From 030905920f32e91a52794937f67434ac0b3ea41a Mon Sep 17 00:00:00 2001
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Date: Wed, 6 Oct 2021 01:55:24 +0530
Subject: [PATCH] powerpc/security: Add a helper to query stf_barrier type

References: bsc#1188983 CVE-2021-34556 bsc#1188985 CVE-2021-35477
Patch-mainline: v5.15-rc5
Git-commit: 030905920f32e91a52794937f67434ac0b3ea41a

Add a helper to return the stf_barrier type for the current processor.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3bd5d7f96ea1547991ac2ce3137dc2b220bae285.1633464148.git.naveen.n.rao@linux.vnet.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/include/asm/security_features.h | 5 +++++
 arch/powerpc/kernel/security.c               | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h
index 792eefaf230b..27574f218b37 100644
--- a/arch/powerpc/include/asm/security_features.h
+++ b/arch/powerpc/include/asm/security_features.h
@@ -39,6 +39,11 @@ static inline bool security_ftr_enabled(u64 feature)
 	return !!(powerpc_security_features & feature);
 }
 
+#ifdef CONFIG_PPC_BOOK3S_64
+enum stf_barrier_type stf_barrier_type_get(void);
+#else
+static inline enum stf_barrier_type stf_barrier_type_get(void) { return STF_BARRIER_NONE; }
+#endif
 
 // Features indicating support for Spectre/Meltdown mitigations
 
diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
index 1a998490fe60..15fb5ea1b9ea 100644
--- a/arch/powerpc/kernel/security.c
+++ b/arch/powerpc/kernel/security.c
@@ -263,6 +263,11 @@ static int __init handle_no_stf_barrier(char *p)
 
 early_param("no_stf_barrier", handle_no_stf_barrier);
 
+enum stf_barrier_type stf_barrier_type_get(void)
+{
+	return stf_enabled_flush_types;
+}
+
 /* This is the generic flag used by other architectures */
 static int __init handle_ssbd(char *p)
 {
-- 
2.31.1