kernel/arch/s390/mm/fault.c, branch linux-rolling-lts

Merge tag 's390-6.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2025-06-07T01:02:37Z

Pull more s390 updates from Heiko Carstens: - Add missing select CRYPTO_ENGINE to CRYPTO_PAES_S390 - Fix secure storage access exception handling when fault handling is disabled * tag 's390-6.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/mm: Fix in_atomic() handling in do_secure_storage_access() s390/crypto: Select crypto engine in Kconfig when PAES is chosen

s390/mm: Fix in_atomic() handling in do_secure_storage_access()

2025-06-05T10:29:22Z

Kernel user spaces accesses to not exported pages in atomic context incorrectly try to resolve the page fault. With debug options enabled call traces like this can be seen: BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1523 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 419074, name: qemu-system-s39 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 INFO: lockdep is turned off. Preemption disabled at: [<00000383ea47cfa2>] copy_page_from_iter_atomic+0xa2/0x8a0 CPU: 12 UID: 0 PID: 419074 Comm: qemu-system-s39 Tainted: G W 6.16.0-20250531.rc0.git0.69b3a602feac.63.fc42.s390x+debug #1 PREEMPT Tainted: [W]=WARN Hardware name: IBM 3931 A01 703 (LPAR) Call Trace: [<00000383e990d282>] dump_stack_lvl+0xa2/0xe8 [<00000383e99bf152>] __might_resched+0x292/0x2d0 [<00000383eaa7c374>] down_read+0x34/0x2d0 [<00000383e99432f8>] do_secure_storage_access+0x108/0x360 [<00000383eaa724b0>] __do_pgm_check+0x130/0x220 [<00000383eaa842e4>] pgm_check_handler+0x114/0x160 [<00000383ea47d028>] copy_page_from_iter_atomic+0x128/0x8a0 ([<00000383ea47d016>] copy_page_from_iter_atomic+0x116/0x8a0) [<00000383e9c45eae>] generic_perform_write+0x16e/0x310 [<00000383e9eb87f4>] ext4_buffered_write_iter+0x84/0x160 [<00000383e9da0de4>] vfs_write+0x1c4/0x460 [<00000383e9da123c>] ksys_write+0x7c/0x100 [<00000383eaa7284e>] __do_syscall+0x15e/0x280 [<00000383eaa8417e>] system_call+0x6e/0x90 INFO: lockdep is turned off. It is not allowed to take the mmap_lock while in atomic context. Therefore handle such a secure storage access fault as if the accessed page is not mapped: the uaccess function will return -EFAULT, and the caller has to deal with this. Usually this means that the access is retried in process context, which allows to resolve the page fault (or in this case export the page). Reviewed-by: Claudio Imbrenda Acked-by: Alexander Gordeev Acked-by: Christian Borntraeger Link: https://lore.kernel.org/r/20250603134936.1314139-1-hca@linux.ibm.com Signed-off-by: Heiko Carstens

s390: Remove unneeded includes

2025-05-28T15:48:04Z

Many files don't need to include asm/tlb.h or asm/gmap.h. On the other hand, asm/tlb.h does need to include asm/gmap.h. Remove all unneeded includes so that asm/tlb.h is not directly used by s390 arch code anymore. Remove asm/gmap.h from a few other files as well, so that now only KVM code, mm/gmap.c, and asm/tlb.h include it. Reviewed-by: Christoph Schlameuss Reviewed-by: Steffen Eiden Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20250528095502.226213-2-imbrenda@linux.ibm.com Signed-off-by: Claudio Imbrenda Message-ID: <20250528095502.226213-2-imbrenda@linux.ibm.com>

s390/mm: Dump fault info in case of low address protection fault

2025-03-31T10:20:39Z

In case of an unexpected low address protection fault in user mode dump fault info to make debugging a bit easier. At least the teid is valid, while dumping the page table is racy, since no lock is held. But it might still give some hints. Acked-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390: Move s390 sysctls into their own file under arch/s390

2025-03-18T16:13:04Z

Move s390 sysctls (spin_retry and userprocess_debug) into their own files under arch/s390. Create two new sysctl tables (2390_{fault,spin}_sysctl_table) which will be initialized with arch_initcall placing them after their original place in proc_root_init. This is part of a greater effort to move ctl tables into their respective subsystems which will reduce the merge conflicts in kernel/sysctl.c. Signed-off-by: joel granados Acked-by: Heiko Carstens Link: https://lore.kernel.org/r/20250306-jag-mv_ctltables-v2-6-71b243c8d3f8@kernel.org Signed-off-by: Vasily Gorbik

s390/cpufeature: Convert MACHINE_HAS_NX to cpu_has_nx()

2025-03-04T16:18:04Z

Convert MACHINE_HAS_... to cpu_has_...() which uses test_facility() instead of testing the machine_flags lowcore member if the feature is present. test_facility() generates better code since it results in a static branch without accessing memory. The branch is patched via alternatives by the decompressor depending on the availability of the required facility. Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/mm: Remove have_store_indication static key

2025-02-18T17:53:48Z

Whenever test_facility() is used with a constant facility number the generated code is identical to a static branch. Remove the extra initcall and static_branch_enable() handling for have_store_indication, and use test_facility() directly. Acked-by: Alexander Gordeev Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

Merge tag 's390-6.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2024-11-29T18:40:52Z

Pull more s390 updates from Heiko Carstens: - Add swap entry for hugetlbfs support - Add PTE_MARKER support for hugetlbs mappings; this fixes a regression (possible page fault loop) which was introduced when support for UFFDIO_POISON for hugetlbfs was added - Add ARCH_HAS_PREEMPT_LAZY and PREEMPT_DYNAMIC support - Mark IRQ entries in entry code, so that stack tracers can filter out the non-IRQ parts of stack traces. This fixes stack depot capacity limit warnings, since without filtering the number of unique stack traces is huge - In PCI code fix leak of struct zpci_dev object, and fix potential double remove of hotplug slot - Fix pagefault_disable() / pagefault_enable() unbalance in arch_stack_user_walk_common() - A couple of inline assembly optimizations, more cmpxchg() to try_cmpxchg() conversions, and removal of usages of xchg() and cmpxchg() on one and two byte memory areas - Various other small improvements and cleanups * tag 's390-6.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (27 commits) Revert "s390/mm: Allow large pages for KASAN shadow mapping" s390/spinlock: Use flag output constraint for arch_cmpxchg_niai8() s390/spinlock: Use R constraint for arch_load_niai4() s390/spinlock: Generate shorter code for arch_spin_unlock() s390/spinlock: Remove condition code clobber from arch_spin_unlock() s390/spinlock: Use symbolic names in inline assemblies s390: Support PREEMPT_DYNAMIC s390/pci: Fix potential double remove of hotplug slot s390/pci: Fix leak of struct zpci_dev when zpci_add_device() fails s390/mm/hugetlbfs: Add missing includes s390/mm: Add PTE_MARKER support for hugetlbfs mappings s390/mm: Introduce region-third and segment table swap entries s390/mm: Introduce region-third and segment table entry present bits s390/mm: Rearrange region-third and segment table entry SW bits KVM: s390: Increase size of union sca_utility to four bytes KVM: s390: Remove one byte cmpxchg() usage KVM: s390: Use try_cmpxchg() instead of cmpxchg() loops s390/ap: Replace xchg() with WRITE_ONCE() s390/mm: Allow large pages for KASAN shadow mapping s390: Add ARCH_HAS_PREEMPT_LAZY support ...

s390/mm: Add PTE_MARKER support for hugetlbfs mappings

2024-11-27T11:57:01Z

Commit 8a13897fb0daa ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs") added support for PTE_MARKER_POISONED for hugetlbfs, but PTE_MARKER also needs support for swap entries. For s390, swap entries were only supported on PTE level, not on the PMD/PUD levels that are used for large hugetlbfs mappings. Therefore, when writing a PTE_MARKER_POISONED entry, the resulting entry on PMD/PUD level would be an invalid / empty entry. Further access would then generate a pagefault loop, instead of the expected SIGBUS. It is a loop inside the kernel, but interruptible and uffd fault handling also calls schedule() in between, so at least it won't completely block the system. Previous commits prepared support for swap entries on PMD/PUD levels. PTE_MARKER support for hugetlbfs can now be enabled by simply adding an extra is_pte_marker() check to huge_pte_none_mostly(). Fault handling code also needs to be adjusted to expect the VM_FAULT_HWPOISON_LARGE fault flag, which was not possible on s390 before. Reviewed-by: Alexander Gordeev Signed-off-by: Gerald Schaefer Signed-off-by: Heiko Carstens

Merge tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2024-11-20T00:09:13Z

Pull vdso data page handling updates from Thomas Gleixner: "First steps of consolidating the VDSO data page handling. The VDSO data page handling is architecture specific for historical reasons, but there is no real technical reason to do so. Aside of that VDSO data has become a dump ground for various mechanisms and fail to provide a clear separation of the functionalities. Clean this up by: - consolidating the VDSO page data by getting rid of architecture specific warts especially in x86 and PowerPC. - removing the last includes of header files which are pulling in other headers outside of the VDSO namespace. - seperating timekeeping and other VDSO data accordingly. Further consolidation of the VDSO page handling is done in subsequent changes scheduled for the next merge window. This also lays the ground for expanding the VDSO time getters for independent PTP clocks in a generic way without making every architecture add support seperately" * tag 'timers-vdso-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits) x86/vdso: Add missing brackets in switch case vdso: Rename struct arch_vdso_data to arch_vdso_time_data powerpc: Split systemcfg struct definitions out from vdso powerpc: Split systemcfg data out of vdso data page powerpc: Add kconfig option for the systemcfg page powerpc/pseries/lparcfg: Use num_possible_cpus() for potential processors powerpc/pseries/lparcfg: Fix printing of system_active_processors powerpc/procfs: Propagate error of remap_pfn_range() powerpc/vdso: Remove offset comment from 32bit vdso_arch_data x86/vdso: Split virtual clock pages into dedicated mapping x86/vdso: Delete vvar.h x86/vdso: Access vdso data without vvar.h x86/vdso: Move the rng offset to vsyscall.h x86/vdso: Access rng vdso data without vvar.h x86/vdso: Access timens vdso data without vvar.h x86/vdso: Allocate vvar page from C code x86/vdso: Access rng data from kernel without vvar x86/vdso: Place vdso_data at beginning of vvar page x86/vdso: Use __arch_get_vdso_data() to access vdso data x86/mm/mmap: Remove arch_vma_name() ...