Kernel: Stop requiring working malloc for syscall.h includes

Fixes #13869

Kernel/API/Syscall.h

@@ -6,7 +6,6 @@
 
 #pragma once
 
-#include <AK/StringView.h>
 #include <AK/Types.h>
 #include <AK/Userspace.h>
 
@@ -201,21 +200,6 @@ enum Function {
         __Count
 };
 
-constexpr StringView to_string(Function function)
-{
-    switch (function) {
-#undef __ENUMERATE_SYSCALL
-#define __ENUMERATE_SYSCALL(sys_call, needs_lock) \
-    case SC_##sys_call:                           \
-        return #sys_call##sv;
-        ENUMERATE_SYSCALLS(__ENUMERATE_SYSCALL)
-#undef __ENUMERATE_SYSCALL
-    default:
-        break;
-    }
-    return "Unknown"sv;
-}
-
 #ifdef __serenity__
 struct StringArgument {
     char const* characters;

Kernel/API/SyscallString.h

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2022, Patrick Meyer <git@the-space.agency>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/StringView.h>
+#include <Kernel/API/Syscall.h>
+
+namespace Kernel::Syscall {
+
+// Separate header so syscall.h doesn't depend on malloc.
+// https://github.com/SerenityOS/serenity/issues/13869
+constexpr StringView to_string(Function function)
+{
+    switch (function) {
+#undef __ENUMERATE_SYSCALL
+#define __ENUMERATE_SYSCALL(sys_call, needs_lock) \
+    case SC_##sys_call:                           \
+        return #sys_call##sv;
+        ENUMERATE_SYSCALLS(__ENUMERATE_SYSCALL)
+#undef __ENUMERATE_SYSCALL
+    default:
+        break;
+    }
+    return "Unknown"sv;
+}
+
+}

Tests/Kernel/fuzz-syscalls.cpp

@@ -9,6 +9,7 @@
 #include <AK/String.h>
 #include <AK/StringBuilder.h>
 #include <AK/Vector.h>
+#include <Kernel/API/SyscallString.h>
 #include <errno.h>
 #include <signal.h>
 #include <stdio.h>

Userland/DevTools/UserspaceEmulator/Emulator_syscalls.cpp

@@ -12,6 +12,7 @@
 #include <AK/Debug.h>
 #include <AK/FileStream.h>
 #include <AK/Format.h>
+#include <Kernel/API/SyscallString.h>
 #include <alloca.h>
 #include <fcntl.h>
 #include <sched.h>

Userland/Utilities/functrace.cpp

@@ -8,6 +8,7 @@
 #include <AK/HashMap.h>
 #include <AK/NonnullOwnPtr.h>
 #include <AK/StringBuilder.h>
+#include <Kernel/API/SyscallString.h>
 #include <LibC/sys/arch/i386/regs.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/File.h>

Userland/Utilities/strace.cpp

@@ -9,6 +9,7 @@
 #include <AK/IPv4Address.h>
 #include <AK/StdLibExtras.h>
 #include <AK/Types.h>
+#include <Kernel/API/SyscallString.h>
 #include <LibC/sys/arch/i386/regs.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/File.h>

Userland/Utilities/syscall.cpp

@@ -9,6 +9,7 @@
 #include <AK/Debug.h>
 #include <AK/Iterator.h>
 #include <AK/Vector.h>
+#include <Kernel/API/SyscallString.h>
 #include <LibCore/ArgsParser.h>
 #include <LibMain/Main.h>
 #include <errno_codes.h>