svn commit: r200894 - projects/mips/lib/csu/mips

[Warner Losh]

Author: imp
Date: Wed Dec 23 08:22:48 2009
New Revision: 200894
URL: http://svn.freebsd.org/changeset/base/200894

Log:
  Bring in support for n64 and n32 ABIs, at least at the base.
  
  o Rename __start to __start_mips and change the args a little
  o Create a new __start written in assembler that copes with the
    different ABIs and rewrites the args a little to make their passing
    more abi agnostic.
  o Add an alias _start for __start for the Cavium toolchain (in the
    cavium port, a custom ld script is used which references _start
    instead of the traditional mips __start).
  o call _init_tls() when we aren't being an a.out shared library (which
    is the only time _DYNAMIC is != NULL, I think).  We could likely
    retire support for a.out shared libraries entirely, but that will be
    in the future when I'm sure there's not some subtle reason to keep
    them around.
  
  # Note: the reason mips starts at __start instead of _start is purely
  # historical, but I didn't want to change it here and in the
  # toolchain.  The Cavium build process is kind of the odd duck here,
  # but it is trivial to support both, so why not...

Modified:
  projects/mips/lib/csu/mips/crt1.c

Modified: projects/mips/lib/csu/mips/crt1.c
==============================================================================
--- projects/mips/lib/csu/mips/crt1.c	Wed Dec 23 08:16:53 2009	(r200893)
+++ projects/mips/lib/csu/mips/crt1.c	Wed Dec 23 08:22:48 2009	(r200894)
@@ -1,6 +1,4 @@
 /*-
- * Copyright 1996-1998 John D. Polstra.
- * All rights reserved.
  * Copyright (c) 1995 Christopher G. Demetriou
  * All rights reserved.
  *
@@ -65,37 +63,94 @@ extern int etext;
 
 char **environ;
 const char *__progname = "";
+struct ps_strings *__ps_strings;
 
 void __gccmain(void) {}
 void __main(void) {}
 
+/*
+ * Historically, mips has used __start for the beginning address of programs.
+ * However, the Cavium toolchain (and maybe others) use _start.  Define both
+ * here.  The assembler code here tries to juggle the arguments such that they
+ * are right for all ABIs and then calls __start_mips which is what used to
+ * be just plain __start, and still is on other BSD ports.
+ */
+
 /* The entry function. */
+__asm("	.text			\n"
+"	.align	8		\n"
+"	.globl	_start		\n"
+"	_start:			\n"
+"	.globl	__start		\n"
+"	__start:		\n"
+#if defined(__mips_n32) || defined(__mips_n64)
+"	.cpsetup $25, $24, __start\n"
+#else
+"	.set noreorder		\n"
+"	.cpload $25		\n"
+"	.set reorder		\n"
+#endif
+"	/* Get cleanup routine and main object set by rtld */\n"
+"	/* Note that a2 is already set to ps_string by _rtld_start */\n"
+"	/* move	a3, a0        */\n"
+"	/* move	t0, a1        */\n"
+"	/* Get argc, argv from stack */	\n"
+"	/* lw	a0, 0(sp)     */\n"
+"	/* move	a1, sp        */\n"
+"	/* addu	a1, 4         */\n"
+"				\n"
+"	/* Stack should 8bytes aligned */\n"
+"	/* required by ABI to pass     */\n"
+"	/* 64-bits arguments           */\n"
+"	/* and	sp, ~8        */\n"
+"	/* subu	sp, sp, 20    */\n"
+"	/* sw	t0, 16(sp)    */\n"
+"				\n"
+"	move	$7, $4		/* atexit */\n"
+"	move	$8, $5		/* main_obj entry */\n"
+#if defined(__mips_n64)
+"	ld	$4, 0($29)	\n"
+"	move	$5, $29		\n"
+"	addu	$5, 8		\n"
+#else
+"	lw	$4, 0($29)	\n"
+"	move	$5, $29		\n"
+"	addu	$5, 4		\n"
+#endif
+"				\n"
+"	and	$29, 0xfffffff8	\n"
+"	subu	$29, $29, 24	/* args slot + cleanup + 4 bytes padding */ \n"
+"	sw	$8, 16($29)	\n"
+"\n"
+"	la	 $25, __start_mips  \n"
+"	nop	 \n"
+"	j	 $25\n");
+/* ARGSUSED */
+
 void
-__start(char **ap,
-	void (*cleanup)(void),			/* from shared loader */
-	struct Struct_Obj_Entry *obj,		/* from shared loader */
-	struct ps_strings *ps_strings)
+__start_mips(int argc, char **argv, struct ps_strings *ps_strings,
+    void (*cleanup)(void), struct Struct_Obj_Entry *obj __unused)
 {
-	int argc;
-	char **argv;
 	char **env;
+	const char *s;
 
-	argc = * (long *) ap;
-	argv = ap + 1;
-	env  = ap + 2 + argc;
+	env  = argv + argc + 1;
 	environ = env;
+
 	if(argc > 0 && argv[0] != NULL) {
-		const char *s;
 		__progname = argv[0];
 		for (s = __progname; *s != '\0'; s++)
 			if (*s == '/')
 				__progname = s + 1;
 	}
 
-#ifndef NOSHARED
+	__ps_strings = ps_strings;
+
 	if (&_DYNAMIC != NULL)
 		atexit(cleanup);
-#endif
+	else
+		_init_tls();
+
 #ifdef GCRT
 	atexit(_mcleanup);
 #endif