apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets by japaric · Pull Request #155453 · rust-lang/rust

japaric · 2026-04-17T16:55:03Z

as it's done for other AArch64 targets

although the linker (GCC) may be configured to apply the fix by default it's preferred to have rustc pass the flag to the linker to ensure the mitigation is always applied

for example, the Arm GNU toolchain does not enable the errata mitigation by default (checked version: 13.3.Rel1)

see #118095 for background information

rustbot · 2026-04-17T16:55:07Z

These commits modify compiler targets.
(See the Target Tier Policy.)

rustbot · 2026-04-17T16:55:09Z

r? @wesleywiser

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wesleywiser

Seems reasonable to me

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wesleywiser · 2026-04-17T17:28:47Z

@rustbot ping arm

Objections to merging this?

rustbot · 2026-04-17T17:28:51Z

Hey ARM Group! This issue has been identified as a good "ARM candidate".
In case it's useful, here are some instructions for tackling these sorts of
issues. Maybe take a look?
Thanks! <3

cc @adamgemmell @davidtwco @hug-dev @Jamesbarford @joaopaulocarreiro @lqd @raw-bin @Stammark

as it's done for other AArch64 targets although the linker (GCC) _may_ be configured to apply the fix by default it's preferred to have rustc pass the flag to the linker to ensure the mitigation is always applied for example, the Arm GNU toolchain does _not_ enable the errata mitigation by default (checked version: 13.3.Rel1) see issue 118095 for background information cherry-picked from upstream, see rust-lang/rust#155453 for details re-enable the tests for this fix

adamgemmell · 2026-04-22T11:23:08Z

I'm happy with this, I think everything in Jacob's comment on the none target still applies. How would the user override this if they want to?

japaric · 2026-04-28T13:32:38Z

How would the user override this if they want to?

they can pass -mno-fix-cortex-a53-843419 to the linker driver (GCC) to opt-out of the silicon errata fix. that'd be passing -C link-arg=-mno-fix-cortex-a53-843419 to the binary-producing rustc invocation

however, according to my testing there seems to be priority issue with this change. -Wl,--fix-cortex-a53-843419 has higher priority than -mno-fix-cortex-a53-843419 so the fix is applied regardless of the -mno flag.

--no-fix-cortex-a53-843419 is not a valid flag (as of GNU LD 2.42) so -Wl,--no-fix-cortex-a53-843419 is not an option to opt out of the fix.

what that all means is that, to let the user opt out of the errata fix, we should use -mfix-cortex-a53-843419 in the target spec instead of the -Wl version. I have updated the commit to do that just now.

adamgemmell · 2026-04-28T13:48:09Z

Sounds good, thank you!

wesleywiser · 2026-04-29T16:40:22Z

@bors r+

rust-bors · 2026-04-29T16:40:25Z

📌 Commit 221687a has been approved by wesleywiser

It is now in the queue for this repository.

…wesleywiser apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets as it's done for other AArch64 targets although the linker (GCC) _may_ be configured to apply the fix by default it's preferred to have rustc pass the flag to the linker to ensure the mitigation is always applied for example, the Arm GNU toolchain does _not_ enable the errata mitigation by default (checked version: 13.3.Rel1) see rust-lang#118095 for background information

…uwer Rollup of 22 pull requests Successful merges: - #154149 (resolve: Extend `ambiguous_import_visibilities` deprecation lint to glob-vs-glob ambiguities) - #155189 (simd_reduce_min/max: remove float support) - #155453 (apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets) - #155562 (Add a missing `GenericTypeVisitable`, and avoid having interner traits for `FnSigKind` and `Abi`) - #155608 (rustc_middle: Implement the `partial_cmp` operation for `DefId`s) - #155721 (When archive format is wrong produce an error instead of ICE) - #155794 (privacy: share effective visibility initialization) - #155832 (c-variadic: more precise compatibility check in const-eval) - #155856 (std_detect: support detecting more features on aarch64 Windows) - #155861 (Suggest `[const] Trait` bounds in more places) - #155899 (`dlltool`: Set the working directory to workaround `--temp-prefix` bug) - #155916 (Update with new LLVM 22 target for `wasm32-wali-linux-musl` target) - #155935 (remap OUT_DIR paths to fix build script path leakage in crate metadata. ) - #155950 (use the new `//@ needs-asm-mnemonic: ret` more) - #155958 (ci(free-disk-space): remove more tools and fix warnings) - #155966 (miri subtree update) - #155711 (bump curl-sys and openssl-sys to support OpenSSL 4.0.x) - #155831 (Add `AcceptContext::expect_key_value`) - #155877 (Avoid misleading return-type note for foreign `Fn` callees) - #155949 (Update `opt_ast_lowering_delayed_lints` query to allow "stealing" lints, allowing to use `FnOnce` instead of `Fn`) - #155951 (Make `FlatMapInPlaceVec` an unsafe trait.) - #155967 (Fix `doc_cfg` feature for extern items)

JonathanBrouwer · 2026-04-29T21:50:24Z

@bors r-
#155976 (comment)

rust-bors · 2026-04-29T21:50:31Z

This pull request was unapproved.

This PR was contained in a rollup (#155976), which was unapproved.

View changes since this unapproval

japaric · 2026-05-11T18:52:34Z

#155976 (comment)

it appears that -mfix-cortex-a53-843419 is only supported in Clang v21+ and CI is using Clang v20 (released in 2025).

-Wl,--fix-cortex-a53-843419 would have better compatibility as, according to my testing, it's supported by GNU LD 2.32 (released in 2019) and, of course, the rust-lld shipped with the compiler. it would however not be possible to opt out from the errata if we use the -Wl version.

@adamgemmell thoughts on switching this back to -Wl? I'd think that the perf impact of that alternative is negligible as the errata workaround is applied in an scenario that rarely happens

…uwer Rollup of 12 pull requests Successful merges: - #157467 (stdarch subtree update) - #155453 (apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets) - #156798 (delegation: do not always generate first argument) - #157016 (add `extern "tail"` calling convention) - #157450 (mark `Encode`, `Decode`, `Mark` impls as `#[inline]`) - #148183 (rustdoc: Test & document `test_harness` code block attribute) - #157190 (Silence recursive RUSTC_LOG_FORMAT_JSON messages) - #157470 (Avoid ICE when emitting TargetMachine config errors) - #157474 (Forbid optimize(none) with inline(always) or inline.) - #157475 (Add a smoke test for the optimize attribute.) - #157479 (Warn when `#[macro_use]` or `#[macro_escape]` is used on the crate root) - #157486 (Remove unused attributes from issue-29485.rs.) Failed merges: - #157485 (Rename `errors.rs` file to `diagnostics.rs`)

…wesleywiser apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets as it's done for other AArch64 targets although the linker (GCC) _may_ be configured to apply the fix by default it's preferred to have rustc pass the flag to the linker to ensure the mitigation is always applied for example, the Arm GNU toolchain does _not_ enable the errata mitigation by default (checked version: 13.3.Rel1) see rust-lang#118095 for background information

@aapoalas

Rollup of 12 pull requests Successful merges: - #155453 (apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets) - #156798 (delegation: do not always generate first argument) - #157438 (rustdoc: don't link doc(hidden) associated type projections) - #157450 (mark `Encode`, `Decode`, `Mark` impls as `#[inline]`) - #148183 (rustdoc: Test & document `test_harness` code block attribute) - #157190 (Silence recursive RUSTC_LOG_FORMAT_JSON messages) - #157396 (Add @aapoalas to libs review rotation) - #157470 (Avoid ICE when emitting TargetMachine config errors) - #157474 (Forbid optimize(none) with inline(always) or inline.) - #157475 (Add a smoke test for the optimize attribute.) - #157479 (Warn when `#[macro_use]` or `#[macro_escape]` is used on the crate root) - #157486 (Remove unused attributes from issue-29485.rs.) Failed merges: - #157485 (Rename `errors.rs` file to `diagnostics.rs`)

@aapoalas

Rollup of 12 pull requests Successful merges: - #157467 (stdarch subtree update) - #155453 (apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets) - #156798 (delegation: do not always generate first argument) - #157438 (rustdoc: don't link doc(hidden) associated type projections) - #157450 (mark `Encode`, `Decode`, `Mark` impls as `#[inline]`) - #157190 (Silence recursive RUSTC_LOG_FORMAT_JSON messages) - #157396 (Add @aapoalas to libs review rotation) - #157470 (Avoid ICE when emitting TargetMachine config errors) - #157474 (Forbid optimize(none) with inline(always) or inline.) - #157475 (Add a smoke test for the optimize attribute.) - #157479 (Warn when `#[macro_use]` or `#[macro_escape]` is used on the crate root) - #157486 (Remove unused attributes from issue-29485.rs.) Failed merges: - #157485 (Rename `errors.rs` file to `diagnostics.rs`)

…wesleywiser apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets as it's done for other AArch64 targets although the linker (GCC) _may_ be configured to apply the fix by default it's preferred to have rustc pass the flag to the linker to ensure the mitigation is always applied for example, the Arm GNU toolchain does _not_ enable the errata mitigation by default (checked version: 13.3.Rel1) see rust-lang#118095 for background information

@aapoalas

Rollup of 12 pull requests Successful merges: - rust-lang/rust#157467 (stdarch subtree update) - rust-lang/rust#155453 (apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets) - rust-lang/rust#156798 (delegation: do not always generate first argument) - rust-lang/rust#157438 (rustdoc: don't link doc(hidden) associated type projections) - rust-lang/rust#157450 (mark `Encode`, `Decode`, `Mark` impls as `#[inline]`) - rust-lang/rust#157190 (Silence recursive RUSTC_LOG_FORMAT_JSON messages) - rust-lang/rust#157396 (Add @aapoalas to libs review rotation) - rust-lang/rust#157470 (Avoid ICE when emitting TargetMachine config errors) - rust-lang/rust#157474 (Forbid optimize(none) with inline(always) or inline.) - rust-lang/rust#157475 (Add a smoke test for the optimize attribute.) - rust-lang/rust#157479 (Warn when `#[macro_use]` or `#[macro_escape]` is used on the crate root) - rust-lang/rust#157486 (Remove unused attributes from issue-29485.rs.) Failed merges: - rust-lang/rust#157485 (Rename `errors.rs` file to `diagnostics.rs`)

rustc's aarch64-unknown-linux-gnu target spec passes `-Wl,--fix-cortex-a53-843419` to the linker (rust-lang/rust#155453), which zig's linker rejects with "unsupported linker arg". cargo-zigbuild 0.23.0 filters the argument out. The aarch64 release job only runs on release branches, so the toolchain update to nightly-2026-08-13 landed on main without exercising it.

ARM64-musl Docker builds fail with Rust 1.98 because the target now [passes `--fix-cortex-a53-843419`](rust-lang/rust#155453), which [`zig cc` rejects](rust-cross/cargo-zigbuild#451). Require and lock `cargo-zigbuild` 0.23.0, which includes the [upstream change to filter this flag](rust-cross/cargo-zigbuild#452). Keep the existing Zig linker, libc, startup objects, and stack defaults. This restores build compatibility without enabling the new Cortex-A53 erratum mitigation. --------- Co-authored-by: zaniebot <242828183+zaniebot@users.noreply.github.com> Co-authored-by: Zanie Blue <contact@zanie.dev> Co-authored-by: Zanie Blue <zanie@openai.com>

cargo-zigbuild 0.23.0 skips rustc's -Wl,--fix-cortex-a53-843419 for the aarch64 musl target (rust-lang/rust#155453), which zig 0.13.0's linker rejects; it also needs rustc 1.88+, hence the image bump from 1.85 to 1.88.

…in (#245) The 1.98 toolchain bump (#241) is green on every CI check and still breaks the image: `docker.yml` fires on tags and pushes to `main`, not on pull requests, so the first build to run it was v0.30.1's — and only the arm64 leg failed. Rust 1.98 passes `--fix-cortex-a53-843419` to the linker for aarch64 targets (rust-lang/rust#155453). Zig's linker rejects unknown arguments outright, so the wrapper cargo-zigbuild 0.22.3 generates fails with `unsupported linker arg: --fix-cortex-a53-843419` and `noadd` never links for aarch64-unknown-linux-musl. amd64 is unaffected — the argument is only emitted for aarch64. cargo-zigbuild 0.23.0 filters the argument in `filter_linker_arg` (rust-cross/cargo-zigbuild#452), alongside the two other arguments it already dropped for the same reason. The rest of the 0.22.3..0.23.0 range is a cargo-dist config update, a cargo-options bump, and dependabot commits. Zig stays on 0.14.1: the fix is in the wrapper, not the linker, and 0.15+ still brings the libc++-19 bindgen requirement this pin exists to avoid. Claude-Session: https://claude.ai/code/session_01RLF7TP74kER7Wcx8Th33qc Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Rust 1.98 (stable since 2026-08-18) started passing `-Wl,--fix-cortex-a53-843419` on every aarch64-linux target (rust-lang/rust#155453). zig 0.16's cc driver rejects it outright ("error: unsupported linker arg"), so the arm64 Docker cross-build died linking crc-fast. cargo-zigbuild filters the flag as of 0.23.0 (rust-cross/cargo-zigbuild#452), so pin that — and move taiki-e/install-action to v2.86.6, the first release whose manifest carries 0.23.0 (v2.82.0 tops out at 0.22.3 and would silently fall back to cargo-binstall). Reproduced locally with rustc 1.98.0 + zig 0.16.0: 0.22.3 fails on crc-fast with the exact CI error, 0.23.0 links a valid aarch64 ELF. - h2 0.4.15 -> 0.4.18 clears RUSTSEC-2026-0258; `cargo audit` is green again.

apiraino · 2026-08-24T12:21:26Z

FYI this flag seems to break compiling on Aarch64 with very old gcc 4.9.4
cc: @japaric

(unsure if this was somehow expected, just wanted to leave a note here in case it helps)

The linux-gnu native build broke on aarch64 after Rust 1.98.0 began passing -Wl,--fix-cortex-a53-843419 to the linker (rust-lang/rust#155453), which the pinned cargo-zigbuild 0.20.1 rejected. Lock the whole cross-compile toolchain rather than letting Rust float: a new .github/actions/install-toolchain composite action installs a pinned Rust (1.98.0) and, for linux-gnu targets only, a pinned zig 0.13.0 plus cargo-zigbuild 0.23.2 (0.23.0+ filters the arg). ci.yml and cd.yml now call it in a single step, replacing the separate submodule install-rust usage and the old install-zigbuild action. Also add .github/actions/** to CI's pull_request path filter so changes to composite actions trigger the workflow. Signed-off-by: Alex Le <alex.le@improving.com>

The linux-gnu native build broke on aarch64 after Rust 1.98.0 began passing -Wl,--fix-cortex-a53-843419 to the linker (rust-lang/rust#155453), which the pinned cargo-zigbuild 0.20.1 did not recognise. The real cause was an unpinned Rust (install-rust used toolchain: stable) drifting past a stale-but-pinned cross-compiler. Lock both sides: install Rust via dtolnay/rust-toolchain pinned to 1.98.0 in ci.yml and cd.yml, and install zig 0.13.0 plus cargo-zigbuild 0.23.2 (0.23.0+ filters the arg) through pip in the install-zigbuild action. The pip install pulls ziglang in as a dependency and cargo-zigbuild finds zig via python3 -m ziglang, so no zig binary needs to be on PATH. dtolnay's targets input adds the rustup target cargo-zigbuild needs, replacing the install-zigbuild rust-target input. Also add .github/actions/** to CI's pull_request path filter so changes to composite actions trigger the workflow. Signed-off-by: Alex Le <alex.le@improving.com>

The linux-gnu native build broke on aarch64 after Rust 1.98.0 began passing -Wl,--fix-cortex-a53-843419 to the linker (rust-lang/rust#155453), which the pinned cargo-zigbuild 0.20.1 did not recognise. The real cause was an unpinned Rust (install-rust used toolchain: stable) drifting past a stale-but-pinned cross-compiler. Lock both sides: install Rust via dtolnay/rust-toolchain pinned to 1.98.0 in ci.yml and cd.yml, and install zig 0.13.0 plus cargo-zigbuild 0.23.1 (0.23.0+ filters the arg) through pip in the install-zigbuild action. The pip install pulls ziglang in as a dependency and cargo-zigbuild finds zig via python3 -m ziglang, so no zig binary needs to be on PATH. dtolnay's targets input adds the rustup target cargo-zigbuild needs, replacing the install-zigbuild rust-target input. Also add .github/actions/** to CI's pull_request path filter so changes to composite actions trigger the workflow. Signed-off-by: Alex Le <alex.le@improving.com>

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japaric force-pushed the a53-linux-fix-errata branch from 9bafb16 to a88c30d Compare April 17, 2026 16:55

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rustbot added the O-Arm Target: 32-bit Arm processors (armv6, armv7, thumb...), including 64-bit Arm in AArch32 state label Apr 17, 2026

japaric force-pushed the a53-linux-fix-errata branch from a88c30d to 221687a Compare April 28, 2026 13:31

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JonathanBrouwer mentioned this pull request Apr 29, 2026

Rollup of 10 pull requests #155975

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Rollup of 22 pull requests #155976

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Rollup of 12 pull requests #157502

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Rollup of 12 pull requests #157504

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Rollup of 11 pull requests #157505

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rust-bors Bot merged commit 0c119ef into rust-lang:main Jun 5, 2026
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tshepang deleted the a53-linux-fix-errata branch June 9, 2026 04:39

aviramha mentioned this pull request Aug 16, 2026

fix(ci): bump cargo-zigbuild to 0.23.0 for aarch64 linux builds metalbear-co/mirrord#4723

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zaniebot mentioned this pull request Aug 21, 2026

Update cargo-zigbuild for Rust 1.98 Docker builds astral-sh/uv#21263

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jhugman mentioned this pull request Aug 21, 2026

napi: upgrade @napi-rs/cli to v3 and drop the rustc 1.97.1 pin jhugman/uniffi-bindgen-react-native#446

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jpmcb mentioned this pull request Aug 21, 2026

🔧 fix(ci): bump cargo-zigbuild to 0.23.0 to skip --fix-cortex-a53-843419 papercomputeco/tapesctl#75

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hgy59 mentioned this pull request Aug 21, 2026

Aarch64 broken with gcc not supporting --fix-cortex-a53-843419 linker flag #161486

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henry40408 mentioned this pull request Aug 23, 2026

fix(docker): bump cargo-zigbuild to 0.23.0 so the arm64 leg links again henry40408/noadd#245

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fix(ci): version lock Rust and zigbuild valkey-io/valkey-glide-ruby#298

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hubcio mentioned this pull request Aug 25, 2026

fix(ci): bump cargo-zigbuild so arm64 images link under Rust 1.98 apache/iggy#3963

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