Prepare for new riscv ecosystem

14 files changed, 160 insertions, 130 deletions

diff --git a/examples/hifive1/.cargo/config.toml b/examples/hifive1/.cargo/config.toml
index 2ce90b2..ab912d0 100644
--- a/examples/hifive1/.cargo/config.toml
+++ b/examples/hifive1/.cargo/config.toml
@@ -3,9 +3,9 @@ runner = "qemu-system-riscv32 -machine sifive_e,revb=true -nographic -semihostin
 # runner = "riscv64-unknown-elf-gdb -q -x gdb_init"
 rustflags = [
   "-C", "link-arg=-Thifive1-link.x",
+  "--cfg", "portable_atomic_target_feature=\"zaamo\"",
 ]
 
 [build]
 # Pick ONE of these compilation targets
-# target = "riscv32imc-unknown-none-elf"    # non-atomic support
-target = "riscv32imac-unknown-none-elf" # atomic support (partial)
+target = "riscv32imc-unknown-none-elf"
diff --git a/examples/hifive1/Cargo.lock b/examples/hifive1/Cargo.lock
index 76374dc..393e33a 100644
--- a/examples/hifive1/Cargo.lock
+++ b/examples/hifive1/Cargo.lock
@@ -16,58 +16,50 @@ checksum = "1fd0f2584146f6f2ef48085050886acf353beff7305ebd1ae69500e27c67f64b"
 
 [[package]]
 name = "critical-section"
-version = "1.1.2"
+version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7059fff8937831a9ae6f0fe4d658ffabf58f2ca96aa9dec1c889f936f705f216"
+checksum = "790eea4361631c5e7d22598ecd5723ff611904e3344ce8720784c93e3d83d40b"
 
 [[package]]
 name = "e310x"
-version = "0.11.0"
-source = "git+https://github.com/greenlsi/e310x.git?branch=master#50536cc5be2fd6adf7f879f002fdd98f66fb05f9"
+version = "0.12.0"
+source = "git+https://github.com/riscv-rust/e310x.git?branch=ehv1#ddc85fd4a8138c24d8080810469fb354ccb46d2d"
 dependencies = [
  "critical-section",
- "riscv-pac",
- "riscv-peripheral",
- "vcell",
-]
-
-[[package]]
-name = "e310x"
-version = "0.11.0"
-source = "git+https://github.com/greenlsi/e310x.git#50536cc5be2fd6adf7f879f002fdd98f66fb05f9"
-dependencies = [
- "riscv-pac",
+ "riscv",
  "riscv-peripheral",
+ "riscv-rt",
  "vcell",
 ]
 
 [[package]]
 name = "e310x-hal"
-version = "0.11.0"
-source = "git+https://github.com/greenlsi/e310x-hal.git?branch=master#931aea7ab142c1eb9eaadd4150946d8452229f27"
+version = "0.12.0"
+source = "git+https://github.com/riscv-rust/e310x.git?branch=ehv1#ddc85fd4a8138c24d8080810469fb354ccb46d2d"
 dependencies = [
- "e310x 0.11.0 (git+https://github.com/greenlsi/e310x.git?branch=master)",
- "embedded-hal 0.2.7",
- "nb 1.1.0",
+ "e310x",
+ "embedded-hal",
+ "embedded-hal-nb",
+ "nb",
  "portable-atomic",
  "riscv",
 ]
 
 [[package]]
 name = "embedded-hal"
-version = "0.2.7"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "35949884794ad573cf46071e41c9b60efb0cb311e3ca01f7af807af1debc66ff"
-dependencies = [
- "nb 0.1.3",
- "void",
-]
+checksum = "361a90feb7004eca4019fb28352a9465666b24f840f5c3cddf0ff13920590b89"
 
 [[package]]
-name = "embedded-hal"
+name = "embedded-hal-nb"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "361a90feb7004eca4019fb28352a9465666b24f840f5c3cddf0ff13920590b89"
+checksum = "fba4268c14288c828995299e59b12babdbe170f6c6d73731af1b4648142e8605"
+dependencies = [
+ "embedded-hal",
+ "nb",
+]
 
 [[package]]
 name = "equivalent"
@@ -97,17 +89,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bfb9eb618601c89945a70e254898da93b13be0388091d42117462b265bb3fad"
 dependencies = [
  "hash32",
+ "portable-atomic",
  "stable_deref_trait",
 ]
 
 [[package]]
 name = "hifive1"
-version = "0.11.0"
-source = "git+https://github.com/romancardenas/hifive1.git#ef8cea8b90bddb04509785d3e148ff145137520a"
+version = "0.14.0"
+source = "git+https://github.com/riscv-rust/e310x.git?branch=ehv1#ddc85fd4a8138c24d8080810469fb354ccb46d2d"
 dependencies = [
+ "critical-section",
  "e310x-hal",
- "embedded-hal 0.2.7",
- "nb 1.1.0",
+ "nb",
  "riscv",
 ]
 
@@ -123,47 +116,42 @@ dependencies = [
 
 [[package]]
 name = "nb"
-version = "0.1.3"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "801d31da0513b6ec5214e9bf433a77966320625a37860f910be265be6e18d06f"
-dependencies = [
- "nb 1.1.0",
-]
+checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"
 
 [[package]]
-name = "nb"
-version = "1.1.0"
+name = "paste"
+version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 
 [[package]]
 name = "portable-atomic"
-version = "1.6.0"
+version = "1.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7170ef9988bc169ba16dd36a7fa041e5c4cbeb6a35b76d4c03daded371eae7c0"
+checksum = "cc9c68a3f6da06753e9335d63e27f6b9754dd1920d941135b7ea8224f141adb2"
 
 [[package]]
-name = "proc-macro-error"
-version = "1.0.4"
+name = "proc-macro-error-attr2"
+version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+checksum = "96de42df36bb9bba5542fe9f1a054b8cc87e172759a1868aa05c1f3acc89dfc5"
 dependencies = [
- "proc-macro-error-attr",
  "proc-macro2",
  "quote",
- "syn 1.0.109",
- "version_check",
 ]
 
 [[package]]
-name = "proc-macro-error-attr"
-version = "1.0.4"
+name = "proc-macro-error2"
+version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+checksum = "11ec05c52be0a07b08061f7dd003e7d7092e0472bc731b4af7bb1ef876109802"
 dependencies = [
+ "proc-macro-error-attr2",
  "proc-macro2",
  "quote",
- "version_check",
+ "syn",
 ]
 
 [[package]]
@@ -186,57 +174,71 @@ dependencies = [
 
 [[package]]
 name = "riscv"
-version = "0.11.1"
+version = "0.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2f5c1b8bf41ea746266cdee443d1d1e9125c86ce1447e1a2615abd34330d33a9"
+checksum = "5ea8ff73d3720bdd0a97925f0bf79ad2744b6da8ff36be3840c48ac81191d7a7"
 dependencies = [
  "critical-section",
- "embedded-hal 1.0.0",
+ "embedded-hal",
+ "paste",
+ "riscv-macros",
+ "riscv-pac",
+]
+
+[[package]]
+name = "riscv-macros"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f265be5d634272320a7de94cea15c22a3bfdd4eb42eb43edc528415f066a1f25"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
 name = "riscv-pac"
-version = "0.1.1"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "18ceb4af23fdad434f938afdc35ce895a63d84f7333bb127d8065030848eb6a6"
+checksum = "8188909339ccc0c68cfb5a04648313f09621e8b87dc03095454f1a11f6c5d436"
 
 [[package]]
 name = "riscv-peripheral"
-version = "0.1.0"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "07c799fe4e144bd4dd0c68fa33a41c1485f19730eea505d195124636e1253358"
+checksum = "62858721c9afcfff0fe501db36f543c6498b64d3630446166b270625f09c3eec"
 dependencies = [
- "embedded-hal 1.0.0",
+ "embedded-hal",
  "riscv",
  "riscv-pac",
 ]
 
 [[package]]
 name = "riscv-rt"
-version = "0.12.2"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c0d35e32cf1383183e8885d8a9aa4402a087fd094dc34c2cb6df6687d0229dfe"
+checksum = "753f1bd7eb4e0003cec5e2fb60ea8e253a71d0b041bc7d1ba0fffe22e3c0294d"
 dependencies = [
  "riscv",
+ "riscv-pac",
  "riscv-rt-macros",
 ]
 
 [[package]]
 name = "riscv-rt-macros"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a8d100d466dbb76681ef6a9386f3da9abc570d57394e86da0ba5af8c4408486d"
+checksum = "30f19a85fe107b65031e0ba8ec60c34c2494069fe910d6c297f5e7cb5a6f76d0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 1.0.109",
+ "syn",
 ]
 
 [[package]]
 name = "riscv-slic"
 version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c6e12f8155a8ba8ed8dae9d68c36becb651308416592e7b45a4769d5d545385b"
+source = "git+https://github.com/romancardenas/riscv-slic.git?branch=mecall#a4800b26bfa8c1e46567703bed3154b137032023"
 dependencies = [
  "critical-section",
  "heapless",
@@ -247,12 +249,11 @@ dependencies = [
 [[package]]
 name = "riscv-slic-macros"
 version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d246759b5f1486fffb3153b5d74c964a53e88d2176dbc57c3c00aba5587a81a6"
+source = "git+https://github.com/romancardenas/riscv-slic.git?branch=mecall#a4800b26bfa8c1e46567703bed3154b137032023"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.49",
+ "syn",
 ]
 
 [[package]]
@@ -279,19 +280,19 @@ name = "rtic-macros"
 version = "2.1.0"
 dependencies = [
  "indexmap",
- "proc-macro-error",
+ "proc-macro-error2",
  "proc-macro2",
  "quote",
- "syn 2.0.49",
+ "syn",
 ]
 
 [[package]]
 name = "rtic_hifive1"
 version = "0.1.0"
 dependencies = [
- "e310x 0.11.0 (git+https://github.com/greenlsi/e310x.git)",
  "heapless",
  "hifive1",
+ "portable-atomic",
  "riscv",
  "riscv-rt",
  "rtic",
@@ -312,17 +313,6 @@ checksum = "a8f112729512f8e442d81f95a8a7ddf2b7c6b8a1a6f509a95864142b30cab2d3"
 
 [[package]]
 name = "syn"
-version = "1.0.109"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
-dependencies = [
- "proc-macro2",
- "quote",
- "unicode-ident",
-]
-
-[[package]]
-name = "syn"
 version = "2.0.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "915aea9e586f80826ee59f8453c1101f9d1c4b3964cd2460185ee8e299ada496"
@@ -343,15 +333,3 @@ name = "vcell"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "77439c1b53d2303b20d9459b1ade71a83c716e3f9c34f3228c00e6f185d6c002"
-
-[[package]]
-name = "version_check"
-version = "0.9.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
-
-[[package]]
-name = "void"
-version = "1.0.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
diff --git a/examples/hifive1/Cargo.toml b/examples/hifive1/Cargo.toml
index 42d60a7..fcd5729 100644
--- a/examples/hifive1/Cargo.toml
+++ b/examples/hifive1/Cargo.toml
@@ -10,13 +10,14 @@ edition = "2021"
 
 [dependencies]
 rtic = { path = "../../rtic" }
-heapless = "0.8.0"
-hifive1 = { git = "https://github.com/romancardenas/hifive1.git", features = ["board-redv"] }
-e310x = { git = "https://github.com/greenlsi/e310x.git", features = ["rt"]}
-riscv-rt = {version = "0.12.1", features = ["single-hart"]}
-riscv = "0.11.0"
+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"] }
+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"] }
 
 [features]
 riscv-clint-backend = ["rtic/riscv-clint-backend"]
+riscv-mecall-backend = ["rtic/riscv-mecall-backend"]
 test-critical-section = []
diff --git a/examples/hifive1/examples/prio_inheritance.rs b/examples/hifive1/examples/prio_inheritance.rs
index 5fc2399..080a13c 100644
--- a/examples/hifive1/examples/prio_inheritance.rs
+++ b/examples/hifive1/examples/prio_inheritance.rs
@@ -1,10 +1,13 @@
 #![no_main]
 #![no_std]
 
+use hifive1::hal::e310x;
 use riscv_rt as _;
 
-#[rtic::app(device = e310x, backend = HART0)]
+#[cfg_attr(feature = "riscv-mecall-backend", rtic::app(device = e310x))]
+#[cfg_attr(feature = "riscv-clint-backend", rtic::app(device = e310x, backend = H0))]
 mod app {
+    use super::e310x;
     use core::{future::Future, pin::Pin, task::Context, task::Poll};
     use hifive1::hal::prelude::*;
     use semihosting::{println, process::exit};
diff --git a/examples/hifive1/examples/static.rs b/examples/hifive1/examples/static.rs
index 34e71c6..2922dda 100644
--- a/examples/hifive1/examples/static.rs
+++ b/examples/hifive1/examples/static.rs
@@ -5,13 +5,15 @@
 #![deny(unsafe_code)]
 #![deny(missing_docs)]
 
-use hifive1 as _;
+use hifive1::hal::e310x;
 use riscv_rt as _;
 
-#[rtic::app(device = e310x, backend = HART0)]
+#[cfg_attr(feature = "riscv-mecall-backend", rtic::app(device = e310x))]
+#[cfg_attr(feature = "riscv-clint-backend", rtic::app(device = e310x, backend = H0))]
 mod app {
-    use semihosting::{process::exit, println};
+    use super::e310x;
     use heapless::spsc::{Consumer, Producer, Queue};
+    use semihosting::{println, process::exit};
 
     #[shared]
     struct Shared {}
diff --git a/examples/hifive1/examples/task.rs b/examples/hifive1/examples/task.rs
index 6968edb..2aeefe5 100644
--- a/examples/hifive1/examples/task.rs
+++ b/examples/hifive1/examples/task.rs
@@ -5,11 +5,13 @@
 #![deny(unsafe_code)]
 #![deny(missing_docs)]
 
-use hifive1 as _;
+use hifive1::hal::e310x;
 use riscv_rt as _;
 
-#[rtic::app(device = e310x, backend = HART0)]
+#[cfg_attr(feature = "riscv-mecall-backend", rtic::app(device = e310x))]
+#[cfg_attr(feature = "riscv-clint-backend", rtic::app(device = e310x, backend = H0))]
 mod app {
+    use super::e310x;
     use semihosting::{println, process::exit};
 
     #[shared]
diff --git a/examples/hifive1/examples/zero_prio_task.rs b/examples/hifive1/examples/zero_prio_task.rs
index 2528c4f..c1e1cd8 100644
--- a/examples/hifive1/examples/zero_prio_task.rs
+++ b/examples/hifive1/examples/zero_prio_task.rs
@@ -6,7 +6,7 @@
 #![deny(missing_docs)]
 
 use core::marker::PhantomData;
-use hifive1 as _;
+use hifive1::hal::e310x;
 use riscv_rt as _;
 
 /// Does not impl send
@@ -14,8 +14,10 @@ pub struct NotSend {
     _0: PhantomData<*const ()>,
 }
 
-#[rtic::app(device = e310x, backend = HART0)]
+#[cfg_attr(feature = "riscv-mecall-backend", rtic::app(device = e310x))]
+#[cfg_attr(feature = "riscv-clint-backend", rtic::app(device = e310x, backend = H0))]
 mod app {
+    use super::e310x;
     use super::NotSend;
     use core::marker::PhantomData;
     use semihosting::{println, process::exit};
diff --git a/rtic-macros/Cargo.toml b/rtic-macros/Cargo.toml
index 8611472..d4791b6 100644
--- a/rtic-macros/Cargo.toml
+++ b/rtic-macros/Cargo.toml
@@ -40,6 +40,8 @@ riscv-esp32c3 = []
 # riscv-clic = []
 # riscv-ch32 = []
 riscv-slic = []
+riscv-clint = ["riscv-slic"]
+riscv-mecall= ["riscv-slic"]
 
 # backend API test
 test-template = []
diff --git a/rtic-macros/src/codegen/bindings/riscv_slic.rs b/rtic-macros/src/codegen/bindings/riscv_slic.rs
index c9bf50a..f2dc9ed 100644
--- a/rtic-macros/src/codegen/bindings/riscv_slic.rs
+++ b/rtic-macros/src/codegen/bindings/riscv_slic.rs
@@ -13,7 +13,7 @@ use syn::{parse, Attribute, Ident};
 /// Utility function to get the SLIC interrupt module.
 pub fn interrupt_ident() -> Ident {
     let span = Span::call_site();
-    Ident::new("Interrupt", span)
+    Ident::new("SoftwareInterrupt", span)
 }
 
 pub fn interrupt_mod(_app: &App) -> TokenStream2 {
@@ -119,7 +119,7 @@ pub fn pre_init_enable_interrupts(app: &App, analysis: &CodegenAnalysis) -> Vec<
             .map(|task| (&task.args.priority, &task.args.binds)),
     ) {
         stmts.push(quote!(
-            rtic::export::set_priority(slic::Interrupt::#name, #p);
+            rtic::export::set_priority(slic::SoftwareInterrupt::#name, #p);
         ));
     }
     // Finally, we activate the interrupts
@@ -153,11 +153,11 @@ pub fn architecture_specific_analysis(app: &App, _analysis: &SyntaxAnalysis) ->
 
         return Err(parse::Error::new(first.unwrap().span(), s));
     }
-
+    #[cfg(feature = "riscv-clint")]
     if app.args.backend.is_none() {
         return Err(parse::Error::new(
             Span::call_site(),
-            "SLIC requires backend-specific configuration",
+            "CLINT requires backend-specific configuration",
         ));
     }
 
@@ -247,9 +247,19 @@ pub fn extra_modules(app: &App, _analysis: &SyntaxAnalysis) -> Vec<TokenStream2>
     stmts.push(quote!(
         use rtic::export::riscv_slic;
     ));
-    let hart_id = &app.args.backend.as_ref().unwrap().hart_id;
+    let slic = quote! {rtic::export::riscv_slic};
 
-    stmts.push(quote!(rtic::export::codegen!(pac = #device, swi = [#(#swi_slice,)*], backend = [hart_id = #hart_id]);));
+    match () {
+        #[cfg(feature = "riscv-clint")]
+        () => {
+            let hart_id = &app.args.backend.as_ref().unwrap().hart_id;
+            stmts.push(quote!(rtic::export::codegen!(slic = #slic, pac = #device, swi = [#(#swi_slice,)*], backend = [hart_id = #hart_id]);));
+        }
+        #[cfg(feature = "riscv-mecall")]
+        () => {
+            stmts.push(quote!(rtic::export::codegen!(slic = #slic, pac = #device, swi = [#(#swi_slice,)*]);));
+        }
+    }
 
     stmts
 }
diff --git a/rtic-macros/src/syntax/backend/riscv_slic.rs b/rtic-macros/src/syntax/backend/riscv_slic.rs
index 2ed8e77..b579b01 100644
--- a/rtic-macros/src/syntax/backend/riscv_slic.rs
+++ b/rtic-macros/src/syntax/backend/riscv_slic.rs
@@ -1,16 +1,27 @@
 use syn::{
     parse::{Parse, ParseStream},
-    Ident, Result,
+    Result,
 };
 
 #[derive(Debug)]
 pub struct BackendArgs {
-    pub hart_id: Ident,
+    #[cfg(feature = "riscv-clint")]
+    pub hart_id: syn::Ident,
 }
 
 impl Parse for BackendArgs {
     fn parse(input: ParseStream) -> Result<Self> {
-        let hart_id = input.parse()?;
-        Ok(BackendArgs { hart_id })
+        match () {
+            #[cfg(feature = "riscv-clint")]
+            () => {
+                let hart_id = input.parse()?;
+                Ok(BackendArgs { hart_id })
+            }
+            #[cfg(feature = "riscv-mecall")]
+            () => Err(syn::Error::new(
+                input.span(),
+                "riscv-mecall backend does not accept any arguments",
+            )),
+        }
     }
 }
diff --git a/rtic/Cargo.toml b/rtic/Cargo.toml
index 80a40a8..ee6b0e3 100644
--- a/rtic/Cargo.toml
+++ b/rtic/Cargo.toml
@@ -25,7 +25,7 @@ features = ["thumbv7-backend"]
 name = "rtic"
 
 [dependencies]
-riscv-slic = { version = "0.1.1", optional = true }
+riscv-slic = { version = "0.2.0", optional = true }
 esp32c3 = { version = "0.27.0", optional = true }
 riscv = { version = "0.12.1", optional = true }
 cortex-m = { version = "0.7.0", optional = true }
@@ -63,7 +63,12 @@ riscv-esp32c3-backend = ["esp32c3", "riscv", "rtic-macros/riscv-esp32c3"]
 riscv-clint-backend = [
   "riscv",
   "riscv-slic/clint-backend",
-  "rtic-macros/riscv-slic",
+  "rtic-macros/riscv-clint",
+]
+riscv-mecall-backend = [
+  "riscv",
+  "riscv-slic/mecall-backend",
+  "rtic-macros/riscv-mecall",
 ]
 
 # needed for testing
diff --git a/rtic/build.rs b/rtic/build.rs
index 8c87b56..a1fed29 100644
--- a/rtic/build.rs
+++ b/rtic/build.rs
@@ -27,7 +27,7 @@ fn main() {
         "riscv-esp32c3-backend" => {
             println!("cargo:rustc-cfg=feature=\"riscv-esp32c3\"");
         }
-        "riscv-clint-backend" => {
+        "riscv-clint-backend" | "riscv-mecall-backend" => {
             println!("cargo:rustc-cfg=feature=\"riscv-slic\"");
         }
         _ => {
diff --git a/rtic/src/export/slic.rs b/rtic/src/export/slic.rs
index f0c17a3..626fdcb 100644
--- a/rtic/src/export/slic.rs
+++ b/rtic/src/export/slic.rs
@@ -1,7 +1,10 @@
 pub use riscv_slic::{lock, pend, run, InterruptNumber};
 
-#[cfg(all(feature = "riscv-slic", not(feature = "riscv-clint-backend")))]
-compile_error!("Building for the riscv-slic, but 'riscv-clint-backend' not selected");
+#[cfg(all(
+    feature = "riscv-slic",
+    not(any(feature = "riscv-clint-backend", feature = "riscv-mecall-backend"))
+))]
+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};
diff --git a/xtask/src/argument_parsing.rs b/xtask/src/argument_parsing.rs
index 8707ec5..f50e285 100644
--- a/xtask/src/argument_parsing.rs
+++ b/xtask/src/argument_parsing.rs
@@ -167,8 +167,10 @@ pub enum Backends {
     Thumbv8Base,
     Thumbv8Main,
     RiscvEsp32C3,
-    Riscv32ImcClint, // not working yet (issues with portable-atomic features...)
+    Riscv32ImcClint,
+    Riscv32ImcMecall,
     Riscv32ImacClint,
+    Riscv32ImacMecall,
 }
 
 impl Backends {
@@ -179,8 +181,10 @@ impl Backends {
             Backends::Thumbv7 => ARMV7M,
             Backends::Thumbv8Base => ARMV8MBASE,
             Backends::Thumbv8Main => ARMV8MMAIN,
-            Backends::Riscv32ImcClint | Backends::RiscvEsp32C3 => RISCV32IMC,
-            Backends::Riscv32ImacClint => RISCV32IMAC,
+            Backends::Riscv32ImcClint | Backends::Riscv32ImcMecall | Backends::RiscvEsp32C3 => {
+                RISCV32IMC
+            }
+            Backends::Riscv32ImacClint | Backends::Riscv32ImacMecall => RISCV32IMAC,
         }
     }
 
@@ -193,6 +197,7 @@ impl Backends {
             Backends::Thumbv8Main => "thumbv8main-backend",
             Backends::RiscvEsp32C3 => "riscv-esp32c3-backend",
             Backends::Riscv32ImcClint | Backends::Riscv32ImacClint => "riscv-clint-backend",
+            Backends::Riscv32ImcMecall | Backends::Riscv32ImacMecall => "riscv-mecall-backend",
         }
     }
     #[allow(clippy::wrong_self_convention)]
@@ -202,6 +207,7 @@ impl Backends {
             Backends::Thumbv7 | Backends::Thumbv8Main => "cortex-m-basepri",
             Backends::RiscvEsp32C3 => "riscv-esp32c3",
             Backends::Riscv32ImcClint | Backends::Riscv32ImacClint => "riscv-clint",
+            Backends::Riscv32ImcMecall | Backends::Riscv32ImacMecall => "riscv-mecall",
         }
     }
 }
@@ -246,7 +252,12 @@ impl Platforms {
         let c = "-C".to_string();
         match self {
             Platforms::Esp32C3 => vec![c, "link-arg=-Tlinkall.x".to_string()],
-            Platforms::Hifive1 => vec![c, "link-arg=-Thifive1-link.x".to_string()],
+            Platforms::Hifive1 => vec![
+                c.clone(),
+                "link-arg=-Thifive1-link.x".to_string(),
+                c,
+                "portable_atomic_target_feature=\"zaamo\"".to_string(),
+            ],
             Platforms::Lm3s6965 => vec![c, "link-arg=-Tlink.x".to_string()],
             Platforms::Nrf52840 => vec![
                 c.clone(),