lwn.git/arch/um/include/asm/Kbuild, branch master

ring-buffer: Flush and stop persistent ring buffer on panic

2026-05-21T12:20:58+00:00

On real hardware, panic and machine reboot may not flush hardware cache to memory. This means the persistent ring buffer, which relies on a coherent state of memory, may not have its events written to the buffer and they may be lost. Moreover, there may be inconsistency with the counters which are used for validation of the integrity of the persistent ring buffer which may cause all data to be discarded. To avoid this issue, stop recording of the ring buffer on panic and flush the cache of the ring buffer's memory. Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Cc: stable@vger.kernel.org Cc: Will Deacon Cc: Mathieu Desnoyers Cc: Ian Rogers Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) Acked-by: Catalin Marinas Acked-by: Geert Uytterhoeven Signed-off-by: Steven Rostedt

x86/asm: Remove ANNOTATE_DATA_SPECIAL usage

2025-12-03T15:53:19+00:00

Instead of manually annotating each __ex_table entry, just make the section mergeable and store the entry size in the ELF section header. Either way works for objtool create_fake_symbols(), this way produces cleaner code generation. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://patch.msgid.link/b858cb7891c1ba0080e22a9c32595e6c302435e2.1764694625.git.jpoimboe@kernel.org

loongarch, um, xtensa: get rid of generated arch/$ARCH/include/asm/param.h

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

For loongarch and xtensa that gets them to do what x86 et.al. are doing - have asm/param.h resolve to uapi variant, which is generated by mandatory-y += param.h and contains exact same include. On um it will resolve to x86 uapi variant instead, which also contains the same include (um doesn't have uapi headers, but it does build the host ones). Reviewed-by: Arnd Bergmann Signed-off-by: Al Viro

um: x86: clean up elf specific definitions

2025-03-18T13:48:31+00:00

The file arch/x86/um/asm/module.h is equivalent to the definition of asm-generic. Thus this commit cleans up to use it. Signed-off-by: Hajime Tazaki Link: https://patch.msgid.link/2d70a0ed79ee0a0bef80ad4790063f4833dd9bed.1737348399.git.thehajime@gmail.com Signed-off-by: Johannes Berg

um: move thread info into task

2024-11-12T13:50:31+00:00

This selects the THREAD_INFO_IN_TASK option for UM and changes the way that the current task is discovered. This is trivial though, as UML already tracks the current task in cpu_tasks[] and this can be used to retrieve it. Also remove the signal handler code that copies the thread information into the IRQ stack. It is obsolete now, which also means that the mentioned race condition cannot happen anymore. Signed-off-by: Benjamin Berg Reviewed-by: Hajime Tazaki Link: https://patch.msgid.link/20241111102910.46512-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg

um: Use generic runtime constant implementation

2024-07-17T00:25:59+00:00

UML should not be using the architecture native runtime constants, since that requires also having the appropriate instruction fixups (and all the linker script details). Not that using that code would be impossible, but it's not worth it. Just point UML at the generic version. Reported-by: Nathan Chancellor Fixes: e3c92e81711d ("runtime constants: add x86 architecture support") Link: https://lore.kernel.org/all/20240716143644.GA1827132@thelio-3990X/ Signed-off-by: Linus Torvalds

um: don't generate asm/bpf_perf_event.h

2024-07-10T12:23:30+00:00

If we start validating the existence of the asm-generic side of generated headers, this one causes a warning: make[3]: *** No rule to make target 'arch/um/include/generated/asm/bpf_perf_event.h', needed by 'all'. Stop. The problem is that the asm-generic header only exists for the uapi variant, but arch/um has no uapi headers and instead uses the x86 userspace API. Add a custom file with an explicit redirect to avoid this. Signed-off-by: Arnd Bergmann

arch: Rename fbdev header and source files

2024-05-03T15:07:50+00:00

The per-architecture fbdev code has no dependencies on fbdev and can be used for any video-related subsystem. Rename the files to 'video'. Use video-sti.c on parisc as the source file depends on CONFIG_STI_CORE. On arc, arm, arm64, sh, and um the asm header file is an empty wrapper around the file in asm-generic. Let Kbuild generate the file. The build system does this automatically. Only um needs to generate video.h explicitly, so that it overrides the host architecture's header. The latter would otherwise interfere with the build. Further update all includes statements, include guards, and Makefiles. Also update a few strings and comments to refer to video instead of fbdev. v3: - arc, arm, arm64, sh: generate asm header via build system (Sam, Helge, Arnd) - um: rename fb.h to video.h - fix typo in commit message (Sam) Signed-off-by: Thomas Zimmermann Reviewed-by: Sam Ravnborg Cc: Vineet Gupta Cc: Catalin Marinas Cc: Will Deacon Cc: Huacai Chen Cc: WANG Xuerui Cc: Geert Uytterhoeven Cc: Thomas Bogendoerfer Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Yoshinori Sato Cc: Rich Felker Cc: John Paul Adrian Glaubitz Cc: "David S. Miller" Cc: Andreas Larsson Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Signed-off-by: Arnd Bergmann

um: Use asm-generic/dma-mapping.h

2022-05-27T07:00:45+00:00

If DMA (PCI over virtio) is enabled, then some drivers may enable CONFIG_DMA_OPS as well, and then we pull in the x86 definition of get_arch_dma_ops(), which uses the dma_ops symbol, which isn't defined. Since we don't have real DMA ops nor any kind of IOMMU fix this in the simplest possible way: pull in the asm-generic file instead of inheriting the x86 one. It's not clear why those drivers that do (e.g. VDPA) "select DMA_OPS", and if they'd even work with this, but chances are nobody will be wanting to do that anyway, so fixing the build failure is good enough. Reported-by: Randy Dunlap Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver") Signed-off-by: Johannes Berg Tested-by: Randy Dunlap Acked-by: Randy Dunlap Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger

Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2022-04-02T02:57:03+00:00

Pull vfs updates from Al Viro: "Assorted bits and pieces" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: aio: drop needless assignment in aio_read() clean overflow checks in count_mounts() a bit seq_file: fix NULL pointer arithmetic warning uml/x86: use x86 load_unaligned_zeropad() asm/user.h: killed unused macros constify struct path argument of finish_automount()/do_add_mount() fs: Remove FIXME comment in generic_write_checks()