kernel/linux.git/drivers/base/topology.c, branch v6.19.11

sysfs: treewide: switch back to attribute_group::bin_attrs

2025-06-17T08:44:15+00:00

The normal bin_attrs field can now handle const pointers. This makes the _new variant unnecessary. Switch all users back. Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-4-724bfcf05b99@weissschuh.net Signed-off-by: Greg Kroah-Hartman

arch_topology: Relocate cpu_scale to topology.[h|c]

2025-05-07T19:56:55+00:00

arch_topology.c provides functionality to parse and scale CPU capacity. It also provides a corresponding sysfs interface. Some architectures parse and scale CPU capacity differently as per their own needs. On Intel processors, for instance, it is responsibility of the Intel P-state driver. Relocate the implementation of that interface to a common location in topology.c. Architectures can use the interface and populate it using their own mechanisms. An alternative approach would be to compile arch_topology.c even if not needed only to get this interface. This approach would create duplicated and conflicting functionality and data structures. Signed-off-by: Ricardo Neri Tested-by: Christian Loehle Link: https://patch.msgid.link/20250419025504.9760-2-ricardo.neri-calderon@linux.intel.com Signed-off-by: Rafael J. Wysocki

topology: Keep the cpumask unchanged when printing cpumap

2025-01-07T16:58:08+00:00

During fuzz testing, the following warning was discovered: different return values (15 and 11) from vsnprintf("%*pbl ", ...) test:keyward is WARNING in kvasprintf WARNING: CPU: 55 PID: 1168477 at lib/kasprintf.c:30 kvasprintf+0x121/0x130 Call Trace: kvasprintf+0x121/0x130 kasprintf+0xa6/0xe0 bitmap_print_to_buf+0x89/0x100 core_siblings_list_read+0x7e/0xb0 kernfs_file_read_iter+0x15b/0x270 new_sync_read+0x153/0x260 vfs_read+0x215/0x290 ksys_read+0xb9/0x160 do_syscall_64+0x56/0x100 entry_SYSCALL_64_after_hwframe+0x78/0xe2 The call trace shows that kvasprintf() reported this warning during the printing of core_siblings_list. kvasprintf() has several steps: (1) First, calculate the length of the resulting formatted string. (2) Allocate a buffer based on the returned length. (3) Then, perform the actual string formatting. (4) Check whether the lengths of the formatted strings returned in steps (1) and (2) are consistent. If the core_cpumask is modified between steps (1) and (3), the lengths obtained in these two steps may not match. Indeed our test includes cpu hotplugging, which should modify core_cpumask while printing. To fix this issue, cache the cpumask into a temporary variable before calling cpumap_print_{list, cpumask}_to_buf(), to keep it unchanged during the printing process. Fixes: bb9ec13d156e ("topology: use bin_attribute to break the size limitation of cpumap ABI") Cc: stable Signed-off-by: Li Huafei Reviewed-by: Jonathan Cameron Link: https://lore.kernel.org/r/20241114110141.94725-1-lihuafei1@huawei.com Signed-off-by: Greg Kroah-Hartman

driver core: Constify bin_attribute definitions

2024-11-15T18:29:16+00:00

Mark all 'struct bin_attribute' instances as const to protect against accidental and malicious modifications. Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/r/20241115-b4-sysfs-const-bin_attr-group-v1-2-2c9bb12dfc48@weissschuh.net Signed-off-by: Greg Kroah-Hartman

driver core: Constify attribute arguments of binary attributes

2024-11-05T13:00:28+00:00

As preparation for the constification of struct bin_attribute, constify the arguments of the read and write callbacks. Signed-off-by: Thomas Weißschuh Acked-by: Krzysztof Wilczyński Link: https://lore.kernel.org/r/20241103-sysfs-const-bin_attr-v2-10-71110628844c@weissschuh.net Signed-off-by: Greg Kroah-Hartman

drivers/base: fix userspace break from using bin_attributes for cpumap and cpulist

2022-07-15T15:36:33+00:00

Using bin_attributes with a 0 size causes fstat and friends to return that 0 size. This breaks userspace code that retrieves the size before reading the file. Rather than reverting 75bd50fa841 ("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") let's put in a size value at compile time. For cpulist the maximum size is on the order of NR_CPUS * (ceil(log10(NR_CPUS)) + 1)/2 which for 8192 is 20480 (8192 * 5)/2. In order to get near that you'd need a system with every other CPU on one node. For example: (0,2,4,8, ... ). To simplify the math and support larger NR_CPUS in the future we are using (NR_CPUS * 7)/2. We also set it to a min of PAGE_SIZE to retain the older behavior for smaller NR_CPUS. The cpumap file the size works out to be NR_CPUS/4 + NR_CPUS/32 - 1 (or NR_CPUS * 9/32 - 1) including the ","s. Add a set of macros for these values to cpumask.h so they can be used in multiple places. Apply these to the handful of such files in drivers/base/topology.c as well as node.c. As an example, on an 80 cpu 4-node system (NR_CPUS == 8192): before: -r--r--r--. 1 root root 0 Jul 12 14:08 system/node/node0/cpulist -r--r--r--. 1 root root 0 Jul 11 17:25 system/node/node0/cpumap after: -r--r--r--. 1 root root 28672 Jul 13 11:32 system/node/node0/cpulist -r--r--r--. 1 root root 4096 Jul 13 11:31 system/node/node0/cpumap CONFIG_NR_CPUS = 16384 -r--r--r--. 1 root root 57344 Jul 13 14:03 system/node/node0/cpulist -r--r--r--. 1 root root 4607 Jul 13 14:02 system/node/node0/cpumap The actual number of cpus doesn't matter for the reported size since they are based on NR_CPUS. Fixes: 75bd50fa841d ("drivers/base/node.c: use bin_attribute to break the size limitation of cpumap ABI") Fixes: bb9ec13d156e ("topology: use bin_attribute to break the size limitation of cpumap ABI") Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Yury Norov Cc: stable@vger.kernel.org Acked-by: Yury Norov (for include/linux/cpumask.h) Signed-off-by: Phil Auld Link: https://lore.kernel.org/r/20220715134924.3466194-1-pauld@redhat.com Signed-off-by: Greg Kroah-Hartman

topology: Fix up build warning in topology_is_visible()

2022-04-23T10:53:11+00:00

Commit aa63a74d4535 ("topology/sysfs: Hide PPIN on systems that do not support it.") caused a build warning on some configurations: drivers/base/topology.c: In function 'topology_is_visible': drivers/base/topology.c:158:24: warning: unused variable 'dev' [-Wunused-variable] 158 | struct device *dev = kobj_to_dev(kobj); Fix this up by getting rid of the variable entirely. Fixes: aa63a74d4535 ("topology/sysfs: Hide PPIN on systems that do not support it.") Cc: Tony Luck Reported-by: Stephen Rothwell Link: https://lore.kernel.org/r/20220422062653.3899972-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

topology/sysfs: Hide PPIN on systems that do not support it.

2022-04-20T16:56:39+00:00

Systems that do not support a Protected Processor Identification Number currently report: # cat /sys/devices/system/cpu/cpu0/topology/ppin 0x0 which is confusing/wrong. Add a ".is_visible" function to suppress inclusion of the ppin file. Fixes: ab28e944197f ("topology/sysfs: Add PPIN in sysfs under cpu topology") Signed-off-by: Tony Luck Link: https://lore.kernel.org/r/20220406220150.63855-1-tony.luck@intel.com Signed-off-by: Greg Kroah-Hartman

topology/sysfs: Add PPIN in sysfs under cpu topology

2022-02-01T15:36:42+00:00

PPIN is the Protected Processor Identification Number. This is used to identify the socket as a Field Replaceable Unit (FRU). Existing code only displays this when reporting errors. But this makes it inconvenient for large clusters to use it for its intended purpose of inventory control. Add ppin to /sys/devices/system/cpu/cpu*/topology to make what is already available using RDMSR more easily accessible. Make the file read only for root in case there are still people concerned about making a unique system "serial number" available. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Acked-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20220131230111.2004669-6-tony.luck@intel.com

topology/sysfs: Add format parameter to macro defining "show" functions for proc

2022-02-01T15:35:21+00:00

All the simple (non-mask and non-list files in /sys/devices/system/cpu/cpu0/topology/ are currently printed as decimal integers. Refactor the macro that generates the "show" functions to take a format parameter to allow future files to display in other formats. No functional change. Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov Acked-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20220131230111.2004669-5-tony.luck@intel.com