1 /*
2 * Copyright 2005, Paul Mackerras, IBM Corporation.
3 * Copyright 2009, Benjamin Herrenschmidt, IBM Corporation.
4 * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12 #include <linux/sched.h>
13 #include <linux/memblock.h>
14 #include <asm/pgalloc.h>
15 #include <asm/tlb.h>
16 #include <asm/dma.h>
17
18 #include "mmu_decl.h"
19
20 #ifdef CONFIG_SPARSEMEM_VMEMMAP
21 /*
22 * On Book3E CPUs, the vmemmap is currently mapped in the top half of
23 * the vmalloc space using normal page tables, though the size of
24 * pages encoded in the PTEs can be different
25 */
vmemmap_create_mapping(unsigned long start,unsigned long page_size,unsigned long phys)26 int __meminit vmemmap_create_mapping(unsigned long start,
27 unsigned long page_size,
28 unsigned long phys)
29 {
30 /* Create a PTE encoding without page size */
31 unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
32 _PAGE_KERNEL_RW;
33
34 /* PTEs only contain page size encodings up to 32M */
35 BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
36
37 /* Encode the size in the PTE */
38 flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
39
40 /* For each PTE for that area, map things. Note that we don't
41 * increment phys because all PTEs are of the large size and
42 * thus must have the low bits clear
43 */
44 for (i = 0; i < page_size; i += PAGE_SIZE)
45 BUG_ON(map_kernel_page(start + i, phys, flags));
46
47 return 0;
48 }
49
50 #ifdef CONFIG_MEMORY_HOTPLUG
vmemmap_remove_mapping(unsigned long start,unsigned long page_size)51 void vmemmap_remove_mapping(unsigned long start,
52 unsigned long page_size)
53 {
54 }
55 #endif
56 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
57
early_alloc_pgtable(unsigned long size)58 static __ref void *early_alloc_pgtable(unsigned long size)
59 {
60 void *pt;
61
62 pt = __va(memblock_alloc_base(size, size, __pa(MAX_DMA_ADDRESS)));
63 memset(pt, 0, size);
64
65 return pt;
66 }
67
68 /*
69 * map_kernel_page currently only called by __ioremap
70 * map_kernel_page adds an entry to the ioremap page table
71 * and adds an entry to the HPT, possibly bolting it
72 */
map_kernel_page(unsigned long ea,unsigned long pa,unsigned long flags)73 int map_kernel_page(unsigned long ea, unsigned long pa, unsigned long flags)
74 {
75 pgd_t *pgdp;
76 pud_t *pudp;
77 pmd_t *pmdp;
78 pte_t *ptep;
79
80 BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
81 if (slab_is_available()) {
82 pgdp = pgd_offset_k(ea);
83 pudp = pud_alloc(&init_mm, pgdp, ea);
84 if (!pudp)
85 return -ENOMEM;
86 pmdp = pmd_alloc(&init_mm, pudp, ea);
87 if (!pmdp)
88 return -ENOMEM;
89 ptep = pte_alloc_kernel(pmdp, ea);
90 if (!ptep)
91 return -ENOMEM;
92 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
93 __pgprot(flags)));
94 } else {
95 pgdp = pgd_offset_k(ea);
96 #ifndef __PAGETABLE_PUD_FOLDED
97 if (pgd_none(*pgdp)) {
98 pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
99 BUG_ON(pudp == NULL);
100 pgd_populate(&init_mm, pgdp, pudp);
101 }
102 #endif /* !__PAGETABLE_PUD_FOLDED */
103 pudp = pud_offset(pgdp, ea);
104 if (pud_none(*pudp)) {
105 pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
106 BUG_ON(pmdp == NULL);
107 pud_populate(&init_mm, pudp, pmdp);
108 }
109 pmdp = pmd_offset(pudp, ea);
110 if (!pmd_present(*pmdp)) {
111 ptep = early_alloc_pgtable(PAGE_SIZE);
112 BUG_ON(ptep == NULL);
113 pmd_populate_kernel(&init_mm, pmdp, ptep);
114 }
115 ptep = pte_offset_kernel(pmdp, ea);
116 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
117 __pgprot(flags)));
118 }
119
120 smp_wmb();
121 return 0;
122 }
123