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

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Date:   Tue, 02 Apr 2019 14:38:27 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Huacai Chen" <chenhc@...ote.com>, linux-mips@...ux-mips.org,
        "Ralf Baechle" <ralf@...ux-mips.org>,
        "Steven J . Hill" <Steven.Hill@...ium.com>,
        "Fuxin Zhang" <zhangfx@...ote.com>,
        "Paul Burton" <paul.burton@...s.com>,
        "Zhangjin Wu" <wuzhangjin@...il.com>,
        "James Hogan" <james.hogan@...s.com>
Subject: [PATCH 3.16 12/99] MIPS: Align kernel load address to 64KB

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

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

From: Huacai Chen <chenhc@...ote.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@...ote.com>
Signed-off-by: Paul Burton <paul.burton@...s.com>
Patchwork: https://patchwork.linux-mips.org/patch/21131/
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: James Hogan <james.hogan@...s.com>
Cc: Steven J . Hill <Steven.Hill@...ium.com>
Cc: linux-mips@...ux-mips.org
Cc: Fuxin Zhang <zhangfx@...ote.com>
Cc: Zhangjin Wu <wuzhangjin@...il.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 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);