Hi,
On 08/31/2018 06:01 PM, Amit Singh Tomar wrote:
While porting XEN on Amlogic SoC we found that in absence of
image_size field of XEN image header, bootloader(U-BOOT)
relocates[1] the XEN image to an address(not appropriate
for Amlogic) derived from text_offset.
IHMO, this is a bug in U-Boot rather than Xen. The current format, while
old, is still valid.
In the case of U-Boot, you usually need to be really careful on the
position of all the blobs (e.g Xen, DTB, Kernel, Initramfs) in the memory.
This unwanted situation can be fixed by updating image_size field
along side kernel flags so that image wouldn't relocate from initial
load address.
I think the first step is to fix your U-boot and rethink where you load
your binaries.
Regarding the patch in itself, I think this is a good addition as it
allow Xen to be loaded in more places. But please rewrite the commit
message accordingly, this is an update to a new version.
[1]:https://git.denx.de/?p=u-boot.git;a=blob;f=arch/arm/lib/image.c;h=699bf44e702f7a7084997406203fd7d2aaaf87fa;hb=HEAD#l50
These changes are derived from kernel v4.18 files
Signed-off-by: Amit Singh Tomar <amittome...@gmail.com>
---
xen/arch/arm/arm64/head.S | 5 ++-
xen/arch/arm/arm64/lib/assembler.h | 11 +++++
xen/arch/arm/xen.lds.S | 3 ++
xen/include/asm-arm/arm64/linux_header_vars.h | 62 +++++++++++++++++++++++++++
4 files changed, 79 insertions(+), 2 deletions(-)
create mode 100644 xen/include/asm-arm/arm64/linux_header_vars.h
diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index d63734f..ce72c95 100644
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -25,6 +25,7 @@
#include <asm/early_printk.h>
#include <efi/efierr.h>
#include <asm/arm64/efibind.h>
+#include "lib/assembler.h"
#define PT_PT 0xf7f /* nG=1 AF=1 SH=11 AP=01 NS=1 ATTR=111 T=1 P=1 */
#define PT_MEM 0xf7d /* nG=1 AF=1 SH=11 AP=01 NS=1 ATTR=111 T=0 P=1 */
@@ -120,8 +121,8 @@ efi_head:
add x13, x18, #0x16
b real_start /* branch to kernel start */
.quad 0 /* Image load offset from start of RAM */
- .quad 0 /* reserved */
- .quad 0 /* reserved */
+ le64sym _kernel_size_le /* Effective size of kernel image,
little-endian */
+ le64sym _kernel_flags_le /* Informative flags, little-endian */
All the dance for to convert to little endian is not necessary on Xen.
Please rework your series to avoid such code, this would also reduce
quite significantly the series.
Cheers,
--
Julien Grall
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