1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm_types.h>
#include <asm/cputype.h>
#include <asm/idmap.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/sections.h>
#include <asm/system_info.h>
/*
* Note: accesses outside of the kernel image and the identity map area
* are not supported on any CPU using the idmap tables as its current
* page tables.
*/
pgd_t *idmap_pgd __ro_after_init;
long long arch_phys_to_idmap_offset __ro_after_init;
#ifdef CONFIG_ARM_LPAE
static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
unsigned long prot)
{
pmd_t *pmd;
unsigned long next;
if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
pmd = pmd_alloc_one(&init_mm, addr);
if (!pmd) {
pr_warn("Failed to allocate identity pmd.\n");
return;
}
/*
* Copy the original PMD to ensure that the PMD entries for
* the kernel image are preserved.
*/
if (!pud_none(*pud))
memcpy(pmd, pmd_offset(pud, 0),
PTRS_PER_PMD * sizeof(pmd_t));
pud_populate(&init_mm, pud, pmd);
pmd += pmd_index(addr);
} else
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
*pmd = __pmd((addr & PMD_MASK) | prot);
flush_pmd_entry(pmd);
} while (pmd++, addr = next, addr != end);
}
#else /* !CONFIG_ARM_LPAE */
static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
unsigned long prot)
{
pmd_t *pmd = pmd_offset(pud, addr);
addr = (addr & PMD_MASK) | prot;
pmd[0] = __pmd(addr);
addr += SECTION_SIZE;
pmd[1] = __pmd(addr);
flush_pmd_entry(pmd);
}
#endif /* CONFIG_ARM_LPAE */
static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
unsigned long prot)
{
pud_t *pud = pud_offset(pgd, addr);
unsigned long next;
do {
next = pud_addr_end(addr, end);
idmap_add_pmd(pud, addr, next, prot);
} while (pud++, addr = next, addr != end);
}
static void identity_mapping_add(pgd_t *pgd, const char *text_start,
const char *text_end, unsigned long prot)
{
unsigned long addr, end;
unsigned long next;
addr = virt_to_idmap(text_start);
end = virt_to_idmap(text_end);
pr_info("Setting up static identity map for 0x%lx - 0x%lx\n", addr, end);
prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale_family())
prot |= PMD_BIT4;
pgd += pgd_index(addr);
do {
next = pgd_addr_end(addr, end);
idmap_add_pud(pgd, addr, next, prot);
} while (pgd++, addr = next, addr != end);
}
extern char __idmap_text_start[], __idmap_text_end[];
static int __init init_static_idmap(void)
{
idmap_pgd = pgd_alloc(&init_mm);
if (!idmap_pgd)
return -ENOMEM;
identity_mapping_add(idmap_pgd, __idmap_text_start,
__idmap_text_end, 0);
/* Flush L1 for the hardware to see this page table content */
flush_cache_louis();
return 0;
}
early_initcall(init_static_idmap);
/*
* In order to soft-boot, we need to switch to a 1:1 mapping for the
* cpu_reset functions. This will then ensure that we have predictable
* results when turning off the mmu.
*/
void setup_mm_for_reboot(void)
{
/* Switch to the identity mapping. */
cpu_switch_mm(idmap_pgd, &init_mm);
local_flush_bp_all();
#ifdef CONFIG_CPU_HAS_ASID
/*
* We don't have a clean ASID for the identity mapping, which
* may clash with virtual addresses of the previous page tables
* and therefore potentially in the TLB.
*/
local_flush_tlb_all();
#endif
}
|
