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authorrogersb11 <brettrogers11@gmail.com>2015-11-10 11:19:31 -0600
committerrogersb11 <brettrogers11@gmail.com>2015-11-10 14:01:25 -0500
commitb4d16f70c34ecb908c8a61e58ea51fecdd4a4b10 (patch)
tree973e9aeb97bb13497d17a43e6f3c070381bc5b87 /mm/memory.c
parentd177fbc2f0c263b06c18bda2eb46200a31bcbebd (diff)
parent5dba9ddd98cbc7ad319d687887981a0ea0062c75 (diff)
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Merge remote-tracking branch 'korg/linux-3.0.y' into cm-13.0
Conflicts: crypto/algapi.c drivers/gpu/drm/i915/i915_debugfs.c drivers/gpu/drm/i915/intel_display.c drivers/video/fbmem.c include/linux/nls.h kernel/cgroup.c kernel/signal.c kernel/timeconst.pl net/ipv4/ping.c Change-Id: I1f532925d1743df74d66bcdd6fc92f05c72ee0dd
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 6204ce2..5331e67 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2374,6 +2374,53 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
}
EXPORT_SYMBOL(remap_pfn_range);
+/**
+ * vm_iomap_memory - remap memory to userspace
+ * @vma: user vma to map to
+ * @start: start of area
+ * @len: size of area
+ *
+ * This is a simplified io_remap_pfn_range() for common driver use. The
+ * driver just needs to give us the physical memory range to be mapped,
+ * we'll figure out the rest from the vma information.
+ *
+ * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
+ * whatever write-combining details or similar.
+ */
+int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
+{
+ unsigned long vm_len, pfn, pages;
+
+ /* Check that the physical memory area passed in looks valid */
+ if (start + len < start)
+ return -EINVAL;
+ /*
+ * You *really* shouldn't map things that aren't page-aligned,
+ * but we've historically allowed it because IO memory might
+ * just have smaller alignment.
+ */
+ len += start & ~PAGE_MASK;
+ pfn = start >> PAGE_SHIFT;
+ pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
+ if (pfn + pages < pfn)
+ return -EINVAL;
+
+ /* We start the mapping 'vm_pgoff' pages into the area */
+ if (vma->vm_pgoff > pages)
+ return -EINVAL;
+ pfn += vma->vm_pgoff;
+ pages -= vma->vm_pgoff;
+
+ /* Can we fit all of the mapping? */
+ vm_len = vma->vm_end - vma->vm_start;
+ if (vm_len >> PAGE_SHIFT > pages)
+ return -EINVAL;
+
+ /* Ok, let it rip */
+ return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_iomap_memory);
+
static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
unsigned long addr, unsigned long end,
pte_fn_t fn, void *data)