This is a note to let you know that I've just added the patch titled
sysfs/cpu: Fix typos in vulnerability documentation
to the 4.4-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:
sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
and it can be found in the queue-4.4 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 9ecccfaa7cb5249bd31bdceb93fcf5bedb8a24d8 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Tue, 9 Jan 2018 15:02:51 +0000
Subject: sysfs/cpu: Fix typos in vulnerability documentation
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 9ecccfaa7cb5249bd31bdceb93fcf5bedb8a24d8 upstream.
Fixes: 87590ce6e ("sysfs/cpu: Add vulnerability folder")
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -276,7 +276,7 @@ What: /sys/devices/system/cpu/vulnerabi
/sys/devices/system/cpu/vulnerabilities/meltdown
/sys/devices/system/cpu/vulnerabilities/spectre_v1
/sys/devices/system/cpu/vulnerabilities/spectre_v2
-Date: Januar 2018
+Date: January 2018
Contact: Linux kernel mailing list <linux-kernel(a)vger.kernel.org>
Description: Information about CPU vulnerabilities
@@ -286,4 +286,4 @@ Description: Information about CPU vulne
"Not affected" CPU is not affected by the vulnerability
"Vulnerable" CPU is affected and no mitigation in effect
- "Mitigation: $M" CPU is affetcted and mitigation $M is in effect
+ "Mitigation: $M" CPU is affected and mitigation $M is in effect
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.4/x86-alternatives-add-missing-n-at-end-of-alternative-inline-asm.patch
queue-4.4/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.4/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.4/sysfs-cpu-add-vulnerability-folder.patch
queue-4.4/x86-alternatives-fix-optimize_nops-checking.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline/xen: Convert Xen hypercall indirect jumps
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-xen-convert-xen-hypercall-indirect-jumps.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 ea08816d5b185ab3d09e95e393f265af54560350 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Thu, 11 Jan 2018 21:46:31 +0000
Subject: x86/retpoline/xen: Convert Xen hypercall indirect jumps
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit ea08816d5b185ab3d09e95e393f265af54560350 upstream.
Convert indirect call in Xen hypercall to use non-speculative sequence,
when CONFIG_RETPOLINE is enabled.
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Arjan van de Ven <arjan(a)linux.intel.com>
Acked-by: Ingo Molnar <mingo(a)kernel.org>
Reviewed-by: Juergen Gross <jgross(a)suse.com>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-10-git-send-email-dwmw@amazon.co…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/xen/hypercall.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -44,6 +44,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/smap.h>
+#include <asm/nospec-branch.h>
#include <xen/interface/xen.h>
#include <xen/interface/sched.h>
@@ -217,9 +218,9 @@ privcmd_call(unsigned call,
__HYPERCALL_5ARG(a1, a2, a3, a4, a5);
stac();
- asm volatile("call *%[call]"
+ asm volatile(CALL_NOSPEC
: __HYPERCALL_5PARAM
- : [call] "a" (&hypercall_page[call])
+ : [thunk_target] "a" (&hypercall_page[call])
: __HYPERCALL_CLOBBER5);
clac();
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline: Remove compile time warning
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-remove-compile-time-warning.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 b8b9ce4b5aec8de9e23cabb0a26b78641f9ab1d6 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx(a)linutronix.de>
Date: Sun, 14 Jan 2018 22:13:29 +0100
Subject: x86/retpoline: Remove compile time warning
From: Thomas Gleixner <tglx(a)linutronix.de>
commit b8b9ce4b5aec8de9e23cabb0a26b78641f9ab1d6 upstream.
Remove the compile time warning when CONFIG_RETPOLINE=y and the compiler
does not have retpoline support. Linus rationale for this is:
It's wrong because it will just make people turn off RETPOLINE, and the
asm updates - and return stack clearing - that are independent of the
compiler are likely the most important parts because they are likely the
ones easiest to target.
And it's annoying because most people won't be able to do anything about
it. The number of people building their own compiler? Very small. So if
their distro hasn't got a compiler yet (and pretty much nobody does), the
warning is just annoying crap.
It is already properly reported as part of the sysfs interface. The
compile-time warning only encourages bad things.
Fixes: 76b043848fd2 ("x86/retpoline: Add initial retpoline support")
Requested-by: Linus Torvalds <torvalds(a)linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Cc: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Link: https://lkml.kernel.org/r/CA+55aFzWgquv4i6Mab6bASqYXg3ErV3XDFEYf=GEcCDQg5uA…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/Makefile | 2 --
1 file changed, 2 deletions(-)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -240,8 +240,6 @@ ifdef CONFIG_RETPOLINE
RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
ifneq ($(RETPOLINE_CFLAGS),)
KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
- else
- $(warning CONFIG_RETPOLINE=y, but not supported by the compiler. Toolchain update recommended.)
endif
endif
Patches currently in stable-queue which might be from tglx(a)linutronix.de are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/security-kconfig-correct-the-documentation-reference-for-pti.patch
queue-4.14/x86-pti-unbreak-efi-old_memmap.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-microcode-intel-extend-bdw-late-loading-with-a-revision-check.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/membarrier-disable-preemption-when-calling-smp_call_function_many.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/x86-documentation-add-pti-description.patch
queue-4.14/x86-acpi-handle-sci-interrupts-above-legacy-space-gracefully.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/selftests-x86-add-test_vsyscall.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-acpi-reduce-code-duplication-in-mp_override_legacy_irq.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-alternatives-fix-optimize_nops-checking.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
queue-4.14/kdump-write-correct-address-of-mem_section-into-vmcoreinfo.patch
queue-4.14/x86-perf-disable-intel_bts-when-pti.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
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-ftrace-convert-ftrace-assembler-indirect-jumps.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 9351803bd803cdbeb9b5a7850b7b6f464806e3db Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Thu, 11 Jan 2018 21:46:29 +0000
Subject: x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 9351803bd803cdbeb9b5a7850b7b6f464806e3db upstream.
Convert all indirect jumps in ftrace assembler code to use non-speculative
sequences when CONFIG_RETPOLINE is enabled.
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Arjan van de Ven <arjan(a)linux.intel.com>
Acked-by: Ingo Molnar <mingo(a)kernel.org>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-8-git-send-email-dwmw@amazon.co.…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/ftrace_32.S | 6 ++++--
arch/x86/kernel/ftrace_64.S | 8 ++++----
2 files changed, 8 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -8,6 +8,7 @@
#include <asm/segment.h>
#include <asm/export.h>
#include <asm/ftrace.h>
+#include <asm/nospec-branch.h>
#ifdef CC_USING_FENTRY
# define function_hook __fentry__
@@ -197,7 +198,8 @@ ftrace_stub:
movl 0x4(%ebp), %edx
subl $MCOUNT_INSN_SIZE, %eax
- call *ftrace_trace_function
+ movl ftrace_trace_function, %ecx
+ CALL_NOSPEC %ecx
popl %edx
popl %ecx
@@ -241,5 +243,5 @@ return_to_handler:
movl %eax, %ecx
popl %edx
popl %eax
- jmp *%ecx
+ JMP_NOSPEC %ecx
#endif
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -7,7 +7,7 @@
#include <asm/ptrace.h>
#include <asm/ftrace.h>
#include <asm/export.h>
-
+#include <asm/nospec-branch.h>
.code64
.section .entry.text, "ax"
@@ -286,8 +286,8 @@ trace:
* ip and parent ip are used and the list function is called when
* function tracing is enabled.
*/
- call *ftrace_trace_function
-
+ movq ftrace_trace_function, %r8
+ CALL_NOSPEC %r8
restore_mcount_regs
jmp fgraph_trace
@@ -329,5 +329,5 @@ GLOBAL(return_to_handler)
movq 8(%rsp), %rdx
movq (%rsp), %rax
addq $24, %rsp
- jmp *%rdi
+ JMP_NOSPEC %rdi
#endif
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline: Fill return stack buffer on vmexit
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-fill-return-stack-buffer-on-vmexit.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 117cc7a908c83697b0b737d15ae1eb5943afe35b Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Fri, 12 Jan 2018 11:11:27 +0000
Subject: x86/retpoline: Fill return stack buffer on vmexit
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 117cc7a908c83697b0b737d15ae1eb5943afe35b upstream.
In accordance with the Intel and AMD documentation, we need to overwrite
all entries in the RSB on exiting a guest, to prevent malicious branch
target predictions from affecting the host kernel. This is needed both
for retpoline and for IBRS.
[ak: numbers again for the RSB stuffing labels]
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Tested-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515755487-8524-1-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 78 ++++++++++++++++++++++++++++++++++-
arch/x86/kvm/svm.c | 4 +
arch/x86/kvm/vmx.c | 4 +
3 files changed, 85 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -7,6 +7,48 @@
#include <asm/alternative-asm.h>
#include <asm/cpufeatures.h>
+/*
+ * Fill the CPU return stack buffer.
+ *
+ * Each entry in the RSB, if used for a speculative 'ret', contains an
+ * infinite 'pause; jmp' loop to capture speculative execution.
+ *
+ * This is required in various cases for retpoline and IBRS-based
+ * mitigations for the Spectre variant 2 vulnerability. Sometimes to
+ * eliminate potentially bogus entries from the RSB, and sometimes
+ * purely to ensure that it doesn't get empty, which on some CPUs would
+ * allow predictions from other (unwanted!) sources to be used.
+ *
+ * We define a CPP macro such that it can be used from both .S files and
+ * inline assembly. It's possible to do a .macro and then include that
+ * from C via asm(".include <asm/nospec-branch.h>") but let's not go there.
+ */
+
+#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
+#define RSB_FILL_LOOPS 16 /* To avoid underflow */
+
+/*
+ * Google experimented with loop-unrolling and this turned out to be
+ * the optimal version — two calls, each with their own speculation
+ * trap should their return address end up getting used, in a loop.
+ */
+#define __FILL_RETURN_BUFFER(reg, nr, sp) \
+ mov $(nr/2), reg; \
+771: \
+ call 772f; \
+773: /* speculation trap */ \
+ pause; \
+ jmp 773b; \
+772: \
+ call 774f; \
+775: /* speculation trap */ \
+ pause; \
+ jmp 775b; \
+774: \
+ dec reg; \
+ jnz 771b; \
+ add $(BITS_PER_LONG/8) * nr, sp;
+
#ifdef __ASSEMBLY__
/*
@@ -76,6 +118,20 @@
#endif
.endm
+ /*
+ * A simpler FILL_RETURN_BUFFER macro. Don't make people use the CPP
+ * monstrosity above, manually.
+ */
+.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
+.Lskip_rsb_\@:
+#endif
+.endm
+
#else /* __ASSEMBLY__ */
#define ANNOTATE_NOSPEC_ALTERNATIVE \
@@ -119,7 +175,7 @@
X86_FEATURE_RETPOLINE)
# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
-#else /* No retpoline */
+#else /* No retpoline for C / inline asm */
# define CALL_NOSPEC "call *%[thunk_target]\n"
# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
#endif
@@ -134,5 +190,25 @@ enum spectre_v2_mitigation {
SPECTRE_V2_IBRS,
};
+/*
+ * On VMEXIT we must ensure that no RSB predictions learned in the guest
+ * can be followed in the host, by overwriting the RSB completely. Both
+ * retpoline and IBRS mitigations for Spectre v2 need this; only on future
+ * CPUs with IBRS_ATT *might* it be avoided.
+ */
+static inline void vmexit_fill_RSB(void)
+{
+#ifdef CONFIG_RETPOLINE
+ unsigned long loops = RSB_CLEAR_LOOPS / 2;
+
+ asm volatile (ANNOTATE_NOSPEC_ALTERNATIVE
+ ALTERNATIVE("jmp 910f",
+ __stringify(__FILL_RETURN_BUFFER(%0, RSB_CLEAR_LOOPS, %1)),
+ X86_FEATURE_RETPOLINE)
+ "910:"
+ : "=&r" (loops), ASM_CALL_CONSTRAINT
+ : "r" (loops) : "memory" );
+#endif
+}
#endif /* __ASSEMBLY__ */
#endif /* __NOSPEC_BRANCH_H__ */
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -45,6 +45,7 @@
#include <asm/debugreg.h>
#include <asm/kvm_para.h>
#include <asm/irq_remapping.h>
+#include <asm/nospec-branch.h>
#include <asm/virtext.h>
#include "trace.h"
@@ -5013,6 +5014,9 @@ static void svm_vcpu_run(struct kvm_vcpu
#endif
);
+ /* Eliminate branch target predictions from guest mode */
+ vmexit_fill_RSB();
+
#ifdef CONFIG_X86_64
wrmsrl(MSR_GS_BASE, svm->host.gs_base);
#else
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -50,6 +50,7 @@
#include <asm/apic.h>
#include <asm/irq_remapping.h>
#include <asm/mmu_context.h>
+#include <asm/nospec-branch.h>
#include "trace.h"
#include "pmu.h"
@@ -9483,6 +9484,9 @@ static void __noclone vmx_vcpu_run(struc
#endif
);
+ /* Eliminate branch target predictions from guest mode */
+ vmexit_fill_RSB();
+
/* MSR_IA32_DEBUGCTLMSR is zeroed on vmexit. Restore it if needed */
if (debugctlmsr)
update_debugctlmsr(debugctlmsr);
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline/entry: Convert entry assembler indirect jumps
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-entry-convert-entry-assembler-indirect-jumps.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 2641f08bb7fc63a636a2b18173221d7040a3512e Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Thu, 11 Jan 2018 21:46:28 +0000
Subject: x86/retpoline/entry: Convert entry assembler indirect jumps
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 2641f08bb7fc63a636a2b18173221d7040a3512e upstream.
Convert indirect jumps in core 32/64bit entry assembler code to use
non-speculative sequences when CONFIG_RETPOLINE is enabled.
Don't use CALL_NOSPEC in entry_SYSCALL_64_fastpath because the return
address after the 'call' instruction must be *precisely* at the
.Lentry_SYSCALL_64_after_fastpath label for stub_ptregs_64 to work,
and the use of alternatives will mess that up unless we play horrid
games to prepend with NOPs and make the variants the same length. It's
not worth it; in the case where we ALTERNATIVE out the retpoline, the
first instruction at __x86.indirect_thunk.rax is going to be a bare
jmp *%rax anyway.
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Ingo Molnar <mingo(a)kernel.org>
Acked-by: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-7-git-send-email-dwmw@amazon.co.…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/entry/entry_32.S | 5 +++--
arch/x86/entry/entry_64.S | 12 +++++++++---
2 files changed, 12 insertions(+), 5 deletions(-)
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -44,6 +44,7 @@
#include <asm/asm.h>
#include <asm/smap.h>
#include <asm/frame.h>
+#include <asm/nospec-branch.h>
.section .entry.text, "ax"
@@ -290,7 +291,7 @@ ENTRY(ret_from_fork)
/* kernel thread */
1: movl %edi, %eax
- call *%ebx
+ CALL_NOSPEC %ebx
/*
* A kernel thread is allowed to return here after successfully
* calling do_execve(). Exit to userspace to complete the execve()
@@ -919,7 +920,7 @@ common_exception:
movl %ecx, %es
TRACE_IRQS_OFF
movl %esp, %eax # pt_regs pointer
- call *%edi
+ CALL_NOSPEC %edi
jmp ret_from_exception
END(common_exception)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -37,6 +37,7 @@
#include <asm/pgtable_types.h>
#include <asm/export.h>
#include <asm/frame.h>
+#include <asm/nospec-branch.h>
#include <linux/err.h>
#include "calling.h"
@@ -187,7 +188,7 @@ ENTRY(entry_SYSCALL_64_trampoline)
*/
pushq %rdi
movq $entry_SYSCALL_64_stage2, %rdi
- jmp *%rdi
+ JMP_NOSPEC %rdi
END(entry_SYSCALL_64_trampoline)
.popsection
@@ -266,7 +267,12 @@ entry_SYSCALL_64_fastpath:
* It might end up jumping to the slow path. If it jumps, RAX
* and all argument registers are clobbered.
*/
+#ifdef CONFIG_RETPOLINE
+ movq sys_call_table(, %rax, 8), %rax
+ call __x86_indirect_thunk_rax
+#else
call *sys_call_table(, %rax, 8)
+#endif
.Lentry_SYSCALL_64_after_fastpath_call:
movq %rax, RAX(%rsp)
@@ -438,7 +444,7 @@ ENTRY(stub_ptregs_64)
jmp entry_SYSCALL64_slow_path
1:
- jmp *%rax /* Called from C */
+ JMP_NOSPEC %rax /* Called from C */
END(stub_ptregs_64)
.macro ptregs_stub func
@@ -517,7 +523,7 @@ ENTRY(ret_from_fork)
1:
/* kernel thread */
movq %r12, %rdi
- call *%rbx
+ CALL_NOSPEC %rbx
/*
* A kernel thread is allowed to return here after successfully
* calling do_execve(). Exit to userspace to complete the execve()
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline/checksum32: Convert assembler indirect jumps
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-checksum32-convert-assembler-indirect-jumps.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 5096732f6f695001fa2d6f1335a2680b37912c69 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Thu, 11 Jan 2018 21:46:32 +0000
Subject: x86/retpoline/checksum32: Convert assembler indirect jumps
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 5096732f6f695001fa2d6f1335a2680b37912c69 upstream.
Convert all indirect jumps in 32bit checksum assembler code to use
non-speculative sequences when CONFIG_RETPOLINE is enabled.
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Arjan van de Ven <arjan(a)linux.intel.com>
Acked-by: Ingo Molnar <mingo(a)kernel.org>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-11-git-send-email-dwmw@amazon.co…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/lib/checksum_32.S | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/arch/x86/lib/checksum_32.S
+++ b/arch/x86/lib/checksum_32.S
@@ -29,7 +29,8 @@
#include <asm/errno.h>
#include <asm/asm.h>
#include <asm/export.h>
-
+#include <asm/nospec-branch.h>
+
/*
* computes a partial checksum, e.g. for TCP/UDP fragments
*/
@@ -156,7 +157,7 @@ ENTRY(csum_partial)
negl %ebx
lea 45f(%ebx,%ebx,2), %ebx
testl %esi, %esi
- jmp *%ebx
+ JMP_NOSPEC %ebx
# Handle 2-byte-aligned regions
20: addw (%esi), %ax
@@ -439,7 +440,7 @@ ENTRY(csum_partial_copy_generic)
andl $-32,%edx
lea 3f(%ebx,%ebx), %ebx
testl %esi, %esi
- jmp *%ebx
+ JMP_NOSPEC %ebx
1: addl $64,%esi
addl $64,%edi
SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl)
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/pti: Fix !PCID and sanitize defines
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-pti-fix-pcid-and-sanitize-defines.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 f10ee3dcc9f0aba92a5c4c064628be5200765dc2 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx(a)linutronix.de>
Date: Sun, 14 Jan 2018 00:23:57 +0100
Subject: x86/pti: Fix !PCID and sanitize defines
From: Thomas Gleixner <tglx(a)linutronix.de>
commit f10ee3dcc9f0aba92a5c4c064628be5200765dc2 upstream.
The switch to the user space page tables in the low level ASM code sets
unconditionally bit 12 and bit 11 of CR3. Bit 12 is switching the base
address of the page directory to the user part, bit 11 is switching the
PCID to the PCID associated with the user page tables.
This fails on a machine which lacks PCID support because bit 11 is set in
CR3. Bit 11 is reserved when PCID is inactive.
While the Intel SDM claims that the reserved bits are ignored when PCID is
disabled, the AMD APM states that they should be cleared.
This went unnoticed as the AMD APM was not checked when the code was
developed and reviewed and test systems with Intel CPUs never failed to
boot. The report is against a Centos 6 host where the guest fails to boot,
so it's not yet clear whether this is a virt issue or can happen on real
hardware too, but thats irrelevant as the AMD APM clearly ask for clearing
the reserved bits.
Make sure that on non PCID machines bit 11 is not set by the page table
switching code.
Andy suggested to rename the related bits and masks so they are clearly
describing what they should be used for, which is done as well for clarity.
That split could have been done with alternatives but the macro hell is
horrible and ugly. This can be done on top if someone cares to remove the
extra orq. For now it's a straight forward fix.
Fixes: 6fd166aae78c ("x86/mm: Use/Fix PCID to optimize user/kernel switches")
Reported-by: Laura Abbott <labbott(a)redhat.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: stable <stable(a)vger.kernel.org>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Willy Tarreau <w(a)1wt.eu>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801140009150.2371@nanos
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/entry/calling.h | 36 +++++++++++++++++----------------
arch/x86/include/asm/processor-flags.h | 2 -
arch/x86/include/asm/tlbflush.h | 6 ++---
3 files changed, 23 insertions(+), 21 deletions(-)
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -198,8 +198,11 @@ For 32-bit we have the following convent
* PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two
* halves:
*/
-#define PTI_SWITCH_PGTABLES_MASK (1<<PAGE_SHIFT)
-#define PTI_SWITCH_MASK (PTI_SWITCH_PGTABLES_MASK|(1<<X86_CR3_PTI_SWITCH_BIT))
+#define PTI_USER_PGTABLE_BIT PAGE_SHIFT
+#define PTI_USER_PGTABLE_MASK (1 << PTI_USER_PGTABLE_BIT)
+#define PTI_USER_PCID_BIT X86_CR3_PTI_PCID_USER_BIT
+#define PTI_USER_PCID_MASK (1 << PTI_USER_PCID_BIT)
+#define PTI_USER_PGTABLE_AND_PCID_MASK (PTI_USER_PCID_MASK | PTI_USER_PGTABLE_MASK)
.macro SET_NOFLUSH_BIT reg:req
bts $X86_CR3_PCID_NOFLUSH_BIT, \reg
@@ -208,7 +211,7 @@ For 32-bit we have the following convent
.macro ADJUST_KERNEL_CR3 reg:req
ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID
/* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */
- andq $(~PTI_SWITCH_MASK), \reg
+ andq $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg
.endm
.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
@@ -239,15 +242,19 @@ For 32-bit we have the following convent
/* Flush needed, clear the bit */
btr \scratch_reg, THIS_CPU_user_pcid_flush_mask
movq \scratch_reg2, \scratch_reg
- jmp .Lwrcr3_\@
+ jmp .Lwrcr3_pcid_\@
.Lnoflush_\@:
movq \scratch_reg2, \scratch_reg
SET_NOFLUSH_BIT \scratch_reg
+.Lwrcr3_pcid_\@:
+ /* Flip the ASID to the user version */
+ orq $(PTI_USER_PCID_MASK), \scratch_reg
+
.Lwrcr3_\@:
- /* Flip the PGD and ASID to the user version */
- orq $(PTI_SWITCH_MASK), \scratch_reg
+ /* Flip the PGD to the user version */
+ orq $(PTI_USER_PGTABLE_MASK), \scratch_reg
mov \scratch_reg, %cr3
.Lend_\@:
.endm
@@ -263,17 +270,12 @@ For 32-bit we have the following convent
movq %cr3, \scratch_reg
movq \scratch_reg, \save_reg
/*
- * Is the "switch mask" all zero? That means that both of
- * these are zero:
- *
- * 1. The user/kernel PCID bit, and
- * 2. The user/kernel "bit" that points CR3 to the
- * bottom half of the 8k PGD
- *
- * That indicates a kernel CR3 value, not a user CR3.
+ * Test the user pagetable bit. If set, then the user page tables
+ * are active. If clear CR3 already has the kernel page table
+ * active.
*/
- testq $(PTI_SWITCH_MASK), \scratch_reg
- jz .Ldone_\@
+ bt $PTI_USER_PGTABLE_BIT, \scratch_reg
+ jnc .Ldone_\@
ADJUST_KERNEL_CR3 \scratch_reg
movq \scratch_reg, %cr3
@@ -290,7 +292,7 @@ For 32-bit we have the following convent
* KERNEL pages can always resume with NOFLUSH as we do
* explicit flushes.
*/
- bt $X86_CR3_PTI_SWITCH_BIT, \save_reg
+ bt $PTI_USER_PGTABLE_BIT, \save_reg
jnc .Lnoflush_\@
/*
--- a/arch/x86/include/asm/processor-flags.h
+++ b/arch/x86/include/asm/processor-flags.h
@@ -40,7 +40,7 @@
#define CR3_NOFLUSH BIT_ULL(63)
#ifdef CONFIG_PAGE_TABLE_ISOLATION
-# define X86_CR3_PTI_SWITCH_BIT 11
+# define X86_CR3_PTI_PCID_USER_BIT 11
#endif
#else
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -81,13 +81,13 @@ static inline u16 kern_pcid(u16 asid)
* Make sure that the dynamic ASID space does not confict with the
* bit we are using to switch between user and kernel ASIDs.
*/
- BUILD_BUG_ON(TLB_NR_DYN_ASIDS >= (1 << X86_CR3_PTI_SWITCH_BIT));
+ BUILD_BUG_ON(TLB_NR_DYN_ASIDS >= (1 << X86_CR3_PTI_PCID_USER_BIT));
/*
* The ASID being passed in here should have respected the
* MAX_ASID_AVAILABLE and thus never have the switch bit set.
*/
- VM_WARN_ON_ONCE(asid & (1 << X86_CR3_PTI_SWITCH_BIT));
+ VM_WARN_ON_ONCE(asid & (1 << X86_CR3_PTI_PCID_USER_BIT));
#endif
/*
* The dynamically-assigned ASIDs that get passed in are small
@@ -112,7 +112,7 @@ static inline u16 user_pcid(u16 asid)
{
u16 ret = kern_pcid(asid);
#ifdef CONFIG_PAGE_TABLE_ISOLATION
- ret |= 1 << X86_CR3_PTI_SWITCH_BIT;
+ ret |= 1 << X86_CR3_PTI_PCID_USER_BIT;
#endif
return ret;
}
Patches currently in stable-queue which might be from tglx(a)linutronix.de are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/security-kconfig-correct-the-documentation-reference-for-pti.patch
queue-4.14/x86-pti-unbreak-efi-old_memmap.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-microcode-intel-extend-bdw-late-loading-with-a-revision-check.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/membarrier-disable-preemption-when-calling-smp_call_function_many.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/x86-documentation-add-pti-description.patch
queue-4.14/x86-acpi-handle-sci-interrupts-above-legacy-space-gracefully.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/selftests-x86-add-test_vsyscall.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-acpi-reduce-code-duplication-in-mp_override_legacy_irq.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-alternatives-fix-optimize_nops-checking.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
queue-4.14/kdump-write-correct-address-of-mem_section-into-vmcoreinfo.patch
queue-4.14/x86-perf-disable-intel_bts-when-pti.patch
This is a note to let you know that I've just added the patch titled
x86,perf: Disable intel_bts when PTI
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-perf-disable-intel_bts-when-pti.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 99a9dc98ba52267ce5e062b52de88ea1f1b2a7d8 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz(a)infradead.org>
Date: Sun, 14 Jan 2018 11:27:13 +0100
Subject: x86,perf: Disable intel_bts when PTI
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Peter Zijlstra <peterz(a)infradead.org>
commit 99a9dc98ba52267ce5e062b52de88ea1f1b2a7d8 upstream.
The intel_bts driver does not use the 'normal' BTS buffer which is exposed
through the cpu_entry_area but instead uses the memory allocated for the
perf AUX buffer.
This obviously comes apart when using PTI because then the kernel mapping;
which includes that AUX buffer memory; disappears. Fixing this requires to
expose a mapping which is visible in all context and that's not trivial.
As a quick fix disable this driver when PTI is enabled to prevent
malfunction.
Fixes: 385ce0ea4c07 ("x86/mm/pti: Add Kconfig")
Reported-by: Vince Weaver <vincent.weaver(a)maine.edu>
Reported-by: Robert Święcki <robert(a)swiecki.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com>
Cc: greg(a)kroah.com
Cc: hughd(a)google.com
Cc: luto(a)amacapital.net
Cc: Vince Weaver <vince(a)deater.net>
Cc: torvalds(a)linux-foundation.org
Cc: stable(a)vger.kernel.org
Link: https://lkml.kernel.org/r/20180114102713.GB6166@worktop.programming.kicks-a…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/events/intel/bts.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
--- a/arch/x86/events/intel/bts.c
+++ b/arch/x86/events/intel/bts.c
@@ -582,6 +582,24 @@ static __init int bts_init(void)
if (!boot_cpu_has(X86_FEATURE_DTES64) || !x86_pmu.bts)
return -ENODEV;
+ if (boot_cpu_has(X86_FEATURE_PTI)) {
+ /*
+ * BTS hardware writes through a virtual memory map we must
+ * either use the kernel physical map, or the user mapping of
+ * the AUX buffer.
+ *
+ * However, since this driver supports per-CPU and per-task inherit
+ * we cannot use the user mapping since it will not be availble
+ * if we're not running the owning process.
+ *
+ * With PTI we can't use the kernal map either, because its not
+ * there when we run userspace.
+ *
+ * For now, disable this driver when using PTI.
+ */
+ return -ENODEV;
+ }
+
bts_pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_ITRACE |
PERF_PMU_CAP_EXCLUSIVE;
bts_pmu.task_ctx_nr = perf_sw_context;
Patches currently in stable-queue which might be from peterz(a)infradead.org are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-pti-unbreak-efi-old_memmap.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.14/membarrier-disable-preemption-when-calling-smp_call_function_many.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.14/x86-pti-fix-pcid-and-sanitize-defines.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.14/selftests-x86-add-test_vsyscall.patch
queue-4.14/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.14/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.14/x86-retpoline-remove-compile-time-warning.patch
queue-4.14/x86-alternatives-fix-optimize_nops-checking.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
queue-4.14/x86-perf-disable-intel_bts-when-pti.patch
This is a note to let you know that I've just added the patch titled
security/Kconfig: Correct the Documentation reference for PTI
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:
security-kconfig-correct-the-documentation-reference-for-pti.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 a237f762681e2a394ca67f21df2feb2b76a3609b Mon Sep 17 00:00:00 2001
From: "W. Trevor King" <wking(a)tremily.us>
Date: Fri, 12 Jan 2018 15:24:59 -0800
Subject: security/Kconfig: Correct the Documentation reference for PTI
From: W. Trevor King <wking(a)tremily.us>
commit a237f762681e2a394ca67f21df2feb2b76a3609b upstream.
When the config option for PTI was added a reference to documentation was
added as well. But the documentation did not exist at that point. The final
documentation has a different file name.
Fix it up to point to the proper file.
Fixes: 385ce0ea ("x86/mm/pti: Add Kconfig")
Signed-off-by: W. Trevor King <wking(a)tremily.us>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: linux-mm(a)kvack.org
Cc: linux-security-module(a)vger.kernel.org
Cc: James Morris <james.l.morris(a)oracle.com>
Cc: "Serge E. Hallyn" <serge(a)hallyn.com>
Cc: stable(a)vger.kernel.org
Link: https://lkml.kernel.org/r/3009cc8ccbddcd897ec1e0cb6dda524929de0d14.15157993…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
security/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -63,7 +63,7 @@ config PAGE_TABLE_ISOLATION
ensuring that the majority of kernel addresses are not mapped
into userspace.
- See Documentation/x86/pagetable-isolation.txt for more details.
+ See Documentation/x86/pti.txt for more details.
config SECURITY_INFINIBAND
bool "Infiniband Security Hooks"
Patches currently in stable-queue which might be from wking(a)tremily.us are
queue-4.14/security-kconfig-correct-the-documentation-reference-for-pti.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline: Add initial retpoline support
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-add-initial-retpoline-support.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 76b043848fd22dbf7f8bf3a1452f8c70d557b860 Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw(a)amazon.co.uk>
Date: Thu, 11 Jan 2018 21:46:25 +0000
Subject: x86/retpoline: Add initial retpoline support
From: David Woodhouse <dwmw(a)amazon.co.uk>
commit 76b043848fd22dbf7f8bf3a1452f8c70d557b860 upstream.
Enable the use of -mindirect-branch=thunk-extern in newer GCC, and provide
the corresponding thunks. Provide assembler macros for invoking the thunks
in the same way that GCC does, from native and inline assembler.
This adds X86_FEATURE_RETPOLINE and sets it by default on all CPUs. In
some circumstances, IBRS microcode features may be used instead, and the
retpoline can be disabled.
On AMD CPUs if lfence is serialising, the retpoline can be dramatically
simplified to a simple "lfence; jmp *\reg". A future patch, after it has
been verified that lfence really is serialising in all circumstances, can
enable this by setting the X86_FEATURE_RETPOLINE_AMD feature bit in addition
to X86_FEATURE_RETPOLINE.
Do not align the retpoline in the altinstr section, because there is no
guarantee that it stays aligned when it's copied over the oldinstr during
alternative patching.
[ Andi Kleen: Rename the macros, add CONFIG_RETPOLINE option, export thunks]
[ tglx: Put actual function CALL/JMP in front of the macros, convert to
symbolic labels ]
[ dwmw2: Convert back to numeric labels, merge objtool fixes ]
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Acked-by: Arjan van de Ven <arjan(a)linux.intel.com>
Acked-by: Ingo Molnar <mingo(a)kernel.org>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-4-git-send-email-dwmw@amazon.co.…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/Kconfig | 13 +++
arch/x86/Makefile | 10 ++
arch/x86/include/asm/asm-prototypes.h | 25 ++++++
arch/x86/include/asm/cpufeatures.h | 2
arch/x86/include/asm/nospec-branch.h | 128 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/common.c | 4 +
arch/x86/lib/Makefile | 1
arch/x86/lib/retpoline.S | 48 ++++++++++++
8 files changed, 231 insertions(+)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -429,6 +429,19 @@ config GOLDFISH
def_bool y
depends on X86_GOLDFISH
+config RETPOLINE
+ bool "Avoid speculative indirect branches in kernel"
+ default y
+ help
+ Compile kernel with the retpoline compiler options to guard against
+ kernel-to-user data leaks by avoiding speculative indirect
+ branches. Requires a compiler with -mindirect-branch=thunk-extern
+ support for full protection. The kernel may run slower.
+
+ Without compiler support, at least indirect branches in assembler
+ code are eliminated. Since this includes the syscall entry path,
+ it is not entirely pointless.
+
config INTEL_RDT
bool "Intel Resource Director Technology support"
default n
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -235,6 +235,16 @@ KBUILD_CFLAGS += -Wno-sign-compare
#
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
+# Avoid indirect branches in kernel to deal with Spectre
+ifdef CONFIG_RETPOLINE
+ RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
+ ifneq ($(RETPOLINE_CFLAGS),)
+ KBUILD_CFLAGS += $(RETPOLINE_CFLAGS) -DRETPOLINE
+ else
+ $(warning CONFIG_RETPOLINE=y, but not supported by the compiler. Toolchain update recommended.)
+ endif
+endif
+
archscripts: scripts_basic
$(Q)$(MAKE) $(build)=arch/x86/tools relocs
--- a/arch/x86/include/asm/asm-prototypes.h
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -11,7 +11,32 @@
#include <asm/pgtable.h>
#include <asm/special_insns.h>
#include <asm/preempt.h>
+#include <asm/asm.h>
#ifndef CONFIG_X86_CMPXCHG64
extern void cmpxchg8b_emu(void);
#endif
+
+#ifdef CONFIG_RETPOLINE
+#ifdef CONFIG_X86_32
+#define INDIRECT_THUNK(reg) extern asmlinkage void __x86_indirect_thunk_e ## reg(void);
+#else
+#define INDIRECT_THUNK(reg) extern asmlinkage void __x86_indirect_thunk_r ## reg(void);
+INDIRECT_THUNK(8)
+INDIRECT_THUNK(9)
+INDIRECT_THUNK(10)
+INDIRECT_THUNK(11)
+INDIRECT_THUNK(12)
+INDIRECT_THUNK(13)
+INDIRECT_THUNK(14)
+INDIRECT_THUNK(15)
+#endif
+INDIRECT_THUNK(ax)
+INDIRECT_THUNK(bx)
+INDIRECT_THUNK(cx)
+INDIRECT_THUNK(dx)
+INDIRECT_THUNK(si)
+INDIRECT_THUNK(di)
+INDIRECT_THUNK(bp)
+INDIRECT_THUNK(sp)
+#endif /* CONFIG_RETPOLINE */
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -203,6 +203,8 @@
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_SME ( 7*32+10) /* AMD Secure Memory Encryption */
#define X86_FEATURE_PTI ( 7*32+11) /* Kernel Page Table Isolation enabled */
+#define X86_FEATURE_RETPOLINE ( 7*32+12) /* Generic Retpoline mitigation for Spectre variant 2 */
+#define X86_FEATURE_RETPOLINE_AMD ( 7*32+13) /* AMD Retpoline mitigation for Spectre variant 2 */
#define X86_FEATURE_INTEL_PPIN ( 7*32+14) /* Intel Processor Inventory Number */
#define X86_FEATURE_INTEL_PT ( 7*32+15) /* Intel Processor Trace */
#define X86_FEATURE_AVX512_4VNNIW ( 7*32+16) /* AVX-512 Neural Network Instructions */
--- /dev/null
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __NOSPEC_BRANCH_H__
+#define __NOSPEC_BRANCH_H__
+
+#include <asm/alternative.h>
+#include <asm/alternative-asm.h>
+#include <asm/cpufeatures.h>
+
+#ifdef __ASSEMBLY__
+
+/*
+ * This should be used immediately before a retpoline alternative. It tells
+ * objtool where the retpolines are so that it can make sense of the control
+ * flow by just reading the original instruction(s) and ignoring the
+ * alternatives.
+ */
+.macro ANNOTATE_NOSPEC_ALTERNATIVE
+ .Lannotate_\@:
+ .pushsection .discard.nospec
+ .long .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.
+ */
+.macro RETPOLINE_JMP reg:req
+ call .Ldo_rop_\@
+.Lspec_trap_\@:
+ pause
+ jmp .Lspec_trap_\@
+.Ldo_rop_\@:
+ mov \reg, (%_ASM_SP)
+ ret
+.endm
+
+/*
+ * This is a wrapper around RETPOLINE_JMP so the called function in reg
+ * returns to the instruction after the macro.
+ */
+.macro RETPOLINE_CALL reg:req
+ jmp .Ldo_call_\@
+.Ldo_retpoline_jmp_\@:
+ RETPOLINE_JMP \reg
+.Ldo_call_\@:
+ call .Ldo_retpoline_jmp_\@
+.endm
+
+/*
+ * JMP_NOSPEC and CALL_NOSPEC macros can be used instead of a simple
+ * indirect jmp/call which may be susceptible to the Spectre variant 2
+ * attack.
+ */
+.macro JMP_NOSPEC reg:req
+#ifdef CONFIG_RETPOLINE
+ ANNOTATE_NOSPEC_ALTERNATIVE
+ ALTERNATIVE_2 __stringify(jmp *\reg), \
+ __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \
+ __stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD
+#else
+ jmp *\reg
+#endif
+.endm
+
+.macro CALL_NOSPEC reg:req
+#ifdef CONFIG_RETPOLINE
+ ANNOTATE_NOSPEC_ALTERNATIVE
+ ALTERNATIVE_2 __stringify(call *\reg), \
+ __stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\
+ __stringify(lfence; call *\reg), X86_FEATURE_RETPOLINE_AMD
+#else
+ call *\reg
+#endif
+.endm
+
+#else /* __ASSEMBLY__ */
+
+#define ANNOTATE_NOSPEC_ALTERNATIVE \
+ "999:\n\t" \
+ ".pushsection .discard.nospec\n\t" \
+ ".long 999b - .\n\t" \
+ ".popsection\n\t"
+
+#if defined(CONFIG_X86_64) && defined(RETPOLINE)
+
+/*
+ * Since the inline asm uses the %V modifier which is only in newer GCC,
+ * the 64-bit one is dependent on RETPOLINE not CONFIG_RETPOLINE.
+ */
+# define CALL_NOSPEC \
+ ANNOTATE_NOSPEC_ALTERNATIVE \
+ ALTERNATIVE( \
+ "call *%[thunk_target]\n", \
+ "call __x86_indirect_thunk_%V[thunk_target]\n", \
+ X86_FEATURE_RETPOLINE)
+# define THUNK_TARGET(addr) [thunk_target] "r" (addr)
+
+#elif defined(CONFIG_X86_32) && defined(CONFIG_RETPOLINE)
+/*
+ * For i386 we use the original ret-equivalent retpoline, because
+ * otherwise we'll run out of registers. We don't care about CET
+ * here, anyway.
+ */
+# define CALL_NOSPEC ALTERNATIVE("call *%[thunk_target]\n", \
+ " jmp 904f;\n" \
+ " .align 16\n" \
+ "901: call 903f;\n" \
+ "902: pause;\n" \
+ " jmp 902b;\n" \
+ " .align 16\n" \
+ "903: addl $4, %%esp;\n" \
+ " pushl %[thunk_target];\n" \
+ " ret;\n" \
+ " .align 16\n" \
+ "904: call 901b;\n", \
+ X86_FEATURE_RETPOLINE)
+
+# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
+#else /* No retpoline */
+# define CALL_NOSPEC "call *%[thunk_target]\n"
+# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* __NOSPEC_BRANCH_H__ */
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -905,6 +905,10 @@ static void __init early_identify_cpu(st
setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+#ifdef CONFIG_RETPOLINE
+ setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
+#endif
+
fpu__init_system(c);
#ifdef CONFIG_X86_32
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -26,6 +26,7 @@ lib-y += memcpy_$(BITS).o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
+lib-$(CONFIG_RETPOLINE) += retpoline.o
obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
--- /dev/null
+++ b/arch/x86/lib/retpoline.S
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/stringify.h>
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+#include <asm/cpufeatures.h>
+#include <asm/alternative-asm.h>
+#include <asm/export.h>
+#include <asm/nospec-branch.h>
+
+.macro THUNK reg
+ .section .text.__x86.indirect_thunk.\reg
+
+ENTRY(__x86_indirect_thunk_\reg)
+ CFI_STARTPROC
+ JMP_NOSPEC %\reg
+ CFI_ENDPROC
+ENDPROC(__x86_indirect_thunk_\reg)
+.endm
+
+/*
+ * Despite being an assembler file we can't just use .irp here
+ * because __KSYM_DEPS__ only uses the C preprocessor and would
+ * only see one instance of "__x86_indirect_thunk_\reg" rather
+ * than one per register with the correct names. So we do it
+ * the simple and nasty way...
+ */
+#define EXPORT_THUNK(reg) EXPORT_SYMBOL(__x86_indirect_thunk_ ## reg)
+#define GENERATE_THUNK(reg) THUNK reg ; EXPORT_THUNK(reg)
+
+GENERATE_THUNK(_ASM_AX)
+GENERATE_THUNK(_ASM_BX)
+GENERATE_THUNK(_ASM_CX)
+GENERATE_THUNK(_ASM_DX)
+GENERATE_THUNK(_ASM_SI)
+GENERATE_THUNK(_ASM_DI)
+GENERATE_THUNK(_ASM_BP)
+GENERATE_THUNK(_ASM_SP)
+#ifdef CONFIG_64BIT
+GENERATE_THUNK(r8)
+GENERATE_THUNK(r9)
+GENERATE_THUNK(r10)
+GENERATE_THUNK(r11)
+GENERATE_THUNK(r12)
+GENERATE_THUNK(r13)
+GENERATE_THUNK(r14)
+GENERATE_THUNK(r15)
+#endif
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/x86-cpufeatures-add-x86_bug_spectre_v.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/sysfs-cpu-fix-typos-in-vulnerability-documentation.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-cpu-implement-cpu-vulnerabilites-sysfs-functions.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
queue-4.14/sysfs-cpu-add-vulnerability-folder.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/pti: Make unpoison of pgd for trusted boot work for real
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-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.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 445b69e3b75e42362a5bdc13c8b8f61599e2228a Mon Sep 17 00:00:00 2001
From: Dave Hansen <dave.hansen(a)linux.intel.com>
Date: Wed, 10 Jan 2018 14:49:39 -0800
Subject: x86/pti: Make unpoison of pgd for trusted boot work for real
From: Dave Hansen <dave.hansen(a)linux.intel.com>
commit 445b69e3b75e42362a5bdc13c8b8f61599e2228a upstream.
The inital fix for trusted boot and PTI potentially misses the pgd clearing
if pud_alloc() sets a PGD. It probably works in *practice* because for two
adjacent calls to map_tboot_page() that share a PGD entry, the first will
clear NX, *then* allocate and set the PGD (without NX clear). The second
call will *not* allocate but will clear the NX bit.
Defer the NX clearing to a point after it is known that all top-level
allocations have occurred. Add a comment to clarify why.
[ tglx: Massaged changelog ]
Fixes: 262b6b30087 ("x86/tboot: Unbreak tboot with PTI enabled")
Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Reviewed-by: Andrea Arcangeli <aarcange(a)redhat.com>
Cc: Jon Masters <jcm(a)redhat.com>
Cc: "Tim Chen" <tim.c.chen(a)linux.intel.com>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: peterz(a)infradead.org
Cc: ning.sun(a)intel.com
Cc: tboot-devel(a)lists.sourceforge.net
Cc: andi(a)firstfloor.org
Cc: luto(a)kernel.org
Cc: law(a)redhat.com
Cc: pbonzini(a)redhat.com
Cc: torvalds(a)linux-foundation.org
Cc: gregkh(a)linux-foundation.org
Cc: dwmw(a)amazon.co.uk
Cc: nickc(a)redhat.com
Cc: stable(a)vger.kernel.org
Link: https://lkml.kernel.org/r/20180110224939.2695CD47@viggo.jf.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/tboot.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -127,7 +127,6 @@ static int map_tboot_page(unsigned long
p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
if (!p4d)
return -1;
- pgd->pgd &= ~_PAGE_NX;
pud = pud_alloc(&tboot_mm, p4d, vaddr);
if (!pud)
return -1;
@@ -139,6 +138,17 @@ static int map_tboot_page(unsigned long
return -1;
set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
pte_unmap(pte);
+
+ /*
+ * PTI poisons low addresses in the kernel page tables in the
+ * name of making them unusable for userspace. To execute
+ * code at such a low address, the poison must be cleared.
+ *
+ * Note: 'pgd' actually gets set in p4d_alloc() _or_
+ * pud_alloc() depending on 4/5-level paging.
+ */
+ pgd->pgd &= ~_PAGE_NX;
+
return 0;
}
Patches currently in stable-queue which might be from dave.hansen(a)linux.intel.com are
queue-4.14/x86-pti-unbreak-efi-old_memmap.patch
queue-4.14/x86-documentation-add-pti-description.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
queue-4.14/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch
From: Vincent Wang <vincent.wang(a)spreadtrum.com>
list_del_rcu() should be used to replace list_del() in the function
_remove_list_dev(), since the opp is a rcu protected pointer.
For example, on an ARM big.Little platform of spreadtrum, there are
little cluster, big cluster and gpu using pm_opp. And the opp_table
of big cluster will be removed when big cluster is removed, which
is implemented in the cpufreq driver. Sometimes an issue maybe occur:
[ 237.647758] c0 Unable to handle kernel paging request at virtual address dead000000000110
[ 237.647776] c0 pgd = ffffffc073e78000
[ 237.647786] c0 [dead000000000110] *pgd=0000000000000000, *pud=0000000000000000
[ 237.647808] c0 Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 237.653535] c0 Modules linked in: sprdwl_ng(O) mtty marlin2_fm mali_kbase(O)
[ 237.653569] c0 CPU: 0 PID: 38 Comm: kworker/u12:1 Tainted: G S W O 4.4.83+ #1
[ 237.653578] c0 Hardware name: Spreadtrum SP9850KHsmt 1h10 Board (DT)
[ 237.653594] c0 Workqueue: devfreq_wq devfreq_monitor
[ 237.653605] c0 task: ffffffc0babd0d80 task.stack: ffffffc0badbc000
[ 237.653619] c0 PC is at _find_device_opp+0x58/0xac
[ 237.653629] c0 LR is at dev_pm_opp_find_freq_ceil+0x2c/0xb8
[ 237.921294] c0 Call trace:
[ 237.921425] c0 [<ffffff80085362b0>] _find_device_opp+0x58/0xac
[ 237.921437] c0 [<ffffff8008536560>] dev_pm_opp_find_freq_ceil+0x2c/0xb8
[ 237.921452] c0 [<ffffff80088760f4>] devfreq_recommended_opp+0x54/0x7c
[ 237.921494] c0 [<ffffff8000b6a96c>] kbase_wait_write_flush+0x164/0x358 [mali_kbase]
[ 237.921504] c0 [<ffffff800887485c>] update_devfreq+0x8c/0xf8
[ 237.921514] c0 [<ffffff80088749e4>] devfreq_monitor+0x34/0x94
[ 237.921529] c0 [<ffffff80080bd75c>] process_one_work+0x154/0x458
[ 237.921539] c0 [<ffffff80080be428>] worker_thread+0x134/0x4a4
[ 237.921551] c0 [<ffffff80080c4bec>] kthread+0xdc/0xf0
[ 237.921564] c0 [<ffffff8008085f20>] ret_from_fork+0x10/0x30
Cc: stable <stable(a)vger.kernel.org> # 4.4
Signed-off-by: Vincent Wang <vincent.wang(a)spreadtrum.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang(a)spreadtrum.com>
Acked-by: Viresh Kumar <viresh.kumar(a)linaro.org>
---
This patch is for 4.4 stable branch only.
Once this patch accepted, I can cook a similar patch for 4.9 stable branch.
This fix can't be done to upstream kernel as the OPP code doesn't
use RCUs anymore.
---
drivers/base/power/opp/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index db6e7e5..e0eac53 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -463,7 +463,7 @@ static void _kfree_list_dev_rcu(struct rcu_head *head)
static void _remove_list_dev(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
{
- list_del(&list_dev->node);
+ list_del_rcu(&list_dev->node);
call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
_kfree_list_dev_rcu);
}
--
1.9.1
This is a note to let you know that I've just added the patch titled
objtool: Detect jumps to retpoline thunks
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:
objtool-detect-jumps-to-retpoline-thunks.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 39b735332cb8b33a27c28592d969e4016c86c3ea Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe(a)redhat.com>
Date: Thu, 11 Jan 2018 21:46:23 +0000
Subject: objtool: Detect jumps to retpoline thunks
From: Josh Poimboeuf <jpoimboe(a)redhat.com>
commit 39b735332cb8b33a27c28592d969e4016c86c3ea upstream.
A direct jump to a retpoline thunk is really an indirect jump in
disguise. Change the objtool instruction type accordingly.
Objtool needs to know where indirect branches are so it can detect
switch statement jump tables.
This fixes a bunch of warnings with CONFIG_RETPOLINE like:
arch/x86/events/intel/uncore_nhmex.o: warning: objtool: nhmex_rbox_msr_enable_event()+0x44: sibling call from callable instruction with modified stack frame
kernel/signal.o: warning: objtool: copy_siginfo_to_user()+0x91: sibling call from callable instruction with modified stack frame
...
Signed-off-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-2-git-send-email-dwmw@amazon.co.…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
tools/objtool/check.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -456,6 +456,13 @@ static int add_jump_destinations(struct
} else if (rela->sym->sec->idx) {
dest_sec = rela->sym->sec;
dest_off = rela->sym->sym.st_value + rela->addend + 4;
+ } else if (strstr(rela->sym->name, "_indirect_thunk_")) {
+ /*
+ * Retpoline jumps are really dynamic jumps in
+ * disguise, so convert them accordingly.
+ */
+ insn->type = INSN_JUMP_DYNAMIC;
+ continue;
} else {
/* sibling call */
insn->jump_dest = 0;
Patches currently in stable-queue which might be from jpoimboe(a)redhat.com are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
objtool: Allow alternatives to be ignored
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:
objtool-allow-alternatives-to-be-ignored.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 258c76059cece01bebae098e81bacb1af2edad17 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe(a)redhat.com>
Date: Thu, 11 Jan 2018 21:46:24 +0000
Subject: objtool: Allow alternatives to be ignored
From: Josh Poimboeuf <jpoimboe(a)redhat.com>
commit 258c76059cece01bebae098e81bacb1af2edad17 upstream.
Getting objtool to understand retpolines is going to be a bit of a
challenge. For now, take advantage of the fact that retpolines are
patched in with alternatives. Just read the original (sane)
non-alternative instruction, and ignore the patched-in retpoline.
This allows objtool to understand the control flow *around* the
retpoline, even if it can't yet follow what's inside. This means the
ORC unwinder will fail to unwind from inside a retpoline, but will work
fine otherwise.
Signed-off-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: gnomes(a)lxorguk.ukuu.org.uk
Cc: Rik van Riel <riel(a)redhat.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: thomas.lendacky(a)amd.com
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jiri Kosina <jikos(a)kernel.org>
Cc: Andy Lutomirski <luto(a)amacapital.net>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Kees Cook <keescook(a)google.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/1515707194-20531-3-git-send-email-dwmw@amazon.co.…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
tools/objtool/check.c | 62 +++++++++++++++++++++++++++++++++++++++++++++-----
tools/objtool/check.h | 2 -
2 files changed, 57 insertions(+), 7 deletions(-)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -428,6 +428,40 @@ static void add_ignores(struct objtool_f
}
/*
+ * FIXME: For now, just ignore any alternatives which add retpolines. This is
+ * a temporary hack, as it doesn't allow ORC to unwind from inside a retpoline.
+ * But it at least allows objtool to understand the control flow *around* the
+ * retpoline.
+ */
+static int add_nospec_ignores(struct objtool_file *file)
+{
+ struct section *sec;
+ struct rela *rela;
+ struct instruction *insn;
+
+ sec = find_section_by_name(file->elf, ".rela.discard.nospec");
+ if (!sec)
+ return 0;
+
+ list_for_each_entry(rela, &sec->rela_list, list) {
+ if (rela->sym->type != STT_SECTION) {
+ WARN("unexpected relocation symbol type in %s", sec->name);
+ return -1;
+ }
+
+ insn = find_insn(file, rela->sym->sec, rela->addend);
+ if (!insn) {
+ WARN("bad .discard.nospec entry");
+ return -1;
+ }
+
+ insn->ignore_alts = true;
+ }
+
+ return 0;
+}
+
+/*
* Find the destination instructions for all jumps.
*/
static int add_jump_destinations(struct objtool_file *file)
@@ -509,11 +543,18 @@ static int add_call_destinations(struct
dest_off = insn->offset + insn->len + insn->immediate;
insn->call_dest = find_symbol_by_offset(insn->sec,
dest_off);
+ /*
+ * FIXME: Thanks to retpolines, it's now considered
+ * normal for a function to call within itself. So
+ * disable this warning for now.
+ */
+#if 0
if (!insn->call_dest) {
WARN_FUNC("can't find call dest symbol at offset 0x%lx",
insn->sec, insn->offset, dest_off);
return -1;
}
+#endif
} else if (rela->sym->type == STT_SECTION) {
insn->call_dest = find_symbol_by_offset(rela->sym->sec,
rela->addend+4);
@@ -678,12 +719,6 @@ static int add_special_section_alts(stru
return ret;
list_for_each_entry_safe(special_alt, tmp, &special_alts, list) {
- alt = malloc(sizeof(*alt));
- if (!alt) {
- WARN("malloc failed");
- ret = -1;
- goto out;
- }
orig_insn = find_insn(file, special_alt->orig_sec,
special_alt->orig_off);
@@ -694,6 +729,10 @@ static int add_special_section_alts(stru
goto out;
}
+ /* Ignore retpoline alternatives. */
+ if (orig_insn->ignore_alts)
+ continue;
+
new_insn = NULL;
if (!special_alt->group || special_alt->new_len) {
new_insn = find_insn(file, special_alt->new_sec,
@@ -719,6 +758,13 @@ static int add_special_section_alts(stru
goto out;
}
+ alt = malloc(sizeof(*alt));
+ if (!alt) {
+ WARN("malloc failed");
+ ret = -1;
+ goto out;
+ }
+
alt->insn = new_insn;
list_add_tail(&alt->list, &orig_insn->alts);
@@ -1035,6 +1081,10 @@ static int decode_sections(struct objtoo
add_ignores(file);
+ ret = add_nospec_ignores(file);
+ if (ret)
+ return ret;
+
ret = add_jump_destinations(file);
if (ret)
return ret;
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -44,7 +44,7 @@ struct instruction {
unsigned int len;
unsigned char type;
unsigned long immediate;
- bool alt_group, visited, dead_end, ignore, hint, save, restore;
+ bool alt_group, visited, dead_end, ignore, hint, save, restore, ignore_alts;
struct symbol *call_dest;
struct instruction *jump_dest;
struct list_head alts;
Patches currently in stable-queue which might be from jpoimboe(a)redhat.com are
queue-4.14/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.14/objtool-detect-jumps-to-retpoline-thunks.patch
queue-4.14/objtool-allow-alternatives-to-be-ignored.patch
queue-4.14/x86-retpoline-add-initial-retpoline-support.patch
This is a note to let you know that I've just added the patch titled
x86/tboot: Unbreak tboot with PTI enabled
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-tboot-unbreak-tboot-with-pti-enabled.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 262b6b30087246abf09d6275eb0c0dc421bcbe38 Mon Sep 17 00:00:00 2001
From: Dave Hansen <dave.hansen(a)linux.intel.com>
Date: Sat, 6 Jan 2018 18:41:14 +0100
Subject: x86/tboot: Unbreak tboot with PTI enabled
From: Dave Hansen <dave.hansen(a)linux.intel.com>
commit 262b6b30087246abf09d6275eb0c0dc421bcbe38 upstream.
This is another case similar to what EFI does: create a new set of
page tables, map some code at a low address, and jump to it. PTI
mistakes this low address for userspace and mistakenly marks it
non-executable in an effort to make it unusable for userspace.
Undo the poison to allow execution.
Fixes: 385ce0ea4c07 ("x86/mm/pti: Add Kconfig")
Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com>
Signed-off-by: Andrea Arcangeli <aarcange(a)redhat.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Alan Cox <gnomes(a)lxorguk.ukuu.org.uk>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Jon Masters <jcm(a)redhat.com>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Andi Kleen <andi(a)firstfloor.org>
Cc: Jeff Law <law(a)redhat.com>
Cc: Paolo Bonzini <pbonzini(a)redhat.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: David" <dwmw(a)amazon.co.uk>
Cc: Nick Clifton <nickc(a)redhat.com>
Link: https://lkml.kernel.org/r/20180108102805.GK25546@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/tboot.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -127,6 +127,7 @@ static int map_tboot_page(unsigned long
p4d = p4d_alloc(&tboot_mm, pgd, vaddr);
if (!p4d)
return -1;
+ pgd->pgd &= ~_PAGE_NX;
pud = pud_alloc(&tboot_mm, p4d, vaddr);
if (!pud)
return -1;
Patches currently in stable-queue which might be from dave.hansen(a)linux.intel.com are
queue-4.14/x86-pti-unbreak-efi-old_memmap.patch
queue-4.14/x86-documentation-add-pti-description.patch
queue-4.14/x86-tboot-unbreak-tboot-with-pti-enabled.patch
This is a note to let you know that I've just added the patch titled
x86/mm/pti: Remove dead logic in pti_user_pagetable_walk*()
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-pti-remove-dead-logic-in-pti_user_pagetable_walk.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 8d56eff266f3e41a6c39926269c4c3f58f881a8e Mon Sep 17 00:00:00 2001
From: Jike Song <albcamus(a)gmail.com>
Date: Tue, 9 Jan 2018 00:03:41 +0800
Subject: x86/mm/pti: Remove dead logic in pti_user_pagetable_walk*()
From: Jike Song <albcamus(a)gmail.com>
commit 8d56eff266f3e41a6c39926269c4c3f58f881a8e upstream.
The following code contains dead logic:
162 if (pgd_none(*pgd)) {
163 unsigned long new_p4d_page = __get_free_page(gfp);
164 if (!new_p4d_page)
165 return NULL;
166
167 if (pgd_none(*pgd)) {
168 set_pgd(pgd, __pgd(_KERNPG_TABLE | __pa(new_p4d_page)));
169 new_p4d_page = 0;
170 }
171 if (new_p4d_page)
172 free_page(new_p4d_page);
173 }
There can't be any difference between two pgd_none(*pgd) at L162 and L167,
so it's always false at L171.
Dave Hansen explained:
Yes, the double-test was part of an optimization where we attempted to
avoid using a global spinlock in the fork() path. We would check for
unallocated mid-level page tables without the lock. The lock was only
taken when we needed to *make* an entry to avoid collisions.
Now that it is all single-threaded, there is no chance of a collision,
no need for a lock, and no need for the re-check.
As all these functions are only called during init, mark them __init as
well.
Fixes: 03f4424f348e ("x86/mm/pti: Add functions to clone kernel PMDs")
Signed-off-by: Jike Song <albcamus(a)gmail.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Alan Cox <gnomes(a)lxorguk.ukuu.org.uk>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Tom Lendacky <thomas.lendacky(a)amd.com>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Jiri Koshina <jikos(a)kernel.org>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Kees Cook <keescook(a)google.com>
Cc: Andi Lutomirski <luto(a)amacapital.net>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Greg KH <gregkh(a)linux-foundation.org>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/20180108160341.3461-1-albcamus@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/mm/pti.c | 32 ++++++--------------------------
1 file changed, 6 insertions(+), 26 deletions(-)
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -149,7 +149,7 @@ pgd_t __pti_set_user_pgd(pgd_t *pgdp, pg
*
* Returns a pointer to a P4D on success, or NULL on failure.
*/
-static p4d_t *pti_user_pagetable_walk_p4d(unsigned long address)
+static __init p4d_t *pti_user_pagetable_walk_p4d(unsigned long address)
{
pgd_t *pgd = kernel_to_user_pgdp(pgd_offset_k(address));
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
@@ -164,12 +164,7 @@ static p4d_t *pti_user_pagetable_walk_p4
if (!new_p4d_page)
return NULL;
- if (pgd_none(*pgd)) {
- set_pgd(pgd, __pgd(_KERNPG_TABLE | __pa(new_p4d_page)));
- new_p4d_page = 0;
- }
- if (new_p4d_page)
- free_page(new_p4d_page);
+ set_pgd(pgd, __pgd(_KERNPG_TABLE | __pa(new_p4d_page)));
}
BUILD_BUG_ON(pgd_large(*pgd) != 0);
@@ -182,7 +177,7 @@ static p4d_t *pti_user_pagetable_walk_p4
*
* Returns a pointer to a PMD on success, or NULL on failure.
*/
-static pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
+static __init pmd_t *pti_user_pagetable_walk_pmd(unsigned long address)
{
gfp_t gfp = (GFP_KERNEL | __GFP_NOTRACK | __GFP_ZERO);
p4d_t *p4d = pti_user_pagetable_walk_p4d(address);
@@ -194,12 +189,7 @@ static pmd_t *pti_user_pagetable_walk_pm
if (!new_pud_page)
return NULL;
- if (p4d_none(*p4d)) {
- set_p4d(p4d, __p4d(_KERNPG_TABLE | __pa(new_pud_page)));
- new_pud_page = 0;
- }
- if (new_pud_page)
- free_page(new_pud_page);
+ set_p4d(p4d, __p4d(_KERNPG_TABLE | __pa(new_pud_page)));
}
pud = pud_offset(p4d, address);
@@ -213,12 +203,7 @@ static pmd_t *pti_user_pagetable_walk_pm
if (!new_pmd_page)
return NULL;
- if (pud_none(*pud)) {
- set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page)));
- new_pmd_page = 0;
- }
- if (new_pmd_page)
- free_page(new_pmd_page);
+ set_pud(pud, __pud(_KERNPG_TABLE | __pa(new_pmd_page)));
}
return pmd_offset(pud, address);
@@ -251,12 +236,7 @@ static __init pte_t *pti_user_pagetable_
if (!new_pte_page)
return NULL;
- if (pmd_none(*pmd)) {
- set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page)));
- new_pte_page = 0;
- }
- if (new_pte_page)
- free_page(new_pte_page);
+ set_pmd(pmd, __pmd(_KERNPG_TABLE | __pa(new_pte_page)));
}
pte = pte_offset_kernel(pmd, address);
Patches currently in stable-queue which might be from albcamus(a)gmail.com are
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
This is a note to let you know that I've just added the patch titled
x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC
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-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.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 9c6a73c75864ad9fa49e5fa6513e4c4071c0e29f Mon Sep 17 00:00:00 2001
From: Tom Lendacky <thomas.lendacky(a)amd.com>
Date: Mon, 8 Jan 2018 16:09:32 -0600
Subject: x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC
From: Tom Lendacky <thomas.lendacky(a)amd.com>
commit 9c6a73c75864ad9fa49e5fa6513e4c4071c0e29f upstream.
With LFENCE now a serializing instruction, use LFENCE_RDTSC in preference
to MFENCE_RDTSC. However, since the kernel could be running under a
hypervisor that does not support writing that MSR, read the MSR back and
verify that the bit has been set successfully. If the MSR can be read
and the bit is set, then set the LFENCE_RDTSC feature, otherwise set the
MFENCE_RDTSC feature.
Signed-off-by: Tom Lendacky <thomas.lendacky(a)amd.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Reviewed-by: Reviewed-by: Borislav Petkov <bp(a)suse.de>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh(a)linux-foundation.org>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Cc: Paul Turner <pjt(a)google.com>
Link: https://lkml.kernel.org/r/20180108220932.12580.52458.stgit@tlendack-t1.amdo…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/kernel/cpu/amd.c | 18 ++++++++++++++++--
2 files changed, 17 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -354,6 +354,7 @@
#define MSR_FAM10H_NODE_ID 0xc001100c
#define MSR_F10H_DECFG 0xc0011029
#define MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT 1
+#define MSR_F10H_DECFG_LFENCE_SERIALIZE BIT_ULL(MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT)
/* K8 MSRs */
#define MSR_K8_TOP_MEM1 0xc001001a
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -829,6 +829,9 @@ static void init_amd(struct cpuinfo_x86
set_cpu_cap(c, X86_FEATURE_K8);
if (cpu_has(c, X86_FEATURE_XMM2)) {
+ unsigned long long val;
+ int ret;
+
/*
* A serializing LFENCE has less overhead than MFENCE, so
* use it for execution serialization. On families which
@@ -839,8 +842,19 @@ static void init_amd(struct cpuinfo_x86
msr_set_bit(MSR_F10H_DECFG,
MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT);
- /* MFENCE stops RDTSC speculation */
- set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
+ /*
+ * Verify that the MSR write was successful (could be running
+ * under a hypervisor) and only then assume that LFENCE is
+ * serializing.
+ */
+ ret = rdmsrl_safe(MSR_F10H_DECFG, &val);
+ if (!ret && (val & MSR_F10H_DECFG_LFENCE_SERIALIZE)) {
+ /* A serializing LFENCE stops RDTSC speculation */
+ set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
+ } else {
+ /* MFENCE stops RDTSC speculation */
+ set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
+ }
}
/*
Patches currently in stable-queue which might be from thomas.lendacky(a)amd.com are
queue-4.14/kvm-vmx-scrub-hardware-gprs-at-vm-exit.patch
queue-4.14/x86-mm-pti-remove-dead-logic-in-pti_user_pagetable_walk.patch
queue-4.14/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.14/x86-alternatives-fix-optimize_nops-checking.patch
queue-4.14/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch