Implemented memory map routines

kernel/arch/i386/linker.ld

@@ -10,35 +10,52 @@ SECTIONS {
 
     . = 0x00100000;
 
-    /*
-     * Align all sections from all files to a 4KB boundary.
-     *
-     */
+    /* Align all sections from all files to a 4KB boundary. */
+
+    _kernel_start = .;
+    _kernel_text_start = .;
 
     .text ALIGN (0x1000) : {
         *(.multiboot)
         *(.text)
     }
 
+    _kernel_text_end = .;
+    _kernel_rodata_start = .;
+
     .rodata ALIGN (0x1000) : {
         *(.rodata*)
     }
 
+    _kernel_rodata_end = .;
+    _kernel_data_start = .;
+
     .data ALIGN (0x1000) : {
         *(.data)
     }
 
-    /*
-     * Note:
-     *  COMMON section keeps data objects that are not yet allocated,
-     *  this is just a prelinking section, it will be transformed into bss
-     *  and data after linking.
-     *
-     */
+    _kernel_data_end = .;
+    _kernel_bss_start = .;
 
     .bss ALIGN (0x1000) : {
         *(COMMON)
         *(.bss)
     }
 
+    _kernel_bss_end = .;
+    _kernel_end = .;
+
+    /DISCARD/ : {
+        *(.comment)
+        *(.note.gnu.build-id)
+    }
+
 }
+
+/*
+ * Note:
+ *  COMMON section keeps data objects that are not yet allocated,
+ *  this is just a prelinking section, it will be transformed into bss
+ *  and data after linking.
+ *
+ */

kernel/include/kernel/pmm.h

@@ -6,7 +6,7 @@
 /*
  * print_memory_map
  *  Using the multiboot structure, print memory regions, size
- *  of physical memory and info about kernel sections.
+ *  of physical memory.
  *
  * @param mb_info - Multiboot info
  *
@@ -14,4 +14,12 @@
 
 void print_memory_map(multiboot_info_t *mb_info);
 
+/*
+ * print_ksections
+ *  Print the layout of the kernel in memory.
+ *
+ */
+
+void print_kernel_map(void);
+
 #endif

kernel/kernel/kernel.c

@@ -24,6 +24,8 @@ void kmain(multiboot_info_t *mb_info, uint32_t mb_magic) {
         panic("Not a multiboot bootloader!");
 
     print_memory_map(mb_info);
+    puts("");
+    print_kernel_map();
 
     serial_init(COM1);
 

kernel/pmm/src/kmap.c

@@ -0,0 +1,30 @@
+#include "kernel/pmm.h"
+
+#include <stdio.h>
+#include <stdint.h>
+
+extern uint8_t *_kernel_start;
+extern uint8_t *_kernel_end;
+
+extern uint8_t *_kernel_text_start;
+extern uint8_t *_kernel_text_end;
+
+extern uint8_t *_kernel_rodata_start;
+extern uint8_t *_kernel_rodata_end;
+
+extern uint8_t *_kernel_data_start;
+extern uint8_t *_kernel_data_end;
+
+extern uint8_t *_kernel_bss_start;
+extern uint8_t *_kernel_bss_end;
+
+void print_kernel_map(void) {
+
+    printf("Kernel Memory Map:\n");
+    printf("kernel: 0x%x - 0x%x\n", &_kernel_start, &_kernel_end);
+    printf("text: 0x%x - 0x%x\n", &_kernel_text_start, &_kernel_text_end);
+    printf("rodata: 0x%x - 0x%x\n", &_kernel_rodata_start, &_kernel_rodata_end);
+    printf("data: 0x%x - 0x%x\n", &_kernel_data_start, &_kernel_data_end);
+    printf("bss: 0x%x - 0x%x\n", &_kernel_bss_start, &_kernel_bss_end);
+
+}

kernel/pmm/src/mmap.c

@@ -0,0 +1,45 @@
+#include "kernel/pmm.h"
+
+#include <stdio.h>
+#include <stdint.h>
+
+/* Defined in kernel/multiboot.h as macros. */
+
+static char *mem_types[] = {
+
+    "(Available)",
+    "(Reserved)",
+    "(ACPI Reclaimable)",
+    "(ACPI NVS)",
+    "(BadRAM)"
+
+};
+
+/*
+ * print_memory_map:
+ * -----------------
+ *
+ *  Extract mmap_addr from mb_info and iterate through all avaialble
+ *  memory zones.
+ *
+ */
+
+void print_memory_map(multiboot_info_t *mb_info) {
+
+    printf("Physical Memory Map:\n");
+
+    multiboot_memory_map_t *mmap =
+        (multiboot_memory_map_t *) mb_info->mmap_addr;
+
+    multiboot_memory_map_t *mmap_end =
+        (multiboot_memory_map_t *) (mb_info->mmap_addr + mb_info->mmap_length);
+
+    for (int i = 0; mmap < mmap_end; mmap++, i++) {
+
+        printf("region: %d start: 0x%x length: 0x%x type: %d ", i,
+                (uint32_t) mmap->addr, (uint32_t) mmap->len, mmap->type);
+        printf("%s\n", mem_types[mmap->type - 1]);
+
+    }
+
+}