s390/kaslr: add support for R_390_GLOB_DAT relocation type (ac49303d) · Commits · 戴 / test

Commit "bpf: Process in-kernel BTF" in linux-next introduced an undefined __weak symbol, which results in an R_390_GLOB_DAT relocation type. That is not yet handled by the KASLR relocation code, and the kernel stops with the message "Unknown relocation type". Add code to detect and handle R_390_GLOB_DAT relocation types and undefined symbols. Fixes: ("s390/kernel: build a relocatable kernel") Cc: <stable@vger.kernel.org> # v5.2+ Acked-by:

Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by:

Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by:

Vasily Gorbik <gor@linux.ibm.com>

arch/s390/boot/startup.c

+11 −3

Original line number	Diff line number	Diff line
		@@ -101,10 +101,18 @@ static void handle_relocs(unsigned long offset)
		dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
		for (rela = rela_start; rela < rela_end; rela++) {
		loc = rela->r_offset + offset;
		val = rela->r_addend + offset;
		val = rela->r_addend;
		r_sym = ELF64_R_SYM(rela->r_info);
		if (r_sym)
		val += dynsym[r_sym].st_value;
		if (r_sym) {
		if (dynsym[r_sym].st_shndx != SHN_UNDEF)
		val += dynsym[r_sym].st_value + offset;
		} else {
		/*
		* 0 == undefined symbol table index (STN_UNDEF),
		* used for R_390_RELATIVE, only add KASLR offset
		*/
		val += offset;
		}
		r_type = ELF64_R_TYPE(rela->r_info);
		rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
		if (rc)

arch/s390/kernel/machine_kexec_reloc.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@ int arch_kexec_do_relocs(int r_type, void *loc, unsigned long val,
		(u32 )loc = val;
		break;
		case R_390_64: /* Direct 64 bit. */
		case R_390_GLOB_DAT:
		(u64 )loc = val;
		break;
		case R_390_PC16: /* PC relative 16 bit. */

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