Merge #263p-sh-v0.5.3c-m-sh-v0.3.5

263: Import cortex-m-semihosting and panic-semihosting into this repo r=adamgreig a=jonas-schievink

Motivation:

* Allows writing QEMU tests for `cortex-m`'s functionality that use semihosting to control QEMU. Previously these crates would pull in another cortex-m version, which doesn't work. Now they have a `path` dependency on the root crate.
* Lets us share the outline-inline-assembly setup and `cargo-xtask` in general.
* Lets us share CI and bot setup between more crates.
* 2 fewer repos to triage and keep track of (I'll transfer their issues after this is merged).

I also want to import cortex-m-rt, but I'll do that in a later PR.

CI was updated to build-test all crates with all or most feature combinations, like it did before.

Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>

1 files changed, 96 insertions, 0 deletions

diff --git a/panic-semihosting/src/lib.rs b/panic-semihosting/src/lib.rs
new file mode 100644
index 0000000..1db7b72
--- /dev/null
+++ b/panic-semihosting/src/lib.rs
@@ -0,0 +1,96 @@
+//! Report panic messages to the host stderr using semihosting
+//!
+//! This crate contains an implementation of `panic_fmt` that logs panic messages to the host stderr
+//! using [`cortex-m-semihosting`]. Before logging the message the panic handler disables (masks)
+//! the device specific interrupts. After logging the message the panic handler trigger a breakpoint
+//! and then goes into an infinite loop.
+//!
+//! Currently, this crate only supports the ARM Cortex-M architecture.
+//!
+//! [`cortex-m-semihosting`]: https://crates.io/crates/cortex-m-semihosting
+//!
+//! # Usage
+//!
+//! ``` ignore
+//! #![no_std]
+//!
+//! extern crate panic_semihosting;
+//!
+//! fn main() {
+//!     panic!("FOO")
+//! }
+//! ```
+//!
+//! ``` text
+//! (gdb) monitor arm semihosting enable
+//! (gdb) continue
+//! Program received signal SIGTRAP, Trace/breakpoint trap.
+//! rust_begin_unwind (args=..., file=..., line=8, col=5)
+//!     at $CRATE/src/lib.rs:69
+//! 69          asm::bkpt();
+//! ```
+//!
+//! ``` text
+//! $ openocd -f (..)
+//! (..)
+//! panicked at 'FOO', src/main.rs:6:5
+//! ```
+//!
+//! # Optional features
+//!
+//! ## `exit`
+//!
+//! When this feature is enabled the panic handler performs an exit semihosting call after logging
+//! the panic message. This is useful when emulating the program on QEMU as it causes the QEMU
+//! process to exit with a non-zero exit code; thus it can be used to implement Cortex-M tests that
+//! run on the host.
+//!
+//! We discourage using this feature when the program will run on hardware as the exit call can
+//! leave the hardware debugger in an inconsistent state.
+//!
+//! ## `inline-asm`
+//!
+//! When this feature is enabled semihosting is implemented using inline assembly (`asm!`) and
+//! compiling this crate requires nightly.
+//!
+//! When this feature is disabled semihosting is implemented using FFI calls into an external
+//! assembly file and compiling this crate works on stable and beta.
+
+#![cfg(all(target_arch = "arm", target_os = "none"))]
+#![deny(missing_docs)]
+#![deny(warnings)]
+#![no_std]
+
+extern crate cortex_m;
+extern crate cortex_m_semihosting as sh;
+
+use core::fmt::Write;
+use core::panic::PanicInfo;
+
+#[cfg(not(feature = "exit"))]
+use cortex_m::asm;
+use cortex_m::interrupt;
+#[cfg(feature = "exit")]
+use sh::debug::{self, EXIT_FAILURE};
+use sh::hio;
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    interrupt::disable();
+
+    if let Ok(mut hstdout) = hio::hstdout() {
+        writeln!(hstdout, "{}", info).ok();
+    }
+
+    match () {
+        // Exit the QEMU process
+        #[cfg(feature = "exit")]
+        () => debug::exit(EXIT_FAILURE),
+        // OK to fire a breakpoint here because we know the microcontroller is connected to a
+        // debugger
+        #[cfg(not(feature = "exit"))]
+        () => asm::bkpt(),
+    }
+
+    loop {}
+}