Atmosphere/libraries/libmesosphere/include/mesosphere/kern_k_slab_heap.hpp
2020-12-18 13:31:01 -08:00

234 lines
7.3 KiB
C++

/*
* Copyright (c) 2018-2020 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/>.
*/
#pragma once
#include <mesosphere/kern_common.hpp>
#include <mesosphere/kern_k_typed_address.hpp>
#if defined(ATMOSPHERE_ARCH_ARM64)
#include <mesosphere/arch/arm64/kern_k_slab_heap_impl.hpp>
namespace ams::kern {
using ams::kern::arch::arm64::AllocateFromSlabAtomic;
using ams::kern::arch::arm64::FreeToSlabAtomic;
}
#else
#error "Unknown architecture for KSlabHeapImpl"
#endif
namespace ams::kern {
namespace impl {
class KSlabHeapImpl {
NON_COPYABLE(KSlabHeapImpl);
NON_MOVEABLE(KSlabHeapImpl);
public:
struct Node {
Node *next;
};
private:
Node * m_head;
size_t m_obj_size;
public:
constexpr KSlabHeapImpl() : m_head(nullptr), m_obj_size(0) { MESOSPHERE_ASSERT_THIS(); }
void Initialize(size_t size) {
MESOSPHERE_INIT_ABORT_UNLESS(m_head == nullptr);
m_obj_size = size;
}
Node *GetHead() const {
return m_head;
}
size_t GetObjectSize() const {
return m_obj_size;
}
void *Allocate() {
MESOSPHERE_ASSERT_THIS();
return AllocateFromSlabAtomic(std::addressof(m_head));
}
void Free(void *obj) {
MESOSPHERE_ASSERT_THIS();
Node *node = reinterpret_cast<Node *>(obj);
return FreeToSlabAtomic(std::addressof(m_head), node);
}
};
}
class KSlabHeapBase {
NON_COPYABLE(KSlabHeapBase);
NON_MOVEABLE(KSlabHeapBase);
private:
using Impl = impl::KSlabHeapImpl;
private:
Impl m_impl;
uintptr_t m_peak;
uintptr_t m_start;
uintptr_t m_end;
private:
ALWAYS_INLINE Impl *GetImpl() {
return std::addressof(m_impl);
}
ALWAYS_INLINE const Impl *GetImpl() const {
return std::addressof(m_impl);
}
public:
constexpr KSlabHeapBase() : m_impl(), m_peak(0), m_start(0), m_end(0) { MESOSPHERE_ASSERT_THIS(); }
ALWAYS_INLINE bool Contains(uintptr_t address) const {
return m_start <= address && address < m_end;
}
void InitializeImpl(size_t obj_size, void *memory, size_t memory_size) {
MESOSPHERE_ASSERT_THIS();
/* Ensure we don't initialize a slab using null memory. */
MESOSPHERE_ABORT_UNLESS(memory != nullptr);
/* Initialize the base allocator. */
this->GetImpl()->Initialize(obj_size);
/* Set our tracking variables. */
const size_t num_obj = (memory_size / obj_size);
m_start = reinterpret_cast<uintptr_t>(memory);
m_end = m_start + num_obj * obj_size;
m_peak = m_start;
/* Free the objects. */
u8 *cur = reinterpret_cast<u8 *>(m_end);
for (size_t i = 0; i < num_obj; i++) {
cur -= obj_size;
this->GetImpl()->Free(cur);
}
}
size_t GetSlabHeapSize() const {
return (m_end - m_start) / this->GetObjectSize();
}
size_t GetObjectSize() const {
return this->GetImpl()->GetObjectSize();
}
void *AllocateImpl() {
MESOSPHERE_ASSERT_THIS();
void *obj = this->GetImpl()->Allocate();
/* Track the allocated peak. */
#if defined(MESOSPHERE_BUILD_FOR_DEBUGGING)
if (AMS_LIKELY(obj != nullptr)) {
static_assert(std::atomic_ref<uintptr_t>::is_always_lock_free);
std::atomic_ref<uintptr_t> peak_ref(m_peak);
const uintptr_t alloc_peak = reinterpret_cast<uintptr_t>(obj) + this->GetObjectSize();
uintptr_t cur_peak = m_peak;
do {
if (alloc_peak <= cur_peak) {
break;
}
} while (!peak_ref.compare_exchange_strong(cur_peak, alloc_peak));
}
#endif
return obj;
}
void FreeImpl(void *obj) {
MESOSPHERE_ASSERT_THIS();
/* Don't allow freeing an object that wasn't allocated from this heap. */
MESOSPHERE_ABORT_UNLESS(this->Contains(reinterpret_cast<uintptr_t>(obj)));
this->GetImpl()->Free(obj);
}
size_t GetObjectIndexImpl(const void *obj) const {
return (reinterpret_cast<uintptr_t>(obj) - m_start) / this->GetObjectSize();
}
size_t GetPeakIndex() const {
return this->GetObjectIndexImpl(reinterpret_cast<const void *>(m_peak));
}
uintptr_t GetSlabHeapAddress() const {
return m_start;
}
size_t GetNumRemaining() const {
size_t remaining = 0;
/* Only calculate the number of remaining objects under debug configuration. */
#if defined(MESOSPHERE_BUILD_FOR_DEBUGGING)
while (true) {
auto *cur = this->GetImpl()->GetHead();
remaining = 0;
while (this->Contains(reinterpret_cast<uintptr_t>(cur))) {
++remaining;
cur = cur->next;
}
if (cur == nullptr) {
break;
}
}
#endif
return remaining;
}
};
template<typename T>
class KSlabHeap : public KSlabHeapBase {
public:
constexpr KSlabHeap() : KSlabHeapBase() { /* ... */ }
void Initialize(void *memory, size_t memory_size) {
this->InitializeImpl(sizeof(T), memory, memory_size);
}
T *Allocate() {
T *obj = reinterpret_cast<T *>(this->AllocateImpl());
if (AMS_LIKELY(obj != nullptr)) {
new (obj) T();
}
return obj;
}
void Free(T *obj) {
this->FreeImpl(obj);
}
size_t GetObjectIndex(const T *obj) const {
return this->GetObjectIndexImpl(obj);
}
};
}