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+/* Assembly code template for system call stubs.
+ Copyright (C) 2009-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* The real guts of this work are in the macros defined in the
+ machine- and kernel-specific sysdep.h header file. When we
+ are defining a cancellable system call, the sysdep-cancel.h
+ versions of those macros are what we really use.
+
+ Each system call's object is built by a rule in sysd-syscalls
+ generated by make-syscalls.sh that #include's this file after
+ defining a few macros:
+ SYSCALL_NAME syscall name
+ SYSCALL_NARGS number of arguments this call takes
+ SYSCALL_SYMBOL primary symbol name
+ SYSCALL_CANCELLABLE 1 if the call is a cancelation point
+ SYSCALL_NOERRNO 1 to define a no-errno version (see below)
+ SYSCALL_ERRVAL 1 to define an error-value version (see below)
+
+ We used to simply pipe the correct three lines below through cpp into
+ the assembler. The main reason to have this file instead is so that
+ stub objects can be assembled with -g and get source line information
+ that leads a user back to a source file and these fine comments. The
+ average user otherwise has a hard time knowing which "syscall-like"
+ functions in libc are plain stubs and which have nontrivial C wrappers.
+ Some versions of the "plain" stub generation macros are more than a few
+ instructions long and the untrained eye might not distinguish them from
+ some compiled code that inexplicably lacks source line information. */
+
+#if SYSCALL_CANCELLABLE
+# include <sysdep-cancel.h>
+#else
+# include <sysdep.h>
+#endif
+
+/* This indirection is needed so that SYMBOL gets macro-expanded. */
+#define syscall_hidden_def(SYMBOL) hidden_def (SYMBOL)
+
+#define T_PSEUDO(SYMBOL, NAME, N) PSEUDO (SYMBOL, NAME, N)
+#define T_PSEUDO_NOERRNO(SYMBOL, NAME, N) PSEUDO_NOERRNO (SYMBOL, NAME, N)
+#define T_PSEUDO_ERRVAL(SYMBOL, NAME, N) PSEUDO_ERRVAL (SYMBOL, NAME, N)
+#define T_PSEUDO_END(SYMBOL) PSEUDO_END (SYMBOL)
+#define T_PSEUDO_END_NOERRNO(SYMBOL) PSEUDO_END_NOERRNO (SYMBOL)
+#define T_PSEUDO_END_ERRVAL(SYMBOL) PSEUDO_END_ERRVAL (SYMBOL)
+
+#if SYSCALL_NOERRNO
+
+/* This kind of system call stub never returns an error.
+ We return the return value register to the caller unexamined. */
+
+T_PSEUDO_NOERRNO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
+ ret_NOERRNO
+T_PSEUDO_END_NOERRNO (SYSCALL_SYMBOL)
+
+#elif SYSCALL_ERRVAL
+
+/* This kind of system call stub returns the errno code as its return
+ value, or zero for success. We may massage the kernel's return value
+ to meet that ABI, but we never set errno here. */
+
+T_PSEUDO_ERRVAL (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
+ ret_ERRVAL
+T_PSEUDO_END_ERRVAL (SYSCALL_SYMBOL)
+
+#else
+
+/* This is a "normal" system call stub: if there is an error,
+ it returns -1 and sets errno. */
+
+T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
+ ret
+T_PSEUDO_END (SYSCALL_SYMBOL)
+
+#endif
+
+syscall_hidden_def (SYSCALL_SYMBOL)