This is a note to let you know that I've just added the patch titled
x86/speculation: Change FILL_RETURN_BUFFER to work with objtool
to the 5.4-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-speculation-change-fill_return_buffer-to-work-with-objtool.patch
and it can be found in the queue-5.4 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 Wed Oct 5 12:28:43 PM CEST 2022
From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Date: Mon, 3 Oct 2022 10:10:19 -0300
Subject: x86/speculation: Change FILL_RETURN_BUFFER to work with objtool
To: stable@xxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx, kvm@xxxxxxxxxxxxxxx, bp@xxxxxxxxx, pbonzini@xxxxxxxxxx, peterz@xxxxxxxxxxxxx, jpoimboe@xxxxxxxxxx
Message-ID: <20221003131038.12645-19-cascardo@xxxxxxxxxxxxx>
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit 089dd8e53126ebaf506e2dc0bf89d652c36bfc12 upstream.
Change FILL_RETURN_BUFFER so that objtool groks it and can generate
correct ORC unwind information.
- Since ORC is alternative invariant; that is, all alternatives
should have the same ORC entries, the __FILL_RETURN_BUFFER body
can not be part of an alternative.
Therefore, move it out of the alternative and keep the alternative
as a sort of jump_label around it.
- Use the ANNOTATE_INTRA_FUNCTION_CALL annotation to white-list
these 'funny' call instructions to nowhere.
- Use UNWIND_HINT_EMPTY to 'fill' the speculation traps, otherwise
objtool will consider them unreachable.
- Move the RSP adjustment into the loop, such that the loop has a
deterministic stack layout.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200428191700.032079304@xxxxxxxxxxxxx
[cascardo: fixup because of backport of ba6e31af2be96c4d0536f2152ed6f7b6c11bca47 ("x86/speculation: Add LFENCE to RSB fill sequence")]
[cascardo: no intra-function call validation support]
[cascardo: avoid UNWIND_HINT_EMPTY because of svm]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/nospec-branch.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -4,11 +4,13 @@
#define _ASM_X86_NOSPEC_BRANCH_H_
#include <linux/static_key.h>
+#include <linux/frame.h>
#include <asm/alternative.h>
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
#include <asm/msr-index.h>
+#include <asm/unwind_hints.h>
/*
* This should be used immediately before a retpoline alternative. It tells
@@ -60,9 +62,9 @@
lfence; \
jmp 775b; \
774: \
+ add $(BITS_PER_LONG/8) * 2, sp; \
dec reg; \
jnz 771b; \
- add $(BITS_PER_LONG/8) * nr, sp; \
/* barrier for jnz misprediction */ \
lfence;
#else
@@ -154,10 +156,8 @@
*/
.macro FILL_RETURN_BUFFER reg:req nr:req ftr:req
#ifdef CONFIG_RETPOLINE
- ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE "jmp .Lskip_rsb_\@", \
- __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \
- \ftr
+ ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr
+ __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)
.Lskip_rsb_\@:
#endif
.endm
Patches currently in stable-queue which might be from cascardo@xxxxxxxxxxxxx are
queue-5.4/x86-speculation-disable-rrsba-behavior.patch
queue-5.4/kvm-vmx-flatten-__vmx_vcpu_run.patch
queue-5.4/x86-kvm-vmx-make-noinstr-clean.patch
queue-5.4/revert-x86-speculation-add-rsb-vm-exit-protections.patch
queue-5.4/kvm-vmx-fix-ibrs-handling-after-vmexit.patch
queue-5.4/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch
queue-5.4/kvm-nvmx-use-__vmx_vcpu_run-in-nested_vmx_check_vmentry_hw.patch
queue-5.4/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch
queue-5.4/x86-cpu-amd-enumerate-btc_no.patch
queue-5.4/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch
queue-5.4/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch
queue-5.4/x86-cpu-add-consistent-cpu-match-macros.patch
queue-5.4/x86-speculation-remove-x86_spec_ctrl_mask.patch
queue-5.4/x86-bugs-add-cannon-lake-to-retbleed-affected-cpu-list.patch
queue-5.4/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch
queue-5.4/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch
queue-5.4/x86-cpu-add-a-steppings-field-to-struct-x86_cpu_id.patch
queue-5.4/kvm-vmx-convert-launched-argument-to-flags.patch
queue-5.4/x86-common-stamp-out-the-stepping-madness.patch
queue-5.4/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch
queue-5.4/x86-bugs-report-intel-retbleed-vulnerability.patch
queue-5.4/x86-speculation-change-fill_return_buffer-to-work-with-objtool.patch
queue-5.4/x86-cpufeatures-move-retpoline-flags-to-word-11.patch
queue-5.4/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch
queue-5.4/kvm-vmx-use-test-reg-reg-instead-of-cmp-0-reg-in-vmenter.s.patch
queue-5.4/x86-bugs-optimize-spec_ctrl-msr-writes.patch
queue-5.4/x86-bugs-report-amd-retbleed-vulnerability.patch
queue-5.4/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch
queue-5.4/intel_idle-disable-ibrs-during-long-idle.patch
queue-5.4/x86-speculation-use-declare_per_cpu-for-x86_spec_ctrl_current.patch
queue-5.4/x86-entry-remove-skip_r11rcx.patch
queue-5.4/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch
queue-5.4/x86-devicetable-move-x86-specific-macro-out-of-generic-code.patch
queue-5.4/x86-bugs-add-amd-retbleed-boot-parameter.patch
queue-5.4/x86-entry-add-kernel-ibrs-implementation.patch
queue-5.4/revert-x86-cpu-add-a-steppings-field-to-struct-x86_cpu_id.patch
queue-5.4/x86-speculation-add-rsb-vm-exit-protections.patch
