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>
  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 pmd_populate(struct mm_struct *mm, pmd_t *pmd,
  45                                 pgtable_t pte)
  46 {
  47         /*
  48          * Conveniently, zero in 3 LSB means indirect 4K page table.
  49          * Not so convenient when you're trying to vary the page size.
  50          */
  51         set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
  52                 HEXAGON_L1_PTE_SIZE));
  53 }
  54
  55 /*
  56  * Other architectures seem to have ways of making all processes
  57  * share the same pmd's for their kernel mappings, but the v0.3
  58  * Hexagon VM spec has a "monolithic" L1 table for user and kernel
  59  * segments.  We track "generations" of the kernel map to minimize
  60  * overhead, and update the "slave" copies of the kernel mappings
  61  * as part of switch_mm.  However, we still need to update the
  62  * kernel map of the active thread who's calling pmd_populate_kernel...
  63  */
  64 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
  65                                        pte_t *pte)
  66 {
  67         extern spinlock_t kmap_gen_lock;
  68         pmd_t *ppmd;
  69         int pmdindex;
  70
  71         spin_lock(&kmap_gen_lock);
  72         kmap_generation++;
  73         mm->context.generation = kmap_generation;
  74         current->active_mm->context.generation = kmap_generation;
  75         spin_unlock(&kmap_gen_lock);
  76
  77         set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
  78
  79         /*
  80          * Now the "slave" copy of the current thread.
  81          * This is pointer arithmetic, not byte addresses!
  82          */
  83         pmdindex = (pgd_t *)pmd - mm->pgd;
  84         ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
  85         set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
  86         if (pmdindex > max_kernel_seg)
  87                 max_kernel_seg = pmdindex;
  88 }
  89
  90 #define __pte_free_tlb(tlb, pte, addr)          \
  91 do {                                            \
  92         pgtable_pte_page_dtor((pte));           \
  93         tlb_remove_page((tlb), (pte));          \
  94 } while (0)
  95
  96 #endif