scaffold kernel from parts of wkern x86

4 files changed, 184 insertions, 0 deletions

diff --git a/website-kernel/arch/kernel.c b/website-kernel/arch/kernel.c
new file mode 100644
index 0000000..28c94d3
--- /dev/null
+++ b/website-kernel/arch/kernel.c
@@ -0,0 +1,9 @@
+#include <int.h>
+#include <log.h>
+
+#define SERIAL_PORT 0x70000000
+
+void kernel_main(size_t hart) {
+    (void)hart;
+    printk("wkern version %s (Compiler %s, Linker %s) on %s\n", VERSION, COMPILER_NAME, LINKER_NAME, ARCH_NAME);
+}
diff --git a/website-kernel/arch/linker.ld b/website-kernel/arch/linker.ld
new file mode 100644
index 0000000..52a3a05
--- /dev/null
+++ b/website-kernel/arch/linker.ld
@@ -0,0 +1,52 @@
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+
+MEMORY
+{
+    ROM (rx) : ORIGIN = 0x80000000, LENGTH = 1M
+    RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 4M
+}
+
+SECTIONS
+{
+    .text : {
+        KEEP(*(.text._start))
+        KEEP(*(.text.start))
+        *(.text)
+        *(.text.*)
+    } > ROM
+    .rodata : {
+        *(.rodata)
+        *(.rodata.*)
+    } > ROM
+
+    .init_array : {
+        __init_array_start = .;
+        KEEP(*(.init_array))
+        KEEP(*(.init_array.*))
+        __init_array_end = .;
+    } > ROM
+
+    .data : {
+        __data_start = .;
+        *(.data)
+        *(.data.*)
+        __data_end = .;
+    } > RAM AT> ROM
+    __data_load = LOADADDR(.data);
+
+    .bss : {
+        __bss_start = .;
+        *(.bss)
+        *(.bss.*)
+        *(COMMON)
+        __bss_end = .;
+    } > RAM
+
+    .stack (NOLOAD) : {
+        . = ALIGN(16);
+        __stack_bottom = .;
+        . += 8K;
+        __stack_top = .;
+    } > RAM
+}
diff --git a/website-kernel/arch/log.c b/website-kernel/arch/log.c
new file mode 100644
index 0000000..63e0615
--- /dev/null
+++ b/website-kernel/arch/log.c
@@ -0,0 +1,100 @@
+#include <log.h>
+void stub(char c) {
+    (void)c;
+    return;
+}
+
+console_callback_t callback = stub;
+
+void put_char(char c) {
+    callback(c);
+}
+
+void put_string(const char *s) {
+    while (*s)
+        put_char(*s++);
+}
+
+void put_uint(unsigned int value, unsigned int radix) {
+    char tmp[16];
+    const char digits[] = "0123456789abcdef";
+    int i = 0;
+
+    if (value == 0) {
+        put_char('0');
+        return;
+    }
+
+    while (value) {
+        tmp[i++] = digits[value % radix];
+        value /= radix;
+    }
+
+    while (i--)
+        put_char(tmp[i]);
+}
+
+void put_int(int value) {
+    if (value < 0) {
+        put_char('-');
+        put_uint((unsigned int)(-value), 10);
+    } else {
+        put_uint((unsigned int)value, 10);
+    }
+}
+
+void vprintk(const char *fmt, __builtin_va_list args) {
+    while (*fmt) {
+        if (*fmt != '%') {
+            put_char(*fmt++);
+            continue;
+        }
+
+        fmt++;
+
+        switch (*fmt) {
+        case '%':
+            put_char('%');
+            break;
+
+        case 'c':
+            put_char((char)__builtin_va_arg(args, int));
+            break;
+
+        case 's':
+            put_string(__builtin_va_arg(args, const char *));
+            break;
+
+        case 'd':
+        case 'i':
+            put_int(__builtin_va_arg(args, int));
+            break;
+
+        case 'u':
+            put_uint(__builtin_va_arg(args, unsigned int), 10);
+            break;
+
+        case 'x':
+            put_uint(__builtin_va_arg(args, unsigned int), 16);
+            break;
+
+        default:
+            put_char('%');
+            put_char(*fmt);
+            break;
+        }
+
+        fmt++;
+    }
+}
+
+void printk(const char *fmt, ...) {
+    __builtin_va_list args;
+    __builtin_va_start(args, fmt);
+    vprintk(fmt, args);
+    __builtin_va_end(args);
+}
+
+void register_console_callback(console_callback_t cb) {
+    callback = cb;
+}
diff --git a/website-kernel/arch/start.S b/website-kernel/arch/start.S
new file mode 100644
index 0000000..8248ab9
--- /dev/null
+++ b/website-kernel/arch/start.S
@@ -0,0 +1,23 @@
+.section .text._start
+.global _start
+.type _start, @function
+
+.extern user_regs
+
+_start:
+    csrw sstatus, zero
+    csrw sie, zero
+
+    la sp, __stack_top
+    
+    la t0, __bss_start
+    la t1, __bss_end
+    beq t0, t1, 2f
+1:
+    sw zero, 0(t0)
+    addi t0, t0, 4
+    bltu t0, t1, 1b
+2:
+    call kernel_main
+    wfi
+