[PATCH] LoongArch: Fix an issue with relocatable vmlinux

From: WANG Rui <wangrui@loongson.cn>
To: kexec@lists.infradead.org
Cc: Varad Gautam <vrd@amazon.de>,
	AKASHI Takahiro <takahiro.akashi@linaro.org>,
	Huacai Chen <chenhuacai@kernel.org>,
	WANG Rui <wangrui@loongson.cn>
Subject: [PATCH] LoongArch: Fix an issue with relocatable vmlinux
Date: Fri, 24 Nov 2023 16:54:10 +0800	[thread overview]
Message-ID: <20231124085410.107080-1-wangrui@loongson.cn> (raw)

Normally vmlinux for LoongArch is of ET_EXEC type, while if built with
CONFIG_RELOCATABLE (this is PIE) and Clang, it will be of ET_DYN type.
Meanwhile, physical address field of segments in vmlinux has actually
the same value as virtual address field.

Similar to arm64, this patch allows to unconditionally skip the check
on LoongArch.

Link: https://github.com/ClangBuiltLinux/linux/issues/1963
Signed-off-by: WANG Rui <wangrui@loongson.cn>
---
 kexec/kexec-elf-exec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kexec/kexec-elf-exec.c b/kexec/kexec-elf-exec.c
index bea7b3e..b337642 100644
--- a/kexec/kexec-elf-exec.c
+++ b/kexec/kexec-elf-exec.c
@@ -39,12 +39,13 @@ static int get_elf_exec_load_base(struct mem_ehdr *ehdr, struct kexec_info *info
 	unsigned long first, last;
 	size_t i;
 
-	/* Note on arm64:
+	/* Note on arm64 and loongarch64:
 	 * arm64's vmlinux has virtual address in physical address
 	 * field of PT_LOAD segments. So the following validity check
 	 * and relocation makes no sense on arm64.
+	 * This is also applies to LoongArch.
 	 */
-	if (ehdr->e_machine == EM_AARCH64)
+	if (ehdr->e_machine == EM_AARCH64 || ehdr->e_machine == EM_LOONGARCH)
 		return 0;
 
 	first = ULONG_MAX;
-- 
2.43.0


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