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