1 // SPDX-License-Identifier: GPL-2.0-only 1
2 // Copyright 2023 Google LLC
3 // Author: Ard Biesheuvel <ardb@google.com>
4
5 #include <linux/types.h>
6 #include <linux/sizes.h>
7
8 #include <asm/memory.h>
9 #include <asm/pgalloc.h>
10 #include <asm/pgtable.h>
11
12 #include "pi.h"
13
14 /**
15 * map_range - Map a contiguous range of physi
16 *
17 * @pte: Address of physical po
18 * allocate page tables f
19 * @start: Virtual address of the
20 * @end: Virtual address of the
21 * @pa: Physical address of th
22 * @prot: Access permissions of
23 * @level: Translation level for
24 * @tbl: The level @level page
25 * @may_use_cont: Whether the use of the
26 * @va_offset: Offset between a physi
27 * in the VA space
28 */
29 void __init map_range(u64 *pte, u64 start, u64
30 int level, pte_t *tbl, b
31 {
32 u64 cmask = (level == 3) ? CONT_PTE_SI
33 u64 protval = pgprot_val(prot) & ~PTE_
34 int lshift = (3 - level) * (PAGE_SHIFT
35 u64 lmask = (PAGE_SIZE << lshift) - 1;
36
37 start &= PAGE_MASK;
38 pa &= PAGE_MASK;
39
40 /* Advance tbl to the entry that cover
41 tbl += (start >> (lshift + PAGE_SHIFT)
42
43 /*
44 * Set the right block/page bits for t
45 * clearing the mapping
46 */
47 if (protval)
48 protval |= (level < 3) ? PMD_T
49
50 while (start < end) {
51 u64 next = min((start | lmask)
52
53 if (level < 3 && (start | next
54 /*
55 * This chunk needs a
56 * table mapping if ne
57 */
58 if (pte_none(*tbl)) {
59 *tbl = __pte(_
60 P
61 *pte += PTRS_P
62 }
63 map_range(pte, start,
64 (pte_t *)(__
65 may_use_cont
66 } else {
67 /*
68 * Start a contiguous
69 * suitably aligned
70 */
71 if (((start | pa) & cm
72 protval |= PTE
73
74 /*
75 * Clear the contiguou
76 * range does not cove
77 */
78 if ((end & ~cmask) <=
79 protval &= ~PT
80
81 /* Put down a block or
82 *tbl = __pte(__phys_to
83 }
84 pa += next - start;
85 start = next;
86 tbl++;
87 }
88 }
89
90 asmlinkage u64 __init create_init_idmap(pgd_t
91 {
92 u64 ptep = (u64)pg_dir + PAGE_SIZE;
93 pgprot_t text_prot = PAGE_KERNEL_ROX;
94 pgprot_t data_prot = PAGE_KERNEL;
95
96 pgprot_val(text_prot) &= ~clrmask;
97 pgprot_val(data_prot) &= ~clrmask;
98
99 map_range(&ptep, (u64)_stext, (u64)__i
100 text_prot, IDMAP_ROOT_LEVEL,
101 map_range(&ptep, (u64)__initdata_begin
102 data_prot, IDMAP_ROOT_LEVEL,
103
104 return ptep;
105 }
106
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