add printing pagetable location

kernel/make/x86_64/linker.ld

@@ -3,7 +3,7 @@ ENTRY(stivale2_main)
 SECTIONS
 {
     kernel_phys_offset = 0xffffffff80000000;
-    . = kernel_phys_offset + 0x100000;
+    . = kernel_phys_offset + 1M;
 
     .stivale2hdr ALIGN(4K) :
     {

kernel/src/allocator/arena.c

@@ -0,0 +1,17 @@
+/* An Arena allocator is a very basic allocator that simply discards free() calls. */
+
+#include "arena.h"
+#include <hal/ops.h>
+
+void* arena_alloc(struct arena_allocator* alloc, size_t len, size_t align) {
+    if(alloc->begin % align) {
+        alloc->begin += (align - alloc->begin % align);
+    }
+    if(alloc->length < len) {
+        PANIC("Attempt to allocate more memory than is available");
+    }
+    void* retval = (void*)alloc->begin;
+    alloc->begin += len;
+    alloc->length -= len;
+    return retval;
+}

kernel/src/allocator/arena.h

@@ -0,0 +1,8 @@
+#include <stddef.h>
+
+struct arena_allocator {
+    size_t begin;
+    size_t length;
+};
+
+void *arena_alloc(struct arena_allocator* alloc, size_t length, size_t align);

kernel/src/arch/x86_64/entry-stivale2.c

@@ -2,8 +2,10 @@
 #include <stdint.h>
 #include <stddef.h>
 
-#include "../../main.h"
-#include "arch/x86/stivale2-parse.h"
+#include <arch/x86/stivale2-parse.h>
+#include <print/print.h>
+
+#include <main.h>
 
 static uint8_t stack[4096] = {0};
 void stivale2_main(struct stivale2_struct *info);
@@ -28,6 +30,15 @@ void stivale2_main(struct stivale2_struct *info) {
     parse_stivale2(info);
     print_stivale2_memmap(info);
 
+    uint64_t* cr3;
+    __asm__ __volatile__ (
+        "movq %%cr3, %0\n\t"
+    : "=r" (cr3)
+    : /* no input */
+    : /* no clobbers */
+    );
+    printf("PAGE TABLE AT: %x\n", cr3);
+
 	char *argv[3] = {"stivale2", info->bootloader_brand, info->bootloader_version};
     kmain(3, argv);
 }