2 * This file contains the routines setting up the linux page tables.
5 * Derived from arch/ppc/mm/init.c:
6 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
8 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
9 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
10 * Copyright (C) 1996 Paul Mackerras
11 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
13 * Derived from "arch/i386/mm/init.c"
14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
16 * This program is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU General Public License
18 * as published by the Free Software Foundation; either version
19 * 2 of the License, or (at your option) any later version.
23 #include <linux/config.h>
24 #include <linux/kernel.h>
25 #include <linux/types.h>
27 #include <linux/vmalloc.h>
28 #include <linux/init.h>
29 #include <linux/highmem.h>
31 #include <asm/pgtable.h>
32 #include <asm/pgalloc.h>
37 unsigned long ioremap_base;
38 unsigned long ioremap_bot;
41 #if defined(CONFIG_6xx) || defined(CONFIG_POWER3)
45 extern char etext[], _stext[];
48 extern void hash_page_sync(void);
52 extern unsigned long v_mapped_by_bats(unsigned long va);
53 extern unsigned long p_mapped_by_bats(unsigned long pa);
54 void setbat(int index, unsigned long virt, unsigned long phys,
55 unsigned int size, int flags);
57 #else /* !HAVE_BATS */
58 #define v_mapped_by_bats(x) (0UL)
59 #define p_mapped_by_bats(x) (0UL)
60 #endif /* HAVE_BATS */
63 /* 44x uses an 8kB pgdir because it has 8-byte Linux PTEs. */
69 pgd_t *pgd_alloc(struct mm_struct *mm)
73 if ((ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGDIR_ORDER)) != NULL)
74 clear_pages(ret, PGDIR_ORDER);
78 void pgd_free(pgd_t *pgd)
80 free_pages((unsigned long)pgd, PGDIR_ORDER);
83 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
86 extern int mem_init_done;
87 extern void *early_get_page(void);
90 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
92 struct page *ptepage = virt_to_page(pte);
93 ptepage->mapping = (void *) mm;
94 ptepage->index = address & PMD_MASK;
97 pte = (pte_t *)early_get_page();
103 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
105 struct page *ptepage;
107 #ifdef CONFIG_HIGHPTE
108 int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
110 int flags = GFP_KERNEL | __GFP_REPEAT;
113 ptepage = alloc_pages(flags, 0);
115 ptepage->mapping = (void *) mm;
116 ptepage->index = address & PMD_MASK;
117 clear_highpage(ptepage);
122 void pte_free_kernel(pte_t *pte)
127 virt_to_page(pte)->mapping = NULL;
128 free_page((unsigned long)pte);
131 void pte_free(struct page *ptepage)
136 ptepage->mapping = NULL;
137 __free_page(ptepage);
142 ioremap(phys_addr_t addr, unsigned long size)
144 return __ioremap(addr, size, _PAGE_NO_CACHE);
146 #else /* CONFIG_44x */
148 ioremap64(unsigned long long addr, unsigned long size)
150 return __ioremap(addr, size, _PAGE_NO_CACHE);
154 ioremap(phys_addr_t addr, unsigned long size)
156 phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
158 return ioremap64(addr64, size);
160 #endif /* CONFIG_44x */
163 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
170 * Choose an address to map it to.
171 * Once the vmalloc system is running, we use it.
172 * Before then, we use space going down from ioremap_base
173 * (ioremap_bot records where we're up to).
175 p = addr & PAGE_MASK;
176 size = PAGE_ALIGN(addr + size) - p;
179 * If the address lies within the first 16 MB, assume it's in ISA
182 if (p < 16*1024*1024)
186 * Don't allow anybody to remap normal RAM that we're using.
187 * mem_init() sets high_memory so only do the check after that.
189 if ( mem_init_done && (p < virt_to_phys(high_memory)) )
191 printk("__ioremap(): phys addr "PTE_FMT" is RAM lr %p\n", p,
192 __builtin_return_address(0));
200 * Is it already mapped? Perhaps overlapped by a previous
201 * BAT mapping. If the whole area is mapped then we're done,
202 * otherwise remap it since we want to keep the virt addrs for
203 * each request contiguous.
205 * We make the assumption here that if the bottom and top
206 * of the range we want are mapped then it's mapped to the
207 * same virt address (and this is contiguous).
210 if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
214 struct vm_struct *area;
215 area = get_vm_area(size, VM_IOREMAP);
218 v = (unsigned long) area->addr;
220 v = (ioremap_bot -= size);
223 if ((flags & _PAGE_PRESENT) == 0)
224 flags |= _PAGE_KERNEL;
225 if (flags & _PAGE_NO_CACHE)
226 flags |= _PAGE_GUARDED;
229 * Should check if it is a candidate for a BAT mapping
233 for (i = 0; i < size && err == 0; i += PAGE_SIZE)
234 err = map_page(v+i, p+i, flags);
242 return (void *) (v + ((unsigned long)addr & ~PAGE_MASK));
245 void iounmap(void *addr)
248 * If mapped by BATs then there is nothing to do.
249 * Calling vfree() generates a benign warning.
251 if (v_mapped_by_bats((unsigned long)addr)) return;
253 if (addr > high_memory && (unsigned long) addr < ioremap_bot)
254 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
258 map_page(unsigned long va, phys_addr_t pa, int flags)
264 spin_lock(&init_mm.page_table_lock);
265 /* Use upper 10 bits of VA to index the first level map */
266 pd = pmd_offset(pgd_offset_k(va), va);
267 /* Use middle 10 bits of VA to index the second-level map */
268 pg = pte_alloc_kernel(&init_mm, pd, va);
271 set_pte(pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
273 flush_HPTE(0, va, pmd_val(*pd));
275 spin_unlock(&init_mm.page_table_lock);
280 * Map in all of physical memory starting at KERNELBASE.
282 void __init mapin_ram(void)
284 unsigned long v, p, s, f;
288 p = PPC_MEMSTART + s;
289 for (; s < total_lowmem; s += PAGE_SIZE) {
290 if ((char *) v >= _stext && (char *) v < etext)
300 /* is x a power of 2? */
301 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
304 * Set up a mapping for a block of I/O.
305 * virt, phys, size must all be page-aligned.
306 * This should only be called before ioremap is called.
308 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
309 unsigned int size, int flags)
313 if (virt > KERNELBASE && virt < ioremap_bot)
314 ioremap_bot = ioremap_base = virt;
318 * Use a BAT for this if possible...
320 if (io_bat_index < 2 && is_power_of_2(size)
321 && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
322 setbat(io_bat_index, virt, phys, size, flags);
326 #endif /* HAVE_BATS */
328 /* No BATs available, put it in the page tables. */
329 for (i = 0; i < size; i += PAGE_SIZE)
330 map_page(virt + i, phys + i, flags);
333 /* Scan the real Linux page tables and return a PTE pointer for
334 * a virtual address in a context.
335 * Returns true (1) if PTE was found, zero otherwise. The pointer to
336 * the PTE pointer is unmodified if PTE is not found.
339 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
346 pgd = pgd_offset(mm, addr & PAGE_MASK);
348 pmd = pmd_offset(pgd, addr & PAGE_MASK);
349 if (pmd_present(*pmd)) {
350 pte = pte_offset_map(pmd, addr & PAGE_MASK);
354 /* XXX caller needs to do pte_unmap, yuck */
361 /* Find physical address for this virtual address. Normally used by
362 * I/O functions, but anyone can call it.
364 unsigned long iopa(unsigned long addr)
368 /* I don't know why this won't work on PMacs or CHRP. It
369 * appears there is some bug, or there is some implicit
370 * mapping done not properly represented by BATs or in page
371 * tables.......I am actively working on resolving this, but
372 * can't hold up other stuff. -- Dan
375 struct mm_struct *mm;
378 pa = v_mapped_by_bats(addr);
382 /* Allow mapping of user addresses (within the thread)
383 * for DMA if necessary.
385 if (addr < TASK_SIZE)
391 if (get_pteptr(mm, addr, &pte)) {
392 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
399 /* This is will find the virtual address for a physical one....
400 * Swiped from APUS, could be dangerous :-).
401 * This is only a placeholder until I really find a way to make this
405 mm_ptov (unsigned long paddr)
409 if (paddr < 16*1024*1024)
410 ret = ZTWO_VADDR(paddr);
414 for (i = 0; i < kmap_chunk_count;){
415 unsigned long phys = kmap_chunks[i++];
416 unsigned long size = kmap_chunks[i++];
417 unsigned long virt = kmap_chunks[i++];
419 && paddr < (phys + size)){
420 ret = virt + paddr - phys;
425 ret = (unsigned long) __va(paddr);
429 printk ("PTOV(%lx)=%lx\n", paddr, ret);
432 ret = (unsigned long)paddr + KERNELBASE;