Subject: Patch "[PATCH 22/27] powerpc/speculation: Support 'mitigations=' cmdline" has been added to the 5.1-stable tree

From: <[email-masked]>
Date: Tue, 14 May 2019 19:06:20 +0200

This is a note to let you know that I've just added the patch titled

    [PATCH 22/27] powerpc/speculation: Support 'mitigations=' cmdline

to the 5.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     0022-powerpc-speculation-Support-mitigations-cmdline-opti.patch
and it can be found in the queue-5.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email-masked]> know about it.

>From b7344dd66dc6a99ecabeb0ab059334eba128da83 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <[email-masked]>
Date: Fri, 12 Apr 2019 15:39:30 -0500
Subject: [PATCH 22/27] powerpc/speculation: Support 'mitigations=' cmdline
 option

commit 782e69efb3dfed6e8360bc612e8c7827a901a8f9 upstream

Configure powerpc CPU runtime speculation bug mitigations in accordance
with the 'mitigations=' cmdline option.  This affects Meltdown, Spectre
v1, Spectre v2, and Speculative Store Bypass.

The default behavior is unchanged.

Signed-off-by: Josh Poimboeuf <[email-masked]>
Signed-off-by: Thomas Gleixner <[email-masked]>
Tested-by: Jiri Kosina <[email-masked]> (on x86)
Reviewed-by: Jiri Kosina <[email-masked]>
Cc: Borislav Petkov <[email-masked]>
Cc: "H . Peter Anvin" <[email-masked]>
Cc: Andy Lutomirski <[email-masked]>
Cc: Peter Zijlstra <[email-masked]>
Cc: Jiri Kosina <[email-masked]>
Cc: Waiman Long <[email-masked]>
Cc: Andrea Arcangeli <[email-masked]>
Cc: Jon Masters <[email-masked]>
Cc: Benjamin Herrenschmidt <[email-masked]>
Cc: Paul Mackerras <[email-masked]>
Cc: Michael Ellerman <[email-masked]>
Cc: [email-masked]
Cc: Martin Schwidefsky <[email-masked]>
Cc: Heiko Carstens <[email-masked]>
Cc: [email-masked]
Cc: Catalin Marinas <[email-masked]>
Cc: Will Deacon <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Cc: Greg Kroah-Hartman <[email-masked]>
Cc: Tyler Hicks <[email-masked]>
Cc: Linus Torvalds <[email-masked]>
Cc: Randy Dunlap <[email-masked]>
Cc: Steven Price <[email-masked]>
Cc: Phil Auld <[email-masked]>
Link: https://lkml.kernel.org/r/[email-masked]
Signed-off-by: Greg Kroah-Hartman <[email-masked]>
---
 Documentation/admin-guide/kernel-parameters.txt | 9 +++++----
 arch/powerpc/kernel/security.c                  | 6 +++---
 arch/powerpc/kernel/setup_64.c                  | 2 +-
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 4392a66bfa3d..3294030d7f57 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2571,7 +2571,7 @@
 			http://repo.or.cz/w/linux-2.6/mini2440.git
 
 	mitigations=
-			[X86] Control optional mitigations for CPU
+			[X86,PPC] Control optional mitigations for CPU
 			vulnerabilities.  This is a set of curated,
 			arch-independent options, each of which is an
 			aggregation of existing arch-specific options.
@@ -2580,10 +2580,11 @@
 				Disable all optional CPU mitigations.  This
 				improves system performance, but it may also
 				expose users to several CPU vulnerabilities.
-				Equivalent to: nopti [X86]
-					       nospectre_v2 [X86]
+				Equivalent to: nopti [X86,PPC]
+					       nospectre_v1 [PPC]
+					       nospectre_v2 [X86,PPC]
 					       spectre_v2_user=off [X86]
-					       spec_store_bypass_disable=off [X86]
+					       spec_store_bypass_disable=off [X86,PPC]
 					       l1tf=off [X86]
 
 			auto (default)
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index b33bafb8fcea..70568ccbd9fd 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -57,7 +57,7 @@ void setup_barrier_nospec(void)
 	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
 		 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
 
-	if (!no_nospec)
+	if (!no_nospec && !cpu_mitigations_off())
 		enable_barrier_nospec(enable);
 }
 
@@ -116,7 +116,7 @@ static int __init handle_nospectre_v2(char *p)
 early_param("nospectre_v2", handle_nospectre_v2);
 void setup_spectre_v2(void)
 {
-	if (no_spectrev2)
+	if (no_spectrev2 || cpu_mitigations_off())
 		do_btb_flush_fixups();
 	else
 		btb_flush_enabled = true;
@@ -300,7 +300,7 @@ void setup_stf_barrier(void)
 
 	stf_enabled_flush_types = type;
 
-	if (!no_stf_barrier)
+	if (!no_stf_barrier && !cpu_mitigations_off())
 		stf_barrier_enable(enable);
 }
 
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index ba404dd9ce1d..4f49e1a3594c 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -932,7 +932,7 @@ void setup_rfi_flush(enum l1d_flush_type types, bool enable)
 
 	enabled_flush_types = types;
 
-	if (!no_rfi_flush)
+	if (!no_rfi_flush && !cpu_mitigations_off())
 		rfi_flush_enable(enable);
 }
 
-- 
2.21.0

Patches currently in stable-queue which might be from [email-masked] are

queue-5.1/0019-x86-speculation-mds-Print-SMT-vulnerable-on-MSBDS-wi.patch
queue-5.1/0016-x86-speculation-Move-arch_smt_update-call-to-after-m.patch
queue-5.1/0024-x86-speculation-mds-Add-mitigations-support-for-MDS.patch
queue-5.1/0021-x86-speculation-Support-mitigations-cmdline-option.patch
queue-5.1/0022-powerpc-speculation-Support-mitigations-cmdline-opti.patch
queue-5.1/0020-cpu-speculation-Add-mitigations-cmdline-option.patch
queue-5.1/0023-s390-speculation-Support-mitigations-cmdline-option.patch
queue-5.1/0015-x86-speculation-mds-Add-mds-full-nosmt-cmdline-optio.patch
queue-5.1/0027-x86-speculation-mds-Fix-documentation-typo.patch
queue-5.1/0017-x86-speculation-mds-Add-SMT-warning-message.patch
queue-5.1/0018-x86-speculation-mds-Fix-comment.patch

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