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https://github.com/LadybirdBrowser/ladybird.git
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da5cc34ebb
Fix some problems with join blocks where the joining thread block condition was added twice, which lead to a crash when trying to unblock that condition a second time. Deferred block condition evaluation by File objects were also not properly keeping the File object alive, which lead to some random crashes and corruption problems. Other problems were caused by the fact that the Queued state didn't handle signals/interruptions consistently. To solve these issues we remove this state entirely, along with Thread::wait_on and change the WaitQueue into a BlockCondition instead. Also, deliver signals even if there isn't going to be a context switch to another thread. Fixes #4336 and #4330
122 lines
3.7 KiB
C++
122 lines
3.7 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/Singleton.h>
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#include <Kernel/Arch/i386/CPU.h>
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#include <Kernel/Devices/RandomDevice.h>
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#include <Kernel/Random.h>
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#include <Kernel/Time/TimeManagement.h>
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namespace Kernel {
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static AK::Singleton<KernelRng> s_the;
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KernelRng& KernelRng::the()
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{
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return *s_the;
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}
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KernelRng::KernelRng()
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{
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bool supports_rdseed = Processor::current().has_feature(CPUFeature::RDSEED);
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bool supports_rdrand = Processor::current().has_feature(CPUFeature::RDRAND);
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if (supports_rdseed || supports_rdrand) {
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for (size_t i = 0; i < resource().pool_count * resource().reseed_threshold; ++i) {
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u32 value = 0;
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if (supports_rdseed) {
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asm volatile(
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"1:\n"
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"rdseed %0\n"
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"jnc 1b\n"
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: "=r"(value));
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} else {
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asm volatile(
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"1:\n"
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"rdrand %0\n"
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"jnc 1b\n"
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: "=r"(value));
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}
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this->resource().add_random_event(value, i % 32);
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}
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}
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}
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void KernelRng::wait_for_entropy()
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{
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if (!resource().is_ready()) {
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m_seed_queue.wait_on(nullptr, "KernelRng");
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}
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}
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void KernelRng::wake_if_ready()
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{
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if (resource().is_ready()) {
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m_seed_queue.wake_all();
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}
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}
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size_t EntropySource::next_source { 0 };
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void get_good_random_bytes(u8* buffer, size_t buffer_size)
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{
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KernelRng::the().wait_for_entropy();
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// FIXME: What if interrupts are disabled because we're in an interrupt?
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if (are_interrupts_enabled()) {
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LOCKER(KernelRng::the().lock());
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KernelRng::the().resource().get_random_bytes(buffer, buffer_size);
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} else {
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KernelRng::the().resource().get_random_bytes(buffer, buffer_size);
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}
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}
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void get_fast_random_bytes(u8* buffer, size_t buffer_size)
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{
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if (KernelRng::the().resource().is_ready()) {
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return get_good_random_bytes(buffer, buffer_size);
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}
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static u32 next = 1;
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union {
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u8 bytes[4];
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u32 value;
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} u;
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size_t offset = 4;
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for (size_t i = 0; i < buffer_size; ++i) {
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if (offset >= 4) {
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next = next * 1103515245 + 12345;
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u.value = next;
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offset = 0;
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}
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buffer[i] = u.bytes[offset++];
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}
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}
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}
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