kernel/linux.git/drivers/s390/char, branch v6.19.12

s390: Unmap early KASAN shadow on memory offlining

2025-12-07T15:15:19+00:00

Teach the memory hotplug path to tear down KASAN shadow that was mapped during early boot when a memory block is offlined. Track for each sclp_mem whether its range was covered by the early KASAN shadow via an early_shadow_mapped flag. When such a block is deconfigured and removed via sclp_config_mem_store(), compute the corresponding shadow range and call vmemmap_free() to unmap the boot mapped shadow, then clear the flag. Using vmemmap_free() for the early shadow is safe despite the use of large mappings in the boot-time KASAN setup. The initial shadow is mapped with 1M and 2G pages, where possible. The minimum hotplug memory block size is 128M and always aligned (the identity mapping is at least 2G aligned), which corresponds to a 16M chunk of at least 1M aligned shadow. PMD-mapped 1M shadow pages therefore never need splitting, and PUD-mapped 2G shadow pages can now be split following the preceding changes. Relax the modify_pagetable() sanity check in vmem so that, with KASAN enabled, it may also operate on the KASAN shadow region in addition to the 1:1 mapping and vmemmap area. This allows the KASAN shadow unmapping to reuse the common vmem helpers. Signed-off-by: Vasily Gorbik Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens

s390/vmur: Use scnprintf() instead of sprintf()

2025-12-07T15:15:18+00:00

Use scnprintf() instead of sprintf() for those cases where the destination is an array and the size of the array is known at compile time. This prevents theoretical buffer overflows, but also avoids that people again and again spend time to figure out if the code is actually safe. Reviewed-by: Jan Polensky Signed-off-by: Heiko Carstens

Merge tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-05T21:52:43+00:00

Pull MM updates from Andrew Morton: "__vmalloc()/kvmalloc() and no-block support" (Uladzislau Rezki) Rework the vmalloc() code to support non-blocking allocations (GFP_ATOIC, GFP_NOWAIT) "ksm: fix exec/fork inheritance" (xu xin) Fix a rare case where the KSM MMF_VM_MERGE_ANY prctl state is not inherited across fork/exec "mm/zswap: misc cleanup of code and documentations" (SeongJae Park) Some light maintenance work on the zswap code "mm/page_owner: add debugfs files 'show_handles' and 'show_stacks_handles'" (Mauricio Faria de Oliveira) Enhance the /sys/kernel/debug/page_owner debug feature by adding unique identifiers to differentiate the various stack traces so that userspace monitoring tools can better match stack traces over time "mm/page_alloc: pcp->batch cleanups" (Joshua Hahn) Minor alterations to the page allocator's per-cpu-pages feature "Improve UFFDIO_MOVE scalability by removing anon_vma lock" (Lokesh Gidra) Address a scalability issue in userfaultfd's UFFDIO_MOVE operation "kasan: cleanups for kasan_enabled() checks" (Sabyrzhan Tasbolatov) "drivers/base/node: fold node register and unregister functions" (Donet Tom) Clean up the NUMA node handling code a little "mm: some optimizations for prot numa" (Kefeng Wang) Cleanups and small optimizations to the NUMA allocation hinting code "mm/page_alloc: Batch callers of free_pcppages_bulk" (Joshua Hahn) Address long lock hold times at boot on large machines. These were causing (harmless) softlockup warnings "optimize the logic for handling dirty file folios during reclaim" (Baolin Wang) Remove some now-unnecessary work from page reclaim "mm/damon: allow DAMOS auto-tuned for per-memcg per-node memory usage" (SeongJae Park) Enhance the DAMOS auto-tuning feature "mm/damon: fixes for address alignment issues in DAMON_LRU_SORT and DAMON_RECLAIM" (Quanmin Yan) Fix DAMON_LRU_SORT and DAMON_RECLAIM with certain userspace configuration "expand mmap_prepare functionality, port more users" (Lorenzo Stoakes) Enhance the new(ish) file_operations.mmap_prepare() method and port additional callsites from the old ->mmap() over to ->mmap_prepare() "Fix stale IOTLB entries for kernel address space" (Lu Baolu) Fix a bug (and possible security issue on non-x86) in the IOMMU code. In some situations the IOMMU could be left hanging onto a stale kernel pagetable entry "mm/huge_memory: cleanup __split_unmapped_folio()" (Wei Yang) Clean up and optimize the folio splitting code "mm, swap: misc cleanup and bugfix" (Kairui Song) Some cleanups and a minor fix in the swap discard code "mm/damon: misc documentation fixups" (SeongJae Park) "mm/damon: support pin-point targets removal" (SeongJae Park) Permit userspace to remove a specific monitoring target in the middle of the current targets list "mm: MISC follow-up patches for linux/pgalloc.h" (Harry Yoo) A couple of cleanups related to mm header file inclusion "mm/swapfile.c: select swap devices of default priority round robin" (Baoquan He) improve the selection of swap devices for NUMA machines "mm: Convert memory block states (MEM_*) macros to enums" (Israel Batista) Change the memory block labels from macros to enums so they will appear in kernel debug info "ksm: perform a range-walk to jump over holes in break_ksm" (Pedro Demarchi Gomes) Address an inefficiency when KSM unmerges an address range "mm/damon/tests: fix memory bugs in kunit tests" (SeongJae Park) Fix leaks and unhandled malloc() failures in DAMON userspace unit tests "some cleanups for pageout()" (Baolin Wang) Clean up a couple of minor things in the page scanner's writeback-for-eviction code "mm/hugetlb: refactor sysfs/sysctl interfaces" (Hui Zhu) Move hugetlb's sysfs/sysctl handling code into a new file "introduce VM_MAYBE_GUARD and make it sticky" (Lorenzo Stoakes) Make the VMA guard regions available in /proc/pid/smaps and improves the mergeability of guarded VMAs "mm: perform guard region install/remove under VMA lock" (Lorenzo Stoakes) Reduce mmap lock contention for callers performing VMA guard region operations "vma_start_write_killable" (Matthew Wilcox) Start work on permitting applications to be killed when they are waiting on a read_lock on the VMA lock "mm/damon/tests: add more tests for online parameters commit" (SeongJae Park) Add additional userspace testing of DAMON's "commit" feature "mm/damon: misc cleanups" (SeongJae Park) "make VM_SOFTDIRTY a sticky VMA flag" (Lorenzo Stoakes) Address the possible loss of a VMA's VM_SOFTDIRTY flag when that VMA is merged with another "mm: support device-private THP" (Balbir Singh) Introduce support for Transparent Huge Page (THP) migration in zone device-private memory "Optimize folio split in memory failure" (Zi Yan) "mm/huge_memory: Define split_type and consolidate split support checks" (Wei Yang) Some more cleanups in the folio splitting code "mm: remove is_swap_[pte, pmd]() + non-swap entries, introduce leaf entries" (Lorenzo Stoakes) Clean up our handling of pagetable leaf entries by introducing the concept of 'software leaf entries', of type softleaf_t "reparent the THP split queue" (Muchun Song) Reparent the THP split queue to its parent memcg. This is in preparation for addressing the long-standing "dying memcg" problem, wherein dead memcg's linger for too long, consuming memory resources "unify PMD scan results and remove redundant cleanup" (Wei Yang) A little cleanup in the hugepage collapse code "zram: introduce writeback bio batching" (Sergey Senozhatsky) Improve zram writeback efficiency by introducing batched bio writeback support "memcg: cleanup the memcg stats interfaces" (Shakeel Butt) Clean up our handling of the interrupt safety of some memcg stats "make vmalloc gfp flags usage more apparent" (Vishal Moola) Clean up vmalloc's handling of incoming GFP flags "mm: Add soft-dirty and uffd-wp support for RISC-V" (Chunyan Zhang) Teach soft dirty and userfaultfd write protect tracking to use RISC-V's Svrsw60t59b extension "mm: swap: small fixes and comment cleanups" (Youngjun Park) Fix a small bug and clean up some of the swap code "initial work on making VMA flags a bitmap" (Lorenzo Stoakes) Start work on converting the vma struct's flags to a bitmap, so we stop running out of them, especially on 32-bit "mm/swapfile: fix and cleanup swap list iterations" (Youngjun Park) Address a possible bug in the swap discard code and clean things up a little [ This merge also reverts commit ebb9aeb980e5 ("vfio/nvgrace-gpu: register device memory for poison handling") because it looks broken to me, I've asked for clarification - Linus ] * tag 'mm-stable-2025-12-03-21-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm: fix vma_start_write_killable() signal handling mm/swapfile: use plist_for_each_entry in __folio_throttle_swaprate mm/swapfile: fix list iteration when next node is removed during discard fs/proc/task_mmu.c: fix make_uffd_wp_huge_pte() huge pte handling mm/kfence: add reboot notifier to disable KFENCE on shutdown memcg: remove inc/dec_lruvec_kmem_state helpers selftests/mm/uffd: initialize char variable to Null mm: fix DEBUG_RODATA_TEST indentation in Kconfig mm: introduce VMA flags bitmap type tools/testing/vma: eliminate dependency on vma->__vm_flags mm: simplify and rename mm flags function for clarity mm: declare VMA flags by bit zram: fix a spelling mistake mm/page_alloc: optimize lowmem_reserve max lookup using its semantic monotonicity mm/vmscan: skip increasing kswapd_failures when reclaim was boosted pagemap: update BUDDY flag documentation mm: swap: remove scan_swap_map_slots() references from comments mm: swap: change swap_alloc_slow() to void mm, swap: remove redundant comment for read_swap_cache_async mm, swap: use SWP_SOLIDSTATE to determine if swap is rotational ...

s390: Remove KMSG_COMPONENT macro

2025-11-24T10:45:21+00:00

The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel message catalog" which never made it upstream. Remove the macro in order to get rid of a pointless indirection. Replace all users with the string it defines. In almost all cases this leads to a simple replacement like this: - #define KMSG_COMPONENT "appldata" - #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + #define pr_fmt(fmt) "appldata: " fmt Except for some special cases this is just mechanical/scripted work. Acked-by: Thomas Richter Signed-off-by: Heiko Carstens

s390: Remove compat support

2025-11-17T10:10:38+00:00

There shouldn't be any 31 bit code around anymore that matters. Remove the compat layer support required to run 31 bit code. Reason for removal is code simplification and reduced test effort. Note that this comes without any deprecation warnings added to config options, or kernel messages, since most likely those would be ignored anyway. If it turns out there is still a reason to keep the compat layer this can be reverted at any time in the future. Reviewed-by: Arnd Bergmann Signed-off-by: Heiko Carstens

treewide: include linux/pgalloc.h instead of asm/pgalloc.h

2025-11-17T01:28:25+00:00

For now, including instead of is technically fine unless the .c file calls p*d_populate_kernel() helper functions. But it is a better practice to always include . Include instead of outside arch/. Link: https://lkml.kernel.org/r/20251024113047.119058-3-harry.yoo@oracle.com Signed-off-by: Harry Yoo Acked-by: David Hildenbrand Reviewed-by: Lorenzo Stoakes Reviewed-by: Mike Rapoport (Microsoft) Cc: Liam Howlett Cc: Michal Hocko Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: SeongJae Park Signed-off-by: Andrew Morton

s390/sclp_mem: Consider global memory_hotplug.memmap_on_memory setting

2025-11-06T13:18:23+00:00

When the global kernel command line parameter memory_hotplug.memmap_on_memory is set to false, per-memory-block memmap_on_memory setting can still be set to true. However, when configuring memory block, add_memory_resource() would configure it without memmap_on_memory. i.e. Even if the MHP_MEMMAP_ON_MEMORY flag is set, mhp_supports_memmap_on_memory() returns false unless the kernel command line parameter "memory_hotplug.memmap_on_memory" is enabled. When both the flag and the cmdline parameter are set, the memory block can be configured with or without memmap_on_memory support. To ensure consistent behavior, permit configuring per-memory-block memmap_on_memory only when the memory_hotplug.memmap_on_memory kernel command line parameter is enabled. This is similar to commit 73954d379efd ("dax: add a sysfs knob to control memmap_on_memory behavior") Fixes: ff18dcb19aab ("s390/sclp: Add support for dynamic (de)configuration of memory") Signed-off-by: Sumanth Korikkar Reviewed-by: Heiko Carstens Signed-off-by: Heiko Carstens

Merge branch 'tape-block-sizes'

2025-10-21T08:26:26+00:00

Jan Höppner says: ==================== The tape device driver is limited to a block size of 65535 bytes since a single CCW can only transfer up to 64K-1 bytes (The count field is a 16bit value). This series introduces data chaining for all read/write functions to support block sizes larger than 65535. The tape device type 3490 (emulated) and 3590/3592 can handle up to 256K. [1] [1] https://www.ibm.com/docs/en/zos/3.1.0?topic=blksize-system-determined-block-size ==================== Signed-off-by: Heiko Carstens

s390/tape: Add support for bigger block sizes

2025-10-21T08:25:55+00:00

The tape device type 3590/3592 and emulated 3490 VTS can handle a block size of up to 256K bytes. Currently the tape device driver is limited to a block size of 65535 bytes (64K-1). This limitation stems from the maximum of 65535 bytes of data that can be transferred with one Channel-Command Word (CCW). To work around this limitation data chaining is used which uses several CCW to transfer an entire 256K block of data. A single CCW holds a maximum of 65535 bytes of data. Set MAX_BLOCKSIZE to 262144 (= 256K) to allow for data transfers with larger block sizes. The read_block() and write_block() discipline functions calculate the number of CCWs required based on the IDAL buffer array size that was created for a given block size. If there is more than one CCW required for the data transfer, the new helper function tape_ccw_dc_idal() is used to build the data chain accordingly. The Interruption-Repsonse Block (irb) is added to the tape_request struct so that the tapechar_read/write() functions can analyze what data was read or written accordingly. Signed-off-by: Jan Höppner Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens

s390/tape: Introduce idal buffer array

2025-10-21T08:25:55+00:00

The tape device driver uses a single idal_buffer for I/O. While the buffer itself can be arbitrary big, the limit for data transfer for a single Channel-Command Word is at 65535 bytes (64K-1) since the count field specifying the amount of data designated by the CCW is a 16-bit unsigned value. Provide functionality that allocates an array of multiple IDAL buffer with the limitation mentioned above in mind. A call to idal_buffer_array_alloc() allocates an array with a certain amount of IDAL buffers which is determined based on the total size of @size. Each individual buffer is limited to a size of CCW_MAX_BYTE_COUNT (65535 bytes). Add helper functions that determine the size (# of elements) and the total data size covered by the array as well. Current users of the single IDAL buffer are adapted to use the new functions with one buffer to allocate. The single IDAL buffer is removed from the tape_char_data struct. Signed-off-by: Jan Höppner Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens