kernel/linux.git/arch/um/include/asm/pgtable.h, branch linux-7.1.y

Merge tag 'uml-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2026-04-20T23:36:46+00:00

Pull uml updates from Johannes Berg: "Mostly cleanups and small things, notably: - musl libc compatibility - vDSO installation fix - TLB sync race fix for recent SMP support - build fix for 32-bit with Clang 20/21" * tag 'uml-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Disable GCOV_PROFILE_ALL on 32-bit UML with Clang 20/21 um: drivers: call kernel_strrchr() explicitly in cow_user.c um: Replace strncpy() with strnlen()+memcpy_and_pad() in strncpy_chunk_from_user() x86/um: fix vDSO installation um: Remove CONFIG_FRAME_WARN from x86_64_defconfig um: Fix pte_read() and pte_exec() for kernel mappings um: Fix potential race condition in TLB sync um: time-travel: clean up kernel-doc warnings um: avoid struct sigcontext redefinition with musl um: fix address-of CMSG_DATA() rvalue in stub

arch, mm: consolidate empty_zero_page

2026-04-05T20:53:01+00:00

Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of ZERO_PAGE() to 4. Every architecture defines empty_zero_page that way or another, but for the most of them it is always a page aligned page in BSS and most definitions of ZERO_PAGE do virt_to_page(empty_zero_page). Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to the core MM and drop these definitions in architectures that do not implement colored zero page (MIPS and s390). ZERO_PAGE() remains a macro because turning it to a wrapper for a static inline causes severe pain in header dependencies. For the most part the change is mechanical, with these being noteworthy: * alpha: aliased empty_zero_page with ZERO_PGE that was also used for boot parameters. Switching to a generic empty_zero_page removes the aliasing and keeps ZERO_PGE for boot parameters only * arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of ZERO_PAGE() is kept intact. * m68k/parisc/um: allocated empty_zero_page from memblock, although they do not support zero page coloring and having it in BSS will work fine. * sparc64 can have empty_zero_page in BSS rather allocate it, but it can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE() but instead of allocating it, make mem_map_zero point to empty_zero_page. * sh: used empty_zero_page for boot parameters at the very early boot. Rename the parameters page to boot_params_page and let sh use the generic empty_zero_page. * hexagon: had an amusing comment about empty_zero_page /* A handy thing to have if one has the RAM. Declared in head.S */ that unfortunately had to go :) Link: https://lkml.kernel.org/r/20260211103141.3215197-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Helge Deller [parisc] Tested-by: Helge Deller [parisc] Reviewed-by: Christophe Leroy (CS GROUP) Acked-by: Dave Hansen Acked-by: Catalin Marinas Acked-by: Magnus Lindholm [alpha] Acked-by: Dinh Nguyen [nios2] Acked-by: Andreas Larsson [sparc] Acked-by: David Hildenbrand (Arm) Acked-by: Liam R. Howlett Cc: "Borislav Petkov (AMD)" Cc: David S. Miller Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Huacai Chen Cc: Ingo Molnar Cc: Johannes Berg Cc: John Paul Adrian Glaubitz Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Hocko Cc: Michal Simek Cc: Palmer Dabbelt Cc: Richard Weinberger Cc: Russell King Cc: Stafford Horne Cc: Suren Baghdasaryan Cc: Vineet Gupta Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton

um: Fix pte_read() and pte_exec() for kernel mappings

2026-03-21T09:42:24+00:00

The pte_read() and pte_exec() helpers are only used during the TLB sync to determine the read/exec permissions for mmap. However, for kernel mappings, they will always return 0. This leads to kern_map() having to unconditionally set the exec flag to 1 and the read flag unexpectedly always being 0. Remove the unnecessary check for the _PAGE_USER bit in these helpers to ensure that the kernel mapping permissions can be correctly determined. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260302235224.1915380-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg

um: Avoid circular dependency on asm-offsets in pgtable.h

2025-10-28T10:40:49+00:00

Recent changes have added an include of as-layout.h to pgtable.h. However this introduces a circular dependency during asm-offsets generation as as-layout.h depends on asm-offsets and pgtable.h is an input for asm-offsets. Building from a clean state results in the following error: CC arch/um/kernel/asm-offsets.s In file included from arch/um/include/asm/pgtable.h:48, from include/linux/pgtable.h:6, from include/linux/mm.h:31, from include/linux/pid_namespace.h:7, from include/linux/ptrace.h:10, from include/linux/audit.h:13, from arch/um/kernel/asm-offsets.c:8: arch/um/include/shared/as-layout.h:9:10: fatal error: generated/asm-offsets.h: No such file or directory 9 | #include | ^~~~~~~~~~~~~~~~~~~~~~~~~ compilation terminated. make[4]: *** [scripts/Makefile.build:182: arch/um/kernel/asm-offsets.s] Error 1 As the inclusion of as-layout.h in pgtable.h is not yet needed while asm-offsets are generated, break the dependency here. Fixes: a7f7dbae94a5 ("um: Remove file-based iomem emulation support") Signed-off-by: Thomas Weißschuh Reviewed-by: Tiwei Bie Link: https://patch.msgid.link/20251028-uml-offsets-circular-v1-1-601c363cfaaa@weissschuh.net Signed-off-by: Johannes Berg

um: Add initial SMP support

2025-10-27T15:41:15+00:00

Add initial symmetric multi-processing (SMP) support to UML. With this support enabled, users can tell UML to start multiple virtual processors, each represented as a separate host thread. In UML, kthreads and normal threads (when running in kernel mode) can be scheduled and executed simultaneously on different virtual processors. However, the userspace code of normal threads still runs within their respective single-threaded stubs. That is, SMP support is currently available both within the kernel and across different processes, but still remains limited within threads of the same process in userspace. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20251027001815.1666872-6-tiwei.bie@linux.dev Signed-off-by: Johannes Berg

um: Remove file-based iomem emulation support

2025-10-27T15:37:12+00:00

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

mm: pgtable: fix pte_swp_exclusive

2025-06-11T21:52:08+00:00

Make pte_swp_exclusive return bool instead of int. This will better reflect how pte_swp_exclusive is actually used in the code. This fixes swap/swapoff problems on Alpha due pte_swp_exclusive not returning correct values when _PAGE_SWP_EXCLUSIVE bit resides in upper 32-bits of PTE (like on alpha). Suggested-by: Al Viro Signed-off-by: Magnus Lindholm Cc: Sam James Link: https://lore.kernel.org/lkml/20250218175735.19882-2-linmag7@gmail.com/ Link: https://lore.kernel.org/lkml/20250602041118.GA2675383@ZenIV/ [ Applied as the 'sed' script Al suggested - Linus ] Signed-off-by: Linus Torvalds

um: remove custom definition of mk_pte()

2025-05-12T00:48:03+00:00

Move the pfn_pte() definitions from the 2level and 4level files to the generic pgtable.h and delete the custom definition of mk_pte() so that we use the central definition. Link: https://lkml.kernel.org/r/20250402181709.2386022-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Cc: Zi Yan Cc: Richard Weinberger Cc: Anton Ivanov Cc: Johannes Berg Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Dave Hansen Cc: David Hildenbrand Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Muchun Song Cc: Signed-off-by: Andrew Morton

um: Include missing headers in asm/pgtable.h

2025-01-13T16:19:43+00:00

Formerly, asm/pgtable.h relied on the implicit inclusion of asm/page.h and linux/mm_types.h via asm/fixmap.h. With the removal of asm/fixmap.h, these headers need to be included explicitly in asm/pgtable.h now. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202501131814.E6CxjulL-lkp@intel.com/ Fixes: 5bfc4a3a0af3 ("um: Remove obsolete fixmap support") Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20250113153218.3331321-2-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg

um: Remove obsolete fixmap support

2025-01-10T12:49:33+00:00

It was added to support highmem. But since the highmem support has been removed by commit a98a6d864d3b ("um: Remove broken highmem support"), it is no longer needed. Remove it to simplify the code. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20241128081939.2216246-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg