From e10cc8715d180509a367d3ab25d40e4a1612cb2f Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Date: Thu, 9 Jul 2020 08:59:37 +0530
Subject: [PATCH] powerpc/book3s64/kuep: Add MMU_FTR_KUEP

References: jsc#SLE-16556 bsc#1078248 FATE#322447
Patch-mainline: v5.9-rc1
Git-commit: e10cc8715d180509a367d3ab25d40e4a1612cb2f

This will be used to enable/disable Kernel Userspace Execution
Prevention (KUEP).

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200709032946.881753-15-aneesh.kumar@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/include/asm/mmu.h           | 9 +++++++++
 arch/powerpc/mm/book3s64/radix_pgtable.c | 4 +++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 17cbaf132631..255a1837e9f7 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -28,6 +28,11 @@
  * Individual features below.
  */
 
+/*
+ * Support for KUEP feature.
+ */
+#define MMU_FTR_KUEP			ASM_CONST(0x00000400)
+
 /*
  * Support for memory protection keys.
  */
@@ -189,6 +194,10 @@ enum {
 #ifdef CONFIG_PPC_MEM_KEYS
 	MMU_FTR_PKEY |
 #endif
+#ifdef CONFIG_PPC_KUEP
+	MMU_FTR_KUEP |
+#endif /* CONFIG_PPC_KUAP */
+
 		0,
 };
 
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index c5bf2ef73c36..3536675dd61e 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -593,8 +593,10 @@ void setup_kuep(bool disabled)
 	if (disabled || !early_radix_enabled())
 		return;
 
-	if (smp_processor_id() == boot_cpuid)
+	if (smp_processor_id() == boot_cpuid) {
 		pr_info("Activating Kernel Userspace Execution Prevention\n");
+		cur_cpu_spec->mmu_features |= MMU_FTR_KUEP;
+	}
 
 	/*
 	 * Radix always uses key0 of the IAMR to determine if an access is
-- 
2.26.2