ladybird/AK/Memory.h

/*
 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/Types.h>

#if defined(KERNEL)
#    include <Kernel/StdLib.h>
#else
#    include <stdlib.h>
#    include <string.h>
#endif

ALWAYS_INLINE void fast_u32_copy(u32* dest, const u32* src, size_t count)
{
#if ARCH(I386) || ARCH(X86_64)
    asm volatile(
        "rep movsl\n"
        : "+S"(src), "+D"(dest), "+c"(count)::"memory");
#else
    __builtin_memcpy(dest, src, count * 4);
#endif
}

ALWAYS_INLINE void fast_u32_fill(u32* dest, u32 value, size_t count)
{
#if ARCH(I386) || ARCH(X86_64)
    asm volatile(
        "rep stosl\n"
        : "=D"(dest), "=c"(count)
        : "D"(dest), "c"(count), "a"(value)
        : "memory");
#else
    for (auto* p = dest; p < (dest + count); ++p) {
        *p = value;
    }
#endif
}

namespace AK {
inline void secure_zero(void* ptr, size_t size)
{
    __builtin_memset(ptr, 0, size);
    // The memory barrier is here to avoid the compiler optimizing
    // away the memset when we rely on it for wiping secrets.
    asm volatile("" ::
                     : "memory");
}
}

using AK::secure_zero;