[PATCH 3.16 12/99] MIPS: Align kernel load address to 64KB

From: Ben Hutchings
Date: Tue Apr 02 2019 - 09:48:46 EST


3.16.65-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Huacai Chen <chenhc@xxxxxxxxxx>

commit bec0de4cfad21bd284dbddee016ed1767a5d2823 upstream.

KEXEC needs the new kernel's load address to be aligned on a page
boundary (see sanity_check_segment_list()), but on MIPS the default
vmlinuz load address is only explicitly aligned to 16 bytes.

Since the largest PAGE_SIZE supported by MIPS kernels is 64KB, increase
the alignment calculated by calc_vmlinuz_load_addr to 64KB.

Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
Patchwork: https://patchwork.linux-mips.org/patch/21131/
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: James Hogan <james.hogan@xxxxxxxx>
Cc: Steven J . Hill <Steven.Hill@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Cc: Fuxin Zhang <zhangfx@xxxxxxxxxx>
Cc: Zhangjin Wu <wuzhangjin@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/mips/boot/compressed/calc_vmlinuz_load_addr.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/arch/mips/boot/compressed/calc_vmlinuz_load_addr.c
+++ b/arch/mips/boot/compressed/calc_vmlinuz_load_addr.c
@@ -13,6 +13,7 @@
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
+#include "../../../../include/linux/sizes.h"

int main(int argc, char *argv[])
{
@@ -45,11 +46,11 @@ int main(int argc, char *argv[])
vmlinuz_load_addr = vmlinux_load_addr + vmlinux_size;

/*
- * Align with 16 bytes: "greater than that used for any standard data
- * types by a MIPS compiler." -- See MIPS Run Linux (Second Edition).
+ * Align with 64KB: KEXEC needs load sections to be aligned to PAGE_SIZE,
+ * which may be as large as 64KB depending on the kernel configuration.
*/

- vmlinuz_load_addr += (16 - vmlinux_size % 16);
+ vmlinuz_load_addr += (SZ_64K - vmlinux_size % SZ_64K);

printf("0x%llx\n", vmlinuz_load_addr);