Add correct framebuffer mapping, so Doom works again, remove unneded

code, add cooperative scheduling on syscalls determined by the
reschedule flag, make serial console automatically clear and be a single
render, make process_scancodes push to all processes, add a user-facing
framebuffer to be mapped, automatically swap buffers inside timer
interrupt, update all submodules

kernel/src/task/context.rs

@@ -0,0 +1,34 @@
+use crate::task::scheduler::{SCHEDULER, current_pid};
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+pub struct UserContext {
+    //general purpose data regs
+    pub r15: u64,
+    pub r14: u64,
+    pub r13: u64,
+    pub r12: u64,
+    pub r11: u64, // rflags
+    pub r10: u64,
+    pub r9: u64,
+    pub r8: u64,
+    pub rsi: u64,
+    pub rdi: u64,
+    pub rbp: u64,
+    pub rdx: u64,
+    pub rcx: u64, // rip
+    pub rbx: u64,
+    pub rax: u64,
+    pub rsp: u64, // user rsp
+}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn ctx_save(regs: *const UserContext) {
+    if let Some(pid) = current_pid() {
+        let mut guard = SCHEDULER.lock();
+        if let Some(process) = guard.processes.get_mut(&pid) {
+            let saved_ctx = unsafe { core::ptr::read(regs) };
+            process.saved_ctx = Some(saved_ctx);
+        }
+    }
+}