This patch defines a function to detect the secure boot state of a
PowerNV system.

The PPC_SECURE_BOOT config represents the base enablement of secure boot
for powerpc.

Signed-off-by: Nayna Jain <na...@linux.ibm.com>
---
 arch/powerpc/Kconfig                   | 10 +++++++++
 arch/powerpc/include/asm/secure_boot.h | 23 ++++++++++++++++++++
 arch/powerpc/kernel/Makefile           |  2 ++
 arch/powerpc/kernel/secure_boot.c      | 30 ++++++++++++++++++++++++++
 4 files changed, 65 insertions(+)
 create mode 100644 arch/powerpc/include/asm/secure_boot.h
 create mode 100644 arch/powerpc/kernel/secure_boot.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3e56c9c2f16e..56ea0019b616 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -934,6 +934,16 @@ config PPC_MEM_KEYS
 
          If unsure, say y.
 
+config PPC_SECURE_BOOT
+       prompt "Enable secure boot support"
+       bool
+       depends on PPC_POWERNV
+       help
+         Systems with firmware secure boot enabled need to define security
+         policies to extend secure boot to the OS. This config allows a user
+         to enable OS secure boot on systems that have firmware support for
+         it. If in doubt say N.
+
 endmenu
 
 config ISA_DMA_API
diff --git a/arch/powerpc/include/asm/secure_boot.h 
b/arch/powerpc/include/asm/secure_boot.h
new file mode 100644
index 000000000000..07d0fe0ca81f
--- /dev/null
+++ b/arch/powerpc/include/asm/secure_boot.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Secure boot definitions
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+#ifndef _ASM_POWER_SECURE_BOOT_H
+#define _ASM_POWER_SECURE_BOOT_H
+
+#ifdef CONFIG_PPC_SECURE_BOOT
+
+bool is_ppc_secureboot_enabled(void);
+
+#else
+
+static inline bool is_ppc_secureboot_enabled(void)
+{
+       return false;
+}
+
+#endif
+#endif
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index a7ca8fe62368..e2a54fa240ac 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -161,6 +161,8 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
 obj-y                          += ucall.o
 endif
 
+obj-$(CONFIG_PPC_SECURE_BOOT)  += secure_boot.o
+
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
 KCOV_INSTRUMENT_prom_init.o := n
diff --git a/arch/powerpc/kernel/secure_boot.c 
b/arch/powerpc/kernel/secure_boot.c
new file mode 100644
index 000000000000..99bba7915629
--- /dev/null
+++ b/arch/powerpc/kernel/secure_boot.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+#include <linux/types.h>
+#include <linux/of.h>
+#include <asm/secure_boot.h>
+
+bool is_ppc_secureboot_enabled(void)
+{
+       struct device_node *node;
+       bool enabled = false;
+
+       node = of_find_compatible_node(NULL, NULL, "ibm,secvar-v1");
+       if (!of_device_is_available(node)) {
+               pr_err("Cannot find secure variable node in device tree; 
failing to secure state\n");
+               goto out;
+       }
+
+       /*
+        * secureboot is enabled if os-secure-enforcing property exists,
+        * else disabled.
+        */
+       enabled = of_property_read_bool(node, "os-secure-enforcing");
+
+out:
+       pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
+       return enabled;
+}
-- 
2.20.1

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