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 pte = (pte_t *)early_get_page();
98 struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address)
102 #ifdef CONFIG_HIGHPTE
103 int flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_REPEAT;
105 int flags = GFP_KERNEL | __GFP_REPEAT;
108 pte = alloc_pages(flags, 0);
114 void pte_free_kernel(pte_t *pte)
119 free_page((unsigned long)pte);
122 void pte_free(struct page *pte)
132 ioremap(phys_addr_t addr, unsigned long size)
134 return __ioremap(addr, size, _PAGE_NO_CACHE);
136 #else /* CONFIG_44x */
138 ioremap64(unsigned long long addr, unsigned long size)
140 return __ioremap(addr, size, _PAGE_NO_CACHE);
144 ioremap(phys_addr_t addr, unsigned long size)
146 phys_addr_t addr64 = fixup_bigphys_addr(addr, size);
148 return ioremap64(addr64, size);
150 #endif /* CONFIG_44x */
153 __ioremap(phys_addr_t addr, unsigned long size, unsigned long flags)
160 * Choose an address to map it to.
161 * Once the vmalloc system is running, we use it.
162 * Before then, we use space going down from ioremap_base
163 * (ioremap_bot records where we're up to).
165 p = addr & PAGE_MASK;
166 size = PAGE_ALIGN(addr + size) - p;
169 * If the address lies within the first 16 MB, assume it's in ISA
172 if (p < 16*1024*1024)
176 * Don't allow anybody to remap normal RAM that we're using.
177 * mem_init() sets high_memory so only do the check after that.
179 if ( mem_init_done && (p < virt_to_phys(high_memory)) )
181 printk("__ioremap(): phys addr "PTE_FMT" is RAM lr %p\n", p,
182 __builtin_return_address(0));
190 * Is it already mapped? Perhaps overlapped by a previous
191 * BAT mapping. If the whole area is mapped then we're done,
192 * otherwise remap it since we want to keep the virt addrs for
193 * each request contiguous.
195 * We make the assumption here that if the bottom and top
196 * of the range we want are mapped then it's mapped to the
197 * same virt address (and this is contiguous).
200 if ((v = p_mapped_by_bats(p)) /*&& p_mapped_by_bats(p+size-1)*/ )
204 struct vm_struct *area;
205 area = get_vm_area(size, VM_IOREMAP);
208 v = (unsigned long) area->addr;
210 v = (ioremap_bot -= size);
213 if ((flags & _PAGE_PRESENT) == 0)
214 flags |= _PAGE_KERNEL;
215 if (flags & _PAGE_NO_CACHE)
216 flags |= _PAGE_GUARDED;
219 * Should check if it is a candidate for a BAT mapping
223 for (i = 0; i < size && err == 0; i += PAGE_SIZE)
224 err = map_page(v+i, p+i, flags);
232 return (void *) (v + ((unsigned long)addr & ~PAGE_MASK));
235 void iounmap(void *addr)
238 * If mapped by BATs then there is nothing to do.
239 * Calling vfree() generates a benign warning.
241 if (v_mapped_by_bats((unsigned long)addr)) return;
243 if (addr > high_memory && (unsigned long) addr < ioremap_bot)
244 vunmap((void *) (PAGE_MASK & (unsigned long)addr));
248 map_page(unsigned long va, phys_addr_t pa, int flags)
254 spin_lock(&init_mm.page_table_lock);
255 /* Use upper 10 bits of VA to index the first level map */
256 pd = pmd_offset(pgd_offset_k(va), va);
257 /* Use middle 10 bits of VA to index the second-level map */
258 pg = pte_alloc_kernel(&init_mm, pd, va);
261 set_pte(pg, pfn_pte(pa >> PAGE_SHIFT, __pgprot(flags)));
263 flush_HPTE(0, va, pmd_val(*pd));
265 spin_unlock(&init_mm.page_table_lock);
270 * Map in all of physical memory starting at KERNELBASE.
272 void __init mapin_ram(void)
274 unsigned long v, p, s, f;
278 p = PPC_MEMSTART + s;
279 for (; s < total_lowmem; s += PAGE_SIZE) {
280 if ((char *) v >= _stext && (char *) v < etext)
290 /* is x a power of 2? */
291 #define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
294 * Set up a mapping for a block of I/O.
295 * virt, phys, size must all be page-aligned.
296 * This should only be called before ioremap is called.
298 void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
299 unsigned int size, int flags)
303 if (virt > KERNELBASE && virt < ioremap_bot)
304 ioremap_bot = ioremap_base = virt;
308 * Use a BAT for this if possible...
310 if (io_bat_index < 2 && is_power_of_2(size)
311 && (virt & (size - 1)) == 0 && (phys & (size - 1)) == 0) {
312 setbat(io_bat_index, virt, phys, size, flags);
316 #endif /* HAVE_BATS */
318 /* No BATs available, put it in the page tables. */
319 for (i = 0; i < size; i += PAGE_SIZE)
320 map_page(virt + i, phys + i, flags);
323 /* Scan the real Linux page tables and return a PTE pointer for
324 * a virtual address in a context.
325 * Returns true (1) if PTE was found, zero otherwise. The pointer to
326 * the PTE pointer is unmodified if PTE is not found.
329 get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
336 pgd = pgd_offset(mm, addr & PAGE_MASK);
338 pmd = pmd_offset(pgd, addr & PAGE_MASK);
339 if (pmd_present(*pmd)) {
340 pte = pte_offset_map(pmd, addr & PAGE_MASK);
344 /* XXX caller needs to do pte_unmap, yuck */
351 /* Find physical address for this virtual address. Normally used by
352 * I/O functions, but anyone can call it.
354 unsigned long iopa(unsigned long addr)
358 /* I don't know why this won't work on PMacs or CHRP. It
359 * appears there is some bug, or there is some implicit
360 * mapping done not properly represented by BATs or in page
361 * tables.......I am actively working on resolving this, but
362 * can't hold up other stuff. -- Dan
365 struct mm_struct *mm;
368 pa = v_mapped_by_bats(addr);
372 /* Allow mapping of user addresses (within the thread)
373 * for DMA if necessary.
375 if (addr < TASK_SIZE)
381 if (get_pteptr(mm, addr, &pte)) {
382 pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
389 /* This is will find the virtual address for a physical one....
390 * Swiped from APUS, could be dangerous :-).
391 * This is only a placeholder until I really find a way to make this
395 mm_ptov (unsigned long paddr)
399 if (paddr < 16*1024*1024)
400 ret = ZTWO_VADDR(paddr);
404 for (i = 0; i < kmap_chunk_count;){
405 unsigned long phys = kmap_chunks[i++];
406 unsigned long size = kmap_chunks[i++];
407 unsigned long virt = kmap_chunks[i++];
409 && paddr < (phys + size)){
410 ret = virt + paddr - phys;
415 ret = (unsigned long) __va(paddr);
419 printk ("PTOV(%lx)=%lx\n", paddr, ret);
422 ret = (unsigned long)paddr + KERNELBASE;