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 phys_addr_t (*arch_virt_to_idmap) (unsigned long x); 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_idmap(text_start); 72 end = virt_to_idmap(text_end); 73 pr_info("Setting up static identity map for 0x%lx - 0x%lx\n", addr, end); 74 75 prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF; 76 77 if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale()) 78 prot |= PMD_BIT4; 79 80 pgd += pgd_index(addr); 81 do { 82 next = pgd_addr_end(addr, end); 83 idmap_add_pud(pgd, addr, next, prot); 84 } while (pgd++, addr = next, addr != end); 85 } 86 87 extern char __idmap_text_start[], __idmap_text_end[]; 88 89 static int __init init_static_idmap(void) 90 { 91 idmap_pgd = pgd_alloc(&init_mm); 92 if (!idmap_pgd) 93 return -ENOMEM; 94 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