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2024-05-05rust: upgrade to Rust 1.78.0Miguel Ojeda1-1/+1
This is the next upgrade to the Rust toolchain, from 1.77.1 to 1.78.0 (i.e. the latest) [1]. See the upgrade policy [2] and the comments on the first upgrade in commit 3ed03f4da06e ("rust: upgrade to Rust 1.68.2"). It is much smaller than previous upgrades, since the `alloc` fork was dropped in commit 9d0441bab775 ("rust: alloc: remove our fork of the `alloc` crate") [3]. # Unstable features There have been no changes to the set of unstable features used in our own code. Therefore, the only unstable features allowed to be used outside the `kernel` crate is still `new_uninit`. However, since we finally dropped our `alloc` fork [3], all the unstable features used by `alloc` (~30 language ones, ~60 library ones) are not a concern anymore. This reduces the maintenance burden, increases the chances of new compiler versions working without changes and gets us closer to the goal of supporting several compiler versions. It also means that, ignoring non-language/library features, we are currently left with just the few language features needed to implement the kernel `Arc`, the `new_uninit` library feature, the `compiler_builtins` marker and the few `no_*` `cfg`s we pass when compiling `core`/`alloc`. Please see [4] for details. # Required changes ## LLVM's data layout Rust 1.77.0 (i.e. the previous upgrade) introduced a check for matching LLVM data layouts [5]. Then, Rust 1.78.0 upgraded LLVM's bundled major version from 17 to 18 [6], which changed the data layout in x86 [7]. Thus update the data layout in our custom target specification for x86 so that the compiler does not complain about the mismatch: error: data-layout for target `target-5559158138856098584`, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128`, differs from LLVM target's `x86_64-linux-gnu` default layout, `e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128` In the future, the goal is to drop the custom target specifications. Meanwhile, if we want to support other LLVM versions used in `rustc` (e.g. for LTO), we will need to add some extra logic (e.g. conditional on LLVM's version, or extracting the data layout from an existing built-in target specification). ## `unused_imports` Rust's `unused_imports` lint covers both unused and redundant imports. Now, in 1.78.0, the lint detects more cases of redundant imports [8]. Thus one of the previous patches cleaned them up. ## Clippy's `new_without_default` Clippy now suggests to implement `Default` even when `new()` is `const`, since `Default::default()` may call `const` functions even if it is not `const` itself [9]. Thus one of the previous patches implemented it. # Other changes in Rust Rust 1.78.0 introduced `feature(asm_goto)` [10] [11]. This feature was discussed in the past [12]. Rust 1.78.0 introduced `feature(const_refs_to_static)` [13] to allow referencing statics in constants and extended `feature(const_mut_refs)` to allow raw mutable pointers in constants. Together, this should cover the kernel's `VTABLE` use case. In fact, the implementation [14] in upstream Rust added a test case for it [15]. Rust 1.78.0 with debug assertions enabled (i.e. `-Cdebug-assertions=y`, kernel's `CONFIG_RUST_DEBUG_ASSERTIONS=y`) now always checks all unsafe preconditions, though without a way to opt-out for particular cases [16]. It would be ideal to have a way to selectively disable certain checks per-call site for this one (i.e. not just per check but for particular instances of a check), even if the vast majority of the checks remain in place [17]. Rust 1.78.0 also improved a couple issues we reported when giving feedback for the new `--check-cfg` feature [18] [19]. # `alloc` upgrade and reviewing As mentioned above, compiler upgrades will not update `alloc` anymore, since we dropped our `alloc` fork [3]. Link: https://github.com/rust-lang/rust/blob/stable/RELEASES.md#version-1780-2024-05-02 [1] Link: https://rust-for-linux.com/rust-version-policy [2] Link: https://lore.kernel.org/rust-for-linux/20240328013603.206764-1-wedsonaf@gmail.com/ [3] Link: https://github.com/Rust-for-Linux/linux/issues/2 [4] Link: https://github.com/rust-lang/rust/pull/120062 [5] Link: https://github.com/rust-lang/rust/pull/120055 [6] Link: https://reviews.llvm.org/D86310 [7] Link: https://github.com/rust-lang/rust/pull/117772 [8] Link: https://github.com/rust-lang/rust-clippy/pull/10903 [9] Link: https://github.com/rust-lang/rust/pull/119365 [10] Link: https://github.com/rust-lang/rust/issues/119364 [11] Link: https://lore.kernel.org/rust-for-linux/ZWipTZysC2YL7qsq@Boquns-Mac-mini.home/ [12] Link: https://github.com/rust-lang/rust/issues/119618 [13] Link: https://github.com/rust-lang/rust/pull/120932 [14] Link: https://github.com/rust-lang/rust/pull/120932/files#diff-e6fc1622c46054cd46b1d225c5386c5554564b3b0fa8a03c2dc2d8627a1079d9 [15] Link: https://github.com/rust-lang/rust/issues/120969 [16] Link: https://github.com/Rust-for-Linux/linux/issues/354 [17] Link: https://github.com/rust-lang/rust/pull/121202 [18] Link: https://github.com/rust-lang/rust/pull/121237 [19] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240401212303.537355-4-ojeda@kernel.org [ Added a few more details and links I mentioned in the list. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-03-15Merge tag 'arm64-upstream' of ↵Linus Torvalds1-1/+3
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Catalin Marinas: "The major features are support for LPA2 (52-bit VA/PA with 4K and 16K pages), the dpISA extension and Rust enabled on arm64. The changes are mostly contained within the usual arch/arm64/, drivers/perf, the arm64 Documentation and kselftests. The exception is the Rust support which touches some generic build files. Summary: - Reorganise the arm64 kernel VA space and add support for LPA2 (at stage 1, KVM stage 2 was merged earlier) - 52-bit VA/PA address range with 4KB and 16KB pages - Enable Rust on arm64 - Support for the 2023 dpISA extensions (data processing ISA), host only - arm64 perf updates: - StarFive's StarLink (integrates one or more CPU cores with a shared L3 memory system) PMU support - Enable HiSilicon Erratum 162700402 quirk for HIP09 - Several updates for the HiSilicon PCIe PMU driver - Arm CoreSight PMU support - Convert all drivers under drivers/perf/ to use .remove_new() - Miscellaneous: - Don't enable workarounds for "rare" errata by default - Clean up the DAIF flags handling for EL0 returns (in preparation for NMI support) - Kselftest update for ptrace() - Update some of the sysreg field definitions - Slight improvement in the code generation for inline asm I/O accessors to permit offset addressing - kretprobes: acquire regs via a BRK exception (previously done via a trampoline handler) - SVE/SME cleanups, comment updates - Allow CALL_OPS+CC_OPTIMIZE_FOR_SIZE with clang (previously disabled due to gcc silently ignoring -falign-functions=N)" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (134 commits) Revert "mm: add arch hook to validate mmap() prot flags" Revert "arm64: mm: add support for WXN memory translation attribute" Revert "ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512" ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512 kselftest/arm64: Add 2023 DPISA hwcap test coverage kselftest/arm64: Add basic FPMR test kselftest/arm64: Handle FPMR context in generic signal frame parser arm64/hwcap: Define hwcaps for 2023 DPISA features arm64/ptrace: Expose FPMR via ptrace arm64/signal: Add FPMR signal handling arm64/fpsimd: Support FEAT_FPMR arm64/fpsimd: Enable host kernel access to FPMR arm64/cpufeature: Hook new identification registers up to cpufeature docs: perf: Fix build warning of hisi-pcie-pmu.rst perf: starfive: Only allow COMPILE_TEST for 64-bit architectures MAINTAINERS: Add entry for StarFive StarLink PMU docs: perf: Add description for StarFive's StarLink PMU dt-bindings: perf: starfive: Add JH8100 StarLink PMU perf: starfive: Add StarLink PMU support docs: perf: Update usage for target filter of hisi-pcie-pmu ...
2024-02-14Merge branch 'x86/bugs' into x86/core, to pick up pending changes before ↵Ingo Molnar1-1/+1
dependent patches Merge in pending alternatives patching infrastructure changes, before applying more patches. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2024-02-09arm64: rust: Enable Rust support for AArch64Jamie Cunliffe1-1/+3
This commit provides the build flags for Rust for AArch64. The core Rust support already in the kernel does the rest. This enables the PAC ret and BTI options in the Rust build flags to match the options that are used when building C. The Rust samples have been tested with this commit. Signed-off-by: Jamie Cunliffe <Jamie.Cunliffe@arm.com> Acked-by: Will Deacon <will@kernel.org> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Fabien Parent <fabien.parent@linaro.org> Link: https://lore.kernel.org/r/20231020155056.3495121-3-Jamie.Cunliffe@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2024-01-17LoongArch: Enable initial Rust supportWANG Rui1-0/+7
Enable initial Rust support for LoongArch. Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: WANG Rui <wangrui@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-01-10x86/bugs: Rename CONFIG_RETPOLINE => CONFIG_MITIGATION_RETPOLINEBreno Leitao1-1/+1
Step 5/10 of the namespace unification of CPU mitigations related Kconfig options. [ mingo: Converted a few more uses in comments/messages as well. ] Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Ariel Miculas <amiculas@cisco.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231121160740.1249350-6-leitao@debian.org
2022-09-28x86: enable initial Rust supportMiguel Ojeda1-2/+13
Note that only x86_64 is covered and not all features nor mitigations are handled, but it is enough as a starting point and showcases the basics needed to add Rust support for a new architecture. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: David Gow <davidgow@google.com> Signed-off-by: David Gow <davidgow@google.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2022-09-28scripts: add `generate_rust_target.rs`Miguel Ojeda1-0/+171
This script takes care of generating the custom target specification file for `rustc`, based on the kernel configuration. It also serves as an example of a Rust host program. A dummy architecture is kept in this patch so that a later patch adds x86 support on top with as few changes as possible. Reviewed-by: Kees Cook <keescook@chromium.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: David Gow <davidgow@google.com> Signed-off-by: David Gow <davidgow@google.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>