ladybird/Kernel/Heap/kmalloc.h
Daniel Bertalan 85ea66932e Kernel: Allow kfree_aligned to be called on null pointers
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.
2021-08-13 22:02:23 +02:00

104 lines
4.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Types.h>
#include <Kernel/Debug.h>
#include <LibC/limits.h>
#define KMALLOC_SCRUB_BYTE 0xbb
#define KFREE_SCRUB_BYTE 0xaa
#define MAKE_ALIGNED_ALLOCATED(type, alignment) \
public: \
[[nodiscard]] void* operator new(size_t) \
{ \
void* ptr = kmalloc_aligned<alignment>(sizeof(type)); \
VERIFY(ptr); \
return ptr; \
} \
[[nodiscard]] void* operator new(size_t, const std::nothrow_t&) noexcept { return kmalloc_aligned<alignment>(sizeof(type)); } \
void operator delete(void* ptr) noexcept { kfree_aligned(ptr); } \
\
private:
// The C++ standard specifies that the nothrow allocation tag should live in the std namespace.
// Otherwise, `new (std::nothrow)` calls wouldn't get resolved.
namespace std {
struct nothrow_t {
explicit nothrow_t() = default;
};
extern const nothrow_t nothrow;
enum class align_val_t : size_t {};
};
void kmalloc_init();
[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* kmalloc_impl(size_t);
[[gnu::malloc, gnu::returns_nonnull, gnu::alloc_size(1)]] void* kmalloc_eternal(size_t);
void kfree(void*);
void kfree_sized(void*, size_t);
struct kmalloc_stats {
size_t bytes_allocated;
size_t bytes_free;
size_t bytes_eternal;
size_t kmalloc_call_count;
size_t kfree_call_count;
};
void get_kmalloc_stats(kmalloc_stats&);
extern bool g_dump_kmalloc_stacks;
inline void* operator new(size_t, void* p) { return p; }
inline void* operator new[](size_t, void* p) { return p; }
[[nodiscard]] void* operator new(size_t size);
[[nodiscard]] void* operator new(size_t size, const std::nothrow_t&) noexcept;
[[nodiscard]] void* operator new(size_t size, std::align_val_t);
[[nodiscard]] void* operator new(size_t size, std::align_val_t, const std::nothrow_t&) noexcept;
void operator delete(void* ptr) noexcept DISALLOW("All deletes in the kernel should have a known size.");
void operator delete(void* ptr, size_t) noexcept;
void operator delete(void* ptr, std::align_val_t) noexcept DISALLOW("All deletes in the kernel should have a known size.");
void operator delete(void* ptr, size_t, std::align_val_t) noexcept;
[[nodiscard]] void* operator new[](size_t size);
[[nodiscard]] void* operator new[](size_t size, const std::nothrow_t&) noexcept;
void operator delete[](void* ptrs) noexcept DISALLOW("All deletes in the kernel should have a known size.");
void operator delete[](void* ptr, size_t) noexcept;
[[gnu::malloc, gnu::alloc_size(1)]] void* kmalloc(size_t);
template<size_t ALIGNMENT>
[[gnu::malloc, gnu::alloc_size(1)]] inline void* kmalloc_aligned(size_t size)
{
static_assert(ALIGNMENT > sizeof(ptrdiff_t));
static_assert(ALIGNMENT <= 4096);
void* ptr = kmalloc(size + ALIGNMENT + sizeof(ptrdiff_t));
if (ptr == nullptr)
return ptr;
size_t max_addr = (size_t)ptr + ALIGNMENT;
void* aligned_ptr = (void*)(max_addr - (max_addr % ALIGNMENT));
((ptrdiff_t*)aligned_ptr)[-1] = (ptrdiff_t)((u8*)aligned_ptr - (u8*)ptr);
return aligned_ptr;
}
inline void kfree_aligned(void* ptr)
{
if (ptr == nullptr)
return;
kfree((u8*)ptr - ((const ptrdiff_t*)ptr)[-1]);
}
size_t kmalloc_good_size(size_t);
void kmalloc_enable_expand();