powerpc: initial pkey plumbing

Basic  plumbing  to   initialize  the   pkey  system.
Nothing is enabled yet. A later patch will enable it
once all the infrastructure is in place.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
[mpe: Rework copyrights to use SPDX tags]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

3 files changed, 31 insertions, 0 deletions

diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 8d271bfe2d94..f06f3577d8d1 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -44,3 +44,4 @@ obj-$(CONFIG_PPC_COPRO_BASE)	+= copro_fault.o
 obj-$(CONFIG_SPAPR_TCE_IOMMU)	+= mmu_context_iommu.o
 obj-$(CONFIG_PPC_PTDUMP)	+= dump_linuxpagetables.o
 obj-$(CONFIG_PPC_HTDUMP)	+= dump_hashpagetable.o
+obj-$(CONFIG_PPC_MEM_KEYS)	+= pkeys.o
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 64e704eefad1..8cd31ea9b243 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -36,6 +36,7 @@
 #include <linux/memblock.h>
 #include <linux/context_tracking.h>
 #include <linux/libfdt.h>
+#include <linux/pkeys.h>
 
 #include <asm/debugfs.h>
 #include <asm/processor.h>
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
new file mode 100644
index 000000000000..a11afba584b9
--- /dev/null
+++ b/arch/powerpc/mm/pkeys.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PowerPC Memory Protection Keys management
+ *
+ * Copyright 2017, Ram Pai, IBM Corporation.
+ */
+
+#include <linux/pkeys.h>
+
+DEFINE_STATIC_KEY_TRUE(pkey_disabled);
+bool pkey_execute_disable_supported;
+
+int pkey_initialize(void)
+{
+	/*
+	 * Disable the pkey system till everything is in place. A subsequent
+	 * patch will enable it.
+	 */
+	static_branch_enable(&pkey_disabled);
+
+	/*
+	 * Disable execute_disable support for now. A subsequent patch will
+	 * enable it.
+	 */
+	pkey_execute_disable_supported = false;
+	return 0;
+}
+
+arch_initcall(pkey_initialize);