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 #include <linux/gfp.h> 24 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 #include <asm/setup.h> 34 #include <asm/sections.h> 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 nr_pages = 0; 193 unsigned long vaddr; 194 unsigned long i, j; 195 196 /* calculate needed size */ 197 for (i = 0; i < crb->map_entries; ++i) 198 nr_pages += crb->map[i].count; 199 200 /* register the vm area */ 201 console_remap_vm.flags = VM_ALLOC; 202 console_remap_vm.size = nr_pages << PAGE_SHIFT; 203 vm_area_register_early(&console_remap_vm, PAGE_SIZE); 204 205 vaddr = (unsigned long)console_remap_vm.addr; 206 207 /* Set up the third level PTEs and update the virtual 208 addresses of the CRB entries. */ 209 for (i = 0; i < crb->map_entries; ++i) { 210 unsigned long pfn = crb->map[i].pa >> PAGE_SHIFT; 211 crb->map[i].va = vaddr; 212 for (j = 0; j < crb->map[i].count; ++j) { 213 /* Newer consoles (especially on larger 214 systems) may require more pages of 215 PTEs. Grab additional pages as needed. */ 216 if (pmd != pmd_offset(pgd, vaddr)) { 217 memset(kernel_end, 0, PAGE_SIZE); 218 pmd = pmd_offset(pgd, vaddr); 219 pmd_set(pmd, (pte_t *)kernel_end); 220 kernel_end += PAGE_SIZE; 221 } 222 set_pte(pte_offset_kernel(pmd, vaddr), 223 pfn_pte(pfn, PAGE_KERNEL)); 224 pfn++; 225 vaddr += PAGE_SIZE; 226 } 227 } 228 } 229 230 callback_init_done = 1; 231 return kernel_end; 232 } 233 234 235 #ifndef CONFIG_DISCONTIGMEM 236 /* 237 * paging_init() sets up the memory map. 238 */ 239 void __init paging_init(void) 240 { 241 unsigned long zones_size[MAX_NR_ZONES] = {0, }; 242 unsigned long dma_pfn, high_pfn; 243 244 dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT; 245 high_pfn = max_pfn = max_low_pfn; 246 247 if (dma_pfn >= high_pfn) 248 zones_size[ZONE_DMA] = high_pfn; 249 else { 250 zones_size[ZONE_DMA] = dma_pfn; 251 zones_size[ZONE_NORMAL] = high_pfn - dma_pfn; 252 } 253 254 /* Initialize mem_map[]. */ 255 free_area_init(zones_size); 256 257 /* Initialize the kernel's ZERO_PGE. */ 258 memset((void *)ZERO_PGE, 0, PAGE_SIZE); 259 } 260 #endif /* CONFIG_DISCONTIGMEM */ 261 262 #if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM) 263 void 264 srm_paging_stop (void) 265 { 266 /* Move the vptb back to where the SRM console expects it. */ 267 swapper_pg_dir[1] = swapper_pg_dir[1023]; 268 tbia(); 269 wrvptptr(0x200000000UL); 270 hwrpb->vptb = 0x200000000UL; 271 hwrpb_update_checksum(hwrpb); 272 273 /* Reload the page tables that the console had in use. */ 274 load_PCB(&original_pcb); 275 tbia(); 276 } 277 #endif 278 279 void __init 280 mem_init(void) 281 { 282 set_max_mapnr(max_low_pfn); 283 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE); 284 free_all_bootmem(); 285 mem_init_print_info(NULL); 286 } 287 288 void 289 free_initmem(void) 290 { 291 free_initmem_default(-1); 292 } 293 294 #ifdef CONFIG_BLK_DEV_INITRD 295 void 296 free_initrd_mem(unsigned long start, unsigned long end) 297 { 298 free_reserved_area((void *)start, (void *)end, -1, "initrd"); 299 } 300 #endif 301