Alexandre Oliva writes:

This patch adds code to uClibc to support a new ABI designed for the
FR-V architecture, that enables text segments of executables and
shared libraries to be shared by multiple processes on an OS such as
uClinux, that can run on FR-V processors without an MMU.

Patches for binutils and GCC have just been posted in the
corresponding mailing lists.  The binutils patch was approved,
but there's one additional patch pending review, that I posted
this week.  An updated GCC patch will be posted to
gcc-patches@gcc.gnu.org as soon as I complete testing (I used a
known-good compiler to test the uClibc patch below).

Since the existing dynamic loader code didn't support independent
relocation of segments, it required changes that were somewhat
extensive.  I've added a number of new machine-specific macros to try
to keep the platform and ABI-specific details outside the generic
code.  I hope this is not a problem.

1 files changed, 110 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/frv/crt0.S b/libc/sysdeps/linux/frv/crt0.S
new file mode 100644
index 000000000..8a425158f
--- /dev/null
+++ b/libc/sysdeps/linux/frv/crt0.S
@@ -0,0 +1,110 @@
+/* Copyright (C) 1991, 1992, 2003 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
+Library 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; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+
+/*  Based on ../i386/crt0.S and newlib's libgloss/frv/crt0.S  */
+
+/*
+    When we enter this piece of code, the program stack looks like this:
+        argc            argument counter (integer)
+        argv[0]         program name (pointer)
+        argv[1...N]     program args (pointers)
+        argv[argc-1]    end of args (integer)
+	NULL
+        env[0...N]      environment variables (pointers)
+        NULL
+
+    Also, GR16 holds a pointer to a memory map.  */
+
+#include <features.h>
+
+	.text
+	.global _start
+	.type	_start,%function
+#if defined L_crt0 || defined L_Scrt0 || ! defined __UCLIBC_CTOR_DTOR__
+	.type __uClibc_main,%function
+#else
+	.weak	_init
+	.weak	_fini
+	.type	__uClibc_start_main,%function
+#endif
+/* Stick in a dummy reference to main(), so that if an application
+ * is linking when the main() function is in a static library (.a)
+ * we can be sure that main() actually gets linked in */
+	.type	main,%function
+_start:
+	/* At program start-up, gr16 contains a pointer to a memory
+	   map, that we use to relocate addresses.  */
+	call	.Lcall
+.Lcall:
+	movsg	lr, gr4
+	sethi.p	#gprelhi(.Lcall), gr5
+	setlo	#gprello(.Lcall), gr5
+	sub.p	gr4, gr5, gr4
+	/* gr4 now holds the _gp address.  */
+	
+	mov	gr16, gr8
+	sethi.p #gprelhi(__ROFIXUP_LIST__), gr9
+	sethi	#gprelhi(__ROFIXUP_END__), gr10
+	setlo.p #gprello(__ROFIXUP_LIST__), gr9
+	setlo	#gprello(__ROFIXUP_END__), gr10
+	add.p	gr9, gr4, gr9
+	add	gr10, gr4, gr10
+	call	__self_reloc
+	mov.p	gr8, gr17
+	mov	gr8, gr15
+	/* gr17 now holds the self-relocated _GLOBAL_OFFSET_TABLE_
+	address, because the linker added its unrelocated address as
+	the last entry in the ROFIXUP list, and __self_reloc returns
+	the last entry, relocated.  */
+
+	/* Prepare arguments for uClibc main.  */
+	ld	@(sp, gr0), gr8
+	slli	gr8, #2, gr10
+	add	sp, gr10, gr10
+	addi.p	sp, #4, gr9
+	addi	gr10, #8, gr10
+
+	/* Set up an invalid (NULL return address, NULL frame pointer)
+	   callers stack frame so anybody unrolling the stack knows where
+	   to stop */
+	mov	gr0, fp
+	movgs	gr0, lr
+
+#if (defined L_crt1 || defined L_gcrt1 || defined L_Scrt1) && defined __UCLIBC_CTOR_DTOR__
+	/* Pass .init and .fini arguments to __uClibc_start_main().  */
+	sethi.p	#gotfuncdeschi(_init), gr11
+	sethi	#gotfuncdeschi(_fini), gr12
+	setlo.p	#gotfuncdesclo(_init), gr11
+	setlo	#gotfuncdesclo(_fini), gr12
+	ld.p	@(gr11, gr17), gr11
+	mov	gr17, gr15
+	ld.p	@(gr12, gr17), gr12
+	call	__uClibc_start_main
+#else
+	mov.p	gr17, gr15
+	call	__uClibc_main
+#endif	
+
+	/* Crash if somehow `exit' returns anyways.  */
+	jmpl	@(gr0,gr0)
+.size _start,.-_start
+
+#if defined L_gcrt1 && defined __UCLIBC_PROFILING__
+# include "./gmon-start.S"
+#endif