This is a note to let you know that I've just added the patch titled
x86: Use -mindirect-branch-cs-prefix for RETPOLINE builds
to the 5.15-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:
x86-use-mindirect-branch-cs-prefix-for-retpoline-builds.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 68cf4f2a72ef8786e6b7af6fd9a89f27ac0f520d Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Fri, 19 Nov 2021 17:50:25 +0100
Subject: x86: Use -mindirect-branch-cs-prefix for RETPOLINE builds
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 68cf4f2a72ef8786e6b7af6fd9a89f27ac0f520d upstream.
In order to further enable commit:
bbe2df3f6b6d ("x86/alternative: Try inline spectre_v2=retpoline,amd")
add the new GCC flag -mindirect-branch-cs-prefix:
https://gcc.gnu.org/g:2196a681d7810ad8b227bf983f38ba716620545e
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952
https://bugs.llvm.org/show_bug.cgi?id=52323
to RETPOLINE=y builds. This should allow fully inlining retpoline,amd
for GCC builds.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20211119165630.276205624@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
Makefile | 1 +
1 file changed, 1 insertion(+)
--- a/Makefile
+++ b/Makefile
@@ -687,6 +687,7 @@ endif
ifdef CONFIG_CC_IS_GCC
RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
+RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix)
RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
endif
ifdef CONFIG_CC_IS_CLANG
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-5.15/x86-bugs-add-amd-retbleed-boot-parameter.patch
queue-5.15/x86-bpf-use-alternative-ret-encoding.patch
queue-5.15/objtool-default-ignore-int3-for-unreachable.patch
queue-5.15/x86-retpoline-cleanup-some-ifdefery.patch
queue-5.15/x86-bugs-enable-stibp-for-jmp2ret.patch
queue-5.15/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch
queue-5.15/x86-retpoline-create-a-retpoline-thunk-array.patch
queue-5.15/tools-arch-x86-sync-the-msr-index.h-copy-with-the-kernel-sources.patch
queue-5.15/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch
queue-5.15/x86-ftrace-use-alternative-ret-encoding.patch
queue-5.15/x86-retpoline-swizzle-retpoline-thunk.patch
queue-5.15/kvm-vmx-flatten-__vmx_vcpu_run.patch
queue-5.15/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch
queue-5.15/x86-alternative-implement-.retpoline_sites-support.patch
queue-5.15/x86-entry-move-push_and_clear_regs-back-into-error_entry.patch
queue-5.15/objtool-re-add-unwind_hint_-save_restore.patch
queue-5.15/x86-retpoline-move-the-retpoline-thunk-declarations-to-nospec-branch.h.patch
queue-5.15/x86-bugs-add-retbleed-ibpb.patch
queue-5.15/x86-asm-fixup-odd-gen-for-each-reg.h-usage.patch
queue-5.15/x86-alternative-handle-jcc-__x86_indirect_thunk_-reg.patch
queue-5.15/objtool-classify-symbols.patch
queue-5.15/tools-headers-cpufeatures-sync-with-the-kernel-sources.patch
queue-5.15/x86-asm-fix-register-order.patch
queue-5.15/intel_idle-disable-ibrs-during-long-idle.patch
queue-5.15/objtool-update-retpoline-validation.patch
queue-5.15/kvm-vmx-fix-ibrs-handling-after-vmexit.patch
queue-5.15/objtool-shrink-struct-instruction.patch
queue-5.15/x86-bugs-optimize-spec_ctrl-msr-writes.patch
queue-5.15/x86-objtool-create-.return_sites.patch
queue-5.15/x86-kvm-fix-fastop_size-when-return-thunks-are-enabled.patch
queue-5.15/x86-xen-add-untrain_ret.patch
queue-5.15/x86-retpoline-use-mfunction-return.patch
queue-5.15/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch
queue-5.15/objtool-treat-.text.__x86.-as-noinstr.patch
queue-5.15/x86-retpoline-remove-unused-replacement-symbols.patch
queue-5.15/x86-add-magic-amd-return-thunk.patch
queue-5.15/x86-xen-rename-sys-entry-points.patch
queue-5.15/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch
queue-5.15/x86-kvm-fix-setcc-emulation-for-return-thunks.patch
queue-5.15/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch
queue-5.15/x86-use-return-thunk-in-asm-code.patch
queue-5.15/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch
queue-5.15/x86-use-mindirect-branch-cs-prefix-for-retpoline-builds.patch
queue-5.15/x86-static_call-use-alternative-ret-encoding.patch
queue-5.15/objtool-explicitly-avoid-self-modifying-code-in-.altinstr_replacement.patch
queue-5.15/x86-cpu-amd-add-spectral-chicken.patch
queue-5.15/x86-cpufeatures-move-retpoline-flags-to-word-11.patch
queue-5.15/x86-entry-avoid-very-early-ret.patch
queue-5.15/x86-vsyscall_emu-64-don-t-use-ret-in-vsyscall-emulation.patch
queue-5.15/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch
queue-5.15/x86-bugs-report-amd-retbleed-vulnerability.patch
queue-5.15/efi-x86-use-naked-ret-on-mixed-mode-call-wrapper.patch
queue-5.15/objtool-x86-replace-alternatives-with-.retpoline_sites.patch
queue-5.15/x86-sev-avoid-using-__x86_return_thunk.patch
queue-5.15/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch
queue-5.15/x86-entry-remove-skip_r11rcx.patch
queue-5.15/x86-undo-return-thunk-damage.patch
queue-5.15/bpf-x86-respect-x86_feature_retpoline.patch
queue-5.15/objtool-introduce-cfi-hash.patch
queue-5.15/x86-common-stamp-out-the-stepping-madness.patch
queue-5.15/x86-bugs-report-intel-retbleed-vulnerability.patch
queue-5.15/bpf-x86-simplify-computing-label-offsets.patch
queue-5.15/x86-alternative-try-inline-spectre_v2-retpoline-amd.patch
queue-5.15/um-add-missing-apply_returns.patch
queue-5.15/x86-kvm-vmx-make-noinstr-clean.patch
queue-5.15/x86-retbleed-add-fine-grained-kconfig-knobs.patch
queue-5.15/x86-alternative-add-debug-prints-to-apply_retpolines.patch
queue-5.15/kvm-vmx-convert-launched-argument-to-flags.patch
queue-5.15/x86-entry-add-kernel-ibrs-implementation.patch
queue-5.15/objtool-add-entry-unret-validation.patch
