Modify linker script to mipsel arch, add dts in kernel binary

Signed-off-by: Harry Chen <i@harrychen.xyz>

kernel/Makefile

@@ -42,18 +42,24 @@ build_path := target/$(target)/$(mode)
 kernel := $(build_path)/rcore
 kernel_img := $(build_path)/kernel.img
 bootimage := $(build_path)/bootimage.bin
+dtb := src/arch/$(arch)/boot/dts/$(board).dtb
 bootloader_dir = ../bootloader
 bootloader := $(bootloader_dir)/target/$(target)/$(mode)/rcore-bootloader
 bbl_path := $(PWD)/../riscv-pk
 user_dir := ../user
 
+ifeq ($(arch), aarch64)
+board := raspi3
+
+ifeq ($(arch), mipsel)
+board := malta
+
 ### export environments ###
 export ARCH = $(arch)
 export BOARD = $(board)
 export SMP = $(smp)
+export DTB = $(dtb)
 export SFSIMG = $(user_dir)/build/$(arch).qcow2
-ifeq ($(arch), aarch64)
-board := raspi3
 export SFSIMG = $(user_dir)/build/$(arch).img
 endif
 
@@ -104,6 +110,13 @@ qemu_opts += \
 	-kernel $(kernel_img)
 endif
 
+else ifeq ($(arch), mipsel)
+qemu_opts += \
+	-machine $(board) \
+	-serial null -serial mon:stdio \
+	-kernel $(kernel_img)
+endif
+
 ifdef d
 qemu_opts += -d $(d)
 endif
@@ -171,9 +184,10 @@ cc := $(prefix)gcc
 as := $(prefix)as
 gdb := $(prefix)gdb
 strip := $(prefix)strip
+dtc := dtc
 export CC = $(cc)
 
-.PHONY: all clean build asm doc  debug kernel sfsimg install run justrun runnet justrunnet runui justrunui runtest justruntest
+.PHONY: all clean build asm doc debug kernel sfsimg install run justrun runnet justrunnet runui justrunui runtest justruntest
 
 all: kernel
 
@@ -220,8 +234,18 @@ header:
 sym:
 	@$(objdump) -t $(kernel) | less
 
+### device tree process ###
+
+%.dtb: %.dts
+	$(dtc) -I dts -O dtb -o $@ $<
+
+### bootloader and kernel image ###
+
 $(bootloader): $(kernel)
 ifeq ($(arch), aarch64)
+	need_bootloader := true
+endif
+ifeq ($(need_bootloader), true)
 	@echo Building $(arch) bootloader
 	@$(strip) $(kernel) -o $(kernel)_stripped
 	@cd $(bootloader_dir) && make arch=$(arch) mode=$(mode) payload=../kernel/$(kernel)_stripped
@@ -254,11 +278,12 @@ else ifeq ($(arch), riscv64)
 else ifeq ($(arch), aarch64)
 	@$(objcopy) $(bootloader) --strip-all -O binary $@
 else ifeq ($(arch), mipsel)
-	# TODO write mipsel bootloader
-	false
+	# qemu-system-mipsel accepts ELF file only, so don't use objcopy
+	@cp $(kernel) $(kernel)_orig
+	@$(strip) $(kernel) -o $(kernel)
 endif
 
-kernel:
+kernel: $(dtb)
 	@echo Building $(arch) kernel
 ifeq ($(arch), x86_64)
 	@bootimage build $(build_args)

kernel/build.rs

@@ -19,6 +19,7 @@ fn main() {
 		"riscv64" => {
 		}
 		"mipsel" => {
+			gen_dtb_asm().unwrap();
 		}
 		"aarch64" => {
 		}
@@ -49,3 +50,32 @@ fn gen_vector_asm() -> Result<()> {
 	}
 	Ok(())
 }
+
+
+fn gen_dtb_asm() -> Result<()> {
+	let arch = std::env::var("ARCH").unwrap();
+    let dtb = std::env::var("DTB").unwrap();
+	let board = std::env::var("BOARD").unwrap();
+
+    if !Path::new(&dtb).is_file() {
+        panic!("DTB `{}` not found", dtb)
+    }
+
+	let mut f = File::create(format!("src/arch/{}/boot/dtb.S", arch)).unwrap();
+
+    println!("cargo:rerun-if-changed={}", dtb);
+    println!("cargo:rerun-if-env-changed=DTB");
+
+	writeln!(f, "# generated by build.rs - do not edit")?;
+	writeln!(f, ".intel_syntax noprefix")?;
+	write!(f, r#"
+    .section .dtb,"a"
+    .align 12
+    .global _dtb_start, _dtb_end
+_dtb_start:
+    .incbin "{}"
+_dtb_end:
+    "#, dtb)?;
+
+    Ok(())
+}

kernel/src/arch/mipsel/board/u540/linker.ld

@@ -1,49 +0,0 @@
-/* Copy from bbl-ucore : https://ring00.github.io/bbl-ucore      */
-
-/* Simple linker script for the ucore kernel.
-   See the GNU ld 'info' manual ("info ld") to learn the syntax. */
-
-OUTPUT_ARCH(riscv)
-ENTRY(_start)
-
-BASE_ADDRESS = 0xffffffffc0020000;
-
-SECTIONS
-{
-    /* Load the kernel at this address: "." means the current address */
-    . = BASE_ADDRESS;
-    start = .;
-
-    .text : {
-        stext = .;
-        *(.text.entry)
-        *(.text .text.*)
-        . = ALIGN(4K);
-        etext = .;
-    }
-
-    .rodata : {
-        srodata = .;
-        *(.rodata .rodata.*)
-        . = ALIGN(4K);
-        erodata = .;
-    }
-
-    .data : {
-        sdata = .;
-        *(.data .data.*)
-        edata = .;
-    }
-
-    .stack : {
-        *(.bss.stack)
-    }
-
-    .bss : {
-        sbss = .;
-        *(.bss .bss.*)
-        ebss = .;
-    }
-
-    PROVIDE(end = .);
-}

kernel/src/arch/mipsel/board/u540/mod.rs

@@ -1,18 +0,0 @@
-use super::consts::KERNEL_OFFSET;
-
-/// Mask all external interrupt except serial.
-pub unsafe fn init_external_interrupt() {
-    const HART1_S_MODE_INTERRUPT_ENABLES: *mut u64 = (KERNEL_OFFSET + 0x0C00_2100) as *mut u64;
-    const SERIAL: u64 = 4;
-    HART1_S_MODE_INTERRUPT_ENABLES.write(1 << SERIAL);
-}
-
-/// Claim and complete external interrupt by reading and writing to
-/// PLIC Interrupt Claim/Complete Register.
-pub unsafe fn handle_external_interrupt() {
-    const HART1_S_MODE_INTERRUPT_CLAIM_COMPLETE: *mut u32 = (KERNEL_OFFSET + 0x0C20_2004) as *mut u32;
-    // claim
-    let source = HART1_S_MODE_INTERRUPT_CLAIM_COMPLETE.read();
-    // complete
-    HART1_S_MODE_INTERRUPT_CLAIM_COMPLETE.write(source);
-}

kernel/src/arch/mipsel/boot/entry.S

@@ -3,8 +3,10 @@
 	.set noreorder
     .section .text.entry
     .globl _start
+
 _start:
 	la sp, bootstacktop
+    la gp, _gp
 
     b rust_main
 	nop

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

@@ -1,21 +1,14 @@
-/* Copy from bbl-ucore : https://ring00.github.io/bbl-ucore      */
-
 /* Simple linker script for the ucore kernel.
    See the GNU ld 'info' manual ("info ld") to learn the syntax. */
 
 OUTPUT_ARCH(riscv)
 ENTRY(_start)
 
-BASE_ADDRESS = 0xC0020000;
+BASE_ADDRESS = 0x80100000;
 
 SECTIONS
 {
-    . = 0xC0000000;
-    .boot : {
-        KEEP(*(.text.boot))
-    }
 
-    /* Load the kernel at this address: "." means the current address */
     . = BASE_ADDRESS;
     start = .;
 
@@ -30,6 +23,7 @@ SECTIONS
     .rodata : {
         srodata = .;
         *(.rodata .rodata.*)
+        *(.dtb)
         . = ALIGN(4K);
         erodata = .;
     }

kernel/src/arch/mipsel/boot/linker64.ld

@@ -1,49 +0,0 @@
-/* Copy from bbl-ucore : https://ring00.github.io/bbl-ucore      */
-
-/* Simple linker script for the ucore kernel.
-   See the GNU ld 'info' manual ("info ld") to learn the syntax. */
-
-OUTPUT_ARCH(riscv)
-ENTRY(_start)
-
-BASE_ADDRESS = 0xffffffffc0020000;
-
-SECTIONS
-{
-    /* Load the kernel at this address: "." means the current address */
-    . = BASE_ADDRESS;
-    start = .;
-
-    .text : {
-        stext = .;
-        *(.text.entry)
-        *(.text .text.*)
-        . = ALIGN(4K);
-        etext = .;
-    }
-
-    .rodata : {
-        srodata = .;
-        *(.rodata .rodata.*)
-        . = ALIGN(4K);
-        erodata = .;
-    }
-
-    .data : {
-        sdata = .;
-        *(.data .data.*)
-        edata = .;
-    }
-
-    .stack : {
-        *(.bss.stack)
-    }
-
-    .bss : {
-        sbss = .;
-        *(.bss .bss.*)
-        ebss = .;
-    }
-
-    PROVIDE(end = .);
-}

kernel/src/arch/mipsel/consts.rs

@@ -1,40 +1,16 @@
 // Physical address available on THINPAD:
 // [0x80000000, 0x80800000]
-#[cfg(target_arch = "riscv32")]
-pub const RECURSIVE_INDEX: usize = 0x3fd;
-#[cfg(target_arch = "riscv64")]
-pub const RECURSIVE_INDEX: usize = 0o774;
-// Under riscv64, upon booting, paging is enabled by bbl and
-//  root_table[0777] maps to p3_table,
-//   and p3_table[0777] maps to gigapage 8000_0000H,
-//   so 0xFFFF_FFFF_8000_0000 maps to 0x8000_0000
-//  root_table[0774] points to root_table itself as page table
-//  root_table[0775] points to root_table itself as leaf page
-//  root_table[0776] points to a temp page table as leaf page
 
-#[cfg(target_arch = "riscv32")]
 pub const KERNEL_OFFSET: usize = 0xC000_0000;
-#[cfg(target_arch = "riscv64")]
-pub const KERNEL_OFFSET: usize = 0xFFFF_FFFF_C000_0000;
 
 #[cfg(target_arch = "riscv32")]
 pub const KERNEL_P2_INDEX: usize = (KERNEL_OFFSET >> 12 >> 10) & 0x3ff;
-#[cfg(target_arch = "riscv64")]
-pub const KERNEL_P4_INDEX: usize = (KERNEL_OFFSET >> 12 >> 9 >> 9 >> 9) & 0o777;
 
 pub const KERNEL_HEAP_SIZE: usize = 0x00a0_0000;
 
-#[cfg(target_arch = "riscv32")]
-pub const MEMORY_OFFSET: usize = 0x8000_0000;
-#[cfg(target_arch = "riscv64")]
 pub const MEMORY_OFFSET: usize = 0x8000_0000;
-
-#[cfg(target_arch = "riscv32")]
-pub const MEMORY_END: usize = 0x8100_0000;
-#[cfg(target_arch = "riscv64")]
 pub const MEMORY_END: usize = 0x8100_0000;
 
-// FIXME: rv64 `sh` and `ls` will crash if stack top > 0x80000000 ???
 pub const USER_STACK_OFFSET: usize = 0x80000000 - USER_STACK_SIZE;
 pub const USER_STACK_SIZE: usize = 0x10000;
 pub const USER32_STACK_OFFSET: usize = 0xC0000000 - USER_STACK_SIZE;

kernel/src/arch/mipsel/mod.rs

@@ -8,41 +8,48 @@ pub mod consts;
 pub mod cpu;
 pub mod syscall;
 pub mod rand;
-#[cfg(feature = "board_u540")]
-#[path = "board/u540/mod.rs"]
-mod board;
 
 use log::*;
+use mips::registers;
+use mips::instructions;
+
+extern "C" {
+    fn _dtb_start();
+    fn _dtb_end();
+}
 
 #[no_mangle]
-pub extern fn rust_main(hartid: usize, dtb: usize, hart_mask: usize) -> ! {
-    // An initial recursive page table has been set by BBL (shared by all cores)
+pub extern fn rust_main() -> ! {
+
+    // unsafe { cpu::set_cpu_id(hartid); }
 
-    unsafe { cpu::set_cpu_id(hartid); }
+    let ebase = cp0::ebase::read_u32();
+    let cpu_id = ebase & 0x3ff;
+    let dtb_start = _dtb_start as usize;
+    let dtb_end = _dtb_end as usize;
 
-    if hartid != BOOT_HART_ID {
-        while unsafe { !cpu::has_started(hartid) }  { }
-        println!("Hello RISCV! in hart {}, dtb @ {:#x}", hartid, dtb);
-        others_main();
-        //other_main -> !
+    if cpu_id != BOOT_CPU_ID {
+        // TODO: run others_main on other CPU
+        // while unsafe { !cpu::has_started(hartid) }  { }
+        // println!("Hello RISCV! in hart {}, dtb @ {:#x}", hartid, dtb);
+        // others_main();
+        loop {}
     }
 
     unsafe { memory::clear_bss(); }
 
-    println!("Hello RISCV! in hart {}, dtb @ {:#x}", hartid, dtb);
+    println!("Hello MIPS 32 from CPU {}, dtb @ {:#x}", cpu_id, dtb_start);
 
     crate::logging::init();
     interrupt::init();
     memory::init(dtb);
     timer::init();
-    // FIXME: init driver on u540
-    #[cfg(not(feature = "board_u540"))]
-    crate::drivers::init(dtb);
-    #[cfg(feature = "board_u540")]
-    unsafe { board::init_external_interrupt(); }
+    // TODO: initialize device with dtb
+    // crate::drivers::init(dtb);
     crate::process::init();
 
-    unsafe { cpu::start_others(hart_mask); }
+    // TODO: start other CPU
+    // unsafe { cpu::start_others(hart_mask); }
     crate::kmain();
 }
 
@@ -53,35 +60,8 @@ fn others_main() -> ! {
     crate::kmain();
 }
 
-#[cfg(not(feature = "board_u540"))]
-const BOOT_HART_ID: usize = 0;
-#[cfg(feature = "board_u540")]
-const BOOT_HART_ID: usize = 1;
-
-/// Constant & Macro for `trap.asm`
-#[cfg(target_arch = "riscv32")]
-global_asm!(r"
-    .equ XLENB,     4
-    .equ XLENb,     32
-    .macro LOAD a1, a2
-        lw \a1, \a2*XLENB(sp)
-    .endm
-    .macro STORE a1, a2
-        sw \a1, \a2*XLENB(sp)
-    .endm
-");
-#[cfg(target_arch = "riscv64")]
-global_asm!(r"
-    .equ XLENB,     8
-    .equ XLENb,     64
-    .macro LOAD a1, a2
-        ld \a1, \a2*XLENB(sp)
-    .endm
-    .macro STORE a1, a2
-        sd \a1, \a2*XLENB(sp)
-    .endm
-");
-
+const BOOT_CPU_ID: usize = 0;
 
 global_asm!(include_str!("boot/entry.S"));
 global_asm!(include_str!("boot/trap.S"));
+global_asm!(include_str!("boot/dtb.S"));