[PATCH v17 11/13] hp-bioscfg: surestart-attributes

[Jorge Lopez]

Add Sure Start attributes support to hp-bioscfg.

HP BIOS Configuration driver purpose is to provide a driver supporting
the latest sysfs class firmware attributes framework allowing the user
to change BIOS settings and security solutions on HP Inc.’s commercial
notebooks.

Signed-off-by: Jorge Lopez <jorge.lopez2@xxxxxx>

---
Based on the latest platform-drivers-x86.git/for-next
---
 .../x86/hp/hp-bioscfg/surestart-attributes.c  | 132 ++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 drivers/platform/x86/hp/hp-bioscfg/surestart-attributes.c

diff --git a/drivers/platform/x86/hp/hp-bioscfg/surestart-attributes.c b/drivers/platform/x86/hp/hp-bioscfg/surestart-attributes.c
new file mode 100644
index 000000000000..b57e42f29282
--- /dev/null
+++ b/drivers/platform/x86/hp/hp-bioscfg/surestart-attributes.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions corresponding to sure start object type attributes under
+ * BIOS for use with hp-bioscfg driver
+ *
+ * Copyright (c) 2022 HP Development Company, L.P.
+ */
+
+#include "bioscfg.h"
+#include <linux/types.h>
+
+/* Maximum number of log entries supported when log entry size is 16
+ * bytes. This value is calculated by dividing 4096 (page size) by
+ * log entry size.
+ */
+#define LOG_MAX_ENTRIES		254
+
+/*
+ * Current Log entry size. This value size will change in the
+ * future. The driver reads a total of 128 bytes for each log entry
+ * provided by BIOS but only the first 16 bytes are used/read.
+ */
+#define LOG_ENTRY_SIZE		16
+
+/*
+ * audit_log_entry_count_show - Reports the number of
+ *				existing audit log entries available
+ *				to be read
+ */
+static ssize_t audit_log_entry_count_show(struct kobject *kobj,
+					  struct kobj_attribute *attr, char *buf)
+{
+	int ret;
+	u32 count = 0;
+
+	ret = hp_wmi_perform_query(HPWMI_SURESTART_GET_LOG_COUNT,
+				   HPWMI_SURESTART,
+				   &count, 1, sizeof(count));
+
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d,%d,%d\n", count, LOG_ENTRY_SIZE,
+			  LOG_MAX_ENTRIES);
+}
+
+/*
+ * audit_log_entries_show() - Return all entries found in log file
+ */
+static ssize_t audit_log_entries_show(struct kobject *kobj,
+				      struct kobj_attribute *attr, char *buf)
+{
+	int ret;
+	int i;
+	u32 count = 0;
+	u8 audit_log_buffer[128];
+
+	// Get the number of event logs
+	ret = hp_wmi_perform_query(HPWMI_SURESTART_GET_LOG_COUNT,
+				   HPWMI_SURESTART,
+				   &count, 1, sizeof(count));
+
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * The show() api will not work if the audit logs ever go
+	 * beyond 4KB
+	 */
+	if (count * LOG_ENTRY_SIZE > PAGE_SIZE)
+		return -EIO;
+
+	/*
+	 * We are guaranteed the buffer is 4KB so today all the event
+	 * logs will fit
+	 */
+	for (i = 0; i < count; i++) {
+		audit_log_buffer[0] = i + 1;
+
+		/*
+		 * read audit log entry at a time. 'buf' input value
+		 * provides the audit log entry to be read. On
+		 * input, Byte 0 = Audit Log entry number from
+		 * beginning (1..254)
+		 * Entry number 1 is the newest entry whereas the
+		 * highest entry number (number of entries) is the
+		 * oldest entry.
+		 */
+		ret = hp_wmi_perform_query(HPWMI_SURESTART_GET_LOG,
+					   HPWMI_SURESTART,
+					   audit_log_buffer, 1, 128);
+
+		if (ret < 0 || (LOG_ENTRY_SIZE * i) > PAGE_SIZE) {
+			/*
+			 * Encountered a failure while reading
+			 * individual logs. Only a partial list of
+			 * audit log will be returned.
+			 */
+			break;
+		} else {
+			memcpy(buf, audit_log_buffer, LOG_ENTRY_SIZE);
+			buf += LOG_ENTRY_SIZE;
+		}
+	}
+
+	return i * LOG_ENTRY_SIZE;
+}
+
+static struct kobj_attribute sure_start_audit_log_entry_count = __ATTR_RO(audit_log_entry_count);
+static struct kobj_attribute sure_start_audit_log_entries = __ATTR_RO(audit_log_entries);
+
+static struct attribute *sure_start_attrs[] = {
+	&sure_start_audit_log_entry_count.attr,
+	&sure_start_audit_log_entries.attr,
+	NULL
+};
+
+static const struct attribute_group sure_start_attr_group = {
+	.attrs = sure_start_attrs,
+};
+
+void hp_exit_sure_start_attributes(void)
+{
+	sysfs_remove_group(bioscfg_drv.sure_start_attr_kobj,
+			   &sure_start_attr_group);
+}
+
+int hp_populate_sure_start_data(struct kobject *attr_name_kobj)
+{
+	bioscfg_drv.sure_start_attr_kobj = attr_name_kobj;
+	return sysfs_create_group(attr_name_kobj, &sure_start_attr_group);
+}
-- 
2.34.1