diff options
Diffstat (limited to 'arch/tile/mm/pgtable.c')
| -rw-r--r-- | arch/tile/mm/pgtable.c | 170 |
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? */ |