507 lines
12 KiB
C
507 lines
12 KiB
C
/*
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* Re-map IO memory to kernel address space so that we can access it.
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* This is needed for high PCI addresses that aren't mapped in the
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* 640k-1MB IO memory area on PC's
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*
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* (C) Copyright 1995 1996 Linus Torvalds
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*/
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#include <linux/bootmem.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/e820.h>
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#include <asm/fixmap.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/pgalloc.h>
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enum ioremap_mode {
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IOR_MODE_UNCACHED,
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IOR_MODE_CACHED,
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};
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#ifdef CONFIG_X86_64
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unsigned long __phys_addr(unsigned long x)
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{
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if (x >= __START_KERNEL_map)
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return x - __START_KERNEL_map + phys_base;
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return x - PAGE_OFFSET;
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}
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EXPORT_SYMBOL(__phys_addr);
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#endif
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int page_is_ram(unsigned long pagenr)
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{
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unsigned long addr, end;
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int i;
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/*
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* A special case is the first 4Kb of memory;
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* This is a BIOS owned area, not kernel ram, but generally
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* not listed as such in the E820 table.
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*/
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if (pagenr == 0)
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return 0;
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/*
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* Second special case: Some BIOSen report the PC BIOS
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* area (640->1Mb) as ram even though it is not.
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*/
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if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
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pagenr < (BIOS_END >> PAGE_SHIFT))
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return 0;
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for (i = 0; i < e820.nr_map; i++) {
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/*
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* Not usable memory:
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*/
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if (e820.map[i].type != E820_RAM)
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continue;
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addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
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end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
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if ((pagenr >= addr) && (pagenr < end))
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return 1;
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}
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return 0;
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}
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/*
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* Fix up the linear direct mapping of the kernel to avoid cache attribute
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* conflicts.
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*/
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static int ioremap_change_attr(unsigned long vaddr, unsigned long size,
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enum ioremap_mode mode)
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{
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unsigned long nrpages = size >> PAGE_SHIFT;
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int err;
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switch (mode) {
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case IOR_MODE_UNCACHED:
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default:
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err = set_memory_uc(vaddr, nrpages);
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break;
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case IOR_MODE_CACHED:
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err = set_memory_wb(vaddr, nrpages);
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break;
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}
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return err;
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}
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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*
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* NOTE! We need to allow non-page-aligned mappings too: we will obviously
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* have to convert them into an offset in a page-aligned mapping, but the
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* caller shouldn't need to know that small detail.
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*/
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static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size,
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enum ioremap_mode mode)
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{
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unsigned long pfn, offset, last_addr, vaddr;
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struct vm_struct *area;
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pgprot_t prot;
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/* Don't allow wraparound or zero size */
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last_addr = phys_addr + size - 1;
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if (!size || last_addr < phys_addr)
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return NULL;
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/*
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* Don't remap the low PCI/ISA area, it's always mapped..
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*/
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if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
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return (__force void __iomem *)phys_to_virt(phys_addr);
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/*
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* Don't allow anybody to remap normal RAM that we're using..
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*/
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for (pfn = phys_addr >> PAGE_SHIFT; pfn < max_pfn_mapped &&
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(pfn << PAGE_SHIFT) < last_addr; pfn++) {
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if (page_is_ram(pfn) && pfn_valid(pfn) &&
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!PageReserved(pfn_to_page(pfn)))
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return NULL;
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}
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switch (mode) {
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case IOR_MODE_UNCACHED:
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default:
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/*
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* FIXME: we will use UC MINUS for now, as video fb drivers
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* depend on it. Upcoming ioremap_wc() will fix this behavior.
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*/
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prot = PAGE_KERNEL_UC_MINUS;
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break;
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case IOR_MODE_CACHED:
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prot = PAGE_KERNEL;
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break;
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}
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/*
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* Mappings have to be page-aligned
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*/
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offset = phys_addr & ~PAGE_MASK;
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phys_addr &= PAGE_MASK;
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size = PAGE_ALIGN(last_addr+1) - phys_addr;
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/*
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* Ok, go for it..
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*/
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area = get_vm_area(size, VM_IOREMAP);
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if (!area)
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return NULL;
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area->phys_addr = phys_addr;
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vaddr = (unsigned long) area->addr;
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if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
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free_vm_area(area);
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return NULL;
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}
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if (ioremap_change_attr(vaddr, size, mode) < 0) {
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vunmap(area->addr);
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return NULL;
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}
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return (void __iomem *) (vaddr + offset);
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}
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/**
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* ioremap_nocache - map bus memory into CPU space
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* @offset: bus address of the memory
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* @size: size of the resource to map
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*
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* ioremap_nocache performs a platform specific sequence of operations to
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* make bus memory CPU accessible via the readb/readw/readl/writeb/
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* writew/writel functions and the other mmio helpers. The returned
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* address is not guaranteed to be usable directly as a virtual
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* address.
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*
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* This version of ioremap ensures that the memory is marked uncachable
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* on the CPU as well as honouring existing caching rules from things like
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* the PCI bus. Note that there are other caches and buffers on many
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* busses. In particular driver authors should read up on PCI writes
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*
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* It's useful if some control registers are in such an area and
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* write combining or read caching is not desirable:
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*
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* Must be freed with iounmap.
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*/
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void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
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{
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return __ioremap(phys_addr, size, IOR_MODE_UNCACHED);
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}
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EXPORT_SYMBOL(ioremap_nocache);
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void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
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{
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return __ioremap(phys_addr, size, IOR_MODE_CACHED);
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}
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EXPORT_SYMBOL(ioremap_cache);
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/**
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* iounmap - Free a IO remapping
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* @addr: virtual address from ioremap_*
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*
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* Caller must ensure there is only one unmapping for the same pointer.
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*/
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void iounmap(volatile void __iomem *addr)
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{
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struct vm_struct *p, *o;
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if ((void __force *)addr <= high_memory)
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return;
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/*
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* __ioremap special-cases the PCI/ISA range by not instantiating a
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* vm_area and by simply returning an address into the kernel mapping
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* of ISA space. So handle that here.
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*/
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if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
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addr < phys_to_virt(ISA_END_ADDRESS))
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return;
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addr = (volatile void __iomem *)
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(PAGE_MASK & (unsigned long __force)addr);
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/* Use the vm area unlocked, assuming the caller
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ensures there isn't another iounmap for the same address
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in parallel. Reuse of the virtual address is prevented by
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leaving it in the global lists until we're done with it.
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cpa takes care of the direct mappings. */
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read_lock(&vmlist_lock);
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for (p = vmlist; p; p = p->next) {
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if (p->addr == addr)
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break;
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}
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read_unlock(&vmlist_lock);
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if (!p) {
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printk(KERN_ERR "iounmap: bad address %p\n", addr);
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dump_stack();
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return;
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}
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/* Finally remove it */
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o = remove_vm_area((void *)addr);
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BUG_ON(p != o || o == NULL);
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kfree(p);
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}
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EXPORT_SYMBOL(iounmap);
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#ifdef CONFIG_X86_32
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int __initdata early_ioremap_debug;
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static int __init early_ioremap_debug_setup(char *str)
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{
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early_ioremap_debug = 1;
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return 0;
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}
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early_param("early_ioremap_debug", early_ioremap_debug_setup);
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static __initdata int after_paging_init;
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static __initdata pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)]
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__attribute__((aligned(PAGE_SIZE)));
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static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
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{
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/* Don't assume we're using swapper_pg_dir at this point */
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pgd_t *base = __va(read_cr3());
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pgd_t *pgd = &base[pgd_index(addr)];
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pud_t *pud = pud_offset(pgd, addr);
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pmd_t *pmd = pmd_offset(pud, addr);
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return pmd;
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}
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static inline pte_t * __init early_ioremap_pte(unsigned long addr)
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{
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return &bm_pte[pte_index(addr)];
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}
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void __init early_ioremap_init(void)
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{
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pmd_t *pmd;
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if (early_ioremap_debug)
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printk(KERN_INFO "early_ioremap_init()\n");
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pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
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memset(bm_pte, 0, sizeof(bm_pte));
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pmd_populate_kernel(&init_mm, pmd, bm_pte);
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/*
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* The boot-ioremap range spans multiple pmds, for which
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* we are not prepared:
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*/
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if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
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WARN_ON(1);
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printk(KERN_WARNING "pmd %p != %p\n",
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pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
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printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
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fix_to_virt(FIX_BTMAP_BEGIN));
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printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n",
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fix_to_virt(FIX_BTMAP_END));
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printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
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printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n",
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FIX_BTMAP_BEGIN);
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}
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}
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void __init early_ioremap_clear(void)
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{
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pmd_t *pmd;
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if (early_ioremap_debug)
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printk(KERN_INFO "early_ioremap_clear()\n");
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pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
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pmd_clear(pmd);
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paravirt_release_pt(__pa(bm_pte) >> PAGE_SHIFT);
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__flush_tlb_all();
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}
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void __init early_ioremap_reset(void)
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{
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enum fixed_addresses idx;
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unsigned long addr, phys;
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pte_t *pte;
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after_paging_init = 1;
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for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
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addr = fix_to_virt(idx);
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pte = early_ioremap_pte(addr);
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if (pte_present(*pte)) {
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phys = pte_val(*pte) & PAGE_MASK;
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set_fixmap(idx, phys);
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}
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}
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}
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static void __init __early_set_fixmap(enum fixed_addresses idx,
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unsigned long phys, pgprot_t flags)
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{
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unsigned long addr = __fix_to_virt(idx);
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pte_t *pte;
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if (idx >= __end_of_fixed_addresses) {
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BUG();
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return;
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}
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pte = early_ioremap_pte(addr);
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if (pgprot_val(flags))
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set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
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else
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pte_clear(NULL, addr, pte);
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__flush_tlb_one(addr);
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}
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static inline void __init early_set_fixmap(enum fixed_addresses idx,
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unsigned long phys)
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{
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if (after_paging_init)
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set_fixmap(idx, phys);
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else
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__early_set_fixmap(idx, phys, PAGE_KERNEL);
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}
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static inline void __init early_clear_fixmap(enum fixed_addresses idx)
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{
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if (after_paging_init)
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clear_fixmap(idx);
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else
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__early_set_fixmap(idx, 0, __pgprot(0));
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}
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int __initdata early_ioremap_nested;
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static int __init check_early_ioremap_leak(void)
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{
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if (!early_ioremap_nested)
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return 0;
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printk(KERN_WARNING
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"Debug warning: early ioremap leak of %d areas detected.\n",
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early_ioremap_nested);
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printk(KERN_WARNING
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"please boot with early_ioremap_debug and report the dmesg.\n");
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WARN_ON(1);
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return 1;
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}
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late_initcall(check_early_ioremap_leak);
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void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
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{
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unsigned long offset, last_addr;
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unsigned int nrpages, nesting;
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enum fixed_addresses idx0, idx;
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WARN_ON(system_state != SYSTEM_BOOTING);
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nesting = early_ioremap_nested;
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if (early_ioremap_debug) {
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printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
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phys_addr, size, nesting);
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dump_stack();
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}
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/* Don't allow wraparound or zero size */
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last_addr = phys_addr + size - 1;
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if (!size || last_addr < phys_addr) {
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WARN_ON(1);
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return NULL;
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}
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if (nesting >= FIX_BTMAPS_NESTING) {
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WARN_ON(1);
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return NULL;
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}
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early_ioremap_nested++;
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/*
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* Mappings have to be page-aligned
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*/
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offset = phys_addr & ~PAGE_MASK;
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phys_addr &= PAGE_MASK;
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size = PAGE_ALIGN(last_addr) - phys_addr;
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/*
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* Mappings have to fit in the FIX_BTMAP area.
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*/
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nrpages = size >> PAGE_SHIFT;
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if (nrpages > NR_FIX_BTMAPS) {
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WARN_ON(1);
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return NULL;
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}
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/*
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* Ok, go for it..
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*/
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idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
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idx = idx0;
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while (nrpages > 0) {
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early_set_fixmap(idx, phys_addr);
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phys_addr += PAGE_SIZE;
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--idx;
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--nrpages;
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}
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if (early_ioremap_debug)
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printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
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return (void *) (offset + fix_to_virt(idx0));
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}
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void __init early_iounmap(void *addr, unsigned long size)
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{
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unsigned long virt_addr;
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unsigned long offset;
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unsigned int nrpages;
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enum fixed_addresses idx;
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unsigned int nesting;
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nesting = --early_ioremap_nested;
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WARN_ON(nesting < 0);
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if (early_ioremap_debug) {
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printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
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size, nesting);
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dump_stack();
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}
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virt_addr = (unsigned long)addr;
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if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
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WARN_ON(1);
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return;
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}
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offset = virt_addr & ~PAGE_MASK;
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nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
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idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
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while (nrpages > 0) {
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early_clear_fixmap(idx);
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--idx;
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--nrpages;
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}
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}
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void __this_fixmap_does_not_exist(void)
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{
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WARN_ON(1);
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}
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#endif /* CONFIG_X86_32 */
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