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