Re: [PATCH v6 2/4] drivers/acpi: Introduce Platform Firmware Runtime Update device driver

Greg Kroah-Hartman
2021-10-25T06:47:46Z

On Mon, Oct 25, 2021 at 02:25:16PM +0800, Chen Yu wrote:
> Introduce the pfru_update driver which can be used for Platform Firmware
> Runtime code injection and driver update [1]. The user is expected to
> provide the update firmware in the form of capsule file, and pass it to
> the driver via ioctl. Then the driver would hand this capsule file to the
> Platform Firmware Runtime Update via the ACPI device _DSM method. At last
> the low level Management Mode would do the firmware update.
>
> The corresponding userspace tool and man page will be introduced at
> tools/power/acpi/pfru.
>
> Link: https://uefi.org/sites/default/files/resources/Intel_MM_OS_Interface_Spec_Rev100.pdf # [1]
> Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> ---
> v6: Use Link: tag to add the specification download address.
> (Andy Shevchenko)
> Remove linux/uuid.h and use raw buffers to contain uuid.
> (Andy Shevchenko)
> Drop comma for each terminator entry in the enum structure.
> (Andy Shevchenko)
> Remove redundant 'else' in get_image_type().
> (Andy Shevchenko)
> Directly return results from the switch cases in adjust_efi_size()
> and pfru_ioctl().(Andy Shevchenko)
> Keep comment style consistent by removing the period for
> one line comment.
> (Andy Shevchenko)
> Remove devm_kfree() if .probe() failed.
> (Andy Shevchenko)
> v5: Remove Documentation/ABI/pfru, and move the content to kernel doc
> in include/uapi/linux/pfru.h (Greg Kroah-Hartman)
> Shrink the range of ioctl numbers declared in
> Documentation/userspace-api/ioctl/ioctl-number.rst
> from 16 to 8. (Greg Kroah-Hartman)
> Change global variable struct pfru_device *pfru_dev to
> per ACPI device. (Greg Kroah-Hartman)
> Unregister the misc device in acpi_pfru_remove().
> (Greg Kroah-Hartman)
> Convert the kzalloc() to devm_kzalloc() in the driver so
> as to avoid freeing the memory. (Greg Kroah-Hartman)
> Fix the compile error by declaring the pfru_log_ioctl() as
> static. (kernel test robot LKP)
> Change to global variable misc_device to per ACPI device.
> (Greg Kroah-Hartman)
> v4: Replace all pr_err() with dev_dbg() (Greg Kroah-Hartman,
> Rafael J. Wysocki)
> Returns ENOTTY rather than ENOIOCTLCMD if invalid ioctl command
> is provided. (Greg Kroah-Hartman)
> Remove compat ioctl. (Greg Kroah-Hartman)
> Rename /dev/pfru/pfru_update to /dev/acpi_pfru (Greg Kroah-Hartman)
> Simplify the check for element of the package in query_capability()
> (Rafael J. Wysocki)
> Remove the loop in query_capability(), query_buffer() and query
> the package elemenet directly. (Rafael J. Wysocki)
> Check the the number of elements in case the number of package
> elements is too small. (Rafael J. Wysocki)
> Doing the assignment as initialization in get_image_type().
> Meanwhile, returns the type or a negative error code in
> get_image_type(). (Rafael J. Wysocki)
> Put the comments inside the function. (Rafael J. Wysocki)
> Returns the size or a negative error code in adjust_efi_size()
> (Rafael J. Wysocki)
> Fix the return value from EFAULT to EINVAL if pfru_valid_revid()
> does not pass. (Rafael J. Wysocki)
> Change the write() to be the code injection/update, the read() to
> be telemetry retrieval and all of the rest to be ioctl()s under
> one special device file.(Rafael J. Wysocki)
> Putting empty code lines after an if () statement that is not
> followed by a block. (Rafael J. Wysocki)
> Remove "goto" tags to make the code more readable. (Rafael J. Wysocki)
> v3: Use __u32 instead of int and __64 instead of unsigned long
> in include/uapi/linux/pfru.h (Greg Kroah-Hartman)
> Rename the structure in uapi to start with a prefix pfru so as
> to avoid confusing in the global namespace. (Greg Kroah-Hartman)
> v2: Add sanity check for duplicated instance of ACPI device.
> Update the driver to work with allocated pfru_device objects.
> (Mike Rapoport)
> For each switch case pair, get rid of the magic case numbers
> and add a default clause with the error handling.
> (Mike Rapoport)
> Move the obj->type checks outside the switch to reduce redundancy.
> (Mike Rapoport)
> Parse the code_inj_id and drv_update_id at driver initialization time
> to reduce the re-parsing at runtime.(Mike Rapoport)
> Explain in detail how the size needs to be adjusted when doing
> version check.(Mike Rapoport)
> Rename parse_update_result() to dump_update_result()(Mike Rapoport)
> Remove redundant return.(Mike Rapoport)
> Do not expose struct capsulate_buf_info to uapi, since it is
> not needed in userspace.(Mike Rapoport)
> ---
> .../userspace-api/ioctl/ioctl-number.rst | 1 +
> drivers/acpi/Kconfig | 1 +
> drivers/acpi/Makefile | 1 +
> drivers/acpi/pfru/Kconfig | 13 +
> drivers/acpi/pfru/Makefile | 2 +
> drivers/acpi/pfru/pfru_update.c | 567 ++++++++++++++++++
> include/uapi/linux/pfru.h | 186 ++++++
> 7 files changed, 771 insertions(+)
> create mode 100644 drivers/acpi/pfru/Kconfig
> create mode 100644 drivers/acpi/pfru/Makefile
> create mode 100644 drivers/acpi/pfru/pfru_update.c
> create mode 100644 include/uapi/linux/pfru.h
>
> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
> index 2e8134059c87..6f7c86b6deb7 100644
> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> @@ -365,6 +365,7 @@ Code Seq# Include File Comments
> <mailto:aherrman@de.ibm.com>
> 0xE5 00-3F linux/fuse.h
> 0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
> +0xEE 00-08 uapi/linux/pfru.h Platform Firmware Runtime Update and Telemetry
> 0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
> <mailto:thomas@winischhofer.net>
> 0xF6 all LTTng Linux Trace Toolkit Next Generation
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index 1da360c51d66..1d8d2e2cefac 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -482,6 +482,7 @@ source "drivers/acpi/nfit/Kconfig"
> source "drivers/acpi/numa/Kconfig"
> source "drivers/acpi/apei/Kconfig"
> source "drivers/acpi/dptf/Kconfig"
> +source "drivers/acpi/pfru/Kconfig"
>
> config ACPI_WATCHDOG
> bool
> diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> index 3018714e87d9..9c2c5ddff6ec 100644
> --- a/drivers/acpi/Makefile
> +++ b/drivers/acpi/Makefile
> @@ -102,6 +102,7 @@ obj-$(CONFIG_ACPI_CPPC_LIB) += cppc_acpi.o
> obj-$(CONFIG_ACPI_SPCR_TABLE) += spcr.o
> obj-$(CONFIG_ACPI_DEBUGGER_USER) += acpi_dbg.o
> obj-$(CONFIG_ACPI_PPTT) += pptt.o
> +obj-$(CONFIG_ACPI_PFRU) += pfru/
>
> # processor has its own "processor." module_param namespace
> processor-y := processor_driver.o
> diff --git a/drivers/acpi/pfru/Kconfig b/drivers/acpi/pfru/Kconfig
> new file mode 100644
> index 000000000000..5b31675b173a
> --- /dev/null
> +++ b/drivers/acpi/pfru/Kconfig
> @@ -0,0 +1,13 @@
> +# SPDX-License-Identifier: GPL-2.0
> +config ACPI_PFRU
> + tristate "ACPI Platform Firmware Runtime Update (PFRU)"
> + depends on 64BIT
> + help
> + In order to reduce the system reboot times and update the platform firmware
> + in time, Platform Firmware Runtime Update is leveraged to patch the system
> + without reboot. This driver supports Platform Firmware Runtime Update,
> + which is composed of two parts: code injection and driver update. It also
> + allows telemetry data to be retrieved from the platform firmware.
> +
> + To compile this driver as a module, choose M here:
> + the module will be called pfru_update.
> diff --git a/drivers/acpi/pfru/Makefile b/drivers/acpi/pfru/Makefile
> new file mode 100644
> index 000000000000..098cbe80cf3d
> --- /dev/null
> +++ b/drivers/acpi/pfru/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_ACPI_PFRU) += pfru_update.o
> diff --git a/drivers/acpi/pfru/pfru_update.c b/drivers/acpi/pfru/pfru_update.c
> new file mode 100644
> index 000000000000..99a95b2ddc57
> --- /dev/null
> +++ b/drivers/acpi/pfru/pfru_update.c
> @@ -0,0 +1,567 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ACPI Platform Firmware Runtime Update Device Driver
> + *
> + * Copyright (C) 2021 Intel Corporation
> + * Author: Chen Yu <yu.c.chen@intel.com>
> + */
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/efi.h>
> +#include <linux/err.h>
> +#include <linux/errno.h>
> +#include <linux/file.h>
> +#include <linux/fs.h>
> +#include <linux/miscdevice.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/string.h>
> +#include <linux/uaccess.h>
> +#include <linux/uio.h>
> +#include <linux/uuid.h>
> +#include <uapi/linux/pfru.h>
> +
> +enum cap_index {
> + CAP_STATUS_IDX,
> + CAP_UPDATE_IDX,
> + CAP_CODE_TYPE_IDX,
> + CAP_FW_VER_IDX,
> + CAP_CODE_RT_VER_IDX,
> + CAP_DRV_TYPE_IDX,
> + CAP_DRV_RT_VER_IDX,
> + CAP_DRV_SVN_IDX,
> + CAP_PLAT_ID_IDX,
> + CAP_OEM_ID_IDX,
> + CAP_OEM_INFO_IDX,
> + CAP_NR_IDX
> +};
> +
> +enum buf_index {
> + BUF_STATUS_IDX,
> + BUF_EXT_STATUS_IDX,
> + BUF_ADDR_LOW_IDX,
> + BUF_ADDR_HI_IDX,
> + BUF_SIZE_IDX,
> + BUF_NR_IDX
> +};
> +
> +enum update_index {
> + UPDATE_STATUS_IDX,
> + UPDATE_EXT_STATUS_IDX,
> + UPDATE_AUTH_TIME_LOW_IDX,
> + UPDATE_AUTH_TIME_HI_IDX,
> + UPDATE_EXEC_TIME_LOW_IDX,
> + UPDATE_EXEC_TIME_HI_IDX,
> + UPDATE_NR_IDX
> +};
> +
> +struct pfru_device {
> + guid_t uuid, code_uuid, drv_uuid;
> + int rev_id;
> + struct device *dev;
> + struct miscdevice miscdev;
> +};
> +
> +static inline struct pfru_device *to_pfru_dev(struct file *file)
> +{
> + return container_of(file->private_data, struct pfru_device, miscdev);
> +}
> +
> +static int query_capability(struct pfru_update_cap_info *cap,
> + struct pfru_device *pfru_dev)
> +{
> + union acpi_object *out_obj;
> + acpi_handle handle;
> + int ret = -EINVAL;
> +
> + handle = ACPI_HANDLE(pfru_dev->dev);
> + out_obj = acpi_evaluate_dsm_typed(handle, &pfru_dev->uuid,
> + pfru_dev->rev_id,
> + FUNC_QUERY_UPDATE_CAP,
> + NULL, ACPI_TYPE_PACKAGE);
> + if (!out_obj)
> + return ret;
> +
> + if (out_obj->package.count < CAP_NR_IDX)
> + goto free_acpi_buffer;
> +
> + if (out_obj->package.elements[CAP_STATUS_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + cap->status = out_obj->package.elements[CAP_STATUS_IDX].integer.value;
> +
> + if (out_obj->package.elements[CAP_UPDATE_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + cap->update_cap = out_obj->package.elements[CAP_UPDATE_IDX].integer.value;
> +
> + if (out_obj->package.elements[CAP_CODE_TYPE_IDX].type != ACPI_TYPE_BUFFER)
> + goto free_acpi_buffer;
> +
> + memcpy(&cap->code_type,
> + out_obj->package.elements[CAP_CODE_TYPE_IDX].buffer.pointer,
> + out_obj->package.elements[CAP_CODE_TYPE_IDX].buffer.length);
> +
> + if (out_obj->package.elements[CAP_FW_VER_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + cap->fw_version =
> + out_obj->package.elements[CAP_FW_VER_IDX].integer.value;
> +
> + if (out_obj->package.elements[CAP_CODE_RT_VER_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + cap->code_rt_version =
> + out_obj->package.elements[CAP_CODE_RT_VER_IDX].integer.value;
> +
> + if (out_obj->package.elements[CAP_DRV_TYPE_IDX].type != ACPI_TYPE_BUFFER)
> + goto free_acpi_buffer;
> +
> + memcpy(&cap->drv_type,
> + out_obj->package.elements[CAP_DRV_TYPE_IDX].buffer.pointer,
> + out_obj->package.elements[CAP_DRV_TYPE_IDX].buffer.length);
> +
> + if (out_obj->package.elements[CAP_DRV_RT_VER_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + cap->drv_rt_version =
> + out_obj->package.elements[CAP_DRV_RT_VER_IDX].integer.value;
> +
> + if (out_obj->package.elements[CAP_DRV_SVN_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + cap->drv_svn =
> + out_obj->package.elements[CAP_DRV_SVN_IDX].integer.value;
> +
> + if (out_obj->package.elements[CAP_PLAT_ID_IDX].type != ACPI_TYPE_BUFFER)
> + goto free_acpi_buffer;
> +
> + memcpy(&cap->platform_id,
> + out_obj->package.elements[CAP_PLAT_ID_IDX].buffer.pointer,
> + out_obj->package.elements[CAP_PLAT_ID_IDX].buffer.length);
> +
> + if (out_obj->package.elements[CAP_OEM_ID_IDX].type != ACPI_TYPE_BUFFER)
> + goto free_acpi_buffer;
> +
> + memcpy(&cap->oem_id,
> + out_obj->package.elements[CAP_OEM_ID_IDX].buffer.pointer,
> + out_obj->package.elements[CAP_OEM_ID_IDX].buffer.length);
> + ret = 0;
> +free_acpi_buffer:
> + ACPI_FREE(out_obj);
> +
> + return ret;
> +}
> +
> +static int query_buffer(struct pfru_com_buf_info *info,
> + struct pfru_device *pfru_dev)
> +{
> + union acpi_object *out_obj;
> + acpi_handle handle;
> + int ret = -EINVAL;
> +
> + handle = ACPI_HANDLE(pfru_dev->dev);
> + out_obj = acpi_evaluate_dsm_typed(handle, &pfru_dev->uuid,
> + pfru_dev->rev_id, FUNC_QUERY_BUF,
> + NULL, ACPI_TYPE_PACKAGE);
> + if (!out_obj)
> + return ret;
> +
> + if (out_obj->package.count < BUF_NR_IDX)
> + goto free_acpi_buffer;
> +
> + if (out_obj->package.elements[BUF_STATUS_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + info->status = out_obj->package.elements[BUF_STATUS_IDX].integer.value;
> +
> + if (out_obj->package.elements[BUF_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + info->ext_status =
> + out_obj->package.elements[BUF_EXT_STATUS_IDX].integer.value;
> +
> + if (out_obj->package.elements[BUF_ADDR_LOW_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + info->addr_lo =
> + out_obj->package.elements[BUF_ADDR_LOW_IDX].integer.value;
> +
> + if (out_obj->package.elements[BUF_ADDR_HI_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + info->addr_hi =
> + out_obj->package.elements[BUF_ADDR_HI_IDX].integer.value;
> +
> + if (out_obj->package.elements[BUF_SIZE_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + info->buf_size = out_obj->package.elements[BUF_SIZE_IDX].integer.value;
> +
> + ret = 0;
> +free_acpi_buffer:
> + ACPI_FREE(out_obj);
> +
> + return ret;
> +}
> +
> +static int get_image_type(efi_manage_capsule_image_header_t *img_hdr,
> + struct pfru_device *pfru_dev)
> +{
> + guid_t *image_type_id = &img_hdr->image_type_id;
> +
> + /* check whether this is a code injection or driver update */
> + if (guid_equal(image_type_id, &pfru_dev->code_uuid))
> + return CODE_INJECT_TYPE;
> +
> + if (guid_equal(image_type_id, &pfru_dev->drv_uuid))
> + return DRIVER_UPDATE_TYPE;
> +
> + return -EINVAL;
> +}
> +
> +static int adjust_efi_size(efi_manage_capsule_image_header_t *img_hdr,
> + int size)
> +{
> + /*
> + * The (u64 hw_ins) was introduced in UEFI spec version 2,
> + * and (u64 capsule_support) was introduced in version 3.
> + * The size needs to be adjusted accordingly. That is to
> + * say, version 1 should subtract the size of hw_ins+capsule_support,
> + * and version 2 should sbstract the size of capsule_support.
> + */
> + size += sizeof(efi_manage_capsule_image_header_t);
> + switch (img_hdr->ver) {
> + case 1:
> + return size - 2 * sizeof(u64);
> + case 2:
> + return size - sizeof(u64);
> + default:
> + /* only support version 1 and 2 */
> + return -EINVAL;
> + }
> +}
> +
> +static bool valid_version(const void *data, struct pfru_update_cap_info *cap,
> + struct pfru_device *pfru_dev)
> +{
> + struct pfru_payload_hdr *payload_hdr;
> + efi_capsule_header_t *cap_hdr;
> + efi_manage_capsule_header_t *m_hdr;
> + efi_manage_capsule_image_header_t *m_img_hdr;
> + efi_image_auth_t *auth;
> + int type, size;
> +
> + /*
> + * Sanity check if the capsule image has a newer version
> + * than current one.
> + */
> + cap_hdr = (efi_capsule_header_t *)data;
> + size = cap_hdr->headersize;
> + m_hdr = (efi_manage_capsule_header_t *)(data + size);
> + /*
> + * Current data structure size plus variable array indicated
> + * by number of (emb_drv_cnt + payload_cnt)
> + */
> + size += sizeof(efi_manage_capsule_header_t) +
> + (m_hdr->emb_drv_cnt + m_hdr->payload_cnt) * sizeof(u64);
> + m_img_hdr = (efi_manage_capsule_image_header_t *)(data + size);
> +
> + type = get_image_type(m_img_hdr, pfru_dev);
> + if (type < 0)
> + return false;
> +
> + size = adjust_efi_size(m_img_hdr, size);
> + if (size < 0)
> + return false;
> +
> + auth = (efi_image_auth_t *)(data + size);
> + size += sizeof(u64) + auth->auth_info.hdr.len;
> + payload_hdr = (struct pfru_payload_hdr *)(data + size);
> +
> + /* finally compare the version */
> + if (type == CODE_INJECT_TYPE)
> + return payload_hdr->rt_ver >= cap->code_rt_version;
> + else
> + return payload_hdr->rt_ver >= cap->drv_rt_version;
> +}
> +
> +static void dump_update_result(struct pfru_updated_result *result,
> + struct pfru_device *pfru_dev)
> +{
> + dev_dbg(pfru_dev->dev, "Update result:\n");
> + dev_dbg(pfru_dev->dev, "Status:%d\n", result->status);
> + dev_dbg(pfru_dev->dev, "Extended Status:%d\n", result->ext_status);
> + dev_dbg(pfru_dev->dev, "Authentication Time Low:%lld\n",
> + result->low_auth_time);
> + dev_dbg(pfru_dev->dev, "Authentication Time High:%lld\n",
> + result->high_auth_time);
> + dev_dbg(pfru_dev->dev, "Execution Time Low:%lld\n",
> + result->low_exec_time);
> + dev_dbg(pfru_dev->dev, "Execution Time High:%lld\n",
> + result->high_exec_time);
> +}
> +
> +static int start_acpi_update(int action, struct pfru_device *pfru_dev)
> +{
> + union acpi_object *out_obj, in_obj, in_buf;
> + struct pfru_updated_result update_result;
> + acpi_handle handle;
> + int ret = -EINVAL;
> +
> + memset(&in_obj, 0, sizeof(in_obj));
> + memset(&in_buf, 0, sizeof(in_buf));
> + in_obj.type = ACPI_TYPE_PACKAGE;
> + in_obj.package.count = 1;
> + in_obj.package.elements = &in_buf;
> + in_buf.type = ACPI_TYPE_INTEGER;
> + in_buf.integer.value = action;
> +
> + handle = ACPI_HANDLE(pfru_dev->dev);
> + out_obj = acpi_evaluate_dsm_typed(handle, &pfru_dev->uuid,
> + pfru_dev->rev_id, FUNC_START,
> + &in_obj, ACPI_TYPE_PACKAGE);
> + if (!out_obj)
> + return ret;
> +
> + if (out_obj->package.count < UPDATE_NR_IDX)
> + goto free_acpi_buffer;
> +
> + if (out_obj->package.elements[UPDATE_STATUS_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + update_result.status =
> + out_obj->package.elements[UPDATE_STATUS_IDX].integer.value;
> +
> + if (out_obj->package.elements[UPDATE_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + update_result.ext_status =
> + out_obj->package.elements[UPDATE_EXT_STATUS_IDX].integer.value;
> +
> + if (out_obj->package.elements[UPDATE_AUTH_TIME_LOW_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + update_result.low_auth_time =
> + out_obj->package.elements[UPDATE_AUTH_TIME_LOW_IDX].integer.value;
> +
> + if (out_obj->package.elements[UPDATE_AUTH_TIME_HI_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + update_result.high_auth_time =
> + out_obj->package.elements[UPDATE_AUTH_TIME_HI_IDX].integer.value;
> +
> + if (out_obj->package.elements[UPDATE_EXEC_TIME_LOW_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + update_result.low_exec_time =
> + out_obj->package.elements[UPDATE_EXEC_TIME_LOW_IDX].integer.value;
> +
> + if (out_obj->package.elements[UPDATE_EXEC_TIME_HI_IDX].type != ACPI_TYPE_INTEGER)
> + goto free_acpi_buffer;
> +
> + update_result.high_exec_time =
> + out_obj->package.elements[UPDATE_EXEC_TIME_HI_IDX].integer.value;
> +
> + dump_update_result(&update_result, pfru_dev);
> + ret = 0;
> +
> +free_acpi_buffer:
> + ACPI_FREE(out_obj);
> +
> + return ret;
> +}
> +
> +static long pfru_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> + struct pfru_update_cap_info cap;
> + struct pfru_device *pfru_dev;
> + void __user *p;
> + int ret, rev;
> +
> + pfru_dev = to_pfru_dev(file);
> + p = (void __user *)arg;
> +
> + switch (cmd) {
> + case PFRU_IOC_QUERY_CAP:
> + ret = query_capability(&cap, pfru_dev);
> + if (ret)
> + return ret;
> +
> + if (copy_to_user(p, &cap, sizeof(cap)))
> + return -EFAULT;
> +
> + return 0;
> + case PFRU_IOC_SET_REV:
> + if (copy_from_user(&rev, p, sizeof(unsigned int)))
> + return -EFAULT;
> +
> + if (!pfru_valid_revid(rev))
> + return -EINVAL;
> +
> + pfru_dev->rev_id = rev;
> +
> + return 0;
> + case PFRU_IOC_STAGE:
> + return start_acpi_update(START_STAGE, pfru_dev);
> + case PFRU_IOC_ACTIVATE:
> + return start_acpi_update(START_ACTIVATE, pfru_dev);
> + case PFRU_IOC_STAGE_ACTIVATE:
> + return start_acpi_update(START_STAGE_ACTIVATE, pfru_dev);
> + default:
> + return -ENOTTY;
> + }
> +}
> +
> +static ssize_t pfru_write(struct file *file, const char __user *buf,
> + size_t len, loff_t *ppos)
> +{
> + struct pfru_update_cap_info cap;
> + struct pfru_com_buf_info info;
> + struct pfru_device *pfru_dev;
> + phys_addr_t phy_addr;
> + struct iov_iter iter;
> + struct iovec iov;
> + char *buf_ptr;
> + int ret;
> +
> + pfru_dev = to_pfru_dev(file);
> +
> + ret = query_buffer(&info, pfru_dev);
> + if (ret)
> + return ret;
> +
> + if (len > info.buf_size)
> + return -EINVAL;
> +
> + iov.iov_base = (void __user *)buf;
> + iov.iov_len = len;
> + iov_iter_init(&iter, WRITE, &iov, 1, len);
> +
> + /* map the communication buffer */
> + phy_addr = (phys_addr_t)(info.addr_lo | (info.addr_hi << 32));
> + buf_ptr = memremap(phy_addr, info.buf_size, MEMREMAP_WB);
> + if (IS_ERR(buf_ptr))
> + return PTR_ERR(buf_ptr);
> +
> + if (!copy_from_iter_full(buf_ptr, len, &iter)) {
> + ret = -EINVAL;
> + goto unmap;
> + }
> +
> + /* check if the capsule header has a valid version number */
> + ret = query_capability(&cap, pfru_dev);
> + if (ret)
> + goto unmap;
> +
> + if (cap.status != DSM_SUCCEED)
> + ret = -EBUSY;
> + else if (!valid_version(buf_ptr, &cap, pfru_dev))
> + ret = -EINVAL;
> +unmap:
> + memunmap(buf_ptr);
> +
> + return ret ?: len;
> +}
> +
> +static const struct file_operations acpi_pfru_fops = {
> + .owner = THIS_MODULE,
> + .write = pfru_write,
> + .unlocked_ioctl = pfru_ioctl,
> + .llseek = noop_llseek,
> +};
> +
> +static int acpi_pfru_remove(struct platform_device *pdev)
> +{
> + struct pfru_device *pfru_dev = platform_get_drvdata(pdev);
> +
> + misc_deregister(&pfru_dev->miscdev);
> +
> + return 0;
> +}
> +
> +static int acpi_pfru_probe(struct platform_device *pdev)
> +{
> + struct pfru_device *pfru_dev;
> + acpi_handle handle;
> + static int pfru_idx;

Why not use an ida/idr structure for this? You never decrement this
when the device is removed?

> + int ret;
> +
> + pfru_dev = devm_kzalloc(&pdev->dev, sizeof(*pfru_dev), GFP_KERNEL);
> + if (!pfru_dev)
> + return -ENOMEM;
> +
> + ret = guid_parse(PFRU_UUID, &pfru_dev->uuid);
> + if (ret)
> + return ret;
> +
> + ret = guid_parse(PFRU_CODE_INJ_UUID, &pfru_dev->code_uuid);
> + if (ret)
> + return ret;
> +
> + ret = guid_parse(PFRU_DRV_UPDATE_UUID, &pfru_dev->drv_uuid);
> + if (ret)
> + return ret;
> +
> + /* default rev id is 1 */
> + pfru_dev->rev_id = 1;
> + pfru_dev->dev = &pdev->dev;
> + handle = ACPI_HANDLE(pfru_dev->dev);
> + if (!acpi_has_method(handle, "_DSM")) {
> + dev_dbg(&pdev->dev, "Missing _DSM\n");
> + return -ENODEV;
> + }

Why not make this check first, before you allocate or parse anything?

> +
> + pfru_dev->miscdev.minor = MISC_DYNAMIC_MINOR;
> + pfru_dev->miscdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> + "pfru%d", pfru_idx);
> + if (!pfru_dev->miscdev.name)
> + return -ENOMEM;
> +
> + pfru_dev->miscdev.nodename = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> + "acpi_pfru%d", pfru_idx);
> + if (!pfru_dev->miscdev.nodename)
> + return -ENOMEM;
> +
> + pfru_idx++;
> + pfru_dev->miscdev.fops = &acpi_pfru_fops;
> +
> + ret = misc_register(&pfru_dev->miscdev);
> + if (ret)
> + return ret;

You forgot to set the parent of the misc device here, right? :(

> +
> + platform_set_drvdata(pdev, pfru_dev);
> +
> + return 0;
> +}
> +
> +static const struct acpi_device_id acpi_pfru_ids[] = {
> + {"INTC1080", 0},
> + {}
> +};
> +MODULE_DEVICE_TABLE(acpi, acpi_pfru_ids);
> +
> +static struct platform_driver acpi_pfru_driver = {
> + .driver = {
> + .name = "pfru_update",
> + .acpi_match_table = acpi_pfru_ids,
> + },
> + .probe = acpi_pfru_probe,
> + .remove = acpi_pfru_remove,
> +};
> +
> +static int __init pfru_init(void)
> +{
> + return platform_driver_register(&acpi_pfru_driver);
> +}
> +
> +static void __exit pfru_exit(void)
> +{
> + platform_driver_unregister(&acpi_pfru_driver);
> +}
> +
> +module_init(pfru_init);
> +module_exit(pfru_exit);

module_platform_driver()?

thanks,

greg k-h