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Add sysdeps/unix/syscall-template.S; build syscall stubs with deps an…
…d -g pointing to it.
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Roland McGrath committed Aug 24, 2009
1 parent 7b943af commit 036e46b
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Showing 4 changed files with 124 additions and 24 deletions.
9 changes: 9 additions & 0 deletions ChangeLog
@@ -1,3 +1,12 @@
2009-08-24 Roland McGrath <roland@redhat.com>

* sysdeps/unix/syscall-template.S: New file.
* sysdeps/unix/make-syscalls.sh: Generate rules to use it.
* sysdeps/unix/Makefile (omit-deps): Do not omit syscall stubs' deps.
(compile-syscall): Pass mkdep and -g options as normal.
(s-proto.d, s-proto-cancel.d): Don't "-include" these.
(common-generated): Don't add them here.

2009-08-24 Ulrich Drepper <drepper@redhat.com>

* math/math.h: Define math_errhandling of __FAST_MATH__ is not defined.
Expand Down
18 changes: 7 additions & 11 deletions sysdeps/unix/Makefile
@@ -1,4 +1,4 @@
# Copyright (C) 1991,1992,1993,1994,1995,1996,1997,1998,1999,2003, 2006, 2008
# Copyright (C) 1991,1992,1993,1994,1995,1996,1997,1998,1999,2003,2006,2008,2009
# Free Software Foundation, Inc.
# This file is part of the GNU C Library.

Expand Down Expand Up @@ -260,7 +260,6 @@ ifndef inhibit-unix-syscalls
# which specifies objects to be compiled as simple Unix system calls.

-include $(common-objpfx)sysd-syscalls
omit-deps += $(foreach t,$(sysd-rules-targets),$(unix-syscalls:%=$t))

ifeq (misc,$(subdir))
sysdep_routines += $(unix-extra-syscalls)
Expand Down Expand Up @@ -306,9 +305,9 @@ endif
endif

# This is the end of the pipeline for compiling the syscall stubs.
# The stdin in assembler with cpp using sysdep.h macros.
# Be sure to disable debugging info since it would all just say "<stdin>".
compile-syscall = $(filter-out -g%,$(COMPILE.S)) -x assembler-with-cpp -o $@ -
# The stdin is assembler with cpp using sysdep.h macros.
compile-syscall = $(COMPILE.S) -o $@ -x assembler-with-cpp - \
$(compile-mkdep-flags)

ifndef avoid-generated
$(common-objpfx)sysd-syscalls: $(..)sysdeps/unix/make-syscalls.sh \
Expand All @@ -323,24 +322,21 @@ $(common-objpfx)sysd-syscalls: $(..)sysdeps/unix/make-syscalls.sh \
mv -f $@T $@
endif

# The syscall objects depend on s-proto.d or s-proto-cancel.d, which
# are generated to specify dependencies generated syscalls have on
# headers.
# The $(bppfx)syscall.ob objects depend on s-proto-bp.d, which are
# generated to specify dependencies generated BP stubs have on headers.
# These deps use file names relative to a subdir, so don't
# include them in the parent directory.
ifneq (,$(filter $(unix-syscalls),$(routines) $(sysdep_routines) $(aux)))
ifndef no_deps
-include $(common-objpfx)s-proto.d
-include $(common-objpfx)s-proto-bp.d
-include $(common-objpfx)s-proto-cancel.d
endif
endif

$(common-objpfx)s-%.d: $(..)sysdeps/unix/s-%.S \
$(wildcard $(+sysdep_dirs:%=%/syscalls.list))
$(+make-deps)

common-generated += s-proto.d s-proto-bp.d s-proto-cancel.d
common-generated += s-proto-bp.d
postclean-generated += sysd-syscalls

endif
33 changes: 20 additions & 13 deletions sysdeps/unix/make-syscalls.sh
Expand Up @@ -83,12 +83,13 @@ while read file srcfile caller syscall args strong weak; do
;;
esac
cancellable=
noerrno=
cancellable=0
noerrno=0
errval=0
case $args in
C*) cancellable=-cancel; args=`echo $args | sed 's/C:\?//'`;;
E*) noerrno=_NOERRNO; args=`echo $args | sed 's/E:\?//'`;;
V*) noerrno=_ERRVAL; args=`echo $args | sed 's/V:\?//'`;;
C*) cancellable=1; args=`echo $args | sed 's/C:\?//'`;;
E*) noerrno=1; args=`echo $args | sed 's/E:\?//'`;;
V*) errval=1; args=`echo $args | sed 's/V:\?//'`;;
esac
# Derive the number of arguments from the argument signature
Expand All @@ -115,7 +116,7 @@ while read file srcfile caller syscall args strong weak; do
x--)
# Undefined callnum for an extra syscall.
if [ x$caller != x- ]; then
if [ x$noerrno != x ]; then
if [ $noerrno != 0 ]; then
echo >&2 "$0: no number for $fileno, no-error syscall ($strong $weak)"
exit 2
fi
Expand Down Expand Up @@ -151,7 +152,7 @@ shared-only-routines += $file
;;
esac
echo " \$(common-objpfx)s-proto$cancellable.d"
echo " \$(..)sysdeps/unix/make-syscalls.sh"
case x"$callnum" in
x_)
echo "\
Expand All @@ -161,11 +162,17 @@ shared-only-routines += $file
x*)
echo "\
\$(make-target-directory)
(echo '#include <sysdep$cancellable.h>'; \\
echo 'PSEUDO$noerrno ($strong, $syscall, $nargs)'; \\
echo ' ret$noerrno'; \\
echo 'PSEUDO_END$noerrno($strong)'; \\
echo 'libc_hidden_def ($strong)'; \\"
(echo '#define SYSCALL_NAME $syscall'; \\
echo '#define SYSCALL_NARGS $nargs'; \\
echo '#define SYSCALL_SYMBOL $strong'; \\"
[ $cancellable = 0 ] || echo "\
echo '#define SYSCALL_CANCELLABLE 1'; \\"
[ $noerrno = 0 ] || echo "\
echo '#define SYSCALL_NOERRNO 1'; \\"
[ $errval = 0 ] || echo "\
echo '#define SYSCALL_ERRVAL 1'; \\"
echo "\
echo '#include <syscall-template.S>'; \\"
;;
esac
Expand Down Expand Up @@ -201,7 +208,7 @@ shared-only-routines += $file
vcount=`expr $vcount + 1`
echo " echo 'strong_alias ($strong, $source)'; \\"
fi
echo " echo 'symbol_version($source, $base, $ver)'; \\"
echo " echo 'symbol_version ($source, $base, $ver)'; \\"
;;
!*)
name=`echo $name | sed 's/.//'`
Expand Down
88 changes: 88 additions & 0 deletions sysdeps/unix/syscall-template.S
@@ -0,0 +1,88 @@
/* Assembly code template for system call stubs.
Copyright (C) 2009 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */

/* 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

#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

libc_hidden_def (SYSCALL_SYMBOL)

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