LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-09-22 10:59:51 +03:00
Code Issues Packages Projects Releases Wiki Activity
a9f5b0339d
ladybird/Kernel/Thread.cpp
Luke 68b361bd21 Kernel: Return ENOMEM in more places 
There are plenty of places in the kernel that aren't
checking if they actually got their allocation.

This fixes some of them, but definitely not all.

Fixes #3390
Fixes #3391

Also, let's make find_one_free_page() return nullptr
if it doesn't get a free index. This stops the kernel
crashing when out of memory and allows memory purging
to take place again.

Fixes #3487
2020-09-16 20:38:19 +02:00

1097 lines
35 KiB
C++
Raw Blame History

/*
* 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 <AK/Demangle.h>
#include <AK/StringBuilder.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/FileSystem/FileDescription.h>
#include <Kernel/KSyms.h>
#include <Kernel/Process.h>
#include <Kernel/Profiling.h>
#include <Kernel/Scheduler.h>
#include <Kernel/Thread.h>
#include <Kernel/ThreadTracer.h>
#include <Kernel/TimerQueue.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/PageDirectory.h>
#include <Kernel/VM/ProcessPagingScope.h>
#include <LibC/signal_numbers.h>
#include <LibELF/Loader.h>
//#define SIGNAL_DEBUG
//#define THREAD_DEBUG
namespace Kernel {
Thread::Thread(NonnullRefPtr<Process> process)
: m_process(move(process))
, m_name(m_process->name())
{
if (m_process->m_thread_count.fetch_add(1, AK::MemoryOrder::memory_order_acq_rel) == 0) {
// First thread gets TID == PID
m_tid = m_process->pid().value();
} else {
m_tid = Process::allocate_pid().value();
}
#ifdef THREAD_DEBUG
dbg() << "Created new thread " << m_process->name() << "(" << m_process->pid().value() << ":" << m_tid.value() << ")";
#endif
set_default_signal_dispositions();
m_fpu_state = (FPUState*)kmalloc_aligned<16>(sizeof(FPUState));
reset_fpu_state();
memset(&m_tss, 0, sizeof(m_tss));
m_tss.iomapbase = sizeof(TSS32);
// Only IF is set when a process boots.
m_tss.eflags = 0x0202;
if (m_process->is_kernel_process()) {
m_tss.cs = GDT_SELECTOR_CODE0;
m_tss.ds = GDT_SELECTOR_DATA0;
m_tss.es = GDT_SELECTOR_DATA0;
m_tss.fs = GDT_SELECTOR_PROC;
m_tss.ss = GDT_SELECTOR_DATA0;
m_tss.gs = 0;
} else {
m_tss.cs = GDT_SELECTOR_CODE3 | 3;
m_tss.ds = GDT_SELECTOR_DATA3 | 3;
m_tss.es = GDT_SELECTOR_DATA3 | 3;
m_tss.fs = GDT_SELECTOR_DATA3 | 3;
m_tss.ss = GDT_SELECTOR_DATA3 | 3;
m_tss.gs = GDT_SELECTOR_TLS | 3;
}
m_tss.cr3 = m_process->page_directory().cr3();
m_kernel_stack_region = MM.allocate_kernel_region(default_kernel_stack_size, String::format("Kernel Stack (Thread %d)", m_tid.value()), Region::Access::Read | Region::Access::Write, false, true);
m_kernel_stack_region->set_stack(true);
m_kernel_stack_base = m_kernel_stack_region->vaddr().get();
m_kernel_stack_top = m_kernel_stack_region->vaddr().offset(default_kernel_stack_size).get() & 0xfffffff8u;
if (m_process->is_kernel_process()) {
m_tss.esp = m_tss.esp0 = m_kernel_stack_top;
} else {
// Ring 3 processes get a separate stack for ring 0.
// The ring 3 stack will be assigned by exec().
m_tss.ss0 = GDT_SELECTOR_DATA0;
m_tss.esp0 = m_kernel_stack_top;
}
if (m_process->pid() != 0)
Scheduler::init_thread(*this);
}
Thread::~Thread()
{
kfree_aligned(m_fpu_state);
auto thread_cnt_before = m_process->m_thread_count.fetch_sub(1, AK::MemoryOrder::memory_order_acq_rel);
ASSERT(thread_cnt_before != 0);
}
void Thread::unblock()
{
ASSERT(m_lock.own_lock());
m_blocker = nullptr;
if (Thread::current() == this) {
set_state(Thread::Running);
return;
}
ASSERT(m_state != Thread::Runnable && m_state != Thread::Running);
set_state(Thread::Runnable);
}
void Thread::set_should_die()
{
if (m_should_die) {
#ifdef THREAD_DEBUG
dbg() << *this << " Should already die";
#endif
return;
}
ScopedCritical critical;
// Remember that we should die instead of returning to
// the userspace.
{
ScopedSpinLock lock(g_scheduler_lock);
m_should_die = true;
// NOTE: Even the current thread can technically be in "Stopped"
// state! This is the case when another thread sent a SIGSTOP to
// it while it was running and it calls e.g. exit() before
// the scheduler gets involved again.
if (is_stopped()) {
// If we were stopped, we need to briefly resume so that
// the kernel stacks can clean up. We won't ever return back
// to user mode, though
resume_from_stopped();
}
}
if (is_blocked()) {
ScopedSpinLock lock(m_lock);
ASSERT(m_blocker != nullptr);
// We're blocked in the kernel.
m_blocker->set_interrupted_by_death();
unblock();
}
}
void Thread::die_if_needed()
{
ASSERT(Thread::current() == this);
if (!m_should_die)
return;
unlock_process_if_locked();
ScopedCritical critical;
set_should_die();
// Flag a context switch. Because we're in a critical section,
// Scheduler::yield will actually only mark a pending scontext switch
// Simply leaving the critical section would not necessarily trigger
// a switch.
Scheduler::yield();
// Now leave the critical section so that we can also trigger the
// actual context switch
u32 prev_flags;
Processor::current().clear_critical(prev_flags, false);
dbg() << "die_if_needed returned form clear_critical!!! in irq: " << Processor::current().in_irq();
// We should never get here, but the scoped scheduler lock
// will be released by Scheduler::context_switch again
ASSERT_NOT_REACHED();
}
void Thread::yield_without_holding_big_lock()
{
bool did_unlock = unlock_process_if_locked();
Scheduler::yield();
relock_process(did_unlock);
}
bool Thread::unlock_process_if_locked()
{
return process().big_lock().force_unlock_if_locked();
}
void Thread::relock_process(bool did_unlock)
{
if (did_unlock)
process().big_lock().lock();
}
u64 Thread::sleep(u64 ticks)
{
ASSERT(state() == Thread::Running);
u64 wakeup_time = g_uptime + ticks;
auto ret = Thread::current()->block<Thread::SleepBlocker>(nullptr, wakeup_time);
if (wakeup_time > g_uptime) {
ASSERT(ret.was_interrupted());
}
return wakeup_time;
}
u64 Thread::sleep_until(u64 wakeup_time)
{
ASSERT(state() == Thread::Running);
auto ret = Thread::current()->block<Thread::SleepBlocker>(nullptr, wakeup_time);
if (wakeup_time > g_uptime)
ASSERT(ret.was_interrupted());
return wakeup_time;
}
const char* Thread::state_string() const
{
switch (state()) {
case Thread::Invalid:
return "Invalid";
case Thread::Runnable:
return "Runnable";
case Thread::Running:
return "Running";
case Thread::Dying:
return "Dying";
case Thread::Dead:
return "Dead";
case Thread::Stopped:
return "Stopped";
case Thread::Queued:
return "Queued";
case Thread::Blocked:
ASSERT(m_blocker != nullptr);
return m_blocker->state_string();
}
klog() << "Thread::state_string(): Invalid state: " << state();
ASSERT_NOT_REACHED();
return nullptr;
}
void Thread::finalize()
{
ASSERT(Thread::current() == g_finalizer);
ASSERT(Thread::current() != this);
#ifdef THREAD_DEBUG
dbg() << "Finalizing thread " << *this;
#endif
set_state(Thread::State::Dead);
if (m_joiner) {
ScopedSpinLock lock(m_joiner->m_lock);
ASSERT(m_joiner->m_joinee == this);
static_cast<JoinBlocker*>(m_joiner->m_blocker)->set_joinee_exit_value(m_exit_value);
static_cast<JoinBlocker*>(m_joiner->m_blocker)->set_interrupted_by_death();
m_joiner->m_joinee = nullptr;
// NOTE: We clear the joiner pointer here as well, to be tidy.
m_joiner = nullptr;
}
if (m_dump_backtrace_on_finalization)
dbg() << backtrace_impl();
}
void Thread::finalize_dying_threads()
{
ASSERT(Thread::current() == g_finalizer);
Vector<Thread*, 32> dying_threads;
{
ScopedSpinLock lock(g_scheduler_lock);
for_each_in_state(Thread::State::Dying, [&](Thread& thread) {
if (thread.is_finalizable())
dying_threads.append(&thread);
return IterationDecision::Continue;
});
}
for (auto* thread : dying_threads) {
auto& process = thread->process();
thread->finalize();
delete thread;
if (process.m_thread_count.load(AK::MemoryOrder::memory_order_consume) == 0)
process.finalize();
}
}
bool Thread::tick()
{
++m_ticks;
if (tss().cs & 3)
++m_process->m_ticks_in_user;
else
++m_process->m_ticks_in_kernel;
return --m_ticks_left;
}
bool Thread::has_pending_signal(u8 signal) const
{
ScopedSpinLock lock(g_scheduler_lock);
return m_pending_signals & (1 << (signal - 1));
}
u32 Thread::pending_signals() const
{
ScopedSpinLock lock(g_scheduler_lock);
return m_pending_signals;
}
void Thread::send_signal(u8 signal, [[maybe_unused]] Process* sender)
{
ASSERT(signal < 32);
ScopedSpinLock lock(g_scheduler_lock);
// FIXME: Figure out what to do for masked signals. Should we also ignore them here?
if (should_ignore_signal(signal)) {
#ifdef SIGNAL_DEBUG
dbg() << "Signal " << signal << " was ignored by " << process();
#endif
return;
}
#ifdef SIGNAL_DEBUG
if (sender)
dbg() << "Signal: " << *sender << " sent " << signal << " to " << process();
else
dbg() << "Signal: Kernel sent " << signal << " to " << process();
#endif
m_pending_signals |= 1 << (signal - 1);
m_have_any_unmasked_pending_signals.store(m_pending_signals & ~m_signal_mask, AK::memory_order_release);
}
u32 Thread::update_signal_mask(u32 signal_mask)
{
ScopedSpinLock lock(g_scheduler_lock);
auto previous_signal_mask = m_signal_mask;
m_signal_mask = signal_mask;
m_have_any_unmasked_pending_signals.store(m_pending_signals & ~m_signal_mask, AK::memory_order_release);
return previous_signal_mask;
}
u32 Thread::signal_mask() const
{
ScopedSpinLock lock(g_scheduler_lock);
return m_signal_mask;
}
u32 Thread::signal_mask_block(sigset_t signal_set, bool block)
{
ScopedSpinLock lock(g_scheduler_lock);
auto previous_signal_mask = m_signal_mask;
if (block)
m_signal_mask &= ~signal_set;
else
m_signal_mask |= signal_set;
m_have_any_unmasked_pending_signals.store(m_pending_signals & ~m_signal_mask, AK::memory_order_release);
return previous_signal_mask;
}
void Thread::clear_signals()
{
ScopedSpinLock lock(g_scheduler_lock);
m_signal_mask = 0;
m_pending_signals = 0;
m_have_any_unmasked_pending_signals.store(false, AK::memory_order_release);
}
// Certain exceptions, such as SIGSEGV and SIGILL, put a
// thread into a state where the signal handler must be
// invoked immediately, otherwise it will continue to fault.
// This function should be used in an exception handler to
// ensure that when the thread resumes, it's executing in
// the appropriate signal handler.
void Thread::send_urgent_signal_to_self(u8 signal)
{
ASSERT(Thread::current() == this);
ScopedSpinLock lock(g_scheduler_lock);
if (dispatch_signal(signal) == ShouldUnblockThread::No)
Scheduler::yield();
}
ShouldUnblockThread Thread::dispatch_one_pending_signal()
{
ASSERT(m_lock.own_lock());
u32 signal_candidates = m_pending_signals & ~m_signal_mask;
ASSERT(signal_candidates);
u8 signal = 1;
for (; signal < 32; ++signal) {
if (signal_candidates & (1 << (signal - 1))) {
break;
}
}
return dispatch_signal(signal);
}
enum class DefaultSignalAction {
Terminate,
Ignore,
DumpCore,
Stop,
Continue,
};
static DefaultSignalAction default_signal_action(u8 signal)
{
ASSERT(signal && signal < NSIG);
switch (signal) {
case SIGHUP:
case SIGINT:
case SIGKILL:
case SIGPIPE:
case SIGALRM:
case SIGUSR1:
case SIGUSR2:
case SIGVTALRM:
case SIGSTKFLT:
case SIGIO:
case SIGPROF:
case SIGTERM:
return DefaultSignalAction::Terminate;
case SIGCHLD:
case SIGURG:
case SIGWINCH:
case SIGINFO:
return DefaultSignalAction::Ignore;
case SIGQUIT:
case SIGILL:
case SIGTRAP:
case SIGABRT:
case SIGBUS:
case SIGFPE:
case SIGSEGV:
case SIGXCPU:
case SIGXFSZ:
case SIGSYS:
return DefaultSignalAction::DumpCore;
case SIGCONT:
return DefaultSignalAction::Continue;
case SIGSTOP:
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
return DefaultSignalAction::Stop;
}
ASSERT_NOT_REACHED();
}
bool Thread::should_ignore_signal(u8 signal) const
{
ASSERT(signal < 32);
auto& action = m_signal_action_data[signal];
if (action.handler_or_sigaction.is_null())
return default_signal_action(signal) == DefaultSignalAction::Ignore;
if (action.handler_or_sigaction.as_ptr() == SIG_IGN)
return true;
return false;
}
bool Thread::has_signal_handler(u8 signal) const
{
ASSERT(signal < 32);
auto& action = m_signal_action_data[signal];
return !action.handler_or_sigaction.is_null();
}
static bool push_value_on_user_stack(u32* stack, u32 data)
{
*stack -= 4;
return copy_to_user((u32*)*stack, &data);
}
void Thread::resume_from_stopped()
{
ASSERT(is_stopped());
ASSERT(m_stop_state != State::Invalid);
set_state(m_stop_state);
m_stop_state = State::Invalid;
// make sure SemiPermanentBlocker is unblocked
if (m_state != Thread::Runnable && m_state != Thread::Running) {
ScopedSpinLock lock(m_lock);
if (m_blocker && m_blocker->is_reason_signal())
unblock();
}
}
ShouldUnblockThread Thread::dispatch_signal(u8 signal)
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(g_scheduler_lock.own_lock());
ASSERT(signal > 0 && signal <= 32);
ASSERT(process().is_user_process());
#ifdef SIGNAL_DEBUG
klog() << "signal: dispatch signal " << signal << " to " << *this;
#endif
if (m_state == Invalid || !is_initialized()) {
// Thread has barely been created, we need to wait until it is
// at least in Runnable state and is_initialized() returns true,
// which indicates that it is fully set up an we actually have
// a register state on the stack that we can modify
return ShouldUnblockThread::No;
}
auto& action = m_signal_action_data[signal];
// FIXME: Implement SA_SIGINFO signal handlers.
ASSERT(!(action.flags & SA_SIGINFO));
// Mark this signal as handled.
m_pending_signals &= ~(1 << (signal - 1));
m_have_any_unmasked_pending_signals.store(m_pending_signals & ~m_signal_mask, AK::memory_order_release);
if (signal == SIGSTOP) {
if (!is_stopped()) {
m_stop_signal = SIGSTOP;
set_state(State::Stopped);
}
return ShouldUnblockThread::No;
}
if (signal == SIGCONT && is_stopped()) {
resume_from_stopped();
} else {
auto* thread_tracer = tracer();
if (thread_tracer != nullptr) {
// when a thread is traced, it should be stopped whenever it receives a signal
// the tracer is notified of this by using waitpid()
// only "pending signals" from the tracer are sent to the tracee
if (!thread_tracer->has_pending_signal(signal)) {
m_stop_signal = signal;
// make sure SemiPermanentBlocker is unblocked
ScopedSpinLock lock(m_lock);
if (m_blocker && m_blocker->is_reason_signal())
unblock();
set_state(Stopped);
return ShouldUnblockThread::No;
}
thread_tracer->unset_signal(signal);
}
}
auto handler_vaddr = action.handler_or_sigaction;
if (handler_vaddr.is_null()) {
switch (default_signal_action(signal)) {
case DefaultSignalAction::Stop:
m_stop_signal = signal;
set_state(Stopped);
return ShouldUnblockThread::No;
case DefaultSignalAction::DumpCore:
process().for_each_thread([](auto& thread) {
thread.set_dump_backtrace_on_finalization();
return IterationDecision::Continue;
});
[[fallthrough]];
case DefaultSignalAction::Terminate:
m_process->terminate_due_to_signal(signal);
return ShouldUnblockThread::No;
case DefaultSignalAction::Ignore:
ASSERT_NOT_REACHED();
case DefaultSignalAction::Continue:
return ShouldUnblockThread::Yes;
}
ASSERT_NOT_REACHED();
}
if (handler_vaddr.as_ptr() == SIG_IGN) {
#ifdef SIGNAL_DEBUG
klog() << "signal: " << *this << " ignored signal " << signal;
#endif
return ShouldUnblockThread::Yes;
}
ProcessPagingScope paging_scope(m_process);
u32 old_signal_mask = m_signal_mask;
u32 new_signal_mask = action.mask;
if (action.flags & SA_NODEFER)
new_signal_mask &= ~(1 << (signal - 1));
else
new_signal_mask |= 1 << (signal - 1);
m_signal_mask |= new_signal_mask;
m_have_any_unmasked_pending_signals.store(m_pending_signals & ~m_signal_mask, AK::memory_order_release);
auto setup_stack = [&](RegisterState& state) {
u32* stack = &state.userspace_esp;
u32 old_esp = *stack;
u32 ret_eip = state.eip;
u32 ret_eflags = state.eflags;
#ifdef SIGNAL_DEBUG
klog() << "signal: setting up user stack to return to eip: " << String::format("%p", ret_eip) << " esp: " << String::format("%p", old_esp);
#endif
// Align the stack to 16 bytes.
// Note that we push 56 bytes (4 * 14) on to the stack,
// so we need to account for this here.
u32 stack_alignment = (*stack - 56) % 16;
*stack -= stack_alignment;
push_value_on_user_stack(stack, ret_eflags);
push_value_on_user_stack(stack, ret_eip);
push_value_on_user_stack(stack, state.eax);
push_value_on_user_stack(stack, state.ecx);
push_value_on_user_stack(stack, state.edx);
push_value_on_user_stack(stack, state.ebx);
push_value_on_user_stack(stack, old_esp);
push_value_on_user_stack(stack, state.ebp);
push_value_on_user_stack(stack, state.esi);
push_value_on_user_stack(stack, state.edi);
// PUSH old_signal_mask
push_value_on_user_stack(stack, old_signal_mask);
push_value_on_user_stack(stack, signal);
push_value_on_user_stack(stack, handler_vaddr.get());
push_value_on_user_stack(stack, 0); //push fake return address
ASSERT((*stack % 16) == 0);
};
// We now place the thread state on the userspace stack.
// Note that we use a RegisterState.
// Conversely, when the thread isn't blocking the RegisterState may not be
// valid (fork, exec etc) but the tss will, so we use that instead.
auto& regs = get_register_dump_from_stack();
setup_stack(regs);
regs.eip = g_return_to_ring3_from_signal_trampoline.get();
#ifdef SIGNAL_DEBUG
klog() << "signal: Okay, " << *this << " {" << state_string() << "} has been primed with signal handler " << String::format("%w", m_tss.cs) << ":" << String::format("%x", m_tss.eip) << " to deliver " << signal;
#endif
return ShouldUnblockThread::Yes;
}
void Thread::set_default_signal_dispositions()
{
// FIXME: Set up all the right default actions. See signal(7).
memset(&m_signal_action_data, 0, sizeof(m_signal_action_data));
m_signal_action_data[SIGCHLD].handler_or_sigaction = VirtualAddress(SIG_IGN);
m_signal_action_data[SIGWINCH].handler_or_sigaction = VirtualAddress(SIG_IGN);
}
bool Thread::push_value_on_stack(FlatPtr value)
{
m_tss.esp -= 4;
FlatPtr* stack_ptr = (FlatPtr*)m_tss.esp;
return copy_to_user(stack_ptr, &value);
}
RegisterState& Thread::get_register_dump_from_stack()
{
return *(RegisterState*)(kernel_stack_top() - sizeof(RegisterState));
}
KResultOr<u32> Thread::make_userspace_stack_for_main_thread(Vector<String> arguments, Vector<String> environment, Vector<AuxiliaryValue> auxiliary_values)
{
auto* region = m_process->allocate_region(VirtualAddress(), default_userspace_stack_size, "Stack (Main thread)", PROT_READ | PROT_WRITE, false);
if (!region)
return KResult(-ENOMEM);
region->set_stack(true);
FlatPtr new_esp = region->vaddr().offset(default_userspace_stack_size).get();
auto push_on_new_stack = [&new_esp](u32 value) {
new_esp -= 4;
Userspace<u32*> stack_ptr = new_esp;
return copy_to_user(stack_ptr, &value);
};
auto push_aux_value_on_new_stack = [&new_esp](auxv_t value) {
new_esp -= sizeof(auxv_t);
Userspace<auxv_t*> stack_ptr = new_esp;
return copy_to_user(stack_ptr, &value);
};
auto push_string_on_new_stack = [&new_esp](const String& string) {
new_esp -= round_up_to_power_of_two(string.length() + 1, 4);
Userspace<u32*> stack_ptr = new_esp;
return copy_to_user(stack_ptr, string.characters(), string.length() + 1);
};
Vector<FlatPtr> argv_entries;
for (auto& argument : arguments) {
push_string_on_new_stack(argument);
argv_entries.append(new_esp);
}
Vector<FlatPtr> env_entries;
for (auto& variable : environment) {
push_string_on_new_stack(variable);
env_entries.append(new_esp);
}
for (auto& value : auxiliary_values) {
if (!value.optional_string.is_empty()) {
push_string_on_new_stack(value.optional_string);
value.auxv.a_un.a_ptr = (void*)new_esp;
}
}
for (ssize_t i = auxiliary_values.size() - 1; i >= 0; --i) {
auto& value = auxiliary_values[i];
push_aux_value_on_new_stack(value.auxv);
}
push_on_new_stack(0);
for (ssize_t i = env_entries.size() - 1; i >= 0; --i)
push_on_new_stack(env_entries[i]);
FlatPtr envp = new_esp;
push_on_new_stack(0);
for (ssize_t i = argv_entries.size() - 1; i >= 0; --i)
push_on_new_stack(argv_entries[i]);
FlatPtr argv = new_esp;
// NOTE: The stack needs to be 16-byte aligned.
new_esp -= new_esp % 16;
push_on_new_stack((FlatPtr)envp);
push_on_new_stack((FlatPtr)argv);
push_on_new_stack((FlatPtr)argv_entries.size());
push_on_new_stack(0);
return new_esp;
}
Thread* Thread::clone(Process& process)
{
auto* clone = new Thread(process);
memcpy(clone->m_signal_action_data, m_signal_action_data, sizeof(m_signal_action_data));
clone->m_signal_mask = m_signal_mask;
memcpy(clone->m_fpu_state, m_fpu_state, sizeof(FPUState));
clone->m_thread_specific_data = m_thread_specific_data;
clone->m_thread_specific_region_size = m_thread_specific_region_size;
return clone;
}
void Thread::set_state(State new_state)
{
ScopedSpinLock lock(g_scheduler_lock);
if (new_state == m_state)
return;
if (new_state == Blocked) {
// we should always have a Blocker while blocked
ASSERT(m_blocker != nullptr);
}
auto previous_state = m_state;
if (previous_state == Invalid) {
// If we were *just* created, we may have already pending signals
ScopedSpinLock thread_lock(m_lock);
if (has_unmasked_pending_signals()) {
dbg() << "Dispatch pending signals to new thread " << *this;
dispatch_one_pending_signal();
}
}
if (new_state == Stopped) {
m_stop_state = m_state;
}
m_state = new_state;
#ifdef THREAD_DEBUG
dbg() << "Set Thread " << *this << " state to " << state_string();
#endif
if (m_process->pid() != 0) {
update_state_for_thread(previous_state);
ASSERT(g_scheduler_data->has_thread(*this));
}
if (m_state == Dying) {
ASSERT(previous_state != Queued);
if (this != Thread::current() && is_finalizable()) {
// Some other thread set this thread to Dying, notify the
// finalizer right away as it can be cleaned up now
Scheduler::notify_finalizer();
}
}
}
void Thread::update_state_for_thread(Thread::State previous_state)
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(g_scheduler_data);
ASSERT(g_scheduler_lock.own_lock());
auto& previous_list = g_scheduler_data->thread_list_for_state(previous_state);
auto& list = g_scheduler_data->thread_list_for_state(state());
if (&previous_list != &list) {
previous_list.remove(*this);
}
if (list.contains(*this))
return;
list.append(*this);
}
String Thread::backtrace()
{
return backtrace_impl();
}
struct RecognizedSymbol {
u32 address;
const KernelSymbol* symbol { nullptr };
};
static bool symbolicate(const RecognizedSymbol& symbol, const Process& process, StringBuilder& builder, Process::ELFBundle* elf_bundle)
{
if (!symbol.address)
return false;
bool mask_kernel_addresses = !process.is_superuser();
if (!symbol.symbol) {
if (!is_user_address(VirtualAddress(symbol.address))) {
builder.append("0xdeadc0de\n");
} else {
if (elf_bundle && elf_bundle->elf_loader->has_symbols())
builder.appendf("%p %s\n", symbol.address, elf_bundle->elf_loader->symbolicate(symbol.address).characters());
else
builder.appendf("%p\n", symbol.address);
}
return true;
}
unsigned offset = symbol.address - symbol.symbol->address;
if (symbol.symbol->address == g_highest_kernel_symbol_address && offset > 4096) {
builder.appendf("%p\n", mask_kernel_addresses ? 0xdeadc0de : symbol.address);
} else {
builder.appendf("%p %s +%u\n", mask_kernel_addresses ? 0xdeadc0de : symbol.address, demangle(symbol.symbol->name).characters(), offset);
}
return true;
}
String Thread::backtrace_impl()
{
Vector<RecognizedSymbol, 128> recognized_symbols;
auto& process = const_cast<Process&>(this->process());
OwnPtr<Process::ELFBundle> elf_bundle;
if (!Processor::current().in_irq()) {
// If we're handling IRQs we can't really safely symbolicate
elf_bundle = process.elf_bundle();
}
ProcessPagingScope paging_scope(process);
// To prevent a context switch involving this thread, which may happen
// on another processor, we need to acquire the scheduler lock while
// walking the stack
{
ScopedSpinLock lock(g_scheduler_lock);
FlatPtr stack_ptr, eip;
if (Processor::get_context_frame_ptr(*this, stack_ptr, eip)) {
recognized_symbols.append({ eip, symbolicate_kernel_address(eip) });
while (stack_ptr) {
FlatPtr retaddr;
if (is_user_range(VirtualAddress(stack_ptr), sizeof(FlatPtr) * 2)) {
if (!copy_from_user(&retaddr, &((FlatPtr*)stack_ptr)[1]))
break;
recognized_symbols.append({ retaddr, symbolicate_kernel_address(retaddr) });
if (!copy_from_user(&stack_ptr, (FlatPtr*)stack_ptr))
break;
} else {
void* fault_at;
if (!safe_memcpy(&retaddr, &((FlatPtr*)stack_ptr)[1], sizeof(FlatPtr), fault_at))
break;
recognized_symbols.append({ retaddr, symbolicate_kernel_address(retaddr) });
if (!safe_memcpy(&stack_ptr, (FlatPtr*)stack_ptr, sizeof(FlatPtr), fault_at))
break;
}
}
}
}
StringBuilder builder;
for (auto& symbol : recognized_symbols) {
if (!symbolicate(symbol, process, builder, elf_bundle.ptr()))
break;
}
return builder.to_string();
}
Vector<FlatPtr> Thread::raw_backtrace(FlatPtr ebp, FlatPtr eip) const
{
InterruptDisabler disabler;
auto& process = const_cast<Process&>(this->process());
ProcessPagingScope paging_scope(process);
Vector<FlatPtr, Profiling::max_stack_frame_count> backtrace;
backtrace.append(eip);
FlatPtr stack_ptr_copy;
FlatPtr stack_ptr = (FlatPtr)ebp;
while (stack_ptr) {
void* fault_at;
if (!safe_memcpy(&stack_ptr_copy, (void*)stack_ptr, sizeof(FlatPtr), fault_at))
break;
FlatPtr retaddr;
if (!safe_memcpy(&retaddr, (void*)(stack_ptr + sizeof(FlatPtr)), sizeof(FlatPtr), fault_at))
break;
backtrace.append(retaddr);
if (backtrace.size() == Profiling::max_stack_frame_count)
break;
stack_ptr = stack_ptr_copy;
}
return backtrace;
}
KResult Thread::make_thread_specific_region(Badge<Process>)
{
size_t thread_specific_region_alignment = max(process().m_master_tls_alignment, alignof(ThreadSpecificData));
m_thread_specific_region_size = align_up_to(process().m_master_tls_size, thread_specific_region_alignment) + sizeof(ThreadSpecificData);
auto* region = process().allocate_region({}, m_thread_specific_region_size, "Thread-specific", PROT_READ | PROT_WRITE, true);
if (!region)
return KResult(-ENOMEM);
SmapDisabler disabler;
auto* thread_specific_data = (ThreadSpecificData*)region->vaddr().offset(align_up_to(process().m_master_tls_size, thread_specific_region_alignment)).as_ptr();
auto* thread_local_storage = (u8*)((u8*)thread_specific_data) - align_up_to(process().m_master_tls_size, process().m_master_tls_alignment);
m_thread_specific_data = VirtualAddress(thread_specific_data);
thread_specific_data->self = thread_specific_data;
if (process().m_master_tls_size)
memcpy(thread_local_storage, process().m_master_tls_region->vaddr().as_ptr(), process().m_master_tls_size);
return KSuccess;
}
const LogStream& operator<<(const LogStream& stream, const Thread& value)
{
return stream << value.process().name() << "(" << value.pid().value() << ":" << value.tid().value() << ")";
}
Thread::BlockResult Thread::wait_on(WaitQueue& queue, const char* reason, timeval* timeout, Atomic<bool>* lock, Thread* beneficiary)
{
auto* current_thread = Thread::current();
TimerId timer_id {};
bool did_unlock;
{
ScopedCritical critical;
// We need to be in a critical section *and* then also acquire the
// scheduler lock. The only way acquiring the scheduler lock could
// block us is if another core were to be holding it, in which case
// we need to wait until the scheduler lock is released again
{
ScopedSpinLock sched_lock(g_scheduler_lock);
if (!queue.enqueue(*current_thread)) {
// The WaitQueue was already requested to wake someone when
// nobody was waiting. So return right away as we shouldn't
// be waiting
// The API contract guarantees we return with interrupts enabled,
// regardless of how we got called
critical.set_interrupt_flag_on_destruction(true);
return BlockResult::NotBlocked;
}
did_unlock = unlock_process_if_locked();
if (lock)
*lock = false;
set_state(State::Queued);
m_wait_reason = reason;
if (timeout) {
timer_id = TimerQueue::the().add_timer(*timeout, [&]() {
wake_from_queue();
});
}
// Yield and wait for the queue to wake us up again.
if (beneficiary)
Scheduler::donate_to(beneficiary, reason);
else
Scheduler::yield();
}
// Clearing the critical section may trigger the context switch
// flagged by calling Scheduler::donate_to or Scheduler::yield
// above. We have to do it this way because we intentionally
// leave the critical section here to be able to switch contexts.
u32 prev_flags;
u32 prev_crit = Processor::current().clear_critical(prev_flags, true);
// We've unblocked, relock the process if needed and carry on.
relock_process(did_unlock);
// NOTE: We may be on a differenct CPU now!
Processor::current().restore_critical(prev_crit, prev_flags);
// This looks counter productive, but we may not actually leave
// the critical section we just restored. It depends on whether
// we were in one while being called.
if (current_thread->should_die()) {
// We're being unblocked so that we can clean up. We shouldn't
// be in Dying state until we're about to return back to user mode
ASSERT(current_thread->state() == Thread::Running);
#ifdef THREAD_DEBUG
dbg() << "Dying thread " << *current_thread << " was unblocked";
#endif
}
}
BlockResult result(BlockResult::WokeNormally);
{
// To be able to look at m_wait_queue_node we once again need the
// scheduler lock, which is held when we insert into the queue
ScopedSpinLock sched_lock(g_scheduler_lock);
// If our thread was still in the queue, we timed out
if (queue.dequeue(*current_thread))
result = BlockResult::InterruptedByTimeout;
// Make sure we cancel the timer if woke normally.
if (timeout && !result.was_interrupted())
TimerQueue::the().cancel_timer(timer_id);
}
// The API contract guarantees we return with interrupts enabled,
// regardless of how we got called
sti();
return result;
}
void Thread::wake_from_queue()
{
ScopedSpinLock lock(g_scheduler_lock);
ASSERT(state() == State::Queued);
m_wait_reason = nullptr;
if (this != Thread::current())
set_state(State::Runnable);
else
set_state(State::Running);
}
Thread* Thread::from_tid(ThreadID tid)
{
InterruptDisabler disabler;
Thread* found_thread = nullptr;
Thread::for_each([&](auto& thread) {
if (thread.tid() == tid) {
found_thread = &thread;
return IterationDecision::Break;
}
return IterationDecision::Continue;
});
return found_thread;
}
void Thread::reset_fpu_state()
{
memcpy(m_fpu_state, &Processor::current().clean_fpu_state(), sizeof(FPUState));
}
void Thread::start_tracing_from(ProcessID tracer)
{
m_tracer = ThreadTracer::create(tracer);
}
void Thread::stop_tracing()
{
m_tracer = nullptr;
}
void Thread::tracer_trap(const RegisterState& regs)
{
ASSERT(m_tracer.ptr());
m_tracer->set_regs(regs);
send_urgent_signal_to_self(SIGTRAP);
}
const Thread::Blocker& Thread::blocker() const
{
ASSERT(m_blocker);
return *m_blocker;
}
}
Reference in New Issue View Git Blame Copy Permalink