-#include "mmu.h"
+/* This file is derived from source code used in MIT's 6.828
+ course. The original copyright notice is reproduced in full
+ below. */
+
+/*
+ * Copyright (C) 1997 Massachusetts Institute of Technology
+ *
+ * This software is being provided by the copyright holders under the
+ * following license. By obtaining, using and/or copying this software,
+ * you agree that you have read, understood, and will comply with the
+ * following terms and conditions:
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose and without fee or royalty is
+ * hereby granted, provided that the full text of this NOTICE appears on
+ * ALL copies of the software and documentation or portions thereof,
+ * including modifications, that you make.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO
+ * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE,
+ * BUT NOT LIMITATION, COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR
+ * WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR
+ * THAT THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY
+ * THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS. COPYRIGHT
+ * HOLDERS WILL BEAR NO LIABILITY FOR ANY USE OF THIS SOFTWARE OR
+ * DOCUMENTATION.
+ *
+ * The name and trademarks of copyright holders may NOT be used in
+ * advertising or publicity pertaining to the software without specific,
+ * written prior permission. Title to copyright in this software and any
+ * associated documentation will at all times remain with copyright
+ * holders. See the file AUTHORS which should have accompanied this software
+ * for a list of all copyright holders.
+ *
+ * This file may be derived from previously copyrighted software. This
+ * copyright applies only to those changes made by the copyright
+ * holders listed in the AUTHORS file. The rest of this file is covered by
+ * the copyright notices, if any, listed below.
+ */
+
+#include "threads/loader.h"
+#include "threads/mmu.h"
##############################################################################
# Kernel loader.
# first byte of the kernel, where start.S is linked.
##############################################################################
+/* Flags in control register 0 */
+#define CR0_PE 0x00000001 /* Protection Enable. */
+#define CR0_EM 0x00000004 /* (Floating-point) Emulation. */
+#define CR0_PG 0x80000000 /* Paging. */
+#define CR0_WP 0x00010000 /* Write-Protect enable in kernel mode. */
+
.globl start # Entry point
start: .code16 # This runs in real mode
cli # Disable interrupts
movl %cr0, %eax # turn on protected mode
orl $CR0_PE, %eax #
movl %eax, %cr0 #
- ### CPU magic: jump to relocation, flush prefetch queue, and reload %cs
- ### Has the effect of just jmp to the next instruction, but simultaneous
- ### loads CS with $PROT_MODE_CSEG.
+ ### CPU magic: jump to relocation, flush prefetch queue, and
+ ### reload %cs Has the effect of just jmp to the next
+ ### instruction, but simultaneous loads CS with
+ ### $PROT_MODE_CSEG.
ljmp $SEL_KCSEG, $protcseg
#### We are in protected mode in a 32-bit segment (hence the .code32)
movw %ax, %gs
movw %ax, %ss
-#### Load kernel at 1 MB by frobbing the IDE controller directly.
+#### Load kernel starting at physical address LOADER_KERN_BASE by
+#### frobbing the IDE controller directly.
movl $1, %ebx
- movl $0x100000, %edi
+ movl $LOADER_KERN_BASE, %edi
read_sector:
### Poll status register while controller busy.
cmpl $KERNEL_LOAD_PAGES*8 + 1, %ebx
jnz read_sector
-##### Create temporary PDE and PTE and set page directory pointer
+##### Create temporary page directory and page table, set page
+##### directory pointer, and turn on paging.
##### FIXME? We could use a single 4 MB page instead of 1024 4 kB pages.
- movl $0x10000, %edi
+ # Create page directory at 64 kB.
+ movl $0x10000, %edi
movl %edi, %cr3
+
+ # Fill page directory with zeroes.
subl %eax, %eax
movl $0x400, %ecx
rep stosl
+
+ # Set PDEs for 0 and LOADER_PHYS_BASE to point to the
+ # page table.
movl $0x11000 | PG_U | PG_W | PG_P, %eax
movl %eax, 0x10000
- movl %eax, 0x10c00
+ movl %eax, 0x10000 | (LOADER_PHYS_BASE >> 20)
+
+ # Initialize page table.
movl $PG_U | PG_W | PG_P, %eax
movl $0x400, %ecx
1: stosl
addl $0x1000, %eax
loop 1b
-##### Enable paging.
-
+ # Turn on paging and kernel write-protect.
movl %cr0, %eax
- orl $CR0_PG, %eax
+ orl $CR0_PG | CR0_WP, %eax
movl %eax, %cr0
jmp 1f
1:
##### Jump to kernel entry point.
- movl $0xc0007c00, %esp
- movl $0xc0100000, %eax
- jmp *%eax
+ movl $LOADER_PHYS_BASE + 0x20000, %esp
+ movl $LOADER_PHYS_BASE + LOADER_KERN_BASE, %eax
+ call *%eax
+ jmp panic
##### GDT
.ascii "Loader panic!\r\n"
.byte 0
-##### Command-line arguments inserted by another utility.
-##### The loader doesn't use these, but we note their
-##### location here for easy reference.
- .org 0x200 - 0x80
-cmd_line:
-
##### Memory size in 4 kB pages.
- .org 0x200 - 6
+ .org LOADER_RAM_PAGES - LOADER_BASE
ram_pages:
.long 0
+##### Command-line arguments inserted by another utility.
+##### The loader doesn't use these, but we note their
+##### location here for easy reference.
+ .org LOADER_CMD_LINE - LOADER_BASE
+cmd_line:
+ .fill 0x80, 1, 0
+
##### Boot-sector signature for BIOS inspection.
- .org 0x200 - 2
+ .org LOADER_BIOS_SIG - LOADER_BASE
.word 0xaa55
projects / pintos-anon / blobdiff