ladybird/Kernel/init.cpp

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "Devices/PATADiskDevice.h"
#include "KSyms.h"
#include "Process.h"
#include "RTC.h"
#include "Scheduler.h"
#include <AK/Types.h>
#include <Kernel/ACPI/ACPIDynamicParser.h>
#include <Kernel/ACPI/ACPIStaticParser.h>
#include <Kernel/ACPI/DMIDecoder.h>
#include <Kernel/ACPI/MultiProcessorParser.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/CMOS.h>
#include <Kernel/Devices/BXVGADevice.h>
#include <Kernel/Devices/DebugLogDevice.h>
#include <Kernel/Devices/DiskPartition.h>
#include <Kernel/Devices/EBRPartitionTable.h>
#include <Kernel/Devices/FullDevice.h>
#include <Kernel/Devices/GPTPartitionTable.h>
#include <Kernel/Devices/KeyboardDevice.h>
#include <Kernel/Devices/MBRPartitionTable.h>
#include <Kernel/Devices/MBVGADevice.h>
#include <Kernel/Devices/NullDevice.h>
#include <Kernel/Devices/PATAChannel.h>
#include <Kernel/Devices/PS2MouseDevice.h>
#include <Kernel/Devices/RandomDevice.h>
#include <Kernel/Devices/SB16.h>
#include <Kernel/Devices/SerialDevice.h>
#include <Kernel/Devices/VMWareBackdoor.h>
#include <Kernel/Devices/ZeroDevice.h>
#include <Kernel/FileSystem/Ext2FileSystem.h>
#include <Kernel/FileSystem/VirtualFileSystem.h>
#include <Kernel/Heap/SlabAllocator.h>
#include <Kernel/Heap/kmalloc.h>
#include <Kernel/Interrupts/APIC.h>
#include <Kernel/Interrupts/InterruptManagement.h>
#include <Kernel/Interrupts/PIC.h>
#include <Kernel/KParams.h>
#include <Kernel/Multiboot.h>
#include <Kernel/Net/LoopbackAdapter.h>
#include <Kernel/Net/NetworkTask.h>
#include <Kernel/PCI/Access.h>
#include <Kernel/PCI/Initializer.h>
#include <Kernel/Random.h>
#include <Kernel/TTY/PTYMultiplexer.h>
#include <Kernel/TTY/VirtualConsole.h>
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
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#include <Kernel/Time/TimeManagement.h>
#include <Kernel/VM/MemoryManager.h>
// Defined in the linker script
typedef void (*ctor_func_t)();
extern ctor_func_t start_ctors;
extern ctor_func_t end_ctors;
extern u32 __stack_chk_guard;
u32 __stack_chk_guard;
namespace Kernel {
[[noreturn]] static void init_stage2();
static void setup_serial_debug();
static void setup_acpi();
static void setup_vmmouse();
static void setup_pci();
static void setup_interrupts();
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
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static void setup_time_management();
VirtualConsole* tty0;
extern "C" [[noreturn]] void init()
{
setup_serial_debug();
cpu_setup();
kmalloc_init();
slab_alloc_init();
new KParams(String(reinterpret_cast<const char*>(low_physical_to_virtual(multiboot_info_ptr->cmdline))));
MemoryManager::initialize();
bool text_debug = KParams::the().has("text_debug");
gdt_init();
idt_init();
setup_interrupts();
setup_acpi();
new VFS;
new DebugLogDevice;
new Console;
klog() << "Starting SerenityOS...";
__stack_chk_guard = get_good_random<u32>();
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
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setup_time_management();
// call global constructors after gtd and itd init
for (ctor_func_t* ctor = &start_ctors; ctor < &end_ctors; ctor++)
(*ctor)();
new KeyboardDevice;
new PS2MouseDevice;
setup_vmmouse();
new SB16;
new NullDevice;
if (!get_serial_debug())
new SerialDevice(SERIAL_COM1_ADDR, 64);
new SerialDevice(SERIAL_COM2_ADDR, 65);
new SerialDevice(SERIAL_COM3_ADDR, 66);
new SerialDevice(SERIAL_COM4_ADDR, 67);
VirtualConsole::initialize();
tty0 = new VirtualConsole(0, VirtualConsole::AdoptCurrentVGABuffer);
new VirtualConsole(1);
VirtualConsole::switch_to(0);
// Sample test to see if the ACPI parser is working...
klog() << "ACPI: HPET table @ " << ACPI::Parser::the().find_table("HPET");
setup_pci();
if (text_debug) {
dbg() << "Text mode enabled";
} else {
if (multiboot_info_ptr->framebuffer_type == 1 || multiboot_info_ptr->framebuffer_type == 2) {
new MBVGADevice(
PhysicalAddress((u32)(multiboot_info_ptr->framebuffer_addr)),
multiboot_info_ptr->framebuffer_pitch,
multiboot_info_ptr->framebuffer_width,
multiboot_info_ptr->framebuffer_height);
} else {
new BXVGADevice;
}
}
LoopbackAdapter::the();
Process::initialize();
Thread::initialize();
Thread* init_stage2_thread = nullptr;
Process::create_kernel_process(init_stage2_thread, "init_stage2", init_stage2);
Thread* syncd_thread = nullptr;
Process::create_kernel_process(syncd_thread, "syncd", [] {
for (;;) {
VFS::the().sync();
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
2020-03-09 15:03:27 +00:00
Thread::current->sleep(1 * TimeManagement::the().ticks_per_second());
}
});
Process::create_kernel_process(g_finalizer, "Finalizer", [] {
Thread::current->set_priority(THREAD_PRIORITY_LOW);
for (;;) {
{
InterruptDisabler disabler;
if (!g_finalizer_has_work)
Thread::current->wait_on(*g_finalizer_wait_queue);
ASSERT(g_finalizer_has_work);
g_finalizer_has_work = false;
}
Thread::finalize_dying_threads();
}
});
Scheduler::pick_next();
sti();
Scheduler::idle_loop();
ASSERT_NOT_REACHED();
}
void init_stage2()
{
Syscall::initialize();
new ZeroDevice;
new FullDevice;
new RandomDevice;
new PTYMultiplexer;
bool dmi_unreliable = KParams::the().has("dmi_unreliable");
if (dmi_unreliable) {
DMIDecoder::initialize_untrusted();
} else {
DMIDecoder::initialize();
}
bool text_debug = KParams::the().has("text_debug");
bool force_pio = KParams::the().has("force_pio");
auto root = KParams::the().get("root");
if (root.is_empty()) {
root = "/dev/hda";
}
if (!root.starts_with("/dev/hda")) {
klog() << "init_stage2: root filesystem must be on the first IDE hard drive (/dev/hda)";
hang();
}
auto pata0 = PATAChannel::create(PATAChannel::ChannelType::Primary, force_pio);
NonnullRefPtr<BlockDevice> root_dev = *pata0->master_device();
root = root.substring(strlen("/dev/hda"), root.length() - strlen("/dev/hda"));
if (root.length()) {
bool ok;
unsigned partition_number = root.to_uint(ok);
if (!ok) {
klog() << "init_stage2: couldn't parse partition number from root kernel parameter";
hang();
}
MBRPartitionTable mbr(root_dev);
if (!mbr.initialize()) {
klog() << "init_stage2: couldn't read MBR from disk";
hang();
}
if (mbr.is_protective_mbr()) {
dbg() << "GPT Partitioned Storage Detected!";
GPTPartitionTable gpt(root_dev);
if (!gpt.initialize()) {
klog() << "init_stage2: couldn't read GPT from disk";
hang();
}
auto partition = gpt.partition(partition_number);
if (!partition) {
klog() << "init_stage2: couldn't get partition " << partition_number;
hang();
}
root_dev = *partition;
} else {
dbg() << "MBR Partitioned Storage Detected!";
if (mbr.contains_ebr()) {
EBRPartitionTable ebr(root_dev);
if (!ebr.initialize()) {
klog() << "init_stage2: couldn't read EBR from disk";
hang();
}
auto partition = ebr.partition(partition_number);
if (!partition) {
klog() << "init_stage2: couldn't get partition " << partition_number;
hang();
}
root_dev = *partition;
} else {
if (partition_number < 1 || partition_number > 4) {
klog() << "init_stage2: invalid partition number " << partition_number << "; expected 1 to 4";
hang();
}
auto partition = mbr.partition(partition_number);
if (!partition) {
klog() << "init_stage2: couldn't get partition " << partition_number;
hang();
}
root_dev = *partition;
}
}
}
auto e2fs = Ext2FS::create(*FileDescription::create(root_dev));
if (!e2fs->initialize()) {
klog() << "init_stage2: couldn't open root filesystem";
hang();
}
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if (!VFS::the().mount_root(e2fs)) {
klog() << "VFS::mount_root failed";
hang();
}
2018-10-17 09:44:06 +00:00
Process::current->set_root_directory(VFS::the().root_custody());
load_kernel_symbol_table();
int error;
// SystemServer will start WindowServer, which will be doing graphics.
// From this point on we don't want to touch the VGA text terminal or
// accept keyboard input.
if (text_debug) {
tty0->set_graphical(false);
Thread* thread = nullptr;
Process::create_user_process(thread, "/bin/Shell", (uid_t)0, (gid_t)0, (pid_t)0, error, {}, {}, tty0);
if (error != 0) {
klog() << "init_stage2: error spawning Shell: " << error;
hang();
}
thread->set_priority(THREAD_PRIORITY_HIGH);
} else {
tty0->set_graphical(true);
Thread* thread = nullptr;
Process::create_user_process(thread, "/bin/SystemServer", (uid_t)0, (gid_t)0, (pid_t)0, error, {}, {}, tty0);
if (error != 0) {
klog() << "init_stage2: error spawning SystemServer: " << error;
hang();
}
thread->set_priority(THREAD_PRIORITY_HIGH);
}
{
Thread* thread = nullptr;
Process::create_kernel_process(thread, "NetworkTask", NetworkTask_main);
}
Process::current->sys$exit(0);
ASSERT_NOT_REACHED();
}
void setup_serial_debug()
{
// this is only used one time, directly below here. we can't use this part
// of libc at this point in the boot process, or we'd just pull strstr in
// from <string.h>.
auto bad_prefix_check = [](const char* str, const char* search) -> bool {
while (*search)
if (*search++ != *str++)
return false;
return true;
};
// serial_debug will output all the klog() and dbg() data to COM1 at
// 8-N-1 57600 baud. this is particularly useful for debugging the boot
// process on live hardware.
//
// note: it must be the first option in the boot cmdline.
u32 cmdline = low_physical_to_virtual(multiboot_info_ptr->cmdline);
if (cmdline && bad_prefix_check(reinterpret_cast<const char*>(cmdline), "serial_debug"))
set_serial_debug(true);
}
extern "C" {
multiboot_info_t* multiboot_info_ptr;
}
// Define some Itanium C++ ABI methods to stop the linker from complaining
// If we actually call these something has gone horribly wrong
void* __dso_handle __attribute__((visibility("hidden")));
extern "C" int __cxa_atexit(void (*)(void*), void*, void*)
{
ASSERT_NOT_REACHED();
return 0;
}
void setup_acpi()
{
if (!KParams::the().has("acpi")) {
ACPI::DynamicParser::initialize_without_rsdp();
return;
}
auto acpi = KParams::the().get("acpi");
if (acpi == "off") {
ACPI::Parser::initialize_limited();
return;
}
if (acpi == "on") {
ACPI::DynamicParser::initialize_without_rsdp();
return;
}
if (acpi == "limited") {
ACPI::StaticParser::initialize_without_rsdp();
return;
}
klog() << "acpi boot argmuent has an invalid value.";
hang();
}
void setup_vmmouse()
{
VMWareBackdoor::initialize();
if (!KParams::the().has("vmmouse")) {
VMWareBackdoor::the().enable_absolute_vmmouse();
return;
}
auto vmmouse = KParams::the().get("vmmouse");
if (vmmouse == "off")
return;
if (vmmouse == "on") {
VMWareBackdoor::the().enable_absolute_vmmouse();
return;
}
klog() << "vmmouse boot argmuent has an invalid value.";
hang();
}
void setup_pci()
{
if (!KParams::the().has("pci_mmio")) {
PCI::Initializer::the().test_and_initialize(false);
PCI::Initializer::the().dismiss();
return;
}
auto pci_mmio = KParams::the().get("pci_mmio");
if (pci_mmio == "on") {
PCI::Initializer::the().test_and_initialize(false);
} else if (pci_mmio == "off") {
PCI::Initializer::the().test_and_initialize(true);
} else {
klog() << "pci_mmio boot argmuent has an invalid value.";
hang();
}
PCI::Initializer::the().dismiss();
}
void setup_interrupts()
{
InterruptManagement::initialize();
if (!KParams::the().has("smp")) {
InterruptManagement::the().switch_to_pic_mode();
return;
}
auto smp = KParams::the().get("smp");
if (smp == "off") {
InterruptManagement::the().switch_to_pic_mode();
return;
}
if (smp == "on") {
InterruptManagement::the().switch_to_ioapic_mode();
return;
}
klog() << "smp boot argmuent has an invalid value.";
hang();
}
Kernel: Introduce the new Time management subsystem This new subsystem includes better abstractions of how time will be handled in the OS. We take advantage of the existing RTC timer to aid in keeping time synchronized. This is standing in contrast to how we handled time-keeping in the kernel, where the PIT was responsible for that function in addition to update the scheduler about ticks. With that new advantage, we can easily change the ticking dynamically and still keep the time synchronized. In the process context, we no longer use a fixed declaration of TICKS_PER_SECOND, but we call the TimeManagement singleton class to provide us the right value. This allows us to use dynamic ticking in the future, a feature known as tickless kernel. The scheduler no longer does by himself the calculation of real time (Unix time), and just calls the TimeManagment singleton class to provide the value. Also, we can use 2 new boot arguments: - the "time" boot argument accpets either the value "modern", or "legacy". If "modern" is specified, the time management subsystem will try to setup HPET. Otherwise, for "legacy" value, the time subsystem will revert to use the PIT & RTC, leaving HPET disabled. If this boot argument is not specified, the default pattern is to try to setup HPET. - the "hpet" boot argumet accepts either the value "periodic" or "nonperiodic". If "periodic" is specified, the HPET will scan for periodic timers, and will assert if none are found. If only one is found, that timer will be assigned for the time-keeping task. If more than one is found, both time-keeping task & scheduler-ticking task will be assigned to periodic timers. If this boot argument is not specified, the default pattern is to try to scan for HPET periodic timers. This boot argument has no effect if HPET is disabled. In hardware context, PIT & RealTimeClock classes are merely inheriting from the HardwareTimer class, and they allow to use the old i8254 (PIT) and RTC devices, managing them via IO ports. By default, the RTC will be programmed to a frequency of 1024Hz. The PIT will be programmed to a frequency close to 1000Hz. About HPET, depending if we need to scan for periodic timers or not, we try to set a frequency close to 1000Hz for the time-keeping timer and scheduler-ticking timer. Also, if possible, we try to enable the Legacy replacement feature of the HPET. This feature if exists, instructs the chipset to disconnect both i8254 (PIT) and RTC. This behavior is observable on QEMU, and was verified against the source code: https://github.com/qemu/qemu/commit/ce967e2f33861b0e17753f97fa4527b5943c94b6 The HPETComparator class is inheriting from HardwareTimer class, and is responsible for an individual HPET comparator, which is essentially a timer. Therefore, it needs to call the singleton HPET class to perform HPET-related operations. The new abstraction of Hardware timers brings an opportunity of more new features in the foreseeable future. For example, we can change the callback function of each hardware timer, thus it makes it possible to swap missions between hardware timers, or to allow to use a hardware timer for other temporary missions (e.g. calibrating the LAPIC timer, measuring the CPU frequency, etc).
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void setup_time_management()
{
if (!KParams::the().has("time")) {
TimeManagement::initialize(true);
return;
}
auto time = KParams::the().get("time");
if (time == "legacy") {
TimeManagement::initialize(false);
return;
}
if (time == "modern") {
TimeManagement::initialize(true);
return;
}
kprintf("time boot argmuent has an invalid value.\n");
hang();
}
}