ladybird/Kernel/Lock.cpp
asynts 7cf0c7cc0d Meta: Split debug defines into multiple headers.
The following script was used to make these changes:

    #!/bin/bash
    set -e

    tmp=$(mktemp -d)

    echo "tmp=$tmp"

    find Kernel \( -name '*.cpp' -o -name '*.h' \) | sort > $tmp/Kernel.files
    find . \( -path ./Toolchain -prune -o -path ./Build -prune -o -path ./Kernel -prune \) -o \( -name '*.cpp' -o -name '*.h' \) -print | sort > $tmp/EverythingExceptKernel.files

    cat $tmp/Kernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/Kernel.macros
    cat $tmp/EverythingExceptKernel.files | xargs grep -Eho '[A-Z0-9_]+_DEBUG' | sort | uniq > $tmp/EverythingExceptKernel.macros

    comm -23 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/Kernel.unique
    comm -1 $tmp/Kernel.macros $tmp/EverythingExceptKernel.macros > $tmp/EverythingExceptKernel.unique

    cat $tmp/Kernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/Kernel.header
    cat $tmp/EverythingExceptKernel.unique | awk '{ print "#cmakedefine01 "$1 }' > $tmp/EverythingExceptKernel.header

    for macro in $(cat $tmp/Kernel.unique)
    do
        cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.new-includes ||:
    done
    cat $tmp/Kernel.new-includes | sort > $tmp/Kernel.new-includes.sorted

    for macro in $(cat $tmp/EverythingExceptKernel.unique)
    do
        cat $tmp/Kernel.files | xargs grep -l $macro >> $tmp/Kernel.old-includes ||:
    done
    cat $tmp/Kernel.old-includes | sort > $tmp/Kernel.old-includes.sorted

    comm -23 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.new
    comm -13 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.old
    comm -12 $tmp/Kernel.new-includes.sorted $tmp/Kernel.old-includes.sorted > $tmp/Kernel.includes.mixed

    for file in $(cat $tmp/Kernel.includes.new)
    do
        sed -i -E 's/#include <AK\/Debug\.h>/#include <Kernel\/Debug\.h>/' $file
    done

    for file in $(cat $tmp/Kernel.includes.mixed)
    do
        echo "mixed include in $file, requires manual editing."
    done
2021-01-26 21:20:00 +01:00

359 lines
14 KiB
C++

/*
* 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/TemporaryChange.h>
#include <Kernel/Debug.h>
#include <Kernel/KSyms.h>
#include <Kernel/Lock.h>
#include <Kernel/Thread.h>
namespace Kernel {
#if LOCK_DEBUG
void Lock::lock(Mode mode)
{
lock("unknown", 0, mode);
}
void Lock::lock(const char* file, int line, Mode mode)
#else
void Lock::lock(Mode mode)
#endif
{
// NOTE: This may be called from an interrupt handler (not an IRQ handler)
// and also from within critical sections!
ASSERT(!Processor::current().in_irq());
ASSERT(mode != Mode::Unlocked);
auto current_thread = Thread::current();
ScopedCritical critical; // in case we're not in a critical section already
for (;;) {
if (m_lock.exchange(true, AK::memory_order_acq_rel) != false) {
// I don't know *who* is using "m_lock", so just yield.
Scheduler::yield_from_critical();
continue;
}
// FIXME: Do not add new readers if writers are queued.
Mode current_mode = m_mode;
switch (current_mode) {
case Mode::Unlocked: {
dbgln<LOCK_TRACE_DEBUG>("Lock::lock @ ({}) {}: acquire {}, currently unlocked", this, m_name, mode_to_string(mode));
m_mode = mode;
ASSERT(!m_holder);
ASSERT(m_shared_holders.is_empty());
if (mode == Mode::Exclusive) {
m_holder = current_thread;
} else {
ASSERT(mode == Mode::Shared);
m_shared_holders.set(current_thread, 1);
}
ASSERT(m_times_locked == 0);
m_times_locked++;
#if LOCK_DEBUG
current_thread->holding_lock(*this, 1, file, line);
#endif
m_queue.should_block(true);
m_lock.store(false, AK::memory_order_release);
return;
}
case Mode::Exclusive: {
ASSERT(m_holder);
if (m_holder != current_thread)
break;
ASSERT(m_shared_holders.is_empty());
if constexpr (LOCK_TRACE_DEBUG) {
if (mode == Mode::Exclusive)
dbgln("Lock::lock @ {} ({}): acquire {}, currently exclusive, holding: {}", this, m_name, mode_to_string(mode), m_times_locked);
else
dbgln("Lock::lock @ {} ({}): acquire exclusive (requested {}), currently exclusive, holding: {}", this, m_name, mode_to_string(mode), m_times_locked);
}
ASSERT(mode == Mode::Exclusive || mode == Mode::Shared);
ASSERT(m_times_locked > 0);
m_times_locked++;
#if LOCK_DEBUG
current_thread->holding_lock(*this, 1, file, line);
#endif
m_lock.store(false, AK::memory_order_release);
return;
}
case Mode::Shared: {
ASSERT(!m_holder);
if (mode != Mode::Shared)
break;
dbgln<LOCK_TRACE_DEBUG>("Lock::lock @ {} ({}): acquire {}, currently shared, locks held {}", this, m_name, mode_to_string(mode), m_times_locked);
ASSERT(m_times_locked > 0);
m_times_locked++;
ASSERT(!m_shared_holders.is_empty());
auto it = m_shared_holders.find(current_thread);
if (it != m_shared_holders.end())
it->value++;
else
m_shared_holders.set(current_thread, 1);
#if LOCK_DEBUG
current_thread->holding_lock(*this, 1, file, line);
#endif
m_lock.store(false, AK::memory_order_release);
return;
}
default:
ASSERT_NOT_REACHED();
}
m_lock.store(false, AK::memory_order_release);
dbgln<LOCK_TRACE_DEBUG>("Lock::lock @ {} ({}) waiting...", this, m_name);
m_queue.wait_on({}, m_name);
dbgln<LOCK_TRACE_DEBUG>("Lock::lock @ {} ({}) waited", this, m_name);
}
}
void Lock::unlock()
{
// NOTE: This may be called from an interrupt handler (not an IRQ handler)
// and also from within critical sections!
ASSERT(!Processor::current().in_irq());
auto current_thread = Thread::current();
ScopedCritical critical; // in case we're not in a critical section already
for (;;) {
if (m_lock.exchange(true, AK::memory_order_acq_rel) == false) {
Mode current_mode = m_mode;
if constexpr (LOCK_TRACE_DEBUG) {
if (current_mode == Mode::Shared)
dbgln("Lock::unlock @ {} ({}): release {}, locks held: {}", this, m_name, mode_to_string(current_mode), m_times_locked);
else
dbgln("Lock::unlock @ {} ({}): release {}, holding: {}", this, m_name, mode_to_string(current_mode), m_times_locked);
}
ASSERT(current_mode != Mode::Unlocked);
ASSERT(m_times_locked > 0);
m_times_locked--;
switch (current_mode) {
case Mode::Exclusive:
ASSERT(m_holder == current_thread);
ASSERT(m_shared_holders.is_empty());
if (m_times_locked == 0)
m_holder = nullptr;
break;
case Mode::Shared: {
ASSERT(!m_holder);
auto it = m_shared_holders.find(current_thread);
ASSERT(it != m_shared_holders.end());
if (it->value > 1) {
it->value--;
} else {
ASSERT(it->value > 0);
m_shared_holders.remove(it);
}
break;
}
default:
ASSERT_NOT_REACHED();
}
bool unlocked_last = (m_times_locked == 0);
if (unlocked_last) {
ASSERT(current_mode == Mode::Exclusive ? !m_holder : m_shared_holders.is_empty());
m_mode = Mode::Unlocked;
m_queue.should_block(false);
}
#if LOCK_DEBUG
current_thread->holding_lock(*this, -1);
#endif
m_lock.store(false, AK::memory_order_release);
if (unlocked_last) {
u32 did_wake = m_queue.wake_one();
dbgln<LOCK_TRACE_DEBUG>("Lock::unlock @ {} ({}) wake one ({})", this, m_name, did_wake);
}
return;
}
// I don't know *who* is using "m_lock", so just yield.
Scheduler::yield_from_critical();
}
}
auto Lock::force_unlock_if_locked(u32& lock_count_to_restore) -> Mode
{
// NOTE: This may be called from an interrupt handler (not an IRQ handler)
// and also from within critical sections!
ASSERT(!Processor::current().in_irq());
auto current_thread = Thread::current();
ScopedCritical critical; // in case we're not in a critical section already
for (;;) {
if (m_lock.exchange(true, AK::memory_order_acq_rel) == false) {
Mode previous_mode;
auto current_mode = m_mode.load(AK::MemoryOrder::memory_order_relaxed);
switch (current_mode) {
case Mode::Exclusive: {
if (m_holder != current_thread) {
m_lock.store(false, AK::MemoryOrder::memory_order_release);
lock_count_to_restore = 0;
return Mode::Unlocked;
}
dbgln<LOCK_RESTORE_DEBUG>("Lock::force_unlock_if_locked @ {}: unlocking exclusive with lock count: {}", this, m_times_locked);
#if LOCK_DEBUG
m_holder->holding_lock(*this, -(int)lock_count_to_restore);
#endif
m_holder = nullptr;
ASSERT(m_times_locked > 0);
lock_count_to_restore = m_times_locked;
m_times_locked = 0;
m_mode = Mode::Unlocked;
m_queue.should_block(false);
m_lock.store(false, AK::memory_order_release);
previous_mode = Mode::Exclusive;
break;
}
case Mode::Shared: {
ASSERT(!m_holder);
auto it = m_shared_holders.find(current_thread);
if (it == m_shared_holders.end()) {
m_lock.store(false, AK::MemoryOrder::memory_order_release);
lock_count_to_restore = 0;
return Mode::Unlocked;
}
dbgln<LOCK_RESTORE_DEBUG>("Lock::force_unlock_if_locked @ {}: unlocking exclusive with lock count: {}, total locks: {}",
this, it->value, m_times_locked);
ASSERT(it->value > 0);
lock_count_to_restore = it->value;
ASSERT(lock_count_to_restore > 0);
#if LOCK_DEBUG
m_holder->holding_lock(*this, -(int)lock_count_to_restore);
#endif
m_shared_holders.remove(it);
ASSERT(m_times_locked >= lock_count_to_restore);
m_times_locked -= lock_count_to_restore;
if (m_times_locked == 0) {
m_mode = Mode::Unlocked;
m_queue.should_block(false);
}
m_lock.store(false, AK::memory_order_release);
previous_mode = Mode::Shared;
break;
}
case Mode::Unlocked: {
m_lock.store(false, AK::memory_order_relaxed);
lock_count_to_restore = 0;
previous_mode = Mode::Unlocked;
break;
}
default:
ASSERT_NOT_REACHED();
}
m_queue.wake_one();
return previous_mode;
}
// I don't know *who* is using "m_lock", so just yield.
Scheduler::yield_from_critical();
}
}
#if LOCK_DEBUG
void Lock::restore_lock(Mode mode, u32 lock_count)
{
return restore_lock("unknown", 0, mode, lock_count);
}
void Lock::restore_lock(const char* file, int line, Mode mode, u32 lock_count)
#else
void Lock::restore_lock(Mode mode, u32 lock_count)
#endif
{
ASSERT(mode != Mode::Unlocked);
ASSERT(lock_count > 0);
ASSERT(!Processor::current().in_irq());
auto current_thread = Thread::current();
ScopedCritical critical; // in case we're not in a critical section already
for (;;) {
if (m_lock.exchange(true, AK::memory_order_acq_rel) == false) {
switch (mode) {
case Mode::Exclusive: {
auto expected_mode = Mode::Unlocked;
if (!m_mode.compare_exchange_strong(expected_mode, Mode::Exclusive))
break;
dbgln<LOCK_RESTORE_DEBUG>("Lock::restore_lock @ {}: restoring {} with lock count {}, was unlocked", this, mode_to_string(mode), lock_count);
ASSERT(m_times_locked == 0);
m_times_locked = lock_count;
ASSERT(!m_holder);
ASSERT(m_shared_holders.is_empty());
m_holder = current_thread;
m_queue.should_block(true);
m_lock.store(false, AK::memory_order_release);
#if LOCK_DEBUG
m_holder->holding_lock(*this, (int)lock_count, file, line);
#endif
return;
}
case Mode::Shared: {
auto expected_mode = Mode::Unlocked;
if (!m_mode.compare_exchange_strong(expected_mode, Mode::Shared) && expected_mode != Mode::Shared)
break;
dbgln<LOCK_RESTORE_DEBUG>("Lock::restore_lock @ {}: restoring {} with lock count {}, was {}",
this, mode_to_string(mode), lock_count, mode_to_string(expected_mode));
ASSERT(expected_mode == Mode::Shared || m_times_locked == 0);
m_times_locked += lock_count;
ASSERT(!m_holder);
ASSERT((expected_mode == Mode::Unlocked) == m_shared_holders.is_empty());
auto set_result = m_shared_holders.set(current_thread, lock_count);
// There may be other shared lock holders already, but we should not have an entry yet
ASSERT(set_result == AK::HashSetResult::InsertedNewEntry);
m_queue.should_block(true);
m_lock.store(false, AK::memory_order_release);
#if LOCK_DEBUG
m_holder->holding_lock(*this, (int)lock_count, file, line);
#endif
return;
}
default:
ASSERT_NOT_REACHED();
}
m_lock.store(false, AK::memory_order_relaxed);
}
// I don't know *who* is using "m_lock", so just yield.
Scheduler::yield_from_critical();
}
}
void Lock::clear_waiters()
{
ASSERT(m_mode != Mode::Shared);
m_queue.wake_all();
}
}