This is a note to let you know that I've just added the patch titled
x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-mm-sme-objtool-annotate-indirect-call-in-sme_encrypt_execute.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 531bb52a869a9c6e08c8d17ba955fcbfc18037ad Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Tue, 23 Jan 2018 16:18:50 +0100
Subject: x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()
From: Peter Zijlstra <peterz(a)infradead.org>
commit 531bb52a869a9c6e08c8d17ba955fcbfc18037ad upstream.
This is boot code and thus Spectre-safe: we run this _way_ before userspace
comes along to have a chance to poison our branch predictor.
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Borislav Petkov <bp(a)suse.de>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Tom Lendacky <thomas.lendacky(a)amd.com>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/mm/mem_encrypt_boot.S | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/mm/mem_encrypt_boot.S
+++ b/arch/x86/mm/mem_encrypt_boot.S
@@ -15,6 +15,7 @@
#include <asm/page.h>
#include <asm/processor-flags.h>
#include <asm/msr-index.h>
+#include <asm/nospec-branch.h>
.text
.code64
@@ -59,6 +60,7 @@ ENTRY(sme_encrypt_execute)
movq %rax, %r8 /* Workarea encryption routine */
addq $PAGE_SIZE, %r8 /* Workarea intermediate copy buffer */
+ ANNOTATE_RETPOLINE_SAFE
call *%rax /* Call the encryption routine */
pop %r12
Patches currently in stable-queue which might be from peterz(a)infradead.org are
queue-4.15/x86-boot-objtool-annotate-indirect-jump-in-secondary_startup_64.patch
queue-4.15/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.15/x86-ldt-avoid-warning-in-32-bit-builds-with-older-gcc.patch
queue-4.15/x86-entry-reduce-the-code-footprint-of-the-idtentry-macro.patch
queue-4.15/bug-use-pb-in-bug-and-stack-protector-failure.patch
queue-4.15/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.15/nospec-include-asm-barrier.h-dependency.patch
queue-4.15/x86-mm-remove-stale-comment-about-kmemcheck.patch
queue-4.15/x86-mm-sme-objtool-annotate-indirect-call-in-sme_encrypt_execute.patch
queue-4.15/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.15/x86-asm-improve-how-gen_-_suffixed_rmwcc-specify-clobbers.patch
queue-4.15/x86-64-realmode-add-instruction-suffix.patch
queue-4.15/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
queue-4.15/x86-paravirt-objtool-annotate-indirect-calls.patch
queue-4.15/x86-entry-64-use-xorl-for-faster-register-clearing.patch
queue-4.15/nospec-kill-array_index_nospec_mask_check.patch
queue-4.15/lib-bug.c-exclude-non-bug-warn-exceptions-from-report_bug.patch
queue-4.15/x86-io-apic-avoid-warning-in-32-bit-builds.patch
This is a note to let you know that I've just added the patch titled
x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-boot-objtool-annotate-indirect-jump-in-secondary_startup_64.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From bd89004f6305cbf7352238f61da093207ee518d6 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Tue, 16 Jan 2018 10:38:09 +0100
Subject: x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
From: Peter Zijlstra <peterz(a)infradead.org>
commit bd89004f6305cbf7352238f61da093207ee518d6 upstream.
The objtool retpoline validation found this indirect jump. Seeing how
it's on CPU bringup before we run userspace it should be safe, annotate
it.
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Reviewed-by: David Woodhouse <dwmw(a)amazon.co.uk>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/head_64.S | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -23,6 +23,7 @@
#include <asm/nops.h>
#include "../entry/calling.h"
#include <asm/export.h>
+#include <asm/nospec-branch.h>
#ifdef CONFIG_PARAVIRT
#include <asm/asm-offsets.h>
@@ -134,6 +135,7 @@ ENTRY(secondary_startup_64)
/* Ensure I am executing from virtual addresses */
movq $1f, %rax
+ ANNOTATE_RETPOLINE_SAFE
jmp *%rax
1:
UNWIND_HINT_EMPTY
Patches currently in stable-queue which might be from peterz(a)infradead.org are
queue-4.15/x86-boot-objtool-annotate-indirect-jump-in-secondary_startup_64.patch
queue-4.15/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.15/x86-ldt-avoid-warning-in-32-bit-builds-with-older-gcc.patch
queue-4.15/x86-entry-reduce-the-code-footprint-of-the-idtentry-macro.patch
queue-4.15/bug-use-pb-in-bug-and-stack-protector-failure.patch
queue-4.15/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.15/nospec-include-asm-barrier.h-dependency.patch
queue-4.15/x86-mm-remove-stale-comment-about-kmemcheck.patch
queue-4.15/x86-mm-sme-objtool-annotate-indirect-call-in-sme_encrypt_execute.patch
queue-4.15/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.15/x86-asm-improve-how-gen_-_suffixed_rmwcc-specify-clobbers.patch
queue-4.15/x86-64-realmode-add-instruction-suffix.patch
queue-4.15/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
queue-4.15/x86-paravirt-objtool-annotate-indirect-calls.patch
queue-4.15/x86-entry-64-use-xorl-for-faster-register-clearing.patch
queue-4.15/nospec-kill-array_index_nospec_mask_check.patch
queue-4.15/lib-bug.c-exclude-non-bug-warn-exceptions-from-report_bug.patch
queue-4.15/x86-io-apic-avoid-warning-in-32-bit-builds.patch
This is a note to let you know that I've just added the patch titled
x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-mm-sme-objtool-annotate-indirect-call-in-sme_encrypt_execute.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 531bb52a869a9c6e08c8d17ba955fcbfc18037ad Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Tue, 23 Jan 2018 16:18:50 +0100
Subject: x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute()
From: Peter Zijlstra <peterz(a)infradead.org>
commit 531bb52a869a9c6e08c8d17ba955fcbfc18037ad upstream.
This is boot code and thus Spectre-safe: we run this _way_ before userspace
comes along to have a chance to poison our branch predictor.
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Borislav Petkov <bp(a)suse.de>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Tom Lendacky <thomas.lendacky(a)amd.com>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/mm/mem_encrypt_boot.S | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/mm/mem_encrypt_boot.S
+++ b/arch/x86/mm/mem_encrypt_boot.S
@@ -15,6 +15,7 @@
#include <asm/page.h>
#include <asm/processor-flags.h>
#include <asm/msr-index.h>
+#include <asm/nospec-branch.h>
.text
.code64
@@ -59,6 +60,7 @@ ENTRY(sme_encrypt_execute)
movq %rax, %r8 /* Workarea encryption routine */
addq $PAGE_SIZE, %r8 /* Workarea intermediate copy buffer */
+ ANNOTATE_RETPOLINE_SAFE
call *%rax /* Call the encryption routine */
pop %r12
Patches currently in stable-queue which might be from peterz(a)infradead.org are
queue-4.14/x86-boot-objtool-annotate-indirect-jump-in-secondary_startup_64.patch
queue-4.14/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.14/x86-ldt-avoid-warning-in-32-bit-builds-with-older-gcc.patch
queue-4.14/x86-entry-reduce-the-code-footprint-of-the-idtentry-macro.patch
queue-4.14/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.14/nospec-include-asm-barrier.h-dependency.patch
queue-4.14/x86-mm-remove-stale-comment-about-kmemcheck.patch
queue-4.14/x86-mm-sme-objtool-annotate-indirect-call-in-sme_encrypt_execute.patch
queue-4.14/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.14/x86-asm-improve-how-gen_-_suffixed_rmwcc-specify-clobbers.patch
queue-4.14/x86-64-realmode-add-instruction-suffix.patch
queue-4.14/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
queue-4.14/x86-paravirt-objtool-annotate-indirect-calls.patch
queue-4.14/x86-entry-64-use-xorl-for-faster-register-clearing.patch
queue-4.14/nospec-kill-array_index_nospec_mask_check.patch
queue-4.14/lib-bug.c-exclude-non-bug-warn-exceptions-from-report_bug.patch
This is a note to let you know that I've just added the patch titled
x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-boot-objtool-annotate-indirect-jump-in-secondary_startup_64.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From bd89004f6305cbf7352238f61da093207ee518d6 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Tue, 16 Jan 2018 10:38:09 +0100
Subject: x86/boot, objtool: Annotate indirect jump in secondary_startup_64()
From: Peter Zijlstra <peterz(a)infradead.org>
commit bd89004f6305cbf7352238f61da093207ee518d6 upstream.
The objtool retpoline validation found this indirect jump. Seeing how
it's on CPU bringup before we run userspace it should be safe, annotate
it.
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Reviewed-by: David Woodhouse <dwmw(a)amazon.co.uk>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/head_64.S | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -23,6 +23,7 @@
#include <asm/nops.h>
#include "../entry/calling.h"
#include <asm/export.h>
+#include <asm/nospec-branch.h>
#ifdef CONFIG_PARAVIRT
#include <asm/asm-offsets.h>
@@ -134,6 +135,7 @@ ENTRY(secondary_startup_64)
/* Ensure I am executing from virtual addresses */
movq $1f, %rax
+ ANNOTATE_RETPOLINE_SAFE
jmp *%rax
1:
UNWIND_HINT_EMPTY
Patches currently in stable-queue which might be from peterz(a)infradead.org are
queue-4.14/x86-boot-objtool-annotate-indirect-jump-in-secondary_startup_64.patch
queue-4.14/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.14/x86-ldt-avoid-warning-in-32-bit-builds-with-older-gcc.patch
queue-4.14/x86-entry-reduce-the-code-footprint-of-the-idtentry-macro.patch
queue-4.14/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.14/nospec-include-asm-barrier.h-dependency.patch
queue-4.14/x86-mm-remove-stale-comment-about-kmemcheck.patch
queue-4.14/x86-mm-sme-objtool-annotate-indirect-call-in-sme_encrypt_execute.patch
queue-4.14/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.14/x86-asm-improve-how-gen_-_suffixed_rmwcc-specify-clobbers.patch
queue-4.14/x86-64-realmode-add-instruction-suffix.patch
queue-4.14/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
queue-4.14/x86-paravirt-objtool-annotate-indirect-calls.patch
queue-4.14/x86-entry-64-use-xorl-for-faster-register-clearing.patch
queue-4.14/nospec-kill-array_index_nospec_mask_check.patch
queue-4.14/lib-bug.c-exclude-non-bug-warn-exceptions-from-report_bug.patch
This is a note to let you know that I've just added the patch titled
x86/speculation, objtool: Annotate indirect calls/jumps for objtool
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 9e0e3c5130e949c389caabc8033e9799b129e429 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Wed, 17 Jan 2018 22:34:34 +0100
Subject: x86/speculation, objtool: Annotate indirect calls/jumps for objtool
From: Peter Zijlstra <peterz(a)infradead.org>
commit 9e0e3c5130e949c389caabc8033e9799b129e429 upstream.
Annotate the indirect calls/jumps in the CALL_NOSPEC/JUMP_NOSPEC
alternatives.
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Reviewed-by: David Woodhouse <dwmw(a)amazon.co.uk>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 27 +++++++++++++++++++++++----
1 file changed, 23 insertions(+), 4 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -68,6 +68,18 @@
.endm
/*
+ * This should be used immediately before an indirect jump/call. It tells
+ * objtool the subsequent indirect jump/call is vouched safe for retpoline
+ * builds.
+ */
+.macro ANNOTATE_RETPOLINE_SAFE
+ .Lannotate_\@:
+ .pushsection .discard.retpoline_safe
+ _ASM_PTR .Lannotate_\@
+ .popsection
+.endm
+
+/*
* These are the bare retpoline primitives for indirect jmp and call.
* Do not use these directly; they only exist to make the ALTERNATIVE
* invocation below less ugly.
@@ -103,9 +115,9 @@
.macro JMP_NOSPEC reg:req
#ifdef CONFIG_RETPOLINE
ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE_2 __stringify(jmp *\reg), \
+ ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg), \
__stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \
- __stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
+ __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
#else
jmp *\reg
#endif
@@ -114,9 +126,9 @@
.macro CALL_NOSPEC reg:req
#ifdef CONFIG_RETPOLINE
ANNOTATE_NOSPEC_ALTERNATIVE
- ALTERNATIVE_2 __stringify(call *\reg), \
+ ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg), \
__stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\
- __stringify(lfence; call *\reg), X86_FEATURE_RETPOLINE_AMD
+ __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RETPOLINE_AMD
#else
call *\reg
#endif
@@ -144,6 +156,12 @@
".long 999b - .\n\t" \
".popsection\n\t"
+#define ANNOTATE_RETPOLINE_SAFE \
+ "999:\n\t" \
+ ".pushsection .discard.retpoline_safe\n\t" \
+ _ASM_PTR " 999b\n\t" \
+ ".popsection\n\t"
+
#if defined(CONFIG_X86_64) && defined(RETPOLINE)
/*
@@ -153,6 +171,7 @@
# define CALL_NOSPEC \
ANNOTATE_NOSPEC_ALTERNATIVE \
ALTERNATIVE( \
+ ANNOTATE_RETPOLINE_SAFE \
"call *%[thunk_target]\n", \
"call __x86_indirect_thunk_%V[thunk_target]\n", \
X86_FEATURE_RETPOLINE)
Patches currently in stable-queue which might be from peterz(a)infradead.org are
queue-4.9/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.9/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.9/nospec-include-asm-barrier.h-dependency.patch
queue-4.9/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.9/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
queue-4.9/nospec-kill-array_index_nospec_mask_check.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline: Support retpoline builds with Clang
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86-retpoline-support-retpoline-builds-with-clang.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
>From 87358710c1fb4f1bf96bbe2349975ff9953fc9b2 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Mon, 19 Feb 2018 10:50:57 +0000
Subject: x86/retpoline: Support retpoline builds with Clang
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 87358710c1fb4f1bf96bbe2349975ff9953fc9b2 upstream.
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Reviewed-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: arjan.van.de.ven(a)intel.com
Cc: bp(a)alien8.de
Cc: dave.hansen(a)intel.com
Cc: jmattson(a)google.com
Cc: karahmed(a)amazon.de
Cc: kvm(a)vger.kernel.org
Cc: pbonzini(a)redhat.com
Cc: rkrcmar(a)redhat.com
Link: http://lkml.kernel.org/r/1519037457-7643-5-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/Makefile | 5 ++++-
include/linux/compiler-clang.h | 5 +++++
include/linux/compiler-gcc.h | 4 ++++
include/linux/init.h | 8 ++++----
4 files changed, 17 insertions(+), 5 deletions(-)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -184,7 +184,10 @@ KBUILD_AFLAGS += $(mflags-y)
# Avoid indirect branches in kernel to deal with Spectre
ifdef CONFIG_RETPOLINE
- RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
+ RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
+ RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
+
+ RETPOLINE_CFLAGS += $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
ifneq ($(RETPOLINE_CFLAGS),)
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
endif
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -15,3 +15,8 @@
* with any version that can compile the kernel
*/
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
+/* Clang doesn't have a way to turn it off per-function, yet. */
+#ifdef __noretpoline
+#undef __noretpoline
+#endif
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -88,6 +88,10 @@
#define __weak __attribute__((weak))
#define __alias(symbol) __attribute__((alias(#symbol)))
+#ifdef RETPOLINE
+#define __noretpoline __attribute__((indirect_branch("keep")))
+#endif
+
/*
* it doesn't make sense on ARM (currently the only user of __naked)
* to trace naked functions because then mcount is called without
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -5,10 +5,10 @@
#include <linux/types.h>
/* Built-in __init functions needn't be compiled with retpoline */
-#if defined(RETPOLINE) && !defined(MODULE)
-#define __noretpoline __attribute__((indirect_branch("keep")))
+#if defined(__noretpoline) && !defined(MODULE)
+#define __noinitretpoline __noretpoline
#else
-#define __noretpoline
+#define __noinitretpoline
#endif
/* These macros are used to mark some functions or
@@ -46,7 +46,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
-#define __init __section(.init.text) __cold notrace __latent_entropy __noretpoline
+#define __init __section(.init.text) __cold notrace __latent_entropy __noinitretpoline
#define __initdata __section(.init.data)
#define __initconst __section(.init.rodata)
#define __exitdata __section(.exit.data)
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.9/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.9/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.9/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.9/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch