Add rust_payload and fixes to allow running it as supervisor

Note that the 'riscv32ima-unknown-none-elf' target is not available by
default in rustc, you need a patched version.

I'm also pretty sure just converting the ELF binary to raw using objdump
messes with stack and heap addresses, but it seems to work fine for now.

.gitignore

@@ -5,5 +5,7 @@ rvc
 *.o
 elfy/target
 elfy/Cargo.lock
+rust_payload/target
+rust_payload/Cargo.lock
 fw_payload.*
 *.dtb

Makefile

@@ -15,7 +15,8 @@ $(TARGET): $(OBJS)
 
 .PHONY: clean
 clean:
-	$(RM) $(TARGET) $(OBJS) $(DEPS)
+	$(RM) $(TARGET) $(OBJS) $(DEPS) fw_payload.*
+	$(MAKE) -C opensbi clean
 
 -include $(DEPS)
 
@@ -24,16 +25,31 @@ dts.dtb: dts.dts
 	dtc -o $@ $<
 
 OPENSBI_BUILD="opensbi/build/platform/generic/firmware"
+PAYLOAD="rust_payload/target/riscv32ima-unknown-none-elf/release/rust_payload.bin"
+
+$(PAYLOAD): $(shell find rust_payload/src -type f)
+	cd rust_payload; \
+		cargo +riscv32ima rustc -Zbuild-std --release --target "riscv32ima-unknown-none-elf" -- -Clink-arg=-Tlinker.ld -Clinker=riscv32-elf-ld
+	riscv32-elf-objcopy -O binary \
+		rust_payload/target/riscv32ima-unknown-none-elf/release/rust_payload $(PAYLOAD)
 
 fw_payload.bin: fw_payload.elf
 	cp $(OPENSBI_BUILD)/fw_payload.bin .
-fw_payload.elf: opensbi
+fw_payload.elf: $(PAYLOAD)
 	env CROSS_COMPILE=riscv64-elf- \
 		PLATFORM=generic \
 		PLATFORM_RISCV_XLEN=32 \
 		PLATFORM_RISCV_ISA=rv32ima \
 		PLATFORM_RISCV_ABI=ilp32 \
+		FW_PAYLOAD_PATH=../$(PAYLOAD) \
 		FW_PIC=n \
 		ELFFLAGS=-L/usr/lib/gcc/riscv64-elf/10.2.0/rv32im/ilp32 \
 		$(MAKE) -C opensbi all
 	cp $(OPENSBI_BUILD)/fw_payload.elf .
+
+.PHONY: run
+run: fw_payload.bin $(TARGET) dts.dtb
+	./rvc -b fw_payload.bin -d dts.dtb
+
+run-v1: fw_payload.bin $(TARGET) dts.dtb
+	./rvc -b fw_payload.bin -d dts.dtb -v1

dts.dts

@@ -4,7 +4,7 @@
     #address-cells = <0x2>;
     #size-cells = <0x2>;
     compatible = "riscv-virtio";
-    model = "riscv-virtio,qemu";
+    model = "generic,rvc";
 
     chosen {
         bootargs = "ttyS0";

rust_payload/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "rust_payload"
+version = "0.1.0"
+edition = "2018"
+
+[dependencies]
+riscv = "0.6.0"
+linked_list_allocator = "0.9.0"
+lite-json = {version="0.1.3", default-features=false}

rust_payload/linker.ld

@@ -0,0 +1,30 @@
+OUTPUT_ARCH( "riscv" )
+
+ENTRY( _start )
+
+MEMORY
+{
+  ram (rwx) : ORIGIN = 0x80400000, LENGTH = 0x800000
+}
+
+SECTIONS
+{
+  .kernel : {
+    *(.start_here)
+    *(.text .text.*)
+    *(.rodata .rodata.*)
+    *(.data .data.*)
+  } > ram
+
+  .stack (NOLOAD) : {
+    . = . + 0x20000;
+    PROVIDE(_end_stack = .);
+  } > ram
+
+  .heap (NOLOAD) : {
+    PROVIDE(_begin_heap = .);
+    . = . + 0x40000;
+    PROVIDE(_end_heap = .);
+  } > ram
+
+}

rust_payload/src/low_level/mod.rs

@@ -0,0 +1,64 @@
+use core::panic::PanicInfo;
+use linked_list_allocator::LockedHeap;
+
+mod opensbi;
+pub use opensbi::*;
+
+#[naked]
+#[no_mangle]
+#[link_section = ".start_here"]
+#[allow(dead_code)]
+/// The actual entry point of the binary, sets up stack and jumps to 'main'
+extern "C" fn _start() -> ! {
+    unsafe {
+        asm!(
+            "
+                la sp, {end_stack}
+                j main
+            ",
+            end_stack = sym _end_stack,
+            options(noreturn)
+        );
+    }
+}
+
+#[alloc_error_handler]
+fn alloc_error(_layout: core::alloc::Layout) -> ! {
+    println("ALLOC ERROR!");
+    loop {}
+}
+
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+    println("PANIC!");
+    loop {}
+}
+
+// defined by linker script
+extern "C" {
+    static _end_stack: usize;
+    static _begin_heap: usize;
+    static _end_heap: usize;
+}
+
+#[global_allocator]
+static ALLOCATOR: LockedHeap = LockedHeap::empty();
+
+pub unsafe fn init_heap() {
+    let stack_end = &_end_stack as *const usize as usize;
+    let heap_start = &_begin_heap as *const usize as usize;
+    let heap_end = &_end_heap as *const usize as usize;
+    let heap_size = heap_end - heap_start;
+
+    print("> stack_end:   ");
+    print_usize(stack_end);
+    print("\n> heap_start:  ");
+    print_usize(heap_start);
+    print("\n> heap_end:    ");
+    print_usize(heap_end);
+    print("\n> heap_size:   ");
+    print_usize(heap_size);
+    print("\n");
+
+    ALLOCATOR.lock().init(heap_start, heap_size);
+}

rust_payload/src/low_level/opensbi.rs

@@ -0,0 +1,67 @@
+pub const _SBI_SET_TIMER: usize = 0x00;
+pub const SBI_CONSOLE_PUTCHAR: usize = 0x01;
+pub const SBI_CONSOLE_GETCHAR: usize = 0x02;
+
+#[inline(always)]
+pub fn ecall(nr: usize, arg0: usize, arg1: usize, arg2: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        asm!(
+            "ecall",
+            in("x17") nr,
+            in("x10") arg0,
+            in("x11") arg1,
+            in("x12") arg2,
+            lateout("x10") ret
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn print_char(ch: u8) {
+    ecall(SBI_CONSOLE_PUTCHAR, ch as usize, 0, 0);
+}
+
+pub fn println(s: &str) {
+    print(s);
+    print_char('\n' as u8);
+}
+
+pub fn print(s: &str) {
+    s.chars().for_each(|c| print_char(c as u8));
+}
+
+#[inline(always)]
+fn print_hex_part(u: u8) {
+    match u {
+        0 => print("0"),
+        1 => print("1"),
+        2 => print("2"),
+        3 => print("3"),
+        4 => print("4"),
+        5 => print("5"),
+        6 => print("6"),
+        7 => print("7"),
+        8 => print("8"),
+        9 => print("9"),
+        10 => print("A"),
+        11 => print("B"),
+        12 => print("C"),
+        13 => print("D"),
+        14 => print("E"),
+        15 => print("F"),
+        _ => unreachable!(),
+    }
+}
+
+pub fn print_usize(u: usize) {
+    print("0x");
+    for i in 0..=3 {
+        let part = ((u >> ((3 - i) * 8)) & 0xff) as u8;
+        let l = part & 0xF;
+        let h = (part >> 4) & 0xF;
+        print_hex_part(h);
+        print_hex_part(l);
+    }
+}

rust_payload/src/main.rs

@@ -0,0 +1,117 @@
+#![no_std]
+#![no_main]
+#![feature(asm)]
+#![feature(naked_functions)]
+#![feature(alloc_error_handler)]
+
+#[macro_use]
+extern crate alloc;
+
+mod low_level;
+use low_level::*;
+
+use riscv::register;
+
+#[no_mangle]
+pub fn main() -> ! {
+    print("\n");
+
+    println("Welcome to Rust-land!");
+
+    print("Cycles before: ");
+    print_usize(register::time::read());
+    print("\n\n");
+
+    println("Initializing heap...");
+    unsafe {
+        init_heap();
+    }
+    print("\n");
+
+    // input_test();
+    // print("\n");
+
+    json_test();
+    print("\n");
+
+    print("Cycles after: ");
+    print_usize(register::time::read());
+    print("\n");
+
+    println("Tests done, entering infinite loop!");
+    loop {}
+}
+
+/// Test opensbi uart input
+fn input_test() {
+    print("Please enter some text: ");
+    let mut s = vec![];
+    loop {
+        let i = loop {
+            let i = ecall(SBI_CONSOLE_GETCHAR, 0, 0, 0);
+            if i != 0 && i != usize::MAX {
+                break i as u8 as char;
+            }
+        };
+
+        match i {
+            '\n' => break,
+            _ => s.push(i as u8)
+        }
+    }
+    print("Your text was: ");
+    for c in s {
+        print_char(c);
+    }
+    print("\n");
+}
+
+/// From lite-json docs, a simple example to showcase functionality
+fn json_test() {
+    use lite_json::json::{JsonValue, NumberValue};
+    use lite_json::Serialize;
+
+    println("Preparing JSON test...");
+
+    let mut object_elements = vec![];
+
+    let boolean_value = true;
+    let object_key = "boolean".chars().collect();
+    object_elements.push((object_key, JsonValue::Boolean(boolean_value)));
+
+    let array_value = vec![
+        JsonValue::Boolean(true),
+        JsonValue::Boolean(false),
+        JsonValue::Boolean(true),
+    ];
+    let object_key = "array".chars().collect();
+    object_elements.push((object_key, JsonValue::Array(array_value)));
+
+    let string_value = "Hello World!".chars().collect();
+    let object_key = "string".chars().collect();
+    object_elements.push((object_key, JsonValue::String(string_value)));
+
+    let number_value = NumberValue {
+        integer: 1234,
+        fraction: 0,
+        fraction_length: 0,
+        exponent: 0,
+    };
+    let object_key = "number".chars().collect();
+    object_elements.push((object_key, JsonValue::Number(number_value)));
+
+    let object_key = "null".chars().collect();
+    object_elements.push((object_key, JsonValue::Null));
+
+    let object_value = JsonValue::Object(object_elements);
+
+    println("JSON dump:");
+
+    let json = object_value.format(2);
+    for x in json {
+        print_char(x as u8);
+    }
+
+    print("\n");
+}
+

src/csr.h

@@ -38,7 +38,7 @@ const uint CSR_MTVAL = 0x343;
 const uint CSR_MIP = 0x344;
 const uint _CSR_PMPCFG0 = 0x3a0;
 const uint _CSR_PMPADDR0 = 0x3b0;
-const uint _CSR_MCYCLE = 0xb00;
+const uint CSR_MCYCLE = 0xb00;
 const uint CSR_CYCLE = 0xc00;
 const uint CSR_TIME = 0xc01;
 const uint _CSR_INSERT = 0xc02;
@@ -56,6 +56,7 @@ uint read_csr_raw(cpu_t *cpu, uint address) {
         case CSR_SIE: return cpu->csr.data[CSR_MIE] & 0x222;
         case CSR_SIP: return cpu->csr.data[CSR_MIP] & 0x222;
         case CSR_TIME: return cpu->clint.mtime_lo;
+        case CSR_MCYCLE: return cpu->clock;
         case CSR_CYCLE: return cpu->clock;
         case CSR_MHARTID: return 0;
         default: return cpu->csr.data[address & 0xffff];
@@ -122,7 +123,7 @@ void set_csr(cpu_t *cpu, uint address, uint value, ins_ret *ret) {
             if (address == CSR_SATP) {
                 // TODO: update MMU addressing mode
                 if (VERBOSE >= 1)
-                    printf("WARN: Ignoring write to CSR_SATP\n");
+                    printf("WARN: Ignoring write to CSR_SATP (%08x)\n", value);
                 return;
             }
             write_csr_raw(cpu, address, value);

src/main.c

@@ -6,8 +6,10 @@
 #include <fcntl.h>
 #include <string.h>
 #include <unistd.h>
+#include <signal.h>
 #include "types.h"
 #include "cpu.h"
+#include "uart.h"
 
 #include "../elfy/elfy.h"
 
@@ -31,6 +33,16 @@ void usage() {
     exit(EXIT_FAILURE);
 }
 
+static cpu_t cpu;
+
+void term(int signum)
+{
+   printf("\n\nCaught signal!\n");
+   cpu_dump(&cpu);
+   printf("\n");
+   exit(EXIT_FAILURE);
+}
+
 int main(int argc, char *argv[]) {
     char *elf = NULL;
     char *bin = NULL;
@@ -76,9 +88,15 @@ int main(int argc, char *argv[]) {
         memcpy(mem, bin_ptr, get_filesize(bin));
     }
 
-    uint8_t *dtb_ptr = get_mmap_ptr("./dts.dtb");
+    struct sigaction action;
+    memset(&action, 0, sizeof(action));
+    action.sa_handler = term;
+    sigaction(SIGTERM, &action, NULL);
+    sigaction(SIGINT, &action, NULL);
 
-    cpu_t cpu = cpu_init(mem, dtb_ptr);
+    fcntl(0, F_SETFL, O_NONBLOCK);
+
+    cpu = cpu_init(mem, dtb ? get_mmap_ptr(dtb) : NULL);
 
     if (VERBOSE >= 1)
         printf("CPU initialized!\n");
@@ -92,6 +110,11 @@ int main(int argc, char *argv[]) {
         if (VERBOSE >= 3)
             cpu_dump(&cpu);
 
+        /* char input = 0; */
+        /* if (!SINGLE_STEP && !uart_input_value && read(0, &input, 1)) { */
+        /*     uart_input_value = input; */
+        /* } */
+
         if (SINGLE_STEP) {
             fflush(stdout);
             fflush(stdin);
@@ -99,7 +122,7 @@ int main(int argc, char *argv[]) {
             gc: ch = getchar();
             switch (ch) {
                 case '\n': break;
-                case 'c': SINGLE_STEP = 0; break;
+                case 'c': SINGLE_STEP = false; break;
                 default: goto gc;
             }
         }

src/uart.h

@@ -4,6 +4,8 @@
 #include <stdio.h>
 #include "types.h"
 
+static uint uart_input_value = 0;
+
 const uint SHIFT_RBR = 0;
 const uint SHIFT_THR = 8;
 const uint SHIFT_IER = 16;
@@ -39,7 +41,8 @@ void uart_tick(cpu_t *cpu) {
     bool rx_ip = false;
 
     if ((cpu->clock % 0x38400) == 0 && UART_GET1(RBR) == 0) {
-        uint value = 0; // TODO: Add actual input logic
+        uint value = uart_input_value; // TODO: Add actual input logic
+        uart_input_value = 0;
         if (value != 0) {
             UART_SET1(RBR, value);
             UART_SET2(LSR, (UART_GET2(LSR) | LSR_DATA_AVAILABLE));
@@ -53,6 +56,7 @@ void uart_tick(cpu_t *cpu) {
     uint thr = UART_GET1(THR);
     if ((cpu->clock & 0x16) == 0 && thr != 0) {
         printf("%c", (char)thr);
+        fflush(stdout);
         UART_SET1(THR, 0);
         UART_SET2(LSR, (UART_GET2(LSR) | LSR_THR_EMPTY));
         uart_update_iir(cpu);

test.sh

@@ -19,8 +19,8 @@ function run_test {
 
     popd
 
-    echo "Running: ./rvc -e \"./riscv-tests/isa/$1\""
+    echo "Running: ./rvc -e \"./riscv-tests/isa/$1\" -v 1"
-    timeout 5s ./rvc -e "./riscv-tests/isa/$1"
+    timeout 5s ./rvc -e "./riscv-tests/isa/$1" -v 1
 
     if [ $? -gt 0 ]; then
         echo "Test failed!"