Introduce Platform Firmware Runtime Update and Telemetry drivers

The PFRUT(Platform Firmware Runtime Update and Telemetry) kernel interface is designed to interact with the platform firmware interface defined in the `Management Mode Firmware Runtime Update
<https://uefi.org/sites/default/files/resources/Intel_MM_OS_Interface_Spec_Rev100.pdf>`
specification. The primary function of PFRUT is to carry out runtime updates of the platform firmware, which doesn't require the system to be restarted. It also allows telemetry data to be retrieved from the platform firmware.

=============
- Change from v11 to v12:
- Rename the driver from pfru_update to pfr_update, and the telemetry part to pfr_telementry for symmetry.
(Rafael J. Wysocki)
- Rename the "capsule file" to "EFI capsule".
(Rafael J. Wysocki)
- Revise the commit log. (Rafael J. Wysocki)
- Add the reason in the commit log that explains why it is
a good idea to add this driver to the kernel.
(Rafael J. Wysocki)
- Rename pfru.h to pfrut.h (Rafael J. Wysocki)
- Rename the CONFIG_ACPI_PFRU to CONFIG_ACPI_PFRUT
(Rafael J. Wysocki)
- Rename the Kconfig name to "ACPI Platform Firmware Runtime Update and Telemetry"
(Rafael J. Wysocki)
- Revise the Kconfig help message (Rafael J. Wysocki)
- Describe what the driver is for briefly in the beginning of
the source code file.
(Rafael J. Wysocki)
- Add a comment pointing to the definitions of the GUIDs and explain briefly what they are for.
(Rafael J. Wysocki)
- Reduce redundant memory updates by doing all of the checks upfront. (Rafael J. Wysocki)
- Rename valid_version() to applicable_image(), and revise the comment.(Rafael J. Wysocki)
- Remove Redundant else in applicable_image().(Rafael J. Wysocki)
- Rename dump_update_result() to print_ipdate_debug_info(). (Rafael J. Wysocki)
- Rename start_acpi_update() to start_update()(Rafael J. Wysocki) Add a blank line before each "case xxx:"(Rafael J. Wysocki)
- Move status check into query_capability() and returns -EBUSY if fails(Rafael J. Wysocki)
- Rename the device node name from "acpi_pfru%d" to "acpi_pfr_update%d" (Rafael J. Wysocki)
- Rename the drive name from "pfru_update" to "pfr_update"
(Rafael J. Wysocki)
- Rename PFRU_MAGIC_FOR_IOCTL to PFRUT_IOCTL_MAGIC(Rafael J. Wysocki) Fix grammar errors in the comments.(Rafael J. Wysocki)
- Change from v10 to v11:
- Revise the commit log to explain why version check is introduced in kernel rather than letting Management Mode to do it.
(Rafael J. Wysocki)
- Revise the commit log to better describe the pack attribute. (Rafael J. Wysocki)
- Refine the comment for hw_ins and capsule_support.
(Rafael J. Wysocki)
- Change from v9 to v10:
- Remove the explicit assignment of the last item of enum.
(Andy Shevchenko)
- Change from v8 to v9:
- Use GUID_INIT() instead of guid_parse() during boot up.
(Andy Shevchenko)
- Drop uuid, code_uuid, drv_uuid in struct pfru_device as they
are not needed. (Andy Shevchenko)
- Drop type casting from void * in valid_version().
(Andy Shevchenko)
- Use kfree() instead of ACPI_FREE() in non-ACPICA usage.
(Andy Shevchenko)
- Use sizeof(rev) instead of sizeof(u32) in copy_from_user(). (Andy Shevchenko)
- Generate physical address from MSB part to LSB.
(Andy Shevchenko)
- Use devm_add_action_or_reset() to add ida release into dev resource management. (Andy Shevchenko)
- Use devm_kasprintf() instead of kasprintf() to format the pfru_dev name.(Andy Shevchenko)
- Remove redundant 0 in acpi_pfru_ids. (Andy Shevchenko)
- Adjust the order of included headers in pfru.h.
(Andy Shevchenko)
- Replace PFRU_MAGIC with PFRU_MAGIC_FOR_IOCTL in uapi file.
(Andy Shevchenko)
Use devm_kasprintf() instead of kasprintf() to format the pfru_log_dev name.(Andy Shevchenko)
Remove redundant 0 in acpi_pfru_log_ids. (Andy Shevchenko)
- Change from v7 to v8:
- Remove the variable-length array in struct pfru_update_cap_info, and copy the non-variable-length struct pfru_update_cap_info to userspace directly. (Greg Kroah-Hartman)
- Use efi_guid_t instead of guid_t when parsing capsule file. (Andy Shevchenko)
- Change the type of rev_id from int to u32, because this data will be copied between kernel and userspace. (Greg Kroah-Hartman)
- Add a prefix for dev in struct pfru_device to parent_dev, so as to indicate that this filed is the parent of the created miscdev. (Greg Kroah-Hartman)
- Use blank lines between different macro sections. (Greg Kroah-Hartman) Illusatrate the possible errno for each ioctl interface.
(Greg Kroah-Hartman)
- Remove pfru_valid_revid() from uapi header to avoid poluting the global namespace.(Greg Kroah-Hartman)
- Assign the value to the enum type explicitly.(Greg Kroah-Hartman)
- Change the guid_t to efi_guid_t when parsing image header in get_image_type() (Greg Kroah-Hartman)
- Remove the void * to other type casting in valid_version(). (Andy Shevchenko)
- Combined the assignment of variables with definitions. (Andy Shevchenko)
- Define this magic for revision ID. (Andy Shevchenko)
- Make the labeling consistent for error handling. (Andy Shevchenko)
- Replace the UUID_SIZE in uapi with 16 directly. (Andy Shevchenko)
- Add blank line between generic include header and uapi header. (Andy Shevchenko)
- Arrange the order between devm_kzalloc() and normal allocation in acpi_pfru_probe() that, the former should always be ahead of the latter. (Andy Shevchenko)
- Change from v6 to v7:
- Use __packed instead of pragma pack(1).
(Greg Kroah-Hartman, Ard Biesheuve)
- Use ida_alloc() to allocate a ID, and release the ID when
device is removed. (Greg Kroah-Hartman)
- Check the _DSM method at early stage, before allocate or parse anything in acpi_pfru_[log_]probe(). (Greg Kroah-Hartman)
- Set the parent of the misc device. (Greg Kroah-Hartman)
- Use module_platform_driver() instead of platform_driver_register() in module_init(). Separate pfru driver and pfru_telemetry driver to two files. (Greg Kroah-Hartman)
- Change from v5 to v6:
- Use Link: tag to add the specification download address.
(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 consistency by removing the period for
one line comment.
(Andy Shevchenko)
- Remove devm_kfree() if .probe() failed.
(Andy Shevchenko)
- Remove linux/uuid.h and use raw buffers to contain uuid.
(Andy Shevchenko)
- Include types.h in pfru.h. (Andy Shevchenko)
- Use __u8[16] instead of uuid_t. (Andy Shevchenko)
- Replace enum in pfru.h with __u32 as enum size is not the
same size on all possible architectures.
(Andy Shevchenko)
- Simplify the userspace tool to use while loop for getopt_long(). (Andy Shevchenko)
- Change from v4 to 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 PFRU 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 warning by declaring the pfru_log_ioctl() as static. (kernel test robot LKP)
- Change to global variable misc_device to per PFRU device.
(Greg Kroah-Hartman)
- Remove the telemetry output in commit log. (Greg Kroah-Hartman)
- Add link for corresponding userspace tool in the commit log. (Greg Kroah-Hartman)
- Replace the telemetry .read() with .mmap() so that the userspace could mmap once, and read multiple times. (Greg Kroah-Hartman)
- Change from v3 to v4:
- Add Documentation/ABI/testing/pfru to document the ABI and remove Documentation/x86/pfru.rst (Rafael J. Wysocki)
- 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 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)
- Remove redundant parens. (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)
- Change from v2 to v3:
- Use valid types for structures that cross the user/kernel boundary in the uapi header. (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)
- Change from v1 to v2:
- Add a spot in index.rst so it becomes part of the docs build (Jonathan Corbet).
- Sticking to the 80-column limit(Jonathan Corbet).
- Underline lengths should match the title text(Jonathan Corbet).
- Use literal blocks for the code samples(Jonathan Corbet).
- 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)
- Do not allow non-root user to run this test.(Shuah Khan)
- Test runs on platform without pfru_telemetry should skip
instead of reporting failure/error.(Shuah Khan)
- Reuse uapi/linux/pfru.h instead of copying it into the test directory. (Mike Rapoport)

Chen Yu (4):
efi: Introduce EFI_FIRMWARE_MANAGEMENT_CAPSULE_HEADER and
corresponding structures
drivers/acpi: Introduce Platform Firmware Runtime Update device driver drivers/acpi: Introduce Platform Firmware Runtime Telemetry
tools: Introduce power/acpi/tools/pfrut

 .../userspace-api/ioctl/ioctl-number.rst      |   1 +
 drivers/acpi/Kconfig                          |  22 +
 drivers/acpi/Makefile                         |   1 +
 drivers/acpi/pfr_telemetry.c                  | 433 ++++++++++++++
 drivers/acpi/pfr_update.c                     | 558 ++++++++++++++++++
 include/linux/efi.h                           |  46 ++
 include/uapi/linux/pfrut.h                    | 262 ++++++++
 tools/power/acpi/.gitignore                   |   1 +
 tools/power/acpi/Makefile                     |  16 +-
 tools/power/acpi/Makefile.rules               |   2 +-
 tools/power/acpi/man/pfrut.8                  | 137 +++++
 tools/power/acpi/tools/pfrut/Makefile         |  23 +
 tools/power/acpi/tools/pfrut/pfrut.c          | 424 +++++++++++++
 13 files changed, 1917 insertions(+), 9 deletions(-)
 create mode 100644 drivers/acpi/pfr_telemetry.c
 create mode 100644 drivers/acpi/pfr_update.c
 create mode 100644 include/uapi/linux/pfrut.h
 create mode 100644 tools/power/acpi/man/pfrut.8
 create mode 100644 tools/power/acpi/tools/pfrut/Makefile
 create mode 100644 tools/power/acpi/tools/pfrut/pfrut.c

2.25.1

Platform Firmware Runtime Update image starts with UEFI headers, and the headers are defined in UEFI specification, but some of them have not been defined in the kernel yet.

For example, the header layout of a capsule file looks like this:

EFI_CAPSULE_HEADER
EFI_FIRMWARE_MANAGEMENT_CAPSULE_HEADER
EFI_FIRMWARE_MANAGEMENT_CAPSULE_IMAGE_HEADER
EFI_FIRMWARE_IMAGE_AUTHENTICATION

These structures would be used by the Platform Firmware Runtime Update driver to parse the format of capsule file to verify if the corresponding version number is valid. In this way, if the user provides an invalid capsule image, the kernel could be used as a guard to reject it, without switching to the Management Mode (which might be costly).

EFI_CAPSULE_HEADER has been defined in the kernel, but the other structures have not been defined yet, so do that. Besides, EFI_FIRMWARE_MANAGEMENT_CAPSULE_HEADER and EFI_FIRMWARE_MANAGEMENT_CAPSULE_IMAGE_HEADER are required to be packed in the uefi specification. For this reason, use the __packed attribute to indicate to the compiler that the entire structure can appear misaligned in memory (as suggested by Ard) in case one of them follows the other directly in a capsule header.

---
v12:No change since v11.
v11:Add explanation on why version check is introduced
in kernel rather than letting Management Mode to do it.
(Rafael J. Wysocki)
Revise the commit log to better describe the pack attribute. (Rafael J. Wysocki)
Refine the comment for hw_ins and capsule_support.
(Rafael J. Wysocki)
v10:Remove the explicit assignment of the last item of enum.
(Andy Shevchenko)
v9: Use GUID_INIT() instead of guid_parse() during boot up.
(Andy Shevchenko)
Drop uuid, code_uuid, drv_uuid in struct pfru_device as they
are not needed. (Andy Shevchenko)
Drop type casting from void * in valid_version().
(Andy Shevchenko)
Use kfree() instead of ACPI_FREE() in non-ACPICA usage.
(Andy Shevchenko)
Use sizeof(rev) instead of sizeof(u32) in copy_from_user(). (Andy Shevchenko)
Generate physical address from MSB part to LSB.
(Andy Shevchenko)
Use devm_add_action_or_reset() to add ida release into dev resource management. (Andy Shevchenko)
Use devm_kasprintf() instead of kasprintf() to format the pfru_dev name.(Andy Shevchenko)
Remove redundant 0 in acpi_pfru_ids. (Andy Shevchenko)
Adjust the order of included headers in pfru.h.
(Andy Shevchenko)
Replace PFRU_MAGIC with PFRU_MAGIC_FOR_IOCTL in uapi file.
(Andy Shevchenko)
v8: Remove the variable-length array in struct pfru_update_cap_info, and
copy the non-variable-length struct pfru_update_cap_info to userspace directly. (Greg Kroah-Hartman)
Change the type of rev_id from int to u32, because this data will be copied between kernel and userspace. (Greg Kroah-Hartman)
Add a prefix for dev in struct pfru_device to parent_dev, so as to indicate that this filed is the parent of the created miscdev. (Greg Kroah-Hartman)
Use blank lines between different macro sections. (Greg Kroah-Hartman) Illusatrate the possible errno for each ioctl interface.
(Greg Kroah-Hartman)
Remove pfru_valid_revid() from uapi header to avoid poluting the global namespace.(Greg Kroah-Hartman)
Assign the value to the enum type explicitly.(Greg Kroah-Hartman) Change the guid_t to efi_guid_t when parsing image header in get_image_type() (Greg Kroah-Hartman)
Remove the void * to other type casting in valid_version(). (Andy Shevchenko) Combined the assignment of variables with definitions. (Andy Shevchenko) Define this magic for revision ID. (Andy Shevchenko)
Make the labeling consistent for error handling. (Andy Shevchenko) Replace the UUID_SIZE in uapi with 16 directly. (Andy Shevchenko) Add blank line between generic include header and uapi header. (Andy Shevchenko)
Arrange the order between devm_kzalloc() and normal allocation in acpi_pfru_probe() that, the former should always be ahead of the latter. (Andy Shevchenko)
Move the UUID from uapi header to the c file. (Andy Shevchenko)
v7: Use ida_alloc() to allocate a ID, and release the ID when
device is removed. (Greg Kroah-Hartman)
Check the _DSM method at early stage, before allocate or parse anything in acpi_pfru_probe(). (Greg Kroah-Hartman)
Set the parent of the misc device. (Greg Kroah-Hartman)
Use module_platform_driver() instead of platform_driver_register() in module_init(). Separate pfru driver and pfru_telemetry driver to two files. (Greg Kroah-Hartman)
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)

---
 include/linux/efi.h | 46 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

index dbd39b20e034..80e970f7e6f8 100644
@@ -148,6 +148,52 @@ typedef struct {
 	u32 imagesize;
 } efi_capsule_header_t;
 
+/* EFI_FIRMWARE_MANAGEMENT_CAPSULE_HEADER */
+struct efi_manage_capsule_header {
+	u32 ver;
+	u16 emb_drv_cnt;
+	u16 payload_cnt;
+	/*
+	 * Variable-size array of the size given by the sum of
+	 * emb_drv_cnt and payload_cnt.
+	 */
+	u64 offset_list[];
+} __packed;
+
+/* EFI_FIRMWARE_MANAGEMENT_CAPSULE_IMAGE_HEADER */
+struct efi_manage_capsule_image_header {
+	u32 ver;
+	efi_guid_t image_type_id;
+	u8 image_index;
+	u8 reserved_bytes[3];
+	u32 image_size;
+	u32 vendor_code_size;
+	/* hw_ins was introduced in version 2 */
+	u64 hw_ins;
+	/* capsule_support was introduced in version 3 */
+	u64 capsule_support;
+} __packed;
+
+/* WIN_CERTIFICATE */
+struct win_cert {
+	u32 len;
+	u16 rev;
+	u16 cert_type;
+};
+
+/* WIN_CERTIFICATE_UEFI_GUID */
+struct win_cert_uefi_guid {
+	struct win_cert	hdr;
+	efi_guid_t cert_type;
+	u8 cert_data[];
+};
+
+/* EFI_FIRMWARE_IMAGE_AUTHENTICATION */
+struct efi_image_auth {
+	u64 mon_count;
+	struct win_cert_uefi_guid auth_info;
+};
+
 /*
  * EFI capsule flags
  */

2.25.1

Introduce the pfr_update driver which can be used for Platform Firmware Runtime code injection and driver update [1]. The user is expected to provide the EFI capsule, and pass it to the driver by writing the capsule to a device special file. The capsule is transferred by the driver to the platform firmware with the help of an ACPI _DSM method under the special ACPI Platform Firmware Runtime Update device (INTC1080), and the actual firmware update is carried out by the low-level Management Mode code in the platform firmware.

This patch allows certain pieces of the platform firmware to be updated on the fly while the system is running (runtime) without the need to restart it, which is key in the cases when the system needs to be available 100% of the time and it cannot afford the downtime related to restarting it, or when the work carried out by the system is particularly important, so it cannot be interrupted, and it is not practical to wait until it is complete.

---
v12:Rename the driver from pfru_update to pfr_update, and the
telemetry parr to pfr_telementry for symmetry.
(Rafael J. Wysocki)
Rename the "capsule file" to "EFI capsule".
(Rafael J. Wysocki)
Revise the commit log. (Rafael J. Wysocki)
Add the reason in the commit log that explains why it is
a good idea to add this driver to the kernel.
(Rafael J. Wysocki)
Rename pfru.h to pfrut.h (Rafael J. Wysocki)
Rename the CONFIG_ACPI_PFRU to CONFIG_ACPI_PFRUT
(Rafael J. Wysocki)
Rename the Kconfig name to "ACPI Platform Firmware Runtime Update and Telemetry"
(Rafael J. Wysocki)
Revise the Kconfig help message (Rafael J. Wysocki)
Describe what the driver is for briefly in the beginning of
the source code file.
(Rafael J. Wysocki)
Ddd a comment pointing to the definitions of the GUIDs and explain briefly what they are for.
(Rafael J. Wysocki)
Reduce redundant memory updates by doing all of the checks upfront. (Rafael J. Wysocki)
Rename valid_version() to applicable_image(), and revise the comment.(Rafael J. Wysocki)
Remove Redundant else in applicable_image().(Rafael J. Wysocki) Rename dump_update_result() to print_ipdate_debug_info(). (Rafael J. Wysocki)
Rename start_acpi_update() to start_update()(Rafael J. Wysocki) Add a blank line before each "case xxx:"(Rafael J. Wysocki)
Move status check into query_capability() and returns -EBUSY if fails(Rafael J. Wysocki)
Rename the device node name from "acpi_pfru%d" to "acpi_pfr_update%d" (Rafael J. Wysocki)
Rename the drive name from "pfru_update" to "pfr_update"
(Rafael J. Wysocki)
Rename PFRU_MAGIC_FOR_IOCTL to PFRUT_IOCTL_MAGIC(Rafael J. Wysocki) Fix grammar errors in the comments.(Rafael J. Wysocki)
v11:Revise the comment to explain why version check is introduced
in kernel rather than letting Management Mode to do it.
(Rafael J. Wysocki)
v10:Remove the explicit assignment of the last item of enum.
(Andy Shevchenko)
v9: Use GUID_INIT() instead of guid_parse() during boot up.
(Andy Shevchenko)
Drop uuid, code_uuid, drv_uuid in struct pfru_device as they
are not needed. (Andy Shevchenko)
Drop type casting from void * in valid_version().
(Andy Shevchenko)
Use kfree() instead of ACPI_FREE() in non-ACPICA usage.
(Andy Shevchenko)
Use sizeof(rev) instead of sizeof(u32) in copy_from_user(). (Andy Shevchenko)
Generate physical address from MSB part to LSB.
(Andy Shevchenko)
Use devm_add_action_or_reset() to add ida release into dev resource management. (Andy Shevchenko)
Use devm_kasprintf() instead of kasprintf() to format the pfru_dev name.(Andy Shevchenko)
Remove redundant 0 in acpi_pfru_ids. (Andy Shevchenko)
Adjust the order of included headers in pfru.h.
(Andy Shevchenko)
Replace PFRU_MAGIC with PFRU_MAGIC_FOR_IOCTL in uapi file.
(Andy Shevchenko)
v8: Remove the variable-length array in struct pfru_update_cap_info, and
copy the non-variable-length struct pfru_update_cap_info to userspace directly. (Greg Kroah-Hartman)
Change the type of rev_id from int to u32, because this data will be copied between kernel and userspace. (Greg Kroah-Hartman)
Add a prefix for dev in struct pfru_device to parent_dev, so as to indicate that this filed is the parent of the created miscdev. (Greg Kroah-Hartman)
Use blank lines between different macro sections. (Greg Kroah-Hartman) Illusatrate the possible errno for each ioctl interface.
(Greg Kroah-Hartman)
Remove pfru_valid_revid() from uapi header to avoid poluting the global namespace.(Greg Kroah-Hartman)
Assign the value to the enum type explicitly.(Greg Kroah-Hartman) Change the guid_t to efi_guid_t when parsing image header in get_image_type() (Greg Kroah-Hartman)
Remove the void * to other type casting in valid_version(). (Andy Shevchenko) Combined the assignment of variables with definitions. (Andy Shevchenko) Define this magic for revision ID. (Andy Shevchenko)
Make the labeling consistent for error handling. (Andy Shevchenko) Replace the UUID_SIZE in uapi with 16 directly. (Andy Shevchenko) Add blank line between generic include header and uapi header. (Andy Shevchenko)
Arrange the order between devm_kzalloc() and normal allocation in acpi_pfru_probe() that, the former should always be ahead of the latter. (Andy Shevchenko)
Move the UUID from uapi header to the c file. (Andy Shevchenko)
v7: Use ida_alloc() to allocate a ID, and release the ID when
device is removed. (Greg Kroah-Hartman)
Check the _DSM method at early stage, before allocate or parse anything in acpi_pfru_probe(). (Greg Kroah-Hartman)
Set the parent of the misc device. (Greg Kroah-Hartman)
Use module_platform_driver() instead of platform_driver_register() in module_init(). Separate pfru driver and pfru_telemetry driver to two files. (Greg Kroah-Hartman)
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                          |  18 +
 drivers/acpi/Makefile                         |   1 +
 drivers/acpi/pfr_update.c                     | 558 ++++++++++++++++++
 include/uapi/linux/pfrut.h                    | 174 ++++++
 5 files changed, 752 insertions(+)
 create mode 100644 drivers/acpi/pfr_update.c
 create mode 100644 include/uapi/linux/pfrut.h

index cfe6cccf0f44..687efcf245c1 100644
@@ -367,6 +367,7 @@ Code  Seq#    Include File                                           Comments
                                                                      <mailto:[email protected]>
 0xE5  00-3F  linux/fuse.h
 0xEC  00-01  drivers/platform/chrome/cros_ec_dev.h                   ChromeOS EC driver
+0xEE  00-09  uapi/linux/pfrut.h                                      Platform Firmware Runtime Update and Telemetry
 0xF3  00-3F  drivers/usb/misc/sisusbvga/sisusb.h                     sisfb (in development)
                                                                      <mailto:[email protected]>
 0xF6  all                                                            LTTng Linux Trace Toolkit Next Generation

index cdbdf68bd98f..d0b3ca9d4a97 100644
@@ -517,6 +517,24 @@ config ACPI_CONFIGFS
 	  userspace. The configurable ACPI groups will be visible under
 	  /config/acpi, assuming configfs is mounted under /config.
 
+config ACPI_PFRUT
+	tristate "ACPI Platform Firmware Runtime Update and Telemetry"
+	depends on 64BIT
+	help
+	  This mechanism allows certain pieces of the platform firmware
+	  to be updated on the fly while the system is running (runtime)
+	  without the need to restart it, which is key in the cases when
+	  the system needs to be available 100% of the time and it cannot
+	  afford the downtime related to restarting it, or when the work
+	  carried out by the system is particularly important, so it cannot
+	  be interrupted, and it is not practical to wait until it is complete.
+
+	  The existing firmware code can be modified (driver update) or
+	  extended by adding new code to the firmware (code injection).
+
+	  To compile this driver as module, choose M here:
+	  the module will be called pfr_update.
+
 if ARM64
 source "drivers/acpi/arm64/Kconfig"
 

index 3018714e87d9..2ad2e821cc08 100644
@@ -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_PFRUT)	+= pfr_update.o
 
 # processor has its own "processor." module_param namespace
 processor-y			:= processor_driver.o

2.25.1

[cut]

This driver allows user space to fetch telemetry data from the firmware with the help of the Platform Firmware Runtime Telemetry interface.

Both PFRU and PFRT are based on ACPI _DSM interfaces located under special device objects in the ACPI Namespace, but these interfaces are different from each other, so it is better to provide a separate driver from each of them. However, they share some common definitions and naming conventions.

---
v12:Change the subject to "Introduce Platform Firmware Runtime
Telemetry", because there is no "update" part in it.
(Rafael J. Wysocki)
Revise the commit log.(Rafael J. Wysocki)
Move pfr_update.c and pfr_telemetry.c) directly in drivers/acpi/ (Rafael J. Wysocki)
Update Kconfig with the information regarding PFRT
(Rafael J. Wysocki)
Describe the driver briefly at the beginning of the source code (Rafael J. Wysocki)
Replace all PFRU prefix with PFRT.(Rafael J. Wysocki)
Rename pfru_log_device to pfrt_log_device(Rafael J. Wysocki) Rename pfru_log_ida to pfrt_log_ida(Rafael J. Wysocki) Replace pfru with pfrt prefix for all function names. (Rafael J. Wysocki)
Use blank lines to separate the cases visually from each other.(Rafael J. Wysocki)
Replace pfru_telemetry%d with pfrt%d, and acpi_pfru_telemetry%d to acpi_pfr_telemetry.
(Rafael J. Wysocki)
v11:No change since v10.
v10:Remove the explicit assignment of the last item of enum.
(Andy Shevchenko)
v9: Use GUID_INIT() instead of guid_parse() during boot up.
(Andy Shevchenko)
Drop uuid from struct pfru_log_device.(Andy Shevchenko)
Use kfree() instead of ACPI_FREE() in non-ACPICA usage. (Andy Shevchenko)
Use devm_add_action_or_reset() to add ida release into dev resource management. (Andy Shevchenko)
Use devm_kasprintf() instead of kasprintf() to format the pfru_log_dev name.(Andy Shevchenko)
Remove redundant 0 in acpi_pfru_log_ids. (Andy Shevchenko)
v8: Add blank line between generic include header and uapi header.
(Andy Shevchenko)
Arrange the order between devm_kzalloc() and normal allocation in acpi_pfru_log_probe() that, the former should always be ahead of the latter. (Andy Shevchenko)
Amend commit message to elaborate the reason why PFRU and PRFU_Telemetry drivers look the same. (Andy Shevchenko)
v7: Use ida_alloc() to allocate a ID, and release the ID when
device is removed. (Greg Kroah-Hartman)
Check the _DSM method at early stage, before allocate or parse anything in acpi_pfru_log_probe(). (Greg Kroah-Hartman)
Set the parent of the misc device. (Greg Kroah-Hartman)
Use module_platform_driver() instead of platform_driver_register() in module_init(). Separate pfru driver and pfru_telemetry driver to two files. (Greg Kroah-Hartman)
v6: Remove linux/uuid.h and use raw buffers to contain uuid.
(Andy Shevchenko)
Include types.h in pfru.h. (Andy Shevchenko)
Use __u8[16] instead of uuid_t. (Andy Shevchenko)
Replace enum in pfru.h with __u32 as enum size is not the same on all possible architectures.
(Andy Shevchenko)
Directly return results from the switch cases in pfru_log_ioctl(). (Andy Shevchenko)
v5: Remove the log output sample in commit log. (Greg Kroah-Hartman)
Add link for corresponding userspace tool in the commit log. (Greg Kroah-Hartman)
Replace the telemetry .read() with .mmap() so that the userspace could mmap once, and read multiple times. (Greg Kroah-Hartman) Fix the compile warning by declaring the pfru_log_ioctl() as static. (kernel test robot LKP)
v4: 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)
Remove redundant parens. (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: Do similar clean up as pfru_update driver:
Add sanity check for duplicated instance of ACPI device. Update the driver to work with allocated telem_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)

---
 drivers/acpi/Kconfig         |   8 +-
 drivers/acpi/Makefile        |   2 +-
 drivers/acpi/pfr_telemetry.c | 433 +++++++++++++++++++++++++++++++++++
 include/uapi/linux/pfrut.h   |  88 +++++++
 4 files changed, 528 insertions(+), 3 deletions(-)
 create mode 100644 drivers/acpi/pfr_telemetry.c

index d0b3ca9d4a97..91f1da16934d 100644
@@ -532,8 +532,12 @@ config ACPI_PFRUT
 	  The existing firmware code can be modified (driver update) or
 	  extended by adding new code to the firmware (code injection).
 
-	  To compile this driver as module, choose M here:
-	  the module will be called pfr_update.
+	  Besides, the telemetry driver allows user space to fetch telemetry
+	  data from the firmware with the help of the Platform Firmware Runtime
+	  Telemetry interface.
+
+	  To compile the drivers as modules, choose M here:
+	  the modules will be called pfr_update and pfr_telemetry.
 
 if ARM64
 source "drivers/acpi/arm64/Kconfig"

index 2ad2e821cc08..d3dc79298ce3 100644
@@ -102,7 +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-$(CONFIG_ACPI_PFRUT)	+= pfr_update.o
+obj-$(CONFIG_ACPI_PFRUT)	+= pfr_update.o pfr_telemetry.o
 
 # processor has its own "processor." module_param namespace
 processor-y			:= processor_driver.o

2.25.1

Introduce a user space tool to make use of the interface exposed by Platform Firmware Runtime Update and Telemetry drivers. The users can use this tool to do firmware code injection, driver update and to retrieve the telemetry data.

---
v12:Rename tool name from pfru to pfrut, and adjust all
corresponding naming.(Rafael J. Wysocki)
Add what interfaces are used by this tool at the beginning of the source code.
(Rafael J. Wysocki)
v11:No change since v10.
v10:No change since v9.
v9: Add this tool into tools/power/acpi build infrastructure.
(Andy Shevchenko)
v8: Print the length of OEM information if requested.
v7: No change since v6.
v6: Simplify the userspace tool to use while loop for getopt_long().
(Andy Shevchenko)
v5: Replace the read() with mmap() so that the userspace
could mmap once, and read multiple times. (Greg Kroah-Hartman)

---
 tools/power/acpi/.gitignore           |   1 +
 tools/power/acpi/Makefile             |  16 +-
 tools/power/acpi/Makefile.rules       |   2 +-
 tools/power/acpi/man/pfrut.8          | 137 +++++++++
 tools/power/acpi/tools/pfrut/Makefile |  23 ++
 tools/power/acpi/tools/pfrut/pfrut.c  | 424 ++++++++++++++++++++++++++
 6 files changed, 594 insertions(+), 9 deletions(-)
 create mode 100644 tools/power/acpi/man/pfrut.8
 create mode 100644 tools/power/acpi/tools/pfrut/Makefile
 create mode 100644 tools/power/acpi/tools/pfrut/pfrut.c

index 0b319fc8bb17..eada0297ef88 100644
@@ -2,4 +2,5 @@
 /acpidbg
 /acpidump
 /ec
+/pfrut
 /include/

index a249c50ebf55..5ff1d9c864d0 100644
@@ -9,18 +9,18 @@ include ../../scripts/Makefile.include
 
 .NOTPARALLEL:
 
-all: acpidbg acpidump ec
-clean: acpidbg_clean acpidump_clean ec_clean
-install: acpidbg_install acpidump_install ec_install
-uninstall: acpidbg_uninstall acpidump_uninstall ec_uninstall
+all: acpidbg acpidump ec pfrut
+clean: acpidbg_clean acpidump_clean ec_clean pfrut_clean
+install: acpidbg_install acpidump_install ec_install pfrut_install
+uninstall: acpidbg_uninstall acpidump_uninstall ec_uninstall pfrut_uninstall
 
-acpidbg acpidump ec: FORCE
+acpidbg acpidump ec pfrut: FORCE
 	$(call descend,tools/$@,all)
-acpidbg_clean acpidump_clean ec_clean:
+acpidbg_clean acpidump_clean ec_clean pfrut_clean:
 	$(call descend,tools/$(@:_clean=),clean)
-acpidbg_install acpidump_install ec_install:
+acpidbg_install acpidump_install ec_install pfrut_install:
 	$(call descend,tools/$(@:_install=),install)
-acpidbg_uninstall acpidump_uninstall ec_uninstall:
+acpidbg_uninstall acpidump_uninstall ec_uninstall pfrut_uninstall:
 	$(call descend,tools/$(@:_uninstall=),uninstall)
 
 .PHONY: FORCE

index 1d7616f5d0ae..b71aada77688 100644
@@ -9,7 +9,7 @@ objdir := $(OUTPUT)tools/$(TOOL)/
 toolobjs := $(addprefix $(objdir),$(TOOL_OBJS))
 $(OUTPUT)$(TOOL): $(toolobjs) FORCE
 	$(ECHO) "  LD      " $(subst $(OUTPUT),,$@)
-	$(QUIET) $(LD) $(CFLAGS) $(LDFLAGS) $(toolobjs) -L$(OUTPUT) -o $@
+	$(QUIET) $(LD) $(CFLAGS) $(toolobjs) $(LDFLAGS) -L$(OUTPUT) -o $@
 	$(ECHO) "  STRIP   " $(subst $(OUTPUT),,$@)
 	$(QUIET) $(STRIPCMD) $@
 

new file mode 100644
index 000000000000..61c1a96fd433
@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+include ../../Makefile.config
+
+TOOL = pfrut
+EXTRA_INSTALL = install-man
+EXTRA_UNINSTALL = uninstall-man
+
+CFLAGS += -Wall -O2
+CFLAGS += -DPFRUT_HEADER='"../../../../../include/uapi/linux/pfrut.h"'
+LDFLAGS += -luuid
+
+TOOL_OBJS = \
+	pfrut.o
+
+include ../../Makefile.rules
+
+install-man: $(srctree)/man/pfrut.8
+	$(ECHO) "  INST    " pfrut.8
+	$(QUIET) $(INSTALL_DATA) -D $< $(DESTDIR)$(mandir)/man8/pfrut.8
+uninstall-man:
+	$(ECHO) "  UNINST  " pfrut.8
+	$(QUIET) rm -f $(DESTDIR)$(mandir)/man8/pfrut.8

2.25.1