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sortix--sortix/sortix/kernel.cpp
Jonas 'Sortie' Termansen 36b01eb2d3 Fixed the horrible 'nofoo' bug!
When compiled with gcc 4.6.1, 32-bit Sortix would triple fault during
early boot: When the TLB is being flushed, somehow a garbage value had
sneaked into Sortix::Memory::currentdir, and a non-page aligned (and
garbage) page directory is loaded. (Triple fault, here we come!)

However, adding a volatile addr_t foo after the currentdir variable
actually caused the system to boot correctly - the garbage was written
into that variable instead. To debug the problem, I set the foo value
to 0: as long as !foo (hence the name nofoo) everything was alright.

After closer examination I found that the initrd open code wrote to a
pointer supplied by kernel.cpp. The element pointed to was on the
stack. Worse, its address was the same as currentdir (now foo).

Indeed, the stack had gone into the kernel's data segment!

Turns out that this gcc configuration stores variables in the data
segment in the reverse order they are defined in, whereas previous
compilers did the opposite. The hack used to set up the stack during
early boot relied on this (now obviously incorrect) fact.

In effect, the stack was initialized to the end of the stack, not
the start of it: completely ignoring all the nice stack space
allocated in kernel.cpp.

I did not see that one coming.
2011-12-25 03:41:59 +01:00

314 lines
11 KiB
C++

/******************************************************************************
COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
This file is part of Sortix.
Sortix 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 3 of the License, or (at your option) any later
version.
Sortix 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 Sortix. If not, see <http://www.gnu.org/licenses/>.
kernel.cpp
A common interface shared by all devices that can be printed text to.
******************************************************************************/
#include "platform.h"
#include <libmaxsi/memory.h>
#include <libmaxsi/string.h>
#include <libmaxsi/format.h>
#include "log.h"
#include "panic.h"
#include "descriptor_tables.h"
#include "time.h"
#include "keyboard.h"
#include "multiboot.h"
#include "memorymanagement.h"
#include "thread.h"
#include "process.h"
#include "scheduler.h"
#include "syscall.h"
#include "pci.h"
#include "uart.h"
#include "serialterminal.h"
#include "vgaterminal.h"
#include "elf.h"
#include "initrd.h"
#include "vga.h"
#include "sound.h"
#include "io.h"
#include "pipe.h"
#include "filesystem.h"
#include "mount.h"
#include "directory.h"
#include "interrupt.h"
using namespace Maxsi;
void* RunApplication(void* Parameter);
// Keep the stack size aligned with $CPU/base.s
extern "C" { size_t stack[64*1024] = {0}; }
namespace Sortix
{
#ifdef PLATFORM_HTTP
namespace HTTP { void Init(); }
#endif
void DoBSoD()
{
#ifdef PLATFORM_SERIAL
UART::WriteChar(27);
UART::WriteChar(91);
UART::WriteChar(48 + 4);
UART::WriteChar(48 + 4);
UART::WriteChar(109);
#endif
Log::Print(" ");
Log::Print(" ");
Log::Print("Windows Boot Manager has experienced a problem. ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" Status: 0xc000000f ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" Info: An error occured during transferring execution. ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
Log::Print("You can try to recover the system with the Microsoft Windows System Recovery ");
Log::Print("Tools. (You might need to restart the system manually). ");
Log::Print(" ");
Log::Print("If the problem continues, please contact your system administrator or computer ");
Log::Print("manufacturer. ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
Log::Print(" ");
#ifdef JSSORTIX
JSSortix::Exit();
#else
while ( true ) { }
#endif
}
void DoMaxsiLogo()
{
Log::Print("\e[37;41m\e[2J"); // Make the background color red.
Log::Print(" _ \n");
Log::Print(" / \\ \n");
Log::Print(" /\\ /\\ / \\ \n");
Log::Print(" / \\ / \\ | | \n");
Log::Print(" / \\/ \\ | | \n");
Log::Print(" | O O \\_______________________ / | \n");
Log::Print(" | | \n");
Log::Print(" | \\_______/ / \n");
Log::Print(" \\ / \n");
Log::Print(" ------ --------------- ---/ \n");
Log::Print(" / \\ / \\ \n");
Log::Print(" / \\ / \\ \n");
Log::Print(" / \\ / \\ \n");
Log::Print(" /_____________\\ /____________\\ \n");
Log::Print(" \n");
Log::Print(" BOOTING OPERATING SYSTEM... ");
}
void DoWelcome()
{
#ifdef BSOD
DoBSoD();
#endif
DoMaxsiLogo();
}
extern "C" void KernelInit(unsigned long Magic, multiboot_info_t* BootInfo)
{
#ifdef JSSORTIX
// TODO: Make JSVM multiboot compliant.
multiboot_info_t MBInfo; BootInfo = &MBInfo;
multiboot_memory_map_t MBMMap;
MBMMap.addr = 0x100000;
MBMMap.len = 0xC00000;
MBMMap.type = MULTIBOOT_MEMORY_AVAILABLE;
MBMMap.size = sizeof(MBMMap) - sizeof(MBMMap.size);
BootInfo->flags = MULTIBOOT_INFO_MEM_MAP;
BootInfo->mmap_addr = (multiboot_uint32_t) &MBMMap;
BootInfo->mmap_length = sizeof(MBMMap);
#endif
// Initialize system calls.
Syscall::Init();
// Initialize the default terminal.
Maxsi::Format::Callback logcallback;
void* logpointer;
#if PLATFORM_SERIAL
// Initialize the serial driver.
UART::Init();
SerialTerminal::Init();
logcallback = SerialTerminal::Print;
logpointer = NULL;
#else
VGATerminal::Init();
logcallback = VGATerminal::Print;
logpointer = NULL;
#endif
// Initialize the kernel log.
Log::Init(logcallback, logpointer);
// Display the boot welcome screen.
DoWelcome();
if ( BootInfo == NULL ) { Panic("kernel.cpp: The bootinfo structure was NULL. Are your bootloader multiboot compliant?"); }
addr_t initrd = NULL;
size_t initrdsize = 0;
#ifndef JSSORTIX
uint32_t* modules = (uint32_t*) BootInfo->mods_addr;
for ( uint32_t I = 0; I < BootInfo->mods_count; I++ )
{
initrdsize = modules[2*I+1] - modules[2*I+0];
initrd = (addr_t) modules[2*I+0];
break;
}
if ( !initrd ) { PanicF("No init ramdisk provided"); }
#else
// TODO: UGLY HACK because JSVM doesn't support multiboot yet!
initrd = (addr_t) 0x180000UL;
initrdsize = 0x280000; // 2 MiB 512 KiB
#endif
Memory::RegisterInitRDSize(initrdsize);
#ifndef JSSORTIX
// Search for PCI devices and load their drivers.
PCI::Init();
#endif
// Initialize the paging and virtual memory.
Memory::Init(BootInfo);
// Initialize the GDT and TSS structures.
GDT::Init();
// Initialize the interrupt handler table to zeroes.
Interrupt::Init();
// Initialize the interrupt descriptor tables (enabling interrupts).
IDT::Init();
// Initialize the kernel heap.
Maxsi::Memory::Init();
// Initialize the keyboard.
Keyboard::Init();
// Initialize the VGA driver.
VGA::Init();
// Initialize the sound driver.
Sound::Init();
// Initialize the process system.
Process::Init();
// Initialize the thread system.
Thread::Init();
// Initialize the IO system.
IO::Init();
// Initialize the pipe system.
Pipe::Init();
// Initialize the filesystem system.
FileSystem::Init();
// Initialize the directory system.
Directory::Init();
// Initialize the mount system.
Mount::Init();
// Initialize the scheduler.
Scheduler::Init();
// Set up the initial ram disk.
InitRD::Init(initrd, initrdsize);
// Alright, now the system's drivers are loaded and initialized. It is
// time to load the initial user-space programs and start execution of
// the actual operating system.
byte* program;
size_t programsize;
// Create an address space for the idle process.
addr_t idleaddrspace = Memory::Fork();
if ( !idleaddrspace ) { Panic("could not fork an idle process address space"); }
// Create an address space for the initial process.
addr_t initaddrspace = Memory::Fork();
if ( !initaddrspace ) { Panic("could not fork an initial process address space"); }
// Create the system idle process.
Process* idle = new Process;
if ( !idle ) { Panic("could not allocate idle process"); }
idle->addrspace = idleaddrspace;
Memory::SwitchAddressSpace(idleaddrspace);
Scheduler::SetDummyThreadOwner(idle);
program = InitRD::Open("idle", &programsize);
if ( program == NULL ) { PanicF("initrd did not contain 'idle'"); }
addr_t idlestart = ELF::Construct(idle, program, programsize);
if ( !idlestart ) { Panic("could not construct ELF image for idle process"); }
Thread* idlethread = CreateThread(idlestart);
if ( !idlethread ) { Panic("could not create thread for the idle process"); }
Scheduler::SetIdleThread(idlethread);
// Create the initial process.
Process* init = new Process;
if ( !init ) { Panic("could not allocate init process"); }
init->addrspace = initaddrspace;
Memory::SwitchAddressSpace(initaddrspace);
Scheduler::SetDummyThreadOwner(init);
program = InitRD::Open("init", &programsize);
if ( program == NULL ) { PanicF("initrd did not contain 'init'"); }
addr_t initstart = ELF::Construct(init, program, programsize);
if ( !initstart ) { Panic("could not construct ELF image for init process"); }
Thread* initthread = CreateThread(initstart);
if ( !initthread ) { Panic("could not create thread for the init process"); }
Scheduler::SetInitProcess(init);
// Lastly set up the timer driver and we are ready to run the OS.
Time::Init();
// Run the OS.
Scheduler::MainLoop();
}
}