/* Copyright (C) 2004 The SOS Team
Copyright (C) 1999 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.
*/
/* Include definitions of the multiboot standard */
#include <bootstrap/multiboot.h>
#include <hwcore/idt.h>
#include <hwcore/gdt.h>
#include <hwcore/irq.h>
#include <hwcore/exception.h>
#include <hwcore/i8254.h>
#include <sos/list.h>
#include <sos/physmem.h>
#include <hwcore/paging.h>
#include <sos/list.h>
#include <sos/klibc.h>
#include <sos/assert.h>
#include <drivers/x86_videomem.h>
#include <drivers/bochs.h>
/* Helper function to display each bits of a 32bits integer on the
screen as dark or light carrets */
static void display_bits(unsigned char row, unsigned char col,
unsigned char attribute,
sos_ui32_t integer)
{
int i;
/* Scan each bit of the integer, MSb first */
for (i = 31 ; i >= 0 ; i--)
{
/* Test if bit i of 'integer' is set */
int bit_i = (integer & (1 << i));
/* Ascii 219 => dark carret, Ascii 177 => light carret */
unsigned char ascii_code = bit_i?219:177;
sos_x86_videomem_putchar(row, col++,
attribute,
ascii_code);
}
}
/* Clock IRQ handler */
static void clk_it(int intid)
{
static sos_ui32_t clock_count = 0;
display_bits(0, 48,
SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
clock_count);
clock_count++;
}
/* Page fault exception handler */
static void pgflt_ex(int exid)
{
sos_bochs_printf("Got page fault\n");
sos_x86_videomem_printf(10, 30,
SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
"Got EXPECTED (?) Page fault ! But where ???");
for (;;) ;
}
static void test_paging(sos_vaddr_t sos_kernel_core_top_vaddr)
{
/* The (linear) address of the page holding the code we are
currently executing */
sos_vaddr_t vpage_code = SOS_PAGE_ALIGN_INF(test_paging);
/* The new physical page that will hold the code */
sos_paddr_t ppage_new;
/* Where this page will be mapped temporarily in order to copy the
code into it: right after the kernel code/data */
sos_vaddr_t vpage_tmp = sos_kernel_core_top_vaddr;
unsigned i;
/* Bind the page fault exception to one of our routines */
sos_exception_set_routine(SOS_EXCEPT_PAGE_FAULT,
pgflt_ex);
/*
* Test 1: move the page where we execute the code elsewhere in
* physical memory
*/
sos_x86_videomem_printf(4, 0,
SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
"Moving current code elsewhere in physical memory:");
/* Allocate a new physical page */
ppage_new = sos_physmem_ref_physpage_new(FALSE);
if (! ppage_new)
{
/* STOP ! No memory left */
sos_x86_videomem_putstring(20, 0,
SOS_X86_VIDEO_FG_LTRED
| SOS_X86_VIDEO_BG_BLUE,
"test_paging : Cannot allocate page");
return;
}
sos_x86_videomem_printf(5, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Hello from the address 0x%x in physical memory",
sos_paging_get_paddr(vpage_code));
sos_x86_videomem_printf(6, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Transfer vpage 0x%x: ppage 0x%x -> 0x%x (tmp vpage 0x%x)",
vpage_code,
sos_paging_get_paddr(vpage_code),
ppage_new,
(unsigned)vpage_tmp);
/* Map the page somewhere (right after the kernel mapping) in order
to copy the code we are currently executing */
sos_paging_map(ppage_new, vpage_tmp,
FALSE,
SOS_VM_MAP_ATOMIC
| SOS_VM_MAP_PROT_READ
| SOS_VM_MAP_PROT_WRITE);
/* Ok, the new page is referenced by the mapping, we can release our
reference to it */
sos_physmem_unref_physpage(ppage_new);
/* Copy the contents of the current page of code to this new page
mapping */
memcpy((void*)vpage_tmp,
(void*)vpage_code,
SOS_PAGE_SIZE);
/* Transfer the mapping of the current page of code to this new page */
sos_paging_map(ppage_new, vpage_code,
FALSE,
SOS_VM_MAP_ATOMIC
| SOS_VM_MAP_PROT_READ
| SOS_VM_MAP_PROT_WRITE);
/* Ok, here we are: we have changed the physcal page that holds the
code we are executing ;). However, this new page is mapped at 2
virtual addresses:
- vpage_tmp
- vpage_code
We can safely unmap it from sos_kernel_core_top_vaddr, while
still keeping the vpage_code mapping */
sos_paging_unmap(vpage_tmp);
sos_x86_videomem_printf(7, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Hello from the address 0x%x in physical memory",
sos_paging_get_paddr(vpage_code));
sos_x86_videomem_printf(9, 0,
SOS_X86_VIDEO_FG_LTGREEN | SOS_X86_VIDEO_BG_BLUE,
"Provoking a page fault:");
/*
* Test 2: make sure the #PF handler works
*/
/* Scan part of the kernel up to a page fault. This page fault
should occur on the first page unmapped after the kernel area,
which is exactly the page we temporarily mapped/unmapped
(vpage_tmp) above to move the kernel code we are executing */
for (i = vpage_code ; /* none */ ; i += SOS_PAGE_SIZE)
{
unsigned *pint = (unsigned *)SOS_PAGE_ALIGN_INF(i);
sos_bochs_printf("Test vaddr 0x%x : val=", (unsigned)pint);
sos_x86_videomem_printf(10, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Test vaddr 0x%x : val= ",
(unsigned)pint);
sos_bochs_printf("0x%x\n", *pint);
sos_x86_videomem_printf(10, 30,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"0x%x ", *pint);
}
/* BAD ! Did not get the page fault... */
sos_x86_videomem_printf(20, 0,
SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
"We should have had a #PF at vaddr 0x%x !",
vpage_tmp);
}
/* The C entry point of our operating system */
void sos_main(unsigned long magic, unsigned long addr)
{
unsigned i;
sos_paddr_t sos_kernel_core_base_paddr, sos_kernel_core_top_paddr;
/* Grub sends us a structure, called multiboot_info_t with a lot of
precious informations about the system, see the multiboot
documentation for more information. */
multiboot_info_t *mbi;
mbi = (multiboot_info_t *) addr;
/* Setup bochs and console, and clear the console */
sos_bochs_setup();
sos_x86_videomem_setup();
sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLUE);
/* Greetings from SOS */
if (magic == MULTIBOOT_BOOTLOADER_MAGIC)
/* Loaded with Grub */
sos_x86_videomem_printf(1, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Welcome From GRUB to %s%c RAM is %dMB (upper mem = 0x%x kB)",
"SOS", ',',
(unsigned)(mbi->mem_upper >> 10) + 1,
(unsigned)mbi->mem_upper);
else
/* Not loaded with grub */
sos_x86_videomem_printf(1, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Welcome to SOS");
sos_bochs_putstring("Message in a bochs\n");
/* Setup CPU segmentation and IRQ subsystem */
sos_gdt_setup();
sos_idt_setup();
/* Setup SOS IRQs and exceptions subsystem */
sos_exceptions_setup();
sos_irq_setup();
/* Configure the timer so as to raise the IRQ0 at a 100Hz rate */
sos_i8254_set_frequency(100);
/* We need a multiboot-compliant boot loader to get the size of the RAM */
if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
{
sos_x86_videomem_putstring(20, 0,
SOS_X86_VIDEO_FG_LTRED
| SOS_X86_VIDEO_BG_BLUE
| SOS_X86_VIDEO_FG_BLINKING,
"I'm not loaded with Grub !");
/* STOP ! */
for (;;)
continue;
}
/* Binding some HW interrupts and exceptions to software routines */
sos_irq_set_routine(SOS_IRQ_TIMER,
clk_it);
/* Enabling the HW interrupts here, this will make the timer HW
interrupt call our clk_it handler */
asm volatile ("sti\n");
/* Multiboot says: "The value returned for upper memory is maximally
the address of the first upper memory hole minus 1 megabyte.". It
also adds: "It is not guaranteed to be this value." aka "YMMV" ;) */
sos_physmem_setup((mbi->mem_upper<<10) + (1<<20),
& sos_kernel_core_base_paddr,
& sos_kernel_core_top_paddr);
/*
* Switch to paged-memory mode
*/
/* Disabling interrupts should seem more correct, but it's not really
necessary at this stage */
if (sos_paging_setup(sos_kernel_core_base_paddr,
sos_kernel_core_top_paddr))
sos_bochs_printf("Could not setup paged memory mode\n");
sos_x86_videomem_printf(2, 0,
SOS_X86_VIDEO_FG_YELLOW | SOS_X86_VIDEO_BG_BLUE,
"Paged-memory mode is activated");
test_paging(sos_kernel_core_top_paddr);
/* An operatig system never ends */
for (;;)
continue;
return;
}
