kernel/linux.git/arch/x86, branch master

Merge tag 'x86-urgent-2026-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-04-24T17:05:42+00:00

Pull x86 fixes from Ingo Molnar: - Prevent deadlock during shstk sigreturn (Rick Edgecombe) - Disable FRED when PTI is forced on (Dave Hansen) - Revert a CPA INVLPGB optimization that did not properly handle discontiguous virtual addresses (Dave Hansen) * tag 'x86-urgent-2026-04-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Revert INVLPGB optimization for set_memory code x86/cpu: Disable FRED when PTI is forced on x86/shstk: Prevent deadlock during shstk sigreturn

x86/mm: Revert INVLPGB optimization for set_memory code

2026-04-24T13:42:48+00:00

tl;dr: Revert an INVLPGB optimization that did not properly handle discontiguous virtual addresses. Full story: I got a report from some graphics (i915) folks that bisected a regression in their test suite to 86e6815b316e ("x86/mm: Change cpa_flush() to call flush_kernel_range() directly"). There was a bit of flip-flopping on the exact bisect, but the code here does seem wrong to me. The i915 folks were calling set_pages_array_wc(), so using the CPA_PAGES_ARRAY mode. Basically, the 'struct cpa_data' can wrap up all kinds of page table changes. Some of these are virtually contiguous, but some are very much not which is one reason why there are ->vaddr and ->pages arrays. 86e6815b316e made the mistake of assuming that the virtual addresses in the cpa_data are always contiguous. It got things right when neither CPA_ARRAY/CPA_PAGES_ARRAY is used, but theoretically wrong when either of those is used. In the i915 case, it probably failed to flush some WB TLB entries and install WC ones, leaving some data in the caches and not flushing it out to where the device could see it. That eventually caused graphics problems. Revert the INVLPGB optimization. It can be reintroduced later, but it will need to be a bit careful about the array modes. Fixes: 86e6815b316ec ("x86/mm: Change cpa_flush() to call flush_kernel_range()") Reported-by: Cui, Ling Signed-off-by: Dave Hansen Signed-off-by: Ingo Molnar Reviewed-by: Rick Edgecombe Reviewed-by: Thomas Hellström Link: https://patch.msgid.link/20260421151909.6B3281C6@davehans-spike.ostc.intel.com

Merge tag 'pcmcia-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux

2026-04-23T18:22:16+00:00

Pull PCMCIA updates from Dominik Brodowski: "A number of minor PCMCIA bugfixes and cleanups, and a patch removing obsolete host controller drivers" * tag 'pcmcia-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux: pcmcia: remove obsolete host controller drivers pcmcia: Convert to use less arguments in pci_bus_for_each_resource() PCMCIA: Fix garbled log messages for KERN_CONT

Merge tag 'kgdb-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux

2026-04-22T21:26:58+00:00

Pull kgdb update from Daniel Thompson: "Only a very small update for kgdb this cycle: a single patch from Kexin Sun that fixes some outdated comments" * tag 'kgdb-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux: kgdb: update outdated references to kgdb_wait()

Merge tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2026-04-22T18:13:45+00:00

Pull s390 updates from Vasily Gorbik: - Add support for CONFIG_PAGE_TABLE_CHECK and enable it in debug_defconfig. s390 can only tell user from kernel PTEs via the mm, so mm_struct is now passed into pxx_user_accessible_page() callbacks - Expose the PCI function UID as an arch-specific slot attribute in sysfs so a function can be identified by its user-defined id while still in standby. Introduces a generic ARCH_PCI_SLOT_GROUPS hook in drivers/pci/slot.c - Refresh s390 PCI documentation to reflect current behavior and cover previously undocumented sysfs attributes - zcrypt device driver cleanup series: consistent field types, clearer variable naming, a kernel-doc warning fix, and a comment explaining the intentional synchronize_rcu() in pkey_handler_register() - Provide an s390 arch_raw_cpu_ptr() that avoids the detour via get_lowcore() using alternatives, shrinking defconfig by ~27 kB - Guard identity-base randomization with kaslr_enabled() so nokaslr keeps the identity mapping at 0 even with RANDOMIZE_IDENTITY_BASE=y - Build S390_MODULES_SANITY_TEST as a module only by requiring KUNIT && m, since built-in would not exercise module loading - Remove the permanently commented-out HMCDRV_DEV_CLASS create_class() code in the hmcdrv driver - Drop stale ident_map_size extern conflicting with asm/page.h * tag 's390-7.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/zcrypt: Fix warning about wrong kernel doc comment PCI: s390: Expose the UID as an arch specific PCI slot attribute docs: s390/pci: Improve and update PCI documentation s390/pkey: Add comment about synchronize_rcu() to pkey base s390/hmcdrv: Remove commented out code s390/zcrypt: Slight rework on the agent_id field s390/zcrypt: Explicitly use a card variable in _zcrypt_send_cprb s390/zcrypt: Rework MKVP fields and handling s390/zcrypt: Make apfs a real unsigned int field s390/zcrypt: Rework domain processing within zcrypt device driver s390/zcrypt: Move inline function rng_type6cprb_msgx from header to code s390/percpu: Provide arch_raw_cpu_ptr() s390: Enable page table check for debug_defconfig s390/pgtable: Add s390 support for page table check s390/pgtable: Use set_pmd_bit() to invalidate PMD entry mm/page_table_check: Pass mm_struct to pxx_user_accessible_page() s390/boot: Respect kaslr_enabled() for identity randomization s390/Kconfig: Make modules sanity test a module-only option s390/setup: Drop stale ident_map_size declaration

Merge tag 'hyperv-next-signed-20260421' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

2026-04-22T16:50:46+00:00

Pull Hyper-V updates from Wei Liu: - Fix cross-compilation for hv tools (Aditya Garg) - Fix vmemmap_shift exceeding MAX_FOLIO_ORDER in mshv_vtl (Naman Jain) - Limit channel interrupt scan to relid high water mark (Michael Kelley) - Export hv_vmbus_exists() and use it in pci-hyperv (Dexuan Cui) - Fix cleanup and shutdown issues for MSHV (Jork Loeser) - Introduce more tracing support for MSHV (Stanislav Kinsburskii) * tag 'hyperv-next-signed-20260421' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: x86/hyperv: Skip LP/VP creation on kexec x86/hyperv: move stimer cleanup to hv_machine_shutdown() Drivers: hv: vmbus: fix hyperv_cpuhp_online variable shadowing mshv: Add tracepoint for GPA intercept handling mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER tools: hv: Fix cross-compilation Drivers: hv: vmbus: Export hv_vmbus_exists() and use it in pci-hyperv mshv: Introduce tracing support Drivers: hv: vmbus: Limit channel interrupt scan to relid high water mark

x86/hyperv: Skip LP/VP creation on kexec

2026-04-22T06:23:25+00:00

After a kexec the logical processors and virtual processors already exist in the hypervisor because they were created by the previous kernel. Attempting to add them again causes either a BUG_ON or corrupted VP state leading to MCEs in the new kernel. Add hv_lp_exists() to probe whether an LP is already present by calling HVCALL_GET_LOGICAL_PROCESSOR_RUN_TIME. When it succeeds the LP exists and we skip the add-LP and create-VP loops entirely. Also add hv_call_notify_all_processors_started() which informs the hypervisor that all processors are online. This is required after adding LPs (fresh boot) and is a no-op on kexec since we skip that path. Co-developed-by: Anirudh Rayabharam Signed-off-by: Anirudh Rayabharam Co-developed-by: Stanislav Kinsburskii Signed-off-by: Stanislav Kinsburskii Co-developed-by: Mukesh Rathor Signed-off-by: Mukesh Rathor Signed-off-by: Jork Loeser Reviewed-by: Stanislav Kinsburskii Signed-off-by: Wei Liu

x86/hyperv: move stimer cleanup to hv_machine_shutdown()

2026-04-22T06:23:25+00:00

Move hv_stimer_global_cleanup() from vmbus's hv_kexec_handler() to hv_machine_shutdown() in the platform code. This ensures stimer cleanup happens before the vmbus unload, which is required for root partition kexec to work correctly. Co-developed-by: Anirudh Rayabharam Signed-off-by: Anirudh Rayabharam Signed-off-by: Jork Loeser Reviewed-by: Stanislav Kinsburskii Signed-off-by: Wei Liu

x86/cpu: Disable FRED when PTI is forced on

2026-04-21T22:11:40+00:00

FRED and PTI were never intended to work together. No FRED hardware is vulnerable to Meltdown and all of it should have LASS anyway. Nevertheless, if you boot a system with pti=on and fred=on, the kernel tries to do what is asked of it and dies a horrible death on the first attempt to run userspace (since it never switches to the user page tables). Disable FRED when PTI is forced on, and print a warning about it. A quick brain dump about what a FRED+PTI implementation would look like is below. I'm not sure it would make any sense to do it, but never say never. All I know is that it's way too complicated to be worth it today. The SWITCH_TO_USER/KERNEL_CR3 bits are simple to fix (or at least we have the assembly tools to do it already), as is sticking the FRED entry text in .entry.text (it's not in there today). The nasty part is the stacks. Today, the CPU pops into the kernel on MSR_IA32_FRED_RSP0 which is normal old kernel memory and not mapped to userspace. The hardware pushes gunk on to MSR_IA32_FRED_RSP0, which is currently the task stacks. MSR_IA32_FRED_RSP0 would need to point elsewhere, probably cpu_entry_stack(). Then, start playing games with stacks on entry/exit, including copying gunk to and from the task stack. While I'd *like* to have PTI everywhere, I'm not sure it's worth mucking up the FRED code with PTI kludges. If a user wants fast entry/exit, they use FRED. If you want PTI (and sekuritay), you certainly don't care about fast entry and FRED isn't going to help you *all* that much, so you can just stay with the IDT. Plus, FRED hardware should have LASS which gives you a similar security profile to PTI without the CR3 munging. Reported-by: Gayatri Kammela Signed-off-by: Dave Hansen Reviewed-by: Borislav Petkov (AMD) Tested-by: Maciej Wieczor-Retman Cc:stable@vger.kernel.org Link: https://patch.msgid.link/20260421163136.E7C6788A@davehans-spike.ostc.intel.com

kgdb: update outdated references to kgdb_wait()

2026-04-21T15:41:54+00:00

The function kgdb_wait() was folded into the static function kgdb_cpu_enter() by commit 62fae312197a ("kgdb: eliminate kgdb_wait(), all cpus enter the same way"). Update the four stale references accordingly: - include/linux/kgdb.h and arch/x86/kernel/kgdb.c: the kgdb_roundup_cpus() kdoc describes what other CPUs are rounded up to call. Because kgdb_cpu_enter() is static, the correct public entry point is kgdb_handle_exception(); also fix a pre-existing grammar error ("get them be" -> "get them into") and reflow the text. - kernel/debug/debug_core.c: replace with the generic description "the debug trap handler", since the actual entry path is architecture-specific. - kernel/debug/gdbstub.c: kgdb_cpu_enter() is correct here (it describes internal state, not a call target); add the missing parentheses. Suggested-by: Daniel Thompson Assisted-by: unnamed:deepseek-v3.2 coccinelle Signed-off-by: Kexin Sun