589 строки
13 KiB
C
589 строки
13 KiB
C
/*
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* linux/mm/vmalloc.c
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*
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* Copyright (C) 1993 Linus Torvalds
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* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
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* SMP-safe vmalloc/vfree/ioremap, Tigran Aivazian <tigran@veritas.com>, May 2000
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* Major rework to support vmap/vunmap, Christoph Hellwig, SGI, August 2002
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <linux/vmalloc.h>
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#include <asm/uaccess.h>
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#include <asm/tlbflush.h>
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DEFINE_RWLOCK(vmlist_lock);
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struct vm_struct *vmlist;
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static void vunmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end)
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{
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pte_t *pte;
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pte = pte_offset_kernel(pmd, addr);
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do {
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pte_t ptent = ptep_get_and_clear(&init_mm, addr, pte);
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WARN_ON(!pte_none(ptent) && !pte_present(ptent));
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} while (pte++, addr += PAGE_SIZE, addr != end);
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}
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static inline void vunmap_pmd_range(pud_t *pud, unsigned long addr,
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unsigned long end)
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{
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pmd_t *pmd;
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unsigned long next;
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pmd = pmd_offset(pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_none_or_clear_bad(pmd))
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continue;
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vunmap_pte_range(pmd, addr, next);
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} while (pmd++, addr = next, addr != end);
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}
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static inline void vunmap_pud_range(pgd_t *pgd, unsigned long addr,
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unsigned long end)
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{
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pud_t *pud;
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unsigned long next;
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pud = pud_offset(pgd, addr);
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do {
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next = pud_addr_end(addr, end);
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if (pud_none_or_clear_bad(pud))
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continue;
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vunmap_pmd_range(pud, addr, next);
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} while (pud++, addr = next, addr != end);
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}
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void unmap_vm_area(struct vm_struct *area)
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{
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pgd_t *pgd;
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unsigned long next;
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unsigned long addr = (unsigned long) area->addr;
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unsigned long end = addr + area->size;
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BUG_ON(addr >= end);
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pgd = pgd_offset_k(addr);
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flush_cache_vunmap(addr, end);
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do {
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next = pgd_addr_end(addr, end);
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if (pgd_none_or_clear_bad(pgd))
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continue;
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vunmap_pud_range(pgd, addr, next);
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} while (pgd++, addr = next, addr != end);
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flush_tlb_kernel_range((unsigned long) area->addr, end);
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}
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static int vmap_pte_range(pmd_t *pmd, unsigned long addr,
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unsigned long end, pgprot_t prot, struct page ***pages)
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{
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pte_t *pte;
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pte = pte_alloc_kernel(&init_mm, pmd, addr);
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if (!pte)
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return -ENOMEM;
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do {
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struct page *page = **pages;
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WARN_ON(!pte_none(*pte));
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if (!page)
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return -ENOMEM;
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set_pte_at(&init_mm, addr, pte, mk_pte(page, prot));
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(*pages)++;
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} while (pte++, addr += PAGE_SIZE, addr != end);
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return 0;
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}
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static inline int vmap_pmd_range(pud_t *pud, unsigned long addr,
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unsigned long end, pgprot_t prot, struct page ***pages)
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{
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pmd_t *pmd;
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unsigned long next;
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pmd = pmd_alloc(&init_mm, pud, addr);
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if (!pmd)
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return -ENOMEM;
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do {
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next = pmd_addr_end(addr, end);
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if (vmap_pte_range(pmd, addr, next, prot, pages))
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return -ENOMEM;
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} while (pmd++, addr = next, addr != end);
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return 0;
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}
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static inline int vmap_pud_range(pgd_t *pgd, unsigned long addr,
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unsigned long end, pgprot_t prot, struct page ***pages)
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{
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pud_t *pud;
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unsigned long next;
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pud = pud_alloc(&init_mm, pgd, addr);
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if (!pud)
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return -ENOMEM;
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do {
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next = pud_addr_end(addr, end);
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if (vmap_pmd_range(pud, addr, next, prot, pages))
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return -ENOMEM;
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} while (pud++, addr = next, addr != end);
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return 0;
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}
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int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
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{
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pgd_t *pgd;
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unsigned long next;
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unsigned long addr = (unsigned long) area->addr;
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unsigned long end = addr + area->size - PAGE_SIZE;
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int err;
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BUG_ON(addr >= end);
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pgd = pgd_offset_k(addr);
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spin_lock(&init_mm.page_table_lock);
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do {
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next = pgd_addr_end(addr, end);
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err = vmap_pud_range(pgd, addr, next, prot, pages);
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if (err)
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break;
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} while (pgd++, addr = next, addr != end);
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spin_unlock(&init_mm.page_table_lock);
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flush_cache_vmap((unsigned long) area->addr, end);
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return err;
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}
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#define IOREMAP_MAX_ORDER (7 + PAGE_SHIFT) /* 128 pages */
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struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
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unsigned long start, unsigned long end)
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{
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struct vm_struct **p, *tmp, *area;
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unsigned long align = 1;
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unsigned long addr;
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if (flags & VM_IOREMAP) {
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int bit = fls(size);
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if (bit > IOREMAP_MAX_ORDER)
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bit = IOREMAP_MAX_ORDER;
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else if (bit < PAGE_SHIFT)
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bit = PAGE_SHIFT;
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align = 1ul << bit;
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}
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addr = ALIGN(start, align);
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size = PAGE_ALIGN(size);
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area = kmalloc(sizeof(*area), GFP_KERNEL);
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if (unlikely(!area))
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return NULL;
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if (unlikely(!size)) {
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kfree (area);
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return NULL;
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}
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/*
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* We always allocate a guard page.
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*/
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size += PAGE_SIZE;
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write_lock(&vmlist_lock);
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for (p = &vmlist; (tmp = *p) != NULL ;p = &tmp->next) {
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if ((unsigned long)tmp->addr < addr) {
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if((unsigned long)tmp->addr + tmp->size >= addr)
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addr = ALIGN(tmp->size +
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(unsigned long)tmp->addr, align);
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continue;
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}
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if ((size + addr) < addr)
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goto out;
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if (size + addr <= (unsigned long)tmp->addr)
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goto found;
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addr = ALIGN(tmp->size + (unsigned long)tmp->addr, align);
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if (addr > end - size)
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goto out;
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}
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found:
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area->next = *p;
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*p = area;
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area->flags = flags;
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area->addr = (void *)addr;
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area->size = size;
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area->pages = NULL;
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area->nr_pages = 0;
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area->phys_addr = 0;
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write_unlock(&vmlist_lock);
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return area;
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out:
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write_unlock(&vmlist_lock);
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kfree(area);
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if (printk_ratelimit())
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printk(KERN_WARNING "allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.\n");
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return NULL;
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}
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/**
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* get_vm_area - reserve a contingous kernel virtual area
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*
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* @size: size of the area
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* @flags: %VM_IOREMAP for I/O mappings or VM_ALLOC
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*
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* Search an area of @size in the kernel virtual mapping area,
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* and reserved it for out purposes. Returns the area descriptor
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* on success or %NULL on failure.
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*/
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struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
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{
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return __get_vm_area(size, flags, VMALLOC_START, VMALLOC_END);
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}
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/**
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* remove_vm_area - find and remove a contingous kernel virtual area
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*
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* @addr: base address
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*
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* Search for the kernel VM area starting at @addr, and remove it.
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* This function returns the found VM area, but using it is NOT safe
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* on SMP machines.
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*/
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struct vm_struct *remove_vm_area(void *addr)
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{
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struct vm_struct **p, *tmp;
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write_lock(&vmlist_lock);
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for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) {
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if (tmp->addr == addr)
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goto found;
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}
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write_unlock(&vmlist_lock);
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return NULL;
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found:
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unmap_vm_area(tmp);
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*p = tmp->next;
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write_unlock(&vmlist_lock);
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/*
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* Remove the guard page.
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*/
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tmp->size -= PAGE_SIZE;
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return tmp;
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}
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void __vunmap(void *addr, int deallocate_pages)
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{
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struct vm_struct *area;
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if (!addr)
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return;
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if ((PAGE_SIZE-1) & (unsigned long)addr) {
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printk(KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
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WARN_ON(1);
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return;
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}
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area = remove_vm_area(addr);
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if (unlikely(!area)) {
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printk(KERN_ERR "Trying to vfree() nonexistent vm area (%p)\n",
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addr);
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WARN_ON(1);
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return;
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}
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if (deallocate_pages) {
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int i;
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for (i = 0; i < area->nr_pages; i++) {
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if (unlikely(!area->pages[i]))
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BUG();
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__free_page(area->pages[i]);
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}
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if (area->nr_pages > PAGE_SIZE/sizeof(struct page *))
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vfree(area->pages);
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else
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kfree(area->pages);
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}
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kfree(area);
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return;
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}
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/**
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* vfree - release memory allocated by vmalloc()
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*
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* @addr: memory base address
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*
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* Free the virtually contiguous memory area starting at @addr, as
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* obtained from vmalloc(), vmalloc_32() or __vmalloc().
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*
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* May not be called in interrupt context.
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*/
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void vfree(void *addr)
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{
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BUG_ON(in_interrupt());
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__vunmap(addr, 1);
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}
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EXPORT_SYMBOL(vfree);
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/**
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* vunmap - release virtual mapping obtained by vmap()
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*
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* @addr: memory base address
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*
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* Free the virtually contiguous memory area starting at @addr,
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* which was created from the page array passed to vmap().
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*
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* May not be called in interrupt context.
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*/
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void vunmap(void *addr)
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{
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BUG_ON(in_interrupt());
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__vunmap(addr, 0);
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}
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EXPORT_SYMBOL(vunmap);
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/**
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* vmap - map an array of pages into virtually contiguous space
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*
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* @pages: array of page pointers
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* @count: number of pages to map
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* @flags: vm_area->flags
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* @prot: page protection for the mapping
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*
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* Maps @count pages from @pages into contiguous kernel virtual
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* space.
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*/
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void *vmap(struct page **pages, unsigned int count,
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unsigned long flags, pgprot_t prot)
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{
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struct vm_struct *area;
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if (count > num_physpages)
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return NULL;
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area = get_vm_area((count << PAGE_SHIFT), flags);
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if (!area)
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return NULL;
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if (map_vm_area(area, prot, &pages)) {
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vunmap(area->addr);
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return NULL;
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}
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return area->addr;
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}
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EXPORT_SYMBOL(vmap);
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void *__vmalloc_area(struct vm_struct *area, unsigned int __nocast gfp_mask, pgprot_t prot)
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{
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struct page **pages;
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unsigned int nr_pages, array_size, i;
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nr_pages = (area->size - PAGE_SIZE) >> PAGE_SHIFT;
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array_size = (nr_pages * sizeof(struct page *));
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area->nr_pages = nr_pages;
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/* Please note that the recursion is strictly bounded. */
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if (array_size > PAGE_SIZE)
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pages = __vmalloc(array_size, gfp_mask, PAGE_KERNEL);
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else
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pages = kmalloc(array_size, (gfp_mask & ~__GFP_HIGHMEM));
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area->pages = pages;
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if (!area->pages) {
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remove_vm_area(area->addr);
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kfree(area);
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return NULL;
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}
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memset(area->pages, 0, array_size);
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for (i = 0; i < area->nr_pages; i++) {
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area->pages[i] = alloc_page(gfp_mask);
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if (unlikely(!area->pages[i])) {
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/* Successfully allocated i pages, free them in __vunmap() */
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area->nr_pages = i;
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goto fail;
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}
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}
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if (map_vm_area(area, prot, &pages))
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goto fail;
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return area->addr;
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fail:
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vfree(area->addr);
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return NULL;
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}
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/**
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* __vmalloc - allocate virtually contiguous memory
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*
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* @size: allocation size
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* @gfp_mask: flags for the page level allocator
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* @prot: protection mask for the allocated pages
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*
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* Allocate enough pages to cover @size from the page level
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* allocator with @gfp_mask flags. Map them into contiguous
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* kernel virtual space, using a pagetable protection of @prot.
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*/
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void *__vmalloc(unsigned long size, unsigned int __nocast gfp_mask, pgprot_t prot)
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{
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struct vm_struct *area;
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size = PAGE_ALIGN(size);
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if (!size || (size >> PAGE_SHIFT) > num_physpages)
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return NULL;
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area = get_vm_area(size, VM_ALLOC);
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if (!area)
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return NULL;
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return __vmalloc_area(area, gfp_mask, prot);
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}
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EXPORT_SYMBOL(__vmalloc);
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/**
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* vmalloc - allocate virtually contiguous memory
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*
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* @size: allocation size
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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*
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* For tight cotrol over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vmalloc(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
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}
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EXPORT_SYMBOL(vmalloc);
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/**
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* vmalloc_exec - allocate virtually contiguous, executable memory
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*
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* @size: allocation size
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*
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* Kernel-internal function to allocate enough pages to cover @size
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* the page level allocator and map them into contiguous and
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* executable kernel virtual space.
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*
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* For tight cotrol over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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#ifndef PAGE_KERNEL_EXEC
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# define PAGE_KERNEL_EXEC PAGE_KERNEL
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#endif
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void *vmalloc_exec(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
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}
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/**
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* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
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*
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* @size: allocation size
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*
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* Allocate enough 32bit PA addressable pages to cover @size from the
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* page level allocator and map them into contiguous kernel virtual space.
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*/
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void *vmalloc_32(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
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}
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EXPORT_SYMBOL(vmalloc_32);
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long vread(char *buf, char *addr, unsigned long count)
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{
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struct vm_struct *tmp;
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char *vaddr, *buf_start = buf;
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unsigned long n;
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/* Don't allow overflow */
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if ((unsigned long) addr + count < count)
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count = -(unsigned long) addr;
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read_lock(&vmlist_lock);
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for (tmp = vmlist; tmp; tmp = tmp->next) {
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vaddr = (char *) tmp->addr;
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if (addr >= vaddr + tmp->size - PAGE_SIZE)
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continue;
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while (addr < vaddr) {
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if (count == 0)
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goto finished;
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*buf = '\0';
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buf++;
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addr++;
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count--;
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}
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n = vaddr + tmp->size - PAGE_SIZE - addr;
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do {
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if (count == 0)
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goto finished;
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*buf = *addr;
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buf++;
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addr++;
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count--;
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} while (--n > 0);
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}
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finished:
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read_unlock(&vmlist_lock);
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return buf - buf_start;
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}
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|
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long vwrite(char *buf, char *addr, unsigned long count)
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{
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struct vm_struct *tmp;
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char *vaddr, *buf_start = buf;
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unsigned long n;
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|
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/* Don't allow overflow */
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if ((unsigned long) addr + count < count)
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count = -(unsigned long) addr;
|
|
|
|
read_lock(&vmlist_lock);
|
|
for (tmp = vmlist; tmp; tmp = tmp->next) {
|
|
vaddr = (char *) tmp->addr;
|
|
if (addr >= vaddr + tmp->size - PAGE_SIZE)
|
|
continue;
|
|
while (addr < vaddr) {
|
|
if (count == 0)
|
|
goto finished;
|
|
buf++;
|
|
addr++;
|
|
count--;
|
|
}
|
|
n = vaddr + tmp->size - PAGE_SIZE - addr;
|
|
do {
|
|
if (count == 0)
|
|
goto finished;
|
|
*addr = *buf;
|
|
buf++;
|
|
addr++;
|
|
count--;
|
|
} while (--n > 0);
|
|
}
|
|
finished:
|
|
read_unlock(&vmlist_lock);
|
|
return buf - buf_start;
|
|
}
|