csu: move common code to libc

Why? Most trivial point, it shaves around 600 bytes from the dynamic
binaries on amd64. Less trivial, the removed code is no longer part of
the ABI, and we can ship updates to it with libc updates. Right now most
of the csu is linked into the binaries and require us to do somewhat
tricky ABI compat when it needs to change. For instance, the init_array
change would be much simpler and does not require note tagging if we
have init calling code in libc.

This could be improved more, by splitting dynamic and static
initialization. For instance, &_DYNAMIC tests can be removed then.
Such change, nonetheless, would require building libc three times.
I left this for later, after this change stabilizes, if ever.

Reviewed by:	markj
Discussed with:	jrtc27 (some objections, see the review), imp
Tested by:	markj (aarch64)
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
Differential revision:	https://reviews.freebsd.org/D37220

lib/csu/aarch64/Makefile

@@ -3,7 +3,6 @@
 .PATH: ${.CURDIR:H}/common
 
 CFLAGS+=	-I${.CURDIR}
-CFLAGS+=	-DCRT_IRELOC_RELA
 
 CRT1OBJS+=	crt1_s.o
 

lib/csu/aarch64/crt1_c.c

@@ -32,42 +32,19 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-
 #include "libc_private.h"
-#include "ignore_init.c"
+#include "csu_common.h"
 
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
-
-extern long * _end;
-
-void __start(int, char **, char **, void (*)(void));
+void __start(int, char **, char **, void (*)(void)) __dead2;
 
 /* The entry function. */
 void
 __start(int argc, char *argv[], char *env[], void (*cleanup)(void))
 {
-
-	handle_argv(argc, argv, env);
-
-	if (&_DYNAMIC != NULL)
-		atexit(cleanup);
-	else {
-		process_irelocs();
-		_init_tls();
-	}
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
 __asm__("eprol:");
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }

lib/csu/amd64/Makefile

@@ -3,6 +3,6 @@
 .PATH: ${.CURDIR:H}/common
 
 CFLAGS+=	-I${.CURDIR}
-CFLAGS+=	-fno-omit-frame-pointer -DCRT_IRELOC_RELA
+CFLAGS+=	-fno-omit-frame-pointer
 
 .include <bsd.lib.mk>

lib/csu/amd64/crt1_c.c

@@ -29,19 +29,10 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-
 #include "libc_private.h"
-#include "ignore_init.c"
+#include "csu_common.h"
 
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
-
-void _start(char **, void (*)(void));
+void _start(char **, void (*)(void)) __dead2;
 
 /* The entry function. */
 void
@@ -54,21 +45,10 @@ _start(char **ap, void (*cleanup)(void))
 	argc = *(long *)(void *)ap;
 	argv = ap + 1;
 	env = ap + 2 + argc;
-	handle_argv(argc, argv, env);
-
-	if (&_DYNAMIC != NULL) {
-		atexit(cleanup);
-	} else {
-		process_irelocs();
-		_init_tls();
-	}
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
 __asm__("eprol:");
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }

lib/csu/arm/Makefile

@@ -2,8 +2,6 @@
 
 .PATH: ${.CURDIR:H}/common
 
-CFLAGS+=	-DCRT_IRELOC_SUPPRESS
-
 CRT1OBJS+=	crt1_s.o
 
 .include <bsd.lib.mk>

lib/csu/arm/crt1_c.c

@@ -46,50 +46,33 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/elf_common.h>
-#include <stdlib.h>
 
 #include "libc_private.h"
-#include "ignore_init.c"
+#include "csu_common.h"
 
 struct Struct_Obj_Entry;
 struct ps_strings;
 
-extern void _start(int, char **, char **, const struct Struct_Obj_Entry *,
-    void (*)(void), struct ps_strings *);
-
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
+void _start(int, char **, char **, const struct Struct_Obj_Entry *,
+    void (*)(void), struct ps_strings *) __dead2;
 
 struct ps_strings *__ps_strings;
 
 void __start(int, char **, char **, struct ps_strings *,
-    const struct Struct_Obj_Entry *, void (*)(void));
+    const struct Struct_Obj_Entry *, void (*)(void)) __dead2;
 
-/* ARGSUSED */
 void
 __start(int argc, char **argv, char **env, struct ps_strings *ps_strings,
     const struct Struct_Obj_Entry *obj __unused, void (*cleanup)(void))
 {
-
-	handle_argv(argc, argv, env);
-
 	if (ps_strings != (struct ps_strings *)0)
 		__ps_strings = ps_strings;
 
-	if (&_DYNAMIC != NULL)
-		atexit(cleanup);
-	else
-		_init_tls();
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }
 
 #ifdef GCRT

lib/csu/common/csu_common.h

@@ -0,0 +1,50 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright 1996-1998 John D. Polstra.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef _CSU_COMMON_H_
+
+/*
+ * This file includes both definitions and declarations, it can be
+ * included only into one compilation unit for csu objects.  We cannot
+ * practically check this, but at least guard against
+ * double-inclusion.
+ */
+#error "Include this file only once"
+#else
+#define _CSU_COMMON_H_
+
+char **environ;
+const char *__progname = "";
+
+#ifdef GCRT
+extern int eprol;
+extern int etext;
+#endif
+
+int main(int, char **, char **);
+
+#endif	/* _CSU_COMMON_H_ */

lib/csu/i386/Makefile

@@ -3,7 +3,6 @@
 .PATH: ${.CURDIR:H}/common
 
 CFLAGS+=	-I${.CURDIR}
-CFLAGS+=	-DCRT_IRELOC_REL
 
 CRT1OBJS+=	crt1_s.o
 

lib/csu/i386/crt1_c.c

@@ -29,20 +29,10 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-
 #include "libc_private.h"
-#include "ignore_init.c"
-
-extern void _start(char *, ...);
-
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
+#include "csu_common.h"
 
+void _start(char *, ...);
 void _start1(void (*)(void), int, char *[]) __dead2;
 
 /* The entry function, C part. */
@@ -52,22 +42,12 @@ _start1(void (*cleanup)(void), int argc, char *argv[])
 	char **env;
 
 	env = argv + argc + 1;
-	handle_argv(argc, argv, env);
-	if (&_DYNAMIC != NULL) {
-		atexit(cleanup);
-	} else {
-		process_irelocs();
-		_init_tls();
-	}
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
 __asm__("eprol:");
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }
 
 __asm(".hidden	_start1");

lib/csu/powerpc/Makefile

@@ -3,6 +3,5 @@
 .PATH: ${.CURDIR:H}/common
 
 OBJS+=		crtsavres.o
-CFLAGS+=	-DCRT_IRELOC_SUPPRESS
 
 .include <bsd.lib.mk>

lib/csu/powerpc/crt1_c.c

@@ -47,22 +47,15 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 
 #include "libc_private.h"
-#include "ignore_init.c"
+#include "csu_common.h"
 
 struct Struct_Obj_Entry;
 struct ps_strings;
 
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
-
 struct ps_strings *__ps_strings;
 
 void _start(int, char **, char **, const struct Struct_Obj_Entry *,
-    void (*)(void), struct ps_strings *);
+    void (*)(void), struct ps_strings *) __dead2;
 
 /* The entry function. */
 /*
@@ -75,25 +68,14 @@ _start(int argc, char **argv, char **env,
     const struct Struct_Obj_Entry *obj __unused, void (*cleanup)(void),
     struct ps_strings *ps_strings)
 {
-
-
-	handle_argv(argc, argv, env);
-
 	if (ps_strings != (struct ps_strings *)0)
 		__ps_strings = ps_strings;
 
-	if (&_DYNAMIC != NULL)
-		atexit(cleanup);
-	else
-		_init_tls();
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }
 
 #ifdef GCRT

lib/csu/powerpc64/Makefile

@@ -4,7 +4,7 @@
 
 OBJS+=		crtsavres.o
 CFLAGS+=	-I${.CURDIR} \
-		-mlongcall -DCRT_IRELOC_RELA
+		-mlongcall
 
 CLEANFILES+=	crtsavres.S
 

lib/csu/powerpc64/crt1_c.c

@@ -44,87 +44,38 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
 #include <stdint.h>
 #include <sys/elf.h>
 
-static uint32_t cpu_features;
-static uint32_t cpu_features2;
-
 #include "libc_private.h"
-#include "ignore_init.c"
+#include "csu_common.h"
 
 struct Struct_Obj_Entry;
 struct ps_strings;
 
-extern void _start(int, char **, char **, const struct Struct_Obj_Entry *,
-    void (*)(void), struct ps_strings *);
-
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
+void _start(int, char **, char **, const struct Struct_Obj_Entry *,
+    void (*)(void), struct ps_strings *) __dead2;
 
 struct ps_strings *__ps_strings;
 
-static void
-init_cpu_features(char **env)
-{
-	const Elf_Auxinfo *aux;
-
-	/* Find the auxiliary vector on the stack. */
-	while (*env++ != 0)	/* Skip over environment, and NULL terminator */
-		;
-	aux = (const Elf_Auxinfo *)env;
-
-	/* Digest the auxiliary vector. */
-	for (;  aux->a_type != AT_NULL; aux++) {
-		switch (aux->a_type) {
-		case AT_HWCAP:
-			cpu_features = (uint32_t)aux->a_un.a_val;
-			break;
-		case AT_HWCAP2:
-			cpu_features2 = (uint32_t)aux->a_un.a_val;
-			break;
-		}
-	}
-}
-
-
 /* The entry function. */
 /*
  * First 5 arguments are specified by the PowerPC SVR4 ABI.
  * The last argument, ps_strings, is a BSD extension.
  */
-/* ARGSUSED */
 void
 _start(int argc, char **argv, char **env,
     const struct Struct_Obj_Entry *obj __unused, void (*cleanup)(void),
     struct ps_strings *ps_strings)
 {
-
-	handle_argv(argc, argv, env);
-
 	if (ps_strings != (struct ps_strings *)0)
 		__ps_strings = ps_strings;
 
-	if (&_DYNAMIC != NULL)
-		atexit(cleanup);
-	else {
-		init_cpu_features(env);
-		process_irelocs();
-		_init_tls();
-	}
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }
 
 #ifdef GCRT

lib/csu/riscv/Makefile

@@ -2,8 +2,6 @@
 
 .PATH: ${.CURDIR:H}/common
 
-CFLAGS+=	-DCRT_IRELOC_SUPPRESS
-
 CRT1OBJS+=	crt1_s.o
 
 .include <bsd.lib.mk>

lib/csu/riscv/crt1_c.c

@@ -36,37 +36,18 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-#include <stdlib.h>
-
 #include "libc_private.h"
-#include "ignore_init.c"
+#include "csu_common.h"
 
-#ifdef GCRT
-extern void _mcleanup(void);
-extern void monstartup(void *, void *);
-extern int eprol;
-extern int etext;
-#endif
-
-void __start(int argc, char **argv, char **env, void (*cleanup)(void));
+void __start(int argc, char **argv, char **env, void (*cleanup)(void)) __dead2;
 
 void
 __start(int argc, char **argv, char **env, void (*cleanup)(void))
 {
-
-	handle_argv(argc, argv, env);
-
-	if (&_DYNAMIC != NULL)
-		atexit(cleanup);
-	else
-		_init_tls();
-
 #ifdef GCRT
-	atexit(_mcleanup);
-	monstartup(&eprol, &etext);
+	__libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext);
 __asm__("eprol:");
+#else
+	__libc_start1(argc, argv, env, cleanup, main);
 #endif
-
-	handle_static_init(argc, argv, env);
-	exit(main(argc, argv, env));
 }

lib/libc/Makefile

@@ -93,6 +93,7 @@ MIASM=
 NOASM=
 
 .include "${LIBC_SRCTOP}/${LIBC_ARCH}/Makefile.inc"
+.include "${LIBC_SRCTOP}/csu/Makefile.inc"
 .include "${LIBC_SRCTOP}/db/Makefile.inc"
 .include "${LIBC_SRCTOP}/compat-43/Makefile.inc"
 .include "${LIBC_SRCTOP}/gdtoa/Makefile.inc"

lib/libc/csu/Makefile.inc

@@ -0,0 +1,10 @@
+#
+
+.PATH: ${LIBC_SRCTOP}/csu
+.include "${LIBC_SRCTOP}/csu/${LIBC_ARCH}/Makefile.inc"
+
+SRCS+= \
+	 ignore_init.c
+
+CFLAGS+= -I${LIBC_SRCTOP}/csu/${LIBC_ARCH}
+SYM_MAPS+=${LIBC_SRCTOP}/csu/Symbol.map

lib/libc/csu/Symbol.map

@@ -0,0 +1,4 @@
+FBSD_1.7 {
+	__libc_start1;
+	__libc_start1_gcrt;
+};

lib/libc/csu/aarch64/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_RELA \
+		-DINIT_IRELOCS=""

lib/libc/csu/amd64/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_RELA \
+		-DINIT_IRELOCS=""

lib/libc/csu/arm/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_SUPPRESS \
+		-DINIT_IRELOCS=""

lib/libc/csu/i386/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_REL \
+		-DINIT_IRELOCS=""

lib/libc/csu/ignore_init.c

@@ -2,7 +2,7 @@
  * SPDX-License-Identifier: BSD-1-Clause
  *
  * Copyright 2012 Konstantin Belousov <kib@FreeBSD.org>
- * Copyright (c) 2018 The FreeBSD Foundation
+ * Copyright (c) 2018, 2023 The FreeBSD Foundation
  *
  * Parts of this software was developed by Konstantin Belousov
  * <kib@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
@@ -25,14 +25,11 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
 #include <sys/param.h>
 #include <sys/elf.h>
 #include <sys/elf_common.h>
-
-extern int main(int, char **, char **);
+#include <stdlib.h>
+#include "libc_private.h"
 
 extern void (*__preinit_array_start[])(int, char **, char **) __hidden;
 extern void (*__preinit_array_end[])(int, char **, char **) __hidden;
@@ -79,9 +76,6 @@ process_irelocs(void)
 #error "Define platform reloc type"
 #endif
 
-char **environ;
-const char *__progname = "";
-
 static void
 finalizer(void)
 {
@@ -97,7 +91,7 @@ finalizer(void)
 	_fini();
 }
 
-static inline void
+static void
 handle_static_init(int argc, char **argv, char **env)
 {
 	void (*fn)(int, char **, char **);
@@ -123,7 +117,9 @@ handle_static_init(int argc, char **argv, char **env)
 	}
 }
 
-static inline void
+extern char **environ;
+
+static void
 handle_argv(int argc, char *argv[], char **env)
 {
 	const char *s;
@@ -138,3 +134,51 @@ handle_argv(int argc, char *argv[], char **env)
 		}
 	}
 }
+
+void
+__libc_start1(int argc, char *argv[], char *env[], void (*cleanup)(void),
+    int (*mainX)(int, char *[], char *[]))
+{
+	handle_argv(argc, argv, env);
+
+	if (&_DYNAMIC != NULL) {
+		atexit(cleanup);
+	} else {
+#ifndef CRT_IRELOC_SUPPRESS
+		INIT_IRELOCS;
+		process_irelocs();
+#endif
+		_init_tls();
+	}
+
+	handle_static_init(argc, argv, env);
+	exit(mainX(argc, argv, env));
+}
+
+/* XXXKIB _mcleanup and monstartup defs */
+extern void _mcleanup(void);
+extern void monstartup(void *, void *);
+
+void
+__libc_start1_gcrt(int argc, char *argv[], char *env[],
+    void (*cleanup)(void), int (*mainX)(int, char *[], char *[]),
+    int *eprolp, int *etextp)
+{
+	handle_argv(argc, argv, env);
+
+	if (&_DYNAMIC != NULL) {
+		atexit(cleanup);
+	} else {
+#ifndef CRT_IRELOC_SUPPRESS
+		INIT_IRELOCS;
+		process_irelocs();
+#endif
+		_init_tls();
+	}
+
+	atexit(_mcleanup);
+	monstartup(eprolp, etextp);
+
+	handle_static_init(argc, argv, env);
+	exit(mainX(argc, argv, env));
+}

lib/libc/csu/powerpc/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_SUPPRESS \
+		-DINIT_IRELOCS=""

lib/libc/csu/powerpc64/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_RELA \
+		-DINIT_IRELOCS="init_cpu_features(env)"

lib/libc/csu/powerpc64/reloc.c

@@ -23,6 +23,32 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
+static uint32_t cpu_features;
+static uint32_t cpu_features2;
+
+static void
+init_cpu_features(char **env)
+{
+	const Elf_Auxinfo *aux;
+
+	/* Find the auxiliary vector on the stack. */
+	while (*env++ != 0)	/* Skip over environment, and NULL terminator */
+		;
+	aux = (const Elf_Auxinfo *)env;
+
+	/* Digest the auxiliary vector. */
+	for (;  aux->a_type != AT_NULL; aux++) {
+		switch (aux->a_type) {
+		case AT_HWCAP:
+			cpu_features = (uint32_t)aux->a_un.a_val;
+			break;
+		case AT_HWCAP2:
+			cpu_features2 = (uint32_t)aux->a_un.a_val;
+			break;
+		}
+	}
+}
+
 static void
 crt1_handle_rela(const Elf_Rela *r)
 {

lib/libc/csu/riscv/Makefile.inc

@@ -0,0 +1,4 @@
+#
+
+CFLAGS+=	-DCRT_IRELOC_SUPPRESS \
+		-DINIT_IRELOCS=""

lib/libc/include/libc_private.h

@@ -255,6 +255,12 @@ enum {
 int _yp_check(char **);
 #endif
 
+void __libc_start1(int, char *[], char *[],
+    void (*)(void), int (*)(int, char *[], char *[])) __dead2;
+void __libc_start1_gcrt(int, char *[], char *[],
+    void (*)(void), int (*)(int, char *[], char *[]),
+    int *, int *) __dead2;
+
 /*
  * Initialise TLS for static programs
  */