diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md index fe090a73327..83f554b507a 100644 --- a/src/doc/rustc/src/platform-support.md +++ b/src/doc/rustc/src/platform-support.md @@ -223,6 +223,7 @@ target | std | host | notes `aarch64_be-unknown-linux-gnu_ilp32` | ✓ | ✓ | ARM64 Linux (big-endian, ILP32 ABI) `aarch64_be-unknown-linux-gnu` | ✓ | ✓ | ARM64 Linux (big-endian) [`arm64_32-apple-watchos`](platform-support/apple-watchos.md) | ✓ | | ARM Apple WatchOS 64-bit with 32-bit pointers +[`armeb-linux-gnueabi`](platform-support/armeb-linux-gnueabi.md) | ✓ | ? | ARM BE8 the default ARM big-endian architecture since [ARMv6](https://developer.arm.com/documentation/101754/0616/armlink-Reference/armlink-Command-line-Options/--be8?lang=en). `armv4t-none-eabi` | * | | ARMv4T A32 `armv4t-unknown-linux-gnueabi` | ? | | `armv5te-unknown-linux-uclibceabi` | ? | | ARMv5TE Linux with uClibc diff --git a/src/doc/rustc/src/platform-support/armeb-linux-gnueabi.md b/src/doc/rustc/src/platform-support/armeb-linux-gnueabi.md new file mode 100644 index 00000000000..e9576fad953 --- /dev/null +++ b/src/doc/rustc/src/platform-support/armeb-linux-gnueabi.md @@ -0,0 +1,74 @@ +# armeb-linux-gnueabi +**Tier: 3** + +Target for cross-compiling Linux user-mode applications targetting the ARM BE8 architecture. + +## Overview +BE8 architecture retains the same little-endian ordered code-stream used by conventional little endian ARM systems, however the data accesses are in big-endian. BE8 is used primarily in high-performance networking applications where the ability to read packets in their native "Network Byte Order" is important (many network protocols transmit data in big-endian byte order for their wire formats). + +## History +BE8 architecture is the default big-endian architecture for ARM since [ARMv6](https://developer.arm.com/documentation/101754/0616/armlink-Reference/armlink-Command-line-Options/--be8?lang=en). It's predecessor, used for ARMv4 and ARMv5 devices was [BE32](https://developer.arm.com/documentation/dui0474/j/linker-command-line-options/--be32). On ARMv6 architecture, endianness can be configured via [system registers](https://developer.arm.com/documentation/ddi0290/g/unaligned-and-mixed-endian-data-access-support/mixed-endian-access-support/interaction-between-the-bus-protocol-and-the-core-endianness). However, BE32 was withdrawn for [ARMv7](https://developer.arm.com/documentation/ddi0406/cb/Appendixes/Deprecated-and-Obsolete-Features/Obsolete-features/Support-for-BE-32-endianness-model) onwards. + +## Target Maintainers +* [@WorksButNotTested](https://github.com/WorksButNotTested) + +## Requirements +The target is cross-compiled. This target supports `std` in the normal way (indeed only nominal changes are required from the standard ARM configuration). + +## Target definition +The target definition can be seen [here](../../../../../compiler/rustc_target/src/spec/armeb_linux_gnueabi.rs). In particular, it should be noted that the `features` specify that this target is built for the ARMv8 core. Though this can likely be modified as required. + +## Building the target +Because it is Tier 3, rust does not yet ship pre-compiled artifacts for this target. + +Therefore, you can build Rust with support for the target by adding it to the target list in config.toml, a sample configuration is shown below. It is expected that the user already have a working GNU compiler toolchain and update the paths accordingly. + +```toml +[llvm] +download-ci-llvm = false +skip-rebuild = true +optimize = true +ninja = true +targets = "ARM;X86" +clang = false + +[build] +target = ["x86_64-unknown-linux-gnu", "armeb-linux-gnueabi"] +docs = false +docs-minification = false +compiler-docs = false +[install] +prefix = "/home/user/x-tools/rust/" + +[rust] +debug-logging=true +backtrace = true +incremental = true + +[target.x86_64-unknown-linux-gnu] + +[dist] + +[target.armeb-linux-gnueabi] +cc = "/home/user/x-tools/armeb-linux-gnueabi/bin/armeb-linux-gnueabi-gcc" +cxx = "/home/user/x-tools/armeb-linux-gnueabi/bin/armeb-linux-gnueabi-g++" +ar = "/home/user/x-tools/armeb-linux-gnueabi/bin/armeb-linux-gnueabi-ar" +ranlib = "/home/user/x-tools/armeb-linux-gnueabi/bin/armeb-linux-gnueabi-ranlib" +linker = "/home/user/x-tools/armeb-linux-gnueabi/bin/armeb-linux-gnueabi-gcc" +llvm-config = "/home/user/x-tools/clang/bin/llvm-config" +llvm-filecheck = "/home/user/x-tools/clang/bin/FileCheck" +``` + +## Building Rust programs + +The following `.cargo/config` is needed inside any project directory to build for the BE8 target: + +```toml +[build] +target = "armeb-linux-gnueabi" + +[target.armeb-linux-gnueabi] +linker = "armeb-linux-gnueabi-gcc" +``` + +Note that it is expected that the user has a suitable linker from the GNU toolchain.