Commit f905bc44 authored by Paul Mundt's avatar Paul Mundt Committed by Linus Torvalds
Browse files

nommu: add new vmalloc_user() and remap_vmalloc_range() interfaces. 



This builds on top of the earlier vmalloc_32_user() work introduced by
b5073173, 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: default avatarPaul Mundt <lethal@linux-sh.org>
Acked-by: default avatarDavid McCullough <david_mccullough@securecomputing.com>
Acked-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarGreg Ungerer <gerg@snapgear.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f156ac8c

mm/nommu.c

+44 −1
Original line number Diff line number Diff line
@@ -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(&current->mm->mmap_sem);

		vma = find_vma(current->mm, (unsigned long)ret);

		if (vma)

			vma->vm_flags |= VM_USERMAP;

		up_write(&current->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)

{

}