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Atmosphere/libraries/libstratosphere/source/os/impl/os_tls_manager.cpp

142 lines
4.6 KiB
C++

/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stratosphere.hpp>
#include "os_tls_manager.hpp"
#include "os_thread_manager.hpp"
namespace ams::os::impl {
/* TODO: Should we migrate away from libnx to this on NX at some point? */
#if !defined(ATMOSPHERE_OS_HORIZON)
namespace {
constexpr auto TryCallDestructorCount = 4;
void DefaultTlsDestructor(uintptr_t) {
/* ... */
}
}
void TlsManager::InvokeTlsDestructors() {
/* Get the curent thread. */
auto * const thread = impl::GetCurrentThread();
/* Call all destructors. */
for (int slot = 0; slot < static_cast<int>(TotalTlsSlotCountMax); ++slot) {
if (const auto destructor = m_destructors[slot]; destructor != nullptr) {
destructor(thread->tls_value_array[slot]);
}
thread->tls_value_array[slot] = 0;
}
/* Verify all tls values are wiped, trying up to four times. */
for (auto i = 0; i < TryCallDestructorCount; ++i) {
bool all_cleared = true;
for (auto slot = 0; slot < static_cast<int>(TotalTlsSlotCountMax); ++slot) {
if (thread->tls_value_array[slot] != 0) {
all_cleared = false;
if (const auto destructor = m_destructors[slot]; destructor != nullptr) {
destructor(thread->tls_value_array[slot]);
}
thread->tls_value_array[slot] = 0;
}
}
if (all_cleared) {
break;
}
}
}
bool TlsManager::AllocateTlsSlot(TlsSlot *out, TlsDestructor destructor, bool sdk) {
/* Decide on a slot. */
int slot;
{
/* Lock appropriately. */
std::scoped_lock lk(util::GetReference(impl::GetCurrentThread()->cs_thread));
std::scoped_lock lk2(m_cs);
/* If we're out of tls slots, fail. */
if (!sdk && m_used >= static_cast<int>(TlsSlotCountMax)) {
return false;
}
/* Get a slot. */
slot = SearchUnusedTlsSlotUnsafe(sdk);
/* Set the destructor. */
m_destructors[slot] = (destructor != nullptr) ? destructor : DefaultTlsDestructor;
/* Increment our used count, if the slot was a user slot. */
if (!sdk) {
++m_used;
}
}
/* Zero the slot in all threads. */
GetThreadManager().SetZeroToAllThreadsTlsSafe(slot);
/* Set the output slot's value. */
out->_value = slot;
return true;
}
void TlsManager::FreeTlsSlot(TlsSlot slot) {
/* Get the slot's index. */
const auto slot_idx = slot._value;
/* Lock appropriately. */
std::scoped_lock lk(util::GetReference(impl::GetCurrentThread()->cs_thread));
std::scoped_lock lk2(m_cs);
/* Verify the slot is allocated. */
AMS_ABORT_UNLESS(m_destructors[slot_idx] != nullptr);
/* Free the slot. */
m_destructors[slot_idx] = nullptr;
/* Decrement our used count, if the slot was a user slot. */
if (slot_idx < TlsSlotCountMax) {
--m_used;
}
}
int TlsManager::SearchUnusedTlsSlotUnsafe(bool sdk) {
if (sdk) {
/* Search backwards for an unused slot. */
for (int slot = static_cast<int>(TotalTlsSlotCountMax) - 1; slot >= static_cast<int>(TlsSlotCountMax + SdkInternalTlsCount); --slot) {
if (m_destructors[slot] == nullptr) {
return slot;
}
}
AMS_ABORT("Failed to allocate SdkTlsSlot");
} else {
/* Search forwards for an unused slot. */
for (int slot = 0; slot < static_cast<int>(TlsSlotCountMax); ++slot) {
if (m_destructors[slot] == nullptr) {
return slot;
}
}
AMS_ABORT("Failed to allocate TlsSlot");
}
}
#endif
}