the "present" bit only after the
- * other bits are in place. If a particular PTE update
- * involves transitioning from one valid PTE to another, it
- * may be necessary to call set_pte_order() more than once,
- * transitioning via a suitable intermediate state.
- * Note that this sequence also means that if we are transitioning
- * from any migrating PTE to a non-migrating one, we will not
- * see a half-updated PTE with the migrating bit off.
- */
-#if HV_PTE_INDEX_PRESENT >= 32 || HV_PTE_INDEX_MIGRATING >= 32
-# error Must write the present and migrating bits last
-#endif
- ((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32);
- barrier();
- ((u32 *)ptep)[0] = (u32)(pte_val(pte));
-#endif
+# if HV_PTE_INDEX_PRESENT >= 32 || HV_PTE_INDEX_MIGRATING >= 32
+# error Must write the present and migrating bits last
+# endif
+ if (pte_present(pte)) {
+ ((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32);
+ barrier();
+ ((u32 *)ptep)[0] = (u32)(pte_val(pte));
+ } else {
+ ((u32 *)ptep)[0] = (u32)(pte_val(pte));
+ barrier();
+ ((u32 *)ptep)[1] = (u32)(pte_val(pte) >> 32);
+ }
+#endif /* __tilegx__ */
+}
+
+void set_pte(pte_t *ptep, pte_t pte)
+{
+ struct page *page = pfn_to_page(pte_pfn(pte));
+
+ /* Update the home of a PTE if necessary */
+ pte = pte_set_home(pte, page_home(page));
+
+ __set_pte(ptep, pte);
}
/* Can this mm load a PTE with cached_priority set? */