From cf175dc315f90185128fb061dc05b6fbb211aa2f Mon Sep 17 00:00:00 2001
From: Diana Craciun <diana.craciun@nxp.com>
Date: Sat, 28 Jul 2018 09:06:32 +1000
Subject: [PATCH] powerpc/64: Disable the speculation barrier from the command
 line

References: bsc#1131107
Patch-mainline: v4.19-rc1
Git-commit: cf175dc315f90185128fb061dc05b6fbb211aa2f

The speculation barrier can be disabled from the command line
with the parameter: "nospectre_v1".

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/kernel/security.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 4cb8f1f7b593..79f9397998ed 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -16,6 +16,7 @@
 unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
 
 bool barrier_nospec_enabled;
+static bool no_nospec;
 
 static void enable_barrier_nospec(bool enable)
 {
@@ -42,9 +43,18 @@ void setup_barrier_nospec(void)
 	enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
 		 security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
 
-	enable_barrier_nospec(enable);
+	if (!no_nospec)
+		enable_barrier_nospec(enable);
 }
 
+static int __init handle_nospectre_v1(char *p)
+{
+	no_nospec = true;
+
+	return 0;
+}
+early_param("nospectre_v1", handle_nospectre_v1);
+
 #ifdef CONFIG_DEBUG_FS
 static int barrier_nospec_set(void *data, u64 val)
 {
-- 
2.20.1