kernel/linux.git/arch/xtensa/include/uapi, branch v6.19.11

Merge tag 'xtensa-20250808' of https://github.com/jcmvbkbc/linux-xtensa

2025-08-09T04:35:03+00:00

Pull xtensa update from Max Filippov: - replace __ASSEMBLY__ with __ASSEMBLER__ in arch headers * tag 'xtensa-20250808' of https://github.com/jcmvbkbc/linux-xtensa: xtensa: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-uapi headers xtensa: Replace __ASSEMBLY__ with __ASSEMBLER__ in uapi headers

xtensa: get rid uapi/asm/param.h

2025-06-25T02:02:05+00:00

The only difference between it and generic is the stray (and utterly useless) definition of NGROUPS. It had been removed on all architectures back in 2004; xtensa port began prior to that and hadn't been merged until 2005, so it had missed the purge. Reviewed-by: Arnd Bergmann Signed-off-by: Al Viro

xtensa: Replace ASSEMBLY with ASSEMBLER in uapi headers

2025-06-06T08:03:35+00:00

__ASSEMBLY__ is only defined by the Makefile of the kernel, so this is not really useful for uapi headers (unless the userspace Makefile defines it, too). Let's switch to __ASSEMBLER__ which gets set automatically by the compiler when compiling assembly code. This is a completely mechanical patch (done with a simple "sed -i" statement). Cc: Chris Zankel Cc: Max Filippov Signed-off-by: Thomas Huth Message-Id: <20250314071013.1575167-39-thuth@redhat.com> Signed-off-by: Max Filippov

mm: madvise: implement lightweight guard page mechanism

2024-11-11T08:26:45+00:00

Implement a new lightweight guard page feature, that is regions of userland virtual memory that, when accessed, cause a fatal signal to arise. Currently users must establish PROT_NONE ranges to achieve this. However this is very costly memory-wise - we need a VMA for each and every one of these regions AND they become unmergeable with surrounding VMAs. In addition repeated mmap() calls require repeated kernel context switches and contention of the mmap lock to install these ranges, potentially also having to unmap memory if installed over existing ranges. The lightweight guard approach eliminates the VMA cost altogether - rather than establishing a PROT_NONE VMA, it operates at the level of page table entries - establishing PTE markers such that accesses to them cause a fault followed by a SIGSGEV signal being raised. This is achieved through the PTE marker mechanism, which we have already extended to provide PTE_MARKER_GUARD, which we installed via the generic page walking logic which we have extended for this purpose. These guard ranges are established with MADV_GUARD_INSTALL. If the range in which they are installed contain any existing mappings, they will be zapped, i.e. free the range and unmap memory (thus mimicking the behaviour of MADV_DONTNEED in this respect). Any existing guard entries will be left untouched. There is therefore no nesting of guarded pages. Guarded ranges are NOT cleared by MADV_DONTNEED nor MADV_FREE (in both instances the memory range may be reused at which point a user would expect guards to still be in place), but they are cleared via MADV_GUARD_REMOVE, process teardown or unmapping of memory ranges. The guard property can be removed from ranges via MADV_GUARD_REMOVE. The ranges over which this is applied, should they contain non-guard entries, will be untouched, with only guard entries being cleared. We permit this operation on anonymous memory only, and only VMAs which are non-special, non-huge and not mlock()'d (if we permitted this we'd have to drop locked pages which would be rather counterintuitive). Racing page faults can cause repeated attempts to install guard pages that are interrupted, result in a zap, and this process can end up being repeated. If this happens more than would be expected in normal operation, we rescind locks and retry the whole thing, which avoids lock contention in this scenario. Link: https://lkml.kernel.org/r/6aafb5821bf209f277dfae0787abb2ef87a37542.1730123433.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Suggested-by: Vlastimil Babka Suggested-by: Jann Horn Suggested-by: David Hildenbrand Suggested-by: Vlastimil Babka Suggested-by: Jann Horn Suggested-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Arnd Bergmann Cc: Christian Brauner Cc: Christoph Hellwig Cc: Chris Zankel Cc: Helge Deller Cc: James E.J. Bottomley Cc: Jeff Xu Cc: John Hubbard Cc: Liam R. Howlett Cc: Matthew Wilcox (Oracle) Cc: Matt Turner Cc: Max Filippov Cc: Muchun Song Cc: Paul E. McKenney Cc: Richard Henderson Cc: Shuah Khan Cc: Shuah Khan Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Thomas Bogendoerfer Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04+00:00

Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...

xtensa: add FDPIC and static PIE support for noMMU

2022-09-14T01:28:00+00:00

Define ELFOSABI_XTENSA_FDPIC and use it as an OSABI tag in the ELF header to distinguish FDPIC ELF files from regular ELF files. Define ELF_FDPIC_PLAT_INIT and put executable map, interpreter map and executable dynamic section addresses into registers a4..a6. Update start_thread macro to preserve register values in the current register window. Add definitions for PTRACE_GETFDPIC, PTRACE_GETFDPIC_EXEC and PTRACE_GETFDPIC_INTERP. Signed-off-by: Max Filippov

mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse

2022-09-12T03:25:46+00:00

This idea was introduced by David Rientjes[1]. Introduce a new madvise mode, MADV_COLLAPSE, that allows users to request a synchronous collapse of memory at their own expense. The benefits of this approach are: * CPU is charged to the process that wants to spend the cycles for the THP * Avoid unpredictable timing of khugepaged collapse Semantics This call is independent of the system-wide THP sysfs settings, but will fail for memory marked VM_NOHUGEPAGE. If the ranges provided span multiple VMAs, the semantics of the collapse over each VMA is independent from the others. This implies a hugepage cannot cross a VMA boundary. If collapse of a given hugepage-aligned/sized region fails, the operation may continue to attempt collapsing the remainder of memory specified. The memory ranges provided must be page-aligned, but are not required to be hugepage-aligned. If the memory ranges are not hugepage-aligned, the start/end of the range will be clamped to the first/last hugepage-aligned address covered by said range. The memory ranges must span at least one hugepage-sized region. All non-resident pages covered by the range will first be swapped/faulted-in, before being internally copied onto a freshly allocated hugepage. Unmapped pages will have their data directly initialized to 0 in the new hugepage. However, for every eligible hugepage aligned/sized region to-be collapsed, at least one page must currently be backed by memory (a PMD covering the address range must already exist). Allocation for the new hugepage may enter direct reclaim and/or compaction, regardless of VMA flags. When the system has multiple NUMA nodes, the hugepage will be allocated from the node providing the most native pages. This operation operates on the current state of the specified process and makes no persistent changes or guarantees on how pages will be mapped, constructed, or faulted in the future Return Value If all hugepage-sized/aligned regions covered by the provided range were either successfully collapsed, or were already PMD-mapped THPs, this operation will be deemed successful. On success, process_madvise(2) returns the number of bytes advised, and madvise(2) returns 0. Else, -1 is returned and errno is set to indicate the error for the most-recently attempted hugepage collapse. Note that many failures might have occurred, since the operation may continue to collapse in the event a single hugepage-sized/aligned region fails. ENOMEM Memory allocation failed or VMA not found EBUSY Memcg charging failed EAGAIN Required resource temporarily unavailable. Try again might succeed. EINVAL Other error: No PMD found, subpage doesn't have Present bit set, "Special" page no backed by struct page, VMA incorrectly sized, address not page-aligned, ... Most notable here is ENOMEM and EBUSY (new to madvise) which are intended to provide the caller with actionable feedback so they may take an appropriate fallback measure. Use Cases An immediate user of this new functionality are malloc() implementations that manage memory in hugepage-sized chunks, but sometimes subrelease memory back to the system in native-sized chunks via MADV_DONTNEED; zapping the pmd. Later, when the memory is hot, the implementation could madvise(MADV_COLLAPSE) to re-back the memory by THPs to regain hugepage coverage and dTLB performance. TCMalloc is such an implementation that could benefit from this[2]. Only privately-mapped anon memory is supported for now, but additional support for file, shmem, and HugeTLB high-granularity mappings[2] is expected. File and tmpfs/shmem support would permit: * Backing executable text by THPs. Current support provided by CONFIG_READ_ONLY_THP_FOR_FS may take a long time on a large system which might impair services from serving at their full rated load after (re)starting. Tricks like mremap(2)'ing text onto anonymous memory to immediately realize iTLB performance prevents page sharing and demand paging, both of which increase steady state memory footprint. With MADV_COLLAPSE, we get the best of both worlds: Peak upfront performance and lower RAM footprints. * Backing guest memory by hugapages after the memory contents have been migrated in native-page-sized chunks to a new host, in a userfaultfd-based live-migration stack. [1] https://lore.kernel.org/linux-mm/d098c392-273a-36a4-1a29-59731cdf5d3d@google.com/ [2] https://github.com/google/tcmalloc/tree/master/tcmalloc [jrdr.linux@gmail.com: avoid possible memory leak in failure path] Link: https://lkml.kernel.org/r/20220713024109.62810-1-jrdr.linux@gmail.com [zokeefe@google.com add missing kfree() to madvise_collapse()] Link: https://lore.kernel.org/linux-mm/20220713024109.62810-1-jrdr.linux@gmail.com/ Link: https://lkml.kernel.org/r/20220713161851.1879439-1-zokeefe@google.com [zokeefe@google.com: delay computation of hpage boundaries until use]] Link: https://lkml.kernel.org/r/20220720140603.1958773-4-zokeefe@google.com Link: https://lkml.kernel.org/r/20220706235936.2197195-10-zokeefe@google.com Signed-off-by: Zach O'Keefe Signed-off-by: "Souptick Joarder (HPE)" Suggested-by: David Rientjes Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Yang Shi Cc: Zi Yan Cc: Dan Carpenter Signed-off-by: Andrew Morton

Merge tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2022-03-28T20:00:51+00:00

Pull tty/serial driver updates from Greg KH: "Here are the big set of tty and serial driver changes for 5.18-rc1. Nothing major, some more good cleanups from Jiri and 2 new serial drivers. Highlights include: - termbits cleanups - export symbol cleanups and other core cleanups from Jiri Slaby - new sunplus and mvebu uart drivers (amazing that people are still creating new uarts...) - samsung serial driver cleanups - ldisc 29 is now "reserved" for experimental/development line disciplines - lots of other tiny fixes and cleanups to serial drivers and bindings All of these have been in linux-next for a while with no reported issues" * tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (104 commits) vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE serial: 8250: fix XOFF/XON sending when DMA is used tty: serial: samsung: Add ARTPEC-8 support dt-bindings: serial: samsung: Add ARTPEC-8 UART serial: sc16is7xx: Clear RS485 bits in the shutdown tty: serial: samsung: simplify getting OF match data tty: serial: samsung: constify variables and pointers tty: serial: samsung: constify s3c24xx_serial_drv_data members tty: serial: samsung: constify UART name tty: serial: samsung: constify s3c24xx_serial_drv_data tty: serial: samsung: reduce number of casts tty: serial: samsung: embed s3c2410_uartcfg in parent structure tty: serial: samsung: embed s3c24xx_uart_info in parent structure serial: 8250_tegra: mark acpi_device_id as unused with !ACPI tty: serial: bcm63xx: use more precise Kconfig symbol serial: SERIAL_SUNPLUS should depend on ARCH_SUNPLUS tty: serial: jsm: fix two assignments in if conditions tty: serial: jsm: remove redundant assignments to variable linestatus serial: 8250_mtk: make two read-only arrays static const serial: samsung_tty: do not unlock port->lock for uart_write_wakeup() ...

mm: madvise: MADV_DONTNEED_LOCKED

2022-03-25T02:06:51+00:00

MADV_DONTNEED historically rejects mlocked ranges, but with MLOCK_ONFAULT and MCL_ONFAULT allowing to mlock without populating, there are valid use cases for depopulating locked ranges as well. Users mlock memory to protect secrets. There are allocators for secure buffers that want in-use memory generally mlocked, but cleared and invalidated memory to give up the physical pages. This could be done with explicit munlock -> mlock calls on free -> alloc of course, but that adds two unnecessary syscalls, heavy mmap_sem write locks, vma splits and re-merges - only to get rid of the backing pages. Users also mlockall(MCL_ONFAULT) to suppress sustained paging, but are okay with on-demand initial population. It seems valid to selectively free some memory during the lifetime of such a process, without having to mess with its overall policy. Why add a separate flag? Isn't this a pretty niche usecase? - MADV_DONTNEED has been bailing on locked vmas forever. It's at least conceivable that someone, somewhere is relying on mlock to protect data from perhaps broader invalidation calls. Changing this behavior now could lead to quiet data corruption. - It also clarifies expectations around MADV_FREE and maybe MADV_REMOVE. It avoids the situation where one quietly behaves different than the others. MADV_FREE_LOCKED can be added later. - The combination of mlock() and madvise() in the first place is probably niche. But where it happens, I'd say that dropping pages from a locked region once they don't contain secrets or won't page anymore is much saner than relying on mlock to protect memory from speculative or errant invalidation calls. It's just that we can't change the default behavior because of the two previous points. Given that, an explicit new flag seems to make the most sense. [hannes@cmpxchg.org: fix mips build] Link: https://lkml.kernel.org/r/20220304171912.305060-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Reviewed-by: Mike Kravetz Reviewed-by: Shakeel Butt Acked-by: Vlastimil Babka Cc: Nadav Amit Cc: David Hildenbrand Cc: Dr. David Alan Gilbert Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

xtensa: termbits.h is identical to asm-generic one

2022-02-25T09:20:37+00:00

Remove arch specific termbits.h as there are only trivial space differences between include/uapi/asm-generic/termbits.h and arch/xtensa/include/uapi/asm/termbits.h. $ diff -u0 -b -B include/uapi/asm-generic/termbits.h arch/xtensa/include/uapi/asm/termbits.h . --- include/uapi/asm-generic/termbits.h 2022-01-10 13:44:42.814107461 +0200 . +++ arch/xtensa/include/uapi/asm/termbits.h 2022-01-10 13:44:42.690106926 +0200 . @@ -2,2 +2,15 @@ . -#ifndef __ASM_GENERIC_TERMBITS_H . -#define __ASM_GENERIC_TERMBITS_H . +/* . + * include/asm-xtensa/termbits.h . + * . + * Copied from SH. . + * . + * This file is subject to the terms and conditions of the GNU General Public . + * License. See the file "COPYING" in the main directory of this archive . + * for more details. . + * . + * Copyright (C) 2001 - 2005 Tensilica Inc. . + */ . + . +#ifndef _XTENSA_TERMBITS_H . +#define _XTENSA_TERMBITS_H . + . @@ -200 +221 @@ . -#endif /* __ASM_GENERIC_TERMBITS_H */ . +#endif /* _XTENSA_TERMBITS_H */ Reviewed-by: Andy Shevchenko Acked-by: Max Filippov Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220222115604.7351-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman