BACKPORT: binder: add functions to copy to/from binder buffers
Avoid vm_area when copying to or from binder buffers.
Instead, new copy functions are added that copy from
kernel space to binder buffer space. These use
kmap_atomic() and kunmap_atomic() to create temporary
mappings and then memcpy() is used to copy within
that page.
Also, kmap_atomic() / kunmap_atomic() use the appropriate
cache flushing to support VIVT cache architectures.
Allow binder to build if CPU_CACHE_VIVT is defined.
Several uses of the new functions are added here. More
to follow in subsequent patches.
(cherry picked from commit 8ced0c6231ead26eca8cb416dcb7cc1c2cdd41d8)
Bug: 67668716
Change-Id: I6a93d2396d0a80c352a1d563fc7fb523a753e38c
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 0cfcaec..fed90af 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -1131,3 +1131,62 @@
}
return 0;
}
+
+static void binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
+ bool to_buffer,
+ struct binder_buffer *buffer,
+ binder_size_t buffer_offset,
+ void *ptr,
+ size_t bytes)
+{
+ /* All copies must be 32-bit aligned and 32-bit size */
+ BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes));
+
+ while (bytes) {
+ unsigned long size;
+ struct page *page;
+ pgoff_t pgoff;
+ void *tmpptr;
+ void *base_ptr;
+
+ page = binder_alloc_get_page(alloc, buffer,
+ buffer_offset, &pgoff);
+ size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
+ base_ptr = kmap_atomic(page);
+ tmpptr = base_ptr + pgoff;
+ if (to_buffer)
+ memcpy(tmpptr, ptr, size);
+ else
+ memcpy(ptr, tmpptr, size);
+ /*
+ * kunmap_atomic() takes care of flushing the cache
+ * if this device has VIVT cache arch
+ */
+ kunmap_atomic(base_ptr);
+ bytes -= size;
+ pgoff = 0;
+ ptr = ptr + size;
+ buffer_offset += size;
+ }
+}
+
+void binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
+ struct binder_buffer *buffer,
+ binder_size_t buffer_offset,
+ void *src,
+ size_t bytes)
+{
+ binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
+ src, bytes);
+}
+
+void binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
+ void *dest,
+ struct binder_buffer *buffer,
+ binder_size_t buffer_offset,
+ size_t bytes)
+{
+ binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
+ dest, bytes);
+}
+