/* Copyright (C) 2004 The SOS Team
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/kmem_vmm.h>
#include <sos/kmalloc.h>
#include <sos/time.h>
#include <sos/thread.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 */
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++;
/* Execute the expired timeout actions (if any) */
sos_time_do_tick();
}
/* ======================================================================
* Page fault exception handling
*/
/* Helper function to dump a backtrace on bochs and/or the console */
static void dump_backtrace(const struct sos_cpu_state *cpu_state,
sos_vaddr_t stack_bottom,
sos_size_t stack_size,
sos_bool_t on_console,
sos_bool_t on_bochs)
{
void backtracer(sos_vaddr_t PC,
sos_vaddr_t params,
sos_ui32_t depth,
void *custom_arg)
{
sos_ui32_t invalid = 0xffffffff, *arg1, *arg2, *arg3, *arg4;
/* Get the address of the first 3 arguments from the
frame. Among these arguments, 0, 1, 2, 3 arguments might be
meaningful (depending on how many arguments the function may
take). */
arg1 = (sos_ui32_t*)params;
arg2 = (sos_ui32_t*)(params+4);
arg3 = (sos_ui32_t*)(params+8);
arg4 = (sos_ui32_t*)(params+12);
/* Make sure the addresses of these arguments fit inside the
stack boundaries */
#define INTERVAL_OK(b,v,u) ( ((b) <= (sos_vaddr_t)(v)) \
&& ((sos_vaddr_t)(v) < (u)) )
if (!INTERVAL_OK(stack_bottom, arg1, stack_bottom + stack_size))
arg1 = &invalid;
if (!INTERVAL_OK(stack_bottom, arg2, stack_bottom + stack_size))
arg2 = &invalid;
if (!INTERVAL_OK(stack_bottom, arg3, stack_bottom + stack_size))
arg3 = &invalid;
if (!INTERVAL_OK(stack_bottom, arg4, stack_bottom + stack_size))
arg4 = &invalid;
/* Print the function context for this frame */
if (on_bochs)
sos_bochs_printf("[%d] PC=0x%x arg1=0x%x arg2=0x%x arg3=0x%x\n",
(unsigned)depth, (unsigned)PC,
(unsigned)*arg1, (unsigned)*arg2,
(unsigned)*arg3);
if (on_console)
sos_x86_videomem_printf(23-depth, 3,
SOS_X86_VIDEO_BG_BLUE
| SOS_X86_VIDEO_FG_LTGREEN,
"[%d] PC=0x%x arg1=0x%x arg2=0x%x arg3=0x%x arg4=0x%x",
(unsigned)depth, PC,
(unsigned)*arg1, (unsigned)*arg2,
(unsigned)*arg3, (unsigned)*arg4);
}
sos_backtrace(cpu_state, 15, stack_bottom, stack_size, backtracer, NULL);
}
/* Page fault exception handler with demand paging for the kernel */
static void pgflt_ex(int intid, const struct sos_cpu_state *ctxt)
{
static sos_ui32_t demand_paging_count = 0;
sos_vaddr_t faulting_vaddr = sos_cpu_context_get_EX_faulting_vaddr(ctxt);
sos_paddr_t ppage_paddr;
/* Check if address is covered by any VMM range */
if (! sos_kmem_vmm_is_valid_vaddr(faulting_vaddr))
{
/* No: The page fault is out of any kernel virtual region. For
the moment, we don't handle this. */
dump_backtrace(ctxt,
bootstrap_stack_bottom,
bootstrap_stack_size,
TRUE, TRUE);
sos_display_fatal_error("Unresolved page Fault at instruction 0x%x on access to address 0x%x (info=%x)!",
sos_cpu_context_get_PC(ctxt),
(unsigned)faulting_vaddr,
(unsigned)sos_cpu_context_get_EX_info(ctxt));
SOS_ASSERT_FATAL(! "Got page fault (note: demand paging is disabled)");
}
/*
* Demand paging
*/
/* Update the number of demand paging requests handled */
demand_paging_count ++;
display_bits(0, 0,
SOS_X86_VIDEO_FG_LTRED | SOS_X86_VIDEO_BG_BLUE,
demand_paging_count);
/* Allocate a new page for the virtual address */
ppage_paddr = sos_physmem_ref_physpage_new(FALSE);
if (! ppage_paddr)
SOS_ASSERT_FATAL(! "TODO: implement swap. (Out of mem in demand paging because no swap for kernel yet !)");
SOS_ASSERT_FATAL(SOS_OK == sos_paging_map(ppage_paddr,
SOS_PAGE_ALIGN_INF(faulting_vaddr),
FALSE,
SOS_VM_MAP_PROT_READ
| SOS_VM_MAP_PROT_WRITE
| SOS_VM_MAP_ATOMIC));
sos_physmem_unref_physpage(ppage_paddr);
/* Ok, we can now return to interrupted context */
}
/* ======================================================================
* Demonstrate the use of SOS kernel threads
* - Kernel Threads are created with various priorities and their
* state is printed on both the console and the bochs' 0xe9 port
* - For tests regarding threads' synchronization, see mouse_sim.c
*/
struct thr_arg
{
char character;
int color;
int col;
int row;
};
static void demo_thread(void *arg)
{
struct thr_arg *thr_arg = (struct thr_arg*)arg;
int progress = 0;
sos_bochs_printf("start %c", thr_arg->character);
while (1)
{
progress ++;
display_bits(thr_arg->row, thr_arg->col+1, thr_arg->color, progress);
sos_bochs_putchar(thr_arg->character);
/* Yield the CPU to another thread sometimes... */
if ((random() % 100) == 0)
{
sos_bochs_printf("[37myield(%c)[m\n", thr_arg->character);
sos_x86_videomem_putchar(thr_arg->row, thr_arg->col, 0x1e, 'Y');
SOS_ASSERT_FATAL(SOS_OK == sos_thread_yield());
sos_x86_videomem_putchar(thr_arg->row, thr_arg->col, 0x1e, 'R');
}
/* Go to sleep some other times... */
else if ((random() % 200) == 0)
{
struct sos_time t = (struct sos_time){ .sec=0, .nanosec=50000000 };
sos_bochs_printf("[37msleep1(%c)[m\n", thr_arg->character);
sos_x86_videomem_putchar(thr_arg->row, thr_arg->col, 0x1e, 's');
SOS_ASSERT_FATAL(SOS_OK == sos_thread_sleep(& t));
SOS_ASSERT_FATAL(sos_time_is_zero(& t));
sos_x86_videomem_putchar(thr_arg->row, thr_arg->col, 0x1e, 'R');
}
/* Go to sleep for a longer time some other times... */
else if ((random() % 300) == 0)
{
struct sos_time t = (struct sos_time){ .sec=0, .nanosec=300000000 };
sos_bochs_printf("[37msleep2(%c)[m\n", thr_arg->character);
sos_x86_videomem_putchar(thr_arg->row, thr_arg->col, 0x1e, 'S');
SOS_ASSERT_FATAL(SOS_OK == sos_thread_sleep(& t));
SOS_ASSERT_FATAL(sos_time_is_zero(& t));
sos_x86_videomem_putchar(thr_arg->row, thr_arg->col, 0x1e, 'R');
}
/* Infinite loop otherwise */
}
}
static void test_thread()
{
/* "static" variables because we want them to remain even when the
function returns */
static struct thr_arg arg_b, arg_c, arg_d, arg_e, arg_R, arg_S;
sos_ui32_t flags;
sos_disable_IRQs(flags);
arg_b = (struct thr_arg) { .character='b', .col=0, .row=21, .color=0x14 };
sos_create_kernel_thread("YO[b]", demo_thread, (void*)&arg_b);
arg_c = (struct thr_arg) { .character='c', .col=46, .row=21, .color=0x14 };
sos_create_kernel_thread("YO[c]", demo_thread, (void*)&arg_c);
arg_d = (struct thr_arg) { .character='d', .col=0, .row=20, .color=0x14 };
sos_create_kernel_thread("YO[d]", demo_thread, (void*)&arg_d);
arg_e = (struct thr_arg) { .character='e', .col=0, .row=19, .color=0x14 };
sos_create_kernel_thread("YO[e]", demo_thread, (void*)&arg_e);
arg_R = (struct thr_arg) { .character='R', .col=0, .row=17, .color=0x1c };
sos_create_kernel_thread("YO[R]", demo_thread, (void*)&arg_R);
arg_S = (struct thr_arg) { .character='S', .col=0, .row=16, .color=0x1c };
sos_create_kernel_thread("YO[S]", demo_thread, (void*)&arg_S);
sos_restore_IRQs(flags);
}
/* ======================================================================
* An operating system MUST always have a ready thread ! Otherwise:
* what would the CPU have to execute ?!
*/
static void idle_thread()
{
sos_ui32_t idle_twiddle = 0;
while (1)
{
/* Remove this instruction if you get an "Invalid opcode" CPU
exception (old 80386 CPU) */
asm("hlt\n");
idle_twiddle ++;
display_bits(0, 0, SOS_X86_VIDEO_FG_GREEN | SOS_X86_VIDEO_BG_BLUE,
idle_twiddle);
/* Lend the CPU to some other thread */
sos_thread_yield();
}
}
/* ======================================================================
* 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;
struct sos_time tick_resolution;
/* 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 article 6.5", ',',
(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 article 6.5");
sos_bochs_putstring("Message in a bochs: This is SOS article 6.5.\n");
/* Setup CPU segmentation and IRQ subsystem */
sos_gdt_subsystem_setup();
sos_idt_subsystem_setup();
/* Setup SOS IRQs and exceptions subsystem */
sos_exception_subsystem_setup();
sos_irq_subsystem_setup();
/* Configure the timer so as to raise the IRQ0 at a 100Hz rate */
sos_i8254_set_frequency(100);
/* Setup the kernel time subsystem to get prepared to take the timer
ticks into account */
tick_resolution = (struct sos_time) { .sec=0, .nanosec=10000000UL };
sos_time_subsysem_setup(& tick_resolution);
/* 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;
}
/*
* Some interrupt handlers
*/
/* Binding some HW interrupts and exceptions to software routines */
sos_irq_set_routine(SOS_IRQ_TIMER,
clk_it);
/*
* Setup physical memory management
*/
/* 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_subsystem_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 */
SOS_ASSERT_FATAL(SOS_OK ==
sos_paging_subsystem_setup(sos_kernel_core_base_paddr,
sos_kernel_core_top_paddr));
/* Bind the page fault exception */
sos_exception_set_routine(SOS_EXCEPT_PAGE_FAULT,
pgflt_ex);
/*
* Setup kernel virtual memory allocator
*/
if (sos_kmem_vmm_subsystem_setup(sos_kernel_core_base_paddr,
sos_kernel_core_top_paddr,
bootstrap_stack_bottom,
bootstrap_stack_bottom
+ bootstrap_stack_size))
sos_bochs_printf("Could not setup the Kernel virtual space allocator\n");
if (sos_kmalloc_subsystem_setup())
sos_bochs_printf("Could not setup the Kmalloc subsystem\n");
/*
* Initialize the Kernel thread and scheduler subsystems
*/
/* Initialize kernel thread subsystem */
sos_thread_subsystem_setup(bootstrap_stack_bottom,
bootstrap_stack_size);
/* Initialize the scheduler */
sos_sched_subsystem_setup();
/* Declare the IDLE thread */
SOS_ASSERT_FATAL(sos_create_kernel_thread("idle", idle_thread, NULL) != NULL);
/* Enabling the HW interrupts here, this will make the timer HW
interrupt call the scheduler */
asm volatile ("sti\n");
/* Now run some Kernel threads just for fun ! */
extern void MouseSim();
MouseSim();
test_thread();
/*
* We can safely exit from this function now, for there is already
* an idle Kernel thread ready to make the CPU busy working...
*
* However, we must EXPLICITELY call sos_thread_exit() because a
* simple "return" will return nowhere ! Actually this first thread
* was initialized by the Grub bootstrap stage, at a time when the
* word "thread" did not exist. This means that the stack was not
* setup in order for a return here to call sos_thread_exit()
* automagically. Hence we must call it manually. This is the ONLY
* kernel thread where we must do this manually.
*/
sos_bochs_printf("Bye from primary thread !\n");
sos_thread_exit();
SOS_FATAL_ERROR("No trespassing !");
}
