mirror of
https://sourceware.org/git/glibc.git
synced 2024-09-19 16:10:01 +00:00
128 lines
4.8 KiB
ArmAsm
128 lines
4.8 KiB
ArmAsm
/* Assembly code template for system call stubs.
|
|
Copyright (C) 2009-2024 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
|
|
<https://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. Cancellable syscalls
|
|
should be implemented using C implementation with SYSCALL_CANCEL macro.
|
|
|
|
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_ULONG_ARG_1 the first unsigned long int argument this
|
|
call takes. 0 means that there are no
|
|
unsigned long int arguments.
|
|
SYSCALL_ULONG_ARG_2 the second unsigned long int argument this
|
|
call takes. 0 means that there is at most
|
|
one unsigned long int argument.
|
|
SYSCALL_SYMBOL primary symbol name
|
|
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. */
|
|
|
|
#include <sysdep.h>
|
|
|
|
/* This indirection is needed so that SYMBOL gets macro-expanded. */
|
|
#define syscall_hidden_def(SYMBOL) hidden_def (SYMBOL)
|
|
|
|
/* If PSEUDOS_HAVE_ULONG_INDICES is defined, PSEUDO and T_PSEUDO macros
|
|
have 2 extra arguments for unsigned long int arguments:
|
|
Extra argument 1: Position of the first unsigned long int argument.
|
|
Extra argument 2: Position of the second unsigned long int argument.
|
|
*/
|
|
#ifndef PSEUDOS_HAVE_ULONG_INDICES
|
|
# undef SYSCALL_ULONG_ARG_1
|
|
# define SYSCALL_ULONG_ARG_1 0
|
|
#endif
|
|
|
|
#if SYSCALL_ULONG_ARG_1
|
|
# define T_PSEUDO(SYMBOL, NAME, N, U1, U2) \
|
|
PSEUDO (SYMBOL, NAME, N, U1, U2)
|
|
# define T_PSEUDO_NOERRNO(SYMBOL, NAME, N, U1, U2) \
|
|
PSEUDO_NOERRNO (SYMBOL, NAME, N, U1, U2)
|
|
# define T_PSEUDO_ERRVAL(SYMBOL, NAME, N, U1, U2) \
|
|
PSEUDO_ERRVAL (SYMBOL, NAME, N, U1, U2)
|
|
#else
|
|
# 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)
|
|
#endif
|
|
#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. */
|
|
|
|
# if SYSCALL_ULONG_ARG_1
|
|
T_PSEUDO_NOERRNO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS,
|
|
SYSCALL_ULONG_ARG_1, SYSCALL_ULONG_ARG_2)
|
|
# else
|
|
T_PSEUDO_NOERRNO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
|
|
# endif
|
|
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. */
|
|
|
|
# if SYSCALL_ULONG_ARG_1
|
|
T_PSEUDO_ERRVAL (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS,
|
|
SYSCALL_ULONG_ARG_1, SYSCALL_ULONG_ARG_2)
|
|
# else
|
|
T_PSEUDO_ERRVAL (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
|
|
# endif
|
|
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. */
|
|
|
|
# if SYSCALL_ULONG_ARG_1
|
|
T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS,
|
|
SYSCALL_ULONG_ARG_1, SYSCALL_ULONG_ARG_2)
|
|
# else
|
|
T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
|
|
# endif
|
|
ret
|
|
T_PSEUDO_END (SYSCALL_SYMBOL)
|
|
|
|
#endif
|
|
|
|
syscall_hidden_def (SYSCALL_SYMBOL)
|