kernel/linux.git/arch/um/os-Linux, branch v7.0-rc7

arch/um: remove unused varible err in remove_files_and_dir()

2026-01-13T18:43:41+00:00

err is duplicated with errno, and never used; remove it. Reported-by: kernel test robot Signed-off-by: Alex Shi Link: https://patch.msgid.link/20260107064009.15380-1-alexs@kernel.org Signed-off-by: Johannes Berg

um: Handle SIGCHLD in seccomp mode like other IRQ signals

2026-01-13T18:39:09+00:00

In seccomp mode, SIGCHLD serves as the child reaper IRQ. So, let's handle it in the same way as other IRQ signals, including preventing them from nesting with each other and allowing interrupted syscalls to be automatically restarted. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260106001228.1531146-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg

um: Preserve errno within signal handler

2026-01-13T18:39:09+00:00

We rely on errno to determine whether a syscall has failed, so we need to ensure that accessing errno is async-signal-safe. Currently, we preserve the errno in sig_handler_common(), but it doesn't cover every possible case. Let's do it in hard_handler() instead, which is the signal handler we actually register. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20260106001228.1531146-2-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg

um: Always set up AT_HWCAP and AT_PLATFORM

2025-11-06T12:02:34+00:00

Historically the code to set up AT_HWCAP and AT_PLATFORM was only built for 32bit x86 as it was intermingled with the vDSO passthrough code. Now that vDSO passthrough has been removed, always pass through AT_HWCAP and AT_PLATFORM. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-10-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg

x86/um: Do not inherit vDSO from host

2025-11-06T12:02:33+00:00

Inheriting the vDSO from the host is problematic. The values read from the time functions will not be correct for the UML kernel. Furthermore the start and end of the vDSO are not stable or detectable by userspace. Specifically the vDSO datapages start before AT_SYSINFO_EHDR and the vDSO itself is larger than a single page. This codepath is only used on 32bit x86 UML. In my testing with both 32bit and 64bit hosts the passthrough functionality has always been disabled anyways due to the checks against envp in scan_elf_aux(). Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-4-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg

um: Split out default elf_aux_hwcap

2025-11-06T12:02:33+00:00

Setting all auxiliary vector values to default values if one of them was not provided by the host will discard perfectly fine values. Remove the elf_aux_platform fallback from the vDSO ones. As zero is the correct fallback anyways, don't create a new conditional. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-3-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg

x86/um: Move ELF_PLATFORM fallback to x86-specific code

2025-11-06T12:02:33+00:00

The generic UM code should not have references to x86-specific value. Move the fallback into the x86-specific header. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-2-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg

um: Split out default elf_aux_platform

2025-11-06T12:02:32+00:00

Setting all auxiliary vector values to default values if one of them was not provided by the host will discard perfectly fine values. Move the elf_aux_platform fallback to its own conditional. Signed-off-by: Thomas Weißschuh Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-1-e930063eff5f@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: Define timers on a per-CPU basis

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

Define timers on a per-CPU basis to enable each CPU to have its own timer. This is a preparation for adding SMP support. Signed-off-by: Tiwei Bie Link: https://patch.msgid.link/20251027001815.1666872-5-tiwei.bie@linux.dev Signed-off-by: Johannes Berg