This is a note to let you know that I've just added the patch titled
objtool: Teach get_alt_entry() about more relocation types
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
objtool-teach-get_alt_entry-about-more-relocation-types.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Tue Jul 12 05:07:35 PM CEST 2022
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Thu, 30 Sep 2021 12:43:10 +0200
Subject: objtool: Teach get_alt_entry() about more relocation types
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 24ff652573754fe4c03213ebd26b17e86842feb3 upstream.
Occasionally objtool encounters symbol (as opposed to section)
relocations in .altinstructions. Typically they are the alternatives
written by elf_add_alternative() as encountered on a noinstr
validation run on vmlinux after having already ran objtool on the
individual .o files.
Basically this is the counterpart of commit 44f6a7c0755d ("objtool:
Fix seg fault with Clang non-section symbols"), because when these new
assemblers (binutils now also does this) strip the section symbols,
elf_add_reloc_to_insn() is forced to emit symbol based relocations.
As such, teach get_alt_entry() about different relocation types.
Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls")
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Reported-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/YVWUvknIEVNkPvnP@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/objtool/special.c | 32 +++++++++++++++++++++++++-------
1 file changed, 25 insertions(+), 7 deletions(-)
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -55,6 +55,24 @@ void __weak arch_handle_alternative(unsi
{
}
+static bool reloc2sec_off(struct reloc *reloc, struct section **sec, unsigned long *off)
+{
+ switch (reloc->sym->type) {
+ case STT_FUNC:
+ *sec = reloc->sym->sec;
+ *off = reloc->sym->offset + reloc->addend;
+ return true;
+
+ case STT_SECTION:
+ *sec = reloc->sym->sec;
+ *off = reloc->addend;
+ return true;
+
+ default:
+ return false;
+ }
+}
+
static int get_alt_entry(struct elf *elf, struct special_entry *entry,
struct section *sec, int idx,
struct special_alt *alt)
@@ -87,15 +105,12 @@ static int get_alt_entry(struct elf *elf
WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
return -1;
}
- if (orig_reloc->sym->type != STT_SECTION) {
- WARN_FUNC("don't know how to handle non-section reloc symbol %s",
+ if (!reloc2sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off)) {
+ WARN_FUNC("don't know how to handle reloc symbol type: %s",
sec, offset + entry->orig, orig_reloc->sym->name);
return -1;
}
- alt->orig_sec = orig_reloc->sym->sec;
- alt->orig_off = orig_reloc->addend;
-
if (!entry->group || alt->new_len) {
new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new);
if (!new_reloc) {
@@ -112,8 +127,11 @@ static int get_alt_entry(struct elf *elf
if (arch_is_retpoline(new_reloc->sym))
return 1;
- alt->new_sec = new_reloc->sym->sec;
- alt->new_off = (unsigned int)new_reloc->addend;
+ if (!reloc2sec_off(new_reloc, &alt->new_sec, &alt->new_off)) {
+ WARN_FUNC("don't know how to handle reloc symbol type: %s",
+ sec, offset + entry->new, new_reloc->sym->name);
+ return -1;
+ }
/* _ASM_EXTABLE_EX hack */
if (alt->new_off >= 0x7ffffff0)
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-5.10/objtool-cache-instruction-relocs.patch
queue-5.10/x86-sev-avoid-using-__x86_return_thunk.patch
queue-5.10/objtool-add-elf_create_undef_symbol.patch
queue-5.10/x86-ftrace-use-alternative-ret-encoding.patch
queue-5.10/objtool-re-add-unwind_hint_-save_restore.patch
queue-5.10/x86-bugs-add-retbleed-ibpb.patch
queue-5.10/x86-bugs-enable-stibp-for-jmp2ret.patch
queue-5.10/x86-retpoline-cleanup-some-ifdefery.patch
queue-5.10/objtool-handle-__sanitize_cov-tail-calls.patch
queue-5.10/x86-prepare-asm-files-for-straight-line-speculation.patch
queue-5.10/kvm-vmx-flatten-__vmx_vcpu_run.patch
queue-5.10/x86-kvm-vmx-make-noinstr-clean.patch
queue-5.10/objtool-x86-replace-alternatives-with-.retpoline_sites.patch
queue-5.10/objtool-skip-magical-retpoline-.altinstr_replacement.patch
queue-5.10/x86-retbleed-add-fine-grained-kconfig-knobs.patch
queue-5.10/x86-cpu-amd-add-spectral-chicken.patch
queue-5.10/objtool-add-straight-line-speculation-validation.patch
queue-5.10/kvm-vmx-fix-ibrs-handling-after-vmexit.patch
queue-5.10/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch
queue-5.10/x86-vsyscall_emu-64-don-t-use-ret-in-vsyscall-emulation.patch
queue-5.10/tools-arch-update-arch-x86-lib-mem-cpy-set-_64.s-copies-used-in-perf-bench-mem-memcpy.patch
queue-5.10/x86-add-straight-line-speculation-mitigation.patch
queue-5.10/x86-add-magic-amd-return-thunk.patch
queue-5.10/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch
queue-5.10/x86-alternatives-optimize-optimize_nops.patch
queue-5.10/x86-objtool-create-.return_sites.patch
queue-5.10/crypto-x86-poly1305-fixup-sls.patch
queue-5.10/x86-alternative-handle-jcc-__x86_indirect_thunk_-reg.patch
queue-5.10/x86-kvm-fix-setcc-emulation-for-return-thunks.patch
queue-5.10/objtool-fix-objtool-regression-on-x32-systems.patch
queue-5.10/x86-alternative-relax-text_poke_bp-constraint.patch
queue-5.10/x86-retpoline-swizzle-retpoline-thunk.patch
queue-5.10/objtool-rework-the-elf_rebuild_reloc_section-logic.patch
queue-5.10/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch
queue-5.10/x86-retpoline-remove-unused-replacement-symbols.patch
queue-5.10/objtool-fix-symbol-creation.patch
queue-5.10/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch
queue-5.10/bpf-x86-respect-x86_feature_retpoline.patch
queue-5.10/objtool-fix-type-of-reloc-addend.patch
queue-5.10/objtool-x86-rewrite-retpoline-thunk-calls.patch
queue-5.10/x86-undo-return-thunk-damage.patch
queue-5.10/x86-prepare-inline-asm-for-straight-line-speculation.patch
queue-5.10/x86-alternative-support-alternative_ternary.patch
queue-5.10/kvm-emulate-fix-setcc-emulation-function-offsets-with-sls.patch
queue-5.10/objtool-handle-per-arch-retpoline-naming.patch
queue-5.10/x86-retpoline-create-a-retpoline-thunk-array.patch
queue-5.10/x86-retpoline-simplify-retpolines.patch
queue-5.10/x86-asm-fix-register-order.patch
queue-5.10/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch
queue-5.10/objtool-add-entry-unret-validation.patch
queue-5.10/objtool-keep-track-of-retpoline-call-sites.patch
queue-5.10/kvm-vmx-convert-launched-argument-to-flags.patch
queue-5.10/objtool-add-elf_create_reloc-helper.patch
queue-5.10/objtool-make-.altinstructions-section-entry-size-consistent.patch
queue-5.10/x86-bpf-use-alternative-ret-encoding.patch
queue-5.10/x86-common-stamp-out-the-stepping-madness.patch
queue-5.10/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch
queue-5.10/x86-bugs-report-intel-retbleed-vulnerability.patch
queue-5.10/bpf-x86-simplify-computing-label-offsets.patch
queue-5.10/x86-cpufeatures-move-retpoline-flags-to-word-11.patch
queue-5.10/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch
queue-5.10/x86-retpoline-use-mfunction-return.patch
queue-5.10/x86-xen-rename-sys-entry-points.patch
queue-5.10/objtool-only-rewrite-unconditional-retpoline-thunk-calls.patch
queue-5.10/x86-bugs-optimize-spec_ctrl-msr-writes.patch
queue-5.10/x86-alternative-optimize-single-byte-nops-at-an-arbitrary-position.patch
queue-5.10/objtool-fix-code-relocs-vs-weak-symbols.patch
queue-5.10/x86-bugs-report-amd-retbleed-vulnerability.patch
queue-5.10/x86-static_call-use-alternative-ret-encoding.patch
queue-5.10/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch
queue-5.10/x86-asm-fixup-odd-gen-for-each-reg.h-usage.patch
queue-5.10/x86-alternative-add-debug-prints-to-apply_retpolines.patch
queue-5.10/objtool-extract-elf_symbol_add.patch
queue-5.10/x86-use-return-thunk-in-asm-code.patch
queue-5.10/objtool-remove-reloc-symbol-type-checks-in-get_alt_entry.patch
queue-5.10/objtool-classify-symbols.patch
queue-5.10/intel_idle-disable-ibrs-during-long-idle.patch
queue-5.10/objtool-correctly-handle-retpoline-thunk-calls.patch
queue-5.10/objtool-fix-.symtab_shndx-handling-for-elf_create_undef_symbol.patch
queue-5.10/x86-retpoline-move-the-retpoline-thunk-declarations-to-nospec-branch.h.patch
queue-5.10/objtool-support-asm-jump-tables.patch
queue-5.10/x86-alternative-implement-.retpoline_sites-support.patch
queue-5.10/objtool-x86-ignore-__x86_indirect_alt_-symbols.patch
queue-5.10/objtool-fix-sls-validation-for-kcov-tail-call-replacement.patch
queue-5.10/x86-alternative-try-inline-spectre_v2-retpoline-amd.patch
queue-5.10/x86-entry-remove-skip_r11rcx.patch
queue-5.10/objtool-explicitly-avoid-self-modifying-code-in-.altinstr_replacement.patch
queue-5.10/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch
queue-5.10/x86-bugs-add-amd-retbleed-boot-parameter.patch
queue-5.10/objtool-create-reloc-sections-implicitly.patch
queue-5.10/x86-entry-add-kernel-ibrs-implementation.patch
queue-5.10/objtool-treat-.text.__x86.-as-noinstr.patch
queue-5.10/x86-lib-atomic64_386_32-rename-things.patch
queue-5.10/objtool-introduce-cfi-hash.patch
queue-5.10/objtool-default-ignore-int3-for-unreachable.patch
queue-5.10/objtool-extract-elf_strtab_concat.patch
queue-5.10/objtool-teach-get_alt_entry-about-more-relocation-types.patch
queue-5.10/objtool-update-retpoline-validation.patch
