arm64: vmlinux.lds: make __rela_offset and __dynsym_offset ABSOLUTE

Due to the untyped KIMAGE_VADDR constant, the linker may not notice
that the __rela_offset and __dynsym_offset expressions are absolute
values (i.e., are not subject to relocation). This does not matter for
KASLR, but it does confuse kallsyms in relative mode, since it uses
the lowest non-absolute symbol address as the anchor point, and expects
all other symbol addresses to be within 4 GB of it.

Fix this by qualifying these expressions as ABSOLUTE() explicitly.

Fixes: 0cd3defe0af4 ("arm64: kernel: perform relocation processing from ID map")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(cherry picked from commit d6732fc402c2665f61e72faf206a0268e65236e9)
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Author: Ard Biesheuvel

arch/arm64/kernel/vmlinux.lds.S

@@ -168,9 +168,9 @@ SECTIONS
 		*(.hash)
 	}
 
-	__rela_offset	= ADDR(.rela) - KIMAGE_VADDR;
+	__rela_offset	= ABSOLUTE(ADDR(.rela) - KIMAGE_VADDR);
 	__rela_size	= SIZEOF(.rela);
-	__dynsym_offset	= ADDR(.dynsym) - KIMAGE_VADDR;
+	__dynsym_offset	= ABSOLUTE(ADDR(.dynsym) - KIMAGE_VADDR);
 
 	. = ALIGN(SEGMENT_ALIGN);
 	__init_end = .;