This is a note to let you know that I've just added the patch titled
x86/speculation: Use Indirect Branch Prediction Barrier in context switch
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86speculation_Use_Indirect_Branch_Prediction_Barrier_in_context_switch.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/speculation: Use Indirect Branch Prediction Barrier in context switch
From: Tim Chen tim.c.chen(a)linux.intel.com
Date: Mon Jan 29 22:04:47 2018 +0000
From: Tim Chen tim.c.chen(a)linux.intel.com
commit 18bf3c3ea8ece8f03b6fc58508f2dfd23c7711c7
Flush indirect branches when switching into a process that marked itself
non dumpable. This protects high value processes like gpg better,
without having too high performance overhead.
If done naïvely, we could switch to a kernel idle thread and then back
to the original process, such as:
process A -> idle -> process A
In such scenario, we do not have to do IBPB here even though the process
is non-dumpable, as we are switching back to the same process after a
hiatus.
To avoid the redundant IBPB, which is expensive, we track the last mm
user context ID. The cost is to have an extra u64 mm context id to track
the last mm we were using before switching to the init_mm used by idle.
Avoiding the extra IBPB is probably worth the extra memory for this
common scenario.
For those cases where tlb_defer_switch_to_init_mm() returns true (non
PCID), lazy tlb will defer switch to init_mm, so we will not be changing
the mm for the process A -> idle -> process A switch. So IBPB will be
skipped for this case.
Thanks to the reviewers and Andy Lutomirski for the suggestion of
using ctx_id which got rid of the problem of mm pointer recycling.
Signed-off-by: Tim Chen <tim.c.chen(a)linux.intel.com>
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: ak(a)linux.intel.com
Cc: karahmed(a)amazon.de
Cc: arjan(a)linux.intel.com
Cc: torvalds(a)linux-foundation.org
Cc: linux(a)dominikbrodowski.net
Cc: peterz(a)infradead.org
Cc: bp(a)alien8.de
Cc: luto(a)kernel.org
Cc: pbonzini(a)redhat.com
Cc: gregkh(a)linux-foundation.org
Link: https://lkml.kernel.org/r/1517263487-3708-1-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/tlbflush.h | 2 ++
arch/x86/mm/tlb.c | 33 ++++++++++++++++++++++++++++++++-
2 files changed, 34 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -174,6 +174,8 @@ struct tlb_state {
struct mm_struct *loaded_mm;
u16 loaded_mm_asid;
u16 next_asid;
+ /* last user mm's ctx id */
+ u64 last_ctx_id;
/*
* We can be in one of several states:
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -6,13 +6,14 @@
#include <linux/interrupt.h>
#include <linux/export.h>
#include <linux/cpu.h>
+#include <linux/debugfs.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
+#include <asm/nospec-branch.h>
#include <asm/cache.h>
#include <asm/apic.h>
#include <asm/uv/uv.h>
-#include <linux/debugfs.h>
/*
* TLB flushing, formerly SMP-only
@@ -247,6 +248,27 @@ void switch_mm_irqs_off(struct mm_struct
} else {
u16 new_asid;
bool need_flush;
+ u64 last_ctx_id = this_cpu_read(cpu_tlbstate.last_ctx_id);
+
+ /*
+ * Avoid user/user BTB poisoning by flushing the branch
+ * predictor when switching between processes. This stops
+ * one process from doing Spectre-v2 attacks on another.
+ *
+ * As an optimization, flush indirect branches only when
+ * switching into processes that disable dumping. This
+ * protects high value processes like gpg, without having
+ * too high performance overhead. IBPB is *expensive*!
+ *
+ * This will not flush branches when switching into kernel
+ * threads. It will also not flush if we switch to idle
+ * thread and back to the same process. It will flush if we
+ * switch to a different non-dumpable process.
+ */
+ if (tsk && tsk->mm &&
+ tsk->mm->context.ctx_id != last_ctx_id &&
+ get_dumpable(tsk->mm) != SUID_DUMP_USER)
+ indirect_branch_prediction_barrier();
if (IS_ENABLED(CONFIG_VMAP_STACK)) {
/*
@@ -292,6 +314,14 @@ void switch_mm_irqs_off(struct mm_struct
trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, 0);
}
+ /*
+ * Record last user mm's context id, so we can avoid
+ * flushing branch buffer with IBPB if we switch back
+ * to the same user.
+ */
+ if (next != &init_mm)
+ this_cpu_write(cpu_tlbstate.last_ctx_id, next->context.ctx_id);
+
this_cpu_write(cpu_tlbstate.loaded_mm, next);
this_cpu_write(cpu_tlbstate.loaded_mm_asid, new_asid);
}
@@ -369,6 +399,7 @@ void initialize_tlbstate_and_flush(void)
write_cr3(build_cr3(mm->pgd, 0));
/* Reinitialize tlbstate. */
+ this_cpu_write(cpu_tlbstate.last_ctx_id, mm->context.ctx_id);
this_cpu_write(cpu_tlbstate.loaded_mm_asid, 0);
this_cpu_write(cpu_tlbstate.next_asid, 1);
this_cpu_write(cpu_tlbstate.ctxs[0].ctx_id, mm->context.ctx_id);
Patches currently in stable-queue which might be from tim.c.chen(a)linux.intel.com are
queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch
queue-4.15/x86speculation_Use_Indirect_Branch_Prediction_Barrier_in_context_switch.patch
queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch
queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch
queue-4.15/x86paravirt_Remove_noreplace-paravirt_cmdline_option.patch
queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch
queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch
queue-4.15/x86alternative_Print_unadorned_pointers.patch
queue-4.15/KVMVMX_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch
queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch
queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch
queue-4.15/KVMSVM_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/KVMx86_Add_IBPB_support.patch
queue-4.15/KVMVMX_Emulate_MSR_IA32_ARCH_CAPABILITIES.patch
queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch
queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch
queue-4.15/x86nospec_Fix_header_guards_names.patch
queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch
queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch
queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch
This is a note to let you know that I've just added the patch titled
x86/speculation: Fix typo IBRS_ATT, which should be IBRS_ALL
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86speculation_Fix_typo_IBRS_ATT_which_should_be_IBRS_ALL.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/speculation: Fix typo IBRS_ATT, which should be IBRS_ALL
From: Darren Kenny darren.kenny(a)oracle.com
Date: Fri Feb 2 19:12:20 2018 +0000
From: Darren Kenny darren.kenny(a)oracle.com
commit af189c95a371b59f493dbe0f50c0a09724868881
Fixes: 117cc7a908c83 ("x86/retpoline: Fill return stack buffer on vmexit")
Signed-off-by: Darren Kenny <darren.kenny(a)oracle.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk(a)oracle.com>
Cc: Tom Lendacky <thomas.lendacky(a)amd.com>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Borislav Petkov <bp(a)alien8.de>
Cc: Masami Hiramatsu <mhiramat(a)kernel.org>
Cc: Arjan van de Ven <arjan(a)linux.intel.com>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Link: https://lkml.kernel.org/r/20180202191220.blvgkgutojecxr3b@starbug-vm.ie.ora…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -150,7 +150,7 @@ extern char __indirect_thunk_end[];
* 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.
+ * CPUs with IBRS_ALL *might* it be avoided.
*/
static inline void vmexit_fill_RSB(void)
{
Patches currently in stable-queue which might be from darren.kenny(a)oracle.com are
queue-4.15/KVMVMX_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/KVMSVM_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/KVMVMX_Emulate_MSR_IA32_ARCH_CAPABILITIES.patch
queue-4.15/x86speculation_Fix_typo_IBRS_ATT_which_should_be_IBRS_ALL.patch
This is a note to let you know that I've just added the patch titled
x86/spectre: Report get_user mitigation for spectre_v1
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86spectre_Report_get_user_mitigation_for_spectre_v1.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/spectre: Report get_user mitigation for spectre_v1
From: Dan Williams dan.j.williams(a)intel.com
Date: Mon Jan 29 17:03:21 2018 -0800
From: Dan Williams dan.j.williams(a)intel.com
commit edfbae53dab8348fca778531be9f4855d2ca0360
Reflect the presence of get_user(), __get_user(), and 'syscall' protections
in sysfs. The expectation is that new and better tooling will allow the
kernel to grow more usages of array_index_nospec(), for now, only claim
mitigation for __user pointer de-references.
Reported-by: Jiri Slaby <jslaby(a)suse.cz>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: linux-arch(a)vger.kernel.org
Cc: kernel-hardening(a)lists.openwall.com
Cc: gregkh(a)linuxfoundation.org
Cc: torvalds(a)linux-foundation.org
Cc: alan(a)linux.intel.com
Link: https://lkml.kernel.org/r/151727420158.33451.11658324346540434635.stgit@dwi…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -297,7 +297,7 @@ ssize_t cpu_show_spectre_v1(struct devic
{
if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1))
return sprintf(buf, "Not affected\n");
- return sprintf(buf, "Vulnerable\n");
+ return sprintf(buf, "Mitigation: __user pointer sanitization\n");
}
ssize_t cpu_show_spectre_v2(struct device *dev,
Patches currently in stable-queue which might be from jslaby(a)suse.cz are
queue-4.15/x86spectre_Report_get_user_mitigation_for_spectre_v1.patch
This is a note to let you know that I've just added the patch titled
x86/spectre: Fix spelling mistake: "vunerable"-> "vulnerable"
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86spectre_Fix_spelling_mistake_vunerable-_vulnerable.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/spectre: Fix spelling mistake: "vunerable"-> "vulnerable"
From: Colin Ian King colin.king(a)canonical.com
Date: Tue Jan 30 19:32:18 2018 +0000
From: Colin Ian King colin.king(a)canonical.com
commit e698dcdfcda41efd0984de539767b4cddd235f1e
Trivial fix to spelling mistake in pr_err error message text.
Signed-off-by: Colin Ian King <colin.king(a)canonical.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: kernel-janitors(a)vger.kernel.org
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Borislav Petkov <bp(a)suse.de>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Link: https://lkml.kernel.org/r/20180130193218.9271-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -103,7 +103,7 @@ bool retpoline_module_ok(bool has_retpol
if (spectre_v2_enabled == SPECTRE_V2_NONE || has_retpoline)
return true;
- pr_err("System may be vunerable to spectre v2\n");
+ pr_err("System may be vulnerable to spectre v2\n");
spectre_v2_bad_module = true;
return false;
}
Patches currently in stable-queue which might be from colin.king(a)canonical.com are
queue-4.15/x86spectre_Fix_spelling_mistake_vunerable-_vulnerable.patch
This is a note to let you know that I've just added the patch titled
x86/spectre: Check CONFIG_RETPOLINE in command line parser
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86spectre_Check_CONFIG_RETPOLINE_in_command_line_parser.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/spectre: Check CONFIG_RETPOLINE in command line parser
From: Dou Liyang douly.fnst(a)cn.fujitsu.com
Date: Tue Jan 30 14:13:50 2018 +0800
From: Dou Liyang douly.fnst(a)cn.fujitsu.com
commit 9471eee9186a46893726e22ebb54cade3f9bc043
The spectre_v2 option 'auto' does not check whether CONFIG_RETPOLINE is
enabled. As a consequence it fails to emit the appropriate warning and sets
feature flags which have no effect at all.
Add the missing IS_ENABLED() check.
Fixes: da285121560e ("x86/spectre: Add boot time option to select Spectre v2 mitigation")
Signed-off-by: Dou Liyang <douly.fnst(a)cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: ak(a)linux.intel.com
Cc: peterz(a)infradead.org
Cc: Tomohiro" <misono.tomohiro(a)jp.fujitsu.com>
Cc: dave.hansen(a)intel.com
Cc: bp(a)alien8.de
Cc: arjan(a)linux.intel.com
Cc: dwmw(a)amazon.co.uk
Cc: stable(a)vger.kernel.org
Link: https://lkml.kernel.org/r/f5892721-7528-3647-08fb-f8d10e65ad87@cn.fujitsu.c…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -213,10 +213,10 @@ static void __init spectre_v2_select_mit
return;
case SPECTRE_V2_CMD_FORCE:
- /* FALLTRHU */
case SPECTRE_V2_CMD_AUTO:
- goto retpoline_auto;
-
+ if (IS_ENABLED(CONFIG_RETPOLINE))
+ goto retpoline_auto;
+ break;
case SPECTRE_V2_CMD_RETPOLINE_AMD:
if (IS_ENABLED(CONFIG_RETPOLINE))
goto retpoline_amd;
Patches currently in stable-queue which might be from douly.fnst(a)cn.fujitsu.com are
queue-4.15/x86spectre_Check_CONFIG_RETPOLINE_in_command_line_parser.patch
This is a note to let you know that I've just added the patch titled
x86/retpoline: Avoid retpolines for built-in __init functions
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86retpoline_Avoid_retpolines_for_built-in___init_functions.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/retpoline: Avoid retpolines for built-in __init functions
From: David Woodhouse dwmw(a)amazon.co.uk
Date: Thu Feb 1 11:27:20 2018 +0000
From: David Woodhouse dwmw(a)amazon.co.uk
commit 66f793099a636862a71c59d4a6ba91387b155e0c
There's no point in building init code with retpolines, since it runs before
any potentially hostile userspace does. And before the retpoline is actually
ALTERNATIVEd into place, for much of it.
Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: karahmed(a)amazon.de
Cc: peterz(a)infradead.org
Cc: bp(a)alien8.de
Link: https://lkml.kernel.org/r/1517484441-1420-2-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
include/linux/init.h | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -5,6 +5,13 @@
#include <linux/compiler.h>
#include <linux/types.h>
+/* Built-in __init functions needn't be compiled with retpoline */
+#if defined(RETPOLINE) && !defined(MODULE)
+#define __noretpoline __attribute__((indirect_branch("keep")))
+#else
+#define __noretpoline
+#endif
+
/* These macros are used to mark some functions or
* initialized data (doesn't apply to uninitialized data)
* as `initialization' functions. The kernel can take this
@@ -40,7 +47,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
-#define __init __section(.init.text) __cold __latent_entropy
+#define __init __section(.init.text) __cold __latent_entropy __noretpoline
#define __initdata __section(.init.data)
#define __initconst __section(.init.rodata)
#define __exitdata __section(.exit.data)
Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are
queue-4.15/x86spectre_Simplify_spectre_v2_command_line_parsing.patch
queue-4.15/x86pti_Mark_constant_arrays_as___initconst.patch
queue-4.15/x86pti_Do_not_enable_PTI_on_CPUs_which_are_not_vulnerable_to_Meltdown.patch
queue-4.15/x86speculation_Use_Indirect_Branch_Prediction_Barrier_in_context_switch.patch
queue-4.15/x86cpuid_Fix_up_virtual_IBRSIBPBSTIBP_feature_bits_on_Intel.patch
queue-4.15/x86spectre_Fix_spelling_mistake_vunerable-_vulnerable.patch
queue-4.15/x86cpufeature_Blacklist_SPEC_CTRLPRED_CMD_on_early_Spectre_v2_microcodes.patch
queue-4.15/x86cpufeatures_Add_Intel_feature_bits_for_Speculation_Control.patch
queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch
queue-4.15/x86spectre_Check_CONFIG_RETPOLINE_in_command_line_parser.patch
queue-4.15/x86msr_Add_definitions_for_new_speculation_control_MSRs.patch
queue-4.15/KVMVMX_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/x86cpufeatures_Add_CPUID_7_EDX_CPUID_leaf.patch
queue-4.15/x86cpufeatures_Add_AMD_feature_bits_for_Speculation_Control.patch
queue-4.15/KVMSVM_Allow_direct_access_to_MSR_IA32_SPEC_CTRL.patch
queue-4.15/KVMx86_Add_IBPB_support.patch
queue-4.15/KVMVMX_Emulate_MSR_IA32_ARCH_CAPABILITIES.patch
queue-4.15/x86speculation_Add_basic_IBPB_(Indirect_Branch_Prediction_Barrier)_support.patch
queue-4.15/x86speculation_Simplify_indirect_branch_prediction_barrier().patch
queue-4.15/x86speculation_Fix_typo_IBRS_ATT_which_should_be_IBRS_ALL.patch
queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch
queue-4.15/x86retpoline_Simplify_vmexit_fill_RSB().patch
queue-4.15/x86cpufeatures_Clean_up_Spectre_v2_related_CPUID_flags.patch
queue-4.15/KVMx86_Update_the_reverse_cpuid_list_to_include_CPUID_7_EDX.patch
queue-4.15/x86retpoline_Avoid_retpolines_for_built-in___init_functions.patch
This is a note to let you know that I've just added the patch titled
x86/paravirt: Remove 'noreplace-paravirt' cmdline option
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86paravirt_Remove_noreplace-paravirt_cmdline_option.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/paravirt: Remove 'noreplace-paravirt' cmdline option
From: Josh Poimboeuf jpoimboe(a)redhat.com
Date: Tue Jan 30 22:13:33 2018 -0600
From: Josh Poimboeuf jpoimboe(a)redhat.com
commit 12c69f1e94c89d40696e83804dd2f0965b5250cd
The 'noreplace-paravirt' option disables paravirt patching, leaving the
original pv indirect calls in place.
That's highly incompatible with retpolines, unless we want to uglify
paravirt even further and convert the paravirt calls to retpolines.
As far as I can tell, the option doesn't seem to be useful for much
other than introducing surprising corner cases and making the kernel
vulnerable to Spectre v2. It was probably a debug option from the early
paravirt days. So just remove it.
Signed-off-by: Josh Poimboeuf <jpoimboe(a)redhat.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Reviewed-by: Juergen Gross <jgross(a)suse.com>
Cc: Andrea Arcangeli <aarcange(a)redhat.com>
Cc: Peter Zijlstra <peterz(a)infradead.org>
Cc: Andi Kleen <ak(a)linux.intel.com>
Cc: Ashok Raj <ashok.raj(a)intel.com>
Cc: Greg KH <gregkh(a)linuxfoundation.org>
Cc: Jun Nakajima <jun.nakajima(a)intel.com>
Cc: Tim Chen <tim.c.chen(a)linux.intel.com>
Cc: Rusty Russell <rusty(a)rustcorp.com.au>
Cc: Dave Hansen <dave.hansen(a)intel.com>
Cc: Asit Mallick <asit.k.mallick(a)intel.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Linus Torvalds <torvalds(a)linux-foundation.org>
Cc: Jason Baron <jbaron(a)akamai.com>
Cc: Paolo Bonzini <pbonzini(a)redhat.com>
Cc: Alok Kataria <akataria(a)vmware.com>
Cc: Arjan Van De Ven <arjan.van.de.ven(a)intel.com>
Cc: David Woodhouse <dwmw2(a)infradead.org>
Cc: Dan Williams <dan.j.williams(a)intel.com>
Link: https://lkml.kernel.org/r/20180131041333.2x6blhxirc2kclrq@treble
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
Documentation/admin-guide/kernel-parameters.txt | 2 --
arch/x86/kernel/alternative.c | 14 --------------
2 files changed, 16 deletions(-)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2742,8 +2742,6 @@
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
- noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops
-
noreplace-smp [X86-32,SMP] Don't replace SMP instructions
with UP alternatives
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -46,17 +46,6 @@ static int __init setup_noreplace_smp(ch
}
__setup("noreplace-smp", setup_noreplace_smp);
-#ifdef CONFIG_PARAVIRT
-static int __initdata_or_module noreplace_paravirt = 0;
-
-static int __init setup_noreplace_paravirt(char *str)
-{
- noreplace_paravirt = 1;
- return 1;
-}
-__setup("noreplace-paravirt", setup_noreplace_paravirt);
-#endif
-
#define DPRINTK(fmt, args...) \
do { \
if (debug_alternative) \
@@ -599,9 +588,6 @@ void __init_or_module apply_paravirt(str
struct paravirt_patch_site *p;
char insnbuf[MAX_PATCH_LEN];
- if (noreplace_paravirt)
- return;
-
for (p = start; p < end; p++) {
unsigned int used;
Patches currently in stable-queue which might be from jpoimboe(a)redhat.com are
queue-4.15/objtool_Add_support_for_alternatives_at_the_end_of_a_section.patch
queue-4.15/x86paravirt_Remove_noreplace-paravirt_cmdline_option.patch
queue-4.15/KVM_VMX_Make_indirect_call_speculation_safe.patch
queue-4.15/x86alternative_Print_unadorned_pointers.patch
queue-4.15/x86bugs_Drop_one_mitigation_from_dmesg.patch
queue-4.15/x86nospec_Fix_header_guards_names.patch
queue-4.15/KVM_x86_Make_indirect_calls_in_emulator_speculation_safe.patch
queue-4.15/objtool_Warn_on_stripped_section_symbol.patch
queue-4.15/objtool_Improve_retpoline_alternative_handling.patch
This is a note to let you know that I've just added the patch titled
x86/pti: Mark constant arrays as __initconst
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86pti_Mark_constant_arrays_as___initconst.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/pti: Mark constant arrays as __initconst
From: Arnd Bergmann arnd(a)arndb.de
Date: Fri Feb 2 22:39:23 2018 +0100
From: Arnd Bergmann arnd(a)arndb.de
commit 4bf5d56d429cbc96c23d809a08f63cd29e1a702e
I'm seeing build failures from the two newly introduced arrays that
are marked 'const' and '__initdata', which are mutually exclusive:
arch/x86/kernel/cpu/common.c:882:43: error: 'cpu_no_speculation' causes a section type conflict with 'e820_table_firmware_init'
arch/x86/kernel/cpu/common.c:895:43: error: 'cpu_no_meltdown' causes a section type conflict with 'e820_table_firmware_init'
The correct annotation is __initconst.
Fixes: fec9434a12f3 ("x86/pti: Do not enable PTI on CPUs which are not vulnerable to Meltdown")
Signed-off-by: Arnd Bergmann <arnd(a)arndb.de>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Ricardo Neri <ricardo.neri-calderon(a)linux.intel.com>
Cc: Andy Lutomirski <luto(a)kernel.org>
Cc: Borislav Petkov <bp(a)suse.de>
Cc: Thomas Garnier <thgarnie(a)google.com>
Cc: David Woodhouse <dwmw(a)amazon.co.uk>
Link: https://lkml.kernel.org/r/20180202213959.611210-1-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/kernel/cpu/common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -900,7 +900,7 @@ static void identify_cpu_without_cpuid(s
#endif
}
-static const __initdata struct x86_cpu_id cpu_no_speculation[] = {
+static const __initconst struct x86_cpu_id cpu_no_speculation[] = {
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW, X86_FEATURE_ANY },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW, X86_FEATURE_ANY },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT, X86_FEATURE_ANY },
@@ -913,7 +913,7 @@ static const __initdata struct x86_cpu_i
{}
};
-static const __initdata struct x86_cpu_id cpu_no_meltdown[] = {
+static const __initconst struct x86_cpu_id cpu_no_meltdown[] = {
{ X86_VENDOR_AMD },
{}
};
Patches currently in stable-queue which might be from arnd(a)arndb.de are
queue-4.15/x86pti_Mark_constant_arrays_as___initconst.patch
queue-4.15/auxdisplay-img-ascii-lcd-add-missing-module_description-author-license.patch
This is a note to let you know that I've just added the patch titled
x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAP
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum…
The filename of the patch is:
x86mm_Fix_overlap_of_i386_CPU_ENTRY_AREA_with_FIX_BTMAP.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable(a)vger.kernel.org> know about it.
Subject: x86/mm: Fix overlap of i386 CPU_ENTRY_AREA with FIX_BTMAP
From: William Grant william.grant(a)canonical.com
Date: Tue Jan 30 22:22:55 2018 +1100
From: William Grant william.grant(a)canonical.com
commit 55f49fcb879fbeebf2a8c1ac7c9e6d90df55f798
Since commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the
fixmap"), i386's CPU_ENTRY_AREA has been mapped to the memory area just
below FIXADDR_START. But already immediately before FIXADDR_START is the
FIX_BTMAP area, which means that early_ioremap can collide with the entry
area.
It's especially bad on PAE where FIX_BTMAP_BEGIN gets aligned to exactly
match CPU_ENTRY_AREA_BASE, so the first early_ioremap slot clobbers the
IDT and causes interrupts during early boot to reset the system.
The overlap wasn't a problem before the CPU entry area was introduced,
as the fixmap has classically been preceded by the pkmap or vmalloc
areas, neither of which is used until early_ioremap is out of the
picture.
Relocate CPU_ENTRY_AREA to below FIX_BTMAP, not just below the permanent
fixmap area.
Fixes: commit 92a0f81d8957 ("x86/cpu_entry_area: Move it out of the fixmap")
Signed-off-by: William Grant <william.grant(a)canonical.com>
Signed-off-by: Thomas Gleixner <tglx(a)linutronix.de>
Cc: stable(a)vger.kernel.org
Link: https://lkml.kernel.org/r/7041d181-a019-e8b9-4e4e-48215f841e2c@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
arch/x86/include/asm/fixmap.h | 6 ++++--
arch/x86/include/asm/pgtable_32_types.h | 5 +++--
2 files changed, 7 insertions(+), 4 deletions(-)
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -137,8 +137,10 @@ enum fixed_addresses {
extern void reserve_top_address(unsigned long reserve);
-#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
-#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+#define FIXADDR_SIZE (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
+#define FIXADDR_TOT_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_TOT_START (FIXADDR_TOP - FIXADDR_TOT_SIZE)
extern int fixmaps_set;
--- a/arch/x86/include/asm/pgtable_32_types.h
+++ b/arch/x86/include/asm/pgtable_32_types.h
@@ -44,8 +44,9 @@ extern bool __vmalloc_start_set; /* set
*/
#define CPU_ENTRY_AREA_PAGES (NR_CPUS * 40)
-#define CPU_ENTRY_AREA_BASE \
- ((FIXADDR_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) & PMD_MASK)
+#define CPU_ENTRY_AREA_BASE \
+ ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1)) \
+ & PMD_MASK)
#define PKMAP_BASE \
((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)
Patches currently in stable-queue which might be from william.grant(a)canonical.com are
queue-4.15/x86mm_Fix_overlap_of_i386_CPU_ENTRY_AREA_with_FIX_BTMAP.patch