1 #include <linux/module.h>
2 #include <linux/kernel.h>
3 #include <linux/slab.h>
5 #include <asm/cputype.h>
7 #include <asm/pgalloc.h>
8 #include <asm/pgtable.h>
9 #include <asm/sections.h>
10 #include <asm/system_info.h>
14 #ifdef CONFIG_ARM_LPAE
15 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
21 if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
22 pmd = pmd_alloc_one(&init_mm, addr);
24 pr_warning("Failed to allocate identity pmd.\n");
27 pud_populate(&init_mm, pud, pmd);
28 pmd += pmd_index(addr);
30 pmd = pmd_offset(pud, addr);
33 next = pmd_addr_end(addr, end);
34 *pmd = __pmd((addr & PMD_MASK) | prot);
36 } while (pmd++, addr = next, addr != end);
38 #else /* !CONFIG_ARM_LPAE */
39 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
42 pmd_t *pmd = pmd_offset(pud, addr);
44 addr = (addr & PMD_MASK) | prot;
50 #endif /* CONFIG_ARM_LPAE */
52 static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
55 pud_t *pud = pud_offset(pgd, addr);
59 next = pud_addr_end(addr, end);
60 idmap_add_pmd(pud, addr, next, prot);
61 } while (pud++, addr = next, addr != end);
64 static void identity_mapping_add(pgd_t *pgd, const char *text_start,
65 const char *text_end, unsigned long prot)
67 unsigned long addr, end;
70 addr = virt_to_phys(text_start);
71 end = virt_to_phys(text_end);
73 prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
75 if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
78 pgd += pgd_index(addr);
80 next = pgd_addr_end(addr, end);
81 idmap_add_pud(pgd, addr, next, prot);
82 } while (pgd++, addr = next, addr != end);
85 extern char __idmap_text_start[], __idmap_text_end[];
87 static int __init init_static_idmap(void)
89 idmap_pgd = pgd_alloc(&init_mm);
93 pr_info("Setting up static identity map for 0x%p - 0x%p\n",
94 __idmap_text_start, __idmap_text_end);
95 identity_mapping_add(idmap_pgd, __idmap_text_start,
98 /* Flush L1 for the hardware to see this page table content */
103 early_initcall(init_static_idmap);
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.
110 void setup_mm_for_reboot(void)
112 /* Switch to the identity mapping. */
113 cpu_switch_mm(idmap_pgd, &init_mm);
114 local_flush_bp_all();
116 #ifdef CONFIG_CPU_HAS_ASID
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.
122 local_flush_tlb_all();