LoongArch: Apply dynamic relocations for LLD

For the following assembly code:

     .text
     .global func
 func:
     nop

     .data
 var:
     .dword func

When linked with `-pie`, GNU LD populates the `var` variable with the
pre-relocated value of `func`. However, LLVM LLD does not exhibit the
same behavior. This issue also arises with the `kernel_entry` in arch/
loongarch/kernel/head.S:

 _head:
     .word   MZ_MAGIC                /* "MZ", MS-DOS header */
     .org    0x8
     .dword  kernel_entry            /* Kernel entry point */

The correct kernel entry from the MS-DOS header is crucial for jumping
to vmlinux from zboot. This necessity is why the compressed relocatable
kernel compiled by Clang encounters difficulties in booting.

To address this problem, it is proposed to apply dynamic relocations to
place with `--apply-dynamic-relocs`.

Link: https://github.com/ClangBuiltLinux/linux/issues/1962
Signed-off-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index 204b94b2e6aaa6e3afc71b292004fb3b329256b2..4ba8d67ddb097743be4e68493604579142eee2d5 100644 (file)
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -83,7 +83,7 @@ endif
 
 ifeq ($(CONFIG_RELOCATABLE),y)
 KBUILD_CFLAGS_KERNEL           += -fPIE
-LDFLAGS_vmlinux                        += -static -pie --no-dynamic-linker -z notext
+LDFLAGS_vmlinux                        += -static -pie --no-dynamic-linker -z notext $(call ld-option, --apply-dynamic-relocs)
 endif
 
 cflags-y += $(call cc-option, -mno-check-zero-division)