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183ff22bb6
Spelling fixes in mm/. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: Adrian Bunk <bunk@kernel.org>
826 lines
19 KiB
C
826 lines
19 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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* Numa awareness, Christoph Lameter, SGI, June 2005
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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 *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
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int node);
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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_kernel_range(unsigned long addr, unsigned long size)
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{
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pgd_t *pgd;
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unsigned long next;
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unsigned long start = addr;
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unsigned long end = addr + 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(start, end);
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}
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static void unmap_vm_area(struct vm_struct *area)
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{
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unmap_kernel_range((unsigned long)area->addr, area->size);
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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(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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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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flush_cache_vmap((unsigned long) area->addr, end);
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return err;
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}
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EXPORT_SYMBOL_GPL(map_vm_area);
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static struct vm_struct *__get_vm_area_node(unsigned long size, unsigned long flags,
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unsigned long start, unsigned long end,
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int node, gfp_t gfp_mask)
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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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BUG_ON(in_interrupt());
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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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if (unlikely(!size))
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return NULL;
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area = kmalloc_node(sizeof(*area), gfp_mask & GFP_RECLAIM_MASK, node);
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if (unlikely(!area))
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return NULL;
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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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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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return __get_vm_area_node(size, flags, start, end, -1, GFP_KERNEL);
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}
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EXPORT_SYMBOL_GPL(__get_vm_area);
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/**
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* get_vm_area - reserve a contiguous kernel virtual area
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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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struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags,
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int node, gfp_t gfp_mask)
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{
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return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END, node,
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gfp_mask);
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}
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/* Caller must hold vmlist_lock */
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static struct vm_struct *__find_vm_area(void *addr)
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{
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struct vm_struct *tmp;
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for (tmp = vmlist; tmp != NULL; tmp = tmp->next) {
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if (tmp->addr == addr)
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break;
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}
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return tmp;
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}
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/* Caller must hold vmlist_lock */
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static 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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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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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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/*
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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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/**
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* remove_vm_area - find and remove a continuous kernel virtual area
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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, except for its size or flags.
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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 *v;
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write_lock(&vmlist_lock);
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v = __remove_vm_area(addr);
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write_unlock(&vmlist_lock);
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return v;
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}
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static 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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debug_check_no_locks_freed(addr, area->size);
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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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BUG_ON(!area->pages[i]);
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__free_page(area->pages[i]);
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}
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if (area->flags & VM_VPAGES)
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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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* @addr: memory base address
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*
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* Free the virtually continuous memory area starting at @addr, as
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* obtained from vmalloc(), vmalloc_32() or __vmalloc(). If @addr is
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* NULL, no operation is performed.
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*
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* Must 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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* @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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* Must 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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* @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_node(struct vm_struct *area, gfp_t gfp_mask,
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pgprot_t prot, int node)
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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_node(array_size, gfp_mask | __GFP_ZERO,
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PAGE_KERNEL, node);
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area->flags |= VM_VPAGES;
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} else {
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pages = kmalloc_node(array_size,
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(gfp_mask & GFP_RECLAIM_MASK) | __GFP_ZERO,
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node);
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}
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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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for (i = 0; i < area->nr_pages; i++) {
|
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if (node < 0)
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area->pages[i] = alloc_page(gfp_mask);
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else
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area->pages[i] = alloc_pages_node(node, gfp_mask, 0);
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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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|
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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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void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
|
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{
|
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return __vmalloc_area_node(area, gfp_mask, prot, -1);
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}
|
|
|
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/**
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* __vmalloc_node - allocate virtually contiguous memory
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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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* @node: node to use for allocation or -1
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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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static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
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int node)
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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_node(size, VM_ALLOC, node, gfp_mask);
|
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if (!area)
|
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return NULL;
|
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|
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return __vmalloc_area_node(area, gfp_mask, prot, node);
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}
|
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|
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void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
|
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{
|
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return __vmalloc_node(size, gfp_mask, prot, -1);
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}
|
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EXPORT_SYMBOL(__vmalloc);
|
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|
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/**
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* vmalloc - allocate virtually contiguous memory
|
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* @size: allocation size
|
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* Allocate enough pages to cover @size from the page level
|
|
* allocator and map them into contiguous kernel virtual space.
|
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*
|
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* For tight control 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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return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
|
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}
|
|
EXPORT_SYMBOL(vmalloc);
|
|
|
|
/**
|
|
* vmalloc_user - allocate zeroed virtually contiguous memory for userspace
|
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* @size: allocation size
|
|
*
|
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* The resulting memory area is zeroed so it can be mapped to userspace
|
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* without leaking data.
|
|
*/
|
|
void *vmalloc_user(unsigned long size)
|
|
{
|
|
struct vm_struct *area;
|
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void *ret;
|
|
|
|
ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
|
|
if (ret) {
|
|
write_lock(&vmlist_lock);
|
|
area = __find_vm_area(ret);
|
|
area->flags |= VM_USERMAP;
|
|
write_unlock(&vmlist_lock);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vmalloc_user);
|
|
|
|
/**
|
|
* vmalloc_node - allocate memory on a specific node
|
|
* @size: allocation size
|
|
* @node: numa node
|
|
*
|
|
* Allocate enough pages to cover @size from the page level
|
|
* allocator and map them into contiguous kernel virtual space.
|
|
*
|
|
* For tight control over page level allocator and protection flags
|
|
* use __vmalloc() instead.
|
|
*/
|
|
void *vmalloc_node(unsigned long size, int node)
|
|
{
|
|
return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL, node);
|
|
}
|
|
EXPORT_SYMBOL(vmalloc_node);
|
|
|
|
#ifndef PAGE_KERNEL_EXEC
|
|
# define PAGE_KERNEL_EXEC PAGE_KERNEL
|
|
#endif
|
|
|
|
/**
|
|
* vmalloc_exec - allocate virtually contiguous, executable memory
|
|
* @size: allocation size
|
|
*
|
|
* Kernel-internal function to allocate enough pages to cover @size
|
|
* the page level allocator and map them into contiguous and
|
|
* executable kernel virtual space.
|
|
*
|
|
* For tight control over page level allocator and protection flags
|
|
* use __vmalloc() instead.
|
|
*/
|
|
|
|
void *vmalloc_exec(unsigned long size)
|
|
{
|
|
return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
|
|
}
|
|
|
|
#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
|
|
#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL
|
|
#elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA)
|
|
#define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL
|
|
#else
|
|
#define GFP_VMALLOC32 GFP_KERNEL
|
|
#endif
|
|
|
|
/**
|
|
* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
|
|
* @size: allocation size
|
|
*
|
|
* Allocate enough 32bit PA addressable pages to cover @size from the
|
|
* page level allocator and map them into contiguous kernel virtual space.
|
|
*/
|
|
void *vmalloc_32(unsigned long size)
|
|
{
|
|
return __vmalloc(size, GFP_VMALLOC32, PAGE_KERNEL);
|
|
}
|
|
EXPORT_SYMBOL(vmalloc_32);
|
|
|
|
/**
|
|
* vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
|
|
* @size: allocation size
|
|
*
|
|
* The resulting memory area is 32bit addressable and zeroed so it can be
|
|
* mapped to userspace without leaking data.
|
|
*/
|
|
void *vmalloc_32_user(unsigned long size)
|
|
{
|
|
struct vm_struct *area;
|
|
void *ret;
|
|
|
|
ret = __vmalloc(size, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL);
|
|
if (ret) {
|
|
write_lock(&vmlist_lock);
|
|
area = __find_vm_area(ret);
|
|
area->flags |= VM_USERMAP;
|
|
write_unlock(&vmlist_lock);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vmalloc_32_user);
|
|
|
|
long vread(char *buf, char *addr, unsigned long count)
|
|
{
|
|
struct vm_struct *tmp;
|
|
char *vaddr, *buf_start = buf;
|
|
unsigned long n;
|
|
|
|
/* Don't allow overflow */
|
|
if ((unsigned long) addr + count < count)
|
|
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 = '\0';
|
|
buf++;
|
|
addr++;
|
|
count--;
|
|
}
|
|
n = vaddr + tmp->size - PAGE_SIZE - addr;
|
|
do {
|
|
if (count == 0)
|
|
goto finished;
|
|
*buf = *addr;
|
|
buf++;
|
|
addr++;
|
|
count--;
|
|
} while (--n > 0);
|
|
}
|
|
finished:
|
|
read_unlock(&vmlist_lock);
|
|
return buf - buf_start;
|
|
}
|
|
|
|
long vwrite(char *buf, char *addr, unsigned long count)
|
|
{
|
|
struct vm_struct *tmp;
|
|
char *vaddr, *buf_start = buf;
|
|
unsigned long n;
|
|
|
|
/* Don't allow overflow */
|
|
if ((unsigned long) addr + count < count)
|
|
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;
|
|
}
|
|
|
|
/**
|
|
* remap_vmalloc_range - map vmalloc pages to userspace
|
|
* @vma: vma to cover (map full range of vma)
|
|
* @addr: vmalloc memory
|
|
* @pgoff: number of pages into addr before first page to map
|
|
* @returns: 0 for success, -Exxx on failure
|
|
*
|
|
* This function checks that addr is a valid vmalloc'ed area, and
|
|
* that it is big enough to cover the vma. Will return failure if
|
|
* that criteria isn't met.
|
|
*
|
|
* Similar to remap_pfn_range() (see mm/memory.c)
|
|
*/
|
|
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
|
|
unsigned long pgoff)
|
|
{
|
|
struct vm_struct *area;
|
|
unsigned long uaddr = vma->vm_start;
|
|
unsigned long usize = vma->vm_end - vma->vm_start;
|
|
int ret;
|
|
|
|
if ((PAGE_SIZE-1) & (unsigned long)addr)
|
|
return -EINVAL;
|
|
|
|
read_lock(&vmlist_lock);
|
|
area = __find_vm_area(addr);
|
|
if (!area)
|
|
goto out_einval_locked;
|
|
|
|
if (!(area->flags & VM_USERMAP))
|
|
goto out_einval_locked;
|
|
|
|
if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
|
|
goto out_einval_locked;
|
|
read_unlock(&vmlist_lock);
|
|
|
|
addr += pgoff << PAGE_SHIFT;
|
|
do {
|
|
struct page *page = vmalloc_to_page(addr);
|
|
ret = vm_insert_page(vma, uaddr, page);
|
|
if (ret)
|
|
return ret;
|
|
|
|
uaddr += PAGE_SIZE;
|
|
addr += PAGE_SIZE;
|
|
usize -= PAGE_SIZE;
|
|
} while (usize > 0);
|
|
|
|
/* Prevent "things" like memory migration? VM_flags need a cleanup... */
|
|
vma->vm_flags |= VM_RESERVED;
|
|
|
|
return ret;
|
|
|
|
out_einval_locked:
|
|
read_unlock(&vmlist_lock);
|
|
return -EINVAL;
|
|
}
|
|
EXPORT_SYMBOL(remap_vmalloc_range);
|
|
|
|
/*
|
|
* Implement a stub for vmalloc_sync_all() if the architecture chose not to
|
|
* have one.
|
|
*/
|
|
void __attribute__((weak)) vmalloc_sync_all(void)
|
|
{
|
|
}
|
|
|
|
|
|
static int f(pte_t *pte, struct page *pmd_page, unsigned long addr, void *data)
|
|
{
|
|
/* apply_to_page_range() does all the hard work. */
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* alloc_vm_area - allocate a range of kernel address space
|
|
* @size: size of the area
|
|
* @returns: NULL on failure, vm_struct on success
|
|
*
|
|
* This function reserves a range of kernel address space, and
|
|
* allocates pagetables to map that range. No actual mappings
|
|
* are created. If the kernel address space is not shared
|
|
* between processes, it syncs the pagetable across all
|
|
* processes.
|
|
*/
|
|
struct vm_struct *alloc_vm_area(size_t size)
|
|
{
|
|
struct vm_struct *area;
|
|
|
|
area = get_vm_area(size, VM_IOREMAP);
|
|
if (area == NULL)
|
|
return NULL;
|
|
|
|
/*
|
|
* This ensures that page tables are constructed for this region
|
|
* of kernel virtual address space and mapped into init_mm.
|
|
*/
|
|
if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
|
|
area->size, f, NULL)) {
|
|
free_vm_area(area);
|
|
return NULL;
|
|
}
|
|
|
|
/* Make sure the pagetables are constructed in process kernel
|
|
mappings */
|
|
vmalloc_sync_all();
|
|
|
|
return area;
|
|
}
|
|
EXPORT_SYMBOL_GPL(alloc_vm_area);
|
|
|
|
void free_vm_area(struct vm_struct *area)
|
|
{
|
|
struct vm_struct *ret;
|
|
ret = remove_vm_area(area->addr);
|
|
BUG_ON(ret != area);
|
|
kfree(area);
|
|
}
|
|
EXPORT_SYMBOL_GPL(free_vm_area);
|