platform/x86/intel/ifs: Read IFS firmware image

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.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
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>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220506225410.1652287-6-tony.luck@intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/intel/ifs/Makefile b/drivers/platform/x86/intel/ifs/Makefile
index af90488..98b6fde 100644 (file)
--- 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 e3623ac..f62578d 100644 (file)
--- 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"
+
 #define X86_MATCH(model)                               \
        X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6,    \
                INTEL_FAM6_##model, X86_FEATURE_CORE_CAPABILITIES, NULL)
@@ -16,6 +18,17 @@ static const struct x86_cpu_id ifs_cpu_ids[] __initconst = {
 };
 MODULE_DEVICE_TABLE(x86cpu, ifs_cpu_ids);
 
+static struct ifs_device ifs_device = {
+       .data = {
+               .integrity_cap_bit = MSR_INTEGRITY_CAPS_PERIODIC_BIST_BIT,
+       },
+       .misc = {
+               .name = "intel_ifs_0",
+               .nodename = "intel_ifs/0",
+               .minor = MISC_DYNAMIC_MINOR,
+       },
+};
+
 static int __init ifs_init(void)
 {
        const struct x86_cpu_id *m;
@@ -34,11 +47,18 @@ static int __init ifs_init(void)
        if (rdmsrl_safe(MSR_INTEGRITY_CAPS, &msrval))
                return -ENODEV;
 
-       return 0;
+       if ((msrval & BIT(ifs_device.data.integrity_cap_bit)) &&
+           !misc_register(&ifs_device.misc)) {
+               ifs_load_firmware(ifs_device.misc.this_device);
+               return 0;
+       }
+
+       return -ENODEV;
 }
 
 static void __exit ifs_exit(void)
 {
+       misc_deregister(&ifs_device.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 (file)
index 0000000..9d15132
--- /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 (file)
index 0000000..9fb71d3
--- /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);
+}