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256 lines
8.8 KiB
C++
256 lines
8.8 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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#include <AK/Assertions.h>
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#include <AK/MemMem.h>
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#include <AK/Types.h>
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#include <Kernel/Arch/SafeMem.h>
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#include <Kernel/Arch/SmapDisabler.h>
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#include <Kernel/Memory/MemoryManager.h>
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#include <Kernel/StdLib.h>
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ErrorOr<NonnullOwnPtr<Kernel::KString>> try_copy_kstring_from_user(Userspace<char const*> user_str, size_t user_str_size)
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{
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bool is_user = Kernel::Memory::is_user_range(user_str.vaddr(), user_str_size);
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if (!is_user)
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return EFAULT;
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Kernel::SmapDisabler disabler;
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void* fault_at;
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ssize_t length = Kernel::safe_strnlen(user_str.unsafe_userspace_ptr(), user_str_size, fault_at);
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if (length < 0) {
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dbgln("copy_kstring_from_user({:p}, {}) failed at {} (strnlen)", static_cast<void const*>(user_str.unsafe_userspace_ptr()), user_str_size, VirtualAddress { fault_at });
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return EFAULT;
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}
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char* buffer;
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auto new_string = TRY(Kernel::KString::try_create_uninitialized(length, buffer));
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buffer[length] = '\0';
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if (length == 0)
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return new_string;
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if (!Kernel::safe_memcpy(buffer, user_str.unsafe_userspace_ptr(), (size_t)length, fault_at)) {
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dbgln("copy_kstring_from_user({:p}, {}) failed at {} (memcpy)", static_cast<void const*>(user_str.unsafe_userspace_ptr()), user_str_size, VirtualAddress { fault_at });
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return EFAULT;
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}
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return new_string;
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}
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ErrorOr<Time> copy_time_from_user(timespec const* ts_user)
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{
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timespec ts {};
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TRY(copy_from_user(&ts, ts_user, sizeof(timespec)));
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return Time::from_timespec(ts);
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}
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ErrorOr<Time> copy_time_from_user(timeval const* tv_user)
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{
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timeval tv {};
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TRY(copy_from_user(&tv, tv_user, sizeof(timeval)));
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return Time::from_timeval(tv);
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}
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template<>
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ErrorOr<Time> copy_time_from_user<timeval const>(Userspace<timeval const*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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template<>
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ErrorOr<Time> copy_time_from_user<timeval>(Userspace<timeval*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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template<>
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ErrorOr<Time> copy_time_from_user<timespec const>(Userspace<timespec const*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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template<>
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ErrorOr<Time> copy_time_from_user<timespec>(Userspace<timespec*> src) { return copy_time_from_user(src.unsafe_userspace_ptr()); }
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Optional<u32> user_atomic_fetch_add_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_add_relaxed(var, val);
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}
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Optional<u32> user_atomic_exchange_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_exchange_relaxed(var, val);
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}
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Optional<u32> user_atomic_load_relaxed(u32 volatile* var)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_load_relaxed(var);
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}
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bool user_atomic_store_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return false; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return false;
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_store_relaxed(var, val);
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}
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Optional<bool> user_atomic_compare_exchange_relaxed(u32 volatile* var, u32& expected, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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VERIFY(!Kernel::Memory::is_user_range(VirtualAddress(&expected), sizeof(expected)));
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_compare_exchange_relaxed(var, expected, val);
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}
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Optional<u32> user_atomic_fetch_and_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_and_relaxed(var, val);
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}
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Optional<u32> user_atomic_fetch_and_not_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_and_not_relaxed(var, val);
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}
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Optional<u32> user_atomic_fetch_or_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_or_relaxed(var, val);
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}
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Optional<u32> user_atomic_fetch_xor_relaxed(u32 volatile* var, u32 val)
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{
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if (FlatPtr(var) & 3)
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return {}; // not aligned!
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(FlatPtr(var)), sizeof(*var));
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if (!is_user)
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return {};
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Kernel::SmapDisabler disabler;
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return Kernel::safe_atomic_fetch_xor_relaxed(var, val);
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}
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ErrorOr<void> copy_to_user(void* dest_ptr, void const* src_ptr, size_t n)
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{
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if (!Kernel::Memory::is_user_range(VirtualAddress(dest_ptr), n))
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return EFAULT;
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VERIFY(!Kernel::Memory::is_user_range(VirtualAddress(src_ptr), n));
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Kernel::SmapDisabler disabler;
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void* fault_at;
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if (!Kernel::safe_memcpy(dest_ptr, src_ptr, n, fault_at)) {
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VERIFY(VirtualAddress(fault_at) >= VirtualAddress(dest_ptr) && VirtualAddress(fault_at) <= VirtualAddress((FlatPtr)dest_ptr + n));
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dbgln("copy_to_user({:p}, {:p}, {}) failed at {}", dest_ptr, src_ptr, n, VirtualAddress { fault_at });
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return EFAULT;
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}
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return {};
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}
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ErrorOr<void> copy_from_user(void* dest_ptr, void const* src_ptr, size_t n)
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{
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if (!Kernel::Memory::is_user_range(VirtualAddress(src_ptr), n))
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return EFAULT;
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VERIFY(!Kernel::Memory::is_user_range(VirtualAddress(dest_ptr), n));
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Kernel::SmapDisabler disabler;
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void* fault_at;
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if (!Kernel::safe_memcpy(dest_ptr, src_ptr, n, fault_at)) {
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VERIFY(VirtualAddress(fault_at) >= VirtualAddress(src_ptr) && VirtualAddress(fault_at) <= VirtualAddress((FlatPtr)src_ptr + n));
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dbgln("copy_from_user({:p}, {:p}, {}) failed at {}", dest_ptr, src_ptr, n, VirtualAddress { fault_at });
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return EFAULT;
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}
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return {};
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}
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ErrorOr<void> memset_user(void* dest_ptr, int c, size_t n)
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{
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bool is_user = Kernel::Memory::is_user_range(VirtualAddress(dest_ptr), n);
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if (!is_user)
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return EFAULT;
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Kernel::SmapDisabler disabler;
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void* fault_at;
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if (!Kernel::safe_memset(dest_ptr, c, n, fault_at)) {
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dbgln("memset_user({:p}, {}, {}) failed at {}", dest_ptr, c, n, VirtualAddress { fault_at });
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return EFAULT;
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}
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return {};
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}
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#if defined(AK_COMPILER_CLANG) && defined(ENABLE_KERNEL_LTO)
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// Due to a chicken-and-egg situation, certain linker-defined symbols that are added on-demand (like the GOT)
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// need to be present before LTO bitcode files are compiled. And since we don't link to any native object files,
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// the linker does not know that _GLOBAL_OFFSET_TABLE_ is needed, so it doesn't define it, so linking as a PIE fails.
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// See https://bugs.llvm.org/show_bug.cgi?id=39634
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FlatPtr missing_got_workaround()
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{
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extern volatile FlatPtr _GLOBAL_OFFSET_TABLE_;
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return _GLOBAL_OFFSET_TABLE_;
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}
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#endif
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extern "C" {
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void const* memmem(void const* haystack, size_t haystack_length, void const* needle, size_t needle_length)
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{
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return AK::memmem(haystack, haystack_length, needle, needle_length);
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}
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// Functions that are automatically called by the C++ compiler.
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// Declare them first, to tell the silly compiler that they are indeed being used.
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[[noreturn]] void __stack_chk_fail() __attribute__((used));
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[[noreturn]] void __stack_chk_fail_local() __attribute__((used));
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extern "C" int __cxa_atexit(void (*)(void*), void*, void*);
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[[noreturn]] void __cxa_pure_virtual();
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[[noreturn]] void __stack_chk_fail()
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{
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VERIFY_NOT_REACHED();
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}
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[[noreturn]] void __stack_chk_fail_local()
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{
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VERIFY_NOT_REACHED();
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}
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extern "C" int __cxa_atexit(void (*)(void*), void*, void*)
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{
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VERIFY_NOT_REACHED();
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return 0;
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}
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[[noreturn]] void __cxa_pure_virtual()
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{
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VERIFY_NOT_REACHED();
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}
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}
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