240 lines
6.2 KiB
C
240 lines
6.2 KiB
C
/*
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* arch/sh/mm/ioremap.c
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*
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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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* (C) Copyright 2005, 2006 Paul Mundt
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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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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/pci.h>
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#include <asm/io.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/addrspace.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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static inline void remap_area_pte(pte_t * pte, unsigned long address,
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unsigned long size, unsigned long phys_addr, unsigned long flags)
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{
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unsigned long end;
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unsigned long pfn;
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pgprot_t pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW |
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_PAGE_DIRTY | _PAGE_ACCESSED |
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_PAGE_HW_SHARED | _PAGE_FLAGS_HARD | flags);
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address &= ~PMD_MASK;
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end = address + size;
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if (end > PMD_SIZE)
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end = PMD_SIZE;
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if (address >= end)
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BUG();
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pfn = phys_addr >> PAGE_SHIFT;
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do {
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if (!pte_none(*pte)) {
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printk("remap_area_pte: page already exists\n");
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BUG();
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}
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set_pte(pte, pfn_pte(pfn, pgprot));
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address += PAGE_SIZE;
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pfn++;
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pte++;
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} while (address && (address < end));
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}
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static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
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unsigned long size, unsigned long phys_addr, unsigned long flags)
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{
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unsigned long end;
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address &= ~PGDIR_MASK;
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end = address + size;
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if (end > PGDIR_SIZE)
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end = PGDIR_SIZE;
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phys_addr -= address;
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if (address >= end)
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BUG();
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do {
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pte_t * pte = pte_alloc_kernel(pmd, address);
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if (!pte)
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return -ENOMEM;
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remap_area_pte(pte, address, end - address, address + phys_addr, flags);
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address = (address + PMD_SIZE) & PMD_MASK;
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pmd++;
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} while (address && (address < end));
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return 0;
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}
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int remap_area_pages(unsigned long address, unsigned long phys_addr,
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unsigned long size, unsigned long flags)
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{
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int error;
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pgd_t * dir;
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unsigned long end = address + size;
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phys_addr -= address;
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dir = pgd_offset_k(address);
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flush_cache_all();
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if (address >= end)
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BUG();
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do {
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pud_t *pud;
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pmd_t *pmd;
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error = -ENOMEM;
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pud = pud_alloc(&init_mm, dir, address);
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if (!pud)
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break;
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pmd = pmd_alloc(&init_mm, pud, address);
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if (!pmd)
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break;
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if (remap_area_pmd(pmd, address, end - address,
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phys_addr + address, flags))
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break;
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error = 0;
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address = (address + PGDIR_SIZE) & PGDIR_MASK;
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dir++;
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} while (address && (address < end));
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flush_tlb_all();
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return error;
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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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void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
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unsigned long flags)
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{
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struct vm_struct * area;
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unsigned long offset, last_addr, addr, orig_addr;
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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 >= 0xA0000 && last_addr < 0x100000)
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return (void __iomem *)phys_to_virt(phys_addr);
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/*
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* If we're on an SH7751 or SH7780 PCI controller, PCI memory is
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* mapped at the end of the address space (typically 0xfd000000)
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* in a non-translatable area, so mapping through page tables for
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* this area is not only pointless, but also fundamentally
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* broken. Just return the physical address instead.
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*
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* For boards that map a small PCI memory aperture somewhere in
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* P1/P2 space, ioremap() will already do the right thing,
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* and we'll never get this far.
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*/
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if (is_pci_memaddr(phys_addr) && is_pci_memaddr(last_addr))
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return (void __iomem *)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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if (phys_addr < virt_to_phys(high_memory))
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return NULL;
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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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orig_addr = addr = (unsigned long)area->addr;
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#ifdef CONFIG_32BIT
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/*
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* First try to remap through the PMB once a valid VMA has been
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* established. Smaller allocations (or the rest of the size
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* remaining after a PMB mapping due to the size not being
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* perfectly aligned on a PMB size boundary) are then mapped
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* through the UTLB using conventional page tables.
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*
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* PMB entries are all pre-faulted.
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*/
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if (unlikely(size >= 0x1000000)) {
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unsigned long mapped = pmb_remap(addr, phys_addr, size, flags);
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if (likely(mapped)) {
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addr += mapped;
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phys_addr += mapped;
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size -= mapped;
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}
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}
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#endif
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if (likely(size))
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if (remap_area_pages(addr, phys_addr, size, flags)) {
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vunmap((void *)orig_addr);
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return NULL;
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}
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return (void __iomem *)(offset + (char *)orig_addr);
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}
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EXPORT_SYMBOL(__ioremap);
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void __iounmap(void __iomem *addr)
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{
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unsigned long vaddr = (unsigned long __force)addr;
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struct vm_struct *p;
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if (PXSEG(vaddr) < P3SEG || is_pci_memaddr(vaddr))
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return;
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#ifdef CONFIG_32BIT
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/*
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* Purge any PMB entries that may have been established for this
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* mapping, then proceed with conventional VMA teardown.
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*
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* XXX: Note that due to the way that remove_vm_area() does
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* matching of the resultant VMA, we aren't able to fast-forward
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* the address past the PMB space until the end of the VMA where
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* the page tables reside. As such, unmap_vm_area() will be
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* forced to linearly scan over the area until it finds the page
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* tables where PTEs that need to be unmapped actually reside,
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* which is far from optimal. Perhaps we need to use a separate
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* VMA for the PMB mappings?
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* -- PFM.
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*/
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pmb_unmap(vaddr);
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#endif
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p = remove_vm_area((void *)(vaddr & PAGE_MASK));
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if (!p) {
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printk(KERN_ERR "%s: bad address %p\n", __FUNCTION__, addr);
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return;
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}
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kfree(p);
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}
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EXPORT_SYMBOL(__iounmap);
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