aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/um
AgeCommit message (Collapse)AuthorFilesLines
2026-04-20Merge tag 'uml-for-7.1-rc1' of ↵Linus Torvalds2-2/+6
git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux 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
2026-04-05mm: convert do_brk_flags() to use vma_flags_tLorenzo Stoakes (Oracle)1-2/+2
In order to be able to do this, we need to change VM_DATA_DEFAULT_FLAGS and friends and update the architecture-specific definitions also. We then have to update some KSM logic to handle VMA flags, and introduce VMA_STACK_FLAGS to define the vma_flags_t equivalent of VM_STACK_FLAGS. We also introduce two helper functions for use during the time we are converting legacy flags to vma_flags_t values - vma_flags_to_legacy() and legacy_to_vma_flags(). This enables us to iteratively make changes to break these changes up into separate parts. We use these explicitly here to keep VM_STACK_FLAGS around for certain users which need to maintain the legacy vm_flags_t values for the time being. We are no longer able to rely on the simple VM_xxx being set to zero if the feature is not enabled, so in the case of VM_DROPPABLE we introduce VMA_DROPPABLE as the vma_flags_t equivalent, which is set to EMPTY_VMA_FLAGS if the droppable flag is not available. While we're here, we make the description of do_brk_flags() into a kdoc comment, as it almost was already. We use vma_flags_to_legacy() to not need to update the vm_get_page_prot() logic as this time. Note that in create_init_stack_vma() we have to replace the BUILD_BUG_ON() with a VM_WARN_ON_ONCE() as the tested values are no longer build time available. We also update mprotect_fixup() to use VMA flags where possible, though we have to live with a little duplication between vm_flags_t and vma_flags_t values for the time being until further conversions are made. While we're here, update VM_SPECIAL to be defined in terms of VMA_SPECIAL_FLAGS now we have vma_flags_to_legacy(). Finally, we update the VMA tests to reflect these changes. Link: https://lkml.kernel.org/r/d02e3e45d9a33d7904b149f5604904089fd640ae.1774034900.git.ljs@kernel.org Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> [SELinux] Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: "Borislav Petkov (AMD)" <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Kees Cook <kees@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Ondrej Mosnacek <omosnace@redhat.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Pedro Falcato <pfalcato@suse.de> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@armlinux.org.uk> Cc: Stephen Smalley <stephen.smalley.work@gmail.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Will Deacon <will@kernel.org> Cc: xu xin <xu.xin16@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-03-21x86/um: fix vDSO installationThomas Weißschuh1-2/+0
The generic vDSO installation logic used by 'make vdso_install' requires that $(vdso-install-y) is defined by the top-level architecture Makefile and that it contains a path relative to the root of the tree. For UML neither of these is satisfied. Move the definition of $(vdso-install-y) to a place which is included by the arch/um/Makefile and use the full relative path. Fixes: f1c2bb8b9964 ("um: implement a x86_64 vDSO") Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20260318-um-vdso-install-v1-1-26a4ca5c4210@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2026-03-21um: avoid struct sigcontext redefinition with muslMarcel W. Wysocki1-0/+6
mcontext.c includes both <sys/ucontext.h> and <asm/sigcontext.h>. With musl libc, this causes a struct sigcontext redefinition error: <sys/ucontext.h> pulls in musl's <bits/signal.h>, which defines struct sigcontext directly. The kernel's <asm/sigcontext.h> then provides a second, conflicting definition of the same struct. With glibc this does not conflict because glibc's signal headers source their struct sigcontext from the kernel's own UAPI headers, so the include guard in <asm/sigcontext.h> makes the second inclusion a no-op. mcontext.c does not actually use struct sigcontext by name -- it only needs the FP-state types (_fpstate, _xstate, etc.) that are defined in <asm/sigcontext.h> independently of the sigcontext struct. Temporarily rename sigcontext to __kernel_sigcontext during the inclusion of <asm/sigcontext.h> so that the kernel's definition does not collide with musl's. The #undef restores normal name resolution immediately afterward. No functional change with glibc; fixes the build with musl. Signed-off-by: Marcel W. Wysocki <maci.stgn@gmail.com> Link: https://patch.msgid.link/20260215142803.1455757-2-maci.stgn@gmail.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2026-01-09arch: um/x86: Select ARCH_SUPPORTS_ATOMIC_RMW for UML_X86Boqun Feng1-0/+1
x86 atomic instructions are used for um on UML_X86, therefore atomics on UML_X86 support native atomic RmW as x86 does, hence select ARCH_SUPPORTS_ATOMIC_RMW. Reviewed-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Acked-by: Richard Weinberger <richard@nod.at> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Link: https://patch.msgid.link/20260106034034.60074-1-boqun.feng@gmail.com
2025-11-06um: Always set up AT_HWCAP and AT_PLATFORMThomas Weißschuh2-6/+4
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 <linux@weissschuh.net> Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-10-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-11-06x86/um: Remove FIXADDR_USER_START and FIXADDR_USE_ENDThomas Weißschuh1-8/+0
There are no users left. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-9-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-11-06x86/um: Drop gate area handlingThomas Weißschuh2-52/+2
With the removal of the vDSO passthrough from the host, FIXADDR_USER_START is always 0 and the gate area setup code is dead. Remove it. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-5-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-11-06x86/um: Do not inherit vDSO from hostThomas Weißschuh4-106/+3
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 <linux@weissschuh.net> Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-4-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-11-06x86/um: Move ELF_PLATFORM fallback to x86-specific codeThomas Weißschuh1-1/+2
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 <linux@weissschuh.net> Link: https://patch.msgid.link/20251028-uml-remove-32bit-pseudo-vdso-v1-2-e930063eff5f@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27um: Enable SMP support on x86Tiwei Bie2-0/+11
Implement spinlock support for SMP on UML/x86, leveraging x86's spinlock implementation. In addition, to support SMP on CPUs that do not support CX8, some additional work is required. However, considering that such CPUs are already very outdated, and x86 is also removing support for them [1], let's enable SMP support only on CPUs that support CX8. [1] https://lore.kernel.org/lkml/20250515085708.2510123-1-mingo@kernel.org/ Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20251027001815.1666872-9-tiwei.bie@linux.dev Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27um: vdso: Remove getcpu support on x86Tiwei Bie2-24/+0
We are going to support SMP on UML/x86, so we can't hard code the CPU and NUMA node in __vdso_getcpu() anymore. Let's just remove it and let applications fall back to the syscall. Suggested-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20251027001815.1666872-7-tiwei.bie@linux.dev Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27x86/um/vdso: Drop VDSO64-y from MakefileThomas Weißschuh1-5/+2
This symbol is unnecessary, remove it. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-4-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27x86/um/vdso: Panic when vDSO can not be allocatedThomas Weißschuh1-11/+1
The vDSO address is added to the userspace auxiliary vectors even if the vDSO was not allocated. When accessing the page, userspace processes will crash. Enforce that the allocation works. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-3-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27x86/um/vdso: Use prototypes from generic vDSO headersThomas Weißschuh1-3/+1
The generic vDSO library provides a convenient header for the vDSO function prototypes, use it. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-2-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27x86/um/vdso: Fix prototype of clock_gettime()Thomas Weißschuh1-3/+3
The clock_gettime() system call takes a pointer to 'struct __kernel_timespec', not 'struct __kernel_old_timespec'. Right now this is not an issue as the vDSO never works with the actual struct but only passes it through to the kernel. Fix the prototype for consistency with the system call. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20251013-uml-vdso-cleanup-v1-1-a079c7adcc69@weissschuh.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27um: move asm-offsets generation into a single fileJohannes Berg1-18/+0
There's nothing subarch dependent here, and it's odd that includes need to be done in the subarch, and then entries defined in the common file. Simplify the whole thing from three files into one. Link: https://patch.msgid.link/20251007071452.367989-4-johannes@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-10-27um/hostfs: define HOSTFS_ATTR_* via asm-offsetsJohannes Berg1-0/+1
The HOSTFS_ATTR_* values were meant to be standalone for communication between hostfs's kernel and user code parts. However, it's easy to forget that HOSTFS_ATTR_* should be used even on the kernel side, and that wasn't consistently done. As a result, the values need to match ATTR_* values, which is not useful to maintain by hand. Instead, generate them via asm-offsets like other constants that UML needs in user-side code that aren't otherwise available in any header files that can be included there. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Reviewed-by: Hongbo Li <lihongbo22@huawei.com> Link: https://patch.msgid.link/20251007071452.367989-3-johannes@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-09-10um: Centralize stub size calculationsTiwei Bie2-2/+2
Currently, the stub size is calculated in multiple places. Define a macro that performs the calculation so that the code is easier to read and maintain. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-07-29Merge tag 'uml-for-linux-6.17-rc1' of ↵Linus Torvalds6-61/+3
git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux Pull uml updates from Johannes Berg: "Mostly cleanups, except: - dynamic addition of vfio passthrough devices - implementation of HAVE_SYSCALL_TRACEPOINTS" * tag 'uml-for-linux-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: Replace __ASSEMBLY__ with __ASSEMBLER__ in the usermode headers um: Stop tracking stub's PID via userspace_pid[] um: Remove the pid parameter of handle_trap() um: Use err consistently in userspace() um: vfio: Support adding devices via mconsole um: rtc: Avoid shadowing err in uml_rtc_start() um: Avoid redefining ARCH_HAS_CACHE_LINE_SIZE um: Make mm_list and mm_list_lock static um: Make unscheduled_userspace_iterations static um: Re-evaluate thread flags repeatedly um: simplify syscall header files um/ptrace: Implement HAVE_SYSCALL_TRACEPOINTS um/x86: Add system call table to header file um: virt-pci: Switch to msi_create_parent_irq_domain() um: virtio_pcidev: Rename UM_PCI_STAT_WAITING
2025-07-28Merge tag 'execve-v6.17' of ↵Linus Torvalds1-5/+5
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull execve updates from Kees Cook: - Introduce regular REGSET note macros arch-wide (Dave Martin) - Remove arbitrary 4K limitation of program header size (Yin Fengwei) - Reorder function qualifiers for copy_clone_args_from_user() (Dishank Jogi) * tag 'execve-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (25 commits) fork: reorder function qualifiers for copy_clone_args_from_user binfmt_elf: remove the 4k limitation of program header size binfmt_elf: Warn on missing or suspicious regset note names xtensa: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names um: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names x86/ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names sparc: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names sh: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names s390/ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names riscv: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names powerpc/ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names parisc: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names openrisc: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names nios2: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names MIPS: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names m68k: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names LoongArch: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names hexagon: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names csky: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names arm64: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names ...
2025-07-14um: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note namesDave Martin1-5/+5
Instead of having the core code guess the note name for each regset, use USER_REGSET_NOTE_TYPE() to pick the correct name from elf.h. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <kees@kernel.org> Cc: Akihiko Odaki <akihiko.odaki@daynix.com> Cc: linux-um@lists.infradead.org Cc: x86@kernel.org Acked-by: Johannes Berg <johannes@sipsolutions.net> Tested-by: Johannes Berg <johannes@sipsolutions.net> Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp> Link: https://lore.kernel.org/r/20250701135616.29630-22-Dave.Martin@arm.com Signed-off-by: Kees Cook <kees@kernel.org>
2025-07-13um: Stop tracking stub's PID via userspace_pid[]Tiwei Bie1-1/+1
The PID of the stub process can be obtained from current_mm_id(). There is no need to track it via userspace_pid[]. Stop doing that to simplify the code. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20250711065021.2535362-4-tiwei.bie@linux.dev Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-07-11um: simplify syscall header filesJohannes Berg4-60/+0
Since Thomas's recent commit 2af10530639b ("um/x86: Add system call table to header file") , we now have two extern declarations of the syscall table, one internal and one external, and they don't even match on 32-bit. Clean this up and remove all the extra code. Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Link: https://patch.msgid.link/20250704141243.a68366f6acc3.If8587a4aafdb90644fc6d0b2f5e31a2d1887915f@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-07-11um/x86: Add system call table to header fileThomas Weißschuh1-0/+2
The generic system call tracing infrastructure requires access to the system call table. The symbol is already visible to the linker but is lacking a public declaration. Add a public declaration. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Reviewed-by: Nam Cao <namcao@linutronix.de> Link: https://patch.msgid.link/20250703-uml-have_syscall_tracepoints-v1-1-23c1d3808578@linutronix.de Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-06-25um: Use correct data source in fpregs_legacy_set()Tiwei Bie1-1/+1
Read from the buffer pointed to by 'from' instead of '&buf', as 'buf' contains no valid data when 'ubuf' is NULL. Fixes: b1e1bd2e6943 ("um: Add helper functions to get/set state for SECCOMP") Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20250606124428.148164-5-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-06-05Merge tag 'uml-for-linux-6.16-rc1' of ↵Linus Torvalds11-31/+366
git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux Pull UML updates from Johannes Berg: "The only really new thing is the long-standing seccomp work (originally from 2021!). Wven if it still isn't enabled by default due to security concerns it can still be used e.g. for tests. - remove obsolete network transports - remove PCI IO port support - start adding seccomp-based process handling instead of ptrace" * tag 'uml-for-linux-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (29 commits) um: remove "extern" from implementation of sigchld_handler um: fix unused variable warning um: fix SECCOMP 32bit xstate register restore um: pass FD for memory operations when needed um: Add SECCOMP support detection and initialization um: Implement kernel side of SECCOMP based process handling um: Track userspace children dying in SECCOMP mode um: Add helper functions to get/set state for SECCOMP um: Add stub side of SECCOMP/futex based process handling um: Move faultinfo extraction into userspace routine um: vector: Use mac_pton() for MAC address parsing um: vector: Clean up and modernize log messages um: chan_kern: use raw spinlock for irqs_to_free_lock MAINTAINERS: remove obsolete file entry in TUN/TAP DRIVER um: Fix tgkill compile error on old host OSes um: stop using PCI port I/O um: Remove legacy network transport infrastructure um: vector: Eliminate the dependency on uml_net um: Remove obsolete legacy network transports um/asm: Replace "REP; NOP" with PAUSE mnemonic ...
2025-06-05um: fix unused variable warningBenjamin Berg1-3/+0
The code was updated to access the PID of the userspace stub process in a different way, making the local cpu variable obsolete. Remove it. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202506050008.AwXLNxQX-lkp@intel.com/ Fixes: 406d17c6c370 ("um: Implement kernel side of SECCOMP based process handling") Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250605050325.1077208-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-06-04um: fix SECCOMP 32bit xstate register restoreBenjamin Berg1-1/+1
There was a typo that caused the extended FP state to be copied into the wrong location on 32 bit. On 32 bit we only store the xstate internally as that already contains everything. However, for compatibility, the mcontext on 32 bit first contains the legacy FP state and then the xstate. The code copied the xstate on top of the legacy FP state instead of using the correct offset. This offset was already calculated in the xstate_* variables, so simply switch to those to fix the problem. With this SECCOMP mode works on 32 bit, so lift the restriction. Fixes: b1e1bd2e6943 ("um: Add helper functions to get/set state for SECCOMP") Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250604081705.934112-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-06-02um: Implement kernel side of SECCOMP based process handlingBenjamin Berg2-4/+21
This adds the kernel side of the seccomp based process handling. Co-authored-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250602130052.545733-6-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-06-02um: Add helper functions to get/set state for SECCOMPBenjamin Berg3-20/+283
When not using ptrace, we need to both save and restore registers through the mcontext as provided by the host kernel to our signal handlers. Add corresponding functions to store the state to an mcontext and helpers to access the mcontext of the subprocess through the stub data. Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250602130052.545733-4-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-06-02um: Add stub side of SECCOMP/futex based process handlingBenjamin Berg4-0/+55
This adds the stub side for the new seccomp process management code. In this case we do register save/restore through the signal handler mcontext. Add special code for handling TLS, which for x86_64 means setting the FS_BASE/GS_BASE registers while for i386 it means calling the set_thread_area syscall. Co-authored-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250602130052.545733-3-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-05-05um/asm: Replace "REP; NOP" with PAUSE mnemonicUros Bizjak1-2/+2
Current minimum required version of binutils is 2.25, which supports PAUSE instruction mnemonic. Replace "REP; NOP" with this proper mnemonic. No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: David Laight <david.laight.linux@gmail.com> Link: https://patch.msgid.link/20250418083436.133148-2-ubizjak@gmail.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-05-05um/asm: Rename rep_nop() to native_pause()Uros Bizjak1-2/+2
Rename rep_nop() function to what it really does. No functional change intended. Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: David Laight <david.laight.linux@gmail.com> Link: https://patch.msgid.link/20250418083436.133148-1-ubizjak@gmail.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-05-05um: Add cmpxchg8b_emu and checksum functions to asm-prototypes.hSami Tolvanen1-0/+3
With CONFIG_GENDWARFKSYMS, um builds fail due to missing prototypes in asm/asm-prototypes.h. Add declarations for cmpxchg8b_emu and the exported checksum functions, including csum_partial_copy_generic as it's also exported. Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: linux-kbuild@vger.kernel.org Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202503251216.lE4t9Ikj-lkp@intel.com/ Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Link: https://patch.msgid.link/20250326190500.847236-2-samitolvanen@google.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-05-05um: fix _nofault accessesJohannes Berg2-2/+2
Nathan reported [1] that when built with clang, the um kernel crashes pretty much immediately. This turned out to be an issue with the inline assembly I had added, when clang used %rax/%eax for both operands. Reorder it so current->thread.segv_continue is written first, and then the lifetime of _faulted won't have overlap with the lifetime of segv_continue. In the email thread Benjamin also pointed out that current->mm is only NULL for true kernel tasks, but we could do this for a userspace task, so the current->thread.segv_continue logic must be lifted out of the mm==NULL check. Finally, while looking at this, put a barrier() so the NULL assignment to thread.segv_continue cannot be reorder before the possibly faulting operation. Reported-by: Nathan Chancellor <nathan@kernel.org> Closes: https://lore.kernel.org/r/20250402221254.GA384@ax162 [1] Fixes: d1d7f01f7cd3 ("um: mark rodata read-only and implement _nofault accesses") Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-03-18um: x86: clean up elf specific definitionsHajime Tazaki1-24/+0
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 <thehajime@gmail.com> Link: https://patch.msgid.link/2d70a0ed79ee0a0bef80ad4790063f4833dd9bed.1737348399.git.thehajime@gmail.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-03-18um: Store full CSGSFS and SS register from mcontextBenjamin Berg1-2/+1
Doing this allows using registers as retrieved from an mcontext to be pushed to a process using PTRACE_SETREGS. It is not entirely clear to me why CSGSFS was masked. Doing so creates issues when using the mcontext as process state in seccomp and simply copying the register appears to work perfectly fine for ptrace. Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net> Link: https://patch.msgid.link/20250224181827.647129-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-03-18um/locking: Remove semicolon from "lock" prefixUros Bizjak1-3/+3
Minimum version of binutils required to compile the kernel is 2.25. This version correctly handles the "lock" prefix, so it is possible to remove the semicolon, which was used to support ancient versions of GNU as. Due to the semicolon, the compiler considers "lock; insn" as two separate instructions. Removing the semicolon makes asm length calculations more accurate, consequently making scheduling and inlining decisions of the compiler more accurate. Removing the semicolon also enables assembler checks involving lock prefix. Trying to assemble e.g. "lock andl %eax, %ebx" results in: Error: expecting lockable instruction after `lock' Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://patch.msgid.link/20250228090058.2499163-1-ubizjak@gmail.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-03-18um: Allocate vdso page pointer staticallyTiwei Bie1-14/+3
Instead of dynamically allocating the pointer to the vdso page during boot, we can just allocate it statically. Doing so will reduce error handling and make the code slightly more readable. Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20250212045756.164977-1-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-03-18um: mark rodata read-only and implement _nofault accessesJohannes Berg3-0/+36
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 <johannes.berg@intel.com> Co-developed-by: Benjamin Berg <benjamin.berg@intel.com> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250210160926.420133-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-02-12um: properly align signal stack on x86_64Benjamin Berg1-3/+5
The stack needs to be properly aligned so 16 byte memory accesses on the stack are correct. This was broken when introducing the dynamic math register sizing as the rounding was not moved appropriately. Fixes: 3f17fed21491 ("um: switch to regset API and depend on XSTATE") Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20250107133509.265576-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2025-02-12um: add back support for FXSAVE registersBenjamin Berg2-3/+23
It was reported that qemu may not enable the XSTATE CPU extension, which is a requirement after commit 3f17fed21491 ("um: switch to regset API and depend on XSTATE"). Add a fallback to use FXSAVE (FP registers on x86_64 and XFP on i386) which is just a shorter version of the same data. The only difference is that the XSTATE magic should not be set in the signal frame. Note that this still drops support for the older i386 FP register layout as supporting this would require more backward compatibility to build a correct signal frame. Fixes: 3f17fed21491 ("um: switch to regset API and depend on XSTATE") Reported-by: SeongJae Park <sj@kernel.org> Closes: https://lore.kernel.org/r/20241203070218.240797-1-sj@kernel.org Tested-by: SeongJae Park <sj@kernel.org> Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20241204074827.1582917-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2025-01-13um: Remove unused asm/archparam.h headerTiwei Bie1-20/+0
This header is no longer used after the removal of fixmap support in commit 5bfc4a3a0af3 ("um: Remove obsolete fixmap support"). Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20250113153218.3331321-3-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2025-01-10um: Remove unused user_context functionTiwei Bie1-2/+0
It's no longer used since commit 6aa802ce6acc ("uml: throw out CHOOSE_MODE"). Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com> Link: https://patch.msgid.link/20241128083137.2219830-10-tiwei.btw@antgroup.com Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-11-07um: fix sparse warnings in signal codeBenjamin Berg1-6/+6
sparse reports that various places were missing the __user tag in casts. In addition, one location was using 0 instead of NULL. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20241031142017.430420-2-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-11-07um: fix sparse warnings from regset refactorBenjamin Berg2-6/+9
Some variables were not tagged with __user and another was not marked as static even though it should be. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202410280655.gOlEFwdG-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202410281821.WSPsAwq7-lkp@intel.com/ Fixes: 3f17fed21491 ("um: switch to regset API and depend on XSTATE") Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20241031142017.430420-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-10-23um: switch to regset API and depend on XSTATEBenjamin Berg13-454/+449
The PTRACE_GETREGSET API has now existed since Linux 2.6.33. The XSAVE CPU feature should also be sufficiently common to be able to rely on it. With this, define our internal FP state to be the hosts XSAVE data. Add discovery for the hosts XSAVE size and place the FP registers at the end of task_struct so that we can adjust the size at runtime. Next we can implement the regset API on top and update the signal handling as well as ptrace APIs to use them. Also switch coredump creation to use the regset API and finally set HAVE_ARCH_TRACEHOOK. This considerably improves the signal frames. Previously they might not have contained all the registers (i386) and also did not have the sizes and magic values set to the correct values to permit userspace to decode the frame. As a side effect, this will permit UML to run on hosts with newer CPU extensions (such as AMX) that need even more register state. Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Link: https://patch.msgid.link/20241023094120.4083426-1-benjamin@sipsolutions.net Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-10-23um: vdso: Always reject undefined references in during linkingThomas Weißschuh2-14/+2
Instead of using a custom script to detect and fail on undefined references, use --no-undefined for all VDSO linker invocations. Drop the now unused checkundef.sh script. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Link: https://patch.msgid.link/20241011-vdso-checkundef-v1-2-1a46e0352d20@linutronix.de Signed-off-by: Johannes Berg <johannes.berg@intel.com>
2024-10-23um: make stub_exe _start() pure inline asmJohannes Berg2-0/+16
Since __attribute__((naked)) cannot be used with functions containing C statements, just generate the few instructions it needs in assembly directly. While at it, fix the stack usage ("1 + 2*x - 1" is odd) and document what it must do, and why it must adjust the stack. Fixes: 8508a5e0e9db ("um: Fix misaligned stack in stub_exe") Link: https://lore.kernel.org/linux-um/CABVgOSntH-uoOFMP5HwMXjx_f1osMnVdhgKRKm4uz6DFm2Lb8Q@mail.gmail.com/ Reviewed-by: David Gow <davidgow@google.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
generated by cgit