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authorGerald Schaefer <gerald.schaefer@de.ibm.com>2019-10-21 19:56:00 +0200
committerVasily Gorbik <gor@linux.ibm.com>2019-10-22 17:55:51 +0200
commitac49303d9ef0ad98b79867a380ef23480e48870b (patch)
tree712a6f50423cbf0bf3bd3e99a56789cf8b00dacc /arch/s390/boot
parent388bb19be8eab4674a660e0c97eaf60775362bc7 (diff)
s390/kaslr: add support for R_390_GLOB_DAT relocation type
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: 805bc0bc238f ("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>
Diffstat (limited to 'arch/s390/boot')
-rw-r--r--arch/s390/boot/startup.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index 596ca7cc4d7b..5367950510f6 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -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)