arch: add powerpc32 support

.github/workflows/rust.yml

@@ -49,6 +49,9 @@ jobs:
             build_std: true
           - target: i686-unknown-linux-gnu
             toolchain: stable
+          # powerpc uses experimental asm features
+          - target: powerpc-unknown-linux-gnu
+            toolchain: nightly
 
     steps:
     - name: "Checkout"

crates/asm/src/lib.rs

@@ -6,13 +6,14 @@
 //! faster?
 //!
 //! Supports `x86_64`, `aarch64`, `riscv64`, `loongarch64`, `s390x`,
-//! `powerpc64`, `arm` (armv7), `riscv32`, `sparc64`, `mips64`, and `x86`
+//! `powerpc64`, `arm` (armv7), `riscv32`, `sparc64`, `mips64`, `x86` (i686),
-//! (i686) architectures.
+//! and `powerpc` (ppc32) architectures.
 
 #![no_std]
 #![cfg_attr(
   any(
     target_arch = "powerpc64",
+    target_arch = "powerpc",
     target_arch = "sparc64",
     target_arch = "mips64"
   ),
@@ -31,11 +32,13 @@
   target_arch = "riscv32",
   target_arch = "sparc64",
   target_arch = "mips64",
-  target_arch = "x86"
+  target_arch = "x86",
+  target_arch = "powerpc"
 )))]
 compile_error!(
   "Unsupported architecture: only x86_64, aarch64, riscv64, loongarch64, \
-   s390x, powerpc64, arm, riscv32, sparc64, mips64, and x86 are supported"
+   s390x, powerpc64, arm, riscv32, sparc64, mips64, x86, and powerpc are \
+   supported"
 );
 
 // Per-arch syscall implementations live in their own module files.
@@ -72,6 +75,9 @@ mod arch;
 #[cfg(target_arch = "x86")]
 #[path = "x86.rs"]
 mod arch;
+#[cfg(target_arch = "powerpc")]
+#[path = "powerpc.rs"]
+mod arch;
 
 /// Copies `n` bytes from `src` to `dest`.
 ///
@@ -310,6 +316,7 @@ pub unsafe fn sys_uname(buf: *mut UtsNameBuf) -> i32 {
   target_arch = "arm",
   target_arch = "riscv32",
   target_arch = "x86",
+  target_arch = "powerpc",
   target_arch = "mips64"
 )))]
 pub struct StatfsBuf {
@@ -352,7 +359,12 @@ pub struct StatfsBuf {
 /// on armv7 `statfs64(2)` has 32-bit word fields; see
 /// https://github.com/torvalds/linux/blob/v6.19/include/uapi/asm-generic/statfs.h
 #[repr(C)]
-#[cfg(any(target_arch = "arm", target_arch = "riscv32", target_arch = "x86"))]
+#[cfg(any(
+  target_arch = "arm",
+  target_arch = "riscv32",
+  target_arch = "x86",
+  target_arch = "powerpc"
+))]
 pub struct StatfsBuf {
   pub f_type:    u32,
   pub f_bsize:   u32,
@@ -463,7 +475,8 @@ pub fn read_file_fast(path: &str, buffer: &mut [u8]) -> Result<usize, i32> {
 #[cfg(not(any(
   target_arch = "arm",
   target_arch = "riscv32",
-  target_arch = "x86"
+  target_arch = "x86",
+  target_arch = "powerpc"
 )))]
 pub struct SysInfo {
   pub uptime:    i64,
@@ -488,7 +501,12 @@ pub struct SysInfo {
 /// on armv7 `__kernel_long_t` is 4 bytes; see
 /// https://github.com/torvalds/linux/blob/v6.19/include/uapi/linux/sysinfo.h
 #[repr(C)]
-#[cfg(any(target_arch = "arm", target_arch = "riscv32", target_arch = "x86"))]
+#[cfg(any(
+  target_arch = "arm",
+  target_arch = "riscv32",
+  target_arch = "x86",
+  target_arch = "powerpc"
+))]
 pub struct SysInfo {
   pub uptime:    i32,
   pub loads:     [u32; 3],

crates/asm/src/powerpc.rs

@@ -0,0 +1,180 @@
+//! Syscall implementations for `powerpc`.
+
+use super::{StatfsBuf, SysInfo, UtsNameBuf};
+
+pub(super) unsafe fn sys_open(path: *const u8, flags: i32) -> i32 {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 5i32 => _,  // SYS_open
+      inlateout("r3") path => ret,
+      inlateout("r4") flags => _,
+      inlateout("r5") 0i32 => _,
+      out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret
+  }
+}
+
+pub(super) unsafe fn sys_read(fd: i32, buf: *mut u8, count: usize) -> isize {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 3i32 => _,  // SYS_read
+      inlateout("r3") fd => ret,
+      inlateout("r4") buf => _,
+      inlateout("r5") count => _,
+      out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret as isize
+  }
+}
+
+pub(super) unsafe fn sys_write(fd: i32, buf: *const u8, count: usize) -> isize {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 4i32 => _,  // SYS_write
+      inlateout("r3") fd => ret,
+      inlateout("r4") buf => _,
+      inlateout("r5") count => _,
+      out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret as isize
+  }
+}
+
+pub(super) unsafe fn sys_close(fd: i32) -> i32 {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 6i32 => _,  // SYS_close
+      inlateout("r3") fd => ret,
+      out("r4") _, out("r5") _, out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret
+  }
+}
+
+pub(super) unsafe fn sys_uname(buf: *mut UtsNameBuf) -> i32 {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 122i32 => _,  // SYS_newuname
+      inlateout("r3") buf => ret,
+      out("r4") _, out("r5") _, out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret
+  }
+}
+
+pub(super) unsafe fn sys_statfs(path: *const u8, buf: *mut StatfsBuf) -> i32 {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 252i32 => _,  // SYS_statfs64
+      inlateout("r3") path => ret,
+      inlateout("r4") core::mem::size_of::<StatfsBuf>() => _,
+      inlateout("r5") buf => _,
+      out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret
+  }
+}
+
+pub(super) unsafe fn sys_sysinfo(info: *mut SysInfo) -> i64 {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 116_i32 => _, // __NR_sysinfo
+      inlateout("r3") info => ret,
+      out("r4") _, out("r5") _, out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    i64::from(ret)
+  }
+}
+
+pub(super) unsafe fn sys_sched_getaffinity(
+  pid: i32,
+  mask_size: usize,
+  mask: *mut u8,
+) -> i32 {
+  unsafe {
+    let ret: i32;
+    core::arch::asm!(
+      "sc",
+      "bns+ 2f",
+      "neg 3, 3",
+      "2:",
+      inlateout("r0") 223i32 => _,  // __NR_sched_getaffinity
+      inlateout("r3") pid => ret,
+      inlateout("r4") mask_size => _,
+      inlateout("r5") mask => _,
+      out("r6") _, out("r7") _, out("r8") _,
+      out("r9") _, out("r10") _, out("r11") _, out("r12") _,
+      out("cr0") _,
+      options(nostack)
+    );
+    ret
+  }
+}
+
+pub(super) unsafe fn sys_exit(code: i32) -> ! {
+  unsafe {
+    core::arch::asm!(
+      "li 0, 1",  // SYS_exit
+      "sc",
+      in("r3") code,
+      options(noreturn, nostack)
+    );
+  }
+}

microfetch/src/main.rs

@@ -3,6 +3,7 @@
 #![cfg_attr(
   any(
     target_arch = "powerpc64",
+    target_arch = "powerpc",
     target_arch = "sparc64",
     target_arch = "mips64"
   ),
@@ -137,6 +138,22 @@ unsafe extern "C" fn _start() {
   );
 }
 
+// ppc32 has no function descriptors; entry is direct code like ELFv2.
+#[cfg(target_arch = "powerpc")]
+#[unsafe(no_mangle)]
+#[unsafe(naked)]
+unsafe extern "C" fn _start() {
+  naked_asm!(
+    "mr 3, 1",          // first arg = initial sp (argc/argv)
+    "clrrwi 1, 1, 4",   // align sp to 16 bytes
+    "stwu 1, -64(1)",   // reserve a frame with back-chain
+    "bl {entry_rust}",
+    "li 0, 1",          // SYS_exit
+    "sc",
+    entry_rust = sym entry_rust,
+  );
+}
+
 // On ELFv1, the ELF entry point must be a function descriptor
 // in .opd whose first word is the real code address. We emit both manually via
 // `global_asm` so the kernel reads the descriptor and jumps into `_start_impl`.