1 /* 2 * linux/arch/alpha/mm/init.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 */ 6 7 /* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */ 8 9 #include <linux/pagemap.h> 10 #include <linux/signal.h> 11 #include <linux/sched.h> 12 #include <linux/kernel.h> 13 #include <linux/errno.h> 14 #include <linux/string.h> 15 #include <linux/types.h> 16 #include <linux/ptrace.h> 17 #include <linux/mman.h> 18 #include <linux/mm.h> 19 #include <linux/swap.h> 20 #include <linux/init.h> 21 #include <linux/bootmem.h> /* max_low_pfn */ 22 #include <linux/vmalloc.h> 23 24 #include <asm/system.h> 25 #include <asm/uaccess.h> 26 #include <asm/pgtable.h> 27 #include <asm/pgalloc.h> 28 #include <asm/hwrpb.h> 29 #include <asm/dma.h> 30 #include <asm/mmu_context.h> 31 #include <asm/console.h> 32 #include <asm/tlb.h> 33 34 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 35 36 extern void die_if_kernel(char *,struct pt_regs *,long); 37 38 static struct pcb_struct original_pcb; 39 40 pgd_t * 41 pgd_alloc(struct mm_struct *mm) 42 { 43 pgd_t *ret, *init; 44 45 ret = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO); 46 init = pgd_offset(&init_mm, 0UL); 47 if (ret) { 48 #ifdef CONFIG_ALPHA_LARGE_VMALLOC 49 memcpy (ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD, 50 (PTRS_PER_PGD - USER_PTRS_PER_PGD - 1)*sizeof(pgd_t)); 51 #else 52 pgd_val(ret[PTRS_PER_PGD-2]) = pgd_val(init[PTRS_PER_PGD-2]); 53 #endif 54 55 /* The last PGD entry is the VPTB self-map. */ 56 pgd_val(ret[PTRS_PER_PGD-1]) 57 = pte_val(mk_pte(virt_to_page(ret), PAGE_KERNEL)); 58 } 59 return ret; 60 } 61 62 63 /* 64 * BAD_PAGE is the page that is used for page faults when linux 65 * is out-of-memory. Older versions of linux just did a 66 * do_exit(), but using this instead means there is less risk 67 * for a process dying in kernel mode, possibly leaving an inode 68 * unused etc.. 69 * 70 * BAD_PAGETABLE is the accompanying page-table: it is initialized 71 * to point to BAD_PAGE entries. 72 * 73 * ZERO_PAGE is a special page that is used for zero-initialized 74 * data and COW. 75 */ 76 pmd_t * 77 __bad_pagetable(void) 78 { 79 memset((void *) EMPTY_PGT, 0, PAGE_SIZE); 80 return (pmd_t *) EMPTY_PGT; 81 } 82 83 pte_t 84 __bad_page(void) 85 { 86 memset((void *) EMPTY_PGE, 0, PAGE_SIZE); 87 return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED)); 88 } 89 90 static inline unsigned long 91 load_PCB(struct pcb_struct *pcb) 92 { 93 register unsigned long sp __asm__("$30"); 94 pcb->ksp = sp; 95 return __reload_thread(pcb); 96 } 97 98 /* Set up initial PCB, VPTB, and other such nicities. */ 99 100 static inline void 101 switch_to_system_map(void) 102 { 103 unsigned long newptbr; 104 unsigned long original_pcb_ptr; 105 106 /* Initialize the kernel's page tables. Linux puts the vptb in 107 the last slot of the L1 page table. */ 108 memset(swapper_pg_dir, 0, PAGE_SIZE); 109 newptbr = ((unsigned long) swapper_pg_dir - PAGE_OFFSET) >> PAGE_SHIFT; 110 pgd_val(swapper_pg_dir[1023]) = 111 (newptbr << 32) | pgprot_val(PAGE_KERNEL); 112 113 /* Set the vptb. This is often done by the bootloader, but 114 shouldn't be required. */ 115 if (hwrpb->vptb != 0xfffffffe00000000UL) { 116 wrvptptr(0xfffffffe00000000UL); 117 hwrpb->vptb = 0xfffffffe00000000UL; 118 hwrpb_update_checksum(hwrpb); 119 } 120 121 /* Also set up the real kernel PCB while we're at it. */ 122 init_thread_info.pcb.ptbr = newptbr; 123 init_thread_info.pcb.flags = 1; /* set FEN, clear everything else */ 124 original_pcb_ptr = load_PCB(&init_thread_info.pcb); 125 tbia(); 126 127 /* Save off the contents of the original PCB so that we can 128 restore the original console's page tables for a clean reboot. 129 130 Note that the PCB is supposed to be a physical address, but 131 since KSEG values also happen to work, folks get confused. 132 Check this here. */ 133 134 if (original_pcb_ptr < PAGE_OFFSET) { 135 original_pcb_ptr = (unsigned long) 136 phys_to_virt(original_pcb_ptr); 137 } 138 original_pcb = *(struct pcb_struct *) original_pcb_ptr; 139 } 140 141 int callback_init_done; 142 143 void * __init 144 callback_init(void * kernel_end) 145 { 146 struct crb_struct * crb; 147 pgd_t *pgd; 148 pmd_t *pmd; 149 void *two_pages; 150 151 /* Starting at the HWRPB, locate the CRB. */ 152 crb = (struct crb_struct *)((char *)hwrpb + hwrpb->crb_offset); 153 154 if (alpha_using_srm) { 155 /* Tell the console whither it is to be remapped. */ 156 if (srm_fixup(VMALLOC_START, (unsigned long)hwrpb)) 157 __halt(); /* "We're boned." --Bender */ 158 159 /* Edit the procedure descriptors for DISPATCH and FIXUP. */ 160 crb->dispatch_va = (struct procdesc_struct *) 161 (VMALLOC_START + (unsigned long)crb->dispatch_va 162 - crb->map[0].va); 163 crb->fixup_va = (struct procdesc_struct *) 164 (VMALLOC_START + (unsigned long)crb->fixup_va 165 - crb->map[0].va); 166 } 167 168 switch_to_system_map(); 169 170 /* Allocate one PGD and one PMD. In the case of SRM, we'll need 171 these to actually remap the console. There is an assumption 172 here that only one of each is needed, and this allows for 8MB. 173 On systems with larger consoles, additional pages will be 174 allocated as needed during the mapping process. 175 176 In the case of not SRM, but not CONFIG_ALPHA_LARGE_VMALLOC, 177 we need to allocate the PGD we use for vmalloc before we start 178 forking other tasks. */ 179 180 two_pages = (void *) 181 (((unsigned long)kernel_end + ~PAGE_MASK) & PAGE_MASK); 182 kernel_end = two_pages + 2*PAGE_SIZE; 183 memset(two_pages, 0, 2*PAGE_SIZE); 184 185 pgd = pgd_offset_k(VMALLOC_START); 186 pgd_set(pgd, (pmd_t *)two_pages); 187 pmd = pmd_offset(pgd, VMALLOC_START); 188 pmd_set(pmd, (pte_t *)(two_pages + PAGE_SIZE)); 189 190 if (alpha_using_srm) { 191 static struct vm_struct console_remap_vm; 192 unsigned long vaddr = VMALLOC_START; 193 unsigned long i, j; 194 195 /* Set up the third level PTEs and update the virtual 196 addresses of the CRB entries. */ 197 for (i = 0; i < crb->map_entries; ++i) { 198 unsigned long pfn = crb->map[i].pa >> PAGE_SHIFT; 199 crb->map[i].va = vaddr; 200 for (j = 0; j < crb->map[i].count; ++j) { 201 /* Newer consoles (especially on larger 202 systems) may require more pages of 203 PTEs. Grab additional pages as needed. */ 204 if (pmd != pmd_offset(pgd, vaddr)) { 205 memset(kernel_end, 0, PAGE_SIZE); 206 pmd = pmd_offset(pgd, vaddr); 207 pmd_set(pmd, (pte_t *)kernel_end); 208 kernel_end += PAGE_SIZE; 209 } 210 set_pte(pte_offset_kernel(pmd, vaddr), 211 pfn_pte(pfn, PAGE_KERNEL)); 212 pfn++; 213 vaddr += PAGE_SIZE; 214 } 215 } 216 217 /* Let vmalloc know that we've allocated some space. */ 218 console_remap_vm.flags = VM_ALLOC; 219 console_remap_vm.addr = (void *) VMALLOC_START; 220 console_remap_vm.size = vaddr - VMALLOC_START; 221 vmlist = &console_remap_vm; 222 } 223 224 callback_init_done = 1; 225 return kernel_end; 226 } 227 228 229 #ifndef CONFIG_DISCONTIGMEM 230 /* 231 * paging_init() sets up the memory map. 232 */ 233 void __init paging_init(void) 234 { 235 unsigned long zones_size[MAX_NR_ZONES] = {0, }; 236 unsigned long dma_pfn, high_pfn; 237 238 dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT; 239 high_pfn = max_pfn = max_low_pfn; 240 241 if (dma_pfn >= high_pfn) 242 zones_size[ZONE_DMA] = high_pfn; 243 else { 244 zones_size[ZONE_DMA] = dma_pfn; 245 zones_size[ZONE_NORMAL] = high_pfn - dma_pfn; 246 } 247 248 /* Initialize mem_map[]. */ 249 free_area_init(zones_size); 250 251 /* Initialize the kernel's ZERO_PGE. */ 252 memset((void *)ZERO_PGE, 0, PAGE_SIZE); 253 } 254 #endif /* CONFIG_DISCONTIGMEM */ 255 256 #if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM) 257 void 258 srm_paging_stop (void) 259 { 260 /* Move the vptb back to where the SRM console expects it. */ 261 swapper_pg_dir[1] = swapper_pg_dir[1023]; 262 tbia(); 263 wrvptptr(0x200000000UL); 264 hwrpb->vptb = 0x200000000UL; 265 hwrpb_update_checksum(hwrpb); 266 267 /* Reload the page tables that the console had in use. */ 268 load_PCB(&original_pcb); 269 tbia(); 270 } 271 #endif 272 273 #ifndef CONFIG_DISCONTIGMEM 274 static void __init 275 printk_memory_info(void) 276 { 277 unsigned long codesize, reservedpages, datasize, initsize, tmp; 278 extern int page_is_ram(unsigned long) __init; 279 extern char _text, _etext, _data, _edata; 280 extern char __init_begin, __init_end; 281 282 /* printk all informations */ 283 reservedpages = 0; 284 for (tmp = 0; tmp < max_low_pfn; tmp++) 285 /* 286 * Only count reserved RAM pages 287 */ 288 if (page_is_ram(tmp) && PageReserved(mem_map+tmp)) 289 reservedpages++; 290 291 codesize = (unsigned long) &_etext - (unsigned long) &_text; 292 datasize = (unsigned long) &_edata - (unsigned long) &_data; 293 initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin; 294 295 printk("Memory: %luk/%luk available (%luk kernel code, %luk reserved, %luk data, %luk init)\n", 296 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10), 297 max_mapnr << (PAGE_SHIFT-10), 298 codesize >> 10, 299 reservedpages << (PAGE_SHIFT-10), 300 datasize >> 10, 301 initsize >> 10); 302 } 303 304 void __init 305 mem_init(void) 306 { 307 max_mapnr = num_physpages = max_low_pfn; 308 totalram_pages += free_all_bootmem(); 309 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE); 310 311 printk_memory_info(); 312 } 313 #endif /* CONFIG_DISCONTIGMEM */ 314 315 void 316 free_reserved_mem(void *start, void *end) 317 { 318 void *__start = start; 319 for (; __start < end; __start += PAGE_SIZE) { 320 ClearPageReserved(virt_to_page(__start)); 321 init_page_count(virt_to_page(__start)); 322 free_page((long)__start); 323 totalram_pages++; 324 } 325 } 326 327 void 328 free_initmem(void) 329 { 330 extern char __init_begin, __init_end; 331 332 free_reserved_mem(&__init_begin, &__init_end); 333 printk ("Freeing unused kernel memory: %ldk freed\n", 334 (&__init_end - &__init_begin) >> 10); 335 } 336 337 #ifdef CONFIG_BLK_DEV_INITRD 338 void 339 free_initrd_mem(unsigned long start, unsigned long end) 340 { 341 free_reserved_mem((void *)start, (void *)end); 342 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10); 343 } 344 #endif 345