small fixes

qemu-debug.gdb

@@ -1,9 +1,8 @@
-target remote | qemu-system-i386 -m 768 -S -gdb stdio out/disk.img
+target remote | qemu-system-i386 -m 512 -S -gdb stdio out/disk.img
 add-symbol-file obj/kernel.elf
 add-symbol-file obj/init.elf
 set disassembly-flavor intel
 layout reg
 break main
 break panic
-break _before_start_task
 cont

src/kernel/idt.c

@@ -70,9 +70,7 @@ static char sc_get_key() {
 }
 
 static void *sc_allocate_ram(uint32_t pages) {
-//switch_to_kernel_cr3();
-  void *result = pd_user_allocate_anywhere_writable(active_task->page_directory, pages);
-//switch_to_task_cr3();
+  return pd_user_allocate_anywhere_writable(active_task->page_directory, pages);
 }
 
 void const *syscall_table[] = {
@@ -90,7 +88,7 @@ extern void syscall_isr;
 extern void quit_isr;
 extern void yield_isr;
 
-void register_int(uint8_t n, void *isr, uint8_t dpl) {
+static void register_int(uint8_t n, void *isr, uint8_t dpl) {
   idt[n].addr_low = (uint32_t)isr & 0xffff;
   idt[n].addr_high = (uint32_t)isr >> 16;
   idt[n].cs = 0x10;

src/kernel/idt.h

@@ -4,6 +4,5 @@
 #include <stdint.h>
 
 void init_idt();
-void enable_idt();
 
 #endif

src/kernel/isrs.asm

@@ -86,6 +86,9 @@ _before_start_task:
   iret
 
 _start_user_mode:
+  mov ax, 0x2b
+  mov ds, ax
+
   push dword 0x2b
   sub esp, 4
   push dword 0x00000200;interrupt flag

src/kernel/log.c

@@ -4,7 +4,7 @@
 #define INFO_COM COM1
 
 void init_log() {
-  vga_set_color(0x2f);
+  vga_set_color(0x30);
   vga_blank();
 }
 

src/kernel/main.c

@@ -12,6 +12,7 @@
 #include "pci.h"
 #include "log.h"
 #include "elf.h"
+#include "vga.h"
 
 void reset_tree();
 void tree(struct drive *d);
@@ -143,9 +144,8 @@ void main() {
   logsz(nbuf);
   logsz("k user memory free.\n");
 
-//while (1)
-//  asm ("hlt");
-
   init_idt();
+
+  vga_set_color(0x07);
   _start_user_mode();
 }

src/kernel/paging.c

@@ -45,7 +45,8 @@ void pd_map(void *pd, uint32_t physical_addr, uint32_t virtual_addr, bool writab
   ((uint32_t *)(*ptp & PE_ADDR_MASK))[(virtual_addr >> 12) % 1024] = physical_addr | PE_USER | PE_PRESENT | (PE_WRITABLE * writable);
 }
 
-bool pd_is_mapped(void *pd, uint32_t vma) {
+__attribute__ ((pure))
+static bool pd_is_mapped(void *pd, uint32_t vma) {
   uint32_t pde = ((uint32_t *)pd)[vma >> 22];
   return (pde & PE_PRESENT) && (((uint32_t *)(pde & PE_ADDR_MASK))[(vma >> 12) % 1024] & PE_PRESENT);
 }
@@ -85,7 +86,7 @@ void *pd_user_allocate(void *pd, uint32_t vma, uint32_t pages, bool writable) {
 void *pd_user_allocate_anywhere_writable(void *pd, uint32_t pages) {
   uint32_t run = 0;
   for (void *vma = (void *)KERNEL_END; vma; vma += 4096) {
-    if (pd_is_mapped(pd, vma))
+    if (pd_is_mapped(pd, (uint32_t)vma))
       run = 0;
     else if (++run == pages) {
       vma -= (pages - 1) * 4096;
@@ -94,6 +95,7 @@ void *pd_user_allocate_anywhere_writable(void *pd, uint32_t pages) {
       return vma;
     }
   }
+  return 0;
 }
 
 #define KPAGE_DIR     ((uint32_t *)0x00005000)

src/kernel/paging.h

@@ -6,7 +6,6 @@ void init_paging();
 void *new_pd();
 void free_pd(void *pd);
 void pd_map(void *pd, uint32_t physical_addr, uint32_t virtual_addr, bool writable);
-void switch_pd(void *pd);
 
 void free_task_pd(void *pd);
 void *new_task_pd();

src/kernel/task.c

@@ -1,6 +1,7 @@
 #include "panic.h"
 #include "task.h"
 #include "paging.h"
+#include "log.h"
 
 struct tss {
   struct tss *prev;
@@ -41,7 +42,7 @@ struct tss {
 
 #define MAX_TASKS 64
 
-struct task_state tasks[MAX_TASKS];
+static struct task_state tasks[MAX_TASKS];
 struct task_state *active_task;
 
 void init_tasks() {