kernel/linux.git/arch/um/include, branch v6.6.132

um: Re-evaluate thread flags repeatedly

2025-08-28T14:28:21+00:00

[ Upstream commit b9e2f2246eb2b5617d53af7b5e4e1b8c916f26a8 ] The thread flags may change during their processing. For example a task_work can queue a new signal to be sent. This signal should be delivered before returning to usespace again. Evaluate the flags repeatedly similar to other architectures. Signed-off-by: Thomas Weißschuh Reviewed-by: Nam Cao Link: https://patch.msgid.link/20250704-uml-thread_flags-v1-1-0e293fd8d627@linutronix.de Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

um: Add cmpxchg8b_emu and checksum functions to asm-prototypes.h

2025-07-06T09:00:07+00:00

[ Upstream commit 674d03f6bd6b0f8327f1a4920ff5893557facfbd ] 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 Cc: linux-kbuild@vger.kernel.org Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202503251216.lE4t9Ikj-lkp@intel.com/ Signed-off-by: Sami Tolvanen Link: https://patch.msgid.link/20250326190500.847236-2-samitolvanen@google.com Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

um: remove copy_from_kernel_nofault_allowed

2025-04-10T12:37:34+00:00

[ Upstream commit 84a6fc378471fbeaf48f8604566a5a33a3d63c18 ] There is no need to override the default version of this function anymore as UML now has proper _nofault memory access functions. Doing this also fixes the fact that the implementation was incorrect as using mincore() will incorrectly flag pages as inaccessible if they were swapped out by the host. Fixes: f75b1b1bedfb ("um: Implement probe_kernel_read()") Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20250210160926.420133-3-benjamin@sipsolutions.net Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

um: Fix the declaration of kasan_map_memory

2024-06-12T09:12:42+00:00

[ Upstream commit 6a85e34c4d07d2ec0c153067baff338ac0db55ca ] Make it match its definition (size_t vs unsigned long). And declare it in a shared header to fix the -Wmissing-prototypes warning, as it is defined in the user code and called in the kernel code. Fixes: 5b301409e8bc ("UML: add support for KASAN under x86_64") Signed-off-by: Tiwei Bie Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um: Fix the -Wmissing-prototypes warning for get_thread_reg

2024-06-12T09:12:42+00:00

[ Upstream commit 3144013e48f4f6e5127223c4ebc488016815dedb ] The get_thread_reg function is defined in the user code, and is called by the kernel code. It should be declared in a shared header. Fixes: dbba7f704aa0 ("um: stop polluting the namespace with registers.h contents") Signed-off-by: Tiwei Bie Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um: Fix the -Wmissing-prototypes warning for __switch_mm

2024-06-12T09:12:42+00:00

[ Upstream commit 2cbade17b18c0f0fd9963f26c9fc9b057eb1cb3a ] The __switch_mm function is defined in the user code, and is called by the kernel code. It should be declared in a shared header. Fixes: 4dc706c2f292 ("um: take um_mmu.h to asm/mmu.h, clean asm/mmu_context.h a bit") Signed-off-by: Tiwei Bie Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

work around gcc bugs with 'asm goto' with outputs

2024-02-23T08:24:47+00:00

commit 4356e9f841f7fbb945521cef3577ba394c65f3fc upstream. We've had issues with gcc and 'asm goto' before, and we created a 'asm_volatile_goto()' macro for that in the past: see commits 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation bug") and a9f180345f53 ("compiler/gcc4: Make quirk for asm_volatile_goto() unconditional"). Then, much later, we ended up removing the workaround in commit 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR 58670") because we no longer supported building the kernel with the affected gcc versions, but we left the macro uses around. Now, Sean Christopherson reports a new version of a very similar problem, which is fixed by re-applying that ancient workaround. But the problem in question is limited to only the 'asm goto with outputs' cases, so instead of re-introducing the old workaround as-is, let's rename and limit the workaround to just that much less common case. It looks like there are at least two separate issues that all hit in this area: (a) some versions of gcc don't mark the asm goto as 'volatile' when it has outputs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 which is easy to work around by just adding the 'volatile' by hand. (b) Internal compiler errors: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 which are worked around by adding the extra empty 'asm' as a barrier, as in the original workaround. but the problem Sean sees may be a third thing since it involves bad code generation (not an ICE) even with the manually added 'volatile'. but the same old workaround works for this case, even if this feels a bit like voodoo programming and may only be hiding the issue. Reported-and-tested-by: Sean Christopherson Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ Cc: Nick Desaulniers Cc: Uros Bizjak Cc: Jakub Jelinek Cc: Andrew Pinski Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

um: Fix naming clash between UML and scheduler

2024-02-05T20:14:30+00:00

[ Upstream commit 541d4e4d435c8b9bfd29f70a1da4a2db97794e0a ] __cant_sleep was already used and exported by the scheduler. The name had to be changed to a UML specific one. Signed-off-by: Anton Ivanov Reviewed-by: Peter Lafreniere Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

Merge tag 'uml-for-linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

2023-09-04T18:32:21+00:00

Pull UML updates from Richard Weinberger: - Drop 32-bit checksum implementation and re-use it from arch/x86 - String function cleanup - Fixes for -Wmissing-variable-declarations and -Wmissing-prototypes builds * tag 'uml-for-linus-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: um: virt-pci: fix missing declaration warning um: Refactor deprecated strncpy to memcpy um: fix 3 instances of -Wmissing-prototypes um: port_kern: fix -Wmissing-variable-declarations uml: audio: fix -Wmissing-variable-declarations um: vector: refactor deprecated strncpy um: use obj-y to descend into arch/um/*/ um: Hard-code the result of 'uname -s' um: Use the x86 checksum implementation on 32-bit asm-generic: current: Don't include thread-info.h if building asm um: Remove unsued extern declaration ldt_host_info() um: Fix hostaudio build errors um: Remove strlcpy usage

Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2023-08-31T19:20:12+00:00

Pull x86 shadow stack support from Dave Hansen: "This is the long awaited x86 shadow stack support, part of Intel's Control-flow Enforcement Technology (CET). CET consists of two related security features: shadow stacks and indirect branch tracking. This series implements just the shadow stack part of this feature, and just for userspace. The main use case for shadow stack is providing protection against return oriented programming attacks. It works by maintaining a secondary (shadow) stack using a special memory type that has protections against modification. When executing a CALL instruction, the processor pushes the return address to both the normal stack and to the special permission shadow stack. Upon RET, the processor pops the shadow stack copy and compares it to the normal stack copy. For more information, refer to the links below for the earlier versions of this patch set" Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/ Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/ * tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits) x86/shstk: Change order of __user in type x86/ibt: Convert IBT selftest to asm x86/shstk: Don't retry vm_munmap() on -EINTR x86/kbuild: Fix Documentation/ reference x86/shstk: Move arch detail comment out of core mm x86/shstk: Add ARCH_SHSTK_STATUS x86/shstk: Add ARCH_SHSTK_UNLOCK x86: Add PTRACE interface for shadow stack selftests/x86: Add shadow stack test x86/cpufeatures: Enable CET CR4 bit for shadow stack x86/shstk: Wire in shadow stack interface x86: Expose thread features in /proc/$PID/status x86/shstk: Support WRSS for userspace x86/shstk: Introduce map_shadow_stack syscall x86/shstk: Check that signal frame is shadow stack mem x86/shstk: Check that SSP is aligned on sigreturn x86/shstk: Handle signals for shadow stack x86/shstk: Introduce routines modifying shstk x86/shstk: Handle thread shadow stack x86/shstk: Add user-mode shadow stack support ...