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286 lines
6.8 KiB
C
286 lines
6.8 KiB
C
/*
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* This file contains the routines setting up the linux page tables.
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*
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* Copyright (C) 2008 Michal Simek
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* Copyright (C) 2008 PetaLogix
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*
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* Copyright (C) 2007 Xilinx, Inc. All rights reserved.
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*
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* Derived from arch/ppc/mm/pgtable.c:
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* -- paulus
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*
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* Derived from arch/ppc/mm/init.c:
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* This file is subject to the terms and conditions of the GNU General
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* Public License. See the file COPYING in the main directory of this
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* archive for more details.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <linux/io.h>
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#include <asm/mmu.h>
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#include <asm/sections.h>
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#define flush_HPTE(X, va, pg) _tlbie(va)
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unsigned long ioremap_base;
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unsigned long ioremap_bot;
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/* The maximum lowmem defaults to 768Mb, but this can be configured to
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* another value.
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*/
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#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
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#ifndef CONFIG_SMP
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struct pgtable_cache_struct quicklists;
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#endif
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static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
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unsigned long flags)
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{
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unsigned long v, i;
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phys_addr_t p;
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int err;
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/*
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* Choose an address to map it to.
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* Once the vmalloc system is running, we use it.
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* Before then, we use space going down from ioremap_base
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* (ioremap_bot records where we're up to).
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*/
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p = addr & PAGE_MASK;
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size = PAGE_ALIGN(addr + size) - p;
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/*
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* Don't allow anybody to remap normal RAM that we're using.
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* mem_init() sets high_memory so only do the check after that.
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*
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* However, allow remap of rootfs: TBD
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*/
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if (mem_init_done &&
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p >= memory_start && p < virt_to_phys(high_memory) &&
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!(p >= virt_to_phys((unsigned long)&__bss_stop) &&
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p < virt_to_phys((unsigned long)__bss_stop))) {
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printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT
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" is RAM lr %p\n", (unsigned long)p,
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__builtin_return_address(0));
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return NULL;
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}
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if (size == 0)
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return NULL;
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/*
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* Is it already mapped? If the whole area is mapped then we're
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* done, otherwise remap it since we want to keep the virt addrs for
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* each request contiguous.
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*
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* We make the assumption here that if the bottom and top
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* of the range we want are mapped then it's mapped to the
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* same virt address (and this is contiguous).
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* -- Cort
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*/
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if (mem_init_done) {
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struct vm_struct *area;
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area = get_vm_area(size, VM_IOREMAP);
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if (area == NULL)
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return NULL;
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v = VMALLOC_VMADDR(area->addr);
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} else {
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v = (ioremap_bot -= size);
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}
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if ((flags & _PAGE_PRESENT) == 0)
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flags |= _PAGE_KERNEL;
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if (flags & _PAGE_NO_CACHE)
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flags |= _PAGE_GUARDED;
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err = 0;
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for (i = 0; i < size && err == 0; i += PAGE_SIZE)
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err = map_page(v + i, p + i, flags);
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if (err) {
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if (mem_init_done)
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vfree((void *)v);
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return NULL;
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}
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return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
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}
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void __iomem *ioremap(phys_addr_t addr, unsigned long size)
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{
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return __ioremap(addr, size, _PAGE_NO_CACHE);
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}
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EXPORT_SYMBOL(ioremap);
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void iounmap(void *addr)
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{
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if (addr > high_memory && (unsigned long) addr < ioremap_bot)
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vfree((void *) (PAGE_MASK & (unsigned long) addr));
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}
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EXPORT_SYMBOL(iounmap);
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int map_page(unsigned long va, phys_addr_t pa, int flags)
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{
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pmd_t *pd;
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pte_t *pg;
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int err = -ENOMEM;
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/* spin_lock(&init_mm.page_table_lock); */
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/* Use upper 10 bits of VA to index the first level map */
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pd = pmd_offset(pgd_offset_k(va), va);
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/* Use middle 10 bits of VA to index the second-level map */
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pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
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/* pg = pte_alloc_kernel(&init_mm, pd, va); */
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if (pg != NULL) {
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err = 0;
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set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
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__pgprot(flags)));
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if (mem_init_done)
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flush_HPTE(0, va, pmd_val(*pd));
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/* flush_HPTE(0, va, pg); */
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}
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/* spin_unlock(&init_mm.page_table_lock); */
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return err;
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}
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void __init adjust_total_lowmem(void)
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{
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/* TBD */
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#if 0
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unsigned long max_low_mem = MAX_LOW_MEM;
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if (total_lowmem > max_low_mem) {
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total_lowmem = max_low_mem;
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#ifndef CONFIG_HIGHMEM
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printk(KERN_INFO "Warning, memory limited to %ld Mb, use "
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"CONFIG_HIGHMEM to reach %ld Mb\n",
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max_low_mem >> 20, total_memory >> 20);
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total_memory = total_lowmem;
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#endif /* CONFIG_HIGHMEM */
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}
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#endif
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}
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static void show_tmem(unsigned long tmem)
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{
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volatile unsigned long a;
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a = a + tmem;
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}
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/*
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* Map in all of physical memory starting at CONFIG_KERNEL_START.
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*/
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void __init mapin_ram(void)
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{
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unsigned long v, p, s, f;
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v = CONFIG_KERNEL_START;
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p = memory_start;
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show_tmem(memory_size);
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for (s = 0; s < memory_size; s += PAGE_SIZE) {
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f = _PAGE_PRESENT | _PAGE_ACCESSED |
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_PAGE_SHARED | _PAGE_HWEXEC;
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if ((char *) v < _stext || (char *) v >= _etext)
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f |= _PAGE_WRENABLE;
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else
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/* On the MicroBlaze, no user access
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forces R/W kernel access */
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f |= _PAGE_USER;
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map_page(v, p, f);
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v += PAGE_SIZE;
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p += PAGE_SIZE;
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}
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}
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/* is x a power of 2? */
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#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
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/*
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* Set up a mapping for a block of I/O.
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* virt, phys, size must all be page-aligned.
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* This should only be called before ioremap is called.
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*/
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void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
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unsigned int size, int flags)
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{
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int i;
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if (virt > CONFIG_KERNEL_START && virt < ioremap_bot)
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ioremap_bot = ioremap_base = virt;
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/* Put it in the page tables. */
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for (i = 0; i < size; i += PAGE_SIZE)
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map_page(virt + i, phys + i, flags);
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}
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/* Scan the real Linux page tables and return a PTE pointer for
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* a virtual address in a context.
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* Returns true (1) if PTE was found, zero otherwise. The pointer to
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* the PTE pointer is unmodified if PTE is not found.
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*/
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static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
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{
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pgd_t *pgd;
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pmd_t *pmd;
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pte_t *pte;
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int retval = 0;
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pgd = pgd_offset(mm, addr & PAGE_MASK);
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if (pgd) {
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pmd = pmd_offset(pgd, addr & PAGE_MASK);
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if (pmd_present(*pmd)) {
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pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
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if (pte) {
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retval = 1;
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*ptep = pte;
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}
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}
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}
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return retval;
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}
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/* Find physical address for this virtual address. Normally used by
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* I/O functions, but anyone can call it.
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*/
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unsigned long iopa(unsigned long addr)
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{
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unsigned long pa;
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pte_t *pte;
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struct mm_struct *mm;
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/* Allow mapping of user addresses (within the thread)
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* for DMA if necessary.
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*/
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if (addr < TASK_SIZE)
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mm = current->mm;
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else
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mm = &init_mm;
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pa = 0;
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if (get_pteptr(mm, addr, &pte))
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pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
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return pa;
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}
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