vmalloc: introduce remap_vmalloc_range_partial
We want to allocate ELF note segment buffer on the 2nd kernel in vmalloc
space and remap it to user-space in order to reduce the risk that memory
allocation fails on system with huge number of CPUs and so with huge ELF
note segment that exceeds 11-order block size.
Although there's already remap_vmalloc_range for the purpose of
remapping vmalloc memory to user-space, we need to specify user-space
range via vma.
Mmap on /proc/vmcore needs to remap range across multiple objects, so
the interface that requires vma to cover full range is problematic.
This patch introduces remap_vmalloc_range_partial that receives user-space
range as a pair of base address and size and can be used for mmap on
/proc/vmcore case.
remap_vmalloc_range is rewritten using remap_vmalloc_range_partial.
[akpm@linux-foundation.org: use PAGE_ALIGNED()]
Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 3875fa2..b725990 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1476,10 +1476,9 @@
if (!addr)
return;
- if ((PAGE_SIZE-1) & (unsigned long)addr) {
- WARN(1, KERN_ERR "Trying to vfree() bad address (%p)\n", addr);
+ if (WARN(!PAGE_ALIGNED(addr), "Trying to vfree() bad address (%p)\n",
+ addr));
return;
- }
area = remove_vm_area(addr);
if (unlikely(!area)) {
@@ -2148,6 +2147,61 @@
}
/**
+ * remap_vmalloc_range_partial - map vmalloc pages to userspace
+ * @vma: vma to cover
+ * @uaddr: target user address to start at
+ * @kaddr: virtual address of vmalloc kernel memory
+ * @size: size of map area
+ *
+ * Returns: 0 for success, -Exxx on failure
+ *
+ * This function checks that @kaddr is a valid vmalloc'ed area,
+ * and that it is big enough to cover the range starting at
+ * @uaddr in @vma. Will return failure if that criteria isn't
+ * met.
+ *
+ * Similar to remap_pfn_range() (see mm/memory.c)
+ */
+int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
+ void *kaddr, unsigned long size)
+{
+ struct vm_struct *area;
+
+ size = PAGE_ALIGN(size);
+
+ if (!PAGE_ALIGNED(uaddr) || !PAGE_ALIGNED(kaddr))
+ return -EINVAL;
+
+ area = find_vm_area(kaddr);
+ if (!area)
+ return -EINVAL;
+
+ if (!(area->flags & VM_USERMAP))
+ return -EINVAL;
+
+ if (kaddr + size > area->addr + area->size)
+ return -EINVAL;
+
+ do {
+ struct page *page = vmalloc_to_page(kaddr);
+ int ret;
+
+ ret = vm_insert_page(vma, uaddr, page);
+ if (ret)
+ return ret;
+
+ uaddr += PAGE_SIZE;
+ kaddr += PAGE_SIZE;
+ size -= PAGE_SIZE;
+ } while (size > 0);
+
+ vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
+
+ return 0;
+}
+EXPORT_SYMBOL(remap_vmalloc_range_partial);
+
+/**
* remap_vmalloc_range - map vmalloc pages to userspace
* @vma: vma to cover (map full range of vma)
* @addr: vmalloc memory
@@ -2164,40 +2218,9 @@
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;
-
- if ((PAGE_SIZE-1) & (unsigned long)addr)
- return -EINVAL;
-
- area = find_vm_area(addr);
- if (!area)
- return -EINVAL;
-
- if (!(area->flags & VM_USERMAP))
- return -EINVAL;
-
- if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)
- return -EINVAL;
-
- addr += pgoff << PAGE_SHIFT;
- do {
- struct page *page = vmalloc_to_page(addr);
- int ret;
-
- ret = vm_insert_page(vma, uaddr, page);
- if (ret)
- return ret;
-
- uaddr += PAGE_SIZE;
- addr += PAGE_SIZE;
- usize -= PAGE_SIZE;
- } while (usize > 0);
-
- vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
-
- return 0;
+ return remap_vmalloc_range_partial(vma, vma->vm_start,
+ addr + (pgoff << PAGE_SHIFT),
+ vma->vm_end - vma->vm_start);
}
EXPORT_SYMBOL(remap_vmalloc_range);