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path: root/drivers/base/cacheinfo.c
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2019-01-22cacheinfo: Keep the old value if of_property_read_u32 failsHuacai Chen
Commit 448a5a552f336bd7b847b1951 ("drivers: base: cacheinfo: use OF property_read_u32 instead of get_property,read_number") makes cache size and number_of_sets be 0 if DT doesn't provide there values. I think this is unreasonable so make them keep the old values, which is the same as old kernels. Fixes: 448a5a552f33 ("drivers: base: cacheinfo: use OF property_read_u32 instead of get_property,read_number") Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen <chenhc@lemote.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-04drivers: base: cacheinfo: Do not populate sysfs for unknown cache typesJeffrey Hugo
If a cache has an unknown type because neither the hardware nor the firmware told us, an entry in the sysfs tree will be made, but the type file will not be present. lscpu depends on the type file being present for every entry, and will error out without printing system information if lscpu cannot open the type file. Presenting information about a cache without indicating its type is not useful, therefore if we hit a cache with an unknown type, stop populating sysfs so that userspace has the maximum amount of useful information. This addresses the following lscpu error, which prevents any output. lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such file or directory Suggested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-07-07drivers: base: cacheinfo: use OF property_read_u32 instead of ↵Sudeep Holla
get_property,read_number of_property_read_u32 searches for a property in a device node and read a 32-bit value from it. Instead of using of_get_property to get the property and then read 32-bit value using of_read_number, we can simplify it by using of_property_read_u32. Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-17drivers: base cacheinfo: Add support for ACPI based firmware tablesJeremy Linton
Call ACPI cache parsing routines from base cacheinfo code if ACPI is enabled. Also stub out cache_setup_acpi and acpi_find_last_cache_level so that individual architectures can enable ACPI topology parsing. 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-05-17cacheinfo: rename of_node to fw_tokenJeremy Linton
Rename and change the type of of_node to indicate it is a generic pointer which is generally only used for comparison purposes. In a later patch we will put an ACPI/PPTT token pointer in fw_token so that the code which builds the shared cpu masks can be reused. 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-05-17drivers: base: cacheinfo: setup DT cache properties earlyJeremy Linton
The original intent in cacheinfo was that an architecture specific populate_cache_leaves() would probe the hardware and then cache_shared_cpu_map_setup() and cache_override_properties() would provide firmware help to extend/expand upon what was probed. Arm64 was really the only architecture that was working this way, and with the removal of most of the hardware probing logic it became clear that it was possible to simplify the logic a bit. This patch combines the walk of the DT nodes with the code updating the cache size/line_size and nr_sets. cache_override_properties() (which was DT specific) is then removed. The result is that cacheinfo.of_node is no longer used as a temporary place to hold DT references for future calls that update cache properties. That change helps to clarify its one remaining use (matching cacheinfo nodes that represent shared caches) which will be used by the ACPI/PPTT code in the following patches. 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-05-17drivers: base: cacheinfo: move cache_setup_of_node()Jeremy Linton
In preparation for the next patch, and to aid in review of that patch, lets move cache_setup_of_node further down in the module without any changes. 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> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-01-02Merge 4.15-rc6 into driver-core-nextGreg Kroah-Hartman
We want the fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-15drivers: base: cacheinfo: fix cache type for non-architected system cacheSudeep Holla
Commit dfea747d2aba ("drivers: base: cacheinfo: support DT overrides for cache properties") doesn't initialise the cache type if it's present only in DT and the architecture is not aware of it. They are unified system level cache which are generally transparent. This patch check if the cache type is set to NOCACHE but the DT node indicates that it's unified cache and sets the cache type accordingly. Fixes: dfea747d2aba ("drivers: base: cacheinfo: support DT overrides for cache properties") Reported-and-tested-by: Tan Xiaojun <tanxiaojun@huawei.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-07driver core: Remove redundant license textGreg Kroah-Hartman
Now that the SPDX tag is in all driver core files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-07driver core: add SPDX identifiers to all driver core filesGreg Kroah-Hartman
It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the driver core files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Johannes Berg <johannes@sipsolutions.net> Cc: "Luis R. Rodriguez" <mcgrof@kernel.org> Cc: William Breathitt Gray <vilhelm.gray@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-12-22Merge branch 'x86-cache-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cache allocation interface from Thomas Gleixner: "This provides support for Intel's Cache Allocation Technology, a cache partitioning mechanism. The interface is odd, but the hardware interface of that CAT stuff is odd as well. We tried hard to come up with an abstraction, but that only allows rather simple partitioning, but no way of sharing and dealing with the per package nature of this mechanism. In the end we decided to expose the allocation bitmaps directly so all combinations of the hardware can be utilized. There are two ways of associating a cache partition: - Task A task can be added to a resource group. It uses the cache partition associated to the group. - CPU All tasks which are not member of a resource group use the group to which the CPU they are running on is associated with. That allows for simple CPU based partitioning schemes. The main expected user sare: - Virtualization so a VM can only trash only the associated part of the cash w/o disturbing others - Real-Time systems to seperate RT and general workloads. - Latency sensitive enterprise workloads - In theory this also can be used to protect against cache side channel attacks" [ Intel RDT is "Resource Director Technology". The interface really is rather odd and very specific, which delayed this pull request while I was thinking about it. The pull request itself came in early during the merge window, I just delayed it until things had calmed down and I had more time. But people tell me they'll use this, and the good news is that it is _so_ specific that it's rather independent of anything else, and no user is going to depend on the interface since it's pretty rare. So if push comes to shove, we can just remove the interface and nothing will break ] * 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) x86/intel_rdt: Implement show_options() for resctrlfs x86/intel_rdt: Call intel_rdt_sched_in() with preemption disabled x86/intel_rdt: Update task closid immediately on CPU in rmdir and unmount x86/intel_rdt: Fix setting of closid when adding CPUs to a group x86/intel_rdt: Update percpu closid immeditately on CPUs affected by changee x86/intel_rdt: Reset per cpu closids on unmount x86/intel_rdt: Select KERNFS when enabling INTEL_RDT_A x86/intel_rdt: Prevent deadlock against hotplug lock x86/intel_rdt: Protect info directory from removal x86/intel_rdt: Add info files to Documentation x86/intel_rdt: Export the minimum number of set mask bits in sysfs x86/intel_rdt: Propagate error in rdt_mount() properly x86/intel_rdt: Add a missing #include MAINTAINERS: Add maintainer for Intel RDT resource allocation x86/intel_rdt: Add scheduler hook x86/intel_rdt: Add schemata file x86/intel_rdt: Add tasks files x86/intel_rdt: Add cpus file x86/intel_rdt: Add mkdir to resctrl file system x86/intel_rdt: Add "info" files to resctrl file system ...
2016-12-13Merge tag 'driver-core-4.10-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here's the new driver core patches for 4.10-rc1. Big thing here is the nice addition of "functional dependencies" to the driver core. The idea has been talked about for a very long time, great job to Rafael for stepping up and implementing it. It's been tested for longer than the 4.9-rc1 date, we held off on merging it earlier in order to feel more comfortable about it. Other than that, it's just a handful of small other patches, some good cleanups to the mess that is the firmware class code, and we have a test driver for the deferred probe logic. All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (30 commits) firmware: Correct handling of fw_state_wait() return value driver core: Silence device links sphinx warning firmware: remove warning at documentation generation time drivers: base: dma-mapping: Fix typo in dmam_alloc_non_coherent comments driver core: test_async: fix up typo found by 0-day firmware: move fw_state_is_done() into UHM section firmware: do not use fw_lock for fw_state protection firmware: drop bit ops in favor of simple state machine firmware: refactor loading status firmware: fix usermode helper fallback loading driver core: firmware_class: convert to use class_groups driver core: devcoredump: convert to use class_groups driver core: class: add class_groups support kernfs: Declare two local data structures static driver-core: fix platform_no_drv_owner.cocci warnings drivers/base/memory.c: Remove unused 'first_page' variable driver core: add CLASS_ATTR_WO() drivers: base: cacheinfo: support DT overrides for cache properties drivers: base: cacheinfo: add pr_fmt logging drivers: base: cacheinfo: fix boot error message when acpi is enabled ...
2016-11-10drivers: base: cacheinfo: support DT overrides for cache propertiesSudeep Holla
Few architectures like x86, ia64 and s390 derive the cache topology and all the properties using a specific architected mechanism while some other architectures like powerpc all those information id derived from the device tree. On ARM, both the mechanism is used. While all the cache properties can be derived in a architected way, it needs to rely on device tree to get the cache topology information. However there are few platforms where this architected mechanism is broken and the device tree properties can be used to override these incorrect values. This patch adds support for overriding the cache properties values to the values specified in the device tree. Cc: Alex Van Brunt <avanbrunt@nvidia.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-10drivers: base: cacheinfo: add pr_fmt loggingSudeep Holla
This cleanup patch just adds pr_fmt style logging for cacheinfo. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-10drivers: base: cacheinfo: fix boot error message when acpi is enabledSudeep Holla
ARM64 enables both CONFIG_OF and CONFIG_ACPI and the firmware can pass both ACPI tables and the device tree. Based on the kernel parameter, one of the two will be chosen. If acpi is enabled, then device tree is not unflattened. Currently ARM64 platforms report: " Failed to find cpu0 device node Unable to detect cache hierarchy from DT for CPU 0 " which is incorrect when booting with ACPI. Also latest ACPI v6.1 has no support for cache properties/hierarchy. This patch adds check for unflattened device tree and also returns as "not supported" if ACPI is runtime enabled. It also removes the reference to DT from the error message as the cache hierarchy can be detected from the firmware(OF/DT/ACPI) Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-10drivers: base: cacheinfo: fix x86 with CONFIG_OF enabledSudeep Holla
With CONFIG_OF enabled on x86, we get the following error on boot: " Failed to find cpu0 device node Unable to detect cache hierarchy from DT for CPU 0 " and the cacheinfo fails to get populated in the corresponding sysfs entries. This is because cache_setup_of_node looks for of_node for setting up the shared cpu_map without checking that it's already populated in the architecture specific callback. In order to indicate that the shared cpu_map is already populated, this patch introduces a boolean `cpu_map_populated` in struct cpu_cacheinfo that can be used by the generic code to skip cache_shared_cpu_map_setup. This patch also sets that boolean for x86. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-11-09drivers base/cacheinfo: Convert to hotplug state machineSebastian Andrzej Siewior
Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. No functional change. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20161103145021.28528-13-bigeasy@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-10-26cacheinfo: Introduce cache idFenghua Yu
Cache management software needs an id for each instance of a cache of a particular type. The current cacheinfo structure does not provide any information about the underlying hardware so there is no way to expose it. Hardware with cache management features provides means (cpuid, enumeration etc.) to retrieve the hardware id of a particular cache instance. Cache instances which share hardware have the same hardware id. Add an 'id' field to struct cacheinfo to store this information. Expose this information under the /sys/devices/system/cpu/cpu*/cache/index*/ directory as well. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477142405-32078-3-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-17cpu/cacheinfo: Fix teardown pathBorislav Petkov
Philip Müller reported a hang when booting 32-bit 4.1 kernel on an AMD box. A fragment of the splat was enough to pinpoint the issue: task: f58e0000 ti: f58e8000 task.ti: f58e800 EIP: 0060:[<c135a903>] EFLAGS: 00010206 CPU: 0 EIP is at free_cache_attributes+0x83/0xd0 EAX: 00000001 EBX: f589d46c ECX: 00000090 EDX: 360c2000 ESI: 00000000 EDI: c1724a80 EBP: f58e9ec0 ESP: f58e9ea0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 000000ac CR3: 01731000 CR4: 000006d0 cache_shared_cpu_map_setup() did check sibling CPUs cacheinfo descriptor while the respective teardown path cache_shared_cpu_map_remove() didn't. Fix that. >From tglx's version: to be on the safe side, move the cacheinfo descriptor check to free_cache_attributes(), thus cleaning up the hotplug path a little and making this even more robust. Reported-and-tested-by: Philip Müller <philm@manjaro.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Sudeep Holla <sudeep.holla@arm.com> Cc: <stable@vger.kernel.org> # 4.1 Cc: Andre Przywara <andre.przywara@arm.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-kernel@vger.kernel.org Cc: manjaro-dev@manjaro.org Cc: Philip Müller <philm@manjaro.org> Link: https://lkml.kernel.org/r/55B47BB8.6080202@manjaro.org Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-06-08Merge 4.1-rc7 into driver-core-nextGreg Kroah-Hartman
We want the fixes in this branch as well for testing and merge resolution. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-06-01drivers/base: cacheinfo: handle absence of cachesSudeep Holla
On some simulators like GEM5, caches may not be simulated. In those cases, the cache levels and leaves will be zero and will result in following exception: Unable to handle kernel NULL pointer dereference at virtual address 0040 pgd = ffffffc0008fa000 [00000040] *pgd=00000009f6807003, *pud=00000009f6807003, *pmd=00000009f6808003, *pte=006000002c010707 Internal error: Oops: 96000005 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.1.0-rc5 #198 task: ffffffc9768a0000 ti: ffffffc9768a8000 task.ti: ffffffc9768a8000 PC is at detect_cache_attributes+0x98/0x2c8 LR is at detect_cache_attributes+0x88/0x2c8 kcalloc(0) returns a special value ZERO_SIZE_PTR which is non-NULL value but results in fault only on any attempt to dereferencing it. So checking for the non-NULL pointer will not suffice. This patch checks for non-zero cache leaf nodes and returns error if there are no cache leaves in detect_cache_attributes. Cc: <stable@vger.kernel.org> # 3.19.x Cc: Will Deacon <will.deacon@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reported-by: William Wang <william.wang@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-24drivers/base: cacheinfo: fix annoying typo when DT nodes are absentWill Deacon
s/hierarcy/hierarchy/ Maybe the typo will annoy people enough so that they add the missing nodes to their device-tree files, but I still think this is better off fixed. Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-25drivers/base: cacheinfo: validate device node for all the cachesSudeep Holla
On architectures that depend on DT for obtaining cache hierarcy, we need to validate the device node for all the cache indices, failing to do so might result in wrong information being exposed to the userspace. This is quite possible on initial/incomplete versions of the device trees. In such cases, it's better to bail out if all the required device nodes are not present. This patch adds checks for the validation of device node for all the caches and doesn't initialise the cacheinfo if there's any error. Reported-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Cc: stable <stable@vger.kernel.org> # 4.0 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-24drivers/base: cacheinfo: remove noisy error boot messageSudeep Holla
On systems that don't support cacheinfo, this error message can be considered noisy and irrelevant. The error messages can be added to the functions that architectures implement overiding the weak default definition if really required. This patch removes the concerned error message in the generic code. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Reported-by: Fabio Estevam <festevam@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-07drivers: base: support cpu cache information interface to userspace via sysfsSudeep Holla
This patch adds initial support for providing processor cache information to userspace through sysfs interface. This is based on already existing implementations(x86, ia64, s390 and powerpc) and hence the interface is intended to be fully compatible. The main purpose of this generic support is to avoid further code duplication to support new architectures and also to unify all the existing different implementations. This implementation maintains the hierarchy of cache objects which reflects the system's cache topology. Cache devices are instantiated as needed as CPUs come online. The cache information is replicated per-cpu even if they are shared. A per-cpu array of cache information maintained is used mainly for sysfs-related book keeping. It also implements the shared_cpu_map attribute, which is essential for enabling both kernel and user-space to discover the system's overall cache topology. This patch also add the missing ABI documentation for the cacheinfo sysfs interface already, which is well defined and widely used. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Tested-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-api@vger.kernel.org Cc: linux390@de.ibm.com Cc: linux-arm-kernel@lists.infradead.org Cc: linux-ia64@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Cc: x86@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>