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 4.4-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:
x86-retpoline-checksum32-convert-assembler-indirect-jumps.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 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
@@ -28,7 +28,8 @@
#include <linux/linkage.h>
#include <asm/errno.h>
#include <asm/asm.h>
-
+#include <asm/nospec-branch.h>
+
/*
* computes a partial checksum, e.g. for TCP/UDP fragments
*/
@@ -155,7 +156,7 @@ 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
@@ -437,7 +438,7 @@ 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-4.4/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.4/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.4/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.4/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.4/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.4/x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch
queue-4.4/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.4/x86-retpoline-remove-compile-time-warning.patch
queue-4.4/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.4/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: Add initial retpoline support
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:
x86-retpoline-add-initial-retpoline-support.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 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: David Woodhouse <dwmw(a)amazon.co.uk>
[ 4.4 backport: removed objtool annotation since there is no objtool ]
Signed-off-by: Razvan Ghitulete <rga(a)amazon.de>
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/cpufeature.h | 2
arch/x86/include/asm/nospec-branch.h | 106 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/cpu/common.c | 4 +
arch/x86/lib/Makefile | 1
arch/x86/lib/retpoline.S | 48 +++++++++++++++
8 files changed, 209 insertions(+)
create mode 100644 arch/x86/include/asm/nospec-branch.h
create mode 100644 arch/x86/lib/retpoline.S
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -379,6 +379,19 @@ 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.
+
if X86_32
config X86_EXTENDED_PLATFORM
bool "Support for extended (non-PC) x86 platforms"
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -189,6 +189,16 @@ KBUILD_CFLAGS += -fno-asynchronous-unwin
KBUILD_CFLAGS += $(mflags-y)
KBUILD_AFLAGS += $(mflags-y)
+# Avoid indirect branches in kernel to deal with Spectre
+ifdef CONFIG_RETPOLINE
+ RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
+ ifneq ($(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
@@ -10,7 +10,32 @@
#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/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -200,6 +200,8 @@
#define X86_FEATURE_HWP_PKG_REQ ( 7*32+14) /* Intel HWP_PKG_REQ */
#define X86_FEATURE_INTEL_PT ( 7*32+15) /* Intel Processor Trace */
+#define X86_FEATURE_RETPOLINE ( 7*32+29) /* Generic Retpoline mitigation for Spectre variant 2 */
+#define X86_FEATURE_RETPOLINE_AMD ( 7*32+30) /* AMD Retpoline mitigation for Spectre variant 2 */
/* Because the ALTERNATIVE scheme is for members of the X86_FEATURE club... */
#define X86_FEATURE_KAISER ( 7*32+31) /* CONFIG_PAGE_TABLE_ISOLATION w/o nokaiser */
--- /dev/null
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -0,0 +1,106 @@
+/* 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/cpufeature.h>
+
+#ifdef __ASSEMBLY__
+
+/*
+ * 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
+ 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
+ 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__ */
+
+#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 \
+ 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 $4, %%esp;\n" \
+ " pushl %[thunk_target];\n" \
+ " ret;\n" \
+ " .align 16\n" \
+ "904: call 901b;\n", \
+ X86_FEATURE_RETPOLINE)
+
+# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
+#else /* No retpoline */
+# define CALL_NOSPEC "call *%[thunk_target]\n"
+# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
+#endif
+
+#endif /* __ASSEMBLY__ */
+#endif /* __NOSPEC_BRANCH_H__ */
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -837,6 +837,10 @@ static void __init early_identify_cpu(st
setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+#ifdef CONFIG_RETPOLINE
+ setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
+#endif
+
fpu__init_system(c);
#ifdef CONFIG_X86_32
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -21,6 +21,7 @@ lib-y += usercopy_$(BITS).o usercopy.o g
lib-y += memcpy_$(BITS).o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o
+lib-$(CONFIG_RETPOLINE) += retpoline.o
obj-y += msr.o msr-reg.o msr-reg-export.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/cpufeature.h>
+#include <asm/alternative-asm.h>
+#include <asm-generic/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-4.4/x86-spectre-add-boot-time-option-to-select-spectre-v2-mitigation.patch
queue-4.4/x86-retpoline-irq32-convert-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-hyperv-convert-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-entry-convert-entry-assembler-indirect-jumps.patch
queue-4.4/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.4/x86-retpoline-ftrace-convert-ftrace-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-crypto-convert-crypto-assembler-indirect-jumps.patch
queue-4.4/x86-retpoline-xen-convert-xen-hypercall-indirect-jumps.patch
queue-4.4/x86-retpoline-checksum32-convert-assembler-indirect-jumps.patch
queue-4.4/x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch
queue-4.4/x86-retpoline-fill-return-stack-buffer-on-vmexit.patch
queue-4.4/x86-retpoline-remove-compile-time-warning.patch
queue-4.4/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
queue-4.4/x86-retpoline-add-initial-retpoline-support.patch
On Wed, Jan 17, 2018 at 10:38:30AM +0000, Harsh Shandilya wrote:
> On Wed 17 Jan, 2018, 3:11 PM Greg KH, <gregkh(a)linuxfoundation.org> wrote:
>
> > I'm announcing the release of the 3.18.92 kernel.
> >
> > All users of the 3.18 kernel series must upgrade.
> >
> > The updated 3.18.y git tree can be found at:
> > git://
> > git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
> > linux-3.18.y
> > and can be browsed at the normal kernel.org git web browser:
> >
> > http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=summary
> >
> > thanks,
> >
> > greg k-h
> >
>
> Builds and boots on the OnePlus 3T, no regressions noticed in general usage.
Great, thanks for testing and letting me know.
greg k-h
This is a note to let you know that I've just added the patch titled
x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier
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:
x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.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 b8b7abaed7a49b350f8ba659ddc264b04931d581 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto(a)kernel.org>
Date: Sun, 17 Sep 2017 09:03:50 -0700
Subject: x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier
From: Andy Lutomirski <luto(a)kernel.org>
commit b8b7abaed7a49b350f8ba659ddc264b04931d581 upstream.
Otherwise we might have the PCID feature bit set during cpu_init().
This is just for robustness. I haven't seen any actual bugs here.
Signed-off-by: Andy Lutomirski <luto(a)kernel.org>
Cc: Borislav Petkov <bpetkov(a)suse.de>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Fixes: cba4671af755 ("x86/mm: Disable PCID on 32-bit kernels")
Link: http://lkml.kernel.org/r/b16dae9d6b0db5d9801ddbebbfd83384097c61f3.150566353…
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 8 --------
arch/x86/kernel/cpu/common.c | 8 ++++++++
2 files changed, 8 insertions(+), 8 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -22,14 +22,6 @@
void __init check_bugs(void)
{
-#ifdef CONFIG_X86_32
- /*
- * Regardless of whether PCID is enumerated, the SDM says
- * that it can't be enabled in 32-bit mode.
- */
- setup_clear_cpu_cap(X86_FEATURE_PCID);
-#endif
-
identify_boot_cpu();
if (!IS_ENABLED(CONFIG_SMP)) {
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -838,6 +838,14 @@ static void __init early_identify_cpu(st
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
fpu__init_system(c);
+
+#ifdef CONFIG_X86_32
+ /*
+ * Regardless of whether PCID is enumerated, the SDM says
+ * that it can't be enabled in 32-bit mode.
+ */
+ setup_clear_cpu_cap(X86_FEATURE_PCID);
+#endif
}
void __init early_cpu_init(void)
Patches currently in stable-queue which might be from luto(a)kernel.org are
queue-4.4/x86-asm-use-register-variable-to-get-stack-pointer-value.patch
queue-4.4/x86-mm-32-move-setup_clear_cpu_cap-x86_feature_pcid-earlier.patch
queue-4.4/x86-asm-make-asm-alternative.h-safe-from-assembly.patch
This is a note to let you know that I've just added the patch titled
x86/kbuild: enable modversions for symbols exported from asm
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:
x86-kbuild-enable-modversions-for-symbols-exported-from-asm.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 334bb773876403eae3457d81be0b8ea70f8e4ccc Mon Sep 17 00:00:00 2001
From: Adam Borowski <kilobyte(a)angband.pl>
Date: Sun, 11 Dec 2016 02:09:18 +0100
Subject: x86/kbuild: enable modversions for symbols exported from asm
From: Adam Borowski <kilobyte(a)angband.pl>
commit 334bb773876403eae3457d81be0b8ea70f8e4ccc upstream.
Commit 4efca4ed ("kbuild: modversions for EXPORT_SYMBOL() for asm") adds
modversion support for symbols exported from asm files. Architectures
must include C-style declarations for those symbols in asm/asm-prototypes.h
in order for them to be versioned.
Add these declarations for x86, and an architecture-independent file that
can be used for common symbols.
With f27c2f6 reverting 8ab2ae6 ("default exported asm symbols to zero") we
produce a scary warning on x86, this commit fixes that.
Signed-off-by: Adam Borowski <kilobyte(a)angband.pl>
Tested-by: Kalle Valo <kvalo(a)codeaurora.org>
Acked-by: Nicholas Piggin <npiggin(a)gmail.com>
Tested-by: Peter Wu <peter(a)lekensteyn.nl>
Tested-by: Oliver Hartkopp <socketcan(a)hartkopp.net>
Signed-off-by: Michal Marek <mmarek(a)suse.com>
Signed-off-by: Razvan Ghitulete <rga(a)amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/asm-prototypes.h | 16 ++++++++++++++++
include/asm-generic/asm-prototypes.h | 7 +++++++
2 files changed, 23 insertions(+)
--- /dev/null
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -0,0 +1,16 @@
+#include <asm/ftrace.h>
+#include <asm/uaccess.h>
+#include <asm/string.h>
+#include <asm/page.h>
+#include <asm/checksum.h>
+
+#include <asm-generic/asm-prototypes.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/special_insns.h>
+#include <asm/preempt.h>
+
+#ifndef CONFIG_X86_CMPXCHG64
+extern void cmpxchg8b_emu(void);
+#endif
--- /dev/null
+++ b/include/asm-generic/asm-prototypes.h
@@ -0,0 +1,7 @@
+#include <linux/bitops.h>
+extern void *__memset(void *, int, __kernel_size_t);
+extern void *__memcpy(void *, const void *, __kernel_size_t);
+extern void *__memmove(void *, const void *, __kernel_size_t);
+extern void *memset(void *, int, __kernel_size_t);
+extern void *memcpy(void *, const void *, __kernel_size_t);
+extern void *memmove(void *, const void *, __kernel_size_t);
Patches currently in stable-queue which might be from kilobyte(a)angband.pl are
queue-4.4/x86-kbuild-enable-modversions-for-symbols-exported-from-asm.patch
This is a note to let you know that I've just added the patch titled
x86/cpu/AMD: Make LFENCE a serializing instruction
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:
x86-cpu-amd-make-lfence-a-serializing-instruction.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 e4d0e84e490790798691aaa0f2e598637f1867ec Mon Sep 17 00:00:00 2001
From: Tom Lendacky <thomas.lendacky(a)amd.com>
Date: Mon, 8 Jan 2018 16:09:21 -0600
Subject: x86/cpu/AMD: Make LFENCE a serializing instruction
From: Tom Lendacky <thomas.lendacky(a)amd.com>
commit e4d0e84e490790798691aaa0f2e598637f1867ec upstream.
To aid in speculation control, make LFENCE a serializing instruction
since it has less overhead than MFENCE. This is done by setting bit 1
of MSR 0xc0011029 (DE_CFG). Some families that support LFENCE do not
have this MSR. For these families, the LFENCE instruction is already
serializing.
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/20180108220921.12580.71694.stgit@tlendack-t1.amdo…
Signed-off-by: Razvan Ghitulete <rga(a)amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/msr-index.h | 2 ++
arch/x86/kernel/cpu/amd.c | 10 ++++++++++
2 files changed, 12 insertions(+)
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -330,6 +330,8 @@
#define FAM10H_MMIO_CONF_BASE_MASK 0xfffffffULL
#define FAM10H_MMIO_CONF_BASE_SHIFT 20
#define MSR_FAM10H_NODE_ID 0xc001100c
+#define MSR_F10H_DECFG 0xc0011029
+#define MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT 1
/* K8 MSRs */
#define MSR_K8_TOP_MEM1 0xc001001a
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -746,6 +746,16 @@ static void init_amd(struct cpuinfo_x86
set_cpu_cap(c, X86_FEATURE_K8);
if (cpu_has_xmm2) {
+ /*
+ * A serializing LFENCE has less overhead than MFENCE, so
+ * use it for execution serialization. On families which
+ * don't have that MSR, LFENCE is already serializing.
+ * msr_set_bit() uses the safe accessors, too, even if the MSR
+ * is not present.
+ */
+ msr_set_bit(MSR_F10H_DECFG,
+ MSR_F10H_DECFG_LFENCE_SERIALIZE_BIT);
+
/* 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-4.4/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.4/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.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 4.4-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:
x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.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 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: Razvan Ghitulete <rga(a)amazon.de>
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
@@ -332,6 +332,7 @@
#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
@@ -746,6 +746,9 @@ static void init_amd(struct cpuinfo_x86
set_cpu_cap(c, X86_FEATURE_K8);
if (cpu_has_xmm2) {
+ unsigned long long val;
+ int ret;
+
/*
* A serializing LFENCE has less overhead than MFENCE, so
* use it for execution serialization. On families which
@@ -756,8 +759,19 @@ 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-4.4/x86-cpu-amd-make-lfence-a-serializing-instruction.patch
queue-4.4/x86-cpu-amd-use-lfence_rdtsc-in-preference-to-mfence_rdtsc.patch
This is a note to let you know that I've just added the patch titled
x86/asm: Use register variable to get stack pointer value
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:
x86-asm-use-register-variable-to-get-stack-pointer-value.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 196bd485ee4f03ce4c690bfcf38138abfcd0a4bc Mon Sep 17 00:00:00 2001
From: Andrey Ryabinin <aryabinin(a)virtuozzo.com>
Date: Fri, 29 Sep 2017 17:15:36 +0300
Subject: x86/asm: Use register variable to get stack pointer value
From: Andrey Ryabinin <aryabinin(a)virtuozzo.com>
commit 196bd485ee4f03ce4c690bfcf38138abfcd0a4bc upstream.
Currently we use current_stack_pointer() function to get the value
of the stack pointer register. Since commit:
f5caf621ee35 ("x86/asm: Fix inline asm call constraints for Clang")
... we have a stack register variable declared. It can be used instead of
current_stack_pointer() function which allows to optimize away some
excessive "mov %rsp, %<dst>" instructions:
-mov %rsp,%rdx
-sub %rdx,%rax
-cmp $0x3fff,%rax
-ja ffffffff810722fd <ist_begin_non_atomic+0x2d>
+sub %rsp,%rax
+cmp $0x3fff,%rax
+ja ffffffff810722fa <ist_begin_non_atomic+0x2a>
Remove current_stack_pointer(), rename __asm_call_sp to current_stack_pointer
and use it instead of the removed function.
Signed-off-by: Andrey Ryabinin <aryabinin(a)virtuozzo.com>
Reviewed-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
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/20170929141537.29167-1-aryabinin@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo(a)kernel.org>
[dwmw2: We want ASM_CALL_CONSTRAINT for retpoline]
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.ku>
Signed-off-by: Razvan Ghitulete <rga(a)amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/asm.h | 11 +++++++++++
arch/x86/include/asm/thread_info.h | 11 -----------
arch/x86/kernel/irq_32.c | 6 +++---
arch/x86/kernel/traps.c | 2 +-
4 files changed, 15 insertions(+), 15 deletions(-)
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -105,4 +105,15 @@
/* For C file, we already have NOKPROBE_SYMBOL macro */
#endif
+#ifndef __ASSEMBLY__
+/*
+ * This output constraint should be used for any inline asm which has a "call"
+ * instruction. Otherwise the asm may be inserted before the frame pointer
+ * gets set up by the containing function. If you forget to do this, objtool
+ * may print a "call without frame pointer save/setup" warning.
+ */
+register unsigned long current_stack_pointer asm(_ASM_SP);
+#define ASM_CALL_CONSTRAINT "+r" (current_stack_pointer)
+#endif
+
#endif /* _ASM_X86_ASM_H */
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -166,17 +166,6 @@ static inline struct thread_info *curren
return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);
}
-static inline unsigned long current_stack_pointer(void)
-{
- unsigned long sp;
-#ifdef CONFIG_X86_64
- asm("mov %%rsp,%0" : "=g" (sp));
-#else
- asm("mov %%esp,%0" : "=g" (sp));
-#endif
- return sp;
-}
-
#else /* !__ASSEMBLY__ */
#ifdef CONFIG_X86_64
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -65,7 +65,7 @@ static void call_on_stack(void *func, vo
static inline void *current_stack(void)
{
- return (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1));
+ return (void *)(current_stack_pointer & ~(THREAD_SIZE - 1));
}
static inline int execute_on_irq_stack(int overflow, struct irq_desc *desc)
@@ -89,7 +89,7 @@ static inline int execute_on_irq_stack(i
/* Save the next esp at the bottom of the stack */
prev_esp = (u32 *)irqstk;
- *prev_esp = current_stack_pointer();
+ *prev_esp = current_stack_pointer;
if (unlikely(overflow))
call_on_stack(print_stack_overflow, isp);
@@ -142,7 +142,7 @@ void do_softirq_own_stack(void)
/* Push the previous esp onto the stack */
prev_esp = (u32 *)irqstk;
- *prev_esp = current_stack_pointer();
+ *prev_esp = current_stack_pointer;
call_on_stack(__do_softirq, isp);
}
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -166,7 +166,7 @@ void ist_begin_non_atomic(struct pt_regs
* from double_fault.
*/
BUG_ON((unsigned long)(current_top_of_stack() -
- current_stack_pointer()) >= THREAD_SIZE);
+ current_stack_pointer) >= THREAD_SIZE);
preempt_enable_no_resched();
}
Patches currently in stable-queue which might be from aryabinin(a)virtuozzo.com are
queue-4.4/x86-asm-use-register-variable-to-get-stack-pointer-value.patch
This is a note to let you know that I've just added the patch titled
kconfig.h: use __is_defined() to check if MODULE is defined
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:
kconfig.h-use-__is_defined-to-check-if-module-is-defined.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 4f920843d248946545415c1bf6120942048708ed Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.masahiro(a)socionext.com>
Date: Tue, 14 Jun 2016 14:58:54 +0900
Subject: kconfig.h: use __is_defined() to check if MODULE is defined
From: Masahiro Yamada <yamada.masahiro(a)socionext.com>
commit 4f920843d248946545415c1bf6120942048708ed upstream.
The macro MODULE is not a config option, it is a per-file build
option. So, config_enabled(MODULE) is not sensible. (There is
another case in include/linux/export.h, where config_enabled() is
used against a non-config option.)
This commit renames some macros in include/linux/kconfig.h for the
use for non-config macros and replaces config_enabled(MODULE) with
__is_defined(MODULE).
I am keeping config_enabled() because it is still referenced from
some places, but I expect it would be deprecated in the future.
Signed-off-by: Masahiro Yamada <yamada.masahiro(a)socionext.com>
Signed-off-by: Michal Marek <mmarek(a)suse.com>
Signed-off-by: Razvan Ghitulete <rga(a)amazon.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
include/linux/kconfig.h | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- a/include/linux/kconfig.h
+++ b/include/linux/kconfig.h
@@ -17,10 +17,11 @@
* the last step cherry picks the 2nd arg, we get a zero.
*/
#define __ARG_PLACEHOLDER_1 0,
-#define config_enabled(cfg) _config_enabled(cfg)
-#define _config_enabled(value) __config_enabled(__ARG_PLACEHOLDER_##value)
-#define __config_enabled(arg1_or_junk) ___config_enabled(arg1_or_junk 1, 0)
-#define ___config_enabled(__ignored, val, ...) val
+#define config_enabled(cfg) ___is_defined(cfg)
+#define __is_defined(x) ___is_defined(x)
+#define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val)
+#define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0)
+#define __take_second_arg(__ignored, val, ...) val
/*
* IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
@@ -42,7 +43,7 @@
* built-in code when CONFIG_FOO is set to 'm'.
*/
#define IS_REACHABLE(option) (config_enabled(option) || \
- (config_enabled(option##_MODULE) && config_enabled(MODULE)))
+ (config_enabled(option##_MODULE) && __is_defined(MODULE)))
/*
* IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
Patches currently in stable-queue which might be from yamada.masahiro(a)socionext.com are
queue-4.4/kconfig.h-use-__is_defined-to-check-if-module-is-defined.patch