kernel.git/arch/um/kernel/mem.c, branch linux-rolling-stable

um: Remove fixaddr_user_init()

2025-11-06T12:02:33Z

With the removal of the vDSO passthrough from the host, FIXADDR_USER_START is always 0 and fixaddr_user_init() is dead code. Remove it. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-6-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg

um: Remove file-based iomem emulation support

2025-10-27T15:37:12Z

The file-based iomem emulation was introduced to support writing paravirtualized drivers based on emulated iomem regions. However, the only driver that makes use of it is an example driver called mmapper, which was written over two decades ago. We now have several modern device emulation mechanisms, such as vhost-user-based virtio-uml. Remove the file-based iomem emulation support to reduce the maintenance burden. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20251027054519.1996090-5-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

um: Replace UML_ROUND_UP() with PAGE_ALIGN()

2025-10-27T15:37:12Z

Although UML_ROUND_UP() is defined in a shared header file, it depends on the PAGE_SIZE and PAGE_MASK macros, so it can only be used in kernel code. Considering its name is not very clear and its functionality is the same as PAGE_ALIGN(), replace its usages with a direct call to PAGE_ALIGN() and remove it. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20251027054519.1996090-4-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

kasan: introduce ARCH_DEFER_KASAN and unify static key across modes

2025-09-21T21:21:58Z

Patch series "kasan: unify kasan_enabled() and remove arch-specific implementations", v6. This patch series addresses the fragmentation in KASAN initialization across architectures by introducing a unified approach that eliminates duplicate static keys and arch-specific kasan_arch_is_ready() implementations. The core issue is that different architectures have inconsistent approaches to KASAN readiness tracking: - PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready() - Only HW_TAGS mode had a unified static key (kasan_flag_enabled) - Generic and SW_TAGS modes relied on arch-specific solutions or always-on behavior This patch (of 2): Introduce CONFIG_ARCH_DEFER_KASAN to identify architectures [1] that need to defer KASAN initialization until shadow memory is properly set up, and unify the static key infrastructure across all KASAN modes. [1] PowerPC, UML, LoongArch selects ARCH_DEFER_KASAN. The core issue is that different architectures haveinconsistent approaches to KASAN readiness tracking: - PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready() - Only HW_TAGS mode had a unified static key (kasan_flag_enabled) - Generic and SW_TAGS modes relied on arch-specific solutions or always-on behavior This patch addresses the fragmentation in KASAN initialization across architectures by introducing a unified approach that eliminates duplicate static keys and arch-specific kasan_arch_is_ready() implementations. Let's replace kasan_arch_is_ready() with existing kasan_enabled() check, which examines the static key being enabled if arch selects ARCH_DEFER_KASAN or has HW_TAGS mode support. For other arch, kasan_enabled() checks the enablement during compile time. Now KASAN users can use a single kasan_enabled() check everywhere. Link: https://lkml.kernel.org/r/20250810125746.1105476-1-snovitoll@gmail.com Link: https://lkml.kernel.org/r/20250810125746.1105476-2-snovitoll@gmail.com Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217049 Signed-off-by: Sabyrzhan Tasbolatov Reviewed-by: Christophe Leroy Reviewed-by: Ritesh Harjani (IBM) #powerpc Cc: Alexander Gordeev Cc: Alexander Potapenko Cc: Alexandre Ghiti Cc: Alexandre Ghiti Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Baoquan He Cc: David Gow Cc: Dmitriy Vyukov Cc: Heiko Carstens Cc: Huacai Chen Cc: Marco Elver Cc: Qing Zhang Cc: Sabyrzhan Tasbolatov Cc: Vincenzo Frascino Signed-off-by: Andrew Morton

Merge tag 'uml-for-linux-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2025-04-02T19:25:03Z

Pull UML updates from Johannes Berg: - proper nofault accesses and read-only rodata - hostfs fix for host inode number reuse - fixes for host errno handling - various cleanups/small fixes * tag 'uml-for-linux-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Rewrite the sigio workaround based on epoll and tgkill um: Prohibit the VM_CLONE flag in run_helper_thread() um: Switch to the pthread-based helper in sigio workaround um: ubd: Switch to the pthread-based helper um: Add pthread-based helper support um: x86: clean up elf specific definitions um: Store full CSGSFS and SS register from mcontext um: virt-pci: Refactor virtio_pcidev into its own module um: work around sched_yield not yielding in time-travel mode um/locking: Remove semicolon from "lock" prefix um: Update min_low_pfn to match changes in uml_reserved um: use str_yes_no() to remove hardcoded "yes" and "no" um: hostfs: avoid issues on inode number reuse by host um: Allocate vdso page pointer statically um: remove copy_from_kernel_nofault_allowed um: mark rodata read-only and implement _nofault accesses um: Pass the correct Rust target and options with gcc

um: Update min_low_pfn to match changes in uml_reserved

2025-03-18T10:04:39Z

When uml_reserved is updated, min_low_pfn must also be updated accordingly. Otherwise, min_low_pfn will not accurately reflect the lowest available PFN. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20250221041855.1156109-1-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg

um: mark rodata read-only and implement _nofault accesses

2025-03-18T10:03:14Z

Mark read-only data actually read-only (simple mprotect), and to be able to test it also implement _nofault accesses. This works by setting up a new "segv_continue" pointer in current, and then when we hit a segfault we change the signal return context so that we continue at that address. The code using this sets it up so that it jumps to a label and then aborts the access that way, returning -EFAULT. It's possible to optimize the ___backtrack_faulted() thing by using asm goto (compiler version dependent) and/or gcc's (not sure if clang has it) &&label extension, but at least in one attempt I made the && caused the compiler to not load -EFAULT into the register in case of jumping to the &&label from the fault handler. So leave it like this for now. Signed-off-by: Johannes Berg Co-developed-by: Benjamin Berg Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20250210160926.420133-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg

arch, mm: make releasing of memory to page allocator more explicit

2025-03-18T05:06:53Z

The point where the memory is released from memblock to the buddy allocator is hidden inside arch-specific mem_init()s and the call to memblock_free_all() is needlessly duplicated in every artiste cure and after introduction of arch_mm_preinit() hook, mem_init() implementation on many architecture only contains the call to memblock_free_all(). Pull memblock_free_all() call into mm_core_init() and drop mem_init() on relevant architectures to make it more explicit where the free memory is released from memblock to the buddy allocator and to reduce code duplication in architecture specific code. Link: https://lkml.kernel.org/r/20250313135003.836600-14-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Dave Hansen [x86] Acked-by: Geert Uytterhoeven [m68k] Tested-by: Mark Brown Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Borislav Betkov Cc: Catalin Marinas Cc: David S. Miller Cc: Dinh Nguyen Cc: Gerald Schaefer Cc: Guo Ren (csky) Cc: Heiko Carstens Cc: Helge Deller Cc: Huacai Chen Cc: Ingo Molnar Cc: Jiaxun Yang Cc: Johannes Berg Cc: John Paul Adrian Glaubitz Cc: Madhavan Srinivasan Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Palmer Dabbelt Cc: Richard Weinberger Cc: Russel King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleinxer Cc: Vasily Gorbik Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton

arch, mm: introduce arch_mm_preinit

2025-03-18T05:06:53Z

Currently, implementation of mem_init() in every architecture consists of one or more of the following: * initializations that must run before page allocator is active, for instance swiotlb_init() * a call to memblock_free_all() to release all the memory to the buddy allocator * initializations that must run after page allocator is ready and there is no arch-specific hook other than mem_init() for that, like for example register_page_bootmem_info() in x86 and sparc64 or simple setting of mem_init_done = 1 in several architectures * a bunch of semi-related stuff that apparently had no better place to live, for example a ton of BUILD_BUG_ON()s in parisc. Introduce arch_mm_preinit() that will be the first thing called from mm_core_init(). On architectures that have initializations that must happen before the page allocator is ready, move those into arch_mm_preinit() along with the code that does not depend on ordering with page allocator setup. On several architectures this results in reduction of mem_init() to a single call to memblock_free_all() that allows its consolidation next. Link: https://lkml.kernel.org/r/20250313135003.836600-13-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Dave Hansen [x86] Tested-by: Mark Brown Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Borislav Betkov Cc: Catalin Marinas Cc: David S. Miller Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Gerald Schaefer Cc: Guo Ren (csky) Cc: Heiko Carstens Cc: Helge Deller Cc: Huacai Chen Cc: Ingo Molnar Cc: Jiaxun Yang Cc: Johannes Berg Cc: John Paul Adrian Glaubitz Cc: Madhavan Srinivasan Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Palmer Dabbelt Cc: Richard Weinberger Cc: Russel King Cc: Stafford Horne Cc: Thomas Bogendoerfer Cc: Thomas Gleinxer Cc: Vasily Gorbik Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton

Merge tag 'uml-for-linus-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2025-01-31T02:29:40Z

Pull UML updates from Richard Weinberger: - hostfs: Convert to writepages - many cleanups: removal of dead macros, missing __init * tag 'uml-for-linus-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Remove unused asm/archparam.h header um: Include missing headers in asm/pgtable.h hostfs: Convert to writepages um: rtc: use RTC time when calculating the alarm um: Remove unused user_context function um: Remove unused THREAD_NAME_LEN macro um: Remove unused PGD_BOUND macro um: Mark setup_env_path as __init um: Mark install_fatal_handler as __init um: Mark set_stklim as __init um: Mark get_top_address as __init um: Mark parse_cache_line as __init um: Mark parse_host_cpu_flags as __init um: Count iomem_size only once in physmem calculation um: Remove obsolete fixmap support um: Remove unused MODULES_LEN macro