Add mecall backend

Author: romancardenas

examples/hifive1/Cargo.lock

@@ -11,11 +11,11 @@ edition = "2021"
 [dependencies]
 rtic = { path = "../../rtic" }
 heapless = { version = "0.8.0", features = ["portable-atomic-unsafe-assume-single-core"] }
-hifive1 = { git = "https://github.com/riscv-rust/e310x.git", branch = "ehv1", features = ["board-redv"] }
+hifive1 = { version = "0.13.0", features = ["board-redv"] }
 riscv-rt = {version = "0.13.0", features = ["single-hart"]}
 riscv = "0.12.1"
 semihosting = { version = "0.1", features = ["stdio", "panic-handler"] }
-portable-atomic = { version = "1.9", features = ["unsafe-assume-single-core", "force-amo"] }
+portable-atomic = { version = "1", features = ["unsafe-assume-single-core", "force-amo"] }
 
 [features]
 riscv-clint-backend = ["rtic/riscv-clint-backend"]

examples/hifive1/Cargo.toml

@@ -108,10 +108,6 @@ pub fn pre_init_checks(app: &App, _analysis: &SyntaxAnalysis) -> Vec<TokenStream
 pub fn pre_init_enable_interrupts(app: &App, analysis: &CodegenAnalysis) -> Vec<TokenStream2> {
     let mut stmts = vec![];
 
-    // First, we reset and disable all the interrupt controllers
-    stmts.push(quote!(rtic::export::clear_interrupts();));
-
-    // Then, we set the corresponding priorities
     let interrupt_ids = analysis.interrupts.iter().map(|(p, (id, _))| (p, id));
     for (&p, name) in interrupt_ids.chain(
         app.hardware_tasks
@@ -122,8 +118,7 @@ pub fn pre_init_enable_interrupts(app: &App, analysis: &CodegenAnalysis) -> Vec<
             rtic::export::set_priority(slic::SoftwareInterrupt::#name, #p);
         ));
     }
-    // Finally, we activate the interrupts
-    stmts.push(quote!(rtic::export::set_interrupts();));
+
     stmts
 }
 

rtic-macros/src/codegen/bindings/riscv_slic.rs

@@ -23,6 +23,9 @@ Example:
 ### Changed
 
 - Updated esp32c3 dependency to v0.27.0
+### Added
+
+- Support for RISC-V targets compatible with `riscv-slic` using machine-level environment call exceptions.
 
 ## [v2.1.2] - 2024-12-06
 

rtic/CHANGELOG.md

@@ -7,16 +7,16 @@ pub use riscv_slic::{lock, pend, run, InterruptNumber};
 compile_error!("Building for the riscv-slic, but no compatible backend selected");
 
 /// USE CASE RE-EXPORTS: needed for SLIC-only
-pub use riscv_slic::{self, clear_interrupts, codegen, set_interrupts, set_priority};
+pub use riscv_slic::{self, codegen, set_priority};
 
 pub mod interrupt {
+    #[inline]
     pub fn disable() {
         riscv_slic::disable();
-        riscv_slic::clear_interrupts();
     }
 
+    #[inline]
     pub unsafe fn enable() {
-        riscv_slic::set_interrupts();
         riscv_slic::enable();
     }
 }