| 1 |
|
| 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_alloc(mm, 0);
|
| 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 |
|
| 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 | tlb_remove_ptdesc((tlb), page_ptdesc(pte))
|
| 92 |
|
| 93 | #endif
|