pm24.git/arch/s390/include, branch master

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/spinlock: Generate shorter code for arch_spin_unlock()

2024-11-28T13:12:04Z

Use mvhhi instead of sth to write a zero to spinlocks. Compared to the sth variant this avoids the load of zero to a register, and reduces register pressure. Signed-off-by: Heiko Carstens

s390/spinlock: Remove condition code clobber from arch_spin_unlock()

2024-11-28T13:12:04Z

Both instructions in arch_spin_unlock() do not clobber the condition code. Therefore remove the condition code clobber from the inline assembly. Signed-off-by: Heiko Carstens

s390/spinlock: Use symbolic names in inline assemblies

2024-11-28T13:12:04Z

Improve readability and use symbolic names. Signed-off-by: Heiko Carstens

s390: Support PREEMPT_DYNAMIC

2024-11-28T13:12:04Z

Select HAVE_PREEMPT_DYNAMIC_KEY and add the pieces which are required to support PREEMPT_DYNAMIC. See commit 99cf983cc8bc ("sched/preempt: Add PREEMPT_DYNAMIC using static keys") and commit 1b2d3451ee50 ("arm64: Support PREEMPT_DYNAMIC") for more details. Signed-off-by: Heiko Carstens

s390/mm/hugetlbfs: Add missing includes

2024-11-28T13:11:44Z

Add missing includes to fix this randconfig compile error: All errors (new ones prefixed by >>): In file included from mm/pagewalk.c:5: In file included from include/linux/hugetlb.h:798: >> arch/s390/include/asm/hugetlb.h:94:31: error: call to undeclared function 'is_pte_marker'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 94 | return huge_pte_none(pte) || is_pte_marker(pte); | ^ Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202411281002.IPkRpIcR-lkp@intel.com/ Fixes: 487ef5d4d912 ("s390/mm: Add PTE_MARKER support for hugetlbfs mappings") Signed-off-by: Heiko Carstens

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

s390/mm: Introduce region-third and segment table swap entries

2024-11-27T11:55:21Z

Introduce region-third (PUD) and segment table (PMD) swap entries, and make hugetlbfs RSTE <-> PTE conversion code aware of them, so that they can be used for hugetlbfs PTE_MARKER entries. Future work could also build on this to enable THP_SWAP and THP_MIGRATION for s390. Similar to PTE swap entries, bits 0-51 can be used to store the swap offset, but bits 57-61 cannot be used for swap type because that overlaps with the INVALID and TABLE TYPE bits. PMD/PUD swap entries must be invalid, and have a correct table type so that pud_folded() check still works. Bits 53-57 can be used for swap type, but those include the PROTECT bit. So unlike swap PTEs, the PROTECT bit cannot be used to mark the swap entry. Use the "Common-Segment/Region" bit 59 instead for that. Also remove the !MACHINE_HAS_NX check in __set_huge_pte_at(). Otherwise, that would clear the _SEGMENT_ENTRY_NOEXEC bit also for swap entries, where it is used for encoding the swap type. The architecture only requires this bit to be 0 for PTEs, with !MACHINE_HAS_NX, not for segment or region-third entries. And the check is also redundant, because after __pte_to_rste() conversion, for non-swap PTEs it would only be set if it was already set in the PTE, which should never be the case for !MACHINE_HAS_NX. This is a prerequisite for hugetlbfs PTE_MARKER support on s390, which is needed to fix a regression introduced with commit 8a13897fb0da ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs"). That commit depends on the availability of swap entries for hugetlbfs, which were not available for s390 so far. Reviewed-by: Alexander Gordeev Signed-off-by: Gerald Schaefer Signed-off-by: Heiko Carstens

s390/mm: Introduce region-third and segment table entry present bits

2024-11-27T11:55:21Z

Introduce region-third and segment table entry present SW bits, and adjust pmd/pud_present() accordingly. Also add pmd/pud_present() checks to pmd/pud_leaf(), to return false for future swap entries. Same logic applies to pmd_trans_huge(), make that return pmd_leaf() instead of duplicating the same check. huge_pte_offset() also needs to be adjusted, current code would return NULL for !pud_present(). Use the same logic as in the generic version, which allows for !pud_present() swap entries. Similar to PTE, bit 63 can be used for the new SW present bit in region and segment table entries. For segment-table entries (PMD) the architecture says that "Bits 62-63 are available for programming", so they are safe to use. The same is true for large leaf region-third-table entries (PUD). However, for non-leaf region-third-table entries, bits 62-63 indicate the TABLE LENGTH and both must be set to 1. But such entries would always be considered as present, so it is safe to use bit 63 as PRESENT bit for PUD. They also should not conflict with bit 62 potentially later used for preserving SOFT_DIRTY in swap entries, because they are not swap entries. Valid PMDs / PUDs should always have the present bit set, so add it to the various pgprot defines, and also _SEGMENT_ENTRY which is OR'ed e.g. in pmd_populate(). _REGION3_ENTRY wouldn't need any change, as the present bit is already included in the TABLE LENGTH, but also explicitly add it there, for completeness, and just in case the bit would ever be changed. gmap code needs some adjustment, to also OR the _SEGMENT_ENTRY, like it is already done gmap_shadow_pgt() when creating new PMDs, but not in __gmap_link(). Otherwise, the gmap PMDs would not be considered present, e.g. when using pmd_leaf() checks in gmap code. The various WARN_ON checks in gmap code also need adjustment, to tolerate the new present bit. This is a prerequisite for hugetlbfs PTE_MARKER support on s390, which is needed to fix a regression introduced with commit 8a13897fb0da ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs"). That commit depends on the availability of swap entries for hugetlbfs, which were not available for s390 so far. Reviewed-by: Alexander Gordeev Signed-off-by: Gerald Schaefer Signed-off-by: Heiko Carstens

s390/mm: Rearrange region-third and segment table entry SW bits

2024-11-27T11:55:20Z

Rearrange region-third and segment table entry SW bits, in order to make room for future encoding of region/segment table swap entries. Also adjust _SEGMENT_ENTRY_GMAP_UC and _SEGMENT_ENTRY_GMAP_IN bits in gmap code. Those should only apply for gmap PMDs, and not really depend on or conflict with host PMD bits, but for consistency also adjust them: - _SEGMENT_ENTRY_GMAP_UC "dirty (migration)" was using the same bit as _SEGMENT_ENTRY_SOFT_DIRTY in the host PMD -> make it use the new SOFT_DIRTY bit 63 (0x0002) - _SEGMENT_ENTRY_GMAP_IN "invalidation notify bit" was using 0x8000, which was an unused bit in the host PMD, that is now used for _SEGMENT_ENTRY_WRITE -> make it use bit 52 (0x0800) instead, which is still unused in the host PMD This is a prerequisite for hugetlbfs PTE_MARKER support on s390, which is needed to fix a regression introduced with commit 8a13897fb0da ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs"). That commit depends on the availability of swap entries for hugetlbfs, which were not available for s390 so far. Reviewed-by: Alexander Gordeev Signed-off-by: Gerald Schaefer Signed-off-by: Heiko Carstens