Reduce the statically linked startup code [BZ #23323]

It turns out the startup code in csu/elf-init.c has a perfect pair of
ROP gadgets (see Marco-Gisbert and Ripoll-Ripoll, "return-to-csu: A
New Method to Bypass 64-bit Linux ASLR").  These functions are not
needed in dynamically-linked binaries because DT_INIT/DT_INIT_ARRAY
are already processed by the dynamic linker.  However, the dynamic
linker skipped the main program for some reason.  For maximum
backwards compatibility, this is not changed, and instead, the main
map is consulted from __libc_start_main if the init function argument
is a NULL pointer.

For statically linked binaries, the old approach based on linker
symbols is still used because there is nothing else available.

A new symbol version __libc_start_main@@GLIBC_2.34 is introduced because
new binaries running on an old libc would not run their ELF
constructors, leading to difficult-to-debug issues.

63 files changed, 276 insertions, 315 deletions

diff --git a/csu/Makefile b/csu/Makefile
index c9385df2e9..e587434be8 100644
--- a/csu/Makefile
+++ b/csu/Makefile
@@ -27,10 +27,9 @@ subdir := csu
 include ../Makeconfig
 
 routines = init-first libc-start $(libc-init) sysdep version check_fds \
-	   libc-tls elf-init dso_handle
+	   libc-tls dso_handle
 aux	 = errno
 elide-routines.os = libc-tls
-static-only-routines = elf-init
 csu-dummies = $(filter-out $(start-installed-name),crt1.o Mcrt1.o)
 extra-objs = start.o \
 	     $(start-installed-name) g$(start-installed-name) $(csu-dummies) \
@@ -59,13 +58,6 @@ CFLAGS-.os += $(no-stack-protector)
 # but it does not matter for this source file.
 CFLAGS-static-reloc.os += $(stack-protector)
 
-# This file is not actually part of the startup code in the nonshared
-# case and statically linked into applications.  See
-# <https://sourceware.org/bugzilla/show_bug.cgi?id=23323>,
-# <https://sourceware.org/ml/libc-alpha/2018-06/msg00717.html>.
-# Also see the note above regarding STACK_PROTECTOR_LEVEL.
-CFLAGS-elf-init.oS += $(stack-protector)
-
 ifeq (yes,$(build-shared))
 extra-objs += S$(start-installed-name) gmon-start.os
 ifneq ($(start-installed-name),$(static-start-installed-name))
diff --git a/csu/Versions b/csu/Versions
index 43010c3443..8e1b21948e 100644
--- a/csu/Versions
+++ b/csu/Versions
@@ -7,6 +7,9 @@ libc {
     # New special glibc functions.
     gnu_get_libc_release; gnu_get_libc_version;
   }
+  GLIBC_2.34 {
+    __libc_start_main;
+  }
   GLIBC_PRIVATE {
     errno;
   }
diff --git a/csu/elf-init.c b/csu/elf-init.c
deleted file mode 100644
index 6e96ab7fce..0000000000
--- a/csu/elf-init.c
+++ /dev/null
@@ -1,107 +0,0 @@
-/* Startup support for ELF initializers/finalizers in the main executable.
-   Copyright (C) 2002-2021 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.
-
-   In addition to the permissions in the GNU Lesser General Public
-   License, the Free Software Foundation gives you unlimited
-   permission to link the compiled version of this file with other
-   programs, and to distribute those programs without any restriction
-   coming from the use of this file. (The GNU Lesser General Public
-   License restrictions do apply in other respects; for example, they
-   cover modification of the file, and distribution when not linked
-   into another program.)
-
-   Note that people who make modified versions of this file are not
-   obligated to grant this special exception for their modified
-   versions; it is their choice whether to do so. The GNU Lesser
-   General Public License gives permission to release a modified
-   version without this exception; this exception also makes it
-   possible to release a modified version which carries forward this
-   exception.
-
-   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/>.  */
-
-#include <stddef.h>
-#include <elf-initfini.h>
-
-
-/* These magic symbols are provided by the linker.  */
-extern void (*__preinit_array_start []) (int, char **, char **)
-  attribute_hidden;
-extern void (*__preinit_array_end []) (int, char **, char **)
-  attribute_hidden;
-extern void (*__init_array_start []) (int, char **, char **)
-  attribute_hidden;
-extern void (*__init_array_end []) (int, char **, char **)
-  attribute_hidden;
-extern void (*__fini_array_start []) (void) attribute_hidden;
-extern void (*__fini_array_end []) (void) attribute_hidden;
-
-
-#if ELF_INITFINI
-/* These function symbols are provided for the .init/.fini section entry
-   points automagically by the linker.  */
-extern void _init (void);
-extern void _fini (void);
-#endif
-
-
-/* These functions are passed to __libc_start_main by the startup code.
-   These get statically linked into each program.  For dynamically linked
-   programs, this module will come from libc_nonshared.a and differs from
-   the libc.a module in that it doesn't call the preinit array.  */
-
-
-void
-__libc_csu_init (int argc, char **argv, char **envp)
-{
-  /* For dynamically linked executables the preinit array is executed by
-     the dynamic linker (before initializing any shared object).  */
-
-#ifndef LIBC_NONSHARED
-  /* For static executables, preinit happens right before init.  */
-  {
-    const size_t size = __preinit_array_end - __preinit_array_start;
-    size_t i;
-    for (i = 0; i < size; i++)
-      (*__preinit_array_start [i]) (argc, argv, envp);
-  }
-#endif
-
-#if ELF_INITFINI
-  _init ();
-#endif
-
-  const size_t size = __init_array_end - __init_array_start;
-  for (size_t i = 0; i < size; i++)
-      (*__init_array_start [i]) (argc, argv, envp);
-}
-
-/* This function should not be used anymore.  We run the executable's
-   destructor now just like any other.  We cannot remove the function,
-   though.  */
-void
-__libc_csu_fini (void)
-{
-#ifndef LIBC_NONSHARED
-  size_t i = __fini_array_end - __fini_array_start;
-  while (i-- > 0)
-    (*__fini_array_start [i]) ();
-
-# if ELF_INITFINI
-  _fini ();
-# endif
-#endif
-}
diff --git a/csu/libc-start.c b/csu/libc-start.c
index feb0d7ce11..05ff7afddf 100644
--- a/csu/libc-start.c
+++ b/csu/libc-start.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 1998-2021 Free Software Foundation, Inc.
+/* Perform initialization and invoke main.
+   Copyright (C) 1998-2021 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
@@ -15,10 +16,15 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+/* Note: This code is only part of the startup code proper for
+   statically linked binaries.  For dynamically linked binaries, it
+   resides in libc.so.  */
+
 /* Mark symbols hidden in static PIE for early self relocation to work.  */
 #if BUILD_PIE_DEFAULT
 # pragma GCC visibility push(hidden)
 #endif
+
 #include <assert.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -29,6 +35,8 @@
 #include <libc-internal.h>
 #include <elf/libc-early-init.h>
 #include <stdbool.h>
+#include <elf-initfini.h>
+#include <shlib-compat.h>
 
 #include <elf/dl-tunables.h>
 
@@ -95,9 +103,11 @@ apply_irel (void)
 # else
 #  define STATIC static inline __attribute__ ((always_inline))
 # endif
+# define DO_DEFINE_LIBC_START_MAIN_VERSION 0
 #else
 # define STATIC
-# define LIBC_START_MAIN __libc_start_main
+# define LIBC_START_MAIN __libc_start_main_impl
+# define DO_DEFINE_LIBC_START_MAIN_VERSION 1
 #endif
 
 #ifdef MAIN_AUXVEC_ARG
@@ -113,6 +123,92 @@ apply_irel (void)
 # define ARCH_INIT_CPU_FEATURES()
 #endif
 
+#ifdef SHARED
+/* Initialization for dynamic executables.  Find the main executable
+   link map and run its init functions.  */
+static void
+call_init (int argc, char **argv, char **env)
+{
+  /* Obtain the main map of the executable.  */
+  struct link_map *l = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
+
+  /* DT_PREINIT_ARRAY is not processed here.  It is already handled in
+     _dl_init in elf/dl-init.c.  Also see the call_init function in
+     the same file.  */
+
+  if (ELF_INITFINI && l->l_info[DT_INIT] != NULL)
+    DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr,
+		    argc, argv, env);
+
+  ElfW(Dyn) *init_array = l->l_info[DT_INIT_ARRAY];
+  if (init_array != NULL)
+    {
+      unsigned int jm
+	= l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
+      ElfW(Addr) *addrs = (void *) (init_array->d_un.d_ptr + l->l_addr);
+      for (unsigned int j = 0; j < jm; ++j)
+	((dl_init_t) addrs[j]) (argc, argv, env);
+    }
+}
+
+#else /* !SHARED */
+
+/* These magic symbols are provided by the linker.  */
+extern void (*__preinit_array_start []) (int, char **, char **)
+  attribute_hidden;
+extern void (*__preinit_array_end []) (int, char **, char **)
+  attribute_hidden;
+extern void (*__init_array_start []) (int, char **, char **)
+  attribute_hidden;
+extern void (*__init_array_end []) (int, char **, char **)
+  attribute_hidden;
+extern void (*__fini_array_start []) (void) attribute_hidden;
+extern void (*__fini_array_end []) (void) attribute_hidden;
+
+# if ELF_INITFINI
+/* These function symbols are provided for the .init/.fini section entry
+   points automagically by the linker.  */
+extern void _init (void);
+extern void _fini (void);
+# endif
+
+/* Initialization for static executables.  There is no dynamic
+   segment, so we access the symbols directly.  */
+static void
+call_init (int argc, char **argv, char **envp)
+{
+  /* For static executables, preinit happens right before init.  */
+  {
+    const size_t size = __preinit_array_end - __preinit_array_start;
+    size_t i;
+    for (i = 0; i < size; i++)
+      (*__preinit_array_start [i]) (argc, argv, envp);
+  }
+
+# if ELF_INITFINI
+  _init ();
+# endif
+
+  const size_t size = __init_array_end - __init_array_start;
+  for (size_t i = 0; i < size; i++)
+      (*__init_array_start [i]) (argc, argv, envp);
+}
+
+/* Likewise for the destructor.  */
+static void
+call_fini (void *unused)
+{
+  size_t i = __fini_array_end - __fini_array_start;
+  while (i-- > 0)
+    (*__fini_array_start [i]) ();
+
+# if ELF_INITFINI
+  _fini ();
+# endif
+}
+
+#endif /* !SHARED */
+
 #include <libc-start.h>
 
 STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
@@ -129,9 +225,16 @@ STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
      __attribute__ ((noreturn));
 
 
-/* Note: the fini parameter is ignored here for shared library.  It
-   is registered with __cxa_atexit.  This had the disadvantage that
-   finalizers were called in more than one place.  */
+/* Note: The init and fini parameters are no longer used.  fini is
+   completely unused, init is still called if not NULL, but the
+   current startup code always passes NULL.  (In the future, it would
+   be possible to use fini to pass a version code if init is NULL, to
+   indicate the link-time glibc without introducing a hard
+   incompatibility for new programs with older glibc versions.)
+
+   For dynamically linked executables, the dynamic segment is used to
+   locate constructors and destructors.  For statically linked
+   executables, the relevant symbols are access directly.  */
 STATIC int
 LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
 		 int argc, char **argv,
@@ -258,9 +361,8 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
      run the constructors in `_dl_start_user'.  */
   __libc_init_first (argc, argv, __environ);
 
-  /* Register the destructor of the program, if any.  */
-  if (fini)
-    __cxa_atexit ((void (*) (void *)) fini, NULL, NULL);
+  /* Register the destructor of the statically-linked program.  */
+  __cxa_atexit (call_fini, NULL, NULL);
 
   /* Some security at this point.  Prevent starting a SUID binary where
      the standard file descriptors are not opened.  We have to do this
@@ -268,15 +370,24 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
      loader did the work already.  */
   if (__builtin_expect (__libc_enable_secure, 0))
     __libc_check_standard_fds ();
-#endif
+#endif /* !SHARED */
 
   /* Call the initializer of the program, if any.  */
 #ifdef SHARED
   if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
     GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]);
-#endif
-  if (init)
+
+  if (init != NULL)
+    /* This is a legacy program which supplied its own init
+       routine.  */
     (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
+  else
+    /* This is a current program.  Use the dynamic segment to find
+       constructors.  */
+    call_init (argc, argv, __environ);
+#else /* !SHARED */
+  call_init (argc, argv, __environ);
+#endif /* SHARED */
 
 #ifdef SHARED
   /* Auditing checkpoint: we have a new object.  */
@@ -365,3 +476,36 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
 
   exit (result);
 }
+
+/* Starting with glibc 2.34, the init parameter is always NULL.  Older
+   libcs are not prepared to handle that.  The macro
+   DEFINE_LIBC_START_MAIN_VERSION creates GLIBC_2.34 alias, so that
+   newly linked binaries reflect that dependency.  The macros below
+   expect that the exported function is called
+   __libc_start_main_impl.  */
+#ifdef SHARED
+# define DEFINE_LIBC_START_MAIN_VERSION \
+  DEFINE_LIBC_START_MAIN_VERSION_1 \
+  strong_alias (__libc_start_main_impl, __libc_start_main_alias_2)	\
+  versioned_symbol (libc, __libc_start_main_alias_2, __libc_start_main, \
+		    GLIBC_2_34);
+
+# if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_34)
+#  define DEFINE_LIBC_START_MAIN_VERSION_1 \
+  strong_alias (__libc_start_main_impl, __libc_start_main_alias_1)	\
+  compat_symbol (libc, __libc_start_main_alias_1, __libc_start_main, GLIBC_2_0);
+#  else
+#  define DEFINE_LIBC_START_MAIN_VERSION_1
+# endif
+#else  /* !SHARED */
+/* Enable calling the function under its exported name.  */
+# define DEFINE_LIBC_START_MAIN_VERSION \
+  strong_alias (__libc_start_main_impl, __libc_start_main)
+#endif
+
+/* Only define the version information if LIBC_START_MAIN was not set.
+   If there is a wrapper file, it must expand
+   DEFINE_LIBC_START_MAIN_VERSION on its own.  */
+#if DO_DEFINE_LIBC_START_MAIN_VERSION
+DEFINE_LIBC_START_MAIN_VERSION
+#endif
diff --git a/elf/dl-init.c b/elf/dl-init.c
index b7e4b8a3af..f924d26642 100644
--- a/elf/dl-init.c
+++ b/elf/dl-init.c
@@ -22,10 +22,6 @@
 #include <elf-initfini.h>
 
 
-/* Type of the initializer.  */
-typedef void (*init_t) (int, char **, char **);
-
-
 static void
 call_init (struct link_map *l, int argc, char **argv, char **env)
 {
@@ -71,7 +67,7 @@ call_init (struct link_map *l, int argc, char **argv, char **env)
 
       addrs = (ElfW(Addr) *) (init_array->d_un.d_ptr + l->l_addr);
       for (j = 0; j < jm; ++j)
-	((init_t) addrs[j]) (argc, argv, env);
+	((dl_init_t) addrs[j]) (argc, argv, env);
     }
 }
 
@@ -103,7 +99,7 @@ _dl_init (struct link_map *main_map, int argc, char **argv, char **env)
 
       addrs = (ElfW(Addr) *) (preinit_array->d_un.d_ptr + main_map->l_addr);
       for (cnt = 0; cnt < i; ++cnt)
-	((init_t) addrs[cnt]) (argc, argv, env);
+	((dl_init_t) addrs[cnt]) (argc, argv, env);
     }
 
   /* Stupid users forced the ELF specification to be changed.  It now
diff --git a/sysdeps/aarch64/start.S b/sysdeps/aarch64/start.S
index 3761cbd7ee..417da8802b 100644
--- a/sysdeps/aarch64/start.S
+++ b/sysdeps/aarch64/start.S
@@ -63,26 +63,16 @@ ENTRY(_start)
 # ifdef SHARED
         adrp    x0, :got:main
 	ldr     PTR_REG (0), [x0, #:got_lo12:main]
-
-        adrp    x3, :got:__libc_csu_init
-	ldr     PTR_REG (3), [x3, #:got_lo12:__libc_csu_init]
-
-        adrp    x4, :got:__libc_csu_fini
-	ldr     PTR_REG (4), [x4, #:got_lo12:__libc_csu_fini]
 # else
 	adrp	x0, __wrap_main
 	add	x0, x0, :lo12:__wrap_main
-	adrp	x3, __libc_csu_init
-	add	x3, x3, :lo12:__libc_csu_init
-	adrp	x4, __libc_csu_fini
-	add	x4, x4, :lo12:__libc_csu_fini
 # endif
 #else
 	/* Set up the other arguments in registers */
 	MOVL (0, main)
-	MOVL (3, __libc_csu_init)
-	MOVL (4, __libc_csu_fini)
 #endif
+	mov	x3, #0		/* Used to be init.  */
+	mov	x4, #0		/* Used to be fini.  */
 
 	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini,
 			      stack_end) */
diff --git a/sysdeps/alpha/start.S b/sysdeps/alpha/start.S
index f3eb2029e1..65dcd4d392 100644
--- a/sysdeps/alpha/start.S
+++ b/sysdeps/alpha/start.S
@@ -55,9 +55,8 @@ _start:
 	ldl	a1, 16(sp)	/* get argc */
 	lda	a2, 24(sp)	/* get argv */
 
-  /* Load address of our own entry points to .fini and .init.  */
-	lda	a3, __libc_csu_init
-	lda	a4, __libc_csu_fini
+	mov	$r31, a3 	/* Used to be init.  */
+	mov	$r31, a4 	/* Used to be fini.  */
 
   /* Store address of the shared library termination function.  */
 	mov	v0, a5
diff --git a/sysdeps/arc/start.S b/sysdeps/arc/start.S
index dbec87e6bb..5302a57cab 100644
--- a/sysdeps/arc/start.S
+++ b/sysdeps/arc/start.S
@@ -49,15 +49,14 @@ ENTRY (ENTRY_POINT)
 
 	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end).  */
 
+	mov_s	r3, 0 		/* Used to be init.  */
+	mov	r4, 0		/* Used to be fini.  */
+
 #ifdef SHARED
 	ld	r0, [pcl, @main@gotpc]
-	ld	r3, [pcl, @__libc_csu_init@gotpc]
-	ld	r4, [pcl, @__libc_csu_fini@gotpc]
 	bl	__libc_start_main@plt
 #else
 	mov_s	r0, main
-	mov_s	r3, __libc_csu_init
-	mov	r4, __libc_csu_fini
 	bl	__libc_start_main
 #endif
 
diff --git a/sysdeps/arm/start.S b/sysdeps/arm/start.S
index 30f69e1b07..9b56bc0cca 100644
--- a/sysdeps/arm/start.S
+++ b/sysdeps/arm/start.S
@@ -94,30 +94,20 @@ _start:
 	adr a4, .L_GOT
 	add sl, sl, a4
 
-	ldr ip, .L_GOT+4	/* __libc_csu_fini */
-	ldr ip, [sl, ip]
+	mov a4, #0		/* Used to be init.  */
+	push { a4 }		/* Used to be fini.  */
 
-	push { ip }		/* Push __libc_csu_fini */
-
-	ldr a4, .L_GOT+8	/* __libc_csu_init */
-	ldr a4, [sl, a4]
-
-	ldr a1, .L_GOT+12	/* main */
+	ldr a1, .L_GOT+4	/* main */
 	ldr a1, [sl, a1]
 
 	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
 	/* Let the libc call main and exit with its return code.  */
 	bl __libc_start_main(PLT)
 #else
-	/* Fetch address of __libc_csu_fini */
-	ldr ip, =__libc_csu_fini
-
-	/* Push __libc_csu_fini */
-	push { ip }
 
-	/* Set up the other arguments in registers */
+	mov a4, #0		/* Used to init.  */
+	push { a4 }		/* Used to fini.  */
 	ldr a1, =main
-	ldr a4, =__libc_csu_init
 
 	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end) */
 	/* Let the libc call main and exit with its return code.  */
@@ -131,8 +121,6 @@ _start:
 	.align 2
 .L_GOT:
 	.word _GLOBAL_OFFSET_TABLE_ - .L_GOT
-	.word __libc_csu_fini(GOT)
-	.word __libc_csu_init(GOT)
 	.word main(GOT)
 #endif
 
diff --git a/sysdeps/csky/abiv2/start.S b/sysdeps/csky/abiv2/start.S
index d65e37e61b..a565cfa87b 100644
--- a/sysdeps/csky/abiv2/start.S
+++ b/sysdeps/csky/abiv2/start.S
@@ -66,13 +66,9 @@ _start:
 .Lgetpc:
 	lrw	gb, .Lgetpc@GOTPC
 	addu	gb, t0
-	lrw	a3, __libc_csu_fini@GOT
-	ldr.w	a3, (gb, a3 << 0)
-	stw	a3, (sp, 0)
 
-	lrw	a3, __libc_csu_init@GOT
-	addu	a3, gb
-	ldw	a3, (a3, 0)
+	movi	a3, 0		/* Used to be init.  */
+	stw 	a3, (sp, 0) 	/* Used to be fini.  */
 
 	lrw	t0, main@GOT
 	addu	t0, gb
@@ -85,14 +81,9 @@ _start:
 	ldr.w	t1, (gb, t1 << 0)
 	jsr	t1
 #else
-	/* Fetch address of __libc_csu_fini.  */
-	lrw	a0, __libc_csu_fini
-	/* Push __libc_csu_fini */
-	stw	a0, (sp, 0)
-
-	/* Set up the other arguments in registers.  */
+	movi	a3, 0		/* Used to be init.  */
+	stw 	a3, (sp, 0) 	/* Used to be fini.  */
 	lrw	a0, main
-	lrw	a3, __libc_csu_init
 	/* Let the libc call main and exit with its return code.  */
 	jsri	__libc_start_main
 
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 9720a4e446..ea3f7a69d0 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -93,6 +93,10 @@ typedef struct link_map *lookup_t;
    : (__glibc_unlikely ((ref)->st_shndx == SHN_ABS) ? 0			\
       : LOOKUP_VALUE_ADDRESS (map, map_set)) + (ref)->st_value)
 
+/* Type of a constructor function, in DT_INIT, DT_INIT_ARRAY,
+   DT_PREINIT_ARRAY.  */
+typedef void (*dl_init_t) (int, char **, char **);
+
 /* On some architectures a pointer to a function is not just a pointer
    to the actual code of the function but rather an architecture
    specific descriptor. */
@@ -101,7 +105,7 @@ typedef struct link_map *lookup_t;
  (void *) SYMBOL_ADDRESS (map, ref, false)
 # define DL_LOOKUP_ADDRESS(addr) ((ElfW(Addr)) (addr))
 # define DL_CALL_DT_INIT(map, start, argc, argv, env) \
- ((init_t) (start)) (argc, argv, env)
+ ((dl_init_t) (start)) (argc, argv, env)
 # define DL_CALL_DT_FINI(map, start) ((fini_t) (start)) ()
 #endif
 
diff --git a/sysdeps/hppa/dl-lookupcfg.h b/sysdeps/hppa/dl-lookupcfg.h
index 29d994bfc2..a9a927f26c 100644
--- a/sysdeps/hppa/dl-lookupcfg.h
+++ b/sysdeps/hppa/dl-lookupcfg.h
@@ -56,7 +56,7 @@ void attribute_hidden _dl_unmap (struct link_map *map);
 {							\
   ElfW(Addr) addr;					\
   DL_DT_FUNCTION_ADDRESS(map, start, , addr)		\
-  init_t init = (init_t) addr; 				\
+  dl_init_t init = (dl_init_t) addr; 			\
   init (argc, argv, env);				\
 }
 
diff --git a/sysdeps/hppa/start.S b/sysdeps/hppa/start.S
index 2fe73c9aae..4a1877f8e8 100644
--- a/sysdeps/hppa/start.S
+++ b/sysdeps/hppa/start.S
@@ -36,8 +36,6 @@
 	.import main, code
 	.import $global$, data
 	.import __libc_start_main, code
-	.import __libc_csu_fini, code
-	.import __libc_csu_init, code
 
 	/* Have the linker create plabel words so we get PLABEL32
 	   relocs and not 21/14.  The use of 21/14 relocs is only
@@ -52,10 +50,6 @@
 	.word P%main
 .Lp__libc_start_main:
 	.word P%__libc_start_main
-.Lp__libc_csu_fini:
-	.word P%__libc_csu_fini
-.Lp__libc_csu_init:
-	.word P%__libc_csu_init
 
 	.text
 	.align 4
@@ -77,8 +71,8 @@ _start:
 		1. r26 - Application main
 		2. r25 - argc
 		3. r24 - argv
-		4. r23 - __libc_csu_init
-		5. sp-52 - __libc_csu_fini
+		4. r23 - init (unused)
+		5. sp-52 - fini (unused)
 		6. sp-56 - rtld_fini
 		7. sp-60 - stackend  */
 
@@ -108,14 +102,6 @@ _start:
 	addil	LT'.Lpmain, %r19
 	ldw	RT'.Lpmain(%r1), %r26
 	ldw	0(%r26),%r26
-	/* void (*init) (void) (4th argument) */
-	addil	LT'.Lp__libc_csu_init, %r19
-	ldw	RT'.Lp__libc_csu_init(%r1), %r23
-	ldw	0(%r23), %r23
-	/* void (*fini) (void) (5th argument) */
-	addil	LT'.Lp__libc_csu_fini, %r19
-	ldw	RT'.Lp__libc_csu_fini(%r1), %r22
-	ldw	0(%r22), %r22
 #else
 	/* Load $global$ address into %dp */
 	ldil	L%$global$, %dp
@@ -124,13 +110,9 @@ _start:
 	/* load main (1st argument) */
 	ldil	LR'.Lpmain, %r26
 	ldw	RR'.Lpmain(%r26), %r26
-	/* void (*init) (void) (4th argument) */
-	ldil	LR'.Lp__libc_csu_init, %r23
-	ldw	RR'.Lp__libc_csu_init(%r23), %r23
-	/* void (*fini) (void) (5th argument) */
-	ldil	LR'.Lp__libc_csu_fini, %r22
-	ldw	RR'.Lp__libc_csu_fini(%r22), %r22
 #endif
+	ldi	0,%r23		/* Used to be init.  */
+	ldi	0,%r22		/* Used to be fini.  */
 	/* Store 5th argument */
 	stw	%r22, -52(%sp)
 	/* void *stack_end (7th argument) */
diff --git a/sysdeps/i386/start.S b/sysdeps/i386/start.S
index 24c806cfec..5296b27e65 100644
--- a/sysdeps/i386/start.S
+++ b/sysdeps/i386/start.S
@@ -87,11 +87,9 @@ ENTRY (_start)
 	call 1f
 	addl $_GLOBAL_OFFSET_TABLE_, %ebx
 
-	/* Push address of our own entry points to .fini and .init.  */
-	leal __libc_csu_fini@GOTOFF(%ebx), %eax
-	pushl %eax
-	leal __libc_csu_init@GOTOFF(%ebx), %eax
-	pushl %eax
+	/* This used to be the addresses of .fini and .init.  */
+	pushl $0
+	pushl $0
 
 	pushl %ecx		/* Push second argument: argv.  */
 	pushl %esi		/* Push first argument: argc.  */
@@ -112,9 +110,9 @@ ENTRY (_start)
 	   But let the libc call main.    */
 	call __libc_start_main@PLT
 #else
-	/* Push address of our own entry points to .fini and .init.  */
-	pushl $__libc_csu_fini
-	pushl $__libc_csu_init
+	/* This used to be the addresses of .fini and .init.  */
+	pushl $0
+	pushl $0
 
 	pushl %ecx		/* Push second argument: argv.  */
 	pushl %esi		/* Push first argument: argc.  */
diff --git a/sysdeps/ia64/dl-lookupcfg.h b/sysdeps/ia64/dl-lookupcfg.h
index 209d926bad..58ca32424b 100644
--- a/sysdeps/ia64/dl-lookupcfg.h
+++ b/sysdeps/ia64/dl-lookupcfg.h
@@ -50,7 +50,7 @@ extern void attribute_hidden _dl_unmap (struct link_map *map);
 {							\
   ElfW(Addr) addr;					\
   DL_DT_FUNCTION_ADDRESS(map, start, , addr)		\
-  init_t init = (init_t) addr; 				\
+  dl_init_t init = (dl_init_t) addr; 			\
   init (argc, argv, env);				\
 }
 
diff --git a/sysdeps/ia64/start.S b/sysdeps/ia64/start.S
index 0018acc821..b28f8cb429 100644
--- a/sysdeps/ia64/start.S
+++ b/sysdeps/ia64/start.S
@@ -82,20 +82,15 @@ _start:
 	{
 	  addl r11 = @ltoff(__libc_ia64_register_backing_store_base), gp
 	  addl out0 = @ltoff(@fptr(main)), gp
-	  addl out3 = @ltoff(@fptr(__libc_csu_init)), gp
+	  mov out3 = r0		/* Used to be init.  */
 	  ;;
 	}
 	{ .mmi
 	  ld8 r3 = [r11]	/* pointer to __libc_ia64_register_backing_store_base */
 	  ld8 out0 = [out0]	/* pointer to `main' function descriptor */
-	  addl out4 = @ltoff(@fptr(__libc_csu_fini)), gp
+	  mov out4 = r0		/* Used to be fini.  */
 	  ;;
 	}
-	{ .mmi
-	  ld8 out3 = [out3]	/* pointer to `init' function descriptor */
-	  ld8 out4 = [out4]	/* pointer to `fini' function descriptor */
-	  nop 0
-	}
 	.body
 	{ .mib
 	  st8 [r3] = r10
diff --git a/sysdeps/m68k/start.S b/sysdeps/m68k/start.S
index c36b34f8d9..98da4db9f3 100644
--- a/sysdeps/m68k/start.S
+++ b/sysdeps/m68k/start.S
@@ -76,15 +76,14 @@ _start:
 	pea (%a1)		/* Push address of the shared library
 				   termination function.  */
 
+	/* These used to be addresses of the .fini and .init entry points.  */
+	clr.l -(%sp)
+	clr.l -(%sp)
+
 #ifdef PIC
 	/* Load PIC register.  */
 	LOAD_GOT (%a5)
 
-	/* Push the address of our own entry points to `.fini' and
-	   `.init'.  */
-	move.l __libc_csu_fini@GOT(%a5), -(%sp)
-	move.l __libc_csu_init@GOT(%a5), -(%sp)
-
 	pea (%a0)		/* Push second argument: argv.  */
 	move.l %d0, -(%sp)	/* Push first argument: argc.  */
 
@@ -94,10 +93,6 @@ _start:
 	   let the libc call main.  */
 	jbsr __libc_start_main@PLTPC
 #else
-	/* Push the address of our own entry points to `.fini' and
-	   `.init'.  */
-	pea __libc_csu_fini
-	pea __libc_csu_init
 
 	pea (%a0)		/* Push second argument: argv.  */
 	move.l %d0, -(%sp)	/* Push first argument: argc.  */
diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist
index 509e9b7cb0..e10a286d2e 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -2203,6 +2203,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/microblaze/start.S b/sysdeps/microblaze/start.S
index dcb202a63b..6589bd4dc7 100644
--- a/sysdeps/microblaze/start.S
+++ b/sysdeps/microblaze/start.S
@@ -63,14 +63,14 @@ _start:
     mfs     r20,rpc
     addik   r20,r20,_GLOBAL_OFFSET_TABLE_+8
     lwi     r5,r20,main@GOT
-    lwi     r8,r20,__libc_csu_init@GOT
-    lwi     r9,r20,__libc_csu_fini@GOT
+    addk    r8,r0,r0		/* Used to be init.  */
+    addk    r9,r0,r0		/* Used to be fini.  */
     brid    __libc_start_main@PLT
     addk    r10,r0,r0
 #else
     addik   r5,r0,main
-    addik   r8,r0,__libc_csu_init
-    addik   r9,r0,__libc_csu_fini
+    addk    r8,r0,r0		/* Used to be init.  */
+    addk    r9,r0,r0		/* Used to be fini.  */
     brid    __libc_start_main
     addk    r10,r0,r0
 #endif
diff --git a/sysdeps/mips/start.S b/sysdeps/mips/start.S
index 28e2ed17ad..4ec42a2a7f 100644
--- a/sysdeps/mips/start.S
+++ b/sysdeps/mips/start.S
@@ -96,13 +96,13 @@ ENTRY_POINT:
 # if _MIPS_SIM == _ABIO32
 	PTR_SUBIU $29, 32
 # endif
-	PTR_LA $7, __libc_csu_init		/* init */
-	PTR_LA $8, __libc_csu_fini
+	move  $7, $0			/* Used to be init.  */
 # if _MIPS_SIM == _ABIO32
-	PTR_S $8, 16($29)		/* fini */
+	PTR_S $0, 16($29)		/* Used to be fini.  */
 	PTR_S $2, 20($29)		/* rtld_fini */
 	PTR_S $29, 24($29)		/* stack_end */
 # else
+	move $8, $0		/* Used to be fini.  */
 	move $9, $2		/* rtld_fini */
 	move $10, $29		/* stack_end */
 # endif
@@ -143,19 +143,17 @@ ENTRY_POINT:
 	/* Lay out last arguments, and call __libc_start_main().  */
 # ifdef __PIC__
 	sw	$7, 24($sp)			/* stack_end */
-	lw	$4, %got(__libc_csu_fini)($3)
-	lw	$7, %got(__libc_csu_init)($3)	/* init */
-	sw	$4, 16($sp)			/* fini */
+	move	$4, $0				/* Used to be ini.  */
+	sw	$0, 16($sp)			/* Used to be fini.  */
 	lw	$4, %got(main)($3)		/* main */
 	lw	$3, %call16(__libc_start_main)($3)
 	sw	$2, 20($sp)			/* rtld_fini */
 	move	$25, $3
 	jalr	$3
 # else
-	lw	$4, 1f
 	sw	$7, 24($sp)			/* stack_end */
-	lw	$7, 2f				/* init */
-	sw	$4, 16($sp)			/* fini */
+	move	$7, $0				/* Used to be init.  */
+	sw	$0, 16($sp)			/* Used to be fini.  */
 	lw	$4, 3f				/* main */
 	sw	$2, 20($sp)			/* rtld_fini */
 	/* Load and call __libc_start_main().  */
@@ -165,8 +163,6 @@ ENTRY_POINT:
 hlt:	b	hlt		/* Crash if somehow it does return.  */
 # ifndef __PIC__
 	.align	2
-1:	.word	__libc_csu_fini
-2:	.word	__libc_csu_init
 3:	.word	main
 4:	.word	__libc_start_main
 # endif
diff --git a/sysdeps/nios2/start.S b/sysdeps/nios2/start.S
index 0a6c587de3..7c9696977f 100644
--- a/sysdeps/nios2/start.S
+++ b/sysdeps/nios2/start.S
@@ -92,18 +92,11 @@ _start:
 	addi	r2, r2, %lo(_gp_got - 1b)
 	add	r22, r22, r2
 
-	/* Push fini */
-	movhi	r8, %call_hiadj(__libc_csu_fini)
-	addi	r8, r8, %call_lo(__libc_csu_fini)
-	add	r8, r8, r22
-	ldw	r8, 0(r8)
-	stw	r8, 0(sp)
-
-	/* r7 == init */
-	movhi	r7, %call_hiadj(__libc_csu_init)
-	addi	r7, r7, %call_lo(__libc_csu_init)
-	add	r7, r7, r22
-	ldw	r7, 0(r7)
+	/* Used to be fini.  */
+	stw	zero, 0(sp)
+
+	/* Used to be init.  */
+	mov	r7, zero
 
 	/* r6 == argv */
 	addi	r6, sp, 16
diff --git a/sysdeps/powerpc/powerpc32/start.S b/sysdeps/powerpc/powerpc32/start.S
index a721a18775..39ce1a18ff 100644
--- a/sysdeps/powerpc/powerpc32/start.S
+++ b/sysdeps/powerpc/powerpc32/start.S
@@ -52,8 +52,8 @@
 L(start_addresses):
 	.long	_SDA_BASE_
 	.long	main
-	.long 	__libc_csu_init
-	.long 	__libc_csu_fini
+	.long 	0 /* Used to be init.  */
+	.long 	0 /* Used to be fini.  */
 	ASM_SIZE_DIRECTIVE(L(start_addresses))
 
 	.section ".text"
diff --git a/sysdeps/powerpc/powerpc64/start.S b/sysdeps/powerpc/powerpc64/start.S
index 612c846632..71c0c67926 100644
--- a/sysdeps/powerpc/powerpc64/start.S
+++ b/sysdeps/powerpc/powerpc64/start.S
@@ -53,8 +53,8 @@ L(start_addresses):
 	.quad	0 /* was _SDA_BASE_  but not in 64-bit ABI*/
 /*     function descriptors so don't need JUMPTARGET */
 	.quad	main
-	.quad 	__libc_csu_init
-	.quad 	__libc_csu_fini
+	.quad 	0 /* Used to be init.  */
+	.quad 	0 /* Used to be fini.  */
 
 	ASM_SIZE_DIRECTIVE(L(start_addresses))
 
diff --git a/sysdeps/riscv/start.S b/sysdeps/riscv/start.S
index 9c94035015..806f6aacd6 100644
--- a/sysdeps/riscv/start.S
+++ b/sysdeps/riscv/start.S
@@ -54,8 +54,8 @@ ENTRY (ENTRY_POINT)
 	REG_L a1, 0(sp)      /* argc.  */
 	addi  a2, sp, SZREG  /* argv.  */
 	andi  sp, sp, ALMASK /* Align stack. */
-	lla   a3, __libc_csu_init
-	lla   a4, __libc_csu_fini
+	li    a3, 0	     /* Used to be init.  */
+	li    a4, 0	     /* Used to be fini.  */
 	mv    a6, sp  /* stack_end.  */
 
 	call  __libc_start_main@plt
diff --git a/sysdeps/s390/s390-32/start.S b/sysdeps/s390/s390-32/start.S
index aba90739c1..b6cfa4caf3 100644
--- a/sysdeps/s390/s390-32/start.S
+++ b/sysdeps/s390/s390-32/start.S
@@ -175,18 +175,16 @@ _start:
 	 */
 	stm     %r14,%r15,96(%r15)      # store rtld_fini/stack_end to parameter area
 	la      %r7,96(%r15)
-	l       %r6,.L2-.Llit(%r13)     # load pointer to __libc_csu_fini
-	l       %r5,.L1-.Llit(%r13)     # load pointer to __libc_csu_init
 	l       %r2,.L3-.Llit(%r13)     # load pointer to main
 	l       %r1,.L4-.Llit(%r13)	# load pointer to __libc_start_main
 #ifdef PIC
 	l       %r12,.L5-.Llit(%r13)    # load .got pointer
-	la	%r6,0(%r13,%r6)
-	la	%r5,0(%r13,%r5)
 	la	%r12,0(%r13,%r12)
 	l	%r2,0(%r12,%r2)
 	la	%r1,0(%r13,%r1)
 #endif
+	lhi	%r6, 0			# Used to fini.
+	lhi	%r5, 0			# Used to init.
 
 	/* ok, now branch to the libc main routine */
 	basr    %r14,%r1
@@ -197,13 +195,9 @@ _start:
 	cfi_endproc
 .Llit:
 #ifndef PIC
-.L1:    .long  __libc_csu_init
-.L2:    .long  __libc_csu_fini
 .L3:    .long  main
 .L4:    .long  __libc_start_main
 #else
-.L1:    .long  __libc_csu_init-.Llit
-.L2:    .long  __libc_csu_fini-.Llit
 .L3:    .long  main@GOT
 .L4:    .long  __libc_start_main@plt-.Llit
 .L5:    .long  _GLOBAL_OFFSET_TABLE_-.Llit
diff --git a/sysdeps/s390/s390-64/start.S b/sysdeps/s390/s390-64/start.S
index 0d9d30916d..4e6526308a 100644
--- a/sysdeps/s390/s390-64/start.S
+++ b/sysdeps/s390/s390-64/start.S
@@ -80,8 +80,8 @@ _start:
 	 */
 	stmg	%r14,%r15,160(%r15)	# store rtld_fini/stack_end to parameter area
 	la	%r7,160(%r15)
-	larl	%r6,__libc_csu_fini	# load pointer to __libc_csu_fini
-	larl	%r5,__libc_csu_init	# load pointer to __libc_csu_init
+	lghi	%r6,0			# Used to be fini.
+	lghi	%r5,0			# Used to be init.
 
 	/* Ok, now branch to the libc main routine.  */
 #ifdef PIC
diff --git a/sysdeps/sh/start.S b/sysdeps/sh/start.S
index ab29f194f7..606ee59222 100644
--- a/sysdeps/sh/start.S
+++ b/sysdeps/sh/start.S
@@ -70,12 +70,11 @@ _start:
 
 	/* Push the last arguments to main() onto the stack */
 	mov.l r4,@-r15
-	mov.l L_fini,r0
-	mov.l r0,@-r15
+	mov.l r14,@-r15		/* Used to be fini.  */
 
 	/* Set up the other arguments for main() that go in registers */
 	mov.l L_main,r4
-	mov.l L_init,r7
+	mov #0,r7		/* Used to be init.  */
 
 	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini) */
 
@@ -90,10 +89,6 @@ _start:
 	.align	2
 L_main:
 	.long	main
-L_init:
-	.long	__libc_csu_init
-L_fini:
-	.long	__libc_csu_fini
 L_libc_start_main:
 	.long	__libc_start_main
 L_abort:
diff --git a/sysdeps/sparc/sparc32/start.S b/sysdeps/sparc/sparc32/start.S
index 45ca77da3e..00bf898fb9 100644
--- a/sysdeps/sparc/sparc32/start.S
+++ b/sysdeps/sparc/sparc32/start.S
@@ -59,22 +59,14 @@ _start:
   /* Load the addresses of the user entry points.  */
 #ifndef PIC
 	sethi	%hi(main), %o0
-	sethi	%hi(__libc_csu_init), %o3
-	sethi	%hi(__libc_csu_fini), %o4
 	or	%o0, %lo(main), %o0
-	or	%o3, %lo(__libc_csu_init), %o3
-	or	%o4, %lo(__libc_csu_fini), %o4
 #else
 	sethi	%gdop_hix22(main), %o0
-	sethi	%gdop_hix22(__libc_csu_init), %o3
-	sethi	%gdop_hix22(__libc_csu_fini), %o4
 	xor	%o0, %gdop_lox10(main), %o0
-	xor	%o3, %gdop_lox10(__libc_csu_init), %o3
-	xor	%o4, %gdop_lox10(__libc_csu_fini), %o4
 	ld	[%l7 + %o0], %o0, %gdop(main)
-	ld	[%l7 + %o3], %o3, %gdop(__libc_csu_init)
-	ld	[%l7 + %o4], %o4, %gdop(__libc_csu_fini)
 #endif
+	mov	0, %o3		/* Used to be init.  */
+	mov	0, %o4		/* Used to be fini.  */
 
   /* When starting a binary via the dynamic linker, %g1 contains the
      address of the shared library termination function, which will be
diff --git a/sysdeps/sparc/sparc64/start.S b/sysdeps/sparc/sparc64/start.S
index 210fbaff90..8520717eba 100644
--- a/sysdeps/sparc/sparc64/start.S
+++ b/sysdeps/sparc/sparc64/start.S
@@ -60,22 +60,14 @@ _start:
   /* Load the addresses of the user entry points.  */
 #ifndef PIC
 	sethi	%hi(main), %o0
-	sethi	%hi(__libc_csu_init), %o3
-	sethi	%hi(__libc_csu_fini), %o4
 	or	%o0, %lo(main), %o0
-	or	%o3, %lo(__libc_csu_init), %o3
-	or	%o4, %lo(__libc_csu_fini), %o4
 #else
 	sethi	%gdop_hix22(main), %o0
-	sethi	%gdop_hix22(__libc_csu_init), %o3
-	sethi	%gdop_hix22(__libc_csu_fini), %o4
 	xor	%o0, %gdop_lox10(main), %o0
-	xor	%o3, %gdop_lox10(__libc_csu_init), %o3
-	xor	%o4, %gdop_lox10(__libc_csu_fini), %o4
 	ldx	[%l7 + %o0], %o0, %gdop(main)
-	ldx	[%l7 + %o3], %o3, %gdop(__libc_csu_init)
-	ldx	[%l7 + %o4], %o4, %gdop(__libc_csu_fini)
 #endif
+	mov	0, %o3		/* Used to be init.  */
+	mov	0, %o4		/* Used to be fini.  */
 
   /* When starting a binary via the dynamic linker, %g1 contains the
      address of the shared library termination function, which will be
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index 4cc1c6a591..bac795262d 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2171,3 +2171,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index 26ad9845e4..897f70db22 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2253,6 +2253,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist
index bb9dfd4daf..604d259ad6 100644
--- a/sysdeps/unix/sysv/linux/arc/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arc/libc.abilist
@@ -1931,3 +1931,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
index 3b0a47e967..094236f713 100644
--- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
@@ -155,6 +155,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
 GLIBC_2.4 _IO_2_1_stdin_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
index 9ab3924888..2bb4d31e81 100644
--- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
@@ -152,6 +152,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
 GLIBC_2.4 _IO_2_1_stdin_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 14a84dac8f..d4291fecfb 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2115,3 +2115,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 5c8502f3d3..1fd2a862f6 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2074,6 +2074,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index ddc5837059..943331f01e 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2241,6 +2241,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index e3b345b803..f530151bde 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2106,6 +2106,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 25f2d1c08f..6e76b6dcaa 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -156,6 +156,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0x98
 GLIBC_2.4 _IO_2_1_stdin_ D 0x98
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index c4891479d3..7541b8289f 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2186,6 +2186,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
index 143b0163b4..6cf1936c42 100644
--- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
@@ -2166,3 +2166,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
index 13d374a031..98730ebcda 100644
--- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
@@ -2163,3 +2163,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index b2295f1937..92fa6cbc73 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2157,6 +2157,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index 4c786070d0..265a49e74e 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2155,6 +2155,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index aa9c6a4dca..cfa5e1111b 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -2163,6 +2163,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index 5939588ad5..8c03ac52cd 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -2157,6 +2157,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index 92556c4237..17f5609e06 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2204,3 +2204,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-start.c b/sysdeps/unix/sysv/linux/powerpc/libc-start.c
index 66f5effe8a..4d681dad06 100644
--- a/sysdeps/unix/sysv/linux/powerpc/libc-start.c
+++ b/sysdeps/unix/sysv/linux/powerpc/libc-start.c
@@ -41,12 +41,12 @@ struct startup_info
   };
 
 int
-__libc_start_main (int argc, char **argv,
-		   char **ev,
-		   ElfW (auxv_t) * auxvec,
-		   void (*rtld_fini) (void),
-		   struct startup_info *stinfo,
-		   char **stack_on_entry)
+__libc_start_main_impl (int argc, char **argv,
+			char **ev,
+			ElfW (auxv_t) * auxvec,
+			void (*rtld_fini) (void),
+			struct startup_info *stinfo,
+			char **stack_on_entry)
 {
   /* the PPC SVR4 ABI says that the top thing on the stack will
      be a NULL pointer, so if not we assume that we're being called
@@ -99,3 +99,4 @@ __libc_start_main (int argc, char **argv,
 			     stinfo->init, stinfo->fini, rtld_fini,
 			     stack_on_entry);
 }
+DEFINE_LIBC_START_MAIN_VERSION
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index 26c93dff05..76a16e2a6d 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -2213,6 +2213,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index f04b167788..697f072fd4 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -2246,6 +2246,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
index c2ca00709e..2647bb51f1 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
@@ -2076,6 +2076,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
index 0ea50dc851..036b1c8345 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
@@ -2366,3 +2366,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
index 0263e284d4..ff3225e16f 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
@@ -1933,3 +1933,4 @@ GLIBC_2.33 wprintf F
 GLIBC_2.33 write F
 GLIBC_2.33 writev F
 GLIBC_2.33 wscanf F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index 1626c5351f..fb5ad9909f 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2133,3 +2133,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index a66426eb4d..cead75acc5 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2211,6 +2211,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index ab351873ae..31366dd7e6 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -2112,6 +2112,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/sh/be/libc.abilist b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
index 22ceaa3d87..a3a8be8910 100644
--- a/sysdeps/unix/sysv/linux/sh/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
@@ -2081,6 +2081,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/sh/le/libc.abilist b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
index d36f228192..8f505c5045 100644
--- a/sysdeps/unix/sysv/linux/sh/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
@@ -2078,6 +2078,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index 59b4313280..53ef6304f1 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -2202,6 +2202,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index 266dcdfa08..eba0cb156d 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -2129,6 +2129,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 2744bba4af..17ce5dfd58 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -2088,6 +2088,7 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index ce2f4fb72b..17a1c83903 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2185,3 +2185,4 @@ GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
+GLIBC_2.34 __libc_start_main F
diff --git a/sysdeps/x86_64/start.S b/sysdeps/x86_64/start.S
index 30fc9007c9..1b3e36826b 100644
--- a/sysdeps/x86_64/start.S
+++ b/sysdeps/x86_64/start.S
@@ -96,17 +96,13 @@ ENTRY (_start)
 	   which grow downwards).  */
 	pushq %rsp
 
-#ifdef PIC
-	/* Pass address of our own entry points to .fini and .init.  */
-	mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP
-	mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP
+	/* These used to be the addresses of .fini and .init.  */
+	xorl %r8d, %r8d
+	xorl %ecx, %ecx
 
+#ifdef PIC
 	mov main@GOTPCREL(%rip), %RDI_LP
 #else
-	/* Pass address of our own entry points to .fini and .init.  */
-	mov $__libc_csu_fini, %R8_LP
-	mov $__libc_csu_init, %RCX_LP
-
 	mov $main, %RDI_LP
 #endif