arch/hexagon/include/asm/pgalloc.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Page table support for the Hexagon architecture
   4  *
   5  * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   6  */
   7
   8 #ifndef _ASM_PGALLOC_H
   9 #define _ASM_PGALLOC_H
  10
  11 #include <asm/mem-layout.h>
  12 #include <asm/atomic.h>
  13
  14 #include <asm-generic/pgalloc.h>        /* for pte_{alloc,free}_one */
  15
  16 extern unsigned long long kmap_generation;
  17
  18 /*
  19  * Page table creation interface
  20  */
  21 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
  22 {
  23         pgd_t *pgd;
  24
  25         pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
  26
  27         /*
  28          * There may be better ways to do this, but to ensure
  29          * that new address spaces always contain the kernel
  30          * base mapping, and to ensure that the user area is
  31          * initially marked invalid, initialize the new map
  32          * map with a copy of the kernel's persistent map.
  33          */
  34
  35         memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t));
  36         mm->context.generation = kmap_generation;
  37
  38         /* Physical version is what is passed to virtual machine on switch */
  39         mm->context.ptbase = __pa(pgd);
  40
  41         return pgd;
  42 }
  43
  44 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
  45 {
  46         free_page((unsigned long) pgd);
  47 }
  48
  49 static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
  50                                 pgtable_t pte)
  51 {
  52         /*
  53          * Conveniently, zero in 3 LSB means indirect 4K page table.
  54          * Not so convenient when you're trying to vary the page size.
  55          */
  56         set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
  57                 HEXAGON_L1_PTE_SIZE));
  58 }
  59
  60 /*
  61  * Other architectures seem to have ways of making all processes
  62  * share the same pmd's for their kernel mappings, but the v0.3
  63  * Hexagon VM spec has a "monolithic" L1 table for user and kernel
  64  * segments.  We track "generations" of the kernel map to minimize
  65  * overhead, and update the "slave" copies of the kernel mappings
  66  * as part of switch_mm.  However, we still need to update the
  67  * kernel map of the active thread who's calling pmd_populate_kernel...
  68  */
  69 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
  70                                        pte_t *pte)
  71 {
  72         extern spinlock_t kmap_gen_lock;
  73         pmd_t *ppmd;
  74         int pmdindex;
  75
  76         spin_lock(&kmap_gen_lock);
  77         kmap_generation++;
  78         mm->context.generation = kmap_generation;
  79         current->active_mm->context.generation = kmap_generation;
  80         spin_unlock(&kmap_gen_lock);
  81
  82         set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
  83
  84         /*
  85          * Now the "slave" copy of the current thread.
  86          * This is pointer arithmetic, not byte addresses!
  87          */
  88         pmdindex = (pgd_t *)pmd - mm->pgd;
  89         ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
  90         set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
  91         if (pmdindex > max_kernel_seg)
  92                 max_kernel_seg = pmdindex;
  93 }
  94
  95 #define __pte_free_tlb(tlb, pte, addr)          \
  96 do {                                            \
  97         pgtable_pte_page_dtor((pte));           \
  98         tlb_remove_page((tlb), (pte));          \
  99 } while (0)
 100
 101 #endif