Merge pull request #290 from rmsyn/riscv/register/mconfigptr

register: add `mconfigptr` register

Author: romancardenas

.github/workflows/riscv-rt.yaml

@@ -10,8 +10,8 @@ jobs:
   build-riscv:
     strategy:
       matrix:
-        # All generated code should be running on stable now, MRSV is 1.61.0
-        toolchain: [ stable, nightly, 1.61.0 ]
+        # All generated code should be running on stable now, MRSV is 1.67.0
+        toolchain: [ stable, nightly, 1.67.0 ]
         target:
           - riscv32i-unknown-none-elf
           - riscv32im-unknown-none-elf
@@ -28,9 +28,9 @@ jobs:
           - toolchain: nightly
             experimental: true
         exclude:
-          - toolchain: 1.61.0
+          - toolchain: 1.67.0
             target: riscv32im-unknown-none-elf
-          - toolchain: 1.61.0
+          - toolchain: 1.67.0
             target: riscv32imafc-unknown-none-elf
     runs-on: ubuntu-latest
     continue-on-error: ${{ matrix.experimental || false }}

.github/workflows/riscv-semihosting.yaml

@@ -11,8 +11,8 @@ jobs:
   build-riscv:
     strategy:
       matrix:
-        # All generated code should be running on stable now, MRSV is 1.61.0
-        toolchain: [ stable, nightly, 1.61.0 ]
+        # All generated code should be running on stable now, MRSV is 1.67.0
+        toolchain: [ stable, nightly, 1.67.0 ]
         target:
           - riscv32i-unknown-none-elf
           - riscv32imc-unknown-none-elf

.github/workflows/riscv-target-parser.yaml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       matrix:
         os: [ macos-latest, ubuntu-latest, windows-latest ]
-        toolchain: [ stable, nightly, 1.61.0 ]
+        toolchain: [ stable, nightly, 1.67.0 ]
         include:
           # Nightly is only for reference and allowed to fail
           - rust: nightly

.github/workflows/riscv.yaml

@@ -11,8 +11,8 @@ jobs:
   build-riscv:
     strategy:
       matrix:
-        # All generated code should be running on stable now, MRSV is 1.61.0
-        toolchain: [ stable, nightly, 1.61.0 ]
+        # All generated code should be running on stable now, MRSV is 1.67.0
+        toolchain: [ stable, nightly, 1.67.0 ]
         target:
           - riscv32i-unknown-none-elf
           - riscv32imc-unknown-none-elf

.github/workflows/tests.yaml

@@ -20,8 +20,8 @@ jobs:
   run-build:
     strategy:
       matrix:
-        # All generated code should be running on stable now, MRSV is 1.61.0
-        toolchain: [ stable, nightly, 1.61.0 ]
+        # All generated code should be running on stable now, MRSV is 1.67.0
+        toolchain: [ stable, nightly, 1.67.0 ]
         target:
           - riscv32i-unknown-none-elf
           - riscv32im-unknown-none-elf
@@ -37,9 +37,9 @@ jobs:
           - toolchain: nightly
             experimental: true
         exclude:
-          - toolchain: 1.61.0
+          - toolchain: 1.67.0
             target: riscv32im-unknown-none-elf
-          - toolchain: 1.61.0
+          - toolchain: 1.67.0
             target: riscv32imafc-unknown-none-elf
     runs-on: ubuntu-latest
     continue-on-error: ${{ matrix.experimental || false }}

riscv/CHANGELOG.md

@@ -13,7 +13,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Write utilities for `mcycle`, `minstret`
 - Add `senvcfg` CSR
 - Add `scontext` CSR
-- Add `mtinst` CSR
+- Add `mconfigptr` CSR
+- Bump MSRV to 1.67.0 for `log` to `ilog` name change
 
 ### Changed
 

riscv/Cargo.toml

@@ -2,7 +2,7 @@
 name = "riscv"
 version = "0.13.0"
 edition = "2021"
-rust-version = "1.61"
+rust-version = "1.67"
 repository = "https://github.com/rust-embedded/riscv"
 authors = ["The RISC-V Team <risc-v@teams.rust-embedded.org>"]
 categories = ["embedded", "hardware-support", "no-std"]

riscv/src/register.rs

@@ -110,6 +110,9 @@ pub mod minstreth;
 mod mhpmeventx;
 pub use self::mhpmeventx::*;
 
+// Machine configuration
+pub mod mconfigptr;
+
 #[cfg(test)]
 mod tests;
 

riscv/src/register/mconfigptr.rs

@@ -0,0 +1,107 @@
+//! `mconfigptr` register.
+
+use crate::result::{Error, Result};
+
+const MASK: usize = usize::MAX;
+
+read_only_csr! {
+    /// `mconfigptr` register.
+    Mconfigptr: 0xf15,
+    mask: MASK,
+    sentinel: 0,
+}
+
+impl Mconfigptr {
+    /// Represents the bitshift for a properly aligned configuration pointer.
+    pub const ALIGN_SHIFT: usize = (usize::BITS / 8).ilog2() as usize;
+    /// Represents the bitmask for a properly aligned configuration pointer.
+    pub const ALIGN_MASK: usize = (1usize << Self::ALIGN_SHIFT) - 1;
+
+    /// Gets the pointer to the machine configuration structure.
+    ///
+    /// # Panics
+    ///
+    /// Panics if:
+    ///
+    /// - the value is `0`, indicating no configuration structure
+    /// - the pointer is not aligned to an MXLEN byte value
+    pub fn as_ptr(&self) -> *const u8 {
+        self.try_as_ptr().unwrap()
+    }
+
+    /// Attempts to get the pointer to the machine configuration structure.
+    ///
+    /// # Note
+    ///
+    /// Returns an error if:
+    ///
+    /// - the value is `0`, indicating no configuration structure
+    /// - the pointer is not aligned to an MXLEN byte value
+    pub const fn try_as_ptr(&self) -> Result<*const u8> {
+        match self.bits() {
+            0 => Err(Error::InvalidFieldVariant {
+                field: "mconfigptr",
+                value: 0,
+            }),
+            p if p & Self::ALIGN_MASK != 0 => Err(Error::InvalidFieldValue {
+                field: "mconfigptr",
+                value: p,
+                bitmask: !Self::ALIGN_MASK,
+            }),
+            p => Ok(p as *const _),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_mconfigptr() {
+        #[cfg(target_arch = "riscv32")]
+        const EXP_SHIFT: usize = 2;
+        #[cfg(not(target_arch = "riscv32"))]
+        const EXP_SHIFT: usize = 3;
+
+        const EXP_MASK: usize = (1usize << EXP_SHIFT) - 1;
+
+        assert_eq!(Mconfigptr::ALIGN_SHIFT, EXP_SHIFT);
+        assert_eq!(Mconfigptr::ALIGN_MASK, EXP_MASK);
+
+        (1..usize::BITS)
+            .map(|b| ((1u128 << b) - 1) as usize)
+            .for_each(|ptr| {
+                let mconfigptr = Mconfigptr::from_bits(ptr);
+                assert_eq!(mconfigptr.bits(), ptr);
+
+                match mconfigptr.try_as_ptr() {
+                    Ok(cfg_ptr) => {
+                        assert_eq!(cfg_ptr, ptr as *const _);
+                        assert_eq!(mconfigptr.as_ptr(), ptr as *const _);
+                    }
+                    Err(err) if ptr == 0 => assert_eq!(
+                        err,
+                        Error::InvalidFieldVariant {
+                            field: "mconfigptr",
+                            value: 0
+                        }
+                    ),
+                    Err(err) => assert_eq!(
+                        err,
+                        Error::InvalidFieldValue {
+                            field: "mconfigptr",
+                            value: ptr,
+                            bitmask: !Mconfigptr::ALIGN_MASK,
+                        }
+                    ),
+                }
+
+                let aligned_ptr = ptr << Mconfigptr::ALIGN_SHIFT;
+                let aligned_mconfigptr = Mconfigptr::from_bits(aligned_ptr);
+
+                assert_eq!(aligned_mconfigptr.try_as_ptr(), Ok(aligned_ptr as *const _));
+                assert_eq!(aligned_mconfigptr.as_ptr(), aligned_ptr as *const _);
+            });
+    }
+}