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, 118 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/frv/crtreloc.c b/libc/sysdeps/linux/frv/crtreloc.c
new file mode 100644
index 000000000..38af68c7b
--- /dev/null
+++ b/libc/sysdeps/linux/frv/crtreloc.c
@@ -0,0 +1,118 @@
+/* Copyright (C) 2003 Free Software Foundation, Inc.
+   written by Alexandre Oliva <aoliva@redhat.com>
+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.  */
+
+#define _GNU_SOURCE
+#include <link.h>
+
+#include <sys/types.h>
+
+#include <elf.h>
+#include <bits/elf-fdpic.h>
+
+/* This file is to be compiled into crt object files, to enable
+   executables to easily self-relocate.  */
+
+#define hidden __attribute__((__visibility__("hidden")))
+
+/* Compute the runtime address of pointer in the range [p,e), and then
+   map the pointer pointed by it.  */
+inline static void ***
+reloc_range_indirect (void ***p, void ***e,
+		      const struct elf32_fdpic_loadmap *map)
+{
+  while (p < e)
+    {
+      void *ptr = __reloc_pointer (*p, map);
+      if (ptr)
+	{
+	  void *pt;
+	  if ((long)ptr & 3)
+	    __builtin_memcpy(&pt, ptr, sizeof(pt));
+	  else
+	    pt = *(void**)ptr;
+	  pt = __reloc_pointer (pt, map);
+	  if ((long)ptr & 3)
+	    __builtin_memcpy(ptr, &pt, sizeof(pt));
+	  else
+	    *(void**)ptr = pt;
+	}
+      p++;
+    }
+  return p;
+}
+
+/* Call __reloc_range_indirect for the given range except for the last
+   entry, whose contents are only relocated.  It's expected to hold
+   the GOT value.  */
+void* hidden
+__self_reloc (const struct elf32_fdpic_loadmap *map,
+	      void ***p, void ***e)
+{
+  p = reloc_range_indirect (p, e-1, map);
+
+  if (p >= e)
+    return (void*)-1;
+  
+  return __reloc_pointer (*p, map);
+}
+
+#if 0
+/* These are other functions that might be useful, but that we don't
+   need.  */
+
+/* Remap pointers in [p,e).  */
+inline static void**
+reloc_range (void **p, void **e,
+	     const struct elf32_fdpic_loadmap *map)
+{
+  while (p < e)
+    {
+      *p = __reloc_pointer (*p, map);
+      p++;
+    }
+  return p;
+}
+
+/* Remap p, adjust e by the same offset, then map the pointers in the
+   range determined by them.  */
+void hidden
+__reloc_range (const struct elf32_fdpic_loadmap *map,
+	       void **p, void **e)
+{
+  void **old = p;
+
+  p = __reloc_pointer (p, map);
+  e += p - old;
+  reloc_range (p, e, map);
+}
+
+/* Remap p, adjust e by the same offset, then map pointers referenced
+   by the (unadjusted) pointers in the range.  Return the relocated
+   value of the last pointer in the range.  */
+void* hidden
+__reloc_range_indirect (const struct elf32_fdpic_loadmap *map,
+			void ***p, void ***e)
+{
+  void ***old = p;
+
+  p = __reloc_pointer (p, map);
+  e += p - old;
+  return reloc_range_indirect (p, e, map);
+}
+#endif