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[PATCH] Introduce ELF_INITFINI for all architectures
- From: fweimer at redhat dot com (Florian Weimer)
- To: libc-alpha at sourceware dot org
- Date: Sat, 23 Jun 2018 23:45:21 +0200
- Subject: [PATCH] Introduce ELF_INITFINI for all architectures
This supersedes the init_array sysdeps directory. It allows us to
check for ELF_INITFINI in both C and assembler code, and skip DT_INIT
and DT_FINI processing completely on RISC-V.
A new header file is needed because <dl-machine.h> is incompatible
with assembler code. <sysdep.h> is compatible with assembler code,
but it cannot be included in all assembler files because on some
architectures, it redefines register names, and some assembler files
conflict with that.
2018-06-23 Florian Weimer <fweimer@redhat.com>
Introduce ELF_INITFINI, set everywhere except on RISC-V.
* sysdeps/init_array/crti.S: Move to ...
* sysdepes/generic/crti.S: here. Report an error if ELF_INITFINI.
* sysdeps/init_array/crtn.S: Move to ...
* sysdeps/generic/crtn.S: here. Report an error if ELF_INITFINI.
* csu/elf-init.c: Check ELF_INITFINI instead of NO_INITFINI.
* gmon/gmon-start.c [!ELF_INITFINI] (GMON_START_ARRAY_SECTION):
Define.
* elf/dl-fini.c (_dl_fini): Check for ELF_INITFINI before using
DT_FINI.
* elf/dl-init.c (call_init): Check for ELF_INITFINI before using
DT_INIT.
* nptl/pt-crti.S [ELF_INITFINI]: Use .init_array instead of
PREINIT_FUNCTION.
* sysdeps/generic/platform-params.h: New file.
* sysdeps/init_array/elf-init.c: Remove file.
* sysdeps/init_array/gmon-start.c: Likewise.
* sysdeps/init_array/pt-crti.S: Likewise.
* sysdeps/riscv/Implies (init_array): Remove.
* sysdeps/riscv/platform-params.h: New file.
diff --git a/csu/elf-init.c b/csu/elf-init.c
index da59b2c77b..8bde25a340 100644
--- a/csu/elf-init.c
+++ b/csu/elf-init.c
@@ -34,6 +34,7 @@
<http://www.gnu.org/licenses/>. */
#include <stddef.h>
+#include <platform-params.h>
/* These magic symbols are provided by the linker. */
@@ -49,7 +50,7 @@ extern void (*__fini_array_start []) (void) attribute_hidden;
extern void (*__fini_array_end []) (void) attribute_hidden;
-#ifndef NO_INITFINI
+#if ELF_INITFINI
/* These function symbols are provided for the .init/.fini section entry
points automagically by the linker. */
extern void _init (void);
@@ -79,7 +80,7 @@ __libc_csu_init (int argc, char **argv, char **envp)
}
#endif
-#ifndef NO_INITFINI
+#if ELF_INITFINI
_init ();
#endif
@@ -99,7 +100,7 @@ __libc_csu_fini (void)
while (i-- > 0)
(*__fini_array_start [i]) ();
-# ifndef NO_INITFINI
+# if ELF_INITFINI
_fini ();
# endif
#endif
diff --git a/csu/gmon-start.c b/csu/gmon-start.c
index 6a130890a9..f9fbdbfed8 100644
--- a/csu/gmon-start.c
+++ b/csu/gmon-start.c
@@ -37,6 +37,7 @@
#include <sys/gmon.h>
#include <stdlib.h>
#include <unistd.h>
+#include <platform-params.h>
#define __ASSEMBLY__
#include <entry.h>
@@ -59,6 +60,13 @@ extern char etext[];
# endif
#endif
+#if !ELF_INITFINI
+/* Instead of defining __gmon_start__ globally in gcrt1.o, we make it
+ static and just put a pointer to it into the .preinit_array
+ section. */
+# define GMON_START_ARRAY_SECTION ".preinit_array"
+#endif
+
#ifdef GMON_START_ARRAY_SECTION
static void __gmon_start__ (void);
static void (*const gmon_start_initializer) (void)
diff --git a/elf/dl-fini.c b/elf/dl-fini.c
index 3cfc262400..20c5581525 100644
--- a/elf/dl-fini.c
+++ b/elf/dl-fini.c
@@ -19,6 +19,7 @@
#include <assert.h>
#include <string.h>
#include <ldsodefs.h>
+#include <platform-params.h>
/* Type of the constructor functions. */
@@ -117,7 +118,7 @@ _dl_fini (void)
/* Is there a destructor function? */
if (l->l_info[DT_FINI_ARRAY] != NULL
- || l->l_info[DT_FINI] != NULL)
+ || (ELF_INITFINI && l->l_info[DT_FINI] != NULL))
{
/* When debugging print a message first. */
if (__builtin_expect (GLRO(dl_debug_mask)
@@ -139,7 +140,7 @@ _dl_fini (void)
}
/* Next try the old-style destructor. */
- if (l->l_info[DT_FINI] != NULL)
+ if (ELF_INITFINI && l->l_info[DT_FINI] != NULL)
DL_CALL_DT_FINI
(l, l->l_addr + l->l_info[DT_FINI]->d_un.d_ptr);
}
diff --git a/elf/dl-init.c b/elf/dl-init.c
index 3e72fa3013..31eb12b974 100644
--- a/elf/dl-init.c
+++ b/elf/dl-init.c
@@ -18,6 +18,7 @@
#include <stddef.h>
#include <ldsodefs.h>
+#include <platform-params.h>
/* Type of the initializer. */
@@ -40,9 +41,10 @@ call_init (struct link_map *l, int argc, char **argv, char **env)
&& l->l_type == lt_executable)
return;
+ bool have_init = ELF_INITFINI && l->l_info[DT_INIT] != NULL;
+
/* Are there any constructors? */
- if (l->l_info[DT_INIT] == NULL
- && __builtin_expect (l->l_info[DT_INIT_ARRAY] == NULL, 1))
+ if (!have_init && __builtin_expect (l->l_info[DT_INIT_ARRAY] == NULL, 1))
return;
/* Print a debug message if wanted. */
@@ -54,7 +56,7 @@ call_init (struct link_map *l, int argc, char **argv, char **env)
- the one named by DT_INIT
- the others in the DT_INIT_ARRAY.
*/
- if (l->l_info[DT_INIT] != NULL)
+ if (have_init)
DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr, argc, argv, env);
/* Next see whether there is an array with initialization functions. */
diff --git a/nptl/pt-crti.S b/nptl/pt-crti.S
index a0deb9979c..efd28c8f7e 100644
--- a/nptl/pt-crti.S
+++ b/nptl/pt-crti.S
@@ -33,11 +33,18 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#include <platform-params.h>
+
/* Arrange for __pthread_initialize_minimal_internal to be called at
libpthread startup, instead of conditionally calling
__gmon_start__. */
-#define PREINIT_FUNCTION __pthread_initialize_minimal_internal
-#define PREINIT_FUNCTION_WEAK 0
+#if ELF_INITFINI
+# define PREINIT_FUNCTION __pthread_initialize_minimal_internal
+# define PREINIT_FUNCTION_WEAK 0
-#include <crti.S>
+# include <crti.S>
+#else
+ .section .init_array,"a",%init_array
+ .dc.a __pthread_initialize_minimal_internal
+#endif
diff --git a/sysdeps/init_array/crti.S b/sysdeps/generic/crti.S
similarity index 80%
rename from sysdeps/init_array/crti.S
rename to sysdeps/generic/crti.S
+++ b/sysdeps/generic/crti.S
@@ -12,11 +12,17 @@
toolchains without .init_array support can use this to avoid the
superfluous .init and .fini boilerplate code. */
+#include <platform-params.h>
+
+#if ELF_INITFINI
+# error Cannot use default crti.S because it lacks _init code
+#endif
+
#ifdef PREINIT_FUNCTION
-#if PREINIT_FUNCTION_WEAK
-# error PREINIT_FUNCTION_WEAK is unsupported
-#endif
+# if PREINIT_FUNCTION_WEAK
+# error PREINIT_FUNCTION_WEAK is unsupported
+# endif
/* This arranges for PREINIT_FUNCTION to be called upon loading a library that
contains crti.o. */
diff --git a/sysdeps/init_array/crtn.S b/sysdeps/generic/crtn.S
similarity index 82%
rename from sysdeps/init_array/crtn.S
rename to sysdeps/generic/crtn.S
+++ b/sysdeps/generic/crtn.S
@@ -11,3 +11,9 @@
But new configurations without compatibility concerns for
toolchains without .init_array support can use this to avoid the
superfluous .init and .fini boilerplate code. */
+
+#include <platform-params.h>
+
+#if ELF_INITFINI
+# error Cannot use genetric crtn.S because it lacks _fini code
+#endif
diff --git a/sysdeps/generic/platform-params.h b/sysdeps/generic/platform-params.h
new file mode 100644
index 0000000000..5a732fa02f
--- /dev/null
+++ b/sysdeps/generic/platform-params.h
@@ -0,0 +1,32 @@
+/* Various definitions for specifying platform behavior. Generic version.
+ Copyright (C) 2018 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This file contains definitions specifying behavior of a platform
+ (CPU + kernel) combination. It must be usable from both assembler
+ sources and C sources. Definitions should be namespace-clean. */
+
+#ifndef _PLATFORM_PARAMS_H
+#define _PLATFORM_PARAMS_H
+
+/* Most platforms use _init/_fini symbols to call constructors and
+ destructors. If defined to 0, the dynamic loader will ignore
+ DT_INIT and DT_FINI tags, and static binaries will not call the
+ _init or _fini functions. */
+#define ELF_INITFINI 1
+
+#endif /* _PLATFORM_PARAMS_H */
diff --git a/sysdeps/init_array/elf-init.c b/sysdeps/init_array/elf-init.c
deleted file mode 100644
index 9fbe82e93c..0000000000
--- a/sysdeps/init_array/elf-init.c
+++ /dev/null
@@ -1,37 +0,0 @@
-/* Startup support for ELF initializers/finalizers in the main executable.
- Copyright (C) 2013-2018 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
- <http://www.gnu.org/licenses/>. */
-
-#define NO_INITFINI
-#include <csu/elf-init.c>
diff --git a/sysdeps/init_array/gmon-start.c b/sysdeps/init_array/gmon-start.c
deleted file mode 100644
index 3bacaf7e38..0000000000
--- a/sysdeps/init_array/gmon-start.c
+++ /dev/null
@@ -1,41 +0,0 @@
-/* gmon startup hook using .preinit_array.
- Copyright (C) 2013-2018 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
- <http://www.gnu.org/licenses/>. */
-
-/* Instead of defining __gmon_start__ globally in gcrt1.o, we make it
- static and just put a pointer to it into the .preinit_array section. */
-
-#define GMON_START_ARRAY_SECTION ".preinit_array"
-
-#include <csu/gmon-start.c>
diff --git a/sysdeps/riscv/Implies b/sysdeps/riscv/Implies
index c88325b8be..1945b1f4bb 100644
--- a/sysdeps/riscv/Implies
+++ b/sysdeps/riscv/Implies
@@ -1,5 +1,3 @@
-init_array
-
ieee754/ldbl-128
ieee754/dbl-64
ieee754/flt-32
diff --git a/sysdeps/init_array/pt-crti.S b/sysdeps/riscv/platform-params.h
similarity index 70%
rename from sysdeps/init_array/pt-crti.S
rename to sysdeps/riscv/platform-params.h
+++ b/sysdeps/riscv/platform-params.h
@@ -1,5 +1,5 @@
-/* Special initializer support for libpthread.
- Copyright (C) 2015-2018 Free Software Foundation, Inc.
+/* Various definitions for specifying platform behavior. RISC_V version.
+ Copyright (C) 2018 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
@@ -16,8 +16,10 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* This arranges for libpthread.so's special initializer to be called as
- soon as the library is loaded. */
+#ifndef _PLATFORM_PARAMS_H
+#define _PLATFORM_PARAMS_H
- .section .init_array,"a",%init_array
- .dc.a __pthread_initialize_minimal_internal
+/* RISC-V does not have .init/.fini. */
+#define ELF_INITFINI 0
+
+#endif /* _PLATFORM_PARAMS_H */