[Qemu-devel] [PATCH] loader: pad kernel size when loaded from a uImage

[Hollis Blanchard <hollis@penguinppc.org>]

The kernel's BSS size is lost by mkimage, which only considers file
size. As a result, loading other blobs (e.g. device tree, initrd)
immediately after the kernel location can result in them being zeroed by
the kernel's BSS initialization code.

Signed-off-by: Hollis Blanchard <hollis@penguinppc.org>
---
 hw/loader.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/hw/loader.c b/hw/loader.c
index 79a6f95..35bc25a 100644
--- a/hw/loader.c
+++ b/hw/loader.c
@@ -507,6 +507,13 @@ int load_uimage(const char *filename, target_phys_addr_t *ep,
 
     ret = hdr->ih_size;
 
+	/* The kernel's BSS size is lost by mkimage, which only considers file
+	 * size. We don't know how big it is, but we do know we can't place
+	 * anything immediately after the kernel. The padding seems like it should
+	 * be proportional to overall file size, but we also make sure it's at
+	 * least 4-byte aligned. */
+	ret += (hdr->ih_size / 16) & ~0x3;
+
 out:
     if (data)
         qemu_free(data);
-- 
1.7.1.1