Merge branch 'topic/secureboot' into next

Merge the secureboot support, as well as the IMA changes needed to
support it.

From Nayna's cover letter:
  In order to verify the OS kernel on PowerNV systems, secure boot
  requires X.509 certificates trusted by the platform. These are
  stored in secure variables controlled by OPAL, called OPAL secure
  variables. In order to enable users to manage the keys, the secure
  variables need to be exposed to userspace.

  OPAL provides the runtime services for the kernel to be able to
  access the secure variables. This patchset defines the kernel
  interface for the OPAL APIs. These APIs are used by the hooks, which
  load these variables to the keyring and expose them to the userspace
  for reading/writing.

  Overall, this patchset adds the following support:
    * expose secure variables to the kernel via OPAL Runtime API interface
    * expose secure variables to the userspace via kernel sysfs interface
    * load kernel verification and revocation keys to .platform and
      .blacklist keyring respectively.

  The secure variables can be read/written using simple linux
  utilities cat/hexdump.

  For example:
  Path to the secure variables is: /sys/firmware/secvar/vars

    Each secure variable is listed as directory.
    $ ls -l
    total 0
    drwxr-xr-x. 2 root root 0 Aug 20 21:20 db
    drwxr-xr-x. 2 root root 0 Aug 20 21:20 KEK
    drwxr-xr-x. 2 root root 0 Aug 20 21:20 PK

  The attributes of each of the secure variables are (for example: PK):
    $ ls -l
    total 0
    -r--r--r--. 1 root root  4096 Oct  1 15:10 data
    -r--r--r--. 1 root root 65536 Oct  1 15:10 size
    --w-------. 1 root root  4096 Oct  1 15:12 update

  The "data" is used to read the existing variable value using
  hexdump. The data is stored in ESL format. The "update" is used to
  write a new value using cat. The update is to be submitted as AUTH
  file.

4 files changed, 147 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index a3ac9646119d..c0f8120045c3 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -20,3 +20,4 @@ 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_SCOM_DEBUGFS) += opal-xscom.o
+obj-$(CONFIG_PPC_SECURE_BOOT) += opal-secvar.o
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index a2aa5e433ac8..5cd0f52d258f 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -290,3 +290,6 @@ OPAL_CALL(opal_nx_coproc_init,			OPAL_NX_COPROC_INIT);
 OPAL_CALL(opal_mpipl_update,			OPAL_MPIPL_UPDATE);
 OPAL_CALL(opal_mpipl_register_tag,		OPAL_MPIPL_REGISTER_TAG);
 OPAL_CALL(opal_mpipl_query_tag,			OPAL_MPIPL_QUERY_TAG);
+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..14133e120bdd
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-secvar.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PowerNV code for secure variables
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Claudio Carvalho
+ *         Nayna Jain
+ *
+ * APIs to access secure variables managed by OPAL.
+ */
+
+#define pr_fmt(fmt) "secvar: "fmt
+
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <asm/opal.h>
+#include <asm/secvar.h>
+#include <asm/secure_boot.h>
+
+static int opal_status_to_err(int rc)
+{
+	int err;
+
+	switch (rc) {
+	case OPAL_SUCCESS:
+		err = 0;
+		break;
+	case OPAL_UNSUPPORTED:
+		err = -ENXIO;
+		break;
+	case OPAL_PARAMETER:
+		err = -EINVAL;
+		break;
+	case OPAL_RESOURCE:
+		err = -ENOSPC;
+		break;
+	case OPAL_HARDWARE:
+		err = -EIO;
+		break;
+	case OPAL_NO_MEM:
+		err = -ENOMEM;
+		break;
+	case OPAL_EMPTY:
+		err = -ENOENT;
+		break;
+	case OPAL_PARTIAL:
+		err = -EFBIG;
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static int opal_get_variable(const char *key, uint64_t ksize,
+			     u8 *data, uint64_t *dsize)
+{
+	int rc;
+
+	if (!key || !dsize)
+		return -EINVAL;
+
+	*dsize = cpu_to_be64(*dsize);
+
+	rc = opal_secvar_get(key, ksize, data, dsize);
+
+	*dsize = be64_to_cpu(*dsize);
+
+	return opal_status_to_err(rc);
+}
+
+static int opal_get_next_variable(const char *key, uint64_t *keylen,
+				  uint64_t keybufsize)
+{
+	int rc;
+
+	if (!key || !keylen)
+		return -EINVAL;
+
+	*keylen = cpu_to_be64(*keylen);
+
+	rc = opal_secvar_get_next(key, keylen, keybufsize);
+
+	*keylen = be64_to_cpu(*keylen);
+
+	return opal_status_to_err(rc);
+}
+
+static int opal_set_variable(const char *key, uint64_t ksize, u8 *data,
+			     uint64_t dsize)
+{
+	int rc;
+
+	if (!key || !data)
+		return -EINVAL;
+
+	rc = opal_secvar_enqueue_update(key, ksize, data, dsize);
+
+	return opal_status_to_err(rc);
+}
+
+static const struct secvar_operations opal_secvar_ops = {
+	.get = opal_get_variable,
+	.get_next = opal_get_next_variable,
+	.set = opal_set_variable,
+};
+
+static int opal_secvar_probe(struct platform_device *pdev)
+{
+	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");
+		return -ENODEV;
+	}
+
+	set_secvar_ops(&opal_secvar_ops);
+
+	return 0;
+}
+
+static const struct of_device_id opal_secvar_match[] = {
+	{ .compatible = "ibm,secvar-backend",},
+	{},
+};
+
+static struct platform_driver opal_secvar_driver = {
+	.driver = {
+		.name = "secvar",
+		.of_match_table = opal_secvar_match,
+	},
+};
+
+static int __init opal_secvar_init(void)
+{
+	return platform_driver_probe(&opal_secvar_driver, opal_secvar_probe);
+}
+device_initcall(opal_secvar_init);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index b1d064842da4..a6ee08009f0f 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -1084,6 +1084,9 @@ static int __init opal_init(void)
 	/* Initialise OPAL Power control interface */
 	opal_power_control_init();
 
+	/* Initialize OPAL secure variables */
+	opal_pdev_init("ibm,secvar-backend");
+
 	return 0;
 }
 machine_subsys_initcall(powernv, opal_init);