kernel/linux.git/Documentation/ABI/testing, branch v6.6.132

xhci: dbc: Allow users to modify DbC poll interval via sysfs

2025-11-02T13:14:41+00:00

[ Upstream commit de3edd47a18fe05a560847cc3165871474e08196 ] xhci DbC driver polls the host controller for DbC events at a reduced rate when DbC is enabled but there are no active data transfers. Allow users to modify this reduced poll interval via dbc_poll_interval_ms sysfs entry. Unit is milliseconds and accepted range is 0 to 5000. Max interval of 5000 ms is selected as it matches the common 5 second timeout used in usb stack. Default value is 64 milliseconds. A long interval is useful when users know there won't be any activity on systems connected via DbC for long periods, and want to avoid battery drainage due to unnecessary CPU usage. Example being Android Debugger (ADB) usage over DbC on ChromeOS systems running Android Runtime. [minor changes and rewording -Mathias] Co-developed-by: Samuel Jacob Signed-off-by: Samuel Jacob Signed-off-by: Uday M Bhat Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20240626124835.1023046-5-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: f3d12ec847b9 ("xhci: dbc: fix bogus 1024 byte prefix if ttyDBC read races with stall event") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

x86/vmscape: Enable the mitigation

2025-09-11T15:20:27+00:00

Commit 556c1ad666ad90c50ec8fccb930dd5046cfbecfb upstream. Enable the previously added mitigation for VMscape. Add the cmdline vmscape={off|ibpb|force} and sysfs reporting. Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Borislav Petkov (AMD) Reviewed-by: Dave Hansen Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Greg Kroah-Hartman

x86/bugs: Add a Transient Scheduler Attacks mitigation

2025-07-10T14:03:21+00:00

Commit d8010d4ba43e9f790925375a7de100604a5e2dba upstream. Add the required features detection glue to bugs.c et all in order to support the TSA mitigation. Co-developed-by: Kim Phillips Signed-off-by: Kim Phillips Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Pawan Gupta Signed-off-by: Greg Kroah-Hartman

scsi: ufs: core: Fix spelling of a sysfs attribute name

2025-07-10T14:03:07+00:00

[ Upstream commit 021f243627ead17eb6500170256d3d9be787dad8 ] Change "resourse" into "resource" in the name of a sysfs attribute. Fixes: d829fc8a1058 ("scsi: ufs: sysfs: unit descriptor") Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20250624181658.336035-1-bvanassche@acm.org Reviewed-by: Avri Altman Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin

x86/its: Enable Indirect Target Selection mitigation

2025-05-18T06:24:11+00:00

commit f4818881c47fd91fcb6d62373c57c7844e3de1c0 upstream. Indirect Target Selection (ITS) is a bug in some pre-ADL Intel CPUs with eIBRS. It affects prediction of indirect branch and RETs in the lower half of cacheline. Due to ITS such branches may get wrongly predicted to a target of (direct or indirect) branch that is located in the upper half of the cacheline. Scope of impact =============== Guest/host isolation -------------------- When eIBRS is used for guest/host isolation, the indirect branches in the VMM may still be predicted with targets corresponding to branches in the guest. Intra-mode ---------- cBPF or other native gadgets can be used for intra-mode training and disclosure using ITS. User/kernel isolation --------------------- When eIBRS is enabled user/kernel isolation is not impacted. Indirect Branch Prediction Barrier (IBPB) ----------------------------------------- After an IBPB, indirect branches may be predicted with targets corresponding to direct branches which were executed prior to IBPB. This is mitigated by a microcode update. Add cmdline parameter indirect_target_selection=off|on|force to control the mitigation to relocate the affected branches to an ITS-safe thunk i.e. located in the upper half of cacheline. Also add the sysfs reporting. When retpoline mitigation is deployed, ITS safe-thunks are not needed, because retpoline sequence is already ITS-safe. Similarly, when call depth tracking (CDT) mitigation is deployed (retbleed=stuff), ITS safe return thunk is not used, as CDT prevents RSB-underflow. To not overcomplicate things, ITS mitigation is not supported with spectre-v2 lfence;jmp mitigation. Moreover, it is less practical to deploy lfence;jmp mitigation on ITS affected parts anyways. Signed-off-by: Pawan Gupta Signed-off-by: Dave Hansen Reviewed-by: Josh Poimboeuf Reviewed-by: Alexandre Chartre Signed-off-by: Greg Kroah-Hartman

xfs: fix the contact address for the sysfs ABI documentation

2024-12-27T12:58:44+00:00

commit 9ff4490e2ab364ec433f15668ef3f5edfb53feca upstream. oss.sgi.com is long dead, refer to the current linux-xfs list instead. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Chandan Babu R Signed-off-by: Catherine Hoang Acked-by: Darrick J. Wong Signed-off-by: Sasha Levin

PCI: Add 'reset_subordinate' to reset hierarchy below bridge

2024-12-14T19:00:14+00:00

[ Upstream commit 2fa046449a82a7d0f6d9721dd83e348816038444 ] The "bus" and "cxl_bus" reset methods reset a device by asserting Secondary Bus Reset on the bridge leading to the device. These only work if the device is the only device below the bridge. Add a sysfs 'reset_subordinate' attribute on bridges that can assert Secondary Bus Reset regardless of how many devices are below the bridge. This resets all the devices below a bridge in a single command, including the locking and config space save/restore that reset methods normally do. This may be the only way to reset devices that don't support other reset methods (ACPI, FLR, PM reset, etc). Link: https://lore.kernel.org/r/20241025222755.3756162-1-kbusch@meta.com Signed-off-by: Keith Busch [bhelgaas: commit log, add capable(CAP_SYS_ADMIN) check] Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Williamson Reviewed-by: Amey Narkhede Signed-off-by: Sasha Levin

f2fs: fix to avoid use GC_AT when setting gc_mode as GC_URGENT_LOW or GC_URGENT_MID

2024-12-09T09:32:26+00:00

[ Upstream commit 296b8cb34e65fa93382cf919be5a056f719c9a26 ] If gc_mode is set to GC_URGENT_LOW or GC_URGENT_MID, cost benefit GC approach should be used, but if ATGC is enabled at the same time, Age-threshold approach will be selected, which can only do amount of GC and it is much less than the numbers of CB approach. some traces: f2fs_gc-254:48-396 [007] ..... 2311600.684028: f2fs_gc_begin: dev = (254,48), gc_type = Background GC, no_background_GC = 0, nr_free_secs = 0, nodes = 1053, dents = 2, imeta = 18, free_sec:44898, free_seg:44898, rsv_seg:239, prefree_seg:0 f2fs_gc-254:48-396 [007] ..... 2311600.684527: f2fs_get_victim: dev = (254,48), type = No TYPE, policy = (Background GC, LFS-mode, Age-threshold), victim = 10, cost = 4294364975, ofs_unit = 1, pre_victim_secno = -1, prefree = 0, free = 44898 f2fs_gc-254:48-396 [007] ..... 2311600.714835: f2fs_gc_end: dev = (254,48), ret = 0, seg_freed = 0, sec_freed = 0, nodes = 1562, dents = 2, imeta = 18, free_sec:44898, free_seg:44898, rsv_seg:239, prefree_seg:0 f2fs_gc-254:48-396 [007] ..... 2311600.714843: f2fs_background_gc: dev = (254,48), wait_ms = 50, prefree = 0, free = 44898 f2fs_gc-254:48-396 [007] ..... 2311600.771785: f2fs_gc_begin: dev = (254,48), gc_type = Background GC, no_background_GC = 0, nr_free_secs = 0, nodes = 1562, dents = 2, imeta = 18, free_sec:44898, free_seg:44898, rsv_seg:239, prefree_seg: f2fs_gc-254:48-396 [007] ..... 2311600.772275: f2fs_gc_end: dev = (254,48), ret = -61, seg_freed = 0, sec_freed = 0, nodes = 1562, dents = 2, imeta = 18, free_sec:44898, free_seg:44898, rsv_seg:239, prefree_seg:0 Fixes: 0e5e81114de1 ("f2fs: add GC_URGENT_LOW mode in gc_urgent") Fixes: d98af5f45520 ("f2fs: introduce gc_urgent_mid mode") Signed-off-by: Zhiguo Niu Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin

ABI: testing: fix admv8818 attr description

2024-10-04T14:29:39+00:00

[ Upstream commit 7d34b4ad8cd2867b130b5b8d7d76d0d6092bd019 ] Fix description of the filter_mode_available attribute by pointing to the correct name of the attribute that can be written with valid values. Fixes: bf92d87d7c67 ("iio:filter:admv8818: Add sysfs ABI documentation") Signed-off-by: Antoniu Miclaus Link: https://patch.msgid.link/20240702081851.4663-1-antoniu.miclaus@analog.com Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin

cpu/SMT: Enable SMT only if a core is online

2024-08-29T15:33:30+00:00

[ Upstream commit 6c17ea1f3eaa330d445ac14a9428402ce4e3055e ] If a core is offline then enabling SMT should not online CPUs of this core. By enabling SMT, what is intended is either changing the SMT value from "off" to "on" or setting the SMT level (threads per core) from a lower to higher value. On PowerPC the ppc64_cpu utility can be used, among other things, to perform the following functions: ppc64_cpu --cores-on # Get the number of online cores ppc64_cpu --cores-on=X # Put exactly X cores online ppc64_cpu --offline-cores=X[,Y,...] # Put specified cores offline ppc64_cpu --smt={on|off|value} # Enable, disable or change SMT level If the user has decided to offline certain cores, enabling SMT should not online CPUs in those cores. This patch fixes the issue and changes the behaviour as described, by introducing an arch specific function topology_is_core_online(). It is currently implemented only for PowerPC. Fixes: 73c58e7e1412 ("powerpc: Add HOTPLUG_SMT support") Reported-by: Tyrel Datwyler Closes: https://groups.google.com/g/powerpc-utils-devel/c/wrwVzAAnRlI/m/5KJSoqP4BAAJ Signed-off-by: Nysal Jan K.A Reviewed-by: Shrikanth Hegde Reviewed-by: Thomas Gleixner Signed-off-by: Michael Ellerman Link: https://msgid.link/20240731030126.956210-2-nysal@linux.ibm.com Signed-off-by: Sasha Levin