Add spawn-thread example

Signed-off-by: Nick Spinale <[email protected]>

Cargo.toml

@@ -38,6 +38,7 @@ members = [
     "crates/examples/root-task/example-root-task",
     "crates/examples/root-task/example-root-task-without-runtime",
     "crates/examples/root-task/hello",
+    "crates/examples/root-task/spawn-thread",
     "crates/private/meta",
     "crates/private/support/sel4-simple-task/config-types",
     "crates/private/support/sel4-simple-task/rpc",

crates/examples/root-task/spawn-thread/Cargo.nix

@@ -0,0 +1,20 @@
+#
+# Copyright 2024, Colias Group, LLC
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+
+{ mk, versions, localCrates }:
+
+mk {
+  package.name = "spawn-thread";
+  dependencies = {
+    inherit (versions) cfg-if;
+    inherit (localCrates)
+      sel4
+      sel4-root-task
+      sel4-elf-header
+      sel4-initialize-tls
+    ;
+  };
+}

crates/examples/root-task/spawn-thread/Cargo.toml

@@ -0,0 +1,24 @@
+#
+# Copyright 2023, Colias Group, LLC
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+#
+# This file is generated from './Cargo.nix'. You can edit this file directly
+# if you are not using this project's Cargo manifest management tools.
+# See 'hacking/cargo-manifest-management/README.md' for more information.
+#
+
+[package]
+name = "spawn-thread"
+version = "0.1.0"
+authors = ["Nick Spinale <[email protected]>"]
+edition = "2021"
+license = "BSD-2-Clause"
+
+[dependencies]
+cfg-if = "1.0.0"
+sel4 = { path = "../../../sel4" }
+sel4-elf-header = { path = "../../../sel4-elf-header" }
+sel4-initialize-tls = { path = "../../../sel4-initialize-tls" }
+sel4-root-task = { path = "../../../sel4-root-task" }

crates/examples/root-task/spawn-thread/src/main.rs

@@ -0,0 +1,298 @@
+//
+// Copyright 2024, Colias Group, LLC
+//
+// SPDX-License-Identifier: BSD-2-Clause
+//
+
+#![no_std]
+#![no_main]
+#![feature(never_type)]
+
+extern crate alloc;
+
+use alloc::boxed::Box;
+use core::cell::UnsafeCell;
+use core::mem;
+use core::ops::Range;
+use core::panic::UnwindSafe;
+use core::ptr;
+
+use cfg_if::cfg_if;
+
+use sel4::SizedFrameType;
+use sel4_elf_header::{ElfHeader, PT_TLS};
+use sel4_initialize_tls::{TlsImage, TlsReservationLayout, UncheckedTlsImage};
+use sel4_root_task::{
+    abort, panicking::catch_unwind, root_task, set_global_allocator_mutex_notification, Never,
+};
+
+static SECONDARY_THREAD_STACK: Stack<4096> = Stack::new();
+
+static SECONDARY_THREAD_IPC_BUFFER_FRAME: IpcBufferFrame = IpcBufferFrame::new();
+
+#[root_task(heap_size = 1024 * 64)]
+fn main(bootinfo: &sel4::BootInfoPtr) -> sel4::Result<Never> {
+    sel4::debug_println!("In primary thread");
+
+    let (ut_ix, _desc) = bootinfo
+        .untyped_list()
+        .iter()
+        .enumerate()
+        .filter(|(_i, desc)| !desc.is_device())
+        .max_by_key(|(_i, desc)| desc.size_bits())
+        .unwrap();
+
+    let ut = bootinfo.untyped().index(ut_ix).cap();
+
+    let mut empty_slots = bootinfo
+        .empty()
+        .range()
+        .map(sel4::init_thread::Slot::from_index);
+
+    let mut create_object = |blueprint| {
+        let slot = empty_slots.next().unwrap();
+        ut.untyped_retype(
+            &blueprint,
+            &sel4::init_thread::slot::CNODE.cap().relative_self(),
+            slot.index(),
+            1,
+        )?;
+        Ok(slot.cap())
+    };
+
+    set_global_allocator_mutex_notification(
+        create_object(sel4::ObjectBlueprint::Notification)?
+            .downcast::<sel4::cap_type::Notification>(),
+    );
+
+    let inter_thread_nfn = create_object(sel4::ObjectBlueprint::Notification)?
+        .downcast::<sel4::cap_type::Notification>();
+
+    let secondary_thread_tcb =
+        create_object(sel4::ObjectBlueprint::Tcb)?.downcast::<sel4::cap_type::Tcb>();
+
+    secondary_thread_tcb.tcb_configure(
+        sel4::init_thread::slot::NULL.cptr(),
+        sel4::init_thread::slot::CNODE.cap(),
+        sel4::CNodeCapData::new(0, 0),
+        sel4::init_thread::slot::VSPACE.cap(),
+        SECONDARY_THREAD_IPC_BUFFER_FRAME.ptr() as sel4::Word,
+        SECONDARY_THREAD_IPC_BUFFER_FRAME.cap(bootinfo),
+    )?;
+
+    let f = SecondaryThreadFn::new(move || {
+        unsafe { sel4::set_ipc_buffer(SECONDARY_THREAD_IPC_BUFFER_FRAME.ptr().as_mut().unwrap()) }
+        sel4::debug_println!("In secondary thread");
+        inter_thread_nfn.signal();
+        secondary_thread_tcb.tcb_suspend().unwrap();
+        unreachable!()
+    });
+
+    secondary_thread_tcb.tcb_write_all_registers(true, &mut create_user_context(f))?;
+
+    inter_thread_nfn.wait();
+
+    sel4::debug_println!("TEST_PASS");
+
+    sel4::init_thread::suspend_self()
+}
+
+fn create_user_context(f: SecondaryThreadFn) -> sel4::UserContext {
+    let mut ctx = sel4::UserContext::default();
+
+    *ctx.sp_mut() = SECONDARY_THREAD_STACK.top().try_into().unwrap();
+    *ctx.pc_mut() = secondary_thread_entrypoint as sel4::Word;
+
+    *user_context_arg_mut(&mut ctx, 0) = f.into_arg();
+
+    let tls_reservation = TlsReservation::new(&get_tls_image());
+    *user_context_thread_pointer_mut(&mut ctx) = tls_reservation.thread_pointer() as sel4::Word;
+    mem::forget(tls_reservation);
+
+    cfg_if! {
+        if #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))] {
+            ctx.inner_mut().gp = riscv_get_gp();
+        }
+    }
+
+    ctx
+}
+
+fn user_context_arg_mut(ctx: &mut sel4::UserContext, i: sel4::Word) -> &mut sel4::Word {
+    cfg_if! {
+        if #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))] {
+            ctx.gpr_a_mut(i)
+        } else {
+            ctx.gpr_mut(i)
+        }
+    }
+}
+
+fn user_context_thread_pointer_mut(ctx: &mut sel4::UserContext) -> &mut sel4::Word {
+    cfg_if! {
+        if #[cfg(target_arch = "aarch64")] {
+            &mut ctx.inner_mut().tpidr_el0
+        } else if #[cfg(target_arch = "arm")] {
+            &mut ctx.inner_mut().tpidrurw
+        } else if #[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))] {
+            &mut ctx.inner_mut().tp
+        } else if #[cfg(target_arch = "x86_64")] {
+            &mut ctx.inner_mut().fs_base
+        } else {
+            compile_error!("unsupported architecture");
+        }
+    }
+}
+
+#[cfg(any(target_arch = "riscv32", target_arch = "riscv64"))]
+fn riscv_get_gp() -> sel4::Word {
+    let val: sel4::Word;
+    unsafe {
+        core::arch::asm!("mv {}, gp", out(reg) val);
+    }
+    val
+}
+
+// // //
+
+unsafe extern "C" fn secondary_thread_entrypoint(arg: sel4::Word) -> ! {
+    let f = SecondaryThreadFn::from_arg(arg);
+    let _ = catch_unwind(|| f.run());
+    abort!("secondary thread panicked")
+}
+
+struct SecondaryThreadFn(Box<dyn FnOnce() -> ! + UnwindSafe + Send + 'static>);
+
+impl SecondaryThreadFn {
+    fn new(f: impl FnOnce() -> ! + UnwindSafe + Send + 'static) -> Self {
+        Self(Box::new(f))
+    }
+
+    fn run(self) -> ! {
+        (self.0)()
+    }
+
+    fn into_arg(self) -> sel4::Word {
+        Box::into_raw(Box::new(self)) as sel4::Word
+    }
+
+    unsafe fn from_arg(arg: sel4::Word) -> Self {
+        *Box::from_raw(arg as *mut Self)
+    }
+}
+
+// // //
+
+struct TlsReservation {
+    start: *mut u8,
+    layout: TlsReservationLayout,
+}
+
+impl TlsReservation {
+    fn new(tls_image: &TlsImage) -> Self {
+        let layout = tls_image.reservation_layout();
+        let start = unsafe { ::alloc::alloc::alloc(layout.footprint()) };
+        unsafe {
+            tls_image.initialize_tls_reservation(start);
+        };
+        Self { start, layout }
+    }
+
+    fn thread_pointer(&self) -> usize {
+        (self.start as usize) + self.layout.thread_pointer_offset()
+    }
+}
+
+impl Drop for TlsReservation {
+    fn drop(&mut self) {
+        unsafe {
+            ::alloc::alloc::dealloc(self.start, self.layout.footprint());
+        }
+    }
+}
+
+fn get_tls_image() -> TlsImage {
+    extern "C" {
+        static __ehdr_start: ElfHeader;
+    }
+    let phdrs = unsafe {
+        assert!(__ehdr_start.check_magic());
+        __ehdr_start.locate_phdrs()
+    };
+    let phdr = phdrs.iter().find(|phdr| phdr.p_type == PT_TLS).unwrap();
+    let unchecked = UncheckedTlsImage {
+        vaddr: phdr.p_vaddr,
+        filesz: phdr.p_filesz,
+        memsz: phdr.p_memsz,
+        align: phdr.p_align,
+    };
+    unchecked.check().unwrap()
+}
+
+// // //
+
+#[repr(C, align(16))]
+struct Stack<const N: usize>(UnsafeCell<[u8; N]>);
+
+unsafe impl<const N: usize> Sync for Stack<N> {}
+
+impl<const N: usize> Stack<N> {
+    const fn new() -> Self {
+        Self(UnsafeCell::new([0; N]))
+    }
+
+    fn top(&self) -> usize {
+        (self.0.get() as usize) + N
+    }
+}
+
+// // //
+
+#[repr(C, align(4096))]
+struct IpcBufferFrame(UnsafeCell<[u8; GRANULE_SIZE]>);
+
+unsafe impl Sync for IpcBufferFrame {}
+
+impl IpcBufferFrame {
+    const fn new() -> Self {
+        Self(UnsafeCell::new([0; GRANULE_SIZE]))
+    }
+
+    const fn ptr(&self) -> *mut sel4::IpcBuffer {
+        self.0.get().cast()
+    }
+
+    fn cap(&self, bootinfo: &sel4::BootInfo) -> sel4::Granule {
+        get_user_image_frame_slot(bootinfo, self.ptr() as usize).cap()
+    }
+}
+
+fn get_user_image_frame_slot(
+    bootinfo: &sel4::BootInfo,
+    addr: usize,
+) -> sel4::init_thread::Slot<sel4::cap_type::Granule> {
+    assert_eq!(addr % GRANULE_SIZE, 0);
+    let user_image_footprint = get_user_image_footprint();
+    let num_user_frames = bootinfo.user_image_frames().len();
+    assert_eq!(user_image_footprint.len(), num_user_frames * GRANULE_SIZE);
+    let ix = (addr - user_image_footprint.start) / GRANULE_SIZE;
+    bootinfo.user_image_frames().index(ix)
+}
+
+fn get_user_image_footprint() -> Range<usize> {
+    extern "C" {
+        static __executable_start: u64;
+        static _end: u64;
+    }
+    unsafe {
+        let start = round_down(ptr::addr_of!(__executable_start) as usize, GRANULE_SIZE);
+        let end = (ptr::addr_of!(_end) as usize).next_multiple_of(GRANULE_SIZE);
+        start..end
+    }
+}
+
+const fn round_down(n: usize, b: usize) -> usize {
+    n - n % b
+}
+
+const GRANULE_SIZE: usize = sel4::cap_type::Granule::FRAME_SIZE.bytes();