rialo_s_define_syscall/
lib.rs

1#[cfg(not(target_arch = "riscv64"))]
2mod ebpf;
3
4#[cfg(target_arch = "riscv64")]
5mod risc_v;
6
7#[cfg(not(target_arch = "riscv64"))]
8pub mod definitions {
9    pub use crate::ebpf::*;
10}
11
12#[cfg(target_arch = "riscv64")]
13pub mod definitions {
14    pub use crate::risc_v::*;
15}
16
17/// Not part of the public API. Used by macros.
18#[cfg(target_arch = "riscv64")]
19#[doc(hidden)]
20pub mod __private {
21    pub use polkavm_derive::{self, default_abi};
22}
23
24#[cfg(all(target_feature = "static-syscalls", not(target_arch = "riscv64")))]
25#[macro_export]
26macro_rules! define_syscall {
27    (fn $name:ident($($arg:ident: $typ:ty),*) -> $ret:ty) => {
28        #[inline]
29        pub unsafe fn $name($($arg: $typ),*) -> $ret {
30            // this enum is used to force the hash to be computed in a const context
31            #[repr(usize)]
32            enum Syscall {
33                Code = $crate::sys_hash(stringify!($name)),
34            }
35
36            let syscall: extern "C" fn($($arg: $typ),*) -> $ret = core::mem::transmute(Syscall::Code);
37            syscall($($arg),*)
38        }
39
40    };
41    (fn $name:ident($($arg:ident: $typ:ty),*)) => {
42        define_syscall!(fn $name($($arg: $typ),*) -> ());
43    }
44}
45
46#[cfg(all(not(target_feature = "static-syscalls"), not(target_arch = "riscv64")))]
47#[macro_export]
48macro_rules! define_syscall {
49    (fn $name:ident($($arg:ident: $typ:ty),*) -> $ret:ty) => {
50        extern "C" {
51            pub fn $name($($arg: $typ),*) -> $ret;
52        }
53    };
54    (fn $name:ident($($arg:ident: $typ:ty),*)) => {
55        define_syscall!(fn $name($($arg: $typ),*) -> ());
56    }
57}
58
59/// RISC-V syscall definition macro using PolkaVM imports.
60///
61/// Unlike BPF which uses symbol resolution or hash-based dispatch,
62/// RISC-V/PolkaVM requires explicit import metadata via `#[polkavm_import]`.
63#[cfg(target_arch = "riscv64")]
64#[macro_export]
65macro_rules! define_syscall_riscv {
66    (fn $name:ident($($arg:ident: $typ:ty),*) -> $ret:ty) => {
67        // Workaround: `abi = ...` overrides the generated code's crate path (similar to
68        // `#[serde(crate = "...")]`), letting us point it at this crate's re-export
69        // so downstream crates don't need a direct `polkavm-derive` dependency.
70        // See: https://github.com/paritytech/polkavm/blob/master/crates/polkavm-derive-impl/src/import.rs
71        #[$crate::__private::polkavm_derive::polkavm_import(abi = $crate::__private::polkavm_derive::default_abi)]
72        extern "C" {
73            pub fn $name($($arg: $typ),*) -> $ret;
74        }
75    };
76    (fn $name:ident($($arg:ident: $typ:ty),*)) => {
77        $crate::define_syscall_riscv!(fn $name($($arg: $typ),*) -> ());
78    }
79}
80
81/// Stub for non-RISC-V targets to produce a clear compile error.
82#[cfg(not(target_arch = "riscv64"))]
83#[macro_export]
84macro_rules! define_syscall_riscv {
85    ($($tt:tt)*) => {
86        compile_error!("define_syscall_riscv! is only available on RISC-V targets");
87    };
88}
89
90#[cfg(all(target_feature = "static-syscalls", not(target_arch = "riscv64")))]
91pub const fn sys_hash(name: &str) -> usize {
92    murmur3_32(name.as_bytes(), 0) as usize
93}
94
95#[cfg(all(target_feature = "static-syscalls", not(target_arch = "riscv64")))]
96const fn murmur3_32(buf: &[u8], seed: u32) -> u32 {
97    const fn pre_mix(buf: [u8; 4]) -> u32 {
98        u32::from_le_bytes(buf)
99            .wrapping_mul(0xcc9e2d51)
100            .rotate_left(15)
101            .wrapping_mul(0x1b873593)
102    }
103
104    let mut hash = seed;
105
106    let mut i = 0;
107    while i < buf.len() / 4 {
108        let buf = [buf[i * 4], buf[i * 4 + 1], buf[i * 4 + 2], buf[i * 4 + 3]];
109        hash ^= pre_mix(buf);
110        hash = hash.rotate_left(13);
111        hash = hash.wrapping_mul(5).wrapping_add(0xe6546b64);
112
113        i += 1;
114    }
115
116    match buf.len() % 4 {
117        0 => {}
118        1 => {
119            hash = hash ^ pre_mix([buf[i * 4], 0, 0, 0]);
120        }
121        2 => {
122            hash = hash ^ pre_mix([buf[i * 4], buf[i * 4 + 1], 0, 0]);
123        }
124        3 => {
125            hash = hash ^ pre_mix([buf[i * 4], buf[i * 4 + 1], buf[i * 4 + 2], 0]);
126        }
127        _ => { /* unreachable!() */ }
128    }
129
130    hash = hash ^ buf.len() as u32;
131    hash = hash ^ (hash.wrapping_shr(16));
132    hash = hash.wrapping_mul(0x85ebca6b);
133    hash = hash ^ (hash.wrapping_shr(13));
134    hash = hash.wrapping_mul(0xc2b2ae35);
135    hash = hash ^ (hash.wrapping_shr(16));
136
137    hash
138}
rialo_s_define_syscall/lib.rs

rialo_s_define_syscall/
lib.rs
