Introduce ELF_INITFINI for all architectures
Commit Message
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.
+++ 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 */
Comments
On 06/23/2018 11:45 PM, Florian Weimer wrote:
> 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.
Ping?
<https://sourceware.org/ml/libc-alpha/2018-07/msg00051.html>
Thanks,
Florian
On Wed, 08 Aug 2018 07:42:27 PDT (-0700), fweimer@redhat.com wrote:
> On 06/23/2018 11:45 PM, Florian Weimer wrote:
>> 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.
>
> Ping?
>
> <https://sourceware.org/ml/libc-alpha/2018-07/msg00051.html>
I'm happy with the RISC-V aspects, which I understand to be functionally a NOP.
I like avoiding the ABI bloat.
For some reason I thought someone mentioned some references to _init/_fini
floating around our port, but I can't find any so maybe I'm just going crazy?
If they're there then we should probably remove them, as they don't actually do
anything.
On 08/08/2018 09:49 PM, Palmer Dabbelt wrote:
> On Wed, 08 Aug 2018 07:42:27 PDT (-0700), fweimer@redhat.com wrote:
>> On 06/23/2018 11:45 PM, Florian Weimer wrote:
>>> 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.
>>
>> Ping?
>>
>> <https://sourceware.org/ml/libc-alpha/2018-07/msg00051.html>
>
> I'm happy with the RISC-V aspects, which I understand to be functionally
> a NOP. I like avoiding the ABI bloat.
>
> For some reason I thought someone mentioned some references to
> _init/_fini floating around our port, but I can't find any so maybe I'm
> just going crazy? If they're there then we should probably remove them,
> as they don't actually do anything.
The patch removes the DT_INIT/DT_FINI execution logic from the RISC-V
port because ELF_INITFINI && l->l_info[DT_FINI] != NULL and the similar
condition for DT_INIT are always false. Before the patch, the code is
still there, but dormant because the GNU toolchain will always generate
NULL pointers there.
Thanks,
Florian
On Wed, 08 Aug 2018 12:55:57 PDT (-0700), fweimer@redhat.com wrote:
> On 08/08/2018 09:49 PM, Palmer Dabbelt wrote:
>> On Wed, 08 Aug 2018 07:42:27 PDT (-0700), fweimer@redhat.com wrote:
>>> On 06/23/2018 11:45 PM, Florian Weimer wrote:
>>>> 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.
>>>
>>> Ping?
>>>
>>> <https://sourceware.org/ml/libc-alpha/2018-07/msg00051.html>
>>
>> I'm happy with the RISC-V aspects, which I understand to be functionally
>> a NOP. I like avoiding the ABI bloat.
>>
>> For some reason I thought someone mentioned some references to
>> _init/_fini floating around our port, but I can't find any so maybe I'm
>> just going crazy? If they're there then we should probably remove them,
>> as they don't actually do anything.
>
> The patch removes the DT_INIT/DT_FINI execution logic from the RISC-V
> port because ELF_INITFINI && l->l_info[DT_FINI] != NULL and the similar
> condition for DT_INIT are always false. Before the patch, the code is
> still there, but dormant because the GNU toolchain will always generate
> NULL pointers there.
Ah, thanks!
@@ -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
@@ -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)
@@ -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);
}
@@ -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. */
@@ -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
similarity index 80%
rename from sysdeps/init_array/crti.S
rename to 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. */
similarity index 82%
rename from sysdeps/init_array/crtn.S
rename to 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
new file mode 100644
@@ -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 */
deleted file mode 100644
@@ -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>
deleted file mode 100644
@@ -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>
@@ -1,5 +1,3 @@
-init_array
-
ieee754/ldbl-128
ieee754/dbl-64
ieee754/flt-32
similarity index 70%
rename from sysdeps/init_array/pt-crti.S
rename to sysdeps/riscv/platform-params.h