From 7797ae7810c7a107c953edc7358b803b45722074 Mon Sep 17 00:00:00 2001
From: hheik <4469778+hheik@users.noreply.github.com>
Date: Fri, 3 May 2024 13:22:00 +0300
Subject: [PATCH 1/2] Replaced main.c

---
 Makefile             |  1 -
 kernel/main.c        | 43 --------------------------------
 theseus/src/kmain.rs | 58 ++++++++++++++++++++++++++++++++++++++++++++
 theseus/src/lib.rs   |  1 +
 theseus/src/riscv.rs |  6 +++++
 theseus/src/start.rs |  6 ++---
 6 files changed, 67 insertions(+), 48 deletions(-)
 delete mode 100644 kernel/main.c
 create mode 100644 theseus/src/kmain.rs

diff --git a/Makefile b/Makefile
index 9715e5b..de1e684 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,6 @@ OBJS = \
   $K/kalloc.o \
   $K/spinlock.o \
   $K/string.o \
-  $K/main.o \
   $K/vm.o \
   $K/proc.o \
   $K/swtch.o \
diff --git a/kernel/main.c b/kernel/main.c
deleted file mode 100644
index cab0e2a..0000000
--- a/kernel/main.c
+++ /dev/null
@@ -1,43 +0,0 @@
-#include "types.h"
-#include "param.h"
-#include "memlayout.h"
-#include "riscv.h"
-#include "defs.h"
-
-volatile static int started = 0;
-
-// start() jumps here in supervisor mode on all CPUs.
-void main() {
-	if (cpuid() == 0) {
-		consoleinit();
-		printfinit();
-		printf("\n");
-		printf("xv6 kernel is booting\n");
-		printf("\n");
-		kinit();			// physical page allocator
-		kvminit();			// create kernel page table
-		kvminithart();		// turn on paging
-		procinit();			// process table
-		trapinit();			// trap vectors
-		trapinithart();		// install kernel trap vector
-		plicinit();			// set up interrupt controller
-		plicinithart();		// ask PLIC for device interrupts
-		binit();			// buffer cache
-		iinit();			// inode table
-		fileinit();			// file table
-		virtio_disk_init(); // emulated hard disk
-		userinit();			// first user process
-		__sync_synchronize();
-		started = 1;
-	} else {
-		while (started == 0)
-			;
-		__sync_synchronize();
-		printf("hart %d starting\n", cpuid());
-		kvminithart();	// turn on paging
-		trapinithart(); // install kernel trap vector
-		plicinithart(); // ask PLIC for device interrupts
-	}
-
-	scheduler();
-}
diff --git a/theseus/src/kmain.rs b/theseus/src/kmain.rs
new file mode 100644
index 0000000..583b4c2
--- /dev/null
+++ b/theseus/src/kmain.rs
@@ -0,0 +1,58 @@
+use crate::riscv;
+
+extern "C" {
+	fn cpuid() -> u64;
+	fn consoleinit();
+	fn printfinit();
+	// fn printf();
+	fn kinit();
+	fn kvminit();
+	fn kvminithart();
+	fn procinit();
+	fn trapinit();
+	fn trapinithart();
+	fn plicinit();
+	fn plicinithart();
+	fn binit();
+	fn iinit();
+	fn fileinit();
+	fn virtio_disk_init();
+	fn userinit();
+	fn scheduler();
+}
+
+pub static mut started: bool = false;
+
+pub unsafe fn kmain() {
+	if cpuid() == 0 {
+		consoleinit();
+		printfinit();
+		// printf("\n");
+		// printf("xv6 kernel is booting\n");
+		// printf("\n");
+		kinit(); // physical page allocator
+		kvminit(); // create kernel page table
+		kvminithart(); // turn on paging
+		procinit(); // process table
+		trapinit(); // trap vectors
+		trapinithart(); // install kernel trap vector
+		plicinit(); // set up interrupt controller
+		plicinithart(); // ask PLIC for device interrupts
+		binit(); // buffer cache
+		iinit(); // inode table
+		fileinit(); // file table
+		virtio_disk_init(); // emulated hard disk
+		userinit(); // first user process
+		riscv::barrier();
+		started = true;
+	} else {
+		while !started {}
+		riscv::barrier();
+		// printf("hart %d starting\n", cpuid());
+		kvminithart(); // turn on paging
+		trapinithart(); // install kernel trap vector
+		plicinithart(); // ask PLIC for device interrupts
+	}
+
+	scheduler();
+}
diff --git a/theseus/src/lib.rs b/theseus/src/lib.rs
index 59c5e02..359c7a4 100644
--- a/theseus/src/lib.rs
+++ b/theseus/src/lib.rs
@@ -1,6 +1,7 @@
 #![no_std]
 #![crate_type = "staticlib"]
 
+pub mod kmain;
 pub mod memlayout;
 pub mod param;
 pub mod riscv;
diff --git a/theseus/src/riscv.rs b/theseus/src/riscv.rs
index 94994d2..de6377c 100644
--- a/theseus/src/riscv.rs
+++ b/theseus/src/riscv.rs
@@ -327,3 +327,9 @@ pub fn PX(level: u64, va: u64) -> u64 {
 // Sv39, to avoid having to sign-extend virtual addresses
 // that have the high bit set.
 pub const MAXVA: u64 = 1 << (9 + 9 + 9 + 12 - 1);
+
+/// Hardware memory barrier
+#[inline]
+pub unsafe fn barrier() {
+	asm!("fence")
+}
diff --git a/theseus/src/start.rs b/theseus/src/start.rs
index 9f095d6..4cb49c1 100644
--- a/theseus/src/start.rs
+++ b/theseus/src/start.rs
@@ -1,6 +1,7 @@
 use core::arch::asm;
 use core::usize;
 
+use crate::kmain::kmain;
 use crate::memlayout::{CLINT_MTIME, CLINT_MTIMECMP};
 use crate::param::NCPU;
 use crate::riscv as rv;
@@ -8,9 +9,6 @@ use crate::riscv as rv;
 extern "C" {
 	// assembly code in kernelvec.S for machine-mode timer interrupt.
 	fn timervec();
-
-	// main.c
-	fn main();
 }
 
 #[repr(align(16))]
@@ -34,7 +32,7 @@ pub unsafe extern "C" fn start() {
 
 	// set M Exception Program Counter to main, for mret.
 	// requires gcc -mcmodel=medany
-	rv::w_mepc(main as *const () as u64);
+	rv::w_mepc(kmain as *const () as u64);
 
 	// disable paging for now.
 	rv::w_satp(0);

From 623c44fcb34a2fd3fe15e4e237e79ea2cbf0dd7c Mon Sep 17 00:00:00 2001
From: hheik <4469778+hheik@users.noreply.github.com>
Date: Mon, 6 May 2024 02:25:45 +0300
Subject: [PATCH 2/2] Fixed spinlock halting caused by data misalignment

---
 kernel/spinlock.c       |  6 ------
 theseus/src/spinlock.rs | 13 +++++++++++--
 theseus/src/uart.rs     | 14 ++++++++------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index aaf1b09..51252cf 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -8,12 +8,6 @@
 #include "proc.h"
 #include "defs.h"
 
-void initlock(struct spinlock *lk, char *name) {
-	lk->name = name;
-	lk->locked = 0;
-	lk->cpu = 0;
-}
-
 // Acquire the lock.
 // Loops (spins) until the lock is acquired.
 void acquire(struct spinlock *lk) {
diff --git a/theseus/src/spinlock.rs b/theseus/src/spinlock.rs
index faeafd0..cfc6ac7 100644
--- a/theseus/src/spinlock.rs
+++ b/theseus/src/spinlock.rs
@@ -1,9 +1,18 @@
+use core::ptr::null_mut;
+
 // Mutual exclusion lock.
 #[repr(C)]
 pub struct SpinLock {
 	// Is the lock held?
 	pub locked: u32, // C boolean
 	// For debugging:
-	pub name: Option<*mut ()>, // Name of lock.
-	pub cpu: Option<*mut ()>,  // The cpu holding the lock.
+	pub name: *const u8, // Name of lock.
+	pub cpu: *mut (),    // The cpu holding the lock.
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn initlock(lock: *mut SpinLock, name: *const u8) {
+	(*lock).name = name;
+	(*lock).locked = 0;
+	(*lock).cpu = null_mut();
 }
diff --git a/theseus/src/uart.rs b/theseus/src/uart.rs
index 1957f08..1fcbf26 100644
--- a/theseus/src/uart.rs
+++ b/theseus/src/uart.rs
@@ -1,11 +1,13 @@
-use crate::{memlayout::UART0, spinlock::SpinLock};
-use core::ptr::addr_of_mut;
+use crate::{
+	memlayout::UART0,
+	spinlock::{initlock, SpinLock},
+};
+use core::ptr::{addr_of_mut, null, null_mut};
 
 extern "C" {
 	// spinlock.c
 	fn push_off();
 	fn pop_off();
-	fn initlock(spinlock: *mut SpinLock, name: *const u8);
 	fn acquire(spinlock: *mut SpinLock);
 	fn release(spinlock: *mut SpinLock);
 
@@ -60,12 +62,12 @@ pub fn WriteReg(reg: u8, v: u8) {
 // the transmit output buffer.
 static mut uart_tx_lock: crate::spinlock::SpinLock = crate::spinlock::SpinLock {
 	locked: 0,
-	cpu: None,
-	name: None,
+	cpu: null_mut(),
+	name: null(),
 };
 
 // NOTE: string 'uart\0' for c-implmentation of spinlock. Stupid but works.
-static UART_LOCK_NAME: [u8; 5] = [117, 97, 114, 116, 0];
+static UART_LOCK_NAME: [u8; 5] = [0x75, 0x61, 0x72, 0x74, 0];
 
 const UART_TX_BUF_SIZE: usize = 32;
 static mut uart_tx_buf: [u8; UART_TX_BUF_SIZE] = [0; UART_TX_BUF_SIZE];