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 #include <asm/virt.h> 12 13 pgd_t *idmap_pgd; 14 15 #ifdef CONFIG_ARM_LPAE 16 static 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 */ 40 static 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 53 static 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 65 static 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_phys(text_start); 72 end = virt_to_phys(text_end); 73 74 prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF; 75 76 if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) 77 prot |= PMD_BIT4; 78 79 pgd += pgd_index(addr); 80 do { 81 next = pgd_addr_end(addr, end); 82 idmap_add_pud(pgd, addr, next, prot); 83 } while (pgd++, addr = next, addr != end); 84 } 85 86 #if defined(CONFIG_ARM_VIRT_EXT) && defined(CONFIG_ARM_LPAE) 87 pgd_t *hyp_pgd; 88 89 extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; 90 91 static int __init init_static_idmap_hyp(void) 92 { 93 hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL); 94 if (!hyp_pgd) 95 return -ENOMEM; 96 97 pr_info("Setting up static HYP identity map for 0x%p - 0x%p\n", 98 __hyp_idmap_text_start, __hyp_idmap_text_end); 99 identity_mapping_add(hyp_pgd, __hyp_idmap_text_start, 100 __hyp_idmap_text_end, PMD_SECT_AP1); 101 102 return 0; 103 } 104 #else 105 static int __init init_static_idmap_hyp(void) 106 { 107 return 0; 108 } 109 #endif 110 111 extern char __idmap_text_start[], __idmap_text_end[]; 112 113 static int __init init_static_idmap(void) 114 { 115 int ret; 116 117 idmap_pgd = pgd_alloc(&init_mm); 118 if (!idmap_pgd) 119 return -ENOMEM; 120 121 pr_info("Setting up static identity map for 0x%p - 0x%p\n", 122 __idmap_text_start, __idmap_text_end); 123 identity_mapping_add(idmap_pgd, __idmap_text_start, 124 __idmap_text_end, 0); 125 126 ret = init_static_idmap_hyp(); 127 128 /* Flush L1 for the hardware to see this page table content */ 129 flush_cache_louis(); 130 131 return ret; 132 } 133 early_initcall(init_static_idmap); 134 135 /* 136 * In order to soft-boot, we need to switch to a 1:1 mapping for the 137 * cpu_reset functions. This will then ensure that we have predictable 138 * results when turning off the mmu. 139 */ 140 void setup_mm_for_reboot(void) 141 { 142 /* Switch to the identity mapping. */ 143 cpu_switch_mm(idmap_pgd, &init_mm); 144 145 #ifdef CONFIG_CPU_HAS_ASID 146 /* 147 * We don't have a clean ASID for the identity mapping, which 148 * may clash with virtual addresses of the previous page tables 149 * and therefore potentially in the TLB. 150 */ 151 local_flush_tlb_all(); 152 #endif 153 } 154