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/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Atomic.h>
#include <AK/Optional.h>
#include <AK/Types.h>
#pragma once
namespace Kernel {
struct RegisterState;
[[nodiscard]] bool safe_memcpy(void* dest_ptr, void const* src_ptr, size_t n, void*& fault_at) __attribute__((used));
[[nodiscard]] ssize_t safe_strnlen(char const* str, size_t max_n, void*& fault_at) __attribute__((used));
[[nodiscard]] bool safe_memset(void* dest_ptr, int c, size_t n, void*& fault_at) __attribute__((used));
[[nodiscard]] Optional<u32> safe_atomic_fetch_add_relaxed(u32 volatile* var, u32 val) __attribute__((used));
[[nodiscard]] Optional<u32> safe_atomic_exchange_relaxed(u32 volatile* var, u32 val) __attribute__((used));
[[nodiscard]] Optional<u32> safe_atomic_load_relaxed(u32 volatile* var) __attribute__((used));
[[nodiscard]] bool safe_atomic_store_relaxed(u32 volatile* var, u32 val) __attribute__((used));
[[nodiscard]] Optional<bool> safe_atomic_compare_exchange_relaxed(u32 volatile* var, u32& expected, u32 val) __attribute__((used));
[[nodiscard]] ALWAYS_INLINE Optional<u32> safe_atomic_fetch_and_relaxed(u32 volatile* var, u32 val)
{
auto expected_value = safe_atomic_load_relaxed(var);
if (!expected_value.has_value())
return {}; // fault
u32& expected = expected_value.value();
for (;;) {
auto result = safe_atomic_compare_exchange_relaxed(var, expected, expected & val);
if (!result.has_value())
return {}; // fault
if (result.value())
return expected; // exchanged
// This is only so that we don't saturate the bus...
AK::atomic_thread_fence(AK::MemoryOrder::memory_order_acquire);
}
}
[[nodiscard]] ALWAYS_INLINE Optional<u32> safe_atomic_fetch_and_not_relaxed(u32 volatile* var, u32 val)
{
auto expected_value = safe_atomic_load_relaxed(var);
if (!expected_value.has_value())
return {}; // fault
u32& expected = expected_value.value();
for (;;) {
auto result = safe_atomic_compare_exchange_relaxed(var, expected, expected & ~val);
if (!result.has_value())
return {}; // fault
if (result.value())
return expected; // exchanged
// This is only so that we don't saturate the bus...
AK::atomic_thread_fence(AK::MemoryOrder::memory_order_acquire);
}
}
[[nodiscard]] ALWAYS_INLINE Optional<u32> safe_atomic_fetch_or_relaxed(u32 volatile* var, u32 val)
{
auto expected_value = safe_atomic_load_relaxed(var);
if (!expected_value.has_value())
return {}; // fault
u32& expected = expected_value.value();
for (;;) {
auto result = safe_atomic_compare_exchange_relaxed(var, expected, expected | val);
if (!result.has_value())
return {}; // fault
if (result.value())
return expected; // exchanged
// This is only so that we don't saturate the bus...
AK::atomic_thread_fence(AK::MemoryOrder::memory_order_acquire);
}
}
[[nodiscard]] ALWAYS_INLINE Optional<u32> safe_atomic_fetch_xor_relaxed(u32 volatile* var, u32 val)
{
auto expected_value = safe_atomic_load_relaxed(var);
if (!expected_value.has_value())
return {}; // fault
u32& expected = expected_value.value();
for (;;) {
auto result = safe_atomic_compare_exchange_relaxed(var, expected, expected ^ val);
if (!result.has_value())
return {}; // fault
if (result.value())
return expected; // exchanged
// This is only so that we don't saturate the bus...
AK::atomic_thread_fence(AK::MemoryOrder::memory_order_acquire);
}
}
bool handle_safe_access_fault(RegisterState& regs, FlatPtr fault_address);
}
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