create ringbuffer for logging

4 files changed, 122 insertions, 4 deletions

diff --git a/include/log.h b/include/log.h
new file mode 100644
index 0000000..2b35922
--- /dev/null
+++ b/include/log.h
@@ -0,0 +1,6 @@
+#pragma once
+
+#define RINGBUF_SIZE 64 * 1024
+
+void vprintk(const char *message, __builtin_va_list args);
+void printk(const char *message, ...);
diff --git a/kernel/kernel.c b/kernel/kernel.c
index da44428..70a0ad8 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -1,19 +1,26 @@
 #include <types.h>
 #include <dtb.h>
 #include <bump.h>
+#include <log.h>
+
+uint32_t user_regs[31];
 
 void kernel_main(size_t hart, void *fdt) {
-    (void)hart;
+    printk("Doing kernel init with hard ID %d", hart);
 
     struct dt_node *head = dt_parse(fdt);
     struct mem_info *info = km_find_memory(head);
 
+
     if (!info) {
-        while (1);
+        printk("failed to find memory info!");
+        return;
     }
 
     km_init(info);
+}
 
+void kernel_trap() {
 
-    while(1);
+    
 }
diff --git a/kernel/log.c b/kernel/log.c
new file mode 100644
index 0000000..3392223
--- /dev/null
+++ b/kernel/log.c
@@ -0,0 +1,96 @@
+#include <log.h>
+#include <types.h>
+__attribute__((section(".ringbuf"), aligned(64)))
+volatile char log_ring[RINGBUF_SIZE];
+static int pos = 0;
+
+void put_char(char c) {
+    log_ring[pos++] = c;
+    if (pos >= RINGBUF_SIZE)
+        pos = 0;
+}
+
+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);
+}
diff --git a/linker.ld b/linker.ld
index 4f86e10..5bf6586 100644
--- a/linker.ld
+++ b/linker.ld
@@ -4,7 +4,8 @@ ENTRY(_start)
 MEMORY
 {
     ROM   (rx)  : ORIGIN = 0x80000000, LENGTH = 1M
-    RAM   (rwx) : ORIGIN = 0x80400000, LENGTH = 1M
+    RAM   (rwx) : ORIGIN = 0x81000000, LENGTH = 1M
+    LOGRAM (rw) : ORIGIN = 0x82000000, LENGTH = 1M
 }
 
 SECTIONS
@@ -51,6 +52,14 @@ SECTIONS
         __stack_top = .;
     } > RAM
 
+    .ringbuf (NOLOAD) : ALIGN(64)
+    {
+        __ringbuf_start = .;
+        KEEP(*(.ringbuf))
+        . = ALIGN(64);
+        __ringbuf_end = .;
+    } > LOGRAM
+
     /DISCARD/ : {
         *(.eh_frame)
         *(.eh_frame.*)