diff --git a/src/doc/rustc/src/platform-support/amdgcn-amd-amdhsa.md b/src/doc/rustc/src/platform-support/amdgcn-amd-amdhsa.md index 16152dd2dad51..dbdb96283a5fa 100644 --- a/src/doc/rustc/src/platform-support/amdgcn-amd-amdhsa.md +++ b/src/doc/rustc/src/platform-support/amdgcn-amd-amdhsa.md @@ -20,8 +20,8 @@ The format of binaries is a linked ELF. Binaries must be built with no-std. They can use `core` and `alloc` (`alloc` only if an allocator is supplied). -At least one function needs to use the `"gpu-kernel"` calling convention and should be marked with `no_mangle` for simplicity. -Functions using the `"gpu-kernel"` calling convention are kernel entrypoints and can be used from the host runtime. +At least one function should use the `"gpu-kernel"` calling convention and should be marked with `no_mangle` or `export_name`. +Functions using the `"gpu-kernel"` calling convention are kernel entrypoints and can be launched from the host runtime. ## Building the target @@ -34,6 +34,9 @@ The generations are exposed as different target-cpus in the backend. As there are many, Rust does not ship pre-compiled libraries for this target. Therefore, you have to build your own copy of `core` by using `cargo -Zbuild-std=core` or similar. +An allocator and `println!()` support is provided by the [`amdgpu-device-libs`] crate. +Both features rely on the [HIP] runtime. + To build a binary, create a no-std library: ```rust,ignore (platform-specific) // src/lib.rs @@ -65,6 +68,8 @@ lto = true The target-cpu must be from the list [supported by LLVM] (or printed with `rustc --target amdgcn-amd-amdhsa --print target-cpus`). The GPU version on the current system can be found e.g. with [`rocminfo`]. +For a GPU series that has xnack support but the target GPU has not, the `-xnack-support` target-feature needs to be enabled. +I.e. if the ISA info as printed with [`rocminfo`] says something about `xnack-`, e.g. `gfx1010:xnack-`, add `-Ctarget-feature=-xnack-support` to the rustflags. Example `.cargo/config.toml` file to set the target and GPU generation: ```toml @@ -72,6 +77,7 @@ Example `.cargo/config.toml` file to set the target and GPU generation: [build] target = "amdgcn-amd-amdhsa" rustflags = ["-Ctarget-cpu=gfx1100"] +# Add "-Ctarget-feature=-xnack-support" for xnack- GPUs (see above) [unstable] build-std = ["core"] # Optional: "alloc" @@ -85,8 +91,6 @@ Example code on how to load a compiled binary and run it is available in [ROCm e On Linux, binaries can also run through the HSA runtime as implemented in [ROCR-Runtime]. - -