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 12 pgd_t *idmap_pgd; 13 14 #ifdef CONFIG_ARM_LPAE 15 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end, 16 unsigned long prot) 17 { 18 pmd_t *pmd; 19 unsigned long next; 20 21 if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) { 22 pmd = pmd_alloc_one(&init_mm, addr); 23 if (!pmd) { 24 pr_warning("Failed to allocate identity pmd.\n"); 25 return; 26 } 27 pud_populate(&init_mm, pud, pmd); 28 pmd += pmd_index(addr); 29 } else 30 pmd = pmd_offset(pud, addr); 31 32 do { 33 next = pmd_addr_end(addr, end); 34 *pmd = __pmd((addr & PMD_MASK) | prot); 35 flush_pmd_entry(pmd); 36 } while (pmd++, addr = next, addr != end); 37 } 38 #else /* !CONFIG_ARM_LPAE */ 39 static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end, 40 unsigned long prot) 41 { 42 pmd_t *pmd = pmd_offset(pud, addr); 43 44 addr = (addr & PMD_MASK) | prot; 45 pmd[0] = __pmd(addr); 46 addr += SECTION_SIZE; 47 pmd[1] = __pmd(addr); 48 flush_pmd_entry(pmd); 49 } 50 #endif /* CONFIG_ARM_LPAE */ 51 52 static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end, 53 unsigned long prot) 54 { 55 pud_t *pud = pud_offset(pgd, addr); 56 unsigned long next; 57 58 do { 59 next = pud_addr_end(addr, end); 60 idmap_add_pmd(pud, addr, next, prot); 61 } while (pud++, addr = next, addr != end); 62 } 63 64 static void identity_mapping_add(pgd_t *pgd, const char *text_start, 65 const char *text_end, unsigned long prot) 66 { 67 unsigned long addr, end; 68 unsigned long next; 69 70 addr = virt_to_phys(text_start); 71 end = virt_to_phys(text_end); 72 73 prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF; 74 75 if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) 76 prot |= PMD_BIT4; 77 78 pgd += pgd_index(addr); 79 do { 80 next = pgd_addr_end(addr, end); 81 idmap_add_pud(pgd, addr, next, prot); 82 } while (pgd++, addr = next, addr != end); 83 } 84 85 extern char __idmap_text_start[], __idmap_text_end[]; 86 87 static int __init init_static_idmap(void) 88 { 89 idmap_pgd = pgd_alloc(&init_mm); 90 if (!idmap_pgd) 91 return -ENOMEM; 92 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, 96 __idmap_text_end, 0); 97 98 /* Flush L1 for the hardware to see this page table content */ 99 flush_cache_louis(); 100 101 return 0; 102 } 103 early_initcall(init_static_idmap); 104 105 /* 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. 109 */ 110 void setup_mm_for_reboot(void) 111 { 112 /* Switch to the identity mapping. */ 113 cpu_switch_mm(idmap_pgd, &init_mm); 114 local_flush_bp_all(); 115 116 #ifdef CONFIG_CPU_HAS_ASID 117 /* 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. 121 */ 122 local_flush_tlb_all(); 123 #endif 124 } 125