std: create a heap for user programs automatically!

This completes our journey to having user programs looking almost completely
normal! I am pretty amazed that this hack works so successfully, but not
complaining.

Lots of work still to do in terms of making Poplar primitives nicer to work
with, but this is a good start!

lib/std/Cargo.toml

@@ -5,3 +5,5 @@ authors = ["Isaac Woods"]
 edition = "2021"
 
 [dependencies]
+poplar = { path = "../poplar" }
+linked_list_allocator = "0.10.5"

lib/std/src/lib.rs

@@ -5,6 +5,7 @@
 extern crate alloc;
 
 use core::panic::PanicInfo;
+use linked_list_allocator::LockedHeap;
 
 /*
  * Public re-exports. Most of this is copied from real `std`, plus our `poplar` library.
@@ -65,16 +66,31 @@ pub mod prelude {
     }
 }
 
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();
+
 #[no_mangle]
 unsafe extern "C" fn _start() -> ! {
     extern "C" {
         fn main(argc: isize, argv: *const *const u8) -> isize;
     }
 
+    // Initialize the heap
+    const HEAP_START: usize = 0x600000000;
+    const HEAP_SIZE: usize = 0x4000;
+    let heap_memory_object =
+        poplar::syscall::create_memory_object(HEAP_START, HEAP_SIZE, true, false, 0x0 as *mut usize).unwrap();
+    unsafe {
+        poplar::syscall::map_memory_object(&heap_memory_object, &poplar::ZERO_HANDLE, None, 0x0 as *mut usize)
+            .unwrap();
+        ALLOCATOR.lock().init(HEAP_START as *mut u8, HEAP_SIZE);
+    }
+
     main(0, core::ptr::null());
 
+    poplar::syscall::early_log("Returned from main. Looping.").unwrap();
     loop {
-        // TODO: yield here idk
+        poplar::syscall::yield_to_kernel();
         // TODO: actually this should call an exit system call or something
     }
 }
@@ -88,5 +104,6 @@ fn lang_start<T>(main: fn() -> T, _argc: isize, _argv: *const *const u8, _sigpip
 #[panic_handler]
 pub fn handle_panic(info: &PanicInfo) -> ! {
     // TODO: print a panic message
+    let _ = poplar::syscall::early_log("Panicked!");
     loop {}
 }

user/simple_fb/Cargo.toml

@@ -6,8 +6,6 @@ edition = "2021"
 
 [dependencies]
 std = { path = "../../lib/std" }
-poplar = { path = "../../lib/poplar", features = ["can_alloc"] }
-linked_list_allocator = "0.10.2"
 log = "0.4"
 gfxconsole = { path = "../../lib/gfxconsole" }
 ptah = { path = "../../lib/ptah" }

user/simple_fb/src/main.rs

@@ -1,43 +1,23 @@
-extern crate alloc;
-
-use alloc::{
-    format,
-    string::{String, ToString},
-    vec::Vec,
-};
-use core::mem::MaybeUninit;
 use gfxconsole::{Bgr32, Format, Framebuffer, Pixel};
-use linked_list_allocator::LockedHeap;
 use log::info;
-use poplar::{
-    caps::{CapabilitiesRepr, CAP_EARLY_LOGGING, CAP_GET_FRAMEBUFFER, CAP_PADDING, CAP_SERVICE_USER},
-    channel::Channel,
-    early_logger::EarlyLogger,
-    syscall::{self, FramebufferInfo, PixelFormat},
-};
 use ptah::{Deserialize, Serialize};
+use std::{
+    mem::MaybeUninit,
+    poplar::{
+        caps::{CapabilitiesRepr, CAP_EARLY_LOGGING, CAP_GET_FRAMEBUFFER, CAP_PADDING, CAP_SERVICE_USER},
+        channel::Channel,
+        early_logger::EarlyLogger,
+        syscall::{self, FramebufferInfo, PixelFormat},
+    },
+};
 
 #[derive(Debug, Serialize, Deserialize)]
 struct TestMessage {
     id: usize,
     message: String,
 }
 
-#[global_allocator]
-static ALLOCATOR: LockedHeap = LockedHeap::empty();
-
 pub fn main() {
-    syscall::early_log("Hello from FB").unwrap();
-    // Initialise the heap
-    const HEAP_START: usize = 0x600000000;
-    const HEAP_SIZE: usize = 0x4000;
-    let heap_memory_object =
-        syscall::create_memory_object(HEAP_START, HEAP_SIZE, true, false, 0x0 as *mut usize).unwrap();
-    unsafe {
-        syscall::map_memory_object(&heap_memory_object, &poplar::ZERO_HANDLE, None, 0x0 as *mut usize).unwrap();
-        ALLOCATOR.lock().init(HEAP_START as *mut u8, HEAP_SIZE);
-    }
-
     log::set_logger(&EarlyLogger).unwrap();
     log::set_max_level(log::LevelFilter::Trace);
     info!("Simple framebuffer driver is running!");
@@ -96,7 +76,7 @@ fn make_framebuffer() -> Framebuffer<Bgr32> {
     unsafe {
         syscall::map_memory_object(
             &framebuffer_handle,
-            &poplar::ZERO_HANDLE,
+            &std::poplar::ZERO_HANDLE,
             Some(FRAMEBUFFER_ADDRESS),
             0x0 as *mut _,
         )