Userland: Add LibSystem and funnel all syscalls through it

This achieves two things:

- Programs can now intentionally perform arbitrary syscalls by calling
  syscall(). This allows us to work on things like syscall fuzzing.

- It restricts the ability of userspace to make syscalls to a single
  4KB page of code. In order to call the kernel directly, an attacker
  must now locate this page and call through it.

47 files changed, 164 insertions, 47 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 56501c6fe4..d8a033513f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -140,6 +140,7 @@ add_link_options(--sysroot ${CMAKE_BINARY_DIR}/Root)
 
 include_directories(Userland/Libraries/LibC)
 include_directories(Userland/Libraries/LibM)
+include_directories(Userland/Libraries/LibSystem)
 include_directories(Userland/Services)
 include_directories(Userland)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
diff --git a/Kernel/API/Syscall.h b/Kernel/API/Syscall.h
index 5de5ecb669..984405b84b 100644
--- a/Kernel/API/Syscall.h
+++ b/Kernel/API/Syscall.h
@@ -504,7 +504,6 @@ inline uintptr_t invoke(Function function, T1 arg1, T2 arg2, T3 arg3)
 #define __ENUMERATE_SYSCALL(x) using Syscall::SC_##x;
 ENUMERATE_SYSCALLS(__ENUMERATE_SYSCALL)
 #undef __ENUMERATE_SYSCALL
-#define syscall Syscall::invoke
 
 }
 
diff --git a/Userland/DevTools/UserspaceEmulator/Emulator.cpp b/Userland/DevTools/UserspaceEmulator/Emulator.cpp
index ef72f6d04a..bc5544805c 100644
--- a/Userland/DevTools/UserspaceEmulator/Emulator.cpp
+++ b/Userland/DevTools/UserspaceEmulator/Emulator.cpp
@@ -32,7 +32,6 @@
 #include <AK/Format.h>
 #include <AK/LexicalPath.h>
 #include <AK/MappedFile.h>
-#include <Kernel/API/Syscall.h>
 #include <LibELF/AuxiliaryVector.h>
 #include <LibELF/Image.h>
 #include <LibELF/Validation.h>
@@ -53,6 +52,7 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/uio.h>
+#include <syscall.h>
 #include <termios.h>
 #include <unistd.h>
 
diff --git a/Userland/DynamicLoader/CMakeLists.txt b/Userland/DynamicLoader/CMakeLists.txt
index e96b2b4ef4..019b7eaf89 100644
--- a/Userland/DynamicLoader/CMakeLists.txt
+++ b/Userland/DynamicLoader/CMakeLists.txt
@@ -10,11 +10,12 @@ set(ELF_SOURCES ${ELF_SOURCES} ../Libraries/LibELF/Arch/i386/plt_trampoline.S)
 file(GLOB LIBC_SOURCES1 "../Libraries/LibC/*.cpp")
 file(GLOB LIBC_SOURCES2 "../Libraries/LibC/*/*.cpp")
 file(GLOB LIBC_SOURCES3 "../Libraries/LibC/*.S")
+file(GLOB LIBSYSTEM_SOURCES "../Libraries/LibSystem/*.cpp")
 
 list(FILTER LIBC_SOURCES1 EXCLUDE REGEX ".+crt0.cpp")
 list(FILTER LIBC_SOURCES1 EXCLUDE REGEX ".+crt0.+.cpp")
 
-set(SOURCES ${LOADER_SOURCES} ${AK_SOURCES} ${ELF_SOURCES} ${LIBC_SOURCES1} ${LIBC_SOURCES2} ${LIBC_SOURCES3})
+set(SOURCES ${LOADER_SOURCES} ${AK_SOURCES} ${ELF_SOURCES} ${LIBC_SOURCES1} ${LIBC_SOURCES2} ${LIBC_SOURCES3} ${LIBSYSTEM_SOURCES})
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-rtti -nostdlib -pie -fpic -DNO_TLS")
 
diff --git a/Userland/Libraries/CMakeLists.txt b/Userland/Libraries/CMakeLists.txt
index 9e54e78156..ed30460a48 100644
--- a/Userland/Libraries/CMakeLists.txt
+++ b/Userland/Libraries/CMakeLists.txt
@@ -27,6 +27,7 @@ add_subdirectory(LibProtocol)
 add_subdirectory(LibPthread)
 add_subdirectory(LibRegex)
 add_subdirectory(LibSymbolClient)
+add_subdirectory(LibSystem)
 add_subdirectory(LibTar)
 add_subdirectory(LibTextCodec)
 add_subdirectory(LibThread)
diff --git a/Userland/Libraries/LibC/CMakeLists.txt b/Userland/Libraries/LibC/CMakeLists.txt
index 393addb934..cab661dcb6 100644
--- a/Userland/Libraries/LibC/CMakeLists.txt
+++ b/Userland/Libraries/LibC/CMakeLists.txt
@@ -81,10 +81,10 @@ add_custom_command(
 set(SOURCES ${LIBC_SOURCES} ${AK_SOURCES} ${ELF_SOURCES})
 
 serenity_libc_static(LibCStatic c)
-target_link_libraries(LibCStatic crt0 ssp)
-add_dependencies(LibCStatic LibM)
+target_link_libraries(LibCStatic crt0 ssp system)
+add_dependencies(LibCStatic LibM LibSystem)
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -static-libstdc++")
 serenity_libc(LibC c)
-target_link_libraries(LibC crt0 ssp)
-add_dependencies(LibC LibM)
+target_link_libraries(LibC crt0 ssp system)
+add_dependencies(LibC LibM LibSystem)
diff --git a/Userland/Libraries/LibC/assert.cpp b/Userland/Libraries/LibC/assert.cpp
index 7dcd7a5258..ad9c6837d2 100644
--- a/Userland/Libraries/LibC/assert.cpp
+++ b/Userland/Libraries/LibC/assert.cpp
@@ -24,12 +24,12 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/internals.h>
+#include <syscall.h>
 #include <unistd.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/dirent.cpp b/Userland/Libraries/LibC/dirent.cpp
index 8e9701177d..504fa70367 100644
--- a/Userland/Libraries/LibC/dirent.cpp
+++ b/Userland/Libraries/LibC/dirent.cpp
@@ -26,7 +26,6 @@
 
 #include <AK/Assertions.h>
 #include <AK/StdLibExtras.h>
-#include <Kernel/API/Syscall.h>
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -34,6 +33,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <syscall.h>
 #include <unistd.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/fcntl.cpp b/Userland/Libraries/LibC/fcntl.cpp
index 7790bec113..3bd873dff7 100644
--- a/Userland/Libraries/LibC/fcntl.cpp
+++ b/Userland/Libraries/LibC/fcntl.cpp
@@ -24,11 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <string.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/ioctl.cpp b/Userland/Libraries/LibC/ioctl.cpp
index c5fee3951e..280c4d5378 100644
--- a/Userland/Libraries/LibC/ioctl.cpp
+++ b/Userland/Libraries/LibC/ioctl.cpp
@@ -24,11 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <sys/ioctl.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/mman.cpp b/Userland/Libraries/LibC/mman.cpp
index b3346d2e1f..0f01395ab5 100644
--- a/Userland/Libraries/LibC/mman.cpp
+++ b/Userland/Libraries/LibC/mman.cpp
@@ -24,11 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <mman.h>
 #include <stdio.h>
 #include <string.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/poll.cpp b/Userland/Libraries/LibC/poll.cpp
index 437ea8243a..5695ff1318 100644
--- a/Userland/Libraries/LibC/poll.cpp
+++ b/Userland/Libraries/LibC/poll.cpp
@@ -24,10 +24,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <poll.h>
 #include <sys/time.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/sched.cpp b/Userland/Libraries/LibC/sched.cpp
index 4e3643bd01..d5139cb1c5 100644
--- a/Userland/Libraries/LibC/sched.cpp
+++ b/Userland/Libraries/LibC/sched.cpp
@@ -24,9 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <sched.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/serenity.cpp b/Userland/Libraries/LibC/serenity.cpp
index 319975c653..8899a2b7df 100644
--- a/Userland/Libraries/LibC/serenity.cpp
+++ b/Userland/Libraries/LibC/serenity.cpp
@@ -24,10 +24,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <serenity.h>
 #include <string.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/serenity.h b/Userland/Libraries/LibC/serenity.h
index 70ddf295af..8860e89d14 100644
--- a/Userland/Libraries/LibC/serenity.h
+++ b/Userland/Libraries/LibC/serenity.h
@@ -106,8 +106,8 @@ int anon_create(size_t size, int options);
 
 int serenity_readlink(const char* path, size_t path_length, char* buffer, size_t buffer_size);
 
-int getkeymap(char* name_buffer, size_t name_buffer_size, u32* map, u32* shift_map, u32* alt_map, u32* altgr_map, u32* shift_altgr_map);
-int setkeymap(const char* name, const u32* map, u32* const shift_map, const u32* alt_map, const u32* altgr_map, const u32* shift_altgr_map);
+int getkeymap(char* name_buffer, size_t name_buffer_size, uint32_t* map, uint32_t* shift_map, uint32_t* alt_map, uint32_t* altgr_map, uint32_t* shift_altgr_map);
+int setkeymap(const char* name, const uint32_t* map, uint32_t* const shift_map, const uint32_t* alt_map, const uint32_t* altgr_map, const uint32_t* shift_altgr_map);
 
 #ifdef __i386__
 ALWAYS_INLINE void send_secret_data_to_userspace_emulator(uintptr_t data1, uintptr_t data2, uintptr_t data3)
diff --git a/Userland/Libraries/LibC/signal.cpp b/Userland/Libraries/LibC/signal.cpp
index 55da42a04d..cea5e149f4 100644
--- a/Userland/Libraries/LibC/signal.cpp
+++ b/Userland/Libraries/LibC/signal.cpp
@@ -25,12 +25,12 @@
  */
 
 #include <AK/Format.h>
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <errno.h>
 #include <setjmp.h>
 #include <signal.h>
 #include <string.h>
+#include <syscall.h>
 #include <unistd.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/stat.cpp b/Userland/Libraries/LibC/stat.cpp
index 5de2472dfa..16bee73b9a 100644
--- a/Userland/Libraries/LibC/stat.cpp
+++ b/Userland/Libraries/LibC/stat.cpp
@@ -24,12 +24,12 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <syscall.h>
 #include <unistd.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/stdio.cpp b/Userland/Libraries/LibC/stdio.cpp
index f96f4732ad..c1a8bca79f 100644
--- a/Userland/Libraries/LibC/stdio.cpp
+++ b/Userland/Libraries/LibC/stdio.cpp
@@ -30,7 +30,6 @@
 #include <AK/ScopedValueRollback.h>
 #include <AK/StdLibExtras.h>
 #include <AK/kmalloc.h>
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -41,6 +40,7 @@
 #include <sys/internals.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <syscall.h>
 #include <unistd.h>
 
 struct FILE {
diff --git a/Userland/Libraries/LibC/stdlib.cpp b/Userland/Libraries/LibC/stdlib.cpp
index 8a0dc247d0..56f1070e76 100644
--- a/Userland/Libraries/LibC/stdlib.cpp
+++ b/Userland/Libraries/LibC/stdlib.cpp
@@ -30,7 +30,6 @@
 #include <AK/StdLibExtras.h>
 #include <AK/Types.h>
 #include <AK/Utf8View.h>
-#include <Kernel/API/Syscall.h>
 #include <LibELF/AuxiliaryVector.h>
 #include <alloca.h>
 #include <assert.h>
@@ -45,6 +44,7 @@
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <syscall.h>
 #include <unistd.h>
 
 static void strtons(const char* str, char** endptr)
diff --git a/Userland/Libraries/LibC/sys/prctl.cpp b/Userland/Libraries/LibC/sys/prctl.cpp
index d7aa35486b..dbc4b53063 100644
--- a/Userland/Libraries/LibC/sys/prctl.cpp
+++ b/Userland/Libraries/LibC/sys/prctl.cpp
@@ -24,11 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <sys/prctl.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/sys/ptrace.cpp b/Userland/Libraries/LibC/sys/ptrace.cpp
index 9e7eb60c2a..f285ef5bb5 100644
--- a/Userland/Libraries/LibC/sys/ptrace.cpp
+++ b/Userland/Libraries/LibC/sys/ptrace.cpp
@@ -25,9 +25,9 @@
  */
 
 #include <AK/LogStream.h>
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <sys/ptrace.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/sys/select.cpp b/Userland/Libraries/LibC/sys/select.cpp
index 85c5b03d43..dfc039d12a 100644
--- a/Userland/Libraries/LibC/sys/select.cpp
+++ b/Userland/Libraries/LibC/sys/select.cpp
@@ -24,11 +24,11 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <stdio.h>
 #include <sys/select.h>
 #include <sys/time.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/sys/socket.cpp b/Userland/Libraries/LibC/sys/socket.cpp
index 95d2a015a7..a545e00021 100644
--- a/Userland/Libraries/LibC/sys/socket.cpp
+++ b/Userland/Libraries/LibC/sys/socket.cpp
@@ -25,12 +25,12 @@
  */
 
 #include <AK/Assertions.h>
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/sys/uio.cpp b/Userland/Libraries/LibC/sys/uio.cpp
index 4aad828c65..2fd6c94fe9 100644
--- a/Userland/Libraries/LibC/sys/uio.cpp
+++ b/Userland/Libraries/LibC/sys/uio.cpp
@@ -24,9 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <sys/uio.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibC/sys/wait.cpp b/Userland/Libraries/LibC/sys/wait.cpp
index 9969a8eec2..2cde5e2821 100644
--- a/Userland/Libraries/LibC/sys/wait.cpp
+++ b/Userland/Libraries/LibC/sys/wait.cpp
@@ -24,9 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <sys/wait.h>
+#include <syscall.h>
 #include <unistd.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/termios.cpp b/Userland/Libraries/LibC/termios.cpp
index 1037b0ab61..c1c4238b5c 100644
--- a/Userland/Libraries/LibC/termios.cpp
+++ b/Userland/Libraries/LibC/termios.cpp
@@ -24,7 +24,6 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <errno.h>
 #include <sys/ioctl.h>
diff --git a/Userland/Libraries/LibC/time.cpp b/Userland/Libraries/LibC/time.cpp
index e6e9f06c66..df7010c646 100644
--- a/Userland/Libraries/LibC/time.cpp
+++ b/Userland/Libraries/LibC/time.cpp
@@ -27,13 +27,13 @@
 #include <AK/String.h>
 #include <AK/StringBuilder.h>
 #include <AK/Time.h>
-#include <Kernel/API/Syscall.h>
 #include <assert.h>
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/time.h>
 #include <sys/times.h>
+#include <syscall.h>
 #include <time.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/times.cpp b/Userland/Libraries/LibC/times.cpp
index 012dfc7d70..78400a6294 100644
--- a/Userland/Libraries/LibC/times.cpp
+++ b/Userland/Libraries/LibC/times.cpp
@@ -24,9 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <sys/times.h>
+#include <syscall.h>
 
 clock_t times(struct tms* buf)
 {
diff --git a/Userland/Libraries/LibC/unistd.cpp b/Userland/Libraries/LibC/unistd.cpp
index b87220f25d..40544d56f0 100644
--- a/Userland/Libraries/LibC/unistd.cpp
+++ b/Userland/Libraries/LibC/unistd.cpp
@@ -27,7 +27,6 @@
 #include <AK/ScopedValueRollback.h>
 #include <AK/String.h>
 #include <AK/Vector.h>
-#include <Kernel/API/Syscall.h>
 #include <alloca.h>
 #include <assert.h>
 #include <errno.h>
@@ -42,6 +41,7 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/types.h>
+#include <syscall.h>
 #include <termios.h>
 #include <time.h>
 #include <unistd.h>
diff --git a/Userland/Libraries/LibC/utime.cpp b/Userland/Libraries/LibC/utime.cpp
index 501d7f06c2..a75908d80a 100644
--- a/Userland/Libraries/LibC/utime.cpp
+++ b/Userland/Libraries/LibC/utime.cpp
@@ -24,9 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <string.h>
+#include <syscall.h>
 #include <utime.h>
 
 extern "C" {
diff --git a/Userland/Libraries/LibC/utsname.cpp b/Userland/Libraries/LibC/utsname.cpp
index 23d10ee7e9..c0b9484f1f 100644
--- a/Userland/Libraries/LibC/utsname.cpp
+++ b/Userland/Libraries/LibC/utsname.cpp
@@ -24,9 +24,9 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <sys/utsname.h>
+#include <syscall.h>
 
 extern "C" {
 
diff --git a/Userland/Libraries/LibCore/AnonymousBuffer.cpp b/Userland/Libraries/LibCore/AnonymousBuffer.cpp
index 40853ff732..8f6b1bedad 100644
--- a/Userland/Libraries/LibCore/AnonymousBuffer.cpp
+++ b/Userland/Libraries/LibCore/AnonymousBuffer.cpp
@@ -33,7 +33,6 @@
 #include <sys/mman.h>
 
 #if defined(__serenity__)
-#    include <Kernel/API/Syscall.h>
 #    include <serenity.h>
 #endif
 
diff --git a/Userland/Libraries/LibCore/File.cpp b/Userland/Libraries/LibCore/File.cpp
index 44ba8d41d7..38da00fb81 100644
--- a/Userland/Libraries/LibCore/File.cpp
+++ b/Userland/Libraries/LibCore/File.cpp
@@ -25,7 +25,6 @@
  */
 
 #ifdef __serenity__
-#    include <Kernel/API/Syscall.h>
 #    include <serenity.h>
 #endif
 #include <AK/ScopeGuard.h>
diff --git a/Userland/Libraries/LibELF/DynamicLinker.cpp b/Userland/Libraries/LibELF/DynamicLinker.cpp
index dd2f61a4ef..92b790eb54 100644
--- a/Userland/Libraries/LibELF/DynamicLinker.cpp
+++ b/Userland/Libraries/LibELF/DynamicLinker.cpp
@@ -31,7 +31,6 @@
 #include <AK/LexicalPath.h>
 #include <AK/LogStream.h>
 #include <AK/ScopeGuard.h>
-#include <Kernel/API/Syscall.h>
 #include <LibC/mman.h>
 #include <LibC/stdio.h>
 #include <LibC/sys/internals.h>
@@ -45,6 +44,7 @@
 #include <fcntl.h>
 #include <string.h>
 #include <sys/types.h>
+#include <syscall.h>
 
 namespace ELF {
 
@@ -216,7 +216,7 @@ static NonnullRefPtr<DynamicLoader> commit_elf(const String& name)
     auto object = loader->load_stage_3(RTLD_GLOBAL | RTLD_LAZY, g_total_tls_size);
     ASSERT(object);
 
-    if (name.is_one_of("libc.so", "libpthread.so", "/bin/UserspaceEmulator")) {
+    if (name == "libsystem.so") {
         if (syscall(SC_msyscall, object->base_address().as_ptr())) {
             ASSERT_NOT_REACHED();
         }
diff --git a/Userland/Libraries/LibKeyboard/CharacterMap.cpp b/Userland/Libraries/LibKeyboard/CharacterMap.cpp
index 011a935ffc..cf5771d67f 100644
--- a/Userland/Libraries/LibKeyboard/CharacterMap.cpp
+++ b/Userland/Libraries/LibKeyboard/CharacterMap.cpp
@@ -26,7 +26,6 @@
 
 #include "CharacterMap.h"
 #include <AK/StringBuilder.h>
-#include <Kernel/API/Syscall.h>
 #include <LibKeyboard/CharacterMapFile.h>
 
 #ifndef KERNEL
diff --git a/Userland/Libraries/LibPthread/CMakeLists.txt b/Userland/Libraries/LibPthread/CMakeLists.txt
index c8644e0868..c28f072b5e 100644
--- a/Userland/Libraries/LibPthread/CMakeLists.txt
+++ b/Userland/Libraries/LibPthread/CMakeLists.txt
@@ -4,5 +4,5 @@ set(SOURCES
 )
 
 serenity_libc(LibPthread pthread)
-target_link_libraries(LibPthread LibC)
+target_link_libraries(LibPthread LibC LibSystem)
 target_include_directories(LibPthread PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/Userland/Libraries/LibPthread/pthread.cpp b/Userland/Libraries/LibPthread/pthread.cpp
index b366b773b5..b4b5240efa 100644
--- a/Userland/Libraries/LibPthread/pthread.cpp
+++ b/Userland/Libraries/LibPthread/pthread.cpp
@@ -28,7 +28,6 @@
 #include <AK/Atomic.h>
 #include <AK/Debug.h>
 #include <AK/StdLibExtras.h>
-#include <Kernel/API/Syscall.h>
 #include <limits.h>
 #include <pthread.h>
 #include <serenity.h>
@@ -36,6 +35,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <sys/mman.h>
+#include <syscall.h>
 #include <time.h>
 #include <unistd.h>
 
diff --git a/Userland/Libraries/LibSystem/CMakeLists.txt b/Userland/Libraries/LibSystem/CMakeLists.txt
new file mode 100644
index 0000000000..f93dbe2c9b
--- /dev/null
+++ b/Userland/Libraries/LibSystem/CMakeLists.txt
@@ -0,0 +1,7 @@
+set(SOURCES
+    syscall.cpp
+)
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -nostdlib")
+serenity_libc(LibSystem system)
+target_include_directories(LibSystem PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
diff --git a/Userland/Libraries/LibSystem/syscall.cpp b/Userland/Libraries/LibSystem/syscall.cpp
new file mode 100644
index 0000000000..081d3709e7
--- /dev/null
+++ b/Userland/Libraries/LibSystem/syscall.cpp
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Kernel/API/Syscall.h>
+#include <LibSystem/syscall.h>
+
+extern "C" {
+
+uintptr_t syscall0(uintptr_t function)
+{
+    return Syscall::invoke((Syscall::Function)function);
+}
+
+uintptr_t syscall1(uintptr_t function, uintptr_t arg0)
+{
+    return Syscall::invoke((Syscall::Function)function, arg0);
+}
+
+uintptr_t syscall2(uintptr_t function, uintptr_t arg0, uintptr_t arg1)
+{
+    return Syscall::invoke((Syscall::Function)function, arg0, arg1);
+}
+
+uintptr_t syscall3(uintptr_t function, uintptr_t arg0, uintptr_t arg1, uintptr_t arg2)
+{
+    return Syscall::invoke((Syscall::Function)function, arg0, arg1, arg2);
+}
+}
diff --git a/Userland/Libraries/LibSystem/syscall.h b/Userland/Libraries/LibSystem/syscall.h
new file mode 100644
index 0000000000..68aea02258
--- /dev/null
+++ b/Userland/Libraries/LibSystem/syscall.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <Kernel/API/Syscall.h>
+#include <sys/types.h>
+
+extern "C" {
+
+uintptr_t syscall0(uintptr_t function);
+uintptr_t syscall1(uintptr_t function, uintptr_t arg0);
+uintptr_t syscall2(uintptr_t function, uintptr_t arg0, uintptr_t arg1);
+uintptr_t syscall3(uintptr_t function, uintptr_t arg0, uintptr_t arg1, uintptr_t arg2);
+}
+
+#ifdef __cplusplus
+
+inline uintptr_t syscall(auto function)
+{
+    return syscall0(function);
+}
+
+inline uintptr_t syscall(auto function, auto arg0)
+{
+    return syscall1((uintptr_t)function, (uintptr_t)arg0);
+}
+
+inline uintptr_t syscall(auto function, auto arg0, auto arg1)
+{
+    return syscall2((uintptr_t)function, (uintptr_t)arg0, (uintptr_t)arg1);
+}
+
+inline uintptr_t syscall(auto function, auto arg0, auto arg1, auto arg2)
+{
+    return syscall3((uintptr_t)function, (uintptr_t)arg0, (uintptr_t)arg1, (uintptr_t)arg2);
+}
+
+#endif
diff --git a/Userland/Tests/Kernel/invalid-any-pointer-assert.cpp b/Userland/Tests/Kernel/invalid-any-pointer-assert.cpp
index afdd539e73..0491b79c91 100644
--- a/Userland/Tests/Kernel/invalid-any-pointer-assert.cpp
+++ b/Userland/Tests/Kernel/invalid-any-pointer-assert.cpp
@@ -25,9 +25,9 @@
  */
 
 #include <AK/Format.h>
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <stdio.h>
+#include <syscall.h>
 
 int main()
 {
diff --git a/Userland/Tests/Kernel/invalid-path-pointer-assert.cpp b/Userland/Tests/Kernel/invalid-path-pointer-assert.cpp
index fe503753d1..85001f8dd6 100644
--- a/Userland/Tests/Kernel/invalid-path-pointer-assert.cpp
+++ b/Userland/Tests/Kernel/invalid-path-pointer-assert.cpp
@@ -24,10 +24,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <stdio.h>
 #include <sys/stat.h>
+#include <syscall.h>
 
 int main()
 {
diff --git a/Userland/Utilities/crash.cpp b/Userland/Utilities/crash.cpp
index 7e96360ddf..188eb690aa 100644
--- a/Userland/Utilities/crash.cpp
+++ b/Userland/Utilities/crash.cpp
@@ -27,13 +27,13 @@
 
 #include <AK/Function.h>
 #include <AK/String.h>
-#include <Kernel/API/Syscall.h>
 #include <Kernel/IO.h>
 #include <LibCore/ArgsParser.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
+#include <syscall.h>
 
 #pragma GCC optimize("O0")
 
diff --git a/Userland/Utilities/functrace.cpp b/Userland/Utilities/functrace.cpp
index dcb2d046b3..01059090f9 100644
--- a/Userland/Utilities/functrace.cpp
+++ b/Userland/Utilities/functrace.cpp
@@ -32,7 +32,6 @@
 #include <AK/NonnullOwnPtr.h>
 #include <AK/StringBuilder.h>
 #include <AK/kmalloc.h>
-#include <Kernel/API/Syscall.h>
 #include <LibC/sys/arch/i386/regs.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/File.h>
@@ -45,6 +44,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <syscall.h>
 #include <unistd.h>
 
 static OwnPtr<Debug::DebugSession> g_debug_session;
diff --git a/Userland/Utilities/purge.cpp b/Userland/Utilities/purge.cpp
index 95257ec563..efd3e7a486 100644
--- a/Userland/Utilities/purge.cpp
+++ b/Userland/Utilities/purge.cpp
@@ -24,7 +24,6 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <LibCore/ArgsParser.h>
 #include <serenity.h>
 #include <stdio.h>
diff --git a/Userland/Utilities/strace.cpp b/Userland/Utilities/strace.cpp
index e915e7d3f2..64d005cfbb 100644
--- a/Userland/Utilities/strace.cpp
+++ b/Userland/Utilities/strace.cpp
@@ -27,7 +27,6 @@
 #include <AK/Assertions.h>
 #include <AK/LogStream.h>
 #include <AK/Types.h>
-#include <Kernel/API/Syscall.h>
 #include <LibC/sys/arch/i386/regs.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/File.h>
@@ -37,6 +36,7 @@
 #include <string.h>
 #include <sys/ptrace.h>
 #include <sys/wait.h>
+#include <syscall.h>
 #include <unistd.h>
 
 static int g_pid = -1;
diff --git a/Userland/Utilities/syscall.cpp b/Userland/Utilities/syscall.cpp
index fcb7862e3c..d80692ffec 100644
--- a/Userland/Utilities/syscall.cpp
+++ b/Userland/Utilities/syscall.cpp
@@ -24,13 +24,13 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <Kernel/API/Syscall.h>
 #include <errno.h>
 #include <getopt.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <syscall.h>
 #include <unistd.h>
 
 #if !defined __ENUMERATE_SYSCALL