1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/arch/alpha/mm/init.c 4 * 5 * Copyright (C) 1995 Linus Torvalds 6 */ 7 8 /* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */ 9 10 #include <linux/pagemap.h> 11 #include <linux/signal.h> 12 #include <linux/sched.h> 13 #include <linux/kernel.h> 14 #include <linux/errno.h> 15 #include <linux/string.h> 16 #include <linux/types.h> 17 #include <linux/ptrace.h> 18 #include <linux/mman.h> 19 #include <linux/mm.h> 20 #include <linux/swap.h> 21 #include <linux/init.h> 22 #include <linux/memblock.h> /* max_low_pfn */ 23 #include <linux/vmalloc.h> 24 #include <linux/gfp.h> 25 26 #include <linux/uaccess.h> 27 #include <asm/pgtable.h> 28 #include <asm/pgalloc.h> 29 #include <asm/hwrpb.h> 30 #include <asm/dma.h> 31 #include <asm/mmu_context.h> 32 #include <asm/console.h> 33 #include <asm/tlb.h> 34 #include <asm/setup.h> 35 #include <asm/sections.h> 36 37 extern void die_if_kernel(char *,struct pt_regs *,long); 38 39 static struct pcb_struct original_pcb; 40 41 pgd_t * 42 pgd_alloc(struct mm_struct *mm) 43 { 44 pgd_t *ret, *init; 45 46 ret = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 47 init = pgd_offset(&init_mm, 0UL); 48 if (ret) { 49 #ifdef CONFIG_ALPHA_LARGE_VMALLOC 50 memcpy (ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD, 51 (PTRS_PER_PGD - USER_PTRS_PER_PGD - 1)*sizeof(pgd_t)); 52 #else 53 pgd_val(ret[PTRS_PER_PGD-2]) = pgd_val(init[PTRS_PER_PGD-2]); 54 #endif 55 56 /* The last PGD entry is the VPTB self-map. */ 57 pgd_val(ret[PTRS_PER_PGD-1]) 58 = pte_val(mk_pte(virt_to_page(ret), PAGE_KERNEL)); 59 } 60 return ret; 61 } 62 63 64 /* 65 * BAD_PAGE is the page that is used for page faults when linux 66 * is out-of-memory. Older versions of linux just did a 67 * do_exit(), but using this instead means there is less risk 68 * for a process dying in kernel mode, possibly leaving an inode 69 * unused etc.. 70 * 71 * BAD_PAGETABLE is the accompanying page-table: it is initialized 72 * to point to BAD_PAGE entries. 73 * 74 * ZERO_PAGE is a special page that is used for zero-initialized 75 * data and COW. 76 */ 77 pmd_t * 78 __bad_pagetable(void) 79 { 80 memset((void *) EMPTY_PGT, 0, PAGE_SIZE); 81 return (pmd_t *) EMPTY_PGT; 82 } 83 84 pte_t 85 __bad_page(void) 86 { 87 memset((void *) EMPTY_PGE, 0, PAGE_SIZE); 88 return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED)); 89 } 90 91 static inline unsigned long 92 load_PCB(struct pcb_struct *pcb) 93 { 94 register unsigned long sp __asm__("$30"); 95 pcb->ksp = sp; 96 return __reload_thread(pcb); 97 } 98 99 /* Set up initial PCB, VPTB, and other such nicities. */ 100 101 static inline void 102 switch_to_system_map(void) 103 { 104 unsigned long newptbr; 105 unsigned long original_pcb_ptr; 106 107 /* Initialize the kernel's page tables. Linux puts the vptb in 108 the last slot of the L1 page table. */ 109 memset(swapper_pg_dir, 0, PAGE_SIZE); 110 newptbr = ((unsigned long) swapper_pg_dir - PAGE_OFFSET) >> PAGE_SHIFT; 111 pgd_val(swapper_pg_dir[1023]) = 112 (newptbr << 32) | pgprot_val(PAGE_KERNEL); 113 114 /* Set the vptb. This is often done by the bootloader, but 115 shouldn't be required. */ 116 if (hwrpb->vptb != 0xfffffffe00000000UL) { 117 wrvptptr(0xfffffffe00000000UL); 118 hwrpb->vptb = 0xfffffffe00000000UL; 119 hwrpb_update_checksum(hwrpb); 120 } 121 122 /* Also set up the real kernel PCB while we're at it. */ 123 init_thread_info.pcb.ptbr = newptbr; 124 init_thread_info.pcb.flags = 1; /* set FEN, clear everything else */ 125 original_pcb_ptr = load_PCB(&init_thread_info.pcb); 126 tbia(); 127 128 /* Save off the contents of the original PCB so that we can 129 restore the original console's page tables for a clean reboot. 130 131 Note that the PCB is supposed to be a physical address, but 132 since KSEG values also happen to work, folks get confused. 133 Check this here. */ 134 135 if (original_pcb_ptr < PAGE_OFFSET) { 136 original_pcb_ptr = (unsigned long) 137 phys_to_virt(original_pcb_ptr); 138 } 139 original_pcb = *(struct pcb_struct *) original_pcb_ptr; 140 } 141 142 int callback_init_done; 143 144 void * __init 145 callback_init(void * kernel_end) 146 { 147 struct crb_struct * crb; 148 pgd_t *pgd; 149 pmd_t *pmd; 150 void *two_pages; 151 152 /* Starting at the HWRPB, locate the CRB. */ 153 crb = (struct crb_struct *)((char *)hwrpb + hwrpb->crb_offset); 154 155 if (alpha_using_srm) { 156 /* Tell the console whither it is to be remapped. */ 157 if (srm_fixup(VMALLOC_START, (unsigned long)hwrpb)) 158 __halt(); /* "We're boned." --Bender */ 159 160 /* Edit the procedure descriptors for DISPATCH and FIXUP. */ 161 crb->dispatch_va = (struct procdesc_struct *) 162 (VMALLOC_START + (unsigned long)crb->dispatch_va 163 - crb->map[0].va); 164 crb->fixup_va = (struct procdesc_struct *) 165 (VMALLOC_START + (unsigned long)crb->fixup_va 166 - crb->map[0].va); 167 } 168 169 switch_to_system_map(); 170 171 /* Allocate one PGD and one PMD. In the case of SRM, we'll need 172 these to actually remap the console. There is an assumption 173 here that only one of each is needed, and this allows for 8MB. 174 On systems with larger consoles, additional pages will be 175 allocated as needed during the mapping process. 176 177 In the case of not SRM, but not CONFIG_ALPHA_LARGE_VMALLOC, 178 we need to allocate the PGD we use for vmalloc before we start 179 forking other tasks. */ 180 181 two_pages = (void *) 182 (((unsigned long)kernel_end + ~PAGE_MASK) & PAGE_MASK); 183 kernel_end = two_pages + 2*PAGE_SIZE; 184 memset(two_pages, 0, 2*PAGE_SIZE); 185 186 pgd = pgd_offset_k(VMALLOC_START); 187 pgd_set(pgd, (pmd_t *)two_pages); 188 pmd = pmd_offset(pgd, VMALLOC_START); 189 pmd_set(pmd, (pte_t *)(two_pages + PAGE_SIZE)); 190 191 if (alpha_using_srm) { 192 static struct vm_struct console_remap_vm; 193 unsigned long nr_pages = 0; 194 unsigned long vaddr; 195 unsigned long i, j; 196 197 /* calculate needed size */ 198 for (i = 0; i < crb->map_entries; ++i) 199 nr_pages += crb->map[i].count; 200 201 /* register the vm area */ 202 console_remap_vm.flags = VM_ALLOC; 203 console_remap_vm.size = nr_pages << PAGE_SHIFT; 204 vm_area_register_early(&console_remap_vm, PAGE_SIZE); 205 206 vaddr = (unsigned long)console_remap_vm.addr; 207 208 /* Set up the third level PTEs and update the virtual 209 addresses of the CRB entries. */ 210 for (i = 0; i < crb->map_entries; ++i) { 211 unsigned long pfn = crb->map[i].pa >> PAGE_SHIFT; 212 crb->map[i].va = vaddr; 213 for (j = 0; j < crb->map[i].count; ++j) { 214 /* Newer consoles (especially on larger 215 systems) may require more pages of 216 PTEs. Grab additional pages as needed. */ 217 if (pmd != pmd_offset(pgd, vaddr)) { 218 memset(kernel_end, 0, PAGE_SIZE); 219 pmd = pmd_offset(pgd, vaddr); 220 pmd_set(pmd, (pte_t *)kernel_end); 221 kernel_end += PAGE_SIZE; 222 } 223 set_pte(pte_offset_kernel(pmd, vaddr), 224 pfn_pte(pfn, PAGE_KERNEL)); 225 pfn++; 226 vaddr += PAGE_SIZE; 227 } 228 } 229 } 230 231 callback_init_done = 1; 232 return kernel_end; 233 } 234 235 236 #ifndef CONFIG_DISCONTIGMEM 237 /* 238 * paging_init() sets up the memory map. 239 */ 240 void __init paging_init(void) 241 { 242 unsigned long zones_size[MAX_NR_ZONES] = {0, }; 243 unsigned long dma_pfn, high_pfn; 244 245 dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT; 246 high_pfn = max_pfn = max_low_pfn; 247 248 if (dma_pfn >= high_pfn) 249 zones_size[ZONE_DMA] = high_pfn; 250 else { 251 zones_size[ZONE_DMA] = dma_pfn; 252 zones_size[ZONE_NORMAL] = high_pfn - dma_pfn; 253 } 254 255 /* Initialize mem_map[]. */ 256 free_area_init(zones_size); 257 258 /* Initialize the kernel's ZERO_PGE. */ 259 memset((void *)ZERO_PGE, 0, PAGE_SIZE); 260 } 261 #endif /* CONFIG_DISCONTIGMEM */ 262 263 #if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM) 264 void 265 srm_paging_stop (void) 266 { 267 /* Move the vptb back to where the SRM console expects it. */ 268 swapper_pg_dir[1] = swapper_pg_dir[1023]; 269 tbia(); 270 wrvptptr(0x200000000UL); 271 hwrpb->vptb = 0x200000000UL; 272 hwrpb_update_checksum(hwrpb); 273 274 /* Reload the page tables that the console had in use. */ 275 load_PCB(&original_pcb); 276 tbia(); 277 } 278 #endif 279 280 void __init 281 mem_init(void) 282 { 283 set_max_mapnr(max_low_pfn); 284 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE); 285 memblock_free_all(); 286 mem_init_print_info(NULL); 287 } 288 289 void 290 free_initmem(void) 291 { 292 free_initmem_default(-1); 293 } 294 295 #ifdef CONFIG_BLK_DEV_INITRD 296 void 297 free_initrd_mem(unsigned long start, unsigned long end) 298 { 299 free_reserved_area((void *)start, (void *)end, -1, "initrd"); 300 } 301 #endif 302