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/mmu_context.h> 12 #include <linux/hugetlb.h> 13 #include <asm/fixmap.h> 14 #include <asm/code-patching.h> 15 #include <asm/inst.h> 16 17 #include <mm/mmu_decl.h> 18 19 #define IMMR_SIZE (FIX_IMMR_SIZE << PAGE_SHIFT) 20 21 extern int __map_without_ltlbs; 22 23 static unsigned long block_mapped_ram; 24 25 /* 26 * Return PA for this VA if it is in an area mapped with LTLBs or fixmap. 27 * Otherwise, returns 0 28 */ 29 phys_addr_t v_block_mapped(unsigned long va) 30 { 31 unsigned long p = PHYS_IMMR_BASE; 32 33 if (va >= VIRT_IMMR_BASE && va < VIRT_IMMR_BASE + IMMR_SIZE) 34 return p + va - VIRT_IMMR_BASE; 35 if (__map_without_ltlbs) 36 return 0; 37 if (va >= PAGE_OFFSET && va < PAGE_OFFSET + block_mapped_ram) 38 return __pa(va); 39 return 0; 40 } 41 42 /* 43 * Return VA for a given PA mapped with LTLBs or fixmap 44 * Return 0 if not mapped 45 */ 46 unsigned long p_block_mapped(phys_addr_t pa) 47 { 48 unsigned long p = PHYS_IMMR_BASE; 49 50 if (pa >= p && pa < p + IMMR_SIZE) 51 return VIRT_IMMR_BASE + pa - p; 52 if (__map_without_ltlbs) 53 return 0; 54 if (pa < block_mapped_ram) 55 return (unsigned long)__va(pa); 56 return 0; 57 } 58 59 static pte_t __init *early_hugepd_alloc_kernel(hugepd_t *pmdp, unsigned long va) 60 { 61 if (hpd_val(*pmdp) == 0) { 62 pte_t *ptep = memblock_alloc(sizeof(pte_basic_t), SZ_4K); 63 64 if (!ptep) 65 return NULL; 66 67 hugepd_populate_kernel((hugepd_t *)pmdp, ptep, PAGE_SHIFT_8M); 68 hugepd_populate_kernel((hugepd_t *)pmdp + 1, ptep, PAGE_SHIFT_8M); 69 } 70 return hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT); 71 } 72 73 static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa, 74 pgprot_t prot, int psize, bool new) 75 { 76 pmd_t *pmdp = pmd_off_k(va); 77 pte_t *ptep; 78 79 if (WARN_ON(psize != MMU_PAGE_512K && psize != MMU_PAGE_8M)) 80 return -EINVAL; 81 82 if (new) { 83 if (WARN_ON(slab_is_available())) 84 return -EINVAL; 85 86 if (psize == MMU_PAGE_512K) 87 ptep = early_pte_alloc_kernel(pmdp, va); 88 else 89 ptep = early_hugepd_alloc_kernel((hugepd_t *)pmdp, va); 90 } else { 91 if (psize == MMU_PAGE_512K) 92 ptep = pte_offset_kernel(pmdp, va); 93 else 94 ptep = hugepte_offset(*(hugepd_t *)pmdp, va, PGDIR_SHIFT); 95 } 96 97 if (WARN_ON(!ptep)) 98 return -ENOMEM; 99 100 /* The PTE should never be already present */ 101 if (new && WARN_ON(pte_present(*ptep) && pgprot_val(prot))) 102 return -EINVAL; 103 104 set_huge_pte_at(&init_mm, va, ptep, pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot))); 105 106 return 0; 107 } 108 109 /* 110 * MMU_init_hw does the chip-specific initialization of the MMU hardware. 111 */ 112 void __init MMU_init_hw(void) 113 { 114 } 115 116 static bool immr_is_mapped __initdata; 117 118 void __init mmu_mapin_immr(void) 119 { 120 if (immr_is_mapped) 121 return; 122 123 immr_is_mapped = true; 124 125 __early_map_kernel_hugepage(VIRT_IMMR_BASE, PHYS_IMMR_BASE, 126 PAGE_KERNEL_NCG, MMU_PAGE_512K, true); 127 } 128 129 static void mmu_mapin_ram_chunk(unsigned long offset, unsigned long top, 130 pgprot_t prot, bool new) 131 { 132 unsigned long v = PAGE_OFFSET + offset; 133 unsigned long p = offset; 134 135 WARN_ON(!IS_ALIGNED(offset, SZ_512K) || !IS_ALIGNED(top, SZ_512K)); 136 137 for (; p < ALIGN(p, SZ_8M) && p < top; p += SZ_512K, v += SZ_512K) 138 __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new); 139 for (; p < ALIGN_DOWN(top, SZ_8M) && p < top; p += SZ_8M, v += SZ_8M) 140 __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_8M, new); 141 for (; p < ALIGN_DOWN(top, SZ_512K) && p < top; p += SZ_512K, v += SZ_512K) 142 __early_map_kernel_hugepage(v, p, prot, MMU_PAGE_512K, new); 143 144 if (!new) 145 flush_tlb_kernel_range(PAGE_OFFSET + v, PAGE_OFFSET + top); 146 } 147 148 unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) 149 { 150 unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M); 151 unsigned long sinittext = __pa(_sinittext); 152 bool strict_boundary = strict_kernel_rwx_enabled() || debug_pagealloc_enabled(); 153 unsigned long boundary = strict_boundary ? sinittext : etext8; 154 unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M); 155 156 WARN_ON(top < einittext8); 157 158 mmu_mapin_immr(); 159 160 if (__map_without_ltlbs) 161 return 0; 162 163 mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, true); 164 if (debug_pagealloc_enabled()) { 165 top = boundary; 166 } else { 167 mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL_TEXT, true); 168 mmu_mapin_ram_chunk(einittext8, top, PAGE_KERNEL, true); 169 } 170 171 if (top > SZ_32M) 172 memblock_set_current_limit(top); 173 174 block_mapped_ram = top; 175 176 return top; 177 } 178 179 void mmu_mark_initmem_nx(void) 180 { 181 unsigned long etext8 = ALIGN(__pa(_etext), SZ_8M); 182 unsigned long sinittext = __pa(_sinittext); 183 unsigned long boundary = strict_kernel_rwx_enabled() ? sinittext : etext8; 184 unsigned long einittext8 = ALIGN(__pa(_einittext), SZ_8M); 185 186 mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, false); 187 mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false); 188 189 if (IS_ENABLED(CONFIG_PIN_TLB_TEXT)) 190 mmu_pin_tlb(block_mapped_ram, false); 191 } 192 193 #ifdef CONFIG_STRICT_KERNEL_RWX 194 void mmu_mark_rodata_ro(void) 195 { 196 unsigned long sinittext = __pa(_sinittext); 197 198 mmu_mapin_ram_chunk(0, sinittext, PAGE_KERNEL_ROX, false); 199 if (IS_ENABLED(CONFIG_PIN_TLB_DATA)) 200 mmu_pin_tlb(block_mapped_ram, true); 201 } 202 #endif 203 204 void __init setup_initial_memory_limit(phys_addr_t first_memblock_base, 205 phys_addr_t first_memblock_size) 206 { 207 /* We don't currently support the first MEMBLOCK not mapping 0 208 * physical on those processors 209 */ 210 BUG_ON(first_memblock_base != 0); 211 212 /* 8xx can only access 32MB at the moment */ 213 memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_32M)); 214 } 215 216 /* 217 * Set up to use a given MMU context. 218 * id is context number, pgd is PGD pointer. 219 * 220 * We place the physical address of the new task page directory loaded 221 * into the MMU base register, and set the ASID compare register with 222 * the new "context." 223 */ 224 void set_context(unsigned long id, pgd_t *pgd) 225 { 226 s16 offset = (s16)(__pa(swapper_pg_dir)); 227 228 /* Context switch the PTE pointer for the Abatron BDI2000. 229 * The PGDIR is passed as second argument. 230 */ 231 if (IS_ENABLED(CONFIG_BDI_SWITCH)) 232 abatron_pteptrs[1] = pgd; 233 234 /* Register M_TWB will contain base address of level 1 table minus the 235 * lower part of the kernel PGDIR base address, so that all accesses to 236 * level 1 table are done relative to lower part of kernel PGDIR base 237 * address. 238 */ 239 mtspr(SPRN_M_TWB, __pa(pgd) - offset); 240 241 /* Update context */ 242 mtspr(SPRN_M_CASID, id - 1); 243 /* sync */ 244 mb(); 245 } 246 247 #ifdef CONFIG_PPC_KUEP 248 void __init setup_kuep(bool disabled) 249 { 250 if (disabled) 251 return; 252 253 pr_info("Activating Kernel Userspace Execution Prevention\n"); 254 255 mtspr(SPRN_MI_AP, MI_APG_KUEP); 256 } 257 #endif 258 259 #ifdef CONFIG_PPC_KUAP 260 void __init setup_kuap(bool disabled) 261 { 262 pr_info("Activating Kernel Userspace Access Protection\n"); 263 264 if (disabled) 265 pr_warn("KUAP cannot be disabled yet on 8xx when compiled in\n"); 266 267 mtspr(SPRN_MD_AP, MD_APG_KUAP); 268 } 269 #endif 270