Simple bootloader. Remove riscv-pk.

kernel/Makefile

@@ -124,17 +124,7 @@ build/x86_64/os.iso: $(kernel) $(grub_cfg)
 	@rm -r build/isofiles
 
 build/riscv32/os.iso: $(kernel)
-	@cd ../riscv-pk && \
-	 mkdir -p build && \
-	 cd build && \
-	 ../configure \
-	 	--enable-logo \
-	 	--prefix=$(RISCV) \
-	 	--disable-fp-emulation \
-	 	--host=riscv32-unknown-elf \
-	 	--with-payload=$(abspath $(kernel)) && \
-	 make && \
-	 cp bbl ../../kernel/$@
+	@cp $(kernel) $@
 
 $(kernel): kernel $(assembly_object_files) $(linker_script)
 	@$(ld) -n --gc-sections -T $(linker_script) -o $(kernel) \

kernel/src/arch/riscv32/boot/entry.asm

@@ -1,8 +1,21 @@
     .section .entry
-    .globl kern_entry
-kern_entry:
+    .global _start
+_start:
+	csrw mie, 0
+	csrw mip, 0
+    csrw mscratch, 0
+	csrw satp, 0
+	li t0, -1
+	csrw medeleg, t0
+	csrw mideleg, t0
+	csrw mcounteren, t0
+	csrw scounteren, t0
+    li t0, 1 << 11      ; MPP = S
+    csrw mstatus, t0
+    la t0, rust_main
+    csrw mepc, t0
     la sp, bootstacktop
-    tail rust_main
+	mret
 
     .section .bss
     .align 12  #PGSHIFT

kernel/src/arch/riscv32/boot/linker.ld

@@ -4,9 +4,9 @@
    See the GNU ld 'info' manual ("info ld") to learn the syntax. */
 
 OUTPUT_ARCH(riscv)
-ENTRY(kern_entry)
+ENTRY(_start)
 
-BASE_ADDRESS = 0x80020000;  /* equal to payload address in bbl */
+BASE_ADDRESS = 0x80000000;
 
 SECTIONS
 {

kernel/src/arch/riscv32/io.rs

@@ -1,5 +1,5 @@
-use super::bbl::sbi;
 use core::fmt::{Write, Result, Arguments};
+use core::ptr::{read_volatile, write_volatile};
 
 struct SerialPort;
 
@@ -7,24 +7,39 @@ impl Write for SerialPort {
     fn write_str(&mut self, s: &str) -> Result {
         for c in s.bytes() {
             if c == 127 {
-                sbi::console_putchar(8);
-                sbi::console_putchar(' ' as usize);
-                sbi::console_putchar(8);
+                putchar(8);
+                putchar(b' ');
+                putchar(8);
             } else {
-                sbi::console_putchar(c as usize);
+                putchar(c as u8);
             }
         }
         Ok(())
     }
 }
 
+fn putchar(c: u8) {
+    unsafe {
+        while read_volatile(STATUS) & CAN_WRITE == 0 {}
+        write_volatile(DATA, c as u8);
+    }
+}
+
 pub fn getchar() -> char {
-    match sbi::console_getchar() as u8 {
+    unsafe {
+        while read_volatile(STATUS) & CAN_READ == 0 {}
+        match read_volatile(DATA) {
             255 => '\0',   // null
             c => c as char,
         }
     }
+}
 
 pub fn putfmt(fmt: Arguments) {
     SerialPort.write_fmt(fmt).unwrap();
 }
+
+const DATA: *mut u8 = 0x10000000 as *mut u8;
+const STATUS: *const u8 = 0x10000005 as *const u8;
+const CAN_READ: u8 = 1 << 1;
+const CAN_WRITE: u8 = 1 << 5;

kernel/src/arch/riscv32/memory.rs

@@ -41,6 +41,7 @@ fn remap_the_kernel() {
     };
     static mut SPACE: [u8; 0x1000] = [0; 0x1000];
     let mut ms = unsafe { MemorySet::new_from_raw_space(&mut SPACE, kstack) };
+    ms.push(MemoryArea::new_identity(0x10000000, 0x10000008, MemoryAttr::default(), "serial"));
     ms.push(MemoryArea::new_identity(stext as usize, etext as usize, MemoryAttr::default().execute().readonly(), "text"));
     ms.push(MemoryArea::new_identity(sdata as usize, edata as usize, MemoryAttr::default(), "data"));
     ms.push(MemoryArea::new_identity(srodata as usize, erodata as usize, MemoryAttr::default().readonly(), "rodata"));

kernel/src/arch/riscv32/mod.rs

@@ -1,4 +1,3 @@
-extern crate bbl;
 extern crate riscv;
 
 pub mod io;

kernel/src/arch/riscv32/paging.rs

@@ -17,6 +17,7 @@ pub fn setup_page_table(frame: Frame) {
     p2.set_recursive(RECURSIVE_PAGE_PML4, frame.clone());
 
     // Set kernel identity map
+    p2[0x40].set(Frame::of_addr(PhysAddr::new(0x10000000)), EF::VALID | EF::READABLE | EF::WRITABLE);
     p2[KERNEL_PML4].set(Frame::of_addr(PhysAddr::new((KERNEL_PML4 as u32) << 22)), EF::VALID | EF::READABLE | EF::WRITABLE | EF::EXECUTABLE);
     p2[KERNEL_PML4 + 1].set(Frame::of_addr(PhysAddr::new((KERNEL_PML4 as u32 + 1) << 22)), EF::VALID | EF::READABLE | EF::WRITABLE | EF::EXECUTABLE);
 
@@ -218,10 +219,12 @@ impl InactivePageTable for InactivePageTable0 {
 impl InactivePageTable0 {
     fn map_kernel(&mut self) {
         let table = unsafe { &mut *ROOT_PAGE_TABLE };
+        let e0 = table[0x40];
         let e1 = table[KERNEL_PML4];
         assert!(!e1.is_unused());
 
         self.edit(|_| {
+            table[0x40] = e0;
             table[KERNEL_PML4].set(e1.frame(), EF::VALID | EF::GLOBAL);
         });
     }

kernel/src/arch/riscv32/timer.rs

@@ -1,5 +1,4 @@
 use super::riscv::register::*;
-use super::bbl::sbi;
 
 #[cfg(target_pointer_width = "64")]
 pub fn get_cycle() -> u64 {
@@ -29,5 +28,12 @@ pub fn init() {
 pub fn set_next() {
     // 100Hz @ QEMU
     let timebase = 100000;
-    sbi::set_timer(get_cycle() + timebase);
+    set_timer(get_cycle() + timebase);
+}
+
+fn set_timer(t: u64) {
+    unsafe {
+        asm!("csrw 0x321, $0; csrw 0x322, $1"
+        : : "r"(t as u32), "r"((t >> 32) as u32) : : "volatile");
+    }
 }