Rollup merge of #127021 - thesummer:1-add-target-support-for-rtems-arm-xilinx-zedboard, r=tgross35

Add target support for RTEMS Arm

# `armv7-rtems-eabihf`

This PR adds a new target for the RTEMS RTOS. To get things started it focuses on Xilinx/AMD Zynq-based targets, but in theory it should also support other armv7-based board support packages in the future.
Given that RTEMS has support for many POSIX functions it is mostly enabling corresponding unix features for the new target.
I also previously started a PR in libc (https://github.com/rust-lang/libc/pull/3561) to add the needed OS specific C-bindings and was told that a PR in this repo is needed first. I will update the PR to the newest version after approval here.
I will probably also need to change one line in the backtrace repo.

Current status is that I could compile rustc for the new target locally (with the updated libc and backtrace) and could compile binaries, link, and execute a simple "Hello World" RTEMS application for the target hardware.

> A proposed target or target-specific patch that substantially changes code shared with other targets (not just target-specific code) must be reviewed and approved by the appropriate team for that shared code before acceptance.

There should be no breaking changes for existing targets. Main changes are adding corresponding `cfg` switches for the RTEMS OS and adding the C binding in libc.

# Tier 3 target policy

> - A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)

I will do the maintenance (for now) further members of the RTEMS community will most likely join once the first steps have been done.

> - Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
>     - Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
>     - If possible, use only letters, numbers, dashes and underscores for the name. Periods (`.`) are known to cause issues in Cargo.

The proposed triple is `armv7-rtems-eabihf`

> - Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
>     - The target must not introduce license incompatibilities.
>     - Anything added to the Rust repository must be under the standard Rust license (`MIT OR Apache-2.0`).
>     - The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the `tidy` tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
>     - Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, `rustc` built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
>     - "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are _not_ limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.

The tools consists of the cross-compiler toolchain (gcc-based). The RTEMS kernel (BSD license) and parts of the driver stack of FreeBSD (BSD license). All tools are FOSS and publicly available here: https://gitlab.rtems.org/rtems
There are also no new features or dependencies introduced to the Rust code.

> - Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.

N/A to me. I am not a reviewer nor Rust team member.

> - Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (`core` for most targets, `alloc` for targets that can support dynamic memory allocation, `std` for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.

`core` and `std` compile. Some advanced features of the `std` lib might not work yet. However, the goal of this tier 3 target it to make it easier for other people to build and run test applications to better identify the unsupported features and work towards enabling them.

> - The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.

Building is described in platform support doc. Running simple unit tests works. Running the test suite of the stdlib is currently not that easy. Trying to work towards that after the this target has been added to the nightly.

> - Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via ````@`)``` to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.

Understood.

>     - Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.

Ok

> - Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
>     - In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.

I think, I didn't add any breaking changes for any existing targets (see the comment regarding features above).

> - Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target.

Can produce assembly code via the llvm backend (tested on Linux).

>
> If a tier 3 target stops meeting these requirements, or the target maintainers no longer have interest or time, or the target shows no signs of activity and has not built for some time, or removing the target would improve the quality of the Rust codebase, we may post a PR to remove it; any such PR will be CCed to the target maintainers (and potentially other people who have previously worked on the target), to check potential interest in improving the situation.GIAt this tier, the Rust project provides no official support for a target, so we place minimal requirements on the introduction of targets.

Understood.

r? compiler-team

compiler/rustc_target/src/spec/mod.rs

@@ -1695,6 +1695,8 @@ supported_targets! {
     ("armv7r-none-eabihf", armv7r_none_eabihf),
     ("armv8r-none-eabihf", armv8r_none_eabihf),
 
+    ("armv7-rtems-eabihf", armv7_rtems_eabihf),
+
     ("x86_64-pc-solaris", x86_64_pc_solaris),
     ("sparcv9-sun-solaris", sparcv9_sun_solaris),
 

compiler/rustc_target/src/spec/targets/armv7_rtems_eabihf.rs

@@ -0,0 +1,35 @@
+use crate::spec::{cvs, Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel, Target, TargetOptions};
+
+pub(crate) fn target() -> Target {
+    Target {
+        llvm_target: "armv7-unknown-none-eabihf".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: Some("Armv7 RTEMS (Requires RTEMS toolchain and kernel".into()),
+            tier: Some(3),
+            host_tools: Some(false),
+            std: Some(true),
+        },
+        pointer_width: 32,
+        data_layout: "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64".into(),
+        arch: "arm".into(),
+
+        options: TargetOptions {
+            os: "rtems".into(),
+            families: cvs!["unix"],
+            abi: "eabihf".into(),
+            linker_flavor: LinkerFlavor::Gnu(Cc::Yes, Lld::No),
+            linker: None,
+            relocation_model: RelocModel::Static,
+            panic_strategy: PanicStrategy::Abort,
+            features: "+thumb2,+neon,+vfp3".into(),
+            max_atomic_width: Some(64),
+            emit_debug_gdb_scripts: false,
+            // GCC defaults to 8 for arm-none here.
+            c_enum_min_bits: Some(8),
+            eh_frame_header: false,
+            no_default_libraries: false,
+            env: "newlib".into(),
+            ..Default::default()
+        },
+    }
+}

library/core/Cargo.toml

@@ -43,6 +43,8 @@ check-cfg = [
     'cfg(bootstrap)',
     'cfg(no_fp_fmt_parse)',
     'cfg(stdarch_intel_sde)',
+    # #[cfg(bootstrap)] rtems
+    'cfg(target_os, values("rtems"))',
     # core use #[path] imports to portable-simd `core_simd` crate
     # and to stdarch `core_arch` crate which messes-up with Cargo list
     # of declared features, we therefor expect any feature cfg

library/core/src/ffi/mod.rs

@@ -110,7 +110,7 @@ mod c_char_definition {
             all(target_os = "android", any(target_arch = "aarch64", target_arch = "arm")),
             all(target_os = "l4re", target_arch = "x86_64"),
             all(
-                any(target_os = "freebsd", target_os = "openbsd"),
+                any(target_os = "freebsd", target_os = "openbsd", target_os = "rtems"),
                 any(
                     target_arch = "aarch64",
                     target_arch = "arm",

library/panic_unwind/Cargo.toml

@@ -20,3 +20,10 @@ cfg-if = { version = "1.0", features = ['rustc-dep-of-std'] }
 
 [target.'cfg(not(all(windows, target_env = "msvc")))'.dependencies]
 libc = { version = "0.2", default-features = false }
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    # #[cfg(bootstrap)] rtems
+    'cfg(target_os, values("rtems"))',
+]

library/panic_unwind/src/lib.rs

@@ -48,7 +48,7 @@ cfg_if::cfg_if! {
         target_os = "psp",
         target_os = "xous",
         target_os = "solid_asp3",
-        all(target_family = "unix", not(target_os = "espidf")),
+        all(target_family = "unix", not(any(target_os = "espidf", target_os = "rtems"))),
         all(target_vendor = "fortanix", target_env = "sgx"),
         target_family = "wasm",
     ))] {

library/std/Cargo.toml

@@ -146,4 +146,6 @@ check-cfg = [
     # and to the `backtrace` crate which messes-up with Cargo list
     # of declared features, we therefor expect any feature cfg
     'cfg(feature, values(any()))',
+    # #[cfg(bootstrap)] rtems
+    'cfg(target_os, values("rtems"))',
 ]

library/std/build.rs

@@ -53,6 +53,7 @@ fn main() {
         || target_os == "uefi"
         || target_os == "teeos"
         || target_os == "zkvm"
+        || target_os == "rtems"
 
         // See src/bootstrap/src/core/build_steps/synthetic_targets.rs
         || env::var("RUSTC_BOOTSTRAP_SYNTHETIC_TARGET").is_ok()

library/std/src/os/mod.rs

@@ -143,6 +143,8 @@ pub mod nto;
 pub mod openbsd;
 #[cfg(target_os = "redox")]
 pub mod redox;
+#[cfg(target_os = "rtems")]
+pub mod rtems;
 #[cfg(target_os = "solaris")]
 pub mod solaris;
 #[cfg(target_os = "solid_asp3")]

library/std/src/os/rtems/fs.rs

@@ -0,0 +1,374 @@
+#![stable(feature = "metadata_ext", since = "1.1.0")]
+
+use crate::fs::Metadata;
+use crate::sys_common::AsInner;
+
+/// OS-specific extensions to [`fs::Metadata`].
+///
+/// [`fs::Metadata`]: crate::fs::Metadata
+#[stable(feature = "metadata_ext", since = "1.1.0")]
+pub trait MetadataExt {
+    /// Returns the device ID on which this file resides.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_dev());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_dev(&self) -> u64;
+
+    /// Returns the inode number.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_ino());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ino(&self) -> u64;
+
+    /// Returns the file type and mode.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_mode());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mode(&self) -> u32;
+
+    /// Returns the number of hard links to file.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_nlink());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_nlink(&self) -> u64;
+
+    /// Returns the user ID of the file owner.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_uid());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_uid(&self) -> u32;
+
+    /// Returns the group ID of the file owner.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_gid());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_gid(&self) -> u32;
+
+    /// Returns the device ID that this file represents. Only relevant for special file.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_rdev());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_rdev(&self) -> u64;
+
+    /// Returns the size of the file (if it is a regular file or a symbolic link) in bytes.
+    ///
+    /// The size of a symbolic link is the length of the pathname it contains,
+    /// without a terminating null byte.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_size());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_size(&self) -> u64;
+
+    /// Returns the last access time of the file, in seconds since Unix Epoch.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_atime());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_atime(&self) -> i64;
+
+    /// Returns the last access time of the file, in nanoseconds since [`st_atime`].
+    ///
+    /// [`st_atime`]: Self::st_atime
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_atime_nsec());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_atime_nsec(&self) -> i64;
+
+    /// Returns the last modification time of the file, in seconds since Unix Epoch.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_mtime());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mtime(&self) -> i64;
+
+    /// Returns the last modification time of the file, in nanoseconds since [`st_mtime`].
+    ///
+    /// [`st_mtime`]: Self::st_mtime
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_mtime_nsec());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_mtime_nsec(&self) -> i64;
+
+    /// Returns the last status change time of the file, in seconds since Unix Epoch.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_ctime());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ctime(&self) -> i64;
+
+    /// Returns the last status change time of the file, in nanoseconds since [`st_ctime`].
+    ///
+    /// [`st_ctime`]: Self::st_ctime
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_ctime_nsec());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_ctime_nsec(&self) -> i64;
+
+    /// Returns the "preferred" block size for efficient filesystem I/O.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_blksize());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_blksize(&self) -> u64;
+
+    /// Returns the number of blocks allocated to the file, 512-byte units.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::fs;
+    /// use std::io;
+    /// use std::os::rtems::fs::MetadataExt;
+    ///
+    /// fn main() -> io::Result<()> {
+    ///     let meta = fs::metadata("some_file")?;
+    ///     println!("{}", meta.st_blocks());
+    ///     Ok(())
+    /// }
+    /// ```
+    #[stable(feature = "metadata_ext2", since = "1.8.0")]
+    fn st_blocks(&self) -> u64;
+}
+
+#[stable(feature = "metadata_ext", since = "1.1.0")]
+impl MetadataExt for Metadata {
+    fn st_dev(&self) -> u64 {
+        self.as_inner().as_inner().st_dev as u64
+    }
+
+    fn st_ino(&self) -> u64 {
+        self.as_inner().as_inner().st_ino as u64
+    }
+
+    fn st_mode(&self) -> u32 {
+        self.as_inner().as_inner().st_mode as u32
+    }
+
+    fn st_nlink(&self) -> u64 {
+        self.as_inner().as_inner().st_nlink as u64
+    }
+
+    fn st_uid(&self) -> u32 {
+        self.as_inner().as_inner().st_uid as u32
+    }
+
+    fn st_gid(&self) -> u32 {
+        self.as_inner().as_inner().st_gid as u32
+    }
+
+    fn st_rdev(&self) -> u64 {
+        self.as_inner().as_inner().st_rdev as u64
+    }
+
+    fn st_size(&self) -> u64 {
+        self.as_inner().as_inner().st_size as u64
+    }
+
+    fn st_atime(&self) -> i64 {
+        self.as_inner().as_inner().st_atime as i64
+    }
+
+    fn st_atime_nsec(&self) -> i64 {
+        0
+    }
+
+    fn st_mtime(&self) -> i64 {
+        self.as_inner().as_inner().st_mtime as i64
+    }
+
+    fn st_mtime_nsec(&self) -> i64 {
+        0
+    }
+
+    fn st_ctime(&self) -> i64 {
+        self.as_inner().as_inner().st_ctime as i64
+    }
+
+    fn st_ctime_nsec(&self) -> i64 {
+        0
+    }
+
+    fn st_blksize(&self) -> u64 {
+        self.as_inner().as_inner().st_blksize as u64
+    }
+
+    fn st_blocks(&self) -> u64 {
+        self.as_inner().as_inner().st_blocks as u64
+    }
+}

library/std/src/os/rtems/mod.rs

@@ -0,0 +1,4 @@
+#![stable(feature = "raw_ext", since = "1.1.0")]
+#![forbid(unsafe_op_in_unsafe_fn)]
+pub mod fs;
+pub(crate) mod raw;

library/std/src/os/rtems/raw.rs

@@ -0,0 +1,33 @@
+//! rtems raw type definitions
+
+#![stable(feature = "raw_ext", since = "1.1.0")]
+#![deprecated(
+    since = "1.8.0",
+    note = "these type aliases are no longer supported by \
+            the standard library, the `libc` crate on \
+            crates.io should be used instead for the correct \
+            definitions"
+)]
+#![allow(deprecated)]
+
+#[stable(feature = "pthread_t", since = "1.8.0")]
+pub type pthread_t = libc::pthread_t;
+
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type blkcnt_t = libc::blkcnt_t;
+
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type blksize_t = libc::blksize_t;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type dev_t = libc::dev_t;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type ino_t = libc::ino_t;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type mode_t = libc::mode_t;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type nlink_t = libc::nlink_t;
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type off_t = libc::off_t;
+
+#[stable(feature = "raw_ext", since = "1.1.0")]
+pub type time_t = libc::time_t;

library/std/src/os/unix/mod.rs

@@ -73,6 +73,8 @@ mod platform {
     pub use crate::os::openbsd::*;
     #[cfg(target_os = "redox")]
     pub use crate::os::redox::*;
+    #[cfg(target_os = "rtems")]
+    pub use crate::os::rtems::*;
     #[cfg(target_os = "solaris")]
     pub use crate::os::solaris::*;
     #[cfg(target_os = "vita")]

library/std/src/sys/pal/unix/args.rs

@@ -112,6 +112,7 @@ impl DoubleEndedIterator for Args {
     target_os = "aix",
     target_os = "nto",
     target_os = "hurd",
+    target_os = "rtems",
 ))]
 mod imp {
     use crate::ffi::c_char;

library/std/src/sys/pal/unix/env.rs

@@ -240,6 +240,17 @@ pub mod os {
     pub const EXE_EXTENSION: &str = "";
 }
 
+#[cfg(target_os = "rtems")]
+pub mod os {
+    pub const FAMILY: &str = "unix";
+    pub const OS: &str = "rtems";
+    pub const DLL_PREFIX: &str = "lib";
+    pub const DLL_SUFFIX: &str = ".so";
+    pub const DLL_EXTENSION: &str = "so";
+    pub const EXE_SUFFIX: &str = "";
+    pub const EXE_EXTENSION: &str = "";
+}
+
 #[cfg(target_os = "vxworks")]
 pub mod os {
     pub const FAMILY: &str = "unix";

library/std/src/sys/pal/unix/fs.rs

@@ -478,6 +478,7 @@ impl FileAttr {
         target_os = "horizon",
         target_os = "vita",
         target_os = "hurd",
+        target_os = "rtems",
     )))]
     pub fn modified(&self) -> io::Result<SystemTime> {
         #[cfg(target_pointer_width = "32")]
@@ -490,7 +491,12 @@ impl FileAttr {
         SystemTime::new(self.stat.st_mtime as i64, self.stat.st_mtime_nsec as i64)
     }
 
-    #[cfg(any(target_os = "vxworks", target_os = "espidf", target_os = "vita"))]
+    #[cfg(any(
+        target_os = "vxworks",
+        target_os = "espidf",
+        target_os = "vita",
+        target_os = "rtems",
+    ))]
     pub fn modified(&self) -> io::Result<SystemTime> {
         SystemTime::new(self.stat.st_mtime as i64, 0)
     }
@@ -506,6 +512,7 @@ impl FileAttr {
         target_os = "horizon",
         target_os = "vita",
         target_os = "hurd",
+        target_os = "rtems",
     )))]
     pub fn accessed(&self) -> io::Result<SystemTime> {
         #[cfg(target_pointer_width = "32")]
@@ -518,7 +525,12 @@ impl FileAttr {
         SystemTime::new(self.stat.st_atime as i64, self.stat.st_atime_nsec as i64)
     }
 
-    #[cfg(any(target_os = "vxworks", target_os = "espidf", target_os = "vita"))]
+    #[cfg(any(
+        target_os = "vxworks",
+        target_os = "espidf",
+        target_os = "vita",
+        target_os = "rtems"
+    ))]
     pub fn accessed(&self) -> io::Result<SystemTime> {
         SystemTime::new(self.stat.st_atime as i64, 0)
     }
@@ -853,6 +865,7 @@ impl Drop for Dir {
             target_os = "fuchsia",
             target_os = "horizon",
             target_os = "vxworks",
+            target_os = "rtems",
         )))]
         {
             let fd = unsafe { libc::dirfd(self.0) };
@@ -970,6 +983,7 @@ impl DirEntry {
         target_os = "aix",
         target_os = "nto",
         target_os = "hurd",
+        target_os = "rtems",
         target_vendor = "apple",
     ))]
     pub fn ino(&self) -> u64 {

library/std/src/sys/pal/unix/mod.rs

@@ -79,6 +79,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
             target_os = "l4re",
             target_os = "horizon",
             target_os = "vita",
+            target_os = "rtems",
             // The poll on Darwin doesn't set POLLNVAL for closed fds.
             target_vendor = "apple",
         )))]

library/std/src/sys/pal/unix/os.rs

@@ -31,7 +31,7 @@ cfg_if::cfg_if! {
 }
 
 extern "C" {
-    #[cfg(not(any(target_os = "dragonfly", target_os = "vxworks")))]
+    #[cfg(not(any(target_os = "dragonfly", target_os = "vxworks", target_os = "rtems")))]
     #[cfg_attr(
         any(
             target_os = "linux",
@@ -61,13 +61,14 @@ extern "C" {
 }
 
 /// Returns the platform-specific value of errno
-#[cfg(not(any(target_os = "dragonfly", target_os = "vxworks")))]
+#[cfg(not(any(target_os = "dragonfly", target_os = "vxworks", target_os = "rtems")))]
 pub fn errno() -> i32 {
     unsafe { (*errno_location()) as i32 }
 }
 
 /// Sets the platform-specific value of errno
-#[cfg(all(not(target_os = "dragonfly"), not(target_os = "vxworks")))] // needed for readdir and syscall!
+// needed for readdir and syscall!
+#[cfg(all(not(target_os = "dragonfly"), not(target_os = "vxworks"), not(target_os = "rtems")))]
 #[allow(dead_code)] // but not all target cfgs actually end up using it
 pub fn set_errno(e: i32) {
     unsafe { *errno_location() = e as c_int }
@@ -78,6 +79,16 @@ pub fn errno() -> i32 {
     unsafe { libc::errnoGet() }
 }
 
+#[cfg(target_os = "rtems")]
+pub fn errno() -> i32 {
+    extern "C" {
+        #[thread_local]
+        static _tls_errno: c_int;
+    }
+
+    unsafe { _tls_errno as i32 }
+}
+
 #[cfg(target_os = "dragonfly")]
 pub fn errno() -> i32 {
     extern "C" {
@@ -472,7 +483,7 @@ pub fn current_exe() -> io::Result<PathBuf> {
     }
 }
 
-#[cfg(target_os = "redox")]
+#[cfg(any(target_os = "redox", target_os = "rtems"))]
 pub fn current_exe() -> io::Result<PathBuf> {
     crate::fs::read_to_string("sys:exe").map(PathBuf::from)
 }

library/std/src/sys/pal/unix/process/process_unix.rs

@@ -1089,13 +1089,13 @@ fn signal_string(signal: i32) -> &'static str {
         libc::SIGURG => " (SIGURG)",
         #[cfg(not(target_os = "l4re"))]
         libc::SIGXCPU => " (SIGXCPU)",
-        #[cfg(not(target_os = "l4re"))]
+        #[cfg(not(any(target_os = "l4re", target_os = "rtems")))]
         libc::SIGXFSZ => " (SIGXFSZ)",
-        #[cfg(not(target_os = "l4re"))]
+        #[cfg(not(any(target_os = "l4re", target_os = "rtems")))]
         libc::SIGVTALRM => " (SIGVTALRM)",
         #[cfg(not(target_os = "l4re"))]
         libc::SIGPROF => " (SIGPROF)",
-        #[cfg(not(target_os = "l4re"))]
+        #[cfg(not(any(target_os = "l4re", target_os = "rtems")))]
         libc::SIGWINCH => " (SIGWINCH)",
         #[cfg(not(any(target_os = "haiku", target_os = "l4re")))]
         libc::SIGIO => " (SIGIO)",

library/std/src/sys/personality/mod.rs

@@ -31,7 +31,7 @@ cfg_if::cfg_if! {
         target_os = "psp",
         target_os = "xous",
         target_os = "solid_asp3",
-        all(target_family = "unix", not(target_os = "espidf"), not(target_os = "l4re")),
+        all(target_family = "unix", not(target_os = "espidf"), not(target_os = "l4re"), not(target_os = "rtems")),
         all(target_vendor = "fortanix", target_env = "sgx"),
     ))] {
         mod gcc;

library/unwind/Cargo.toml

@@ -34,3 +34,10 @@ llvm-libunwind = []
 # If crt-static is enabled, static link to `libunwind.a` provided by system
 # If crt-static is disabled, dynamic link to `libunwind.so` provided by system
 system-llvm-libunwind = []
+
+[lints.rust.unexpected_cfgs]
+level = "warn"
+check-cfg = [
+    # #[cfg(bootstrap)] rtems
+    'cfg(target_os, values("rtems"))',
+]

library/unwind/src/lib.rs

@@ -22,6 +22,7 @@ cfg_if::cfg_if! {
         target_os = "l4re",
         target_os = "none",
         target_os = "espidf",
+        target_os = "rtems",
     ))] {
         // These "unix" family members do not have unwinder.
     } else if #[cfg(any(

src/bootstrap/src/core/sanity.rs

@@ -34,6 +34,7 @@ pub struct Finder {
 // Targets can be removed from this list once they are present in the stage0 compiler (usually by updating the beta compiler of the bootstrap).
 const STAGE0_MISSING_TARGETS: &[&str] = &[
     // just a dummy comment so the list doesn't get onelined
+    "armv7-rtems-eabihf",
 ];
 
 /// Minimum version threshold for libstdc++ required when using prebuilt LLVM

src/doc/rustc/src/SUMMARY.md

@@ -40,6 +40,7 @@
       - [thumbv8m.base-none-eabi](./platform-support/thumbv8m.base-none-eabi.md)
       - [thumbv8m.main-none-eabi\*](./platform-support/thumbv8m.main-none-eabi.md)
     - [armv6k-nintendo-3ds](platform-support/armv6k-nintendo-3ds.md)
+    - [armv7-rtems-eabihf](platform-support/armv7-rtems-eabihf.md)
     - [armv7-sony-vita-newlibeabihf](platform-support/armv7-sony-vita-newlibeabihf.md)
     - [armv7-unknown-linux-uclibceabi](platform-support/armv7-unknown-linux-uclibceabi.md)
     - [armv7-unknown-linux-uclibceabihf](platform-support/armv7-unknown-linux-uclibceabihf.md)

src/doc/rustc/src/platform-support.md

@@ -280,6 +280,7 @@ target | std | host | notes
 `armv6-unknown-freebsd` | ✓ | ✓ | Armv6 FreeBSD
 [`armv6-unknown-netbsd-eabihf`](platform-support/netbsd.md) | ✓ | ✓ | Armv6 NetBSD w/hard-float
 [`armv6k-nintendo-3ds`](platform-support/armv6k-nintendo-3ds.md) | ? |  | Armv6k Nintendo 3DS, Horizon (Requires devkitARM toolchain)
+[`armv7-rtems-eabihf`](platform-support/armv7-rtems-eabihf.md) | ? |  | RTEMS OS for ARM BSPs
 [`armv7-sony-vita-newlibeabihf`](platform-support/armv7-sony-vita-newlibeabihf.md) | ✓ |  | Armv7-A Cortex-A9 Sony PlayStation Vita (requires VITASDK toolchain)
 [`armv7-unknown-linux-uclibceabi`](platform-support/armv7-unknown-linux-uclibceabi.md) | ✓ | ✓ | Armv7-A Linux with uClibc, softfloat
 [`armv7-unknown-linux-uclibceabihf`](platform-support/armv7-unknown-linux-uclibceabihf.md) | ✓ | ? | Armv7-A Linux with uClibc, hardfloat

src/doc/rustc/src/platform-support/armv7-rtems-eabihf.md

@@ -0,0 +1,52 @@
+# `armv7-rtems-eabihf`
+
+**Tier: 3**
+
+ARM targets for the [RTEMS realtime operating system](https://www.rtems.org)  using the RTEMS gcc cross-compiler for linking against the libraries of a specified Board Support Package (BSP).
+
+## Target maintainers
+
+- [@thesummer](https://github.com/thesummer)
+
+## Requirements
+
+The target does not support host tools. Only cross-compilation is possible.
+The cross-compiler toolchain can be obtained by following the installation instructions
+of the [RTEMS Documentation](https://docs.rtems.org/branches/master/user/index.html). Additionally to the cross-compiler also a compiled BSP
+for a board fitting the architecture needs to be available on the host.
+Currently tested has been the BSP `xilinx_zynq_a9_qemu` of RTEMS 6.
+
+`std` support is available, but not yet fully tested. Do NOT use in flight software!
+
+The target follows the EABI calling convention for `extern "C"`.
+
+The resulting binaries are in ELF format.
+
+## Building the target
+
+The target can be built by the standard compiler of Rust.
+
+## Building Rust programs
+
+Rust does not yet ship pre-compiled artifacts for this target. To compile for
+this target, you will either need to build Rust with the target enabled (see
+"Building the target" above), or build your own copy of `core` by using
+`build-std` or similar.
+
+In order to build an RTEMS executable it is also necessary to have a basic RTEMS configuration (in C) compiled to link against as this configures the operating system.
+An example can be found at this [`rtems-sys`](https://github.com/thesummer/rtems-sys) crate which could be added as an dependency to your application.
+
+## Testing
+
+The resulting binaries run fine on an emulated target (possibly also on a real Zedboard or similar).
+For example, on qemu the following command can execute the binary:
+```sh
+qemu-system-arm -no-reboot -serial null -serial mon:stdio -net none -nographic -M xilinx-zynq-a9 -m 512M -kernel <binary file>
+```
+
+While basic execution of the unit test harness seems to work. However, running the Rust testsuite on the (emulated) hardware has not yet been tested.
+
+## Cross-compilation toolchains and C code
+
+Compatible C-code can be built with the RTEMS cross-compiler toolchain `arm-rtems6-gcc`.
+For more information how to build the toolchain, RTEMS itself and RTEMS applications please have a look at the [RTEMS Documentation](https://docs.rtems.org/branches/master/user/index.html).

tests/assembly/targets/targets-elf.rs

@@ -129,6 +129,9 @@
 //@ revisions: armv7_linux_androideabi
 //@ [armv7_linux_androideabi] compile-flags: --target armv7-linux-androideabi
 //@ [armv7_linux_androideabi] needs-llvm-components: arm
+//@ revisions: armv7_rtems_eabihf
+//@ [armv7_rtems_eabihf] compile-flags: --target armv7-rtems-eabihf
+//@ [armv7_rtems_eabihf] needs-llvm-components: arm
 //@ revisions: armv7_sony_vita_newlibeabihf
 //@ [armv7_sony_vita_newlibeabihf] compile-flags: --target armv7-sony-vita-newlibeabihf
 //@ [armv7_sony_vita_newlibeabihf] needs-llvm-components: arm

tests/ui/check-cfg/well-known-values.stderr

@@ -210,7 +210,7 @@ warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
 LL |     target_os = "_UNEXPECTED_VALUE",
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: unexpected `cfg` condition value: `_UNEXPECTED_VALUE`
@@ -294,7 +294,7 @@ LL | #[cfg(target_os = "linuz")] // testing that we suggest `linux`
    |                   |
    |                   help: there is a expected value with a similar name: `"linux"`
    |
-   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `redox`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
+   = note: expected values for `target_os` are: `aix`, `android`, `cuda`, `dragonfly`, `emscripten`, `espidf`, `freebsd`, `fuchsia`, `haiku`, `hermit`, `horizon`, `hurd`, `illumos`, `ios`, `l4re`, `linux`, `macos`, `netbsd`, `none`, `nto`, `nuttx`, `openbsd`, `psp`, `redox`, `rtems`, `solaris`, `solid_asp3`, `teeos`, `trusty`, `tvos`, `uefi`, `unknown`, `visionos`, `vita`, `vxworks`, `wasi`, `watchos`, `windows`, `xous`, and `zkvm`
    = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg.html> for more information about checking conditional configuration
 
 warning: 30 warnings emitted