diff options
| -rw-r--r-- | cortex-m-rt/.gitignore | 3 | ||||
| -rw-r--r-- | cortex-m-rt/Cargo.toml | 24 | ||||
| -rw-r--r-- | cortex-m-rt/LICENSE-APACHE | 201 | ||||
| -rw-r--r-- | cortex-m-rt/LICENSE-MIT | 25 | ||||
| -rw-r--r-- | cortex-m-rt/README.md | 20 | ||||
| -rw-r--r-- | cortex-m-rt/build.rs | 29 | ||||
| -rw-r--r-- | cortex-m-rt/link.x | 54 | ||||
| -rw-r--r-- | cortex-m-rt/src/lang_items.rs | 63 | ||||
| -rw-r--r-- | cortex-m-rt/src/lib.rs | 81 |
9 files changed, 500 insertions, 0 deletions
diff --git a/cortex-m-rt/.gitignore b/cortex-m-rt/.gitignore new file mode 100644 index 0000000..6dc3db1 --- /dev/null +++ b/cortex-m-rt/.gitignore @@ -0,0 +1,3 @@ +**/*.rs.bk +Cargo.lock +target/ diff --git a/cortex-m-rt/Cargo.toml b/cortex-m-rt/Cargo.toml new file mode 100644 index 0000000..2f1ce0d --- /dev/null +++ b/cortex-m-rt/Cargo.toml @@ -0,0 +1,24 @@ +[package] +name = "cortex-m-rt" +version = "0.1.0" +authors = ["Jorge Aparicio <japaricious@gmail.com>"] + +[dependencies] +r0 = "0.2.0" + +[dependencies.cortex-m] +optional = true +version = "0.2.0" + +[dependencies.cortex-m-semihosting] +optional = true +version = "0.1.3" + +[dependencies.compiler_builtins] +features = ["mem"] +git = "https://github.com/rust-lang-nursery/compiler-builtins" + +[features] +linker-script = [] +panic-over-itm = ["cortex-m"] +panic-over-semihosting = ["cortex-m-semihosting"]
\ No newline at end of file diff --git a/cortex-m-rt/LICENSE-APACHE b/cortex-m-rt/LICENSE-APACHE new file mode 100644 index 0000000..16fe87b --- /dev/null +++ b/cortex-m-rt/LICENSE-APACHE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. Definitions. + + "License" shall mean the terms and conditions for use, reproduction, + and distribution as defined by Sections 1 through 9 of this document. + + "Licensor" shall mean the copyright owner or entity authorized by + the copyright owner that is granting the License. + + "Legal Entity" shall mean the union of the acting entity and all + other entities that control, are controlled by, or are under common + control with that entity. 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IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/cortex-m-rt/README.md b/cortex-m-rt/README.md new file mode 100644 index 0000000..81d2d6f --- /dev/null +++ b/cortex-m-rt/README.md @@ -0,0 +1,20 @@ +# `cortex-m-rt` + +> Minimal startup / runtime for Cortex-M microcontrollers + +# License + +Licensed under either of + +- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or + http://www.apache.org/licenses/LICENSE-2.0) + +- MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) + +at your option. + +## Contribution + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in the work by you, as defined in the Apache-2.0 license, shall be +dual licensed as above, without any additional terms or conditions. diff --git a/cortex-m-rt/build.rs b/cortex-m-rt/build.rs new file mode 100644 index 0000000..c52b434 --- /dev/null +++ b/cortex-m-rt/build.rs @@ -0,0 +1,29 @@ +#[cfg(feature = "linker-script")] +mod imp { + use std::env; + use std::fs::File; + use std::io::Write; + use std::path::PathBuf; + + pub fn main() { + // Put the linker script somewhere the linker can find it + let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap()); + File::create(out.join("link.x")) + .unwrap() + .write_all(include_bytes!("link.x")) + .unwrap(); + println!("cargo:rustc-link-search={}", out.display()); + + println!("cargo:rerun-if-changed=build.rs"); + println!("cargo:rerun-if-changed=link.x"); + } +} + +#[cfg(not(feature = "linker-script"))] +mod imp { + pub fn main() {} +} + +fn main() { + imp::main(); +} diff --git a/cortex-m-rt/link.x b/cortex-m-rt/link.x new file mode 100644 index 0000000..f1159c9 --- /dev/null +++ b/cortex-m-rt/link.x @@ -0,0 +1,54 @@ +INCLUDE memory.x + +SECTIONS +{ + .text ORIGIN(FLASH) : + { + /* Vector table */ + _VECTOR_TABLE = .; + LONG(ORIGIN(RAM) + LENGTH(RAM)); + LONG(__reset + 1); + + KEEP(*(.rodata._EXCEPTIONS)); + __exceptions = .; + + KEEP(*(.rodata._INTERRUPTS)); + __interrupts = .; + + /* Entry point: the reset handler */ + __reset = .; + *(.text.start); + + *(.text.*); + *(.rodata.*); + } > FLASH + + .bss : ALIGN(4) + { + _sbss = .; + *(.bss.*); + _ebss = ALIGN(4); + } > RAM + + .data : ALIGN(4) + { + _sdata = .; + *(.data.*); + _edata = ALIGN(4); + } > RAM AT > FLASH + + _sidata = LOADADDR(.data); + + /DISCARD/ : + { + /* Unused unwinding stuff */ + *(.ARM.exidx.*) + *(.ARM.extab.*) + } +} + +ASSERT(__exceptions - ORIGIN(FLASH) == 0x40, + "you must define the _EXCEPTIONS symbol"); + +ASSERT(__interrupts - __exceptions > 0, + "you must define the _INTERRUPTS symbol"); diff --git a/cortex-m-rt/src/lang_items.rs b/cortex-m-rt/src/lang_items.rs new file mode 100644 index 0000000..bd7c4db --- /dev/null +++ b/cortex-m-rt/src/lang_items.rs @@ -0,0 +1,63 @@ +/// Default panic handler +#[lang = "panic_fmt"] +#[linkage = "weak"] +unsafe extern "C" fn panic_fmt( + _args: ::core::fmt::Arguments, + _file: &'static str, + _line: u32, +) -> ! { + match () { + #[cfg(feature = "panic-over-itm")] + () => { + use cortex_m::itm; + use cortex_m::peripheral::ITM; + + let port = &(*ITM.get()).stim[0]; + iprint!(port, "panicked at '"); + itm::write_fmt(port, _args); + iprintln!(port, "', {}:{}", _file, _line); + } + #[cfg(feature = "panic-over-semihosting")] + () => { + hprint!("panicked at '"); + ::cortex_m_semihosting::io::write_fmt(_args); + hprintln!("', {}:{}", _file, _line); + } + #[cfg(not(any(feature = "panic-over-itm", + feature = "panic-over-semihosting")))] + () => {} + } + + asm!("bkpt" :::: "volatile"); + + loop {} +} + +/// Lang item required to make the normal `main` work in applications +// This is how the `start` lang item works: +// When `rustc` compiles a binary crate, it creates a `main` function that looks +// like this: +// +// ``` +// #[export_name = "main"] +// pub extern "C" fn rustc_main(argc: isize, argv: *const *const u8) -> isize { +// start(main) +// } +// ``` +// +// Where `start` is this function and `main` is the binary crate's `main` +// function. +// +// The final piece is that the entry point of our program, the reset handler, +// has to call `rustc_main`. That's covered by the `reset_handler` function in +// root of this crate. +#[lang = "start"] +extern "C" fn start( + main: fn(), + _argc: isize, + _argv: *const *const u8, +) -> isize { + main(); + + 0 +} diff --git a/cortex-m-rt/src/lib.rs b/cortex-m-rt/src/lib.rs new file mode 100644 index 0000000..e1ec26f --- /dev/null +++ b/cortex-m-rt/src/lib.rs @@ -0,0 +1,81 @@ +//! Minimal startup / runtime for Cortex-M microcontrollers +//! +//! Provides +//! +//! - Before main initialization of the `.bss` and `.data` sections +//! +//! - An overridable (\*) `panic_fmt` implementation that prints overs the ITM +//! or through semihosting depending on the enabled Cargo feature. +//! +//! - Minimal `start` lang item, to support vanilla `fn main()`. NOTE the +//! processor goes into "reactive" mode (`loop { asm!("wfi") }`) after +//! returning from `main`. +//! +//! (\*) To override the `panic_fmt` implementation, simply create a new +//! `rust_begin_unwind` symbol: +//! +//! ``` +//! #[no_mangle] +//! pub unsafe extern "C" fn rust_begin_unwind( +//! _args: ::core::fmt::Arguments, +//! _file: &'static str, +//! _line: u32, +//! ) -> ! { +//! .. +//! } +//! ``` + +#![deny(missing_docs)] +#![deny(warnings)] +#![feature(asm)] +#![feature(compiler_builtins_lib)] +#![feature(lang_items)] +#![feature(linkage)] +#![no_std] + +#[cfg(feature = "panic-over-itm")] +#[macro_use] +extern crate cortex_m; +extern crate compiler_builtins; +#[cfg(feature = "panic-over-semihosting")] +#[macro_use] +extern crate cortex_m_semihosting; +extern crate r0; + +mod lang_items; + +// TODO make private and use `#[used]` +/// The reset handler +/// +/// This is the entry point of all programs +#[doc(hidden)] +#[export_name = "start"] +pub unsafe extern "C" fn reset_handler() -> ! { + extern "C" { + static mut _ebss: u32; + static mut _sbss: u32; + + static mut _edata: u32; + static mut _sdata: u32; + + static _sidata: u32; + } + + ::r0::zero_bss(&mut _sbss, &mut _ebss); + ::r0::init_data(&mut _sdata, &mut _edata, &_sidata); + + // NOTE `rustc` forces this signature on us. See `src/lang_items.rs` + extern "C" { + fn main(argc: isize, argv: *const *const u8) -> isize; + } + + // Neither `argc` or `argv` make sense in bare metal contexts so we just + // stub them + main(0, ::core::ptr::null()); + + // If `main` returns, then we go into "reactive" mode and attend interrupts + // as they occur. + loop { + asm!("wfi" :::: "volatile"); + } +} |