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 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 */ 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 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 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 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 /* Flush L1 for the hardware to see this page table content */ 96 flush_cache_louis(); 97 98 return 0; 99 } 100 early_initcall(init_static_idmap); 101 102 /* 103 * In order to soft-boot, we need to switch to a 1:1 mapping for the 104 * cpu_reset functions. This will then ensure that we have predictable 105 * results when turning off the mmu. 106 */ 107 void setup_mm_for_reboot(void) 108 { 109 /* Switch to the identity mapping. */ 110 cpu_switch_mm(idmap_pgd, &init_mm); 111 112 #ifdef CONFIG_CPU_HAS_ASID 113 /* 114 * We don't have a clean ASID for the identity mapping, which 115 * may clash with virtual addresses of the previous page tables 116 * and therefore potentially in the TLB. 117 */ 118 local_flush_tlb_all(); 119 #endif 120 } 121