kernel/linux.git/arch/Kconfig, branch v6.1.168

Revert "mm: mmap: allow for the maximum number of bits for randomizing mmap_base by default"

2024-06-27T11:46:24+00:00

commit 14d7c92f8df9c0964ae6f8b813c1b3ac38120825 upstream. This reverts commit 3afb76a66b5559a7b595155803ce23801558a7a9. This was a wrongheaded workaround for an issue that had already been fixed much better by commit 4ef9ad19e176 ("mm: huge_memory: don't force huge page alignment on 32 bit"). Asking users questions at kernel compile time that they can't make sense of is not a viable strategy. And the fact that even the kernel VM maintainers apparently didn't catch that this "fix" is not a fix any more pretty much proves the point that people can't be expected to understand the implications of the question. It may well be the case that we could improve things further, and that __thp_get_unmapped_area() should take the mapping randomization into account even for 64-bit kernels. Maybe we should not be so eager to use THP mappings. But in no case should this be a kernel config option. Cc: Rafael Aquini Cc: Andrew Morton Cc: Jiri Slaby Cc: Suren Baghdasaryan Cc: Matthew Wilcox (Oracle) Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: mmap: allow for the maximum number of bits for randomizing mmap_base by default

2024-06-27T11:46:22+00:00

commit 3afb76a66b5559a7b595155803ce23801558a7a9 upstream. An ASLR regression was noticed [1] and tracked down to file-mapped areas being backed by THP in recent kernels. The 21-bit alignment constraint for such mappings reduces the entropy for randomizing the placement of 64-bit library mappings and breaks ASLR completely for 32-bit libraries. The reported issue is easily addressed by increasing vm.mmap_rnd_bits and vm.mmap_rnd_compat_bits. This patch just provides a simple way to set ARCH_MMAP_RND_BITS and ARCH_MMAP_RND_COMPAT_BITS to their maximum values allowed by the architecture at build time. [1] https://zolutal.github.io/aslrnt/ [akpm@linux-foundation.org: default to `y' if 32-bit, per Rafael] Link: https://lkml.kernel.org/r/20240606180622.102099-1-aquini@redhat.com Fixes: 1854bc6e2420 ("mm/readahead: Align file mappings for non-DAX") Signed-off-by: Rafael Aquini Cc: Arnd Bergmann Cc: Heiko Carstens Cc: Mike Rapoport (IBM) Cc: Paul E. McKenney Cc: Petr Mladek Cc: Samuel Holland Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

cpu: Re-enable CPU mitigations by default for !X86 architectures

2024-05-02T14:29:28+00:00

commit fe42754b94a42d08cf9501790afc25c4f6a5f631 upstream. Rename x86's to CPU_MITIGATIONS, define it in generic code, and force it on for all architectures exception x86. A recent commit to turn mitigations off by default if SPECULATION_MITIGATIONS=n kinda sorta missed that "cpu_mitigations" is completely generic, whereas SPECULATION_MITIGATIONS is x86-specific. Rename x86's SPECULATIVE_MITIGATIONS instead of keeping both and have it select CPU_MITIGATIONS, as having two configs for the same thing is unnecessary and confusing. This will also allow x86 to use the knob to manage mitigations that aren't strictly related to speculative execution. Use another Kconfig to communicate to common code that CPU_MITIGATIONS is already defined instead of having x86's menu depend on the common CPU_MITIGATIONS. This allows keeping a single point of contact for all of x86's mitigations, and it's not clear that other architectures *want* to allow disabling mitigations at compile-time. Fixes: f337a6a21e2f ("x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n") Closes: https://lkml.kernel.org/r/20240413115324.53303a68%40canb.auug.org.au Reported-by: Stephen Rothwell Reported-by: Michael Ellerman Reported-by: Geert Uytterhoeven Signed-off-by: Sean Christopherson Signed-off-by: Borislav Petkov (AMD) Acked-by: Josh Poimboeuf Acked-by: Borislav Petkov (AMD) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240420000556.2645001-2-seanjc@google.com Signed-off-by: Greg Kroah-Hartman

scs: add CONFIG_MMU dependency for vfree_atomic()

2024-02-23T08:12:32+00:00

commit 6f9dc684cae638dda0570154509884ee78d0f75c upstream. The shadow call stack implementation fails to build without CONFIG_MMU: ld.lld: error: undefined symbol: vfree_atomic >>> referenced by scs.c >>> kernel/scs.o:(scs_free) in archive vmlinux.a Link: https://lkml.kernel.org/r/20240122175204.2371009-1-samuel.holland@sifive.com Fixes: a2abe7cbd8fe ("scs: switch to vmapped shadow stacks") Signed-off-by: Samuel Holland Reviewed-by: Sami Tolvanen Cc: Will Deacon Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

cpu/SMT: Create topology_smt_thread_allowed()

2024-01-10T16:10:26+00:00

[ Upstream commit 38253464bc821d6de6bba81bb1412ebb36f6cbd1 ] Some architectures allows partial SMT states, i.e. when not all SMT threads are brought online. To support that, add an architecture helper which checks whether a given CPU is allowed to be brought online depending on how many SMT threads are currently enabled. Since this is only applicable to architecture supporting partial SMT, only these architectures should select the new configuration variable CONFIG_SMT_NUM_THREADS_DYNAMIC. For the other architectures, not supporting the partial SMT states, there is no need to define topology_cpu_smt_allowed(), the generic code assumed that all the threads are allowed or only the primary ones. Call the helper from cpu_smt_enable(), and cpu_smt_allowed() when SMT is enabled, to check if the particular thread should be onlined. Notably, also call it from cpu_smt_disable() if CPU_SMT_ENABLED, to allow offlining some threads to move from a higher to lower number of threads online. [ ldufour: Slightly reword the commit's description ] [ ldufour: Introduce CONFIG_SMT_NUM_THREADS_DYNAMIC ] Suggested-by: Thomas Gleixner Signed-off-by: Michael Ellerman Signed-off-by: Laurent Dufour Signed-off-by: Thomas Gleixner Tested-by: Zhang Rui Link: https://lore.kernel.org/r/20230705145143.40545-7-ldufour@linux.ibm.com Stable-dep-of: d91bdd96b55c ("cpu/SMT: Make SMT control more robust against enumeration failures") Signed-off-by: Sasha Levin

init: Provide arch_cpu_finalize_init()

2023-08-08T18:03:46+00:00

commit 7725acaa4f0c04fbefb0e0d342635b967bb7d414 upstream check_bugs() has become a dumping ground for all sorts of activities to finalize the CPU initialization before running the rest of the init code. Most are empty, a few do actual bug checks, some do alternative patching and some cobble a CPU advertisement string together.... Aside of that the current implementation requires duplicated function declaration and mostly empty header files for them. Provide a new function arch_cpu_finalize_init(). Provide a generic declaration if CONFIG_ARCH_HAS_CPU_FINALIZE_INIT is selected and a stub inline otherwise. This requires a temporary #ifdef in start_kernel() which will be removed along with check_bugs() once the architectures are converted over. Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230613224544.957805717@linutronix.de Signed-off-by: Daniel Sneddon Signed-off-by: Greg Kroah-Hartman

ftrace: Allow WITH_ARGS flavour of graph tracer with shadow call stack

2022-12-31T12:32:45+00:00

[ Upstream commit 38792972de4294163f44d6360fd221e6f2c22a05 ] The recent switch on arm64 from DYNAMIC_FTRACE_WITH_REGS to DYNAMIC_FTRACE_WITH_ARGS failed to take into account that we currently require the former in order to allow the function graph tracer to be enabled in combination with shadow call stacks. This means that this is no longer permitted at all, in spite of the fact that either flavour of ftrace works perfectly fine in this combination. So permit WITH_ARGS as well as WITH_REGS. Fixes: ddc9863e9e90 ("scs: Disable when function graph tracing is enabled") Acked-by: Mark Rutland Acked-by: Steven Rostedt (Google) Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20221213132407.1485025-1-ardb@kernel.org Signed-off-by: Will Deacon Signed-off-by: Sasha Levin

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04+00:00

Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...

Merge tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2022-10-04T00:11:07+00:00

Pull kcfi updates from Kees Cook: "This replaces the prior support for Clang's standard Control Flow Integrity (CFI) instrumentation, which has required a lot of special conditions (e.g. LTO) and work-arounds. The new implementation ("Kernel CFI") is specific to C, directly designed for the Linux kernel, and takes advantage of architectural features like x86's IBT. This series retains arm64 support and adds x86 support. GCC support is expected in the future[1], and additional "generic" architectural support is expected soon[2]. Summary: - treewide: Remove old CFI support details - arm64: Replace Clang CFI support with Clang KCFI support - x86: Introduce Clang KCFI support" Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107048 [1] Link: https://github.com/samitolvanen/llvm-project/commits/kcfi_generic [2] * tag 'kcfi-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (22 commits) x86: Add support for CONFIG_CFI_CLANG x86/purgatory: Disable CFI x86: Add types to indirectly called assembly functions x86/tools/relocs: Ignore __kcfi_typeid_ relocations kallsyms: Drop CONFIG_CFI_CLANG workarounds objtool: Disable CFI warnings objtool: Preserve special st_shndx indexes in elf_update_symbol treewide: Drop __cficanonical treewide: Drop WARN_ON_FUNCTION_MISMATCH treewide: Drop function_nocfi init: Drop __nocfi from __init arm64: Drop unneeded __nocfi attributes arm64: Add CFI error handling arm64: Add types to indirect called assembly functions psci: Fix the function type for psci_initcall_t lkdtm: Emit an indirect call for CFI tests cfi: Add type helper macros cfi: Switch to -fsanitize=kcfi cfi: Drop __CFI_ADDRESSABLE cfi: Remove CONFIG_CFI_CLANG_SHADOW ...

Kbuild: add Rust support

2022-09-28T07:02:20+00:00

Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Adam Bratschi-Kaye Signed-off-by: Adam Bratschi-Kaye Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Michael Ellerman Signed-off-by: Michael Ellerman Co-developed-by: Sven Van Asbroeck Signed-off-by: Sven Van Asbroeck Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boris-Chengbiao Zhou Signed-off-by: Boris-Chengbiao Zhou Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Co-developed-by: Douglas Su Signed-off-by: Douglas Su Co-developed-by: Dariusz Sosnowski Signed-off-by: Dariusz Sosnowski Co-developed-by: Antonio Terceiro Signed-off-by: Antonio Terceiro Co-developed-by: Daniel Xu Signed-off-by: Daniel Xu Co-developed-by: Björn Roy Baron Signed-off-by: Björn Roy Baron Co-developed-by: Martin Rodriguez Reboredo Signed-off-by: Martin Rodriguez Reboredo Signed-off-by: Miguel Ojeda