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85ea66932e
The C++ standard specifies that `free` and `operator delete` should be callable with nullptr. The non-aligned `kfree` already handles this, but because of the pointer arithmetic to obtain the allocation start pointer, the aligned version would produce undefined behavior.
104 lines
4.3 KiB
C++
104 lines
4.3 KiB
C++
/*
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* Copyright (c) 2018-2020, 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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#include <AK/Types.h>
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#include <Kernel/Debug.h>
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#include <LibC/limits.h>
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#define KMALLOC_SCRUB_BYTE 0xbb
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#define KFREE_SCRUB_BYTE 0xaa
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#define MAKE_ALIGNED_ALLOCATED(type, alignment) \
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public: \
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[[nodiscard]] void* operator new(size_t) \
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{ \
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void* ptr = kmalloc_aligned<alignment>(sizeof(type)); \
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VERIFY(ptr); \
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return ptr; \
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} \
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[[nodiscard]] void* operator new(size_t, const std::nothrow_t&) noexcept { return kmalloc_aligned<alignment>(sizeof(type)); } \
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void operator delete(void* ptr) noexcept { kfree_aligned(ptr); } \
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\
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private:
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// The C++ standard specifies that the nothrow allocation tag should live in the std namespace.
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// Otherwise, `new (std::nothrow)` calls wouldn't get resolved.
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namespace std {
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struct nothrow_t {
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explicit nothrow_t() = default;
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};
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extern const nothrow_t nothrow;
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enum class align_val_t : size_t {};
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};
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void kmalloc_init();
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[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* kmalloc_impl(size_t);
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[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* kmalloc_eternal(size_t);
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void kfree(void*);
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void kfree_sized(void*, size_t);
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struct kmalloc_stats {
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size_t bytes_allocated;
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size_t bytes_free;
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size_t bytes_eternal;
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size_t kmalloc_call_count;
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size_t kfree_call_count;
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};
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void get_kmalloc_stats(kmalloc_stats&);
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extern bool g_dump_kmalloc_stacks;
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inline void* operator new(size_t, void* p) { return p; }
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inline void* operator new[](size_t, void* p) { return p; }
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[[nodiscard]] void* operator new(size_t size);
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[[nodiscard]] void* operator new(size_t size, const std::nothrow_t&) noexcept;
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[[nodiscard]] void* operator new(size_t size, std::align_val_t);
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[[nodiscard]] void* operator new(size_t size, std::align_val_t, const std::nothrow_t&) noexcept;
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void operator delete(void* ptr) noexcept DISALLOW("All deletes in the kernel should have a known size.");
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void operator delete(void* ptr, size_t) noexcept;
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void operator delete(void* ptr, std::align_val_t) noexcept DISALLOW("All deletes in the kernel should have a known size.");
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void operator delete(void* ptr, size_t, std::align_val_t) noexcept;
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[[nodiscard]] void* operator new[](size_t size);
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[[nodiscard]] void* operator new[](size_t size, const std::nothrow_t&) noexcept;
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void operator delete[](void* ptrs) noexcept DISALLOW("All deletes in the kernel should have a known size.");
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void operator delete[](void* ptr, size_t) noexcept;
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[[gnu::malloc, gnu::alloc_size(1)]] void* kmalloc(size_t);
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template<size_t ALIGNMENT>
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[[gnu::malloc, gnu::alloc_size(1)]] inline void* kmalloc_aligned(size_t size)
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{
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static_assert(ALIGNMENT > sizeof(ptrdiff_t));
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static_assert(ALIGNMENT <= 4096);
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void* ptr = kmalloc(size + ALIGNMENT + sizeof(ptrdiff_t));
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if (ptr == nullptr)
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return ptr;
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size_t max_addr = (size_t)ptr + ALIGNMENT;
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void* aligned_ptr = (void*)(max_addr - (max_addr % ALIGNMENT));
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((ptrdiff_t*)aligned_ptr)[-1] = (ptrdiff_t)((u8*)aligned_ptr - (u8*)ptr);
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return aligned_ptr;
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}
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inline void kfree_aligned(void* ptr)
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{
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if (ptr == nullptr)
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return;
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kfree((u8*)ptr - ((const ptrdiff_t*)ptr)[-1]);
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}
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size_t kmalloc_good_size(size_t);
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void kmalloc_enable_expand();
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