1 #include <linux/kernel.h>
2
3 #include <asm/cputype.h>
4 #include <asm/idmap.h>
5 #include <asm/pgalloc.h>
6 #include <asm/pgtable.h>
7 #include <asm/sections.h>
8 #include <asm/system_info.h>
9
10 pgd_t *idmap_pgd;
11
12 #ifdef CONFIG_ARM_LPAE
idmap_add_pmd(pud_t * pud,unsigned long addr,unsigned long end,unsigned long prot)13 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
14 unsigned long prot)
15 {
16 pmd_t *pmd;
17 unsigned long next;
18
19 if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
20 pmd = pmd_alloc_one(&init_mm, addr);
21 if (!pmd) {
22 pr_warning("Failed to allocate identity pmd.\n");
23 return;
24 }
25 pud_populate(&init_mm, pud, pmd);
26 pmd += pmd_index(addr);
27 } else
28 pmd = pmd_offset(pud, addr);
29
30 do {
31 next = pmd_addr_end(addr, end);
32 *pmd = __pmd((addr & PMD_MASK) | prot);
33 flush_pmd_entry(pmd);
34 } while (pmd++, addr = next, addr != end);
35 }
36 #else /* !CONFIG_ARM_LPAE */
idmap_add_pmd(pud_t * pud,unsigned long addr,unsigned long end,unsigned long prot)37 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
38 unsigned long prot)
39 {
40 pmd_t *pmd = pmd_offset(pud, addr);
41
42 addr = (addr & PMD_MASK) | prot;
43 pmd[0] = __pmd(addr);
44 addr += SECTION_SIZE;
45 pmd[1] = __pmd(addr);
46 flush_pmd_entry(pmd);
47 }
48 #endif /* CONFIG_ARM_LPAE */
49
idmap_add_pud(pgd_t * pgd,unsigned long addr,unsigned long end,unsigned long prot)50 static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
51 unsigned long prot)
52 {
53 pud_t *pud = pud_offset(pgd, addr);
54 unsigned long next;
55
56 do {
57 next = pud_addr_end(addr, end);
58 idmap_add_pmd(pud, addr, next, prot);
59 } while (pud++, addr = next, addr != end);
60 }
61
identity_mapping_add(pgd_t * pgd,unsigned long addr,unsigned long end)62 static void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
63 {
64 unsigned long prot, next;
65
66 prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
67 if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
68 prot |= PMD_BIT4;
69
70 pgd += pgd_index(addr);
71 do {
72 next = pgd_addr_end(addr, end);
73 idmap_add_pud(pgd, addr, next, prot);
74 } while (pgd++, addr = next, addr != end);
75 }
76
77 extern char __idmap_text_start[], __idmap_text_end[];
78
init_static_idmap(void)79 static int __init init_static_idmap(void)
80 {
81 phys_addr_t idmap_start, idmap_end;
82
83 idmap_pgd = pgd_alloc(&init_mm);
84 if (!idmap_pgd)
85 return -ENOMEM;
86
87 /* Add an identity mapping for the physical address of the section. */
88 idmap_start = virt_to_phys((void *)__idmap_text_start);
89 idmap_end = virt_to_phys((void *)__idmap_text_end);
90
91 pr_info("Setting up static identity map for 0x%llx - 0x%llx\n",
92 (long long)idmap_start, (long long)idmap_end);
93 identity_mapping_add(idmap_pgd, idmap_start, idmap_end);
94
95 return 0;
96 }
97 early_initcall(init_static_idmap);
98
99 /*
100 * In order to soft-boot, we need to switch to a 1:1 mapping for the
101 * cpu_reset functions. This will then ensure that we have predictable
102 * results when turning off the mmu.
103 */
setup_mm_for_reboot(void)104 void setup_mm_for_reboot(void)
105 {
106 /* Clean and invalidate L1. */
107 flush_cache_all();
108
109 /* Switch to the identity mapping. */
110 cpu_switch_mm(idmap_pgd, &init_mm);
111
112 /* Flush the TLB. */
113 local_flush_tlb_all();
114 }
115