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    Subject[PATCH v7 11/15] platform/x86: dell-smbios-wmi: Add new WMI dispatcher driver
    Date
    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@dell.com>
    ---
    MAINTAINERS | 6 +
    drivers/platform/x86/Kconfig | 14 ++
    drivers/platform/x86/Makefile | 1 +
    drivers/platform/x86/dell-smbios-wmi.c | 229 +++++++++++++++++++++++++++++++++
    4 files changed, 250 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@vger.kernel.org
    S: Maintained
    F: drivers/platform/x86/dell-smbios-smm.c

    +DELL SMBIOS WMI DRIVER
    +M: Mario Limonciello <mario.limonciello@dell.com>
    +L: platform-driver-x86@vger.kernel.org
    +S: Maintained
    +F: drivers/platform/x86/dell-smbios-wmi.c
    +
    DELL LAPTOP DRIVER
    M: Matthew Garrett <mjg59@srcf.ucam.org>
    M: Pali Rohár <pali.rohar@gmail.com>
    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..7b554ee0e9e6
    --- /dev/null
    +++ b/drivers/platform/x86/dell-smbios-wmi.c
    @@ -0,0 +1,229 @@
    +/*
    + * 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;
    + input.pointer = &priv->buf->std;
    +
    + dev_dbg(&wdev->dev, "evaluating: %x/%x [%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);
    +
    + 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;
    +
    + priv = get_first_smbios_priv();
    + if (!priv)
    + return -ENODEV;
    +
    + size = sizeof(struct calling_interface_buffer);
    + difference = priv->req_buf_size - sizeof(u64) - size;
    +
    + mutex_lock(&call_mutex);
    + 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;
    +
    + 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@dell.com>");
    +MODULE_DESCRIPTION("Dell SMBIOS communications over WMI");
    +MODULE_LICENSE("GPL");
    --
    2.14.1
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      Last update: 2017-10-11 18:29    [W:4.094 / U:0.056 seconds]
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