Atmosphere/libraries/libmesosphere/source/kern_k_page_heap.cpp
2020-02-07 04:58:35 -08:00

136 lines
5.5 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/>.
*/
#include <mesosphere.hpp>
namespace ams::kern {
void KPageHeap::Initialize(KVirtualAddress address, size_t size, KVirtualAddress metadata_address, size_t metadata_size, const size_t *block_shifts, size_t num_block_shifts) {
/* Check our assumptions. */
MESOSPHERE_ASSERT(util::IsAligned(GetInteger(address), PageSize));
MESOSPHERE_ASSERT(util::IsAligned(size, PageSize));
MESOSPHERE_ASSERT(0 < num_block_shifts && num_block_shifts <= NumMemoryBlockPageShifts);
const KVirtualAddress metadata_end = metadata_address + metadata_size;
/* Set our members. */
this->heap_address = address;
this->heap_size = size;
this->num_blocks = num_block_shifts;
/* Setup bitmaps. */
u64 *cur_bitmap_storage = GetPointer<u64>(metadata_address);
for (size_t i = 0; i < num_block_shifts; i++) {
const size_t cur_block_shift = block_shifts[i];
const size_t next_block_shift = (i != num_block_shifts - 1) ? block_shifts[i + 1] : 0;
cur_bitmap_storage = this->blocks[i].Initialize(this->heap_address, this->heap_size, cur_block_shift, next_block_shift, cur_bitmap_storage);
}
/* Ensure we didn't overextend our bounds. */
MESOSPHERE_ABORT_UNLESS(KVirtualAddress(cur_bitmap_storage) <= metadata_end);
}
size_t KPageHeap::GetNumFreePages() const {
size_t num_free = 0;
for (size_t i = 0; i < this->num_blocks; i++) {
num_free += this->blocks[i].GetNumFreePages();
}
return num_free;
}
KVirtualAddress KPageHeap::AllocateBlock(s32 index) {
const size_t needed_size = this->blocks[index].GetSize();
for (s32 i = index; i < static_cast<s32>(this->num_blocks); i++) {
if (const KVirtualAddress addr = this->blocks[i].PopBlock(); addr != Null<KVirtualAddress>) {
if (const size_t allocated_size = this->blocks[i].GetSize(); allocated_size > needed_size) {
this->Free(addr + needed_size, (allocated_size - needed_size) / PageSize);
}
return addr;
}
}
return Null<KVirtualAddress>;
}
void KPageHeap::FreeBlock(KVirtualAddress block, s32 index) {
do {
block = this->blocks[index++].PushBlock(block);
} while (block != Null<KVirtualAddress>);
}
void KPageHeap::Free(KVirtualAddress addr, size_t num_pages) {
/* Freeing no pages is a no-op. */
if (num_pages == 0) {
return;
}
/* Find the largest block size that we can free, and free as many as possible. */
s32 big_index = static_cast<s32>(this->num_blocks) - 1;
const KVirtualAddress start = addr;
const KVirtualAddress end = addr + num_pages * PageSize;
KVirtualAddress before_start = start;
KVirtualAddress before_end = start;
KVirtualAddress after_start = end;
KVirtualAddress after_end = end;
while (big_index >= 0) {
const size_t block_size = this->blocks[big_index].GetSize();
const KVirtualAddress big_start = util::AlignUp(GetInteger(start), block_size);
const KVirtualAddress big_end = util::AlignDown(GetInteger(end), block_size);
if (big_start < big_end) {
/* Free as many big blocks as we can. */
for (auto block = big_start; block < big_end; block += block_size) {
this->FreeBlock(block, big_index);
}
before_end = big_start;
after_start = big_end;
break;
}
big_index--;
}
MESOSPHERE_ASSERT(big_index >= 0);
/* Free space before the big blocks. */
for (s32 i = big_index; i >= 0; i--) {
const size_t block_size = this->blocks[i].GetSize();
while (before_start + block_size <= before_end) {
before_end -= block_size;
this->FreeBlock(before_end, i);
}
}
/* Free space after the big blocks. */
for (s32 i = big_index; i >= 0; i--) {
const size_t block_size = this->blocks[i].GetSize();
while (after_start + block_size <= after_end) {
after_start += block_size;
this->FreeBlock(after_start, i);
}
}
}
size_t KPageHeap::CalculateMetadataOverheadSize(size_t region_size, const size_t *block_shifts, size_t num_block_shifts) {
size_t overhead_size = 0;
for (size_t i = 0; i < num_block_shifts; i++) {
const size_t cur_block_shift = block_shifts[i];
const size_t next_block_shift = (i != num_block_shifts - 1) ? block_shifts[i + 1] : 0;
overhead_size += KPageHeap::Block::CalculateMetadataOverheadSize(region_size, cur_block_shift, next_block_shift);
}
return util::AlignUp(overhead_size, PageSize);
}
}