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MIPS: Align kernel load address to 64KB

Subject: MIPS: Align kernel load address to 64KB
From: Huacai Chen <chenhc@lemote.com>
Date: Thu, 15 Nov 2018 15:53:56 +0800
From: Huacai Chen <chenhc@lemote.com>

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@lemote.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21131/
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <james.hogan@mips.com>
Cc: Steven J . Hill <Steven.Hill@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: <stable@vger.kernel.org> # 2.6.36+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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);
 


Patches currently in stable-queue which might be from chenhc@lemote.com are

queue-3.18/mips-ensure-pmd_present-returns-false-after-pmd_mknotpresent.patch
queue-3.18/mips-align-kernel-load-address-to-64kb.patch

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