[libc] Move the x86_64 syscall functions to OSUtil.

Reviewed By: michaelrj, lntue

Differential Revision: https://reviews.llvm.org/D116177

38 files changed, 106 insertions, 88 deletions

diff --git a/libc/config/linux/CMakeLists.txt b/libc/config/linux/CMakeLists.txt
index e3a0018..bc42557 100644
--- a/libc/config/linux/CMakeLists.txt
+++ b/libc/config/linux/CMakeLists.txt
@@ -1,15 +1,3 @@
-add_gen_header(
-  linux_syscall_h
-  DEF_FILE syscall.h.def
-  GEN_HDR syscall.h
-  PARAMS
-    inline_syscalls=${LIBC_TARGET_ARCHITECTURE}/syscall.h.inc
-  DATA_FILES
-    ${LIBC_TARGET_ARCHITECTURE}/syscall.h.inc
-  DEPENDS
-    libc.src.__support.common
-)
-
 add_header(
   app_h
   HDR
diff --git a/libc/loader/linux/x86_64/CMakeLists.txt b/libc/loader/linux/x86_64/CMakeLists.txt
index ceaa94e..75b8a23 100644
--- a/libc/loader/linux/x86_64/CMakeLists.txt
+++ b/libc/loader/linux/x86_64/CMakeLists.txt
@@ -3,9 +3,9 @@ add_loader_object(
   SRC
     start.cpp
   DEPENDS
-    libc.config.linux.linux_syscall_h
     libc.config.linux.app_h
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
     libc.src.string.memcpy
     libc.src.sys.mman.mmap
   COMPILE_OPTIONS
diff --git a/libc/loader/linux/x86_64/start.cpp b/libc/loader/linux/x86_64/start.cpp
index 320fda9..55ae003 100644
--- a/libc/loader/linux/x86_64/start.cpp
+++ b/libc/loader/linux/x86_64/start.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/app.h"
-#include "config/linux/syscall.h"
 #include "include/sys/mman.h"
 #include "include/sys/syscall.h"
+#include "src/__support/OSUtil/syscall.h"
 #include "src/string/memcpy.h"
 #include "src/sys/mman/mmap.h"
 
diff --git a/libc/src/__support/OSUtil/CMakeLists.txt b/libc/src/__support/OSUtil/CMakeLists.txt
index b0f7ac8..028a9c0 100644
--- a/libc/src/__support/OSUtil/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/CMakeLists.txt
@@ -5,6 +5,7 @@ add_header_library(
   HDRS
     io.h
     quick_exit.h
+    syscall.h
   DEPENDS
     libc.src.__support.OSUtil.linux.linux_util
 )
diff --git a/libc/src/__support/OSUtil/linux/CMakeLists.txt b/libc/src/__support/OSUtil/linux/CMakeLists.txt
index 3828614..4b0f5d7 100644
--- a/libc/src/__support/OSUtil/linux/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/linux/CMakeLists.txt
@@ -1,10 +1,12 @@
+add_subdirectory(x86_64)
+
 add_header_library(
   linux_util
   HDRS
     io.h
     quick_exit.h
+    syscall.h
   DEPENDS
-    libc.config.linux.linux_syscall_h
-    libc.include.sys_syscall
-    libc.src.string.string_utils
+    .x86_64.linux_x86_64_util
+    libc.src.__support.common
 )
diff --git a/libc/src/__support/OSUtil/linux/io.h b/libc/src/__support/OSUtil/linux/io.h
index 5aaa544..71830476 100644
--- a/libc/src/__support/OSUtil/linux/io.h
+++ b/libc/src/__support/OSUtil/linux/io.h
@@ -9,9 +9,9 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_IO_H
 #define LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_IO_H
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h" // For syscall numbers.
 #include "src/string/string_utils.h"
+#include "syscall.h" // For internal syscall function.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/__support/OSUtil/linux/quick_exit.h b/libc/src/__support/OSUtil/linux/quick_exit.h
index 932959d..eb9d86f 100644
--- a/libc/src/__support/OSUtil/linux/quick_exit.h
+++ b/libc/src/__support/OSUtil/linux/quick_exit.h
@@ -9,8 +9,8 @@
 #ifndef LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_QUICK_EXIT_H
 #define LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_QUICK_EXIT_H
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h" // For syscall numbers.
+#include "syscall.h"             // For internal syscall function.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/__support/OSUtil/linux/syscall.h b/libc/src/__support/OSUtil/linux/syscall.h
new file mode 100644
index 0000000..754883e
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall.h
@@ -0,0 +1,18 @@
+//===----------------------- Linux syscalls ---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_SYSCALL_H
+#define LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_SYSCALL_H
+
+#include "src/__support/architectures.h"
+
+#ifdef LLVM_LIBC_ARCH_X86_64
+#include "x86_64/syscall.h"
+#endif
+
+#endif // LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_SYSCALL_H
diff --git a/libc/src/__support/OSUtil/linux/x86_64/CMakeLists.txt b/libc/src/__support/OSUtil/linux/x86_64/CMakeLists.txt
new file mode 100644
index 0000000..a7f2d74e6
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/x86_64/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_header_library(
+  linux_x86_64_util
+  HDRS
+    syscall.h
+  DEPENDS
+    libc.src.__support.common
+)
diff --git a/libc/config/linux/x86_64/syscall.h.inc b/libc/src/__support/OSUtil/linux/x86_64/syscall.h
index ee3b5e5..77d1398 100644
--- a/libc/config/linux/x86_64/syscall.h.inc
+++ b/libc/src/__support/OSUtil/linux/x86_64/syscall.h
@@ -1,4 +1,4 @@
-//===------------ inline implementation of x86_64 syscalls ----------------===//
+//===---------- inline implementation of x86_64 syscalls ----------* C++ *-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,7 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-%%begin()
+#ifndef LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_X86_64_SYSCALL_H
+#define LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_X86_64_SYSCALL_H
 
 #include "src/__support/common.h"
 
@@ -100,7 +101,8 @@ __attribute__((always_inline)) inline long syscall(long __number, Ts... ts) {
   return syscall(__number, (long)ts...);
 }
 
-
 #undef SYSCALL_CLOBBER_LIST
 
 } // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_SUPPORT_OSUTIL_LINUX_X86_64_SYSCALL_H
diff --git a/libc/config/linux/syscall.h.def b/libc/src/__support/OSUtil/syscall.h
index 0daceaf..b113727 100644
--- a/libc/config/linux/syscall.h.def
+++ b/libc/src/__support/OSUtil/syscall.h
@@ -6,9 +6,11 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_CONFIG_LINUX_SYSCALL_H
-#define LLVM_LIBC_CONFIG_LINUX_SYSCALL_H
+#ifndef LLVM_LIBC_SRC_SUPPORT_OSUTIL_SYSCALL_H
+#define LLVM_LIBC_SRC_SUPPORT_OSUTIL_SYSCALL_H
 
-%%include_file(${inline_syscalls})
+#ifdef __unix__
+#include "linux/syscall.h"
+#endif
 
-#endif // LLVM_LIBC_CONFIG_LINUX_SYSCALL_H
+#endif // LLVM_LIBC_SRC_SUPPORT_OSUTIL_SYSCALL_H
diff --git a/libc/src/assert/CMakeLists.txt b/libc/src/assert/CMakeLists.txt
index 36123cc..7f82017 100644
--- a/libc/src/assert/CMakeLists.txt
+++ b/libc/src/assert/CMakeLists.txt
@@ -8,7 +8,7 @@ add_entrypoint_object(
   DEPENDS
     # These two dependencies are temporary and should be replaced by fprintf
     # later.
-    libc.config.linux.linux_syscall_h
+    libc.src.__support.OSUtil.osutil
     libc.include.sys_syscall
     libc.src.stdlib.abort
 )
diff --git a/libc/src/assert/__assert_fail.cpp b/libc/src/assert/__assert_fail.cpp
index 0fe2ca6..93c176a 100644
--- a/libc/src/assert/__assert_fail.cpp
+++ b/libc/src/assert/__assert_fail.cpp
@@ -10,8 +10,8 @@
 #include "src/stdlib/abort.h"
 
 // These includes are temporary.
-#include "config/linux/syscall.h" // For internal syscall function.
 #include "include/sys/syscall.h"  // For syscall numbers.
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/linux/CMakeLists.txt b/libc/src/signal/linux/CMakeLists.txt
index fc4a7aa..419146f5 100644
--- a/libc/src/signal/linux/CMakeLists.txt
+++ b/libc/src/signal/linux/CMakeLists.txt
@@ -7,9 +7,9 @@ add_entrypoint_object(
     signal.h
     ../raise.h
   DEPENDS
-    libc.config.linux.linux_syscall_h
     libc.include.signal
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
 )
 
 add_object_library(
@@ -25,8 +25,8 @@ add_object_library(
     # asan creates asan.module_ctor which uses stack space, causing warnings.
     -fno-sanitize=address
   DEPENDS
-    libc.config.linux.linux_syscall_h
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
 )
 
 add_entrypoint_object(
@@ -38,9 +38,9 @@ add_entrypoint_object(
     ../sigaction.h
   DEPENDS
     .__restore
-    libc.config.linux.linux_syscall_h
     libc.include.signal
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
     libc.src.errno.__errno_location
 )
 
@@ -52,9 +52,9 @@ add_entrypoint_object(
     signal.h
     ../sigprocmask.h
   DEPENDS
-    libc.config.linux.linux_syscall_h
     libc.include.signal
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
     libc.src.errno.__errno_location
 )
 
diff --git a/libc/src/signal/linux/__restore.cpp b/libc/src/signal/linux/__restore.cpp
index 8ce848f..c648ddb 100644
--- a/libc/src/signal/linux/__restore.cpp
+++ b/libc/src/signal/linux/__restore.cpp
@@ -10,8 +10,8 @@
 // strongly control the options this file is compiled with. __restore_rt cannot
 // make any stack allocations so we must ensure this.
 
-#include "config/linux/syscall.h"
 #include "include/sys/syscall.h"
+#include "src/__support/OSUtil/syscall.h"
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/linux/signal.h b/libc/src/signal/linux/signal.h
index a59a56c..fd312d7 100644
--- a/libc/src/signal/linux/signal.h
+++ b/libc/src/signal/linux/signal.h
@@ -9,8 +9,8 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_LINUX_SIGNAL_H
 #define LLVM_LIBC_SRC_SIGNAL_LINUX_SIGNAL_H
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 
 #include "include/signal.h"
 
diff --git a/libc/src/stdlib/linux/CMakeLists.txt b/libc/src/stdlib/linux/CMakeLists.txt
index 27e00a3..c5130c1 100644
--- a/libc/src/stdlib/linux/CMakeLists.txt
+++ b/libc/src/stdlib/linux/CMakeLists.txt
@@ -6,6 +6,6 @@ add_entrypoint_object(
     ../_Exit.h
   DEPENDS
     libc.include.sys_syscall
-    libc.config.linux.linux_syscall_h
     libc.include.stdlib
+    libc.src.__support.OSUtil.osutil
 )
diff --git a/libc/src/stdlib/linux/_Exit.cpp b/libc/src/stdlib/linux/_Exit.cpp
index 7fdd60f..51b0a48 100644
--- a/libc/src/stdlib/linux/_Exit.cpp
+++ b/libc/src/stdlib/linux/_Exit.cpp
@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
 
 #include "src/stdlib/_Exit.h"
diff --git a/libc/src/sys/mman/linux/CMakeLists.txt b/libc/src/sys/mman/linux/CMakeLists.txt
index 7bf7c2f..949d965 100644
--- a/libc/src/sys/mman/linux/CMakeLists.txt
+++ b/libc/src/sys/mman/linux/CMakeLists.txt
@@ -5,9 +5,9 @@ add_entrypoint_object(
   HDRS
     ../mmap.h
   DEPENDS
-    libc.config.linux.linux_syscall_h
     libc.include.sys_mman
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
     libc.src.errno.__errno_location
 )
 
@@ -18,8 +18,8 @@ add_entrypoint_object(
   HDRS
     ../munmap.h
   DEPENDS
-    libc.config.linux.linux_syscall_h
     libc.include.sys_mman
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
     libc.src.errno.__errno_location
 )
diff --git a/libc/src/sys/mman/linux/mmap.cpp b/libc/src/sys/mman/linux/mmap.cpp
index 31e114a..0447ef1 100644
--- a/libc/src/sys/mman/linux/mmap.cpp
+++ b/libc/src/sys/mman/linux/mmap.cpp
@@ -8,8 +8,8 @@
 
 #include "src/sys/mman/mmap.h"
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
 
diff --git a/libc/src/sys/mman/linux/munmap.cpp b/libc/src/sys/mman/linux/munmap.cpp
index fd89773..7801a63 100644
--- a/libc/src/sys/mman/linux/munmap.cpp
+++ b/libc/src/sys/mman/linux/munmap.cpp
@@ -8,8 +8,8 @@
 
 #include "src/sys/mman/munmap.h"
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
 
diff --git a/libc/src/threads/linux/CMakeLists.txt b/libc/src/threads/linux/CMakeLists.txt
index e9fc8d2..fcc3381 100644
--- a/libc/src/threads/linux/CMakeLists.txt
+++ b/libc/src/threads/linux/CMakeLists.txt
@@ -16,9 +16,9 @@ add_entrypoint_object(
     ../call_once.h
   DEPENDS
     .threads_utils
-    libc.config.linux.linux_syscall_h
     libc.include.sys_syscall
     libc.include.threads
+    libc.src.__support.OSUtil.osutil
 )
 
 add_header_library(
@@ -30,9 +30,9 @@ add_header_library(
     Thread.h
   DEPENDS
     .thread_start_args_h
-    libc.config.linux.linux_syscall_h
     libc.include.sys_syscall
     libc.include.threads
+    libc.src.__support.OSUtil.osutil
 )
 
 add_entrypoint_object(
@@ -43,11 +43,11 @@ add_entrypoint_object(
     ../thrd_create.h
   DEPENDS
     .threads_utils
-    libc.config.linux.linux_syscall_h
     libc.include.errno
     libc.include.sys_syscall
     libc.include.threads
     libc.src.__support.common
+    libc.src.__support.OSUtil.osutil
     libc.src.errno.__errno_location
     libc.src.sys.mman.mmap
   COMPILE_OPTIONS
@@ -64,11 +64,11 @@ add_entrypoint_object(
     ../thrd_join.h
   DEPENDS
     .threads_utils
-    libc.config.linux.linux_syscall_h
     libc.include.sys_syscall
     libc.include.threads
-    libc.src.sys.mman.munmap
     libc.src.__support.common
+    libc.src.__support.OSUtil.osutil
+    libc.src.sys.mman.munmap
 )
 
 add_entrypoint_object(
diff --git a/libc/src/threads/linux/CndVar.h b/libc/src/threads/linux/CndVar.h
index 5d9ced5..7e531c8 100644
--- a/libc/src/threads/linux/CndVar.h
+++ b/libc/src/threads/linux/CndVar.h
@@ -12,9 +12,9 @@
 #include "Futex.h"
 #include "Mutex.h"
 
-#include "config/linux/syscall.h" // For syscall functions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For values like thrd_success etc.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "include/threads.h"              // For values like thrd_success etc.
+#include "src/__support/OSUtil/syscall.h" // For syscall functions.
 
 #include <linux/futex.h> // For futex operations.
 #include <stdatomic.h>   // For atomic operations
diff --git a/libc/src/threads/linux/Mutex.h b/libc/src/threads/linux/Mutex.h
index f6033c9..a7b06d4 100644
--- a/libc/src/threads/linux/Mutex.h
+++ b/libc/src/threads/linux/Mutex.h
@@ -11,9 +11,9 @@
 
 #include "Futex.h"
 
-#include "config/linux/syscall.h" // For syscall functions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For values like thrd_success etc.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "include/threads.h"              // For values like thrd_success etc.
+#include "src/__support/OSUtil/syscall.h" // For syscall functions.
 
 #include <linux/futex.h> // For futex operations.
 #include <stdatomic.h>
diff --git a/libc/src/threads/linux/call_once.cpp b/libc/src/threads/linux/call_once.cpp
index 1bcb46f..9b96646 100644
--- a/libc/src/threads/linux/call_once.cpp
+++ b/libc/src/threads/linux/call_once.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/threads/call_once.h"
-#include "config/linux/syscall.h" // For syscall functions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For call_once related type definition.
+#include "include/sys/syscall.h" // For syscall numbers.
+#include "include/threads.h"     // For call_once related type definition.
+#include "src/__support/OSUtil/syscall.h" // For syscall functions.
 #include "src/__support/common.h"
 #include "src/threads/linux/Futex.h"
 
diff --git a/libc/src/threads/linux/thrd_create.cpp b/libc/src/threads/linux/thrd_create.cpp
index f2464d4..5421c96 100644
--- a/libc/src/threads/linux/thrd_create.cpp
+++ b/libc/src/threads/linux/thrd_create.cpp
@@ -7,11 +7,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/threads/thrd_create.h"
-#include "config/linux/syscall.h" // For syscall function.
-#include "include/errno.h"        // For E* error values.
-#include "include/sys/mman.h"     // For PROT_* and MAP_* definitions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For thrd_* type definitions.
+#include "include/errno.h"                // For E* error values.
+#include "include/sys/mman.h"             // For PROT_* and MAP_* definitions.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "include/threads.h"              // For thrd_* type definitions.
+#include "src/__support/OSUtil/syscall.h" // For syscall function.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
 #include "src/sys/mman/mmap.h"
diff --git a/libc/src/threads/linux/thrd_join.cpp b/libc/src/threads/linux/thrd_join.cpp
index 3c77949..f55f5a3 100644
--- a/libc/src/threads/linux/thrd_join.cpp
+++ b/libc/src/threads/linux/thrd_join.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/threads/thrd_join.h"
-#include "config/linux/syscall.h" // For syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For thrd_* type definitions.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "include/threads.h"              // For thrd_* type definitions.
+#include "src/__support/OSUtil/syscall.h" // For syscall function.
 #include "src/__support/common.h"
 #include "src/sys/mman/munmap.h"
 #include "src/threads/linux/Futex.h"
diff --git a/libc/src/unistd/linux/CMakeLists.txt b/libc/src/unistd/linux/CMakeLists.txt
index bd2cba7..1c3fdf1 100644
--- a/libc/src/unistd/linux/CMakeLists.txt
+++ b/libc/src/unistd/linux/CMakeLists.txt
@@ -6,7 +6,7 @@ add_entrypoint_object(
     ../write.h
   DEPENDS
     libc.include.unistd
-    libc.config.linux.linux_syscall_h
     libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
     libc.src.errno.__errno_location
 )
diff --git a/libc/src/unistd/linux/write.cpp b/libc/src/unistd/linux/write.cpp
index de0efb9..3554e30 100644
--- a/libc/src/unistd/linux/write.cpp
+++ b/libc/src/unistd/linux/write.cpp
@@ -8,8 +8,8 @@
 
 #include "src/unistd/write.h"
 
-#include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include "include/sys/syscall.h"          // For syscall numbers.
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
 
diff --git a/libc/test/CMakeLists.txt b/libc/test/CMakeLists.txt
index 3cf1f8d..850d693 100644
--- a/libc/test/CMakeLists.txt
+++ b/libc/test/CMakeLists.txt
@@ -18,6 +18,5 @@ if(NOT LLVM_LIBC_FULL_BUILD)
   return()
 endif()
 
-add_subdirectory(config)
 add_subdirectory(integration)
 add_subdirectory(loader)
diff --git a/libc/test/config/CMakeLists.txt b/libc/test/config/CMakeLists.txt
deleted file mode 100644
index 52824d2..0000000
--- a/libc/test/config/CMakeLists.txt
+++ /dev/null
@@ -1 +0,0 @@
-add_subdirectory(${LIBC_TARGET_OS})
diff --git a/libc/test/config/linux/CMakeLists.txt b/libc/test/config/linux/CMakeLists.txt
deleted file mode 100644
index b449a33..0000000
--- a/libc/test/config/linux/CMakeLists.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-add_libc_testsuite(libc_linux_tests)
-
-if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_ARCHITECTURE})
-  add_subdirectory(${LIBC_TARGET_ARCHITECTURE})
-endif()
diff --git a/libc/test/config/linux/x86_64/CMakeLists.txt b/libc/test/config/linux/x86_64/CMakeLists.txt
deleted file mode 100644
index 0436736..0000000
--- a/libc/test/config/linux/x86_64/CMakeLists.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-add_libc_unittest(
-  libc_linux_x86_64_syscall_unittest
-  SUITE libc_linux_tests
-  SRCS syscall_test.cpp
-  DEPENDS
-   libc.config.linux.linux_syscall_h
-)
diff --git a/libc/test/src/__support/CMakeLists.txt b/libc/test/src/__support/CMakeLists.txt
index d2367ef..20d0e2d 100644
--- a/libc/test/src/__support/CMakeLists.txt
+++ b/libc/test/src/__support/CMakeLists.txt
@@ -48,3 +48,5 @@ add_custom_command(TARGET libc_str_to_float_comparison_test
                    DEPENDS ${float_test_file}
                    COMMENT "Test the strtof and strtod implementations against precomputed results." 
                    VERBATIM)
+
+add_subdirectory(OSUtil)
diff --git a/libc/test/src/__support/OSUtil/CMakeLists.txt b/libc/test/src/__support/OSUtil/CMakeLists.txt
new file mode 100644
index 0000000..494218b
--- /dev/null
+++ b/libc/test/src/__support/OSUtil/CMakeLists.txt
@@ -0,0 +1,3 @@
+add_libc_testsuite(libc_osutil_tests)
+
+add_subdirectory(linux)
diff --git a/libc/test/src/__support/OSUtil/linux/CMakeLists.txt b/libc/test/src/__support/OSUtil/linux/CMakeLists.txt
new file mode 100644
index 0000000..7e2608e
--- /dev/null
+++ b/libc/test/src/__support/OSUtil/linux/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(x86_64)
diff --git a/libc/test/src/__support/OSUtil/linux/x86_64/CMakeLists.txt b/libc/test/src/__support/OSUtil/linux/x86_64/CMakeLists.txt
new file mode 100644
index 0000000..b6f57eb
--- /dev/null
+++ b/libc/test/src/__support/OSUtil/linux/x86_64/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_libc_unittest(
+  syscall_unittest
+  SUITE libc_osutil_tests
+  SRCS syscall_test.cpp
+  DEPENDS
+   libc.src.__support.OSUtil.osutil
+)
diff --git a/libc/test/config/linux/x86_64/syscall_test.cpp b/libc/test/src/__support/OSUtil/linux/x86_64/syscall_test.cpp
index eb2205a..2f9816e 100644
--- a/libc/test/config/linux/x86_64/syscall_test.cpp
+++ b/libc/test/src/__support/OSUtil/linux/x86_64/syscall_test.cpp
@@ -6,10 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "config/linux/syscall.h"
-#include "utils/UnitTest/Test.h"
-
 #include "src/__support/CPP/Functional.h"
+#include "src/__support/OSUtil/syscall.h"
+#include "utils/UnitTest/Test.h"
 
 TEST(LlvmLibcX86_64_SyscallTest, APITest) {
   // We only do a signature test here. Actual functionality tests are