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author | Paul Mundt <lethal@linux-sh.org> | 2008-02-05 06:29:59 (GMT) |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-05 17:44:21 (GMT) |
commit | f905bc447c303fefcb180c7e8b641746ffa6cf87 (patch) | |
tree | 390d3f3490eb6b22a40598775538dd5bbd9653c1 /mm/nommu.c | |
parent | f156ac8c7aeddb2d85294b7a3b849178625e15e2 (diff) | |
download | linux-f905bc447c303fefcb180c7e8b641746ffa6cf87.tar.xz |
nommu: add new vmalloc_user() and remap_vmalloc_range() interfaces.
This builds on top of the earlier vmalloc_32_user() work introduced by
b50731732f926d6c49fd0724616a7344c31cd5cf, as we now have places in the nommu
allmodconfig that hit up against these missing APIs.
As vmalloc_32_user() is already implemented, this is moved over to
vmalloc_user() and simply made a wrapper. As all current nommu platforms are
32-bit addressable, there's no special casing we have to do for ZONE_DMA and
things of that nature as per GFP_VMALLOC32.
remap_vmalloc_range() needs to check VM_USERMAP in order to figure out whether
we permit the remap or not, which means that we also have to rework the
vmalloc_user() code to grovel for the VMA and set the flag.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: David McCullough <david_mccullough@securecomputing.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/nommu.c')
-rw-r--r-- | mm/nommu.c | 45 |
1 files changed, 44 insertions, 1 deletions
@@ -10,6 +10,7 @@ * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com> * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org> * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com> + * Copyright (c) 2007 Paul Mundt <lethal@linux-sh.org> */ #include <linux/module.h> @@ -183,6 +184,26 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) } EXPORT_SYMBOL(__vmalloc); +void *vmalloc_user(unsigned long size) +{ + void *ret; + + ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, + PAGE_KERNEL); + if (ret) { + struct vm_area_struct *vma; + + down_write(¤t->mm->mmap_sem); + vma = find_vma(current->mm, (unsigned long)ret); + if (vma) + vma->vm_flags |= VM_USERMAP; + up_write(¤t->mm->mmap_sem); + } + + return ret; +} +EXPORT_SYMBOL(vmalloc_user); + struct page *vmalloc_to_page(const void *addr) { return virt_to_page(addr); @@ -253,10 +274,17 @@ EXPORT_SYMBOL(vmalloc_32); * * The resulting memory area is 32bit addressable and zeroed so it can be * mapped to userspace without leaking data. + * + * VM_USERMAP is set on the corresponding VMA so that subsequent calls to + * remap_vmalloc_range() are permissible. */ void *vmalloc_32_user(unsigned long size) { - return __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL); + /* + * We'll have to sort out the ZONE_DMA bits for 64-bit, + * but for now this can simply use vmalloc_user() directly. + */ + return vmalloc_user(size); } EXPORT_SYMBOL(vmalloc_32_user); @@ -1216,6 +1244,21 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, } EXPORT_SYMBOL(remap_pfn_range); +int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, + unsigned long pgoff) +{ + unsigned int size = vma->vm_end - vma->vm_start; + + if (!(vma->vm_flags & VM_USERMAP)) + return -EINVAL; + + vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); + vma->vm_end = vma->vm_start + size; + + return 0; +} +EXPORT_SYMBOL(remap_vmalloc_range); + void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) { } |