elf: Fix dynamic-link.h usage on rtld.c

The 4af6982e4c fix does not fully handle RTLD_BOOTSTRAP usage on
rtld.c due two issues:

  1. RTLD_BOOTSTRAP is also used on dl-machine.h on various
     architectures and it changes the semantics of various machine
     relocation functions.

  2. The elf_get_dynamic_info() change was done sideways, previously
     to 490e6c62aa get-dynamic-info.h was included by the first
     dynamic-link.h include *without* RTLD_BOOTSTRAP being defined.
     It means that the code within elf_get_dynamic_info() that uses
     RTLD_BOOTSTRAP is in fact unused.

To fix 1. this patch now includes dynamic-link.h only once with
RTLD_BOOTSTRAP defined.  The ELF_DYNAMIC_RELOCATE call will now have
the relocation fnctions with the expected semantics for the loader.

And to fix 2. part of 4af6982e4c is reverted (the check argument
elf_get_dynamic_info() is not required) and the RTLD_BOOTSTRAP
pieces are removed.

To reorganize the includes the static TLS definition is moved to
its own header to avoid a circular dependency (it is defined on
dynamic-link.h and dl-machine.h requires it at same time other
dynamic-link.h definition requires dl-machine.h defitions).

Also ELF_MACHINE_NO_REL, ELF_MACHINE_NO_RELA, and ELF_MACHINE_PLT_REL
are moved to its own header.  Only ancient ABIs need special values
(arm, i386, and mips), so a generic one is used as default.

The powerpc Elf64_FuncDesc is also moved to its own header, since
csu code required its definition (which would require either include
elf/ folder or add a full path with elf/).

Checked on x86_64, i686, aarch64, armhf, powerpc64, powerpc32,
and powerpc64le.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>

2 files changed, 33 insertions, 9 deletions

diff --git a/sysdeps/arm/dl-machine-rel.h b/sysdeps/arm/dl-machine-rel.h
new file mode 100644
index 0000000000..bec114706c
--- /dev/null
+++ b/sysdeps/arm/dl-machine-rel.h
@@ -0,0 +1,31 @@
+/* ELF dynamic relocation type supported by the architecture.  ARM version.
+   Copyright (C) 2001-2021 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.
+
+   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/>.  */
+
+#ifndef _DL_MACHINE_REL_H
+#define _DL_MACHINE_REL_H
+
+/* ARM never uses Elf32_Rela relocations for the dynamic linker.
+   Prelinked libraries may use Elf32_Rela though.  */
+#define ELF_MACHINE_NO_RELA defined RTLD_BOOTSTRAP
+#define ELF_MACHINE_NO_REL 0
+
+/* ARM never uses Elf32_Rela relocations for the dynamic linker.
+   Prelinked libraries may use Elf32_Rela though.  */
+#define ELF_MACHINE_PLT_REL 1
+
+#endif
diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h
index dfa05eee44..c758bba169 100644
--- a/sysdeps/arm/dl-machine.h
+++ b/sysdeps/arm/dl-machine.h
@@ -26,6 +26,8 @@
 #include <tls.h>
 #include <dl-tlsdesc.h>
 #include <dl-irel.h>
+#include <dl-static-tls.h>
+#include <dl-machine-rel.h>
 
 #ifndef CLEAR_CACHE
 # error CLEAR_CACHE definition required to handle TEXTREL
@@ -231,10 +233,6 @@ _dl_start_user:\n\
 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
 #define ELF_MACHINE_JMP_SLOT	R_ARM_JUMP_SLOT
 
-/* ARM never uses Elf32_Rela relocations for the dynamic linker.
-   Prelinked libraries may use Elf32_Rela though.  */
-#define ELF_MACHINE_PLT_REL 1
-
 /* We define an initialization functions.  This is called very early in
    _dl_sysdep_start.  */
 #define DL_PLATFORM_INIT dl_platform_init ()
@@ -267,11 +265,6 @@ elf_machine_plt_value (struct link_map *map, const Elf32_Rel *reloc,
 #endif /* !dl_machine_h */
 
 
-/* ARM never uses Elf32_Rela relocations for the dynamic linker.
-   Prelinked libraries may use Elf32_Rela though.  */
-#define ELF_MACHINE_NO_RELA defined RTLD_BOOTSTRAP
-#define ELF_MACHINE_NO_REL 0
-
 /* Names of the architecture-specific auditing callback functions.  */
 #define ARCH_LA_PLTENTER arm_gnu_pltenter
 #define ARCH_LA_PLTEXIT arm_gnu_pltexit