GKaszewski/k-os
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refactor(adapter-riscv): split kmain into boot/, devices/ modules

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kmain is now 20 lines — six function calls:

  hardware::init        → BSS, MMU, traps, timer, PLIC, kernel
  loader::load_init     → read init.elf, create process, map ELF
  loader::load_server   → read server ELF, create process, map ELF
  storage_setup         → VirtIO block re-init, shared buffer, phys-info
  gpu_setup             → VirtIO GPU init, framebuffer alloc, phys-info
  caps::grant_all       → endpoints, capability grants

New modules:
  boot/hardware.rs   — hardware init (BSS, MMU, traps, kernel)
  boot/loader.rs     — ELF loading, thread setup, enter_userspace
  boot/caps.rs       — endpoint creation, capability grants
  devices/storage_setup.rs — VirtIO block for storage server
  devices/gpu_setup.rs     — VirtIO GPU for display server

All unsafe contained in hw/, mmu/, trap/. Boot and device
modules call safe wrappers.
This commit is contained in:
Gabriel Kaszewski
2026-10-18 13:19:16 +02:00
parent 5766c6f7f7
commit 8d53fa9ac5
8 changed files with 495 additions and 461 deletions
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475
crates/adapter-riscv/src/main.rs
View File

@@ -2,7 +2,9 @@
#![no_main]
mod board;
mod boot;
mod boot_fs;
mod devices;
mod hw;
mod kernel_cell;
mod mmu;
@@ -12,7 +14,6 @@ mod trap;
use core::arch::global_asm;
use hw::uart::Uart;
use kernel_cell::KernelCell;
use types::id::{ProcessId, ThreadId};
static KERNEL: KernelCell<kernel::Kernel<platform::RiscVPlatform>> = KernelCell::uninit();
@@ -33,480 +34,32 @@ spin:
"#
);
unsafe extern "C" {
static _bss_start: u8;
static _bss_end: u8;
static _heap_start: u8;
}
fn zero_bss() {
unsafe {
let start = &_bss_start as *const u8 as *mut u8;
let end = &_bss_end as *const u8 as *mut u8;
let len = end as usize - start as usize;
core::ptr::write_bytes(start, 0, len);
}
}
const USER_VA_BASE: usize = 0x10000;
const MAX_FILE_SIZE: usize = 64 * 1024;
const SHARED_BUF_VA: usize = 0x30000;
const SHARED_BUF_PAGES: usize = 16;
const STORAGE_VIRTIO_VA: usize = 0x20000;
const STORAGE_VQUEUE_VA: usize = 0x21000;
const STORAGE_REQHDR_VA: usize = 0x23000;
const STORAGE_PHYSINFO_VA: usize = 0x24000;
const DISPLAY_GPU_VA: usize = 0x20000;
const DISPLAY_VQUEUE_VA: usize = 0x21000;
const DISPLAY_CMDBUF_VA: usize = 0x23000;
const DISPLAY_PHYSINFO_VA: usize = 0x24000;
const DISPLAY_FB_VA: usize = 0x100000;
const DISPLAY_FB_WIDTH: u32 = 640;
const DISPLAY_FB_HEIGHT: u32 = 480;
const DISPLAY_FB_BPP: usize = 4;
const DISPLAY_FB_PAGES: usize = (DISPLAY_FB_WIDTH as usize * DISPLAY_FB_HEIGHT as usize * DISPLAY_FB_BPP + 4095) / 4096;
#[unsafe(no_mangle)]
extern "C" fn kmain() -> ! {
zero_bss();
let uart = Uart::new();
uart.write_str("k-os: booted on RISC-V\n");
let heap_start = unsafe { &_heap_start as *const u8 as usize };
mmu::init_allocator(heap_start);
let kernel_pt = mmu::init_kernel_page_table();
mmu::activate(kernel_pt);
uart.write_str("k-os: MMU enabled (Sv39)\n");
let kernel_pt = boot::hardware::init(&uart);
let mut blk = boot::hardware::probe_block_device(&uart)
.unwrap_or_else(|| halt(&uart, "no block device"));
trap::init();
hw::timer::init();
hw::plic::Plic::init();
uart.write_str("k-os: traps and timer initialized\n");
let riscv_platform = platform::RiscVPlatform::new(kernel_pt as *const mmu::PageTable as usize);
let pool = domain::memory::page_pool::PagePool::new(
types::address::PhysicalAddress::from_raw(board::USER_POOL_BASE),
board::USER_POOL_PAGES,
);
KERNEL.init(kernel::Kernel::new(riscv_platform, pool));
// --- Read init + storage from disk ---
let mut blk = hw::virtio_blk::VirtioBlk::probe();
if blk.is_none() {
halt(&uart, "no block device");
}
uart.write_str("k-os: VirtIO block device found\n");
// Boot init (pid 0) — kern.boot() grants ProcessCreate cap at slot 0
let (init_pid, init_tid) = kernel_ref()
.boot(types::bounded::Priority::DEFAULT, types::time::TimeSlice::DEFAULT)
.unwrap_or_else(|_| halt(&uart, "boot failed"));
let init_entry = load_elf_into_process(&uart, blk.as_mut(), kernel_pt, init_pid, b"init.elf");
if init_entry == 0 { halt(&uart, "init.elf not found"); }
setup_thread(init_tid, init_entry);
uart.write_str("k-os: init loaded\n");
// Load storage server
let storage_pid = kernel_ref().create_process_internal()
.unwrap_or_else(|| halt(&uart, "storage process failed"));
let storage_entry = load_elf_into_process(&uart, blk.as_mut(), kernel_pt, storage_pid, b"storage.elf");
if storage_entry == 0 { halt(&uart, "storage.elf not found"); }
let storage_tid = kernel_ref().spawn_thread_internal(storage_pid)
.unwrap_or_else(|| halt(&uart, "storage thread failed"));
setup_thread(storage_tid, storage_entry);
uart.write_str("k-os: storage loaded\n");
// Load display server
let display_pid = kernel_ref().create_process_internal()
.unwrap_or_else(|| halt(&uart, "display process failed"));
let display_entry = load_elf_into_process(&uart, blk.as_mut(), kernel_pt, display_pid, b"display.elf");
if display_entry == 0 { halt(&uart, "display.elf not found"); }
let display_tid = kernel_ref().spawn_thread_internal(display_pid)
.unwrap_or_else(|| halt(&uart, "display thread failed"));
setup_thread(display_tid, display_entry);
uart.write_str("k-os: display loaded\n");
// Done reading from disk — drop the adapter's VirtIO driver
let virtio_base = blk.as_ref().map(|b| b.base()).unwrap_or(0);
let (init, _) = boot::loader::load_init(&uart, &mut blk, kernel_pt);
let storage = boot::loader::load_server(&uart, &mut blk, kernel_pt, b"storage.elf", "storage");
let display = boot::loader::load_server(&uart, &mut blk, kernel_pt, b"display.elf", "display");
let virtio_base = blk.base();
drop(blk);
// --- Set up VirtIO for storage server ---
let storage_pt = kernel_ref().platform_mut().page_table_for(storage_pid);
let storage_pt_ref = unsafe { &mut *(storage_pt as *mut mmu::PageTable) };
devices::storage_setup::configure(&uart, init.pid, storage.pid, virtio_base);
devices::gpu_setup::configure(&uart, display.pid);
boot::caps::grant_all(&uart, init.pid, storage.pid, display.pid);
// Map VirtIO MMIO into storage's address space
mmu::map(storage_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(STORAGE_VIRTIO_VA),
pa: types::address::PhysicalAddress::from_raw(virtio_base),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
// Allocate virtqueue pages (2 pages) and map into storage
let vqueue_phys = mmu::allocator::alloc_zeroed_page();
mmu::allocator::alloc_zeroed_page(); // second page (contiguous)
for i in 0..2usize {
mmu::map(storage_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(STORAGE_VQUEUE_VA + i * 4096),
pa: types::address::PhysicalAddress::from_raw(vqueue_phys + i * 4096),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
}
// Allocate request header page and map into storage
let reqhdr_phys = mmu::allocator::alloc_zeroed_page();
mmu::map(storage_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(STORAGE_REQHDR_VA),
pa: types::address::PhysicalAddress::from_raw(reqhdr_phys),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
// Allocate phys info page — storage reads DMA addresses from here
let physinfo_phys = mmu::allocator::alloc_zeroed_page();
mmu::map(storage_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(STORAGE_PHYSINFO_VA),
pa: types::address::PhysicalAddress::from_raw(physinfo_phys),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
// Write physical addresses: [req_hdr_pa, status_pa, sector_buf_pa]
unsafe {
let info = physinfo_phys as *mut u64;
core::ptr::write_volatile(info, reqhdr_phys as u64); // req_hdr_pa
core::ptr::write_volatile(info.add(1), (reqhdr_phys + 16) as u64); // status_pa
core::ptr::write_volatile(info.add(2), (reqhdr_phys + 32) as u64); // sector_buf_pa
}
// Re-initialize VirtIO device with storage's virtqueue
reinit_virtio_for_storage(virtio_base, vqueue_phys);
uart.write_str("k-os: VirtIO configured for storage\n");
// --- Set up VirtIO GPU for display server ---
let display_pt = kernel_ref().platform_mut().page_table_for(display_pid);
let display_pt_ref = unsafe { &mut *(display_pt as *mut mmu::PageTable) };
if let Some(gpu) = hw::virtio_gpu::VirtioGpu::probe() {
let gpu_base = gpu.base();
// Map GPU MMIO into display's address space
mmu::map(display_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(DISPLAY_GPU_VA),
pa: types::address::PhysicalAddress::from_raw(gpu_base),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
// Allocate GPU virtqueue (2 pages)
let gpu_vq_phys = mmu::allocator::alloc_zeroed_page();
mmu::allocator::alloc_zeroed_page();
for i in 0..2usize {
mmu::map(display_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(DISPLAY_VQUEUE_VA + i * 4096),
pa: types::address::PhysicalAddress::from_raw(gpu_vq_phys + i * 4096),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
}
// Allocate command buffer (1 page)
let gpu_cmd_phys = mmu::allocator::alloc_zeroed_page();
mmu::map(display_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(DISPLAY_CMDBUF_VA),
pa: types::address::PhysicalAddress::from_raw(gpu_cmd_phys),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
// Allocate framebuffer (300 pages, contiguous)
let fb_phys = mmu::allocator::alloc_zeroed_page();
for _ in 1..DISPLAY_FB_PAGES {
mmu::allocator::alloc_zeroed_page();
}
for i in 0..DISPLAY_FB_PAGES {
mmu::map(display_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(DISPLAY_FB_VA + i * 4096),
pa: types::address::PhysicalAddress::from_raw(fb_phys + i * 4096),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
}
// Write phys-info for display server
let gpu_physinfo = mmu::allocator::alloc_zeroed_page();
mmu::map(display_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(DISPLAY_PHYSINFO_VA),
pa: types::address::PhysicalAddress::from_raw(gpu_physinfo),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
unsafe {
let info = gpu_physinfo as *mut u64;
core::ptr::write_volatile(info, gpu_cmd_phys as u64);
core::ptr::write_volatile(info.add(1), (gpu_cmd_phys + 512) as u64); // response area
core::ptr::write_volatile(info.add(2), fb_phys as u64);
core::ptr::write_volatile(info.add(3), DISPLAY_FB_WIDTH as u64);
core::ptr::write_volatile(info.add(4), DISPLAY_FB_HEIGHT as u64);
}
// Initialize GPU device and set up framebuffer
gpu.init_device(gpu_vq_phys);
gpu.setup_framebuffer(gpu_cmd_phys, gpu_vq_phys, fb_phys, DISPLAY_FB_WIDTH, DISPLAY_FB_HEIGHT);
uart.write_str("k-os: VirtIO GPU configured\n");
} else {
uart.write_str("k-os: no GPU found (display will be headless)\n");
}
// --- Allocate shared buffer and map into both processes ---
let init_pt = kernel_ref().platform_mut().page_table_for(init_pid);
let init_pt_ref = unsafe { &mut *(init_pt as *mut mmu::PageTable) };
for i in 0..SHARED_BUF_PAGES {
let page = mmu::allocator::alloc_zeroed_page();
let va = SHARED_BUF_VA + i * 4096;
mmu::map(init_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(va),
pa: types::address::PhysicalAddress::from_raw(page),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
mmu::map(storage_pt_ref, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(va),
pa: types::address::PhysicalAddress::from_raw(page),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
}
uart.write_str("k-os: shared buffer mapped\n");
// --- Grant capabilities ---
let all_perms = types::permission::PermissionSet::empty()
.with(types::permission::Permission::Read)
.with(types::permission::Permission::Write)
.with(types::permission::Permission::Execute)
.with(types::permission::Permission::Delegate);
// Create storage endpoint
let storage_ep = kernel_ref().create_endpoint()
.unwrap_or_else(|_| halt(&uart, "endpoint create failed"));
// Init caps: slot 0 = ProcessCreate (from boot), slot 1 = Process(storage), slot 2 = Endpoint
kernel_ref().grant_capability(
init_pid,
domain::resource::Resource::Process(storage_pid),
all_perms,
).unwrap_or_else(|_| halt(&uart, "grant Process cap failed"));
kernel_ref().grant_capability(
init_pid,
domain::resource::Resource::Endpoint(storage_ep),
all_perms,
).unwrap_or_else(|_| halt(&uart, "grant Endpoint to init failed"));
// Storage caps: slot 0 = Endpoint (Read+Execute for receive/send)
let storage_ep_perms = types::permission::PermissionSet::empty()
.with(types::permission::Permission::Read)
.with(types::permission::Permission::Execute);
kernel_ref().grant_capability(
storage_pid,
domain::resource::Resource::Endpoint(storage_ep),
storage_ep_perms,
).unwrap_or_else(|_| halt(&uart, "grant Endpoint to storage failed"));
// Create display endpoint
let display_ep = kernel_ref().create_endpoint()
.unwrap_or_else(|_| halt(&uart, "display endpoint failed"));
// Display caps: slot 0 = Endpoint (Read+Execute)
kernel_ref().grant_capability(
display_pid,
domain::resource::Resource::Endpoint(display_ep),
storage_ep_perms, // same Read+Execute
).unwrap_or_else(|_| halt(&uart, "grant Endpoint to display failed"));
// Init also gets display endpoint (slot 3) and display process cap (slot 4) for IPC
kernel_ref().grant_capability(
init_pid,
domain::resource::Resource::Endpoint(display_ep),
all_perms,
).unwrap_or_else(|_| halt(&uart, "grant display ep to init failed"));
kernel_ref().grant_capability(
init_pid,
domain::resource::Resource::Process(display_pid),
all_perms,
).unwrap_or_else(|_| halt(&uart, "grant display proc to init failed"));
uart.write_str("k-os: capabilities granted\n");
// --- Enter userspace with init, passing shared_buf VA in a0 ---
uart.write_str("k-os: entering userspace\n");
enter_userspace(init_pid, init_entry, SHARED_BUF_VA);
boot::loader::enter_userspace(init.pid, init.entry, SHARED_BUF_VA);
}
fn reinit_virtio_for_storage(base: usize, vqueue_phys: usize) {
use hw::virtio_blk::{mmio_read, mmio_write};
// Reset
mmio_write(base, 0x070, 0);
while mmio_read(base, 0x070) != 0 {}
// Acknowledge + Driver
mmio_write(base, 0x070, 1); // ACK
mmio_write(base, 0x070, mmio_read(base, 0x070) | 2); // DRIVER
// Legacy: set guest page size
mmio_write(base, 0x028, 4096);
// Features: accept none
mmio_write(base, 0x014, 0);
mmio_write(base, 0x024, 0);
mmio_write(base, 0x020, 0);
// Queue 0 setup
mmio_write(base, 0x030, 0); // select queue 0
let queue_max = mmio_read(base, 0x034);
let queue_num = 8u32.min(queue_max);
mmio_write(base, 0x038, queue_num);
// Point device to storage's virtqueue (physical page number)
mmio_write(base, 0x040, (vqueue_phys / 4096) as u32);
// DRIVER_OK
mmio_write(base, 0x070, mmio_read(base, 0x070) | 4);
}
fn load_elf_into_process(
_uart: &Uart,
blk: Option<&mut hw::virtio_blk::VirtioBlk>,
kernel_pt: &mmu::PageTable,
pid: ProcessId,
filename: &[u8],
) -> usize {
let buf_base = mmu::allocator::alloc_zeroed_page();
let file_pages = MAX_FILE_SIZE / 4096;
for _ in 1..file_pages {
mmu::allocator::alloc_zeroed_page();
}
let buf = unsafe { core::slice::from_raw_parts_mut(buf_base as *mut u8, MAX_FILE_SIZE) };
let file_size = match blk {
Some(b) => boot_fs::read_file_from_disk(b, filename, buf).unwrap_or(0),
None => 0,
};
if file_size == 0 { return 0; }
let elf_info = match elf::parse(&buf[..file_size]) {
Ok(info) => info,
Err(_) => return 0,
};
let user_pt = mmu::create_user_page_table(
kernel_pt,
types::address::PhysicalAddress::from_raw(0),
0,
types::address::VirtualAddress::from_raw(USER_VA_BASE),
);
for segment in elf_info.segments() {
let page_start = segment.vaddr & !0xFFF;
let offset_in_page = segment.vaddr & 0xFFF;
let total_size = offset_in_page + segment.mem_size;
let seg_pages = (total_size + 4095) / 4096;
for p in 0..seg_pages {
let page = mmu::allocator::alloc_zeroed_page();
let page_va = page_start + p * 4096;
let seg_file_start = if p == 0 { 0 } else { p * 4096 - offset_in_page };
let dest_off = if p == 0 { offset_in_page } else { 0 };
let copy_len = if seg_file_start < segment.file_size {
(segment.file_size - seg_file_start).min(4096 - dest_off)
} else { 0 };
if copy_len > 0 {
let src = segment.file_offset + seg_file_start;
if src + copy_len <= file_size {
unsafe {
core::ptr::copy_nonoverlapping(
buf.as_ptr().add(src),
(page as *mut u8).add(dest_off),
copy_len,
);
}
}
}
let flags = if segment.flags.execute {
mmu::Sv39Flags::user_rx()
} else if segment.flags.write {
mmu::Sv39Flags::user_rw()
} else {
mmu::Sv39Flags::user_rx()
};
mmu::map(user_pt, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(page_va),
pa: types::address::PhysicalAddress::from_raw(page),
pages: 1,
flags,
});
}
}
// Stack: 4 pages below USER_VA_BASE
for i in 0..4usize {
let sp = mmu::allocator::alloc_zeroed_page();
mmu::map(user_pt, mmu::Mapping {
va: types::address::VirtualAddress::from_raw(USER_VA_BASE - (4 - i) * 4096),
pa: types::address::PhysicalAddress::from_raw(sp),
pages: 1,
flags: mmu::Sv39Flags::user_rw(),
});
}
kernel_ref().platform_mut().set_page_table(pid, user_pt as *const mmu::PageTable as usize);
elf_info.entry_point
}
fn setup_thread(tid: ThreadId, entry: usize) {
if let Some(ctx) = kernel_ref().thread_context_mut(tid) {
ctx.set_pc(entry);
ctx.registers_mut()[2] = USER_VA_BASE;
ctx.set_status(1 << 5);
}
}
fn enter_userspace(pid: ProcessId, entry: usize, a0: usize) -> ! {
let kern = kernel_ref();
let pt_addr = kern.platform_mut().page_table_for(pid);
if pt_addr != 0 {
mmu::activate(unsafe { &*(pt_addr as *const mmu::PageTable) });
}
let kernel_sp: usize;
unsafe { core::arch::asm!("mv {0}, sp", out(reg) kernel_sp) };
trap::set_kernel_stack(kernel_sp);
unsafe {
core::arch::asm!(
"csrc sstatus, {spp}",
"csrs sstatus, {spie}",
"csrw sepc, {entry}",
"mv sp, {stack}",
"mv a0, {arg}",
"sret",
spp = in(reg) 1usize << 8,
spie = in(reg) 1usize << 5,
entry = in(reg) entry,
stack = in(reg) USER_VA_BASE,
arg = in(reg) a0,
options(noreturn),
);
}
}
fn halt(uart: &Uart, msg: &str) -> ! {
pub fn halt(uart: &Uart, msg: &str) -> ! {
uart.write_str("k-os: FATAL — ");
uart.write_str(msg);
uart.put_char(b'\n');