From 2822aaf4f7426289a7e29086a4ee430f683e4b55 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Fri, 29 Nov 2019 16:28:46 -0300
Subject: Remove vDSO support from make-syscall.sh

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>
---
 sysdeps/unix/make-syscalls.sh | 45 +------------------------------------------
 1 file changed, 1 insertion(+), 44 deletions(-)

diff --git a/sysdeps/unix/make-syscalls.sh b/sysdeps/unix/make-syscalls.sh
index fe24bbc78f..c07626677f 100644
--- a/sysdeps/unix/make-syscalls.sh
+++ b/sysdeps/unix/make-syscalls.sh
@@ -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
-- 
cgit 1.4.1