linux-kernel - [PATCH] LoongArch: Automatically disable KASLR for hibernation

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Date: Tue, 25 Jun 2024 14:16:31 +0800
From: Huacai Chen <chenhuacai@...ngson.cn>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev,
	Xuefeng Li <lixuefeng@...ngson.cn>,
	Guo Ren <guoren@...nel.org>,
	Xuerui Wang <kernel@...0n.name>,
	Jiaxun Yang <jiaxun.yang@...goat.com>,
	linux-kernel@...r.kernel.org,
	loongson-kernel@...ts.loongnix.cn,
	Huacai Chen <chenhuacai@...ngson.cn>
Subject: [PATCH] LoongArch: Automatically disable KASLR for hibernation

Hibernation assumes the memory layout after resume be the same as that
before sleep, so it expects the kernel is loaded at the same position.
To achieve this goal we automatically disable KASLR if user explicitly
requests hibernation via the "resume=" command line. Since "nohibernate"
and "noresume" have higher priorities than "resume=", we only disable
KASLR if there is no "nohibernate" and "noresume".

Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
 arch/loongarch/kernel/relocate.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c
index 1acfa704c8d0..6834d627ff20 100644
--- a/arch/loongarch/kernel/relocate.c
+++ b/arch/loongarch/kernel/relocate.c
@@ -123,6 +123,32 @@ static inline __init bool kaslr_disabled(void)
 	if (str == boot_command_line || (str > boot_command_line && *(str - 1) == ' '))
 		return true;
 
+#ifdef CONFIG_HIBERNATION
+	str = strstr(builtin_cmdline, "nohibernate");
+	if (str == builtin_cmdline || (str > builtin_cmdline && *(str - 1) == ' '))
+		return false;
+
+	str = strstr(boot_command_line, "nohibernate");
+	if (str == boot_command_line || (str > boot_command_line && *(str - 1) == ' '))
+		return false;
+
+	str = strstr(builtin_cmdline, "noresume");
+	if (str == builtin_cmdline || (str > builtin_cmdline && *(str - 1) == ' '))
+		return false;
+
+	str = strstr(boot_command_line, "noresume");
+	if (str == boot_command_line || (str > boot_command_line && *(str - 1) == ' '))
+		return false;
+
+	str = strstr(builtin_cmdline, "resume=");
+	if (str == builtin_cmdline || (str > builtin_cmdline && *(str - 1) == ' '))
+		return true;
+
+	str = strstr(boot_command_line, "resume=");
+	if (str == boot_command_line || (str > boot_command_line && *(str - 1) == ' '))
+		return true;
+#endif
+
 	return false;
 }
 
-- 
2.43.0