2 * linux/arch/alpha/mm/init.c
4 * Copyright (C) 1995 Linus Torvalds
7 /* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */
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>
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>
25 #include <linux/uaccess.h>
26 #include <asm/pgtable.h>
27 #include <asm/pgalloc.h>
28 #include <asm/hwrpb.h>
30 #include <asm/mmu_context.h>
31 #include <asm/console.h>
33 #include <asm/setup.h>
34 #include <asm/sections.h>
36 extern void die_if_kernel(char *,struct pt_regs *,long);
38 static struct pcb_struct original_pcb;
41 pgd_alloc(struct mm_struct *mm)
45 ret = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
46 init = pgd_offset(&init_mm, 0UL);
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));
52 pgd_val(ret[PTRS_PER_PGD-2]) = pgd_val(init[PTRS_PER_PGD-2]);
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));
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
70 * BAD_PAGETABLE is the accompanying page-table: it is initialized
71 * to point to BAD_PAGE entries.
73 * ZERO_PAGE is a special page that is used for zero-initialized
79 memset((void *) EMPTY_PGT, 0, PAGE_SIZE);
80 return (pmd_t *) EMPTY_PGT;
86 memset((void *) EMPTY_PGE, 0, PAGE_SIZE);
87 return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED));
90 static inline unsigned long
91 load_PCB(struct pcb_struct *pcb)
93 register unsigned long sp __asm__("$30");
95 return __reload_thread(pcb);
98 /* Set up initial PCB, VPTB, and other such nicities. */
101 switch_to_system_map(void)
103 unsigned long newptbr;
104 unsigned long original_pcb_ptr;
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);
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);
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);
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.
130 Note that the PCB is supposed to be a physical address, but
131 since KSEG values also happen to work, folks get confused.
134 if (original_pcb_ptr < PAGE_OFFSET) {
135 original_pcb_ptr = (unsigned long)
136 phys_to_virt(original_pcb_ptr);
138 original_pcb = *(struct pcb_struct *) original_pcb_ptr;
141 int callback_init_done;
144 callback_init(void * kernel_end)
146 struct crb_struct * crb;
151 /* Starting at the HWRPB, locate the CRB. */
152 crb = (struct crb_struct *)((char *)hwrpb + hwrpb->crb_offset);
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 */
159 /* Edit the procedure descriptors for DISPATCH and FIXUP. */
160 crb->dispatch_va = (struct procdesc_struct *)
161 (VMALLOC_START + (unsigned long)crb->dispatch_va
163 crb->fixup_va = (struct procdesc_struct *)
164 (VMALLOC_START + (unsigned long)crb->fixup_va
168 switch_to_system_map();
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.
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. */
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);
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));
190 if (alpha_using_srm) {
191 static struct vm_struct console_remap_vm;
192 unsigned long nr_pages = 0;
196 /* calculate needed size */
197 for (i = 0; i < crb->map_entries; ++i)
198 nr_pages += crb->map[i].count;
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);
205 vaddr = (unsigned long)console_remap_vm.addr;
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;
222 set_pte(pte_offset_kernel(pmd, vaddr),
223 pfn_pte(pfn, PAGE_KERNEL));
230 callback_init_done = 1;
235 #ifndef CONFIG_DISCONTIGMEM
237 * paging_init() sets up the memory map.
239 void __init paging_init(void)
241 unsigned long zones_size[MAX_NR_ZONES] = {0, };
242 unsigned long dma_pfn, high_pfn;
244 dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
245 high_pfn = max_pfn = max_low_pfn;
247 if (dma_pfn >= high_pfn)
248 zones_size[ZONE_DMA] = high_pfn;
250 zones_size[ZONE_DMA] = dma_pfn;
251 zones_size[ZONE_NORMAL] = high_pfn - dma_pfn;
254 /* Initialize mem_map[]. */
255 free_area_init(zones_size);
257 /* Initialize the kernel's ZERO_PGE. */
258 memset((void *)ZERO_PGE, 0, PAGE_SIZE);
260 #endif /* CONFIG_DISCONTIGMEM */
262 #if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM)
264 srm_paging_stop (void)
266 /* Move the vptb back to where the SRM console expects it. */
267 swapper_pg_dir[1] = swapper_pg_dir[1023];
269 wrvptptr(0x200000000UL);
270 hwrpb->vptb = 0x200000000UL;
271 hwrpb_update_checksum(hwrpb);
273 /* Reload the page tables that the console had in use. */
274 load_PCB(&original_pcb);
282 set_max_mapnr(max_low_pfn);
283 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
285 mem_init_print_info(NULL);
291 free_initmem_default(-1);
294 #ifdef CONFIG_BLK_DEV_INITRD
296 free_initrd_mem(unsigned long start, unsigned long end)
298 free_reserved_area((void *)start, (void *)end, -1, "initrd");