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Subject[PATCH v4 2/3] powerpc/powernv: detect the secure boot mode of the system
Date
PowerNV secure boot defines different IMA policies based on the secure
boot state of the system.

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

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
arch/powerpc/include/asm/secboot.h | 21 ++++++++
arch/powerpc/platforms/powernv/Makefile | 2 +-
arch/powerpc/platforms/powernv/secboot.c | 61 ++++++++++++++++++++++++
3 files changed, 83 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/include/asm/secboot.h
create mode 100644 arch/powerpc/platforms/powernv/secboot.c

diff --git a/arch/powerpc/include/asm/secboot.h b/arch/powerpc/include/asm/secboot.h
new file mode 100644
index 000000000000..1904fb4a3352
--- /dev/null
+++ b/arch/powerpc/include/asm/secboot.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * PowerPC secure boot definitions
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain <nayna@linux.ibm.com>
+ *
+ */
+#ifndef POWERPC_SECBOOT_H
+#define POWERPC_SECBOOT_H
+
+#if defined(CONFIG_OPAL_SECVAR)
+extern bool get_powerpc_sb_mode(void);
+#else
+static inline bool get_powerpc_sb_mode(void)
+{
+ return false;
+}
+#endif
+
+#endif
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index 6651c742e530..6f4af607a915 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -16,4 +16,4 @@ obj-$(CONFIG_PERF_EVENTS) += opal-imc.o
obj-$(CONFIG_PPC_MEMTRACE) += memtrace.o
obj-$(CONFIG_PPC_VAS) += vas.o vas-window.o vas-debug.o
obj-$(CONFIG_OCXL_BASE) += ocxl.o
-obj-$(CONFIG_OPAL_SECVAR) += opal-secvar.o
+obj-$(CONFIG_OPAL_SECVAR) += opal-secvar.o secboot.o
diff --git a/arch/powerpc/platforms/powernv/secboot.c b/arch/powerpc/platforms/powernv/secboot.c
new file mode 100644
index 000000000000..9199e520ebed
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/secboot.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain <nayna@linux.ibm.com>
+ *
+ * secboot.c
+ * - util function to get powerpc secboot state
+ */
+#include <linux/uuid.h>
+#include <asm/opal.h>
+#include <asm/secboot.h>
+#include <asm/opal-secvar.h>
+
+bool get_powerpc_sb_mode(void)
+{
+ u8 secure_boot_name[] = "SecureBoot";
+ u8 setup_mode_name[] = "SetupMode";
+ u8 secboot, setupmode;
+ unsigned long size = sizeof(secboot);
+ int status;
+ unsigned long version;
+
+ status = opal_variable_version(&version);
+ if ((status != OPAL_SUCCESS) || (version != BACKEND_TC_COMPAT_V1)) {
+ pr_info("secboot: error retrieving compatible backend\n");
+ return false;
+ }
+
+ status = opal_get_variable(secure_boot_name, sizeof(secure_boot_name),
+ NULL, NULL, &secboot, &size);
+
+ /*
+ * For now assume all failures reading the SecureBoot variable implies
+ * secure boot is not enabled. Later differentiate failure types.
+ */
+ if (status != OPAL_SUCCESS) {
+ secboot = 0;
+ setupmode = 0;
+ goto out;
+ }
+
+ size = sizeof(setupmode);
+ status = opal_get_variable(setup_mode_name, sizeof(setup_mode_name),
+ NULL, NULL, &setupmode, &size);
+
+ /*
+ * Failure to read the SetupMode variable does not prevent
+ * secure boot mode
+ */
+ if (status != OPAL_SUCCESS)
+ setupmode = 0;
+
+out:
+ if ((secboot == 0) || (setupmode == 1)) {
+ pr_info("secboot: secureboot mode disabled\n");
+ return false;
+ }
+
+ pr_info("secboot: secureboot mode enabled\n");
+ return true;
+}
--
2.20.1
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