This is a note to let you know that I've just added the patch titled
nospec: Include <asm/barrier.h> dependency
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:
nospec-include-asm-barrier.h-dependency.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 eb6174f6d1be16b19cfa43dac296bfed003ce1a6 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams(a)intel.com>
Date: Fri, 16 Feb 2018 13:20:54 -0800
Subject: nospec: Include <asm/barrier.h> dependency
From: Dan Williams <dan.j.williams(a)intel.com>
commit eb6174f6d1be16b19cfa43dac296bfed003ce1a6 upstream.
The nospec.h header expects the per-architecture header file
<asm/barrier.h> to optionally define array_index_mask_nospec(). Include
that dependency to prevent inadvertent fallback to the default
array_index_mask_nospec() implementation.
The default implementation may not provide a full mitigation
on architectures that perform data value speculation.
Reported-by: Christian Borntraeger <borntraeger(a)de.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.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: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Will Deacon <will.deacon(a)arm.com>
Cc: linux-arch(a)vger.kernel.org
Link: http://lkml.kernel.org/r/151881605404.17395.1341935530792574707.stgit@dwill…
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
include/linux/nospec.h | 1 +
1 file changed, 1 insertion(+)
--- a/include/linux/nospec.h
+++ b/include/linux/nospec.h
@@ -5,6 +5,7 @@
#ifndef _LINUX_NOSPEC_H
#define _LINUX_NOSPEC_H
+#include <asm/barrier.h>
/**
* array_index_mask_nospec() - generate a ~0 mask when index < size, 0 otherwise
Patches currently in stable-queue which might be from dan.j.williams(a)intel.com are
queue-4.15/x86-entry-reduce-the-code-footprint-of-the-idtentry-macro.patch
queue-4.15/nospec-include-asm-barrier.h-dependency.patch
queue-4.15/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.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
This is a note to let you know that I've just added the patch titled
MIPS: CPC: Map registers using DT in mips_cpc_default_phys_base()
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:
mips-cpc-map-registers-using-dt-in-mips_cpc_default_phys_base.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 791412dafbbfd860e78983d45cf71db603a82f67 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton(a)mips.com>
Date: Fri, 19 Jan 2018 16:40:49 +0100
Subject: MIPS: CPC: Map registers using DT in mips_cpc_default_phys_base()
From: Paul Burton <paul.burton(a)mips.com>
commit 791412dafbbfd860e78983d45cf71db603a82f67 upstream.
Reading mips_cpc_base value from the DT allows each platform to
define it according to its needs. This is especially convenient
for MIPS_GENERIC kernel where this kind of information should be
determined in runtime.
Use mti,mips-cpc compatible string with just a reg property to
specify the register location for your platform.
Signed-off-by: Paul Burton <paul.burton(a)mips.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic(a)mips.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic(a)mips.com>
Cc: linux-mips(a)linux-mips.org
Cc: Ralf Baechle <ralf(a)linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/18513/
Signed-off-by: James Hogan <jhogan(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/mips/kernel/mips-cpc.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/arch/mips/kernel/mips-cpc.c
+++ b/arch/mips/kernel/mips-cpc.c
@@ -10,6 +10,8 @@
#include <linux/errno.h>
#include <linux/percpu.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/spinlock.h>
#include <asm/mips-cps.h>
@@ -22,6 +24,17 @@ static DEFINE_PER_CPU_ALIGNED(unsigned l
phys_addr_t __weak mips_cpc_default_phys_base(void)
{
+ struct device_node *cpc_node;
+ struct resource res;
+ int err;
+
+ cpc_node = of_find_compatible_node(of_root, NULL, "mti,mips-cpc");
+ if (cpc_node) {
+ err = of_address_to_resource(cpc_node, 0, &res);
+ if (!err)
+ return res.start;
+ }
+
return 0;
}
Patches currently in stable-queue which might be from paul.burton(a)mips.com are
queue-4.15/mips-cpc-map-registers-using-dt-in-mips_cpc_default_phys_base.patch
queue-4.15/dt-bindings-document-mti-mips-cpc-binding.patch
This is a note to let you know that I've just added the patch titled
dt-bindings: Document mti,mips-cpc binding
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:
dt-bindings-document-mti-mips-cpc-binding.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 aece34cd576c7625181b0488a8129c1e165355f7 Mon Sep 17 00:00:00 2001
From: Paul Burton <paul.burton(a)mips.com>
Date: Fri, 19 Jan 2018 16:40:48 +0100
Subject: dt-bindings: Document mti,mips-cpc binding
From: Paul Burton <paul.burton(a)mips.com>
commit aece34cd576c7625181b0488a8129c1e165355f7 upstream.
Document a binding for the MIPS Cluster Power Controller (CPC) that
allows the device tree to specify where the CPC registers are located.
Signed-off-by: Paul Burton <paul.burton(a)mips.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic(a)mips.com>
Reviewed-by: Rob Herring <robh(a)kernel.org>
Cc: linux-mips(a)linux-mips.org
Cc: devicetree(a)vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/18512/
Signed-off-by: James Hogan <jhogan(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
Documentation/devicetree/bindings/power/mti,mips-cpc.txt | 8 ++++++++
MAINTAINERS | 1 +
2 files changed, 9 insertions(+)
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/mti,mips-cpc.txt
@@ -0,0 +1,8 @@
+Binding for MIPS Cluster Power Controller (CPC).
+
+This binding allows a system to specify where the CPC registers are
+located.
+
+Required properties:
+compatible : Should be "mti,mips-cpc".
+regs: Should describe the address & size of the CPC register region.
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9107,6 +9107,7 @@ MIPS GENERIC PLATFORM
M: Paul Burton <paul.burton(a)mips.com>
L: linux-mips(a)linux-mips.org
S: Supported
+F: Documentation/devicetree/bindings/power/mti,mips-cpc.txt
F: arch/mips/generic/
F: arch/mips/tools/generic-board-config.sh
Patches currently in stable-queue which might be from paul.burton(a)mips.com are
queue-4.15/mips-cpc-map-registers-using-dt-in-mips_cpc_default_phys_base.patch
queue-4.15/dt-bindings-document-mti-mips-cpc-binding.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 4.14-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-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.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 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-4.14/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/bug-use-pb-in-bug-and-stack-protector-failure.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-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-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/retpoline: Support retpoline builds with Clang
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-retpoline-support-retpoline-builds-with-clang.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 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
@@ -232,7 +232,10 @@ KBUILD_CFLAGS += -fno-asynchronous-unwin
# 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
@@ -19,3 +19,8 @@
#define randomized_struct_fields_start struct {
#define randomized_struct_fields_end };
+
+/* 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
@@ -93,6 +93,10 @@
#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
@@ -6,10 +6,10 @@
#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
@@ -47,7 +47,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
-#define __init __section(.init.text) __cold __inittrace __latent_entropy __noretpoline
+#define __init __section(.init.text) __cold __inittrace __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-4.14/x86-retpoline-support-retpoline-builds-with-clang.patch
queue-4.14/revert-x86-retpoline-simplify-vmexit_fill_rsb.patch
queue-4.14/x86-speculation-use-ibrs-if-available-before-calling-into-firmware.patch
queue-4.14/x86-speculation-objtool-annotate-indirect-calls-jumps-for-objtool.patch
This is a note to let you know that I've just added the patch titled
x86/mm: Remove stale comment about KMEMCHECK
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-remove-stale-comment-about-kmemcheck.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 3b3a9268bba62b35a29bafe0931715b1725fdf26 Mon Sep 17 00:00:00 2001
From: Jann Horn <jannh(a)google.com>
Date: Mon, 19 Feb 2018 18:50:39 +0100
Subject: x86/mm: Remove stale comment about KMEMCHECK
From: Jann Horn <jannh(a)google.com>
commit 3b3a9268bba62b35a29bafe0931715b1725fdf26 upstream.
This comment referred to a conditional call to kmemcheck_hide() that was
here until commit 4950276672fc ("kmemcheck: remove annotations").
Now that kmemcheck has been removed, it doesn't make sense anymore.
Signed-off-by: Jann Horn <jannh(a)google.com>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Brian Gerst <brgerst(a)gmail.com>
Cc: Denys Vlasenko <dvlasenk(a)redhat.com>
Cc: H. Peter Anvin <hpa(a)zytor.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Link: http://lkml.kernel.org/r/20180219175039.253089-1-jannh@google.com
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/mm/fault.c | 4 ----
1 file changed, 4 deletions(-)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1252,10 +1252,6 @@ __do_page_fault(struct pt_regs *regs, un
tsk = current;
mm = tsk->mm;
- /*
- * Detect and handle instructions that would cause a page fault for
- * both a tracked kernel page and a userspace page.
- */
prefetchw(&mm->mmap_sem);
if (unlikely(kmmio_fault(regs, address)))
Patches currently in stable-queue which might be from jannh(a)google.com are
queue-4.14/x86-mm-remove-stale-comment-about-kmemcheck.patch
This is a note to let you know that I've just added the patch titled
x86/LDT: Avoid warning in 32-bit builds with older gcc
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-ldt-avoid-warning-in-32-bit-builds-with-older-gcc.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 f2f18b16c779978ece4a04f304a92ff9ac8fbce5 Mon Sep 17 00:00:00 2001
From: Jan Beulich <JBeulich(a)suse.com>
Date: Mon, 19 Feb 2018 07:52:10 -0700
Subject: x86/LDT: Avoid warning in 32-bit builds with older gcc
From: Jan Beulich <JBeulich(a)suse.com>
commit f2f18b16c779978ece4a04f304a92ff9ac8fbce5 upstream.
BUG() doesn't always imply "no return", and hence should be followed by
a return statement even if that's obviously (to a human) unreachable.
Signed-off-by: Jan Beulich <jbeulich(a)suse.com>
Acked-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Brian Gerst <brgerst(a)gmail.com>
Cc: Denys Vlasenko <dvlasenk(a)redhat.com>
Cc: H. Peter Anvin <hpa(a)zytor.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Link: http://lkml.kernel.org/r/5A8AF2AA02000078001A91E9@prv-mh.provo.novell.com
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/mmu_context.h | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -74,6 +74,7 @@ static inline void *ldt_slot_va(int slot
return (void *)(LDT_BASE_ADDR + LDT_SLOT_STRIDE * slot);
#else
BUG();
+ return (void *)fix_to_virt(FIX_HOLE);
#endif
}
Patches currently in stable-queue which might be from JBeulich(a)suse.com are
queue-4.14/x86-ldt-avoid-warning-in-32-bit-builds-with-older-gcc.patch
queue-4.14/x86-asm-improve-how-gen_-_suffixed_rmwcc-specify-clobbers.patch
queue-4.14/x86-64-realmode-add-instruction-suffix.patch
This is a note to let you know that I've just added the patch titled
x86/entry: Reduce the code footprint of the 'idtentry' macro
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-entry-reduce-the-code-footprint-of-the-idtentry-macro.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 9e809d15d6b692fa061d74be7aaab1c79f6784b8 Mon Sep 17 00:00:00 2001
From: Dominik Brodowski <linux(a)dominikbrodowski.net>
Date: Wed, 14 Feb 2018 18:59:23 +0100
Subject: x86/entry: Reduce the code footprint of the 'idtentry' macro
From: Dominik Brodowski <linux(a)dominikbrodowski.net>
commit 9e809d15d6b692fa061d74be7aaab1c79f6784b8 upstream.
Play a little trick in the generic PUSH_AND_CLEAR_REGS macro
to insert the GP registers "above" the original return address.
This allows us to (re-)insert the macro in error_entry() and
paranoid_entry() and to remove it from the idtentry macro. This
reduces the static footprint significantly:
text data bss dec hex filename
24307 0 0 24307 5ef3 entry_64.o-orig
20987 0 0 20987 51fb entry_64.o
Co-developed-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux(a)dominikbrodowski.net>
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: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Link: http://lkml.kernel.org/r/20180214175924.23065-2-linux@dominikbrodowski.net
[ Small tweaks to comments. ]
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/entry/calling.h | 11 ++++++++++-
arch/x86/entry/entry_64.S | 18 ++++++++----------
2 files changed, 18 insertions(+), 11 deletions(-)
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -97,7 +97,7 @@ For 32-bit we have the following convent
#define SIZEOF_PTREGS 21*8
-.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax
+.macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax save_ret=0
/*
* Push registers and sanitize registers of values that a
* speculation attack might otherwise want to exploit. The
@@ -105,8 +105,14 @@ For 32-bit we have the following convent
* could be put to use in a speculative execution gadget.
* Interleave XOR with PUSH for better uop scheduling:
*/
+ .if \save_ret
+ pushq %rsi /* pt_regs->si */
+ movq 8(%rsp), %rsi /* temporarily store the return address in %rsi */
+ movq %rdi, 8(%rsp) /* pt_regs->di (overwriting original return address) */
+ .else
pushq %rdi /* pt_regs->di */
pushq %rsi /* pt_regs->si */
+ .endif
pushq \rdx /* pt_regs->dx */
pushq %rcx /* pt_regs->cx */
pushq \rax /* pt_regs->ax */
@@ -131,6 +137,9 @@ For 32-bit we have the following convent
pushq %r15 /* pt_regs->r15 */
xorq %r15, %r15 /* nospec r15*/
UNWIND_HINT_REGS
+ .if \save_ret
+ pushq %rsi /* return address on top of stack */
+ .endif
.endm
.macro POP_REGS pop_rdi=1 skip_r11rcx=0
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -867,12 +867,8 @@ ENTRY(\sym)
pushq $-1 /* ORIG_RAX: no syscall to restart */
.endif
- /* Save all registers in pt_regs */
- PUSH_AND_CLEAR_REGS
- ENCODE_FRAME_POINTER
-
.if \paranoid < 2
- testb $3, CS(%rsp) /* If coming from userspace, switch stacks */
+ testb $3, CS-ORIG_RAX(%rsp) /* If coming from userspace, switch stacks */
jnz .Lfrom_usermode_switch_stack_\@
.endif
@@ -1117,13 +1113,15 @@ idtentry machine_check do_mce has_err
#endif
/*
- * Switch gs if needed.
+ * Save all registers in pt_regs, and switch gs if needed.
* Use slow, but surefire "are we in kernel?" check.
* Return: ebx=0: need swapgs on exit, ebx=1: otherwise
*/
ENTRY(paranoid_entry)
UNWIND_HINT_FUNC
cld
+ PUSH_AND_CLEAR_REGS save_ret=1
+ ENCODE_FRAME_POINTER 8
movl $1, %ebx
movl $MSR_GS_BASE, %ecx
rdmsr
@@ -1168,12 +1166,14 @@ ENTRY(paranoid_exit)
END(paranoid_exit)
/*
- * Switch gs if needed.
+ * Save all registers in pt_regs, and switch GS if needed.
* Return: EBX=0: came from user mode; EBX=1: otherwise
*/
ENTRY(error_entry)
- UNWIND_HINT_REGS offset=8
+ UNWIND_HINT_FUNC
cld
+ PUSH_AND_CLEAR_REGS save_ret=1
+ ENCODE_FRAME_POINTER 8
testb $3, CS+8(%rsp)
jz .Lerror_kernelspace
@@ -1564,8 +1564,6 @@ end_repeat_nmi:
* frame to point back to repeat_nmi.
*/
pushq $-1 /* ORIG_RAX: no syscall to restart */
- PUSH_AND_CLEAR_REGS
- ENCODE_FRAME_POINTER
/*
* Use paranoid_entry to handle SWAPGS, but no need to use paranoid_exit
Patches currently in stable-queue which might be from linux(a)dominikbrodowski.net are
queue-4.14/x86-entry-reduce-the-code-footprint-of-the-idtentry-macro.patch
queue-4.14/x86-entry-64-use-xorl-for-faster-register-clearing.patch