| Message ID | 20240419164720.1765-1-shiju.jose@huawei.com |
|---|---|
| Headers | show |
| Series | ras: scrub: introduce subsystem + CXL/ACPI-RAS2 drivers | expand |
On Sat, 20 Apr 2024 00:47:15 +0800 <shiju.jose@huawei.com> wrote: > From: Jonathan Cameron <Jonathan.Cameron@huawei.com> > > Add __free() based cleanup function for acpi_put_table. > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > Signed-off-by: Shiju Jose <shiju.jose@huawei.com> > --- Reviewing (and rejecting) my own patch time ;( I was thinking this would be useful more widely but hadn't looked as closely as I should have done. Sorry Shiju for sending you down a bad path. > include/acpi/acpixf.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h > index 3d90716f9522..fc64d903a703 100644 > --- a/include/acpi/acpixf.h > +++ b/include/acpi/acpixf.h > @@ -492,6 +492,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status > **out_table)) > ACPI_EXTERNAL_RETURN_VOID(void acpi_put_table(struct acpi_table_header *table)) > > +DEFINE_FREE(acpi_put_table, struct acpi_table_header *, if (!IS_ERR_OR_NULL(_T)) acpi_put_table(_T)) This is reliant on acpi_get_table2() in patch 8 / below being used as acpi_get_table() doesn't return the table. Maybe we are better off treating acpi_get_table() / acpi_put_table() as if it were a conditional lock? Or change the 93 instances of acpi_get_table to deal with it returning a copy of the table handle pointer That would bring it inline with many other get functions in the kernel + make our life easier using tooling like this. +static struct acpi_table_header *acpi_get_table2(acpi_string signature, + u32 instance) +{ + struct acpi_table_header *header = NULL; + acpi_status status = acpi_get_table(signature, instance, &header); + + if (ACPI_FAILURE(status)) + return ERR_PTR(-EINVAL); + + return header; +} So that we could do things like: + struct acpi_table_header *pAcpiTable __free(acpi_put_table) = + acpi_get_table2("RAS2", 0); and avoid having to call acpi_put_table() in error paths etc. The snag is that acpi_get_table() is from acpica (via this wrapper) so any modification would be a little messy. Also a number of cases use the status value via const char *msg = acpi_format_exception(status); Which we'd need to return via some path (a parameter probably). We 'could' do that but the advantages of this are getting eroded. Upshot, this is messier than I thought, so we probably shouldn't do it. The code in ras2 can be done reasonably neatly an outer wrapper function that gets the table and an inner one that deals with the actual processing of the entries. Pity as there are some messy bits of code this would tidy up. In most of those a helper function also works. Jonathan p.s. Whilst looking at this I noticed that acpi_has_watchdog() if it succeeds doesn't put the wdat table which seems suspicious as a side effect. > + > ACPI_EXTERNAL_RETURN_STATUS(acpi_status > acpi_get_table_by_index(u32 table_index, > struct acpi_table_header
From: Shiju Jose <shiju.jose@huawei.com> Memory Scrub ============ Increasing DRAM size and cost has made memory subsystem reliability an important concern. These modules are used where potentially corrupted data could cause expensive or fatal issues. Memory errors are one of the top hardware failures that cause server and workload crashes. Memory scrub is a feature where an ECC engine reads data from each memory media location, corrects with an ECC if necessary and writes the corrected data back to the same memory media location. The memory DIMMs could be scrubbed at a configurable rate to detect uncorrected memory errors and attempts to recover from detected memory errors providing the following benefits. - Proactively scrubbing memory DIMMs reduces the chance of a correctable error becoming uncorrectable. - Once detected, uncorrected errors caught in unallocated memory pages are isolated and prevented from being allocated to an application or the OS. - The probability of software/hardware products encountering memory errors is reduced. Some details of background can be found in Reference [5]. There are 2 types of memory scrubbing, 1. Background (patrol) scrubbing of the RAM whilest the RAM is otherwise idle. 2. On-demand scrubbing for a specific address range/region of memory. There are several types of interfaces to HW memory scrubbers identified such as ACPI NVDIMM ARS(Address Range Scrub), CXL memory device patrol scrub, CXL DDR5 ECS, ACPI RAS2 memory scrubbing. The scrub control varies between different memory scrubbers. To allow for standard userspace tooling there is a need to present these controls with a standard ABI. Introduce generic memory scrub subsystem which allows user to control underlying scrubbers in the system via generic sysfs scrub control interface. Use case of scrub control feature ================================= 1. Scrub controls in user space allow the user space tool to disable and enable the feature in case disabling of the scrubbing and changing the scrub rate are needed for other purposes such as performance-aware operations which requires the background operations to be turned off or reduced. 2. Also allows to perform on-demand scrubbing for specific address range if supported by the scrubber. Comparison of scrubbing features ================================ ................................................................ . . ACPI . CXL patrol. CXL ECS . ARS . . Name . RAS2 . scrub . . . ................................................................ . . . . . . . On-demand . Supported . No . No . Supported . . Scrubbing . . . . . . . . . . . ................................................................ . . . . . . . Background . Supported . Supported . Supported . No . . scrubbing . . . . . . . . . . . ................................................................ . . . . . . . Mode of . Scrub ctrl. per device. per memory. Unknown . . scrubbing . per NUMA . . media . . . . domain. . . . . ................................................................ . . . . . . . Query scrub . Supported . Supported . Supported . Supported . . capabilities . . . . . . . . . . . ................................................................ . . . . . . . Setting . Supported . No . No . Supported . . address range. . . . . . . . . . . ................................................................ . . . . . . . Setting . Supported . Supported . No . No . . scrub rate . . . . . . . . . . . ................................................................ . . . . . . . Unit for . Not . in hours . No . No . . scrub rate . Defined . . . . . . . . . . ................................................................ . . Supported . . . . . Scrub . on-demand . No . No . Supported . . status/ . scrubbing . . . . . Completion . only . . . . ................................................................ . UC error . .CXL general.CXL general. ACPI UCE . . reporting . Exception .media/DRAM .media/DRAM . notify and. . . .event/media.event/media. query . . . .scan? .scan? . ARS status. ................................................................ . . . . . . . Clear UC . No . No . No . Supported . . error . . . . . . . . . . . ................................................................ . . . . . . . Translate . No . No . No . Supported . . *(1)SPA to . . . . . . *(2)DPA . . . . . ................................................................ . . . . . . . Error inject . No . Can inject. No . Supported . . . . poison for. . . . . . CXL . . . ................................................................ *(1) - SPA - System Physical Address. See section 9.19.7.8 Function Index 5 - Translate SPA of ACPI spec r6.5. *(2) - DPA - Device Physical Address. See section 9.19.7.8 Function Index 5 - Translate SPA of ACPI spec r6.5. CXL Scrubbing features ====================== Add support for control CXL patrol scrubber and ACPI RAS2 HW based memory patrol scrubber and register with the scrub subsystem to expose the scrub controls to the userspace tool. CXL spec r3.1 section 8.2.9.9.11.1 describes the memory device patrol scrub control feature. The device patrol scrub proactively locates and makes corrections to errors in regular cycle. The patrol scrub control allows the request to configure patrol scrubber's input configurations. The patrol scrub control allows the requester to specify the number of hours in which the patrol scrub cycles must be completed, provided that the requested number is not less than the minimum number of hours for the patrol scrub cycle that the device is capable of. In addition, the patrol scrub controls allow the host to disable and enable the feature in case disabling of the feature is needed for other purposes such as performance-aware operations which require the background operations to be turned off. ACPI RAS2 Hardware-based Memory Scrubbing ========================================= ACPI spec 6.5 section 5.2.21 ACPI RAS2 describes ACPI RAS2 table provides interfaces for platform RAS features and supports independent RAS controls and capabilities for a given RAS feature for multiple instances of the same component in a given system. Memory RAS features apply to RAS capabilities, controls and operations that are specific to memory. RAS2 PCC sub-spaces for memory-specific RAS features have a Feature Type of 0x00 (Memory). The platform can use the hardware-based memory scrubbing feature to expose controls and capabilities associated with hardware-based memory scrub engines. The RAS2 memory scrubbing feature supports following as per spec, - Independent memory scrubbing controls for each NUMA domain, identified using its proximity domain. Note: However AmpereComputing has single entry repeated as they have centralized controls. - Provision for background (patrol) scrubbing of the entire memory system, as well as on-demand scrubbing for a specific region of memory. ACPI Address Range Scrubbing(ARS) ================================ ARS allows the platform to communicate memory errors to system software. This capability allows system software to prevent accesses to addresses with uncorrectable errors in memory. ARS functions manage all NVDIMMs present in the system. Only one scrub can be in progress system wide at any given time. Following functions are supported as per the specification. 1. Query ARS Capabilities for a given address range, indicates platform supports the ACPI NVDIMM Root Device Unconsumed Error Notification. 2. Start ARS triggers an Address Range Scrub for the given memory range. Address scrubbing can be done for volatile memory, persistent memory, or both. 3. Query ARS Status command allows software to get the status of ARS, including the progress of ARS and ARS error record. 4. Clear Uncorrectable Error. 5. Translate SPA 6. ARS Error Inject etc. iNote: Support for ARS is not added in this series because to reduce the line of code for review and could be added after initial code is merged. Series adds, 1. Scrub subsystem driver supports configuring memory scrubbers in the system. 2. Support for CXL feature mailbox commands, which is used by CXL device scrubbing features. 3. CXL device scrub driver supporting patrol scrub control and register with scrub subsystem. 5. ACPI RAS2 driver adds OS interface for RAS2 communication through PCC mailbox and extracts ACPI RAS2 feature table (RAS2) and create platform device for the RAS memory features, which binds to the memory ACPI RAS2 driver. 7. Memory ACPI RAS2 driver gets the PCC subspace for communicating with the ACPI compliant platform supports ACPI RAS2. Add callback functions and registers with scrub subsystem to support user to control the HW patrol scrubbers exposed to the kernel via the ACPI RAS2 table. Note: The RAS2 feature has dependency on the patch "ACPICA: ACPI 6.5: Add support for RAS2 table" which Rafael has queued. https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?h=bleeding-edge&id=9726d821f88e284ecd998b76ae5f2174721cd9dc The QEMU series to support the CXL specific scrub features is available here, https://lore.kernel.org/qemu-devel/20240223085902.1549-1-shiju.jose@huawei.com/ Open Questions based on feedbacks from the community: 1. Leo: Standardize unit for scrub rate, for example ACPI RAS2 does not define unit for the scrub rate. RAS2 clarification needed. 2. Jonathan: May the scrub class to be rename as RASCTL or something like that to allow for wider control options etc that open compute RAS API supports? 3. Jonathan: Any need for discoverability of capability to scan different regions, such as global PA space to the userspace. Left as future extension. 4. Jiaqi: - STOP_PATROL_SCRUBBER from RAS2 must be blocked and, must not be exposed to OS/userspace. Stopping patrol scrubber is unacceptable for platform where OEM has enabled patrol scrubber, because the patrol scrubber is a key part of logging and is repurposed for other RAS actions. If the OEM does not want to expose this control, they should lock it down so the interface is not exposed to the OS. These features are optional afterall. - "Requested Address Range"/"Actual Address Range" (region to scrub) is a similarly bad thing to expose in RAS2. If the OEM does not want to expose this, they should lock it down so the interface is not exposed to the OS. These features are optional afterall. 5. Shiju: How to determine initial status(background scrub / stopped etc). References: 1. ACPI spec r6.5 section 5.2.21 ACPI RAS2. 2. ACPI spec r6.5 section 9.19.7.2 ARS. 3. CXL spec r3.1 8.2.9.9.11.1 Device patrol scrub control feature 4. CXL spec r3.1 8.2.9.9.11.2 DDR5 ECS feature 5. Background information about kernel support for memory scan, memory error detection and ACPI RASF. https://lore.kernel.org/all/20221103155029.2451105-1-jiaqiyan@google.com/ 6. Discussions on RASF: https://lore.kernel.org/lkml/20230915172818.761-1-shiju.jose@huawei.com/#r Changes ======= v7 -> v8: 1. Add more detailed cover letter and add info for basic analysis of ACPI ARS for comment from Dan Williams. 2. Changed file name etc from ras2 to acpi_ras2 in memory ACPI RAS2 driver for comment from Boris. 3. Add documents for usage for comment from Jonathan. 4. Changed logic in memory/acpi_ras2.c for enable background scrubbing to allow setting the scrub rate. 5. Merged memory/acpi_ras2_common.c with memory/acpi_ras2.c and obselete code, suggested by Jonathan. 6. Initial optimizations and cleanup especially in the memory/acpi_ras2. 7. Removed CXL ECS support for time being. 8. Removed support for region based scrub control from the scrub subsytem, which was needed for the CXL ECS, can be added later if required. 9. Fixed the format of few comments and a definition in CXL feature code for the feedbacks from Fan. 11. Jonathan done several optimizations, interface changes and cleanups all over the code. 12. Fixes for feedbacks from Daniel Ferguson(Amperecomputing) for RAS2. 13. Workaround for a RAS2 case of only one actual controller as reported by Daniel Ferguson(AmpereComputing) in their hardware. 14. Feedback from Yazen, move the common scrub and ras2 changes under /drivers/ras/. 15. Drop patch ACPICA: ACPI 6.5: Add support for RAS2 table because Rafael queued the patch. https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?h=bleeding-edge&id=9726d821f88e284ecd998b76ae5f2174721cd9dc v6 -> v7: 1. Main changes for comments from Jonathan, Thanks. 1.1. CXL - Changes for deal with small mail box and supporting multipart feature data transfers. - Provide more specific parameters to mbox supported/get/set features interface functions. - kvmalloc -> kmalloc in CXL scrub mem allocation for feature commands. - Changed the way using __free(kfree) - Removed readback and verify for setting CXL scrub patrol and ECS parameters. Could be added later if needed. - In is_visible() callback functions for scrub control sysfs attrs changed to writeback the default attribute mode value instead of setting per attrs. - Add documentation for sysfs interfaces for CXL ECS scrub control. 1.2. RAS2 - In rasf common code, rename rasf to ras2 because RASF seems obselete. - Replace pr_* with dev_* log function calls from ACPI RAS2 and memory RAS2 drivers. - In rasf common code, rename rasf to ras2. - Removed including unnecessary .h file from memory RAS2 driver. - In is_visible() callback functions for scrub control sysfs attrs changed to writeback the default attribute mode value instead of setting per attribute. 2. Changes for comments from Fan, Thanks. - Add debug message if cxl patrol scrub and ecs init function calls fail. 3. Updated cover letter for feedback from Dan Williams. v5 -> v6: 1. Changes for comments from Davidlohr, Thanks. - Update CXL feature code based on spec 3.1. - attrb -> attr - Use enums with default counting. 2. Rebased to the latest kernel. v4 -> v5: 1. Following are the main changes made based on the feedback from Dan Williams on v4. 1.1. In the scrub subsystem the common scrub control attributes are statically defined instead of dynamically created. 1.2. Add scrub subsystem support externally defined attribute group. Add CXL ECS driver define ECS specific attribute group and pass to the scrub subsystem. 1.3. Move cxl_mem_ecs_init() to cxl/core/region.c so that the CXL region_id is used in the registration with the scrub subsystem. 1.4. Add previously posted RASF common and RAS2 patches to this scrub series. 2. Add support for the 'enable_background_scrub' attribute for RAS2, on request from Bill Schwartz(wschwartz@amperecomputing.com). v3 -> v4: 1. Fixes for the warnings/errors reported by kernel test robot. 2. Add support for reading the 'enable' attribute of CXL patrol scrub. Changes v2 -> v3: 1. Changes for comments from Davidlohr, Thanks. - Updated cxl scrub kconfig - removed usage of the flag is_support_feature from the function cxl_mem_get_supported_feature_entry(). - corrected spelling error. - removed unnecessary debug message. - removed export feature commands to the userspace. 2. Possible fix for the warnings/errors reported by kernel test robot. 3. Add documentation for the common scrub configure atrributes. v1 -> v2: 1. Changes for comments from Dave Jiang, Thanks. - Split patches. - reversed xmas tree declarations. - declared flags as enums. - removed few unnecessary variable initializations. - replaced PTR_ERR_OR_ZERO() with IS_ERR() and PTR_ERR(). - add auto clean declarations. - replaced while loop with for loop. - Removed allocation from cxl_get_supported_features() and cxl_get_feature() and make change to take allocated memory pointer from the caller. - replaced if/else with switch case. - replaced sprintf() with sysfs_emit() in 2 places. - replaced goto label with return in few functions. 2. removed unused code for supported attributes from ecs. 3. Included following common patch for scrub configure driver to this series. "memory: scrub: Add scrub driver supports configuring memory scrubbers in the system" Jonathan Cameron (2): ACPICA: Add __free() based cleanup function for acpi_put_table platform: Add __free() based cleanup function for platform_device_put Shiju Jose (8): ras: scrub: Add scrub subsystem cxl/mbox: Add GET_SUPPORTED_FEATURES mailbox command cxl/mbox: Add GET_FEATURE mailbox command cxl/mbox: Add SET_FEATURE mailbox command cxl/memscrub: Add CXL device patrol scrub control feature ACPI:RAS2: Add ACPI RAS2 driver ras: scrub: Add scrub control attributes for ACPI RAS2 ras: scrub: ACPI RAS2: Add memory ACPI RAS2 driver .../ABI/testing/sysfs-class-scrub-configure | 71 ++++ Documentation/scrub/scrub-configure.rst | 85 ++++ drivers/acpi/Kconfig | 10 + drivers/acpi/Makefile | 1 + drivers/acpi/ras2.c | 366 ++++++++++++++++ drivers/cxl/Kconfig | 19 + drivers/cxl/core/Makefile | 1 + drivers/cxl/core/mbox.c | 153 +++++++ drivers/cxl/core/memscrub.c | 314 ++++++++++++++ drivers/cxl/cxlmem.h | 130 ++++++ drivers/cxl/mem.c | 6 + drivers/ras/Kconfig | 17 + drivers/ras/Makefile | 2 + drivers/ras/acpi_ras2.c | 358 ++++++++++++++++ drivers/ras/memory_scrub.c | 402 ++++++++++++++++++ include/acpi/acpixf.h | 2 + include/acpi/ras2_acpi.h | 59 +++ include/linux/memory_scrub.h | 45 ++ include/linux/platform_device.h | 1 + 19 files changed, 2042 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-scrub-configure create mode 100644 Documentation/scrub/scrub-configure.rst create mode 100755 drivers/acpi/ras2.c create mode 100644 drivers/cxl/core/memscrub.c create mode 100644 drivers/ras/acpi_ras2.c create mode 100755 drivers/ras/memory_scrub.c create mode 100644 include/acpi/ras2_acpi.h create mode 100755 include/linux/memory_scrub.h