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From:   Jinyang He <hejinyang@loongson.cn>
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Huacai Chen <chenhc@lemote.com>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc:     linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 3/3] MIPS: KASLR: Make relocation_address can be configured
Date:   Thu, 19 Nov 2020 10:29:14 +0800
Message-Id: <1605752954-10368-3-git-send-email-hejinyang@loongson.cn>
In-Reply-To: <1605752954-10368-1-git-send-email-hejinyang@loongson.cn>
References: <1605752954-10368-1-git-send-email-hejinyang@loongson.cn>
Precedence: bulk

When CONFIG_RANDOMIZE_BASE is not set, determine_relocation_address()
always returns a constant. It is not friendly to users if the address
cannot be used. Make it can be configured at Kconfig.

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
---
 arch/mips/Kconfig           | 5 +++++
 arch/mips/kernel/relocate.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 1508829..1c95478 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2803,6 +2803,11 @@ config RELOCATION_TABLE_SIZE
 
 	  If unsure, leave at the default value.
 
+config RELOCATE_DESTINATION
+	hex "Relocate address when RANDOMIZE_BASE is not set"
+	depends on RELOCATABLE && !RANDOMIZE_BASE
+	default "0xffffffff81000000"
+
 config RANDOMIZE_BASE
 	bool "Randomize the address of the kernel image"
 	depends on RELOCATABLE
diff --git a/arch/mips/kernel/relocate.c b/arch/mips/kernel/relocate.c
index 709cfa0..b7ea6ff 100644
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c
@@ -276,7 +276,7 @@ static inline void __init *determine_relocation_address(void)
 	 * Choose a new address for the kernel
 	 * For now we'll hard code the destination
 	 */
-	return (void *)0xffffffff81000000;
+	return (void *)CONFIG_RELOCATE_DESTINATION;
 }
 
 #endif
-- 
2.1.0