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 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 */ 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 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 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 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 */ 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