The dell-smbios stack only currently uses an SMI interface which grants
direct access to physical memory to the firmware SMM methods via a pointer.
This dispatcher driver adds a WMI-ACPI interface that is detected by WMI
probe and preferred over the SMI interface in dell-smbios.
Changing this to operate over WMI-ACPI will use an ACPI OperationRegion
for a buffer of data storage when SMM calls are performed.
This is a safer approach to use in kernel drivers as the SMM will
only have access to that OperationRegion.
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
Reviewed-by: Edward O'Callaghan <quasisec@xxxxxxxxxx>
---
MAINTAINERS | 6 +
drivers/platform/x86/Kconfig | 14 ++
drivers/platform/x86/Makefile | 1 +
drivers/platform/x86/dell-smbios-wmi.c | 236 +++++++++++++++++++++++++++++++++
4 files changed, 257 insertions(+)
create mode 100644 drivers/platform/x86/dell-smbios-wmi.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 9dc1ee9603e7..8fd2f0d2ddf6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3991,6 +3991,12 @@ L: platform-driver-x86@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/platform/x86/dell-smbios-smm.c
+DELL SMBIOS WMI DRIVER
+M: Mario Limonciello <mario.limonciello@xxxxxxxx>
+L: platform-driver-x86@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/platform/x86/dell-smbios-wmi.c
+
DELL LAPTOP DRIVER
M: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
M: Pali Rohár <pali.rohar@xxxxxxxxx>
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 53a2de781de6..83aee9068c64 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -94,6 +94,20 @@ config ASUS_LAPTOP
config DELL_SMBIOS
tristate
+config DELL_SMBIOS_WMI
+ tristate "Dell SMBIOS calling interface (WMI implementation)"
+ depends on ACPI_WMI
+ select DELL_WMI_DESCRIPTOR
+ default ACPI_WMI
+ select DELL_SMBIOS
+ ---help---
+ This provides an implementation for the Dell SMBIOS calling interface
+ communicated over ACPI-WMI.
+
+ If you have a Dell computer from >2007 you should say Y or M here.
+ If you aren't sure and this module doesn't work for your computer
+ it just won't load.
+
config DELL_SMBIOS_SMM
tristate "Dell SMBIOS calling interface (SMM implementation)"
depends on DCDBAS
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index e743615241f8..1c4234861de0 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_MSI_LAPTOP) += msi-laptop.o
obj-$(CONFIG_ACPI_CMPC) += classmate-laptop.o
obj-$(CONFIG_COMPAL_LAPTOP) += compal-laptop.o
obj-$(CONFIG_DELL_SMBIOS) += dell-smbios.o
+obj-$(CONFIG_DELL_SMBIOS_WMI) += dell-smbios-wmi.o
obj-$(CONFIG_DELL_SMBIOS_SMM) += dell-smbios-smm.o
obj-$(CONFIG_DELL_LAPTOP) += dell-laptop.o
obj-$(CONFIG_DELL_WMI) += dell-wmi.o
diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-smbios-wmi.c
new file mode 100644
index 000000000000..d2b8438ea91f
--- /dev/null
+++ b/drivers/platform/x86/dell-smbios-wmi.c
@@ -0,0 +1,236 @@
+/*
+ * WMI methods for use with dell-smbios
+ *
+ * Copyright (c) 2017 Dell Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/dmi.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/uaccess.h>
+#include <linux/wmi.h>
+#include "dell-smbios.h"
+#include "dell-wmi-descriptor.h"
+
+static DEFINE_MUTEX(call_mutex);
+static DEFINE_MUTEX(list_mutex);
+static int wmi_supported;
+
+struct misc_bios_flags_structure {
+ struct dmi_header header;
+ u16 flags0;
+} __packed;
+#define FLAG_HAS_ACPI_WMI 0x02
+
+#define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492"
+
+struct dell_wmi_extensions {
+ __u32 argattrib;
+ __u32 blength;
+ __u8 data[];
+} __packed;
+
+struct dell_wmi_smbios_buffer {
+ struct calling_interface_buffer std;
+ struct dell_wmi_extensions ext;
+} __packed;
+
+struct wmi_smbios_priv {
+ struct dell_wmi_smbios_buffer *buf;
+ struct list_head list;
+ struct wmi_device *wdev;
+ struct device *child;
+ u32 req_buf_size;
+};
+static LIST_HEAD(wmi_list);
+
+static inline struct wmi_smbios_priv *get_first_smbios_priv(void)
+{
+ return list_first_entry_or_null(&wmi_list,
+ struct wmi_smbios_priv,
+ list);
+}
+
+static int run_smbios_call(struct wmi_device *wdev)
+{
+ struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
+ struct wmi_smbios_priv *priv;
+ struct acpi_buffer input;
+ union acpi_object *obj;
+ acpi_status status;
+
+ priv = dev_get_drvdata(&wdev->dev);
+ input.length = priv->req_buf_size - sizeof(u64);
+ input.pointer = &priv->buf->std;
+
+ dev_dbg(&wdev->dev, "evaluating: %u/%u [%x,%x,%x,%x]\n",
+ priv->buf->std.class, priv->buf->std.select,
+ priv->buf->std.input[0], priv->buf->std.input[1],
+ priv->buf->std.input[2], priv->buf->std.input[3]);
+
+ status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
+ if (ACPI_FAILURE(status))
+ return -EIO;
+ obj = (union acpi_object *)output.pointer;
+ if (obj->type != ACPI_TYPE_BUFFER) {
+ dev_dbg(&wdev->dev, "received type: %d\n", obj->type);
+ if (obj->type == ACPI_TYPE_INTEGER)
+ dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n",
+ obj->integer.value);
+ return -EIO;
+ }
+ memcpy(&priv->buf->std, obj->buffer.pointer, obj->buffer.length);
+ dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n",
+ priv->buf->std.output[0], priv->buf->std.output[1],
+ priv->buf->std.output[2], priv->buf->std.output[3]);
+
+ return 0;
+}
+
+int dell_smbios_wmi_call(struct calling_interface_buffer *buffer)
+{
+ struct wmi_smbios_priv *priv;
+ size_t difference;
+ size_t size;
+ int ret;
+
+ mutex_lock(&call_mutex);
+ priv = get_first_smbios_priv();
+ if (!priv)
+ return -ENODEV;
+
+ size = sizeof(struct calling_interface_buffer);
+ difference = priv->req_buf_size - sizeof(u64) - size;
+
+ memset(&priv->buf->ext, 0, difference);
+ memcpy(&priv->buf->std, buffer, size);
+ ret = run_smbios_call(priv->wdev);
+ memcpy(buffer, &priv->buf->std, size);
+ mutex_unlock(&call_mutex);
+
+ return ret;
+}
+
+static int dell_smbios_wmi_probe(struct wmi_device *wdev)
+{
+ struct wmi_smbios_priv *priv;
+ int count;
+ int ret;
+
+ if (!wmi_has_guid(DELL_WMI_DESCRIPTOR_GUID))
+ return -ENODEV;
+
+ priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ /* WMI buffer size will be either 4k or 32k depending on machine */
+ if (!dell_wmi_get_size(&priv->req_buf_size))
+ return -EPROBE_DEFER;
+
+ count = get_order(priv->req_buf_size);
+ priv->buf = (void *)__get_free_pages(GFP_KERNEL, count);
+ if (!priv->buf)
+ return -ENOMEM;
+
+ /* ID is used by dell-smbios to set priority of drivers */
+ wdev->dev.id = 1;
+ ret = dell_smbios_register_device(&wdev->dev, &dell_smbios_wmi_call);
+ if (ret)
+ goto fail_register;
+
+ priv->wdev = wdev;
+ dev_set_drvdata(&wdev->dev, priv);
+ mutex_lock(&list_mutex);
+ list_add_tail(&priv->list, &wmi_list);
+ mutex_unlock(&list_mutex);
+
+ return 0;
+
+fail_register:
+ free_pages((unsigned long)priv->buf, count);
+ return ret;
+}
+
+static int dell_smbios_wmi_remove(struct wmi_device *wdev)
+{
+ struct wmi_smbios_priv *priv = dev_get_drvdata(&wdev->dev);
+ int count;
+
+ mutex_lock(&call_mutex);
+ mutex_lock(&list_mutex);
+ list_del(&priv->list);
+ mutex_unlock(&list_mutex);
+ dell_smbios_unregister_device(&wdev->dev);
+ count = get_order(priv->req_buf_size);
+ free_pages((unsigned long)priv->buf, count);
+ mutex_unlock(&call_mutex);
+ return 0;
+}
+
+static const struct wmi_device_id dell_smbios_wmi_id_table[] = {
+ { .guid_string = DELL_WMI_SMBIOS_GUID },
+ { },
+};
+
+static void __init parse_b1_table(const struct dmi_header *dm)
+{
+ struct misc_bios_flags_structure *flags =
+ container_of(dm, struct misc_bios_flags_structure, header);
+
+ /* 4 bytes header, 8 bytes flags */
+ if (dm->length < 12)
+ return;
+ if (dm->handle != 0xb100)
+ return;
+ if ((flags->flags0 & FLAG_HAS_ACPI_WMI))
+ wmi_supported = 1;
+}
+
+static void __init find_b1(const struct dmi_header *dm, void *dummy)
+{
+ switch (dm->type) {
+ case 0xb1: /* misc bios flags */
+ parse_b1_table(dm);
+ break;
+ }
+}
+
+static struct wmi_driver dell_smbios_wmi_driver = {
+ .driver = {
+ .name = "dell-smbios",
+ },
+ .probe = dell_smbios_wmi_probe,
+ .remove = dell_smbios_wmi_remove,
+ .id_table = dell_smbios_wmi_id_table,
+};
+
+static int __init init_dell_smbios_wmi(void)
+{
+ dmi_walk(find_b1, NULL);
+
+ if (!wmi_supported)
+ return -ENODEV;
+
+ return wmi_driver_register(&dell_smbios_wmi_driver);
+}
+
+static void __exit exit_dell_smbios_wmi(void)
+{
+ wmi_driver_unregister(&dell_smbios_wmi_driver);
+}
+
+module_init(init_dell_smbios_wmi);
+module_exit(exit_dell_smbios_wmi);
+
+MODULE_ALIAS("wmi:" DELL_WMI_SMBIOS_GUID);
+MODULE_AUTHOR("Mario Limonciello <mario.limonciello@xxxxxxxx>");
+MODULE_DESCRIPTION("Dell SMBIOS communications over WMI");
+MODULE_LICENSE("GPL");
--
2.14.1
