xous-kernel/xous-riscv/src/asm.rs

78 lines
2.9 KiB
Rust

//! Assembly instructions
macro_rules! instruction {
($(#[$attr:meta])*, $fnname:ident, $asm:expr, $asm_fn:ident) => (
$(#[$attr])*
#[inline]
pub unsafe fn $fnname() {
match () {
#[cfg(all(riscv, feature = "inline-asm"))]
() => asm!($asm :::: "volatile"),
#[cfg(all(riscv, not(feature = "inline-asm")))]
() => {
extern "C" {
fn $asm_fn();
}
$asm_fn();
}
#[cfg(not(riscv))]
() => unimplemented!(),
}
}
)
}
instruction!(
/// `EBREAK` instruction wrapper
///
/// Generates a breakpoint exception.
, ebreak, "ebreak", __ebreak);
instruction!(
/// `WFI` instruction wrapper
///
/// Provides a hint to the implementation that the current hart can be stalled until an interrupt might need servicing.
/// The WFI instruction is just a hint, and a legal implementation is to implement WFI as a NOP.
, wfi, "wfi", __wfi);
instruction!(
/// `SFENCE.VMA` instruction wrapper (all address spaces and page table levels)
///
/// Synchronizes updates to in-memory memory-management data structures with current execution.
/// Instruction execution causes implicit reads and writes to these data structures; however, these implicit references
/// are ordinarily not ordered with respect to loads and stores in the instruction stream.
/// Executing an `SFENCE.VMA` instruction guarantees that any stores in the instruction stream prior to the
/// `SFENCE.VMA` are ordered before all implicit references subsequent to the `SFENCE.VMA`.
, sfence_vma_all, "sfence.vma", __sfence_vma_all);
/// `SFENCE.VMA` instruction wrapper
///
/// Synchronizes updates to in-memory memory-management data structures with current execution.
/// Instruction execution causes implicit reads and writes to these data structures; however, these implicit references
/// are ordinarily not ordered with respect to loads and stores in the instruction stream.
/// Executing an `SFENCE.VMA` instruction guarantees that any stores in the instruction stream prior to the
/// `SFENCE.VMA` are ordered before all implicit references subsequent to the `SFENCE.VMA`.
#[inline]
#[allow(unused_variables)]
pub unsafe fn sfence_vma(asid: usize, addr: usize) {
match () {
#[cfg(all(riscv, feature = "inline-asm"))]
() => asm!("sfence.vma $0, $1" :: "r"(asid), "r"(addr) :: "volatile"),
#[cfg(all(riscv, not(feature = "inline-asm")))]
() => {
extern "C" {
fn __sfence_vma(asid: usize, addr: usize);
}
__sfence_vma(asid, addr);
}
#[cfg(not(riscv))]
() => unimplemented!(),
}
}