kernel/linux.git/drivers/acpi/pptt.c, branch v6.19.12

ACPI / PPTT: Add a helper to fill a cpumask from a cache_id

2025-11-19T18:34:14+00:00

MPAM identifies CPUs by the cache_id in the PPTT cache structure. The driver needs to know which CPUs are associated with the cache. The CPUs may not all be online, so cacheinfo does not have the information. Add a helper to pull this information out of the PPTT. CC: Rohit Mathew Reviewed-by: Gavin Shan Reviewed-by: Fenghua Yu Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Reviewed-by: Jeremy Linton Tested-by: Fenghua Yu Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Shaopeng Tan Tested-by: Hanjun Guo Signed-off-by: James Morse Signed-off-by: Ben Horgan Signed-off-by: Catalin Marinas

ACPI / PPTT: Find cache level by cache-id

2025-11-19T18:34:09+00:00

The MPAM table identifies caches by id. The MPAM driver also wants to know the cache level to determine if the platform is of the shape that can be managed via resctrl. Cacheinfo has this information, but only for CPUs that are online. Waiting for all CPUs to come online is a problem for platforms where CPUs are brought online late by user-space. Add a helper that walks every possible cache, until it finds the one identified by cache-id, then return the level. Signed-off-by: James Morse Signed-off-by: Ben Horgan Reviewed-by: Gavin Shan Reviewed-by: Fenghua Yu Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Reviewed-by: Jeremy Linton Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Hanjun Guo Signed-off-by: Catalin Marinas

ACPI / PPTT: Add acpi_pptt_cache_v1_full to use pptt cache as one structure

2025-11-19T18:34:01+00:00

In actbl2.h, acpi_pptt_cache describes the fields in the original Cache Type Structure. In PPTT table version 3 a new field was added at the end, cache_id. This is described in acpi_pptt_cache_v1 but rather than including all v1 fields it just includes this one. In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to contain all the fields of the Cache Type Structure . Update the existing code to use this new struct. This simplifies the code and removes a non-standard use of ACPI_ADD_PTR. Reviewed-by: Shaopeng Tan Reviewed-by: Fenghua Yu Reviewed-by: Jonathan Cameron Reviewed-by: Gavin Shan Reviewed-by: Hanjun Guo Reviewed-by: Jeremy Linton Tested-by: Shaopeng Tan Tested-by: Hanjun Guo Signed-off-by: Ben Horgan Signed-off-by: Catalin Marinas

ACPI / PPTT: Stop acpi_count_levels() expecting callers to clear levels

2025-11-19T18:33:56+00:00

In acpi_count_levels(), the initial value of *levels passed by the caller is really an implementation detail of acpi_count_levels(), so it is unreasonable to expect the callers of this function to know what to pass in for this parameter. The only sensible initial value is 0, which is what the only upstream caller (acpi_get_cache_info()) passes. Use a local variable for the starting cache level in acpi_count_levels(), and pass the result back to the caller via the function return value. Get rid of the levels parameter, which has no remaining purpose. Fix acpi_get_cache_info() to match. Suggested-by: Jonathan Cameron Signed-off-by: James Morse Reviewed-by: Lorenzo Pieralisi Reviewed-by: Jonathan Cameron Reviewed-by: Fenghua Yu Reviewed-by: Gavin Shan Reviewed-by: Shaopeng Tan Reviewed-by: Hanjun Guo Reviewed-by: Jeremy Linton Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Hanjun Guo Signed-off-by: Ben Horgan Signed-off-by: Catalin Marinas

ACPI / PPTT: Add a helper to fill a cpumask from a processor container

2025-11-19T18:33:36+00:00

The ACPI MPAM table uses the UID of a processor container specified in the PPTT to indicate the subset of CPUs and cache topology that can access each MPAM System Component (MSC). This information is not directly useful to the kernel. The equivalent cpumask is needed instead. Add a helper to find the processor container by its id, then walk the possible CPUs to fill a cpumask with the CPUs that have this processor container as a parent. CC: Dave Martin Reviewed-by: Sudeep Holla Reviewed-by: Jonathan Cameron Reviewed-by: Fenghua Yu Reviewed-by: Gavin Shan Reviewed-by: Shaopeng Tan Reviewed-by: Hanjun Guo Reviewed-by: Jeremy Linton Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Peter Newman Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Hanjun Guo Signed-off-by: James Morse Signed-off-by: Ben Horgan Signed-off-by: Catalin Marinas

ACPI: PPTT: Fix processor subtable walk

2025-05-08T18:23:16+00:00

The original PPTT code had a bug where the processor subtable length was not correctly validated when encountering a truncated acpi_pptt_processor node. Commit 7ab4f0e37a0f4 ("ACPI PPTT: Fix coding mistakes in a couple of sizeof() calls") attempted to fix this by validating the size is as large as the acpi_pptt_processor node structure. This introduced a regression where the last processor node in the PPTT table is ignored if it doesn't contain any private resources. That results errors like: ACPI PPTT: PPTT table found, but unable to locate core XX (XX) ACPI: SPE must be homogeneous Furthermore, it fails in a common case where the node length isn't equal to the acpi_pptt_processor structure size, leaving the original bug in a modified form. Correct the regression by adjusting the loop termination conditions as suggested by the bug reporters. An additional check performed after the subtable node type is detected, validates the acpi_pptt_processor node is fully contained in the PPTT table. Repeating the check in acpi_pptt_leaf_node() is largely redundant as the node is already known to be fully contained in the table. The case where a final truncated node's parent property is accepted, but the node itself is rejected should not be considered a bug. Fixes: 7ab4f0e37a0f4 ("ACPI PPTT: Fix coding mistakes in a couple of sizeof() calls") Reported-by: Maximilian Heyne Closes: https://lore.kernel.org/linux-acpi/20250506-draco-taped-15f475cd@mheyne-amazon/ Reported-by: Yicong Yang Closes: https://lore.kernel.org/linux-acpi/20250507035124.28071-1-yangyicong@huawei.com/ Signed-off-by: Jeremy Linton Tested-by: Yicong Yang Reviewed-by: Sudeep Holla Tested-by: Maximilian Heyne Cc: All applicable # 7ab4f0e37a0f4: ACPI PPTT: Fix coding mistakes ... Link: https://patch.msgid.link/20250508023025.1301030-1-jeremy.linton@arm.com Signed-off-by: Rafael J. Wysocki

ACPI PPTT: Fix coding mistakes in a couple of sizeof() calls

2025-04-07T18:20:56+00:00

The end of table checks should be done with the structure size, but 2 of the 3 similar calls use the pointer size. Signed-off-by: Jean-Marc Eurin Link: https://patch.msgid.link/20250402001542.2600671-1-jmeurin@google.com [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki

ACPI: PPTT: Fix to avoid sleep in the atomic context when PPTT is absent

2023-03-14T19:34:38+00:00

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 Signed-off-by: Sudeep Holla Tested-by: Pierre Gondois Cc: 6.0+ # 6.0+ Signed-off-by: Rafael J. Wysocki

ACPI: PPTT: Update acpi_find_last_cache_level() to acpi_get_cache_info()

2023-01-18T09:58:40+00:00

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 Signed-off-by: Pierre Gondois Reviewed-by: Jeremy Linton Acked-by: Rafael J. Wysocki Acked-by: Palmer Dabbelt Link: https://lore.kernel.org/r/20230104183033.755668-6-pierre.gondois@arm.com Signed-off-by: Sudeep Holla

ACPI: PPTT: Remove acpi_find_cache_levels()

2023-01-18T09:58:40+00:00

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 Reviewed-by: Jeremy Linton Acked-by: Rafael J. Wysocki Acked-by: Palmer Dabbelt Link: https://lore.kernel.org/r/20230104183033.755668-5-pierre.gondois@arm.com Signed-off-by: Sudeep Holla