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Remove vDSO support from make-syscall.sh

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The auto-generated vDSO call shows some issues:

  - It requires sync the auto-generated C file with current glibc
    implementation;
  - It still uses symbol redirections hacks where libc-symbols.h
    provide macros that uses compiler builtins
    (libc_ifunc_redirected for instance);
  - It does not handle all required compiler handling
    (inhibit_stack_protector on iFUNC resolver).
  - No architecure uses it.

Checked with a build against all major ABIs.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This commit is contained in:
Adhemerval Zanella 2019-11-29 16:28:46 -03:00
parent bc36727be9
commit 2822aaf4f7
1 changed files with 1 additions and 44 deletions
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45
sysdeps/unix/make-syscalls.sh
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@ -149,14 +149,6 @@ emit_weak_aliases()
echo "$calls" |
while read file srcfile caller syscall args strong weak; do
vdso_syscall=
case x"$syscall" in
*:*@*)
vdso_syscall="${syscall#*:}"
syscall="${syscall%:*}"
;;
esac
case x"$syscall" in
x-) callnum=_ ;;
*)
@ -233,10 +225,9 @@ while read file srcfile caller syscall args strong weak; do
if test $shared_only = t; then
# The versioned symbols are only in the shared library.
echo "shared-only-routines += $file"
test -n "$vdso_syscall" || echo "\$(objpfx)${file}.os: \\"
echo "\$(objpfx)${file}.os: \\"
else
object_suffixes='$(object-suffixes)'
test -z "$vdso_syscall" || object_suffixes='$(object-suffixes-noshared)'
echo "\
\$(foreach p,\$(sysd-rules-targets),\
\$(foreach o,${object_suffixes},\$(objpfx)\$(patsubst %,\$p,$file)\$o)): \\"
@ -268,40 +259,6 @@ while read file srcfile caller syscall args strong weak; do
echo ' ) | $(compile-syscall) '"\
\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))"
if test -n "$vdso_syscall"; then
# In the shared library, we're going to emit an IFUNC using a vDSO function.
# $vdso_syscall looks like "name@KERNEL_X.Y" where "name" is the symbol
# name in the vDSO and KERNEL_X.Y is its symbol version.
vdso_symbol="${vdso_syscall%@*}"
vdso_symver="${vdso_syscall#*@}"
vdso_symver=`echo "$vdso_symver" | sed 's/\./_/g'`
cat <<EOF
\$(foreach p,\$(sysd-rules-targets),\$(objpfx)\$(patsubst %,\$p,$file).os): \\
\$(..)sysdeps/unix/make-syscalls.sh
\$(make-target-directory)
(echo '#define ${strong} __redirect_${strong}'; \\
echo '#include <dl-vdso.h>'; \\
echo '#undef ${strong}'; \\
echo '#define vdso_ifunc_init()'; \\
echo '__ifunc (__redirect_${strong}, ${strong},'; \\
echo ' get_vdso_symbol ("${vdso_symbol}"), void,'; \\
echo ' vdso_ifunc_init)'; \\
EOF
# This is doing "hidden_def (${strong})", but the compiler
# doesn't know that we've defined ${strong} in the same file, so
# we can't do it the normal way.
cat <<EOF
echo 'asm (".globl __GI_${strong}");'; \\
echo 'asm ("__GI_${strong} = ${strong}");'; \\
EOF
emit_weak_aliases
cat <<EOF
) | \$(compile-stdin.c) \
\$(foreach p,\$(patsubst %$file,%,\$(basename \$(@F))),\$(\$(p)CPPFLAGS))
EOF
fi
if test $shared_only = t; then
# The versioned symbols are only in the shared library.
echo endif