ARM EABI support - changes to existing ARM code

[Daniel Jacobowitz <drow at false dot org>]

This patch updates the common ARM files for EABI support.  The changes are:
  - Old ARM ABI targets always use FPA (mixed-endian) byte ordering.  EABI
    targets always use VFP byte ordering for doubles, which is standard
    ieee754 layout.  Removing the arm-specific ieee754.h doesn't break FPA;
    it was a specialized version of the common header, which handles FPA
    but also handles VFP.
  - The stack needs to be aligned to eight bytes instead of just four,
    including in mmap2 and when shifting _dl_argv.
  - We need some markers around _start to indicate end-of-stack for the
    unwinder - ARM EABI does not use either SJLJ exceptions or DWARF-2
    exceptions.  It uses a table based format which seems to be not
    quite completely unlike DWARF-2.

Do these changes look OK?

-- 
Daniel Jacobowitz
CodeSourcery, LLC

2005-03-22  Daniel Jacobowitz  <dan@codesourcery.com>

	* sysdeps/arm/bits/endian.h (__FLOAT_WORD_ORDER): Handle VFP.
	* sysdeps/arm/gmp-mparam.h (IEEE_DOUBLE_BIG_ENDIAN,
	IEEE_DOUBLE_MIXED_ENDIAN): Handle big-endian and VFP.
	* sysdeps/arm/ieee754.h: Remove.

	* sysdeps/arm/dl-machine.h (_dl_start_user): Align the stack to eight
	bytes even when shifting arguments.
	* sysdeps/arm/dl-sysdep.h: New file.

	* sysdeps/arm/elf/start.S (_start): If not using SJLJ exceptions, include
	EABI unwind markers to terminate unwinding.

	* sysdeps/unix/sysv/linux/arm/mmap64.S: Handle big-endian byte ordering
	and EABI stack layout.

Index: glibc/sysdeps/arm/bits/endian.h
===================================================================
--- glibc.orig/sysdeps/arm/bits/endian.h	2005-03-22 10:26:27.092978200 -0500
+++ glibc/sysdeps/arm/bits/endian.h	2005-03-22 10:27:39.457490903 -0500
@@ -9,4 +9,9 @@
 #else
 #define __BYTE_ORDER __LITTLE_ENDIAN
 #endif
+
+#ifdef __VFP_FP__
+#define __FLOAT_WORD_ORDER __BYTE_ORDER
+#else
 #define __FLOAT_WORD_ORDER __BIG_ENDIAN
+#endif
Index: glibc/sysdeps/arm/dl-machine.h
===================================================================
--- glibc.orig/sysdeps/arm/dl-machine.h	2005-03-22 10:26:27.092978200 -0500
+++ glibc/sysdeps/arm/dl-machine.h	2005-03-22 10:27:39.457490903 -0500
@@ -156,22 +156,19 @@ _dl_start_user:\n\
 	add	sl, pc, sl\n\
 .L_GOT_GOT:\n\
 	ldr	r4, [sl, r4]\n\
-	@ get the original arg count\n\
-	ldr	r1, [sp]\n\
 	@ save the entry point in another register\n\
 	mov	r6, r0\n\
-	@ adjust the stack pointer to skip the extra args\n\
-	add	sp, sp, r4, lsl #2\n\
-	@ subtract _dl_skip_args from original arg count\n\
-	sub	r1, r1, r4\n\
+	@ get the original arg count\n\
+	ldr	r1, [sp]\n\
 	@ get the argv address\n\
 	add	r2, sp, #4\n\
-	@ store the new argc in the new stack location\n\
-	str	r1, [sp]\n\
+	@ Fix up the stack if necessary.\n\
+	cmp	r4, #0\n\
+	bne	.L_fixup_stack\n\
+.L_done_fixup:\n\
 	@ compute envp\n\
 	add	r3, r2, r1, lsl #2\n\
 	add	r3, r3, #4\n\
-\n\
 	@ now we call _dl_init\n\
 	ldr	r0, .L_LOADED\n\
 	ldr	r0, [sl, r0]\n\
@@ -182,12 +179,45 @@ _dl_start_user:\n\
 	add	r0, sl, r0\n\
 	@ jump to the user_s entry point\n\
 	" BX(r6) "\n\
+\n\
+	@ iWMMXt and EABI targets require the stack to be eight byte\n\
+	@ aligned - shuffle arguments etc.\n\
+.L_fixup_stack:\n\
+	@ subtract _dl_skip_args from original arg count\n\
+	sub	r1, r1, r4\n\
+	@ store the new argc in the new stack location\n\
+	str	r1, [sp]\n\
+	@ find the first unskipped argument\n\
+	mov	r3, r2\n\
+	add	r4, r2, r4, lsl #2\n\
+	@ shuffle argv down\n\
+1:	ldr	r5, [r4], #4\n\
+	str	r5, [r3], #4\n\
+	cmp	r5, #0\n\
+	bne	1b\n\
+	@ shuffle envp down\n\
+1:	ldr	r5, [r4], #4\n\
+	str	r5, [r3], #4\n\
+	cmp	r5, #0\n\
+	bne	1b\n\
+	@ shuffle auxv down\n\
+1:	ldmia	r4!, {r0, r5}\n\
+	stmia	r3!, {r0, r5}\n\
+	cmp	r0, #0\n\
+	bne	1b\n\
+	@ Update _dl_argv\n\
+	ldr	r3, .L_ARGV\n\
+	str	r2, [sl, r3]\n\
+	b	.L_done_fixup\n\
+\n\
 .L_GET_GOT:\n\
 	.word	_GLOBAL_OFFSET_TABLE_ - .L_GOT_GOT - 4\n\
 .L_SKIP_ARGS:\n\
 	.word	_dl_skip_args(GOTOFF)\n\
 .L_FINI_PROC:\n\
 	.word	_dl_fini(GOTOFF)\n\
+.L_ARGV:\n\
+	.word	_dl_argv(GOTOFF)\n\
 .L_LOADED:\n\
 	.word	_rtld_local(GOTOFF)\n\
 .previous\n\
Index: glibc/sysdeps/arm/dl-sysdep.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ glibc/sysdeps/arm/dl-sysdep.h	2005-03-22 10:27:39.458490675 -0500
@@ -0,0 +1,41 @@
+/* System-specific settings for dynamic linker code.  ARM version.
+   Copyright (C) 2004, 2005 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef _DL_SYSDEP_H
+#define _DL_SYSDEP_H   1
+
+/* This macro must be defined to either 0 or 1.
+
+   If 1, then an errno global variable hidden in ld.so will work right with
+   all the errno-using libc code compiled for ld.so, and there is never a
+   need to share the errno location with libc.  This is appropriate only if
+   all the libc functions that ld.so uses are called without PLT and always
+   get the versions linked into ld.so rather than the libc ones.  */
+
+#ifdef IS_IN_rtld
+# define RTLD_PRIVATE_ERRNO 1
+#else
+# define RTLD_PRIVATE_ERRNO 0
+#endif
+
+/* _dl_argv cannot be attribute_relro, because _dl_start_user
+   might write into it after _dl_start returns.  */
+#define DL_ARGV_NOT_RELRO 1
+
+#endif /* dl-sysdep.h */
Index: glibc/sysdeps/arm/elf/start.S
===================================================================
--- glibc.orig/sysdeps/arm/elf/start.S	2005-03-22 10:26:27.096977288 -0500
+++ glibc/sysdeps/arm/elf/start.S	2005-03-22 11:00:35.178522707 -0500
@@ -1,5 +1,6 @@
 /* Startup code for ARM & ELF
-   Copyright (C) 1995, 1996, 1997, 1998, 2001, 2002 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1996, 1997, 1998, 2001, 2002, 2005
+   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
@@ -62,6 +63,10 @@
 	.globl _start
 	.type _start,#function
 _start:
+#if !defined(__USING_SJLJ_EXCEPTIONS__)
+       /* Protect against unhandled exceptions.  */
+       .fnstart
+#endif
 	/* Fetch address of fini */
 	ldr ip, =__libc_csu_fini
 
@@ -93,6 +98,11 @@ _start:
 	/* should never get here....*/
 	bl abort
 
+#if !defined(__USING_SJLJ_EXCEPTIONS__)
+       .cantunwind
+       .fnend
+#endif
+
 /* Define a symbol for the first piece of initialized data.  */
 	.data
 	.globl __data_start
Index: glibc/sysdeps/arm/gmp-mparam.h
===================================================================
--- glibc.orig/sysdeps/arm/gmp-mparam.h	2005-03-22 10:26:27.092978200 -0500
+++ glibc/sysdeps/arm/gmp-mparam.h	2005-03-22 11:00:42.795683773 -0500
@@ -1,6 +1,6 @@
 /* gmp-mparam.h -- Compiler/machine parameter header file.
 
-Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
+Copyright (C) 1991, 1993, 1994, 1995, 2005 Free Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
 
@@ -26,5 +26,13 @@ MA 02111-1307, USA. */
 #define BITS_PER_SHORTINT 16
 #define BITS_PER_CHAR 8
 
-#define IEEE_DOUBLE_BIG_ENDIAN 0
-#define IEEE_DOUBLE_MIXED_ENDIAN 1
+#if defined(__ARMEB__)
+# define IEEE_DOUBLE_MIXED_ENDIAN 0
+# define IEEE_DOUBLE_BIG_ENDIAN 1
+#elif defined(__VFP_FP__)
+# define IEEE_DOUBLE_MIXED_ENDIAN 0
+# define IEEE_DOUBLE_BIG_ENDIAN 0
+#else
+# define IEEE_DOUBLE_BIG_ENDIAN 0
+# define IEEE_DOUBLE_MIXED_ENDIAN 1
+#endif
Index: glibc/sysdeps/arm/ieee754.h
===================================================================
--- glibc.orig/sysdeps/arm/ieee754.h	2005-03-22 10:26:27.092978200 -0500
+++ /dev/null	1970-01-01 00:00:00.000000000 +0000
@@ -1,115 +0,0 @@
-/* Copyright (C) 1992, 1995, 1996, 1998 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, write to the Free
-   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-   02111-1307 USA.  */
-
-#ifndef _IEEE754_H
-
-#define _IEEE754_H 1
-#include <features.h>
-
-#include <endian.h>
-
-__BEGIN_DECLS
-
-union ieee754_float
-  {
-    float f;
-
-    /* This is the IEEE 754 single-precision format.  */
-    struct
-      {
-	unsigned int mantissa:23;
-	unsigned int exponent:8;
-	unsigned int negative:1;
-      } ieee;
-
-    /* This format makes it easier to see if a NaN is a signalling NaN.  */
-    struct
-      {
-	unsigned int mantissa:22;
-	unsigned int quiet_nan:1;
-	unsigned int exponent:8;
-	unsigned int negative:1;
-      } ieee_nan;
-  };
-
-#define IEEE754_FLOAT_BIAS	0x7f /* Added to exponent.  */
-
-
-union ieee754_double
-  {
-    double d;
-
-    /* This is the IEEE 754 double-precision format.  */
-    struct
-      {
-	unsigned int mantissa0:20;
-	unsigned int exponent:11;
-	unsigned int negative:1;
-	unsigned int mantissa1:32;
-      } ieee;
-
-    /* This format makes it easier to see if a NaN is a signalling NaN.  */
-    struct
-      {
-	unsigned int mantissa0:19;
-	unsigned int quiet_nan:1;
-	unsigned int exponent:11;
-	unsigned int negative:1;
-	unsigned int mantissa1:32;
-      } ieee_nan;
-  };
-
-#define IEEE754_DOUBLE_BIAS	0x3ff /* Added to exponent.  */
-
-
-/* The following two structures are correct for `new' floating point systems but
-   wrong for the old FPPC.  The only solution seems to be to avoid their use on
-   old hardware.  */
-
-union ieee854_long_double
-  {
-    long double d;
-
-    /* This is the IEEE 854 double-extended-precision format.  */
-    struct
-      {
-	unsigned int exponent:15;
-	unsigned int empty:16;
-	unsigned int negative:1;
-	unsigned int mantissa1:32;
-	unsigned int mantissa0:32;
-      } ieee;
-
-    /* This is for NaNs in the IEEE 854 double-extended-precision format.  */
-    struct
-      {
-	unsigned int exponent:15;
-	unsigned int empty:16;
-	unsigned int negative:1;
-	unsigned int mantissa1:32;
-	unsigned int mantissa0:30;
-	unsigned int quiet_nan:1;
-	unsigned int one:1;
-      } ieee_nan;
-  };
-
-#define IEEE854_LONG_DOUBLE_BIAS 0x3fff
-
-__END_DECLS
-
-#endif /* ieee754.h */
Index: glibc/sysdeps/unix/sysv/linux/arm/mmap64.S
===================================================================
--- glibc.orig/sysdeps/unix/sysv/linux/arm/mmap64.S	2005-03-22 10:26:27.097977060 -0500
+++ glibc/sysdeps/unix/sysv/linux/arm/mmap64.S	2005-03-22 11:00:53.051209928 -0500
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2000, 2003, 2005 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
@@ -23,13 +23,28 @@
 
 #include "kernel-features.h"
 
+#ifdef __ARM_EABI__
+# define INITIAL_OFFSET 8
+#else
+# define INITIAL_OFFSET 4
+#endif
+
+#ifdef __ARMEB__
+# define LOW_OFFSET      INITIAL_OFFSET + 4
+/* The initial + 4 is for the stack postdecrement.  */
+# define HIGH_OFFSET 4 + INITIAL_OFFSET + 0
+#else
+# define LOW_OFFSET      INITIAL_OFFSET + 0
+# define HIGH_OFFSET 4 + INITIAL_OFFSET + 4
+#endif
+
 	/* The mmap2 system call takes six arguments, all in registers.  */
 	.text
 ENTRY (__mmap64)
 #ifdef __NR_mmap2
-	ldr	ip, [sp, $4]		@ offset low part
+	ldr	ip, [sp, $LOW_OFFSET]	@ offset low part
 	str	r5, [sp, #-4]!
-	ldr	r5, [sp, $12]		@ offset high part
+	ldr	r5, [sp, $HIGH_OFFSET]	@ offset high part
 	str	r4, [sp, #-4]!
 	movs	r4, ip, lsl $20		@ check that offset is page-aligned
 	mov	ip, ip, lsr $12