kernel.git/include/linux/cpu.h, branch linux-6.15.y

x86/bugs: Add a Transient Scheduler Attacks mitigation

2025-07-10T14:08:54Z

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

x86/its: Enable Indirect Target Selection mitigation

2025-05-09T20:22:05Z

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

cpu: remove needless return in void API suspend_enable_secondary_cpus()

2025-03-17T06:24:15Z

Remove needless 'return' in void API suspend_enable_secondary_cpus() since both the API and thaw_secondary_cpus() are void functions. Link: https://lkml.kernel.org/r/20250221-rmv_return-v1-2-cc8dff275827@quicinc.com Signed-off-by: Zijun Hu Signed-off-by: Andrew Morton

riscv: Add ghostwrite vulnerability

2025-01-18T20:33:39Z

Follow the patterns of the other architectures that use GENERIC_CPU_VULNERABILITIES for riscv to introduce the ghostwrite vulnerability and mitigation. The mitigation is to disable all vector which is accomplished by clearing the bit from the cpufeature field. Ghostwrite only affects thead c9xx CPUs that impelment xtheadvector, so the vulerability will only be mitigated on these CPUs. Signed-off-by: Charlie Jenkins Tested-by: Yangyu Chen Link: https://lore.kernel.org/r/20241113-xtheadvector-v11-14-236c22791ef9@rivosinc.com Signed-off-by: Palmer Dabbelt

Merge tag 'mm-nonmm-stable-2024-07-21-15-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-07-22T00:56:22Z

Pull non-MM updates from Andrew Morton: - In the series "treewide: Refactor heap related implementation", Kuan-Wei Chiu has significantly reworked the min_heap library code and has taught bcachefs to use the new more generic implementation. - Yury Norov's series "Cleanup cpumask.h inclusion in core headers" reworks the cpumask and nodemask headers to make things generally more rational. - Kuan-Wei Chiu has sent along some maintenance work against our sorting library code in the series "lib/sort: Optimizations and cleanups". - More library maintainance work from Christophe Jaillet in the series "Remove usage of the deprecated ida_simple_xx() API". - Ryusuke Konishi continues with the nilfs2 fixes and clanups in the series "nilfs2: eliminate the call to inode_attach_wb()". - Kuan-Ying Lee has some fixes to the gdb scripts in the series "Fix GDB command error". - Plus the usual shower of singleton patches all over the place. Please see the relevant changelogs for details. * tag 'mm-nonmm-stable-2024-07-21-15-07' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (98 commits) ia64: scrub ia64 from poison.h watchdog/perf: properly initialize the turbo mode timestamp and rearm counter tsacct: replace strncpy() with strscpy() lib/bch.c: use swap() to improve code test_bpf: convert comma to semicolon init/modpost: conditionally check section mismatch to __meminit* init: remove unused __MEMINIT* macros nilfs2: Constify struct kobj_type nilfs2: avoid undefined behavior in nilfs_cnt32_ge macro math: rational: add missing MODULE_DESCRIPTION() macro lib/zlib: add missing MODULE_DESCRIPTION() macro fs: ufs: add MODULE_DESCRIPTION() lib/rbtree.c: fix the example typo ocfs2: add bounds checking to ocfs2_check_dir_entry() fs: add kernel-doc comments to ocfs2_prepare_orphan_dir() coredump: simplify zap_process() selftests/fpu: add missing MODULE_DESCRIPTION() macro compiler.h: simplify data_race() macro build-id: require program headers to be right after ELF header resource: add missing MODULE_DESCRIPTION() ...

cpumask: cleanup core headers inclusion

2024-06-25T05:25:02Z

Many core headers include cpumask.h for nothing. Drop it. Link: https://lkml.kernel.org/r/20240528005648.182376-6-yury.norov@gmail.com Signed-off-by: Yury Norov Cc: Amit Daniel Kachhap Cc: Anna-Maria Behnsen Cc: Christoph Lameter Cc: Daniel Lezcano Cc: Dennis Zhou Cc: Frederic Weisbecker Cc: Johannes Weiner Cc: Juri Lelli Cc: Kees Cook Cc: Mathieu Desnoyers Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Rasmus Villemoes Cc: Tejun Heo Cc: Thomas Gleixner Cc: Ulf Hansson Cc: Vincent Guittot Cc: Viresh Kumar Cc: Yury Norov Signed-off-by: Andrew Morton

cpu: Move CPU hotplug function declarations into their own header

2024-06-10T06:50:01Z

Avoid upcoming #include hell when wants to use lockdep_assert_cpus_held() and creates a #include loop that would break the build for arch/riscv. [ bp: s/cpu/CPU/g ] Signed-off-by: Tony Luck Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240610003927.341707-2-tony.luck@intel.com

cpu: Ignore "mitigations" kernel parameter if CPU_MITIGATIONS=n

2024-04-25T13:47:39Z

Explicitly disallow enabling mitigations at runtime for kernels that were built with CONFIG_CPU_MITIGATIONS=n, as some architectures may omit code entirely if mitigations are disabled at compile time. E.g. on x86, a large pile of Kconfigs are buried behind CPU_MITIGATIONS, and trying to provide sane behavior for retroactively enabling mitigations is extremely difficult, bordering on impossible. E.g. page table isolation and call depth tracking require build-time support, BHI mitigations will still be off without additional kernel parameters, etc. [ bp: Touchups. ] Signed-off-by: Sean Christopherson Signed-off-by: Borislav Petkov (AMD) Acked-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20240420000556.2645001-3-seanjc@google.com

Merge tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2024-03-21T20:34:15Z

Pull driver core updates from Greg KH: "Here is the "big" set of driver core and kernfs changes for 6.9-rc1. Nothing all that crazy here, just some good updates that include: - automatic attribute group hiding from Dan Williams (he fixed up my horrible attempt at doing this.) - kobject lock contention fixes from Eric Dumazet - driver core cleanups from Andy - kernfs rcu work from Tejun - fw_devlink changes to resolve some reported issues - other minor changes, all details in the shortlog All of these have been in linux-next for a long time with no reported issues" * tag 'driver-core-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits) device: core: Log warning for devices pending deferred probe on timeout driver: core: Use dev_* instead of pr_* so device metadata is added driver: core: Log probe failure as error and with device metadata of: property: fw_devlink: Add support for "post-init-providers" property driver core: Add FWLINK_FLAG_IGNORE to completely ignore a fwnode link driver core: Adds flags param to fwnode_link_add() debugfs: fix wait/cancellation handling during remove device property: Don't use "proxy" headers device property: Move enum dev_dma_attr to fwnode.h driver core: Move fw_devlink stuff to where it belongs driver core: Drop unneeded 'extern' keyword in fwnode.h firmware_loader: Suppress warning on FW_OPT_NO_WARN flag sysfs:Addresses documentation in sysfs_merge_group and sysfs_unmerge_group. firmware_loader: introduce __free() cleanup hanler platform-msi: Remove usage of the deprecated ida_simple_xx() API sysfs: Introduce DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE() sysfs: Document new "group visible" helpers sysfs: Fix crash on empty group attributes array sysfs: Introduce a mechanism to hide static attribute_groups sysfs: Introduce a mechanism to hide static attribute_groups ...

Merge tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-03-12T16:31:39Z

Pull x86 RFDS mitigation from Dave Hansen: "RFDS is a CPU vulnerability that may allow a malicious userspace to infer stale register values from kernel space. Kernel registers can have all kinds of secrets in them so the mitigation is basically to wait until the kernel is about to return to userspace and has user values in the registers. At that point there is little chance of kernel secrets ending up in the registers and the microarchitectural state can be cleared. This leverages some recent robustness fixes for the existing MDS vulnerability. Both MDS and RFDS use the VERW instruction for mitigation" * tag 'rfds-for-linus-2024-03-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: KVM/x86: Export RFDS_NO and RFDS_CLEAR to guests x86/rfds: Mitigate Register File Data Sampling (RFDS) Documentation/hw-vuln: Add documentation for RFDS x86/mmio: Disable KVM mitigation when X86_FEATURE_CLEAR_CPU_BUF is set