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syscalls.list support for vDSO IFUNCs, use it for x32 gettimeofday and time.
This commit is contained in:
Roland McGrath
parent
d6c33fda03
commit
c14874927b
13
ChangeLog
13
ChangeLog
@ -1,5 +1,18 @@
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2012-05-24 Roland McGrath <roland@hack.frob.com>
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* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list: New file.
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* sysdeps/unix/make-syscalls.sh: Support "syscall:vdso_name@VDSOVER"
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in the third column, to generate for the shared library an IFUNC
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that uses _dl_vdso_vsym.
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* Makerules (COMPILE.c, compile-stdin.c): New variables.
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* Makeconfig (object-suffixes-noshared): New variable.
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* sysdeps/unix/sysv/linux/dl-vdso.h (PREPARE_VERSION_KNOWN): New macro.
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(VDSO_NAME_LINUX_2_6, VDSO_HASH_LINUX_2_6): New macros.
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(VDSO_NAME_LINUX_2_6_15, VDSO_HASH_LINUX_2_6_15): New macros.
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(VDSO_NAME_LINUX_2_6_29, VDSO_HASH_LINUX_2_6_29): New macros.
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[BZ #14132]
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* include/sys/time.h (__gettimeofday): Remove macro.
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(__gettimeofday, gettimeofday): Add libc_hidden_proto.
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@ -720,6 +720,10 @@ CFLAGS-.op = -pg
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libtype.op = lib%_p.a
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endif
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# Convenience variable for when we want to treat shared-library cases
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# differently from the rest.
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object-suffixes-noshared := $(filter-out .os,$(object-suffixes))
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bppfx = BP-
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ifeq (yes,$(build-bounded))
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# Under --enable-bounded, we build the library with `-fbounded-pointers -g'
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@ -366,6 +366,7 @@ compile.c = $(CC) $< -c $(CFLAGS) $(CPPFLAGS)
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compile.cc = $(CXX) $< -c $(CXXFLAGS) $(CPPFLAGS)
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compile.S = $(CC) $< -c $(CPPFLAGS) $(S-CPPFLAGS) \
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$(ASFLAGS) $(ASFLAGS-$(suffix $@))
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COMPILE.c = $(CC) -c $(CFLAGS) $(CPPFLAGS)
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COMPILE.S = $(CC) -c $(CPPFLAGS) $(S-CPPFLAGS) \
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$(ASFLAGS) $(ASFLAGS-$(suffix $@))
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@ -374,6 +375,9 @@ COMPILE.S = $(CC) -c $(CPPFLAGS) $(S-CPPFLAGS) \
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# together. You can't compile the C library with such a compiler.
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OUTPUT_OPTION = -o $@
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# This is the end of the pipeline for compiling generated C code.
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compile-stdin.c = $(COMPILE.c) -o $@ -x c - $(compile-mkdep-flags)
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# We need the $(CFLAGS) to be in there to have the right predefines during
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# the dependency run for C sources. But having it for assembly sources can
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# get the wrong predefines.
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@ -64,10 +64,67 @@ done`
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# Any calls left?
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test -n "$calls" || exit 0
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# This uses variables $weak and $strong.
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emit_weak_aliases()
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{
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# A shortcoming in the current gas is that it will only allow one
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# version-alias per symbol. So we create new strong aliases as needed.
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vcount=""
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for name in $weak; do
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case $name in
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*@@*)
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base=`echo $name | sed 's/@@.*//'`
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ver=`echo $name | sed 's/.*@@//'`
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if test -z "$vcount" ; then
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source=$strong
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vcount=1
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else
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source="${strong}_${vcount}"
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vcount=`expr $vcount + 1`
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echo " echo 'strong_alias ($strong, $source)'; \\"
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fi
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echo " echo 'default_symbol_version($source, $base, $ver)'; \\"
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;;
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*@*)
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base=`echo $name | sed 's/@.*//'`
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ver=`echo $name | sed 's/.*@//'`
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if test -z "$vcount" ; then
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source=$strong
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vcount=1
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else
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source="${strong}_${vcount}"
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vcount=`expr $vcount + 1`
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echo " echo 'strong_alias ($strong, $source)'; \\"
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fi
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echo " echo 'symbol_version ($source, $base, $ver)'; \\"
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;;
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!*)
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name=`echo $name | sed 's/.//'`
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echo " echo 'strong_alias ($strong, $name)'; \\"
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echo " echo 'libc_hidden_def ($name)'; \\"
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;;
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*)
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echo " echo 'weak_alias ($strong, $name)'; \\"
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echo " echo 'libc_hidden_weak ($name)'; \\"
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;;
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esac
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done
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}
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# Emit rules to compile the syscalls remaining in $calls.
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echo "$calls" |
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while read file srcfile caller syscall args strong weak; do
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vdso_syscall=
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case x"$syscall" in
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*:*@*)
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vdso_syscall="${syscall#*:}"
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syscall="${syscall%:*}"
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;;
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esac
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case x"$syscall" in
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x-) callnum=_ ;;
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*)
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@ -144,13 +201,14 @@ while read file srcfile caller syscall args strong weak; do
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# Emit a compilation rule for this syscall.
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if test $shared_only = t; then
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# The versioned symbols are only in the shared library.
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echo "\
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shared-only-routines += $file
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\$(objpfx)${file}.os: \\"
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echo "shared-only-routines += $file"
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test -n "$vdso_syscall" || echo "\$(objpfx)${file}.os: \\"
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else
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object_suffixes='$(object-suffixes)'
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test -z "$vdso_syscall" || object_suffixes='$(object-suffixes-noshared)'
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echo "\
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\$(foreach p,\$(sysd-rules-targets),\
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\$(foreach o,\$(object-suffixes),\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
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\$(foreach o,${object_suffixes},\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
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fi
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echo " \$(..)sysdeps/unix/make-syscalls.sh"
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@ -178,55 +236,43 @@ shared-only-routines += $file
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esac
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# Append any weak aliases or versions defined for this syscall function.
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# A shortcoming in the current gas is that it will only allow one
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# version-alias per symbol. So we create new strong aliases as needed.
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vcount=""
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for name in $weak; do
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case $name in
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*@@*)
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base=`echo $name | sed 's/@@.*//'`
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ver=`echo $name | sed 's/.*@@//'`
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if test -z "$vcount" ; then
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source=$strong
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vcount=1
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else
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source="${strong}_${vcount}"
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vcount=`expr $vcount + 1`
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echo " echo 'strong_alias ($strong, $source)'; \\"
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fi
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echo " echo 'default_symbol_version($source, $base, $ver)'; \\"
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;;
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*@*)
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base=`echo $name | sed 's/@.*//'`
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ver=`echo $name | sed 's/.*@//'`
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if test -z "$vcount" ; then
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source=$strong
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vcount=1
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else
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source="${strong}_${vcount}"
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vcount=`expr $vcount + 1`
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echo " echo 'strong_alias ($strong, $source)'; \\"
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fi
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echo " echo 'symbol_version ($source, $base, $ver)'; \\"
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;;
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!*)
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name=`echo $name | sed 's/.//'`
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echo " echo 'strong_alias ($strong, $name)'; \\"
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echo " echo 'libc_hidden_def ($name)'; \\"
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;;
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*)
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echo " echo 'weak_alias ($strong, $name)'; \\"
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echo " echo 'libc_hidden_weak ($name)'; \\"
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;;
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esac
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done
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emit_weak_aliases
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# And finally, pipe this all into the compiler.
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echo ' ) | $(compile-syscall) '"\
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\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
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if test -n "$vdso_syscall"; then
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# In the shared library, we're going to emit an IFUNC using a vDSO function.
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# $vdso_syscall looks like "name@KERNEL_X.Y" where "name" is the symbol
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# name in the vDSO and KERNEL_X.Y is its symbol version.
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vdso_symbol="${vdso_syscall%@*}"
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vdso_symver="${vdso_syscall#*@}"
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vdso_symver="${vdso_symver//./_}"
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echo "\
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\$(foreach p,\$(sysd-rules-targets),\$(objpfx)\$(patsubst %,\$p,$file).os): \\
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\$(..)sysdeps/unix/make-syscalls.sh\
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\$(make-target-directory)
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(echo '#include <dl-vdso.h>'; \\
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echo 'extern void *${strong}_ifunc (void) __asm (\"${strong}\");'; \\
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echo 'void *'; \\
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echo '${strong}_ifunc (void)'; \\
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echo '{'; \\
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echo ' PREPARE_VERSION_KNOWN (symver, ${vdso_symver});'; \\
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echo ' return _dl_vdso_vsym (\"${vdso_symbol}\", &symver);'; \\
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echo '}'; \\
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echo 'asm (\".type ${strong}, %gnu_indirect_function\");'; \\"
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# This is doing "libc_hidden_def (${strong})", but the compiler
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# doesn't know that we've defined ${strong} in the same file, so
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# we can't do it the normal way.
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echo "\
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echo 'asm (\".globl __GI_${strong}\\n\"'; \\
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echo ' \"__GI_${strong} = ${strong}\");'; \\"
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emit_weak_aliases
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echo ' ) | $(compile-stdin.c) '"\
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\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
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fi
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if test $shared_only = t; then
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# The versioned symbols are only in the shared library.
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echo endif
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@ -33,6 +33,17 @@
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/* We don't have a specific file where the symbol can be found. */ \
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var.filename = NULL
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/* Use this for the known version sets defined below, where we
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record their precomputed hash values only once, in this file. */
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#define PREPARE_VERSION_KNOWN(var, vname) \
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PREPARE_VERSION (var, VDSO_NAME_##vname, VDSO_HASH_##vname)
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#define VDSO_NAME_LINUX_2_6 "LINUX_2.6"
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#define VDSO_HASH_LINUX_2_6 61765110
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#define VDSO_NAME_LINUX_2_6_15 "LINUX_2.6.15"
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#define VDSO_HASH_LINUX_2_6_15 123718565
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#define VDSO_NAME_LINUX_2_6_29 "LINUX_2.6.29"
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#define VDSO_HASH_LINUX_2_6_29 123718585
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/* Functions for resolving symbols in the VDSO link map. */
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extern void *_dl_vdso_vsym (const char *name,
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@ -1,6 +1,8 @@
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# File name Caller Syscall name # args Strong name Weak names
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fallocate - fallocate Ci:iiii fallocate fallocate64
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gettimeofday - gettimeofday:__vdso_gettimeofday@LINUX_2.6 i:pP __gettimeofday gettimeofday
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posix_fadvise - fadvise64 Vi:iiii posix_fadvise posix_fadvise64
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preadv - preadv Ci:ipii preadv preadv64
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pwritev - pwritev Ci:ipii pwritev pwritev64
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time - time:__vdso_time@LINUX_2.6 Ei:P time
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