1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 */
 14
 15#ifndef _ASM_TILE_PGALLOC_H
 16#define _ASM_TILE_PGALLOC_H
 17
 18#include <linux/threads.h>
 19#include <linux/mm.h>
 20#include <linux/mmzone.h>
 21#include <asm/fixmap.h>
 22#include <hv/hypervisor.h>
 23
 24/* Bits for the size of the second-level page table. */
 25#define L2_KERNEL_PGTABLE_SHIFT \
 26  (HV_LOG2_PAGE_SIZE_LARGE - HV_LOG2_PAGE_SIZE_SMALL + HV_LOG2_PTE_SIZE)
 27
 28/* We currently allocate user L2 page tables by page (unlike kernel L2s). */
 29#if L2_KERNEL_PGTABLE_SHIFT < HV_LOG2_PAGE_SIZE_SMALL
 30#define L2_USER_PGTABLE_SHIFT HV_LOG2_PAGE_SIZE_SMALL
 31#else
 32#define L2_USER_PGTABLE_SHIFT L2_KERNEL_PGTABLE_SHIFT
 33#endif
 34
 35/* How many pages do we need, as an "order", for a user L2 page table? */
 36#define L2_USER_PGTABLE_ORDER (L2_USER_PGTABLE_SHIFT - HV_LOG2_PAGE_SIZE_SMALL)
 37
 38/* How big is a kernel L2 page table? */
 39#define L2_KERNEL_PGTABLE_SIZE (1 << L2_KERNEL_PGTABLE_SHIFT)
 40
 41static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
 42{
 43#ifdef CONFIG_64BIT
 44	set_pte(pmdp, pmd);
 45#else
 46	set_pte(&pmdp->pud.pgd, pmd.pud.pgd);
 47#endif
 48}
 49
 50static inline void pmd_populate_kernel(struct mm_struct *mm,
 51				       pmd_t *pmd, pte_t *ptep)
 52{
 53	set_pmd(pmd, ptfn_pmd(__pa(ptep) >> HV_LOG2_PAGE_TABLE_ALIGN,
 54			      __pgprot(_PAGE_PRESENT)));
 55}
 56
 57static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 58				pgtable_t page)
 59{
 60	set_pmd(pmd, ptfn_pmd(HV_PFN_TO_PTFN(page_to_pfn(page)),
 61			      __pgprot(_PAGE_PRESENT)));
 62}
 63
 64/*
 65 * Allocate and free page tables.
 66 */
 67
 68extern pgd_t *pgd_alloc(struct mm_struct *mm);
 69extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
 70
 71extern pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address);
 72extern void pte_free(struct mm_struct *mm, struct page *pte);
 73
 74#define pmd_pgtable(pmd) pmd_page(pmd)
 75
 76static inline pte_t *
 77pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 78{
 79	return pfn_to_kaddr(page_to_pfn(pte_alloc_one(mm, address)));
 80}
 81
 82static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 83{
 84	BUG_ON((unsigned long)pte & (PAGE_SIZE-1));
 85	pte_free(mm, virt_to_page(pte));
 86}
 87
 88extern void __pte_free_tlb(struct mmu_gather *tlb, struct page *pte,
 89			   unsigned long address);
 90
 91#define check_pgt_cache()	do { } while (0)
 92
 93/*
 94 * Get the small-page pte_t lowmem entry for a given pfn.
 95 * This may or may not be in use, depending on whether the initial
 96 * huge-page entry for the page has already been shattered.
 97 */
 98pte_t *get_prealloc_pte(unsigned long pfn);
 99
100/* During init, we can shatter kernel huge pages if needed. */
101void shatter_pmd(pmd_t *pmd);
102
103/* After init, a more complex technique is required. */
104void shatter_huge_page(unsigned long addr);
105
106#ifdef __tilegx__
107/* We share a single page allocator for both L1 and L2 page tables. */
108#if HV_L1_SIZE != HV_L2_SIZE
109# error Rework assumption that L1 and L2 page tables are same size.
110#endif
111#define L1_USER_PGTABLE_ORDER L2_USER_PGTABLE_ORDER
112#define pud_populate(mm, pud, pmd) \
113  pmd_populate_kernel((mm), (pmd_t *)(pud), (pte_t *)(pmd))
114#define pmd_alloc_one(mm, addr) \
115  ((pmd_t *)page_to_virt(pte_alloc_one((mm), (addr))))
116#define pmd_free(mm, pmdp) \
117  pte_free((mm), virt_to_page(pmdp))
118#define __pmd_free_tlb(tlb, pmdp, address) \
119  __pte_free_tlb((tlb), virt_to_page(pmdp), (address))
120#endif
121
122#endif /* _ASM_TILE_PGALLOC_H */