From 08ade00fbb088b8f5a1af706ee970c26cf842bf0 Mon Sep 17 00:00:00 2001 From: WANG Rui Date: Thu, 21 May 2026 20:58:36 +0800 Subject: [PATCH] LoongArch: Skip relocation-time KASLR if already applied When the kernel is relocated during early boot (efistub or kexec_file), a randomized load address may has already been selected and applied. In this case, performing KASLR again in relocate.c is unnecessary. Note: strictly-defined KASLR means the kernel's final runtime address has a random offset from the kernel's load address, which is implemented in relocate.c; broadly-defined KALSR means the kernel's final runtime address has a random offset from the kernel's link address (a.k.a. VMLINUX_LOAD_ADDRESS), which also include the efistlub implementation, kexec_file implementation and QEMU direct kernel boot. kaslr_disabled() return true only means strictly-defined KASLR is disabled. Acked-by: Ard Biesheuvel Signed-off-by: WANG Rui Signed-off-by: Huacai Chen --- arch/loongarch/kernel/relocate.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c index 16f6a9b39659..0a045964fad5 100644 --- a/arch/loongarch/kernel/relocate.c +++ b/arch/loongarch/kernel/relocate.c @@ -134,11 +134,23 @@ early_param("nokaslr", nokaslr); #define KASLR_DISABLED_MESSAGE "KASLR is disabled by %s in %s cmdline.\n" +/* + * Note: strictly-defined KASLR means the kernel's final runtime address + * has a random offset from the kernel's load address, which is implemented + * in relocate.c; broadly-defined KALSR means the kernel's final runtime + * address has a random offset from the kernel's link address (a.k.a. + * VMLINUX_LOAD_ADDRESS), which also include the efistlub implementation, + * kexec_file implementation and QEMU direct kernel boot. kaslr_disabled() + * return true only means strictly-defined KASLR is disabled. + */ static inline __init bool kaslr_disabled(void) { char *str; const char *builtin_cmdline = CONFIG_CMDLINE; + if (kaslr_offset()) + return true; /* KASLR is performed during early boot. */ + str = strstr(builtin_cmdline, "nokaslr"); if (str == builtin_cmdline || (str > builtin_cmdline && *(str - 1) == ' ')) { pr_info(KASLR_DISABLED_MESSAGE, "\'nokaslr\'", "built-in");