1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * This file contains the routines for initializing the MMU 4 * on the 8xx series of chips. 5 * -- christophe 6 * 7 * Derived from arch/powerpc/mm/40x_mmu.c: 8 */ 9 10 #include <linux/memblock.h> 11 #include <linux/hugetlb.h> 12 13 #include <mm/mmu_decl.h> 14 15 #define IMMR_SIZE (FIX_IMMR_SIZE << PAGE_SHIFT) 16 17 static unsigned long block_mapped_ram; 18 19 /* 20 * Return PA for this VA if it is in an area mapped with LTLBs or fixmap. 21 * Otherwise, returns 0 22 */ 23 phys_addr_t v_block_mapped(unsigned long va) 24 { 25 unsigned long p = PHYS_IMMR_BASE; 26 27 if (va >= VIRT_IMMR_BASE && va < VIRT_IMMR_BASE + IMMR_SIZE) 28 return p + va - VIRT_IMMR_BASE; 29 if (va >= PAGE_OFFSET && va < PAGE_OFFSET + block_mapped_ram) 30 return __pa(va); 31 return 0; 32 } 33 34 /* 35 * Return VA for a given PA mapped with LTLBs or fixmap 36 * Return 0 if not mapped 37 */ 38 unsigned long p_block_mapped(phys_addr_t pa) 39 { 40 unsigned long p = PHYS_IMMR_BASE; 41 42 if (pa >= p && pa < p + IMMR_SIZE) 43 return VIRT_IMMR_BASE + pa - p; 44 if (pa < block_mapped_ram) 45 return (unsigned long)__va(pa); 46 return 0; 47 } 48 49 static pte_t __init *early_hugepd_alloc_kernel(hugepd_t *pmdp, unsigned long va) 50 { 51 if (hpd_val(*pmdp) == 0) { 52 pte_t *ptep = memblock_alloc(sizeof(pte_basic_t), SZ_4K); 53 54 if (!ptep) 55 return NULL; 56 57 hugepd_populate_kernel((hugepd_t *)pmdp, ptep, PAGE_SHIFT_8M); 58 hugepd_populate_kernel((hugepd_t *)pmdp + 1, ptep, PAGE_SHIFT_8M); 59 } 60 return hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT); 61 } 62 63 static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa, 64 pgprot_t prot, int psize, bool new) 65 { 66 pmd_t *pmdp = pmd_off_k(va); 67 pte_t *ptep; 68 69 if (WARN_ON(psize != MMU_PAGE_512K && psize != MMU_PAGE_8M)) 70 return -EINVAL; 71 72 if (new) { 73 if (WARN_ON(slab_is_available())) 74 return -EINVAL; 75 76 if (psize == MMU_PAGE_512K) 77 ptep = early_pte_alloc_kernel(pmdp, va); 78 else 79 ptep = early_hugepd_alloc_kernel((hugepd_t *)pmdp, va); 80 } else { 81 if (psize == MMU_PAGE_512K) 82 ptep = pte_offset_kernel(pmdp, va); 83 else 84 ptep = hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT); 85 } 86 87 if (WARN_ON(!ptep)) 88 return -ENOMEM; 89 90 /* The PTE should never be already present */ 91 if (new && WARN_ON(pte_present(*ptep) && pgprot_val(prot))) 92 return -EINVAL; 93 94 set_huge_pte_at(&init_mm, va, ptep, pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot))); 95 96 return 0; 97 } 98 99 /* 100 * MMU_init_hw does the chip-specific initialization of the MMU hardware. 101 */ 102 void __init MMU_init_hw(void) 103 { 104 } 105 106 static bool immr_is_mapped __initdata; 107 108 void __init mmu_mapin_immr(void) 109 { 110 if (immr_is_mapped) 111 return; 112 113 immr_is_mapped = true; 114 115 __early_map_kernel_hugepage(VIRT_IMMR_BASE, PHYS_IMMR_BASE, 116 PAGE_KERNEL_NCG, MMU_PAGE_512K, true); 117 } 118 119 static void mmu_mapin_ram_chunk(unsigned long offset, unsigned long top, 120 pgprot_t prot, bool new) 121 { 122 unsigned long v = PAGE_OFFSET + offset; 123 unsigned long p = offset; 124 125 WARN_ON(!IS_ALIGNED(offset, SZ_512K) || !IS_ALIGNED(top, SZ_512K)); 126 127 for (; p < ALIGN(p, SZ_8M) && p < top; p += SZ_512K, v += SZ_512K) 128 __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new); 129 for (; p < ALIGN_DOWN(top, SZ_8M) && p < top; p += SZ_8M, v += SZ_8M) 130 __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new); 131 for (; p < ALIGN_DOWN(top, SZ_512K) && p < top; p += SZ_512K, v += SZ_512K) 132 __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new); 133 134 if (!new) 135 flush_tlb_kernel_range(PAGE_OFFSET + v, PAGE_OFFSET + top); 136 } 137 138 unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) 139 { 140 unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M); 141 unsigned long sinittext = __pa(_sinittext); 142 bool strict_boundary = strict_kernel_rwx_enabled() || debug_pagealloc_enabled_or_kfence(); 143 unsigned long boundary = strict_boundary ? sinittext : etext8; 144 unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M); 145 146 WARN_ON(top < einittext8); 147 148 mmu_mapin_immr(); 149 150 mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, true); 151 if (debug_pagealloc_enabled_or_kfence()) { 152 top = boundary; 153 } else { 154 mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL_TEXT, true); 155 mmu_mapin_ram_chunk(einittext8, top, PAGE_KERNEL, true); 156 } 157 158 if (top > SZ_32M) 159 memblock_set_current_limit(top); 160 161 block_mapped_ram = top; 162 163 return top; 164 } 165 166 void mmu_mark_initmem_nx(void) 167 { 168 unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M); 169 unsigned long sinittext = __pa(_sinittext); 170 unsigned long boundary = strict_kernel_rwx_enabled() ? sinittext : etext8; 171 unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M); 172 173 if (!debug_pagealloc_enabled_or_kfence()) 174 mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false); 175 176 mmu_pin_tlb(block_mapped_ram, false); 177 } 178 179 #ifdef CONFIG_STRICT_KERNEL_RWX 180 void mmu_mark_rodata_ro(void) 181 { 182 unsigned long sinittext = __pa(_sinittext); 183 184 mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false); 185 if (IS_ENABLED(CONFIG_PIN_TLB_DATA)) 186 mmu_pin_tlb(block_mapped_ram, true); 187 } 188 #endif 189 190 void __init setup_initial_memory_limit(phys_addr_t first_memblock_base, 191 phys_addr_t first_memblock_size) 192 { 193 /* We don't currently support the first MEMBLOCK not mapping 0 194 * physical on those processors 195 */ 196 BUG_ON(first_memblock_base != 0); 197 198 /* 8xx can only access 32MB at the moment */ 199 memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_32M)); 200 } 201 202 int pud_clear_huge(pud_t *pud) 203 { 204 return 0; 205 } 206 207 int pmd_clear_huge(pmd_t *pmd) 208 { 209 return 0; 210 } 211