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2023-03-14ACPI: PPTT: Fix to avoid sleep in the atomic context when PPTT is absentSudeep Holla1-1/+4
Commit 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage") enabled to map PPTT once on the first invocation of acpi_get_pptt() and never unmapped the same allowing it to be used at runtime with out the hassle of mapping and unmapping the table. This was needed to fetch LLC information from the PPTT in the cpuhotplug path which is executed in the atomic context as the acpi_get_table() might sleep waiting for a mutex. However it missed to handle the case when there is no PPTT on the system which results in acpi_get_pptt() being called from all the secondary CPUs attempting to fetch the LLC information in the atomic context without knowing the absence of PPTT resulting in the splat like below: | BUG: sleeping function called from invalid context at kernel/locking/semaphore.c:164 | in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1 | preempt_count: 1, expected: 0 | RCU nest depth: 0, expected: 0 | no locks held by swapper/1/0. | irq event stamp: 0 | hardirqs last enabled at (0): 0x0 | hardirqs last disabled at (0): copy_process+0x61c/0x1b40 | softirqs last enabled at (0): copy_process+0x61c/0x1b40 | softirqs last disabled at (0): 0x0 | CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.3.0-rc1 #1 | Call trace: | dump_backtrace+0xac/0x138 | show_stack+0x30/0x48 | dump_stack_lvl+0x60/0xb0 | dump_stack+0x18/0x28 | __might_resched+0x160/0x270 | __might_sleep+0x58/0xb0 | down_timeout+0x34/0x98 | acpi_os_wait_semaphore+0x7c/0xc0 | acpi_ut_acquire_mutex+0x58/0x108 | acpi_get_table+0x40/0xe8 | acpi_get_pptt+0x48/0xa0 | acpi_get_cache_info+0x38/0x140 | init_cache_level+0xf4/0x118 | detect_cache_attributes+0x2e4/0x640 | update_siblings_masks+0x3c/0x330 | store_cpu_topology+0x88/0xf0 | secondary_start_kernel+0xd0/0x168 | __secondary_switched+0xb8/0xc0 Update acpi_get_pptt() to consider the fact that PPTT is once checked and is not available on the system and return NULL avoiding any attempts to fetch PPTT and thereby avoiding any possible sleep waiting for a mutex in the atomic context. Fixes: 0c80f9e165f8 ("ACPI: PPTT: Leave the table mapped for the runtime usage") Reported-by: Aishwarya TCV <aishwarya.tcv@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Tested-by: Pierre Gondois <pierre.gondois@arm.com> Cc: 6.0+ <stable@vger.kernel.org> # 6.0+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2023-01-18ACPI: PPTT: Update acpi_find_last_cache_level() to acpi_get_cache_info()Pierre Gondois1-26/+50
acpi_find_last_cache_level() allows to find the last level of cache for a given CPU. The function is only called on arm64 ACPI based platforms to check for cache information that would be missing in the CLIDR_EL1 register. To allow populating (struct cpu_cacheinfo).num_leaves by only parsing a PPTT, update acpi_find_last_cache_level() to get the 'split_levels', i.e. the number of cache levels being split in data/instruction caches. It is assumed that there will not be data/instruction caches above a unified cache. If a split level consist of one data cache and no instruction cache (or opposite), then the missing cache will still be populated by default with minimal cache information, and maximal cpumask (all non-existing caches have the same fw_token). Suggested-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20230104183033.755668-6-pierre.gondois@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2023-01-18ACPI: PPTT: Remove acpi_find_cache_levels()Pierre Gondois1-15/+6
acpi_find_cache_levels() is used at a single place and is short enough to be merged into the calling function. The removal allows an easier renaming of the calling function in the next patch. Also reorder the local variables in the 'reversed Christmas tree' order. Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20230104183033.755668-5-pierre.gondois@arm.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2022-07-22ACPI: PPTT: Leave the table mapped for the runtime usageSudeep Holla1-55/+47
Currently, everytime an information needs to be fetched from the PPTT, the table is mapped via acpi_get_table() and unmapped after the use via acpi_put_table() which is fine. However we do this at runtime especially when the CPU is hotplugged out and plugged in back since we re-populate the cache topology and other information. However, with the support to fetch LLC information from the PPTT in the cpuhotplug path which is executed in the atomic context, it is preferred to avoid mapping and unmapping of the PPTT for every single use as the acpi_get_table() might sleep waiting for a mutex. In order to avoid the same, the table is needs to just mapped once on the boot CPU and is never unmapped allowing it to be used at runtime with out the hassle of mapping and unmapping the table. Reported-by: Guenter Roeck <linux@roeck-us.net> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> -- Hi Rafael, Sorry to bother you again on this PPTT changes. Guenter reported an issue with lockdep enabled in -next that include my cacheinfo/arch_topology changes to utilise LLC from PPTT in the CPU hotplug path. Please ack the change once you are happy so that I can get it merged with other fixes via Greg's tree. Regards, Sudeep Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20220720-arch_topo_fixes-v3-2-43d696288e84@arm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-04ACPI: Remove the unused find_acpi_cpu_cache_topology()Sudeep Holla1-37/+0
The sole user of this find_acpi_cpu_cache_topology() was arm64 topology which is now consolidated into the generic arch_topology without the need of this function. Drop the unused function find_acpi_cpu_cache_topology(). Link: https://lore.kernel.org/r/20220704101605.1318280-22-sudeep.holla@arm.com Cc: Rafael J. Wysocki <rafael@kernel.org> Reported-by: Ionela Voinescu <ionela.voinescu@arm.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2022-07-04ACPI: PPTT: Use table offset as fw_token instead of virtual addressSudeep Holla1-1/+2
There is need to use the cache sharing information quite early during the boot before the secondary cores are up and running. The permanent memory map for all the ACPI tables(via acpi_permanent_mmap) is turned on in acpi_early_init() which is quite late for the above requirement. As a result there is possibility that the ACPI PPTT gets mapped to different virtual addresses. In such scenarios, using virtual address as fw_token before the acpi_permanent_mmap is enabled results in different fw_token for the same cache entity and hence wrong cache sharing information will be deduced based on the same. Instead of using virtual address, just use the table offset as the unique firmware token for the caches. The same offset is used as ACPI identifiers if the firmware has not set a valid one for other entries in the ACPI PPTT. Link: https://lore.kernel.org/r/20220704101605.1318280-2-sudeep.holla@arm.com Cc: linux-acpi@vger.kernel.org Tested-by: Ionela Voinescu <ionela.voinescu@arm.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2021-10-15topology: Represent clusters of CPUs within a dieJonathan Cameron1-0/+67
Both ACPI and DT provide the ability to describe additional layers of topology between that of individual cores and higher level constructs such as the level at which the last level cache is shared. In ACPI this can be represented in PPTT as a Processor Hierarchy Node Structure [1] that is the parent of the CPU cores and in turn has a parent Processor Hierarchy Nodes Structure representing a higher level of topology. For example Kunpeng 920 has 6 or 8 clusters in each NUMA node, and each cluster has 4 cpus. All clusters share L3 cache data, but each cluster has local L3 tag. On the other hand, each clusters will share some internal system bus. +-----------------------------------+ +---------+ | +------+ +------+ +--------------------------+ | | | CPU0 | | cpu1 | | +-----------+ | | | +------+ +------+ | | | | | | +----+ L3 | | | | +------+ +------+ cluster | | tag | | | | | CPU2 | | CPU3 | | | | | | | +------+ +------+ | +-----------+ | | | | | | +-----------------------------------+ | | +-----------------------------------+ | | | +------+ +------+ +--------------------------+ | | | | | | | +-----------+ | | | +------+ +------+ | | | | | | | | L3 | | | | +------+ +------+ +----+ tag | | | | | | | | | | | | | | +------+ +------+ | +-----------+ | | | | | | +-----------------------------------+ | L3 | | data | +-----------------------------------+ | | | +------+ +------+ | +-----------+ | | | | | | | | | | | | | +------+ +------+ +----+ L3 | | | | | | tag | | | | +------+ +------+ | | | | | | | | | | | +-----------+ | | | +------+ +------+ +--------------------------+ | +-----------------------------------| | | +-----------------------------------| | | | +------+ +------+ +--------------------------+ | | | | | | | +-----------+ | | | +------+ +------+ | | | | | | +----+ L3 | | | | +------+ +------+ | | tag | | | | | | | | | | | | | | +------+ +------+ | +-----------+ | | | | | | +-----------------------------------+ | | +-----------------------------------+ | | | +------+ +------+ +--------------------------+ | | | | | | | +-----------+ | | | +------+ +------+ | | | | | | | | L3 | | | | +------+ +------+ +---+ tag | | | | | | | | | | | | | | +------+ +------+ | +-----------+ | | | | | | +-----------------------------------+ | | +-----------------------------------+ | | | +------+ +------+ +--------------------------+ | | | | | | | +-----------+ | | | +------+ +------+ | | | | | | | | L3 | | | | +------+ +------+ +--+ tag | | | | | | | | | | | | | | +------+ +------+ | +-----------+ | | | | +---------+ +-----------------------------------+ That means spreading tasks among clusters will bring more bandwidth while packing tasks within one cluster will lead to smaller cache synchronization latency. So both kernel and userspace will have a chance to leverage this topology to deploy tasks accordingly to achieve either smaller cache latency within one cluster or an even distribution of load among clusters for higher throughput. This patch exposes cluster topology to both kernel and userspace. Libraried like hwloc will know cluster by cluster_cpus and related sysfs attributes. PoC of HWLOC support at [2]. Note this patch only handle the ACPI case. Special consideration is needed for SMT processors, where it is necessary to move 2 levels up the hierarchy from the leaf nodes (thus skipping the processor core level). Note that arm64 / ACPI does not provide any means of identifying a die level in the topology but that may be unrelate to the cluster level. [1] ACPI Specification 6.3 - section 5.2.29.1 processor hierarchy node structure (Type 0) [2] https://github.com/hisilicon/hwloc/tree/linux-cluster Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Tian Tao <tiantao6@hisilicon.com> Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210924085104.44806-2-21cnbao@gmail.com
2021-06-07ACPI: tables: PPTT: Populate cache-id if provided by firmwareJames Morse1-4/+14
ACPI 6.4 adds a 'cache id' to the PPTT Cache Type Structure. Copy this property across into the cacheinfo leaf when it was provided by firmware. This value gets exposed to userspace as: /sys/devices/system/cpu/cpu*/cache/index*/id. See the "Cache IDs" section of Documentation/x86/resctrl.rst. Co-authored-by: Joey Gouly <joey.gouly@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Joey Gouly <joey.gouly@arm.com> [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-01-07ACPI: PPTT: Consistently use unsigned int as parameter typeTian Tao1-14/+15
The fourth parameter 'level' of function 'acpi_find_cache_level()' is a signed interger, but its caller 'acpi_find_cache_node()' passes that parameter an unsigned interger. Make the paramter type inconsistency go away. Signed-off-by: Tian Tao <tiantao6@huawei.com> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> [ rjw: Subject/changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-08-12ACPI/PPTT: Add support for ACPI 6.3 thread flagJeremy Linton1-1/+52
ACPI 6.3 adds a flag to the CPU node to indicate whether the given PE is a thread. Add a function to return that information for a given linux logical CPU. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Robert Richter <rrichter@marvell.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-06-27ACPI/PPTT: Add function to return ACPI 6.3 Identical tokensJeremy Linton1-0/+26
ACPI 6.3 adds a flag to indicate that child nodes are all identical cores. This is useful to authoritatively determine if a set of (possibly offline) cores are identical or not. Since the flag doesn't give us a unique id we can generate one and use it to create bitmaps of sibling nodes, or simply in a loop to determine if a subset of cores are identical. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-06-27ACPI/PPTT: Modify node flag detection to find last IDENTICALJeremy Linton1-6/+29
The ACPI specification implies that the IDENTICAL flag should be set on all non leaf nodes where the children are identical. This means that we need to be searching for the last node with the identical flag set rather than the first one. Since this flag is also dependent on the table revision, we need to add a bit of extra code to verify the table revision, and the next node's state in the traversal. Since we want to avoid function pointers here, lets just special case the IDENTICAL flag. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-03-27ACPI: Fix comment typosBjorn Helgaas1-24/+24
Fix some misspellings in comments. No functional change intended. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-03-11ACPI: tables: Simplify PPTT leaf node detectionJeremy Linton1-0/+3
ACPI 6.3 bumps the PPTT table revision and adds a LEAF_NODE flag. This allows us to avoid a second pass through the table to assure that the node in question is a leaf. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-08ACPI/PPTT: Add acpi_pptt_warn_missing() to consolidate logsJohn Garry1-4/+9
For a system using ACPI-based FW without a PPTT, we may get many warnings about the lack of a PPTT, as shown: root@(none)$ dmesg | grep -i pptt [ 0.010125] ACPI PPTT: No PPTT table found, cpu topology may be inaccurate [ 7.138339] ACPI PPTT: No PPTT table found, cache topology may be inaccurate [ 7.145368] ACPI PPTT: No PPTT table found, cache topology may be inaccurate These logs are generated with pr_warn_once(), so the intention was for a single log, but the logs overlap, so consolidate them. Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-10-05ACPI/PPTT: Handle architecturally unknown cache typesJeffrey Hugo1-20/+13
The type of a cache might not be specified by architectural mechanisms (ie system registers), but its type might be specified in the PPTT. In this case, we should populate the type of the cache, rather than leave it undefined. This fixes the issue where the cacheinfo driver will not populate sysfs for such caches, resulting in the information missing from utilities like lstopo and lscpu, thus degrading the user experience. Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing) Reported-by: Vijaya Kumar K <vkilari@codeaurora.org> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-02ACPI / PPTT: use ACPI ID whenever ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is setSudeep Holla1-2/+8
Currently, we use the ACPI processor ID only for the leaf/processor nodes as the specification states it must match the value of the ACPI processor ID field in the processor’s entry in the MADT. However, if a PPTT structure represents a processors group, it matches a processor container UID in the namespace and the ACPI_PPTT_ACPI_PROCESSOR_ID_VALID flag indicates whether the ACPI processor ID is valid. Let's use UID whenever ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set to be consistent instead of using table offset as it's currently done for non-leaf nodes. Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing) Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Jeremy Linton <jeremy.linton@arm.com> [ rjw: Changelog (minor) ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-17ACPI/PPTT: Add Processor Properties Topology Table parsingJeremy Linton1-0/+655
ACPI 6.2 adds a new table, which describes how processing units are related to each other in tree like fashion. Caches are also sprinkled throughout the tree and describe the properties of the caches in relation to other caches and processing units. Add the code to parse the cache hierarchy and report the total number of levels of cache for a given core using acpi_find_last_cache_level() as well as fill out the individual cores cache information with cache_setup_acpi() once the cpu_cacheinfo structure has been populated by the arch specific code. An additional patch later in the set adds the ability to report peers in the topology using find_acpi_cpu_topology() to report a unique ID for each processing unit at a given level in the tree. These unique id's can then be used to match related processing units which exist as threads, within a given package, etc. Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Vijaya Kumar K <vkilari@codeaurora.org> Tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Tested-by: Tomasz Nowicki <Tomasz.Nowicki@cavium.com> Acked-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>