[PATCH v2 1/4] powerpc/powernv: Add OPAL API interface to access secure variable

Nayna Jain nayna at linux.ibm.com
Thu Aug 22 01:08:20 AEST 2019


The X.509 certificates trusted by the platform and required to secure boot
the OS kernel are wrapped in secure variables, which are controlled by
OPAL.

This patch adds firmware/kernel interface to read and write OPAL secure
variables based on the unique key.

This support can be enabled using CONFIG_OPAL_SECVAR.

Signed-off-by: Claudio Carvalho <cclaudio at linux.ibm.com>
Signed-off-by: Nayna Jain <nayna at linux.ibm.com>
---
 arch/powerpc/include/asm/opal-api.h          |   5 +-
 arch/powerpc/include/asm/opal.h              |   6 ++
 arch/powerpc/include/asm/secvar.h            |  55 ++++++++++
 arch/powerpc/kernel/Makefile                 |   2 +-
 arch/powerpc/kernel/secvar-ops.c             |  25 +++++
 arch/powerpc/platforms/powernv/Kconfig       |   6 ++
 arch/powerpc/platforms/powernv/Makefile      |   1 +
 arch/powerpc/platforms/powernv/opal-call.c   |   3 +
 arch/powerpc/platforms/powernv/opal-secvar.c | 102 +++++++++++++++++++
 arch/powerpc/platforms/powernv/opal.c        |   5 +
 10 files changed, 208 insertions(+), 2 deletions(-)
 create mode 100644 arch/powerpc/include/asm/secvar.h
 create mode 100644 arch/powerpc/kernel/secvar-ops.c
 create mode 100644 arch/powerpc/platforms/powernv/opal-secvar.c

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 383242eb0dea..b238b4f26c5b 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -208,7 +208,10 @@
 #define OPAL_HANDLE_HMI2			166
 #define	OPAL_NX_COPROC_INIT			167
 #define OPAL_XIVE_GET_VP_STATE			170
-#define OPAL_LAST				170
+#define OPAL_SECVAR_GET                         173
+#define OPAL_SECVAR_GET_NEXT                    174
+#define OPAL_SECVAR_ENQUEUE_UPDATE              175
+#define OPAL_LAST                               175
 
 #define QUIESCE_HOLD			1 /* Spin all calls at entry */
 #define QUIESCE_REJECT			2 /* Fail all calls with OPAL_BUSY */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 57bd029c715e..247adec2375f 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -388,6 +388,12 @@ void opal_powercap_init(void);
 void opal_psr_init(void);
 void opal_sensor_groups_init(void);
 
+extern int opal_secvar_get(uint64_t k_key, uint64_t k_key_len,
+			   uint64_t k_data, uint64_t k_data_size);
+extern int opal_secvar_get_next(uint64_t k_key, uint64_t k_key_len,
+				uint64_t k_key_size);
+extern int opal_secvar_enqueue_update(uint64_t k_key, uint64_t k_key_len,
+				      uint64_t k_data, uint64_t k_data_size);
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_OPAL_H */
diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
new file mode 100644
index 000000000000..645654456265
--- /dev/null
+++ b/arch/powerpc/include/asm/secvar.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * PowerPC secure variable operations.
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain <nayna at linux.ibm.com>
+ *
+ */
+#ifndef SECVAR_OPS_H
+#define SECVAR_OPS_H
+
+#include<linux/types.h>
+#include<linux/errno.h>
+
+struct secvar_operations {
+	int (*get_variable)(const char *key, unsigned long key_len, u8 *data,
+			    unsigned long *data_size);
+	int (*get_next_variable)(const char *key, unsigned long *key_len,
+				 unsigned long keysize);
+	int (*set_variable)(const char *key, unsigned long key_len, u8 *data,
+			    unsigned long data_size);
+};
+
+#ifdef CONFIG_PPC_SECURE_BOOT
+
+extern void set_secvar_ops(struct secvar_operations *ops);
+extern struct secvar_operations *get_secvar_ops(void);
+
+#else
+
+static inline void set_secvar_ops(struct secvar_operations *ops)
+{
+}
+
+static inline struct secvar_operations *get_secvar_ops(void)
+{
+	return NULL;
+}
+
+#endif
+
+#ifdef CONFIG_OPAL_SECVAR
+
+extern int secvar_init(void);
+
+#else
+
+static inline int secvar_init(void)
+{
+	return -EINVAL;
+}
+
+#endif
+
+#endif
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 520b1c814197..9041563f1c74 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -157,7 +157,7 @@ endif
 obj-$(CONFIG_EPAPR_PARAVIRT)	+= epapr_paravirt.o epapr_hcalls.o
 obj-$(CONFIG_KVM_GUEST)		+= kvm.o kvm_emul.o
 
-obj-$(CONFIG_PPC_SECURE_BOOT)	+= secboot.o ima_arch.o
+obj-$(CONFIG_PPC_SECURE_BOOT)	+= secboot.o ima_arch.o secvar-ops.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/secvar-ops.c b/arch/powerpc/kernel/secvar-ops.c
new file mode 100644
index 000000000000..198222499848
--- /dev/null
+++ b/arch/powerpc/kernel/secvar-ops.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain <nayna at linux.ibm.com>
+ *
+ * secvar-ops.c
+ *      - initialize secvar operations for PowerPC Secureboot
+ */
+
+#include<stddef.h>
+#include<asm/secvar.h>
+
+static struct secvar_operations *secvars_ops;
+
+void set_secvar_ops(struct secvar_operations *ops)
+{
+	if (!ops)
+		secvars_ops = NULL;
+	secvars_ops = ops;
+}
+
+struct secvar_operations *get_secvar_ops(void)
+{
+	return secvars_ops;
+}
diff --git a/arch/powerpc/platforms/powernv/Kconfig b/arch/powerpc/platforms/powernv/Kconfig
index 850eee860cf2..65b060539b5c 100644
--- a/arch/powerpc/platforms/powernv/Kconfig
+++ b/arch/powerpc/platforms/powernv/Kconfig
@@ -47,3 +47,9 @@ config PPC_VAS
 	  VAS adapters are found in POWER9 based systems.
 
 	  If unsure, say N.
+
+config OPAL_SECVAR
+	bool "OPAL Secure Variables"
+	depends on PPC_POWERNV
+	help
+	  This enables the kernel to access OPAL secure variables.
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index da2e99efbd04..6651c742e530 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -16,3 +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
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index 29ca523c1c79..93106e867924 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -287,3 +287,6 @@ OPAL_CALL(opal_pci_set_pbcq_tunnel_bar,		OPAL_PCI_SET_PBCQ_TUNNEL_BAR);
 OPAL_CALL(opal_sensor_read_u64,			OPAL_SENSOR_READ_U64);
 OPAL_CALL(opal_sensor_group_enable,		OPAL_SENSOR_GROUP_ENABLE);
 OPAL_CALL(opal_nx_coproc_init,			OPAL_NX_COPROC_INIT);
+OPAL_CALL(opal_secvar_get,                     OPAL_SECVAR_GET);
+OPAL_CALL(opal_secvar_get_next,                 OPAL_SECVAR_GET_NEXT);
+OPAL_CALL(opal_secvar_enqueue_update,           OPAL_SECVAR_ENQUEUE_UPDATE);
diff --git a/arch/powerpc/platforms/powernv/opal-secvar.c b/arch/powerpc/platforms/powernv/opal-secvar.c
new file mode 100644
index 000000000000..b0f97cea7675
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-secvar.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PowerNV code for secure variables
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Claudio Carvalho <cclaudio at linux.ibm.com>
+ *
+ * APIs to access secure variables managed by OPAL.
+ *
+ */
+
+#define pr_fmt(fmt) "secvar: "fmt
+
+#include <linux/types.h>
+#include <asm/opal.h>
+#include <asm/secvar.h>
+
+static bool is_opal_secvar_supported(void)
+{
+	static bool opal_secvar_supported;
+	static bool initialized;
+
+	if (initialized)
+		return opal_secvar_supported;
+
+	if (!opal_check_token(OPAL_SECVAR_GET)
+			|| !opal_check_token(OPAL_SECVAR_GET_NEXT)
+			|| !opal_check_token(OPAL_SECVAR_ENQUEUE_UPDATE)) {
+		pr_err("OPAL doesn't support secure variables\n");
+		opal_secvar_supported = false;
+	} else {
+		opal_secvar_supported = true;
+	}
+
+	initialized = true;
+
+	return opal_secvar_supported;
+}
+
+static int opal_get_variable(const char *key, unsigned long ksize,
+			     u8 *data, unsigned long *dsize)
+{
+	int rc;
+
+	if (!is_opal_secvar_supported())
+		return OPAL_UNSUPPORTED;
+
+	if (dsize)
+		*dsize = cpu_to_be64(*dsize);
+
+	rc = opal_secvar_get(__pa(key), ksize,
+			__pa(data), __pa(dsize));
+
+	if (dsize)
+		*dsize = be64_to_cpu(*dsize);
+
+	return rc;
+}
+
+static int opal_get_next_variable(const char *key, unsigned long *keylen,
+				  unsigned long keysize)
+{
+	int rc;
+
+	if (!is_opal_secvar_supported())
+		return OPAL_UNSUPPORTED;
+
+	if (keylen)
+		*keylen = cpu_to_be64(*keylen);
+
+	rc = opal_secvar_get_next(__pa(key), __pa(keylen), keysize);
+
+	if (keylen)
+		*keylen = be64_to_cpu(*keylen);
+
+	return rc;
+}
+
+static int opal_set_variable(const char *key, unsigned long ksize, u8 *data,
+			     unsigned long dsize)
+{
+	int rc;
+
+	if (!is_opal_secvar_supported())
+		return OPAL_UNSUPPORTED;
+
+	rc = opal_secvar_enqueue_update(__pa(key), ksize, __pa(data), dsize);
+
+	return rc;
+}
+
+static struct secvar_operations secvar_ops = {
+	.get_variable = opal_get_variable,
+	.get_next_variable = opal_get_next_variable,
+	.set_variable = opal_set_variable,
+};
+
+int secvar_init(void)
+{
+	set_secvar_ops(&secvar_ops);
+	return 0;
+}
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index aba443be7daa..ffe6f1cf0830 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -32,6 +32,8 @@
 #include <asm/mce.h>
 #include <asm/imc-pmu.h>
 #include <asm/bug.h>
+#include <asm/secvar.h>
+#include <asm/secboot.h>
 
 #include "powernv.h"
 
@@ -988,6 +990,9 @@ static int __init opal_init(void)
 	/* Initialise OPAL Power control interface */
 	opal_power_control_init();
 
+	if (is_powerpc_secvar_supported())
+		secvar_init();
+
 	return 0;
 }
 machine_subsys_initcall(powernv, opal_init);
-- 
2.20.1



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