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65b420f996
These instances were detected by searching for files that include AK/Memory.h, but don't match the regex: \\b(fast_u32_copy|fast_u32_fill|secure_zero|timing_safe_compare)\\b This regex is pessimistic, so there might be more files that don't actually use any memory function. In theory, one might use LibCPP to detect things like this automatically, but let's do this one step after another.
66 lines
2.3 KiB
C++
66 lines
2.3 KiB
C++
/*
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* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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// KBuffer: Memory buffer backed by a kernel region.
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//
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// The memory is allocated via the global kernel-only page allocator, rather than via
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// kmalloc() which is what ByteBuffer/Vector/etc will use.
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//
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// This makes KBuffer a little heavier to allocate, but much better for large and/or
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// long-lived allocations, since they don't put all that weight and pressure on the
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// severely limited kmalloc heap.
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#include <AK/Assertions.h>
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#include <AK/StringView.h>
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#include <Kernel/Memory/MemoryManager.h>
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namespace Kernel {
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class [[nodiscard]] KBuffer {
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public:
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static ErrorOr<NonnullOwnPtr<KBuffer>> try_create_with_size(StringView name, size_t size, Memory::Region::Access access = Memory::Region::Access::ReadWrite, AllocationStrategy strategy = AllocationStrategy::Reserve)
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{
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auto rounded_size = TRY(Memory::page_round_up(size));
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auto region = TRY(MM.allocate_kernel_region(rounded_size, name, access, strategy));
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return TRY(adopt_nonnull_own_or_enomem(new (nothrow) KBuffer { size, move(region) }));
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}
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static ErrorOr<NonnullOwnPtr<KBuffer>> try_create_with_bytes(StringView name, ReadonlyBytes bytes, Memory::Region::Access access = Memory::Region::Access::ReadWrite, AllocationStrategy strategy = AllocationStrategy::Reserve)
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{
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auto buffer = TRY(try_create_with_size(name, bytes.size(), access, strategy));
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memcpy(buffer->data(), bytes.data(), bytes.size());
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return buffer;
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}
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[[nodiscard]] u8* data() { return m_region->vaddr().as_ptr(); }
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[[nodiscard]] u8 const* data() const { return m_region->vaddr().as_ptr(); }
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[[nodiscard]] size_t size() const { return m_size; }
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[[nodiscard]] size_t capacity() const { return m_region->size(); }
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[[nodiscard]] ReadonlyBytes bytes() const { return { data(), size() }; }
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[[nodiscard]] Bytes bytes() { return { data(), size() }; }
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void set_size(size_t size)
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{
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VERIFY(size <= capacity());
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m_size = size;
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}
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private:
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explicit KBuffer(size_t size, NonnullOwnPtr<Memory::Region> region)
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: m_size(size)
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, m_region(move(region))
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{
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}
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size_t m_size { 0 };
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NonnullOwnPtr<Memory::Region> m_region;
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};
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}
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