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authorKamalesh Babulal <kamalesh@linux.vnet.ibm.com>2017-11-14 04:29:08 -0500
committerMichael Ellerman <mpe@ellerman.id.au>2017-12-11 13:03:28 +1100
commita443bf6e8a7674b86221f4922cae82d67dc9e8ad (patch)
treee034083a3bb332df792e8c3ee8f6579cc59e8910
parent5138b31422efec897461951f7ce72e59bbb9cb1a (diff)
powerpc/modules: Add REL24 relocation support of livepatch symbols
Livepatch re-uses module loader function apply_relocate_add() to write relocations, instead of managing them by arch-dependent klp_write_module_reloc() function. apply_relocate_add() doesn't understand livepatch symbols (marked with SHN_LIVEPATCH symbol section index) and assumes them to be local symbols by default for R_PPC64_REL24 relocation type. It fails with an error, when trying to calculate offset with local_entry_offset(): module_64: kpatch_meminfo: REL24 -1152921504897399800 out of range! Whereas livepatch symbols are essentially SHN_UNDEF, should be called via stub used for global calls. This issue can be fixed by teaching apply_relocate_add() to handle both SHN_UNDEF/SHN_LIVEPATCH symbols via the same stub. This patch extends SHN_UNDEF code to handle livepatch symbols too. Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/kernel/module_64.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 759104b99f9f..1685b40f3935 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -614,7 +614,8 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
case R_PPC_REL24:
/* FIXME: Handle weak symbols here --RR */
- if (sym->st_shndx == SHN_UNDEF) {
+ if (sym->st_shndx == SHN_UNDEF ||
+ sym->st_shndx == SHN_LIVEPATCH) {
/* External: go via stub */
value = stub_for_addr(sechdrs, value, me);
if (!value)