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