Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
From:   Tony Luck <tony.luck@intel.com>
To:     hdegoede@redhat.com, markgross@kernel.org
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
        corbet@lwn.net, gregkh@linuxfoundation.org,
        andriy.shevchenko@linux.intel.com, jithu.joseph@intel.com,
        ashok.raj@intel.com, tony.luck@intel.com, rostedt@goodmis.org,
        dan.j.williams@intel.com, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, platform-driver-x86@vger.kernel.org,
        patches@lists.linux.dev, ravi.v.shankar@intel.com
Subject: [PATCH v4 04/10] platform/x86/intel/ifs: Read IFS firmware image
Date:   Fri, 22 Apr 2022 13:02:13 -0700
Message-Id: <20220422200219.2843823-5-tony.luck@intel.com>
In-Reply-To: <20220422200219.2843823-1-tony.luck@intel.com>
References: <20220419163859.2228874-1-tony.luck@intel.com>
 <20220422200219.2843823-1-tony.luck@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Jithu Joseph <jithu.joseph@intel.com>

Driver probe routine allocates structure to communicate status
and parameters between functions in the driver. Also call
load_ifs_binary() to load the scan image file.

There is a separate scan image file for each processor family,
model, stepping combination. This is read from the static path:

  /lib/firmware/intel/ifs/{ff-mm-ss}.scan

Step 1 in loading is to generate the correct path and use
request_firmware_direct() to load into memory.

Subsequent patches will use the IFS MSR interfaces to copy
the image to BIOS reserved memory and validate the SHA256
checksums.

Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 drivers/platform/x86/intel/ifs/Makefile |  2 +-
 drivers/platform/x86/intel/ifs/core.c   | 36 ++++++++++++++++++++++++-
 drivers/platform/x86/intel/ifs/ifs.h    | 25 +++++++++++++++++
 drivers/platform/x86/intel/ifs/load.c   | 28 +++++++++++++++++++
 4 files changed, 89 insertions(+), 2 deletions(-)
 create mode 100644 drivers/platform/x86/intel/ifs/ifs.h
 create mode 100644 drivers/platform/x86/intel/ifs/load.c

diff --git a/drivers/platform/x86/intel/ifs/Makefile b/drivers/platform/x86/intel/ifs/Makefile
index af904880e959..98b6fde15689 100644
--- a/drivers/platform/x86/intel/ifs/Makefile
+++ b/drivers/platform/x86/intel/ifs/Makefile
@@ -1,3 +1,3 @@
 obj-$(CONFIG_INTEL_IFS)		+= intel_ifs.o
 
-intel_ifs-objs			:= core.o
+intel_ifs-objs			:= core.o load.o
diff --git a/drivers/platform/x86/intel/ifs/core.c b/drivers/platform/x86/intel/ifs/core.c
index 5713e6ee90f0..ed4ded6755b2 100644
--- a/drivers/platform/x86/intel/ifs/core.c
+++ b/drivers/platform/x86/intel/ifs/core.c
@@ -6,6 +6,8 @@
 
 #include <asm/cpu_device_id.h>
 
+#include "ifs.h"
+
 enum test_types {
 	IFS_SAF,
 };
@@ -20,10 +22,27 @@ static const struct x86_cpu_id ifs_cpu_ids[] __initconst = {
 };
 MODULE_DEVICE_TABLE(x86cpu, ifs_cpu_ids);
 
+static struct ifs_device ifs_devices[] = {
+	[IFS_SAF] = {
+		.data = {
+			.integrity_cap_bit = MSR_INTEGRITY_CAPS_PERIODIC_BIST_BIT,
+		},
+		.misc = {
+			.name = "intel_ifs_0",
+			.nodename = "intel_ifs/0",
+			.minor = MISC_DYNAMIC_MINOR,
+		},
+	},
+};
+
+#define IFS_NUMTESTS ARRAY_SIZE(ifs_devices)
+
 static int __init ifs_init(void)
 {
 	const struct x86_cpu_id *m;
+	int ndevices = 0;
 	u64 msrval;
+	int i;
 
 	m = x86_match_cpu(ifs_cpu_ids);
 	if (!m)
@@ -38,11 +57,26 @@ static int __init ifs_init(void)
 	if (rdmsrl_safe(MSR_INTEGRITY_CAPS, &msrval))
 		return -ENODEV;
 
-	return 0;
+	for (i = 0; i < IFS_NUMTESTS; i++) {
+		if (!(msrval & BIT(ifs_devices[i].data.integrity_cap_bit)))
+			continue;
+
+		if (!misc_register(&ifs_devices[i].misc)) {
+			ndevices++;
+			ifs_load_firmware(ifs_devices[i].misc.this_device);
+		}
+	}
+
+	return ndevices ? 0 : -ENODEV;
 }
 
 static void __exit ifs_exit(void)
 {
+	int i;
+
+	for (i = 0; i < IFS_NUMTESTS; i++)
+		if (ifs_devices[i].misc.this_device)
+			misc_deregister(&ifs_devices[i].misc);
 }
 
 module_init(ifs_init);
diff --git a/drivers/platform/x86/intel/ifs/ifs.h b/drivers/platform/x86/intel/ifs/ifs.h
new file mode 100644
index 000000000000..9a0f8e2077e2
--- /dev/null
+++ b/drivers/platform/x86/intel/ifs/ifs.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2022 Intel Corporation. */
+
+#ifndef _IFS_H_
+#define _IFS_H_
+
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+
+/**
+ * struct ifs_data - attributes related to intel IFS driver
+ * @integrity_cap_bit - MSR_INTEGRITY_CAPS bit enumerating this test
+ */
+struct ifs_data {
+	int integrity_cap_bit;
+};
+
+struct ifs_device {
+	struct ifs_data data;
+	struct miscdevice misc;
+};
+
+void ifs_load_firmware(struct device *dev);
+
+#endif
diff --git a/drivers/platform/x86/intel/ifs/load.c b/drivers/platform/x86/intel/ifs/load.c
new file mode 100644
index 000000000000..9fb71d38c819
--- /dev/null
+++ b/drivers/platform/x86/intel/ifs/load.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2022 Intel Corporation. */
+
+#include <linux/firmware.h>
+
+#include "ifs.h"
+
+/*
+ * Load ifs image. Before loading ifs module, the ifs image must be located
+ * in /lib/firmware/intel/ifs and named as {family/model/stepping}.{testname}.
+ */
+void ifs_load_firmware(struct device *dev)
+{
+	const struct firmware *fw;
+	char scan_path[32];
+	int ret;
+
+	snprintf(scan_path, sizeof(scan_path), "intel/ifs/%02x-%02x-%02x.scan",
+		 boot_cpu_data.x86, boot_cpu_data.x86_model, boot_cpu_data.x86_stepping);
+
+	ret = request_firmware_direct(&fw, scan_path, dev);
+	if (ret) {
+		dev_err(dev, "ifs file %s load failed\n", scan_path);
+		return;
+	}
+
+	release_firmware(fw);
+}
-- 
2.35.1