[Patch v2 2/2] Enable ILP32 mode in gdb on aarch64

[Steve Ellcey <sellcey at caviumnetworks dot com>]

Here is the second of two gdb patches to support aarch64 ILP32 mode.
This one just has the bfd changes.  I sent the cpu-aarch64.c and
elfnn-aarch64.c parts before but I had to add a change to elfxx-
aarch64.c to fix gdb support in ILP32 mode.

Steve Ellcey
sellcey@cavium.com


2017-03-06  Andrew Pinski  <apinski@cavium.com>
	    Steve Ellcey  <sellcey@cavium.com>

	* cpu-aarch64.c (compatible):
	Don't reject different ILP32/LP64 ABI's here.
	* elfnn-aarch64.c (elfNN_aarch64_merge_private_bfd_data):
	Add an error message on why endianess is rejected.
	Reject different ILP32/LP64 ABI settings.
	* elfxx-aarch64.c (_bfd_aarch64_elf_grok_prstatus): Handle
	size and offset of ILP32 executables.
	(_bfd_aarch64_elf_grok_psinfo):  Ditto.

diff --git a/bfd/cpu-aarch64.c b/bfd/cpu-aarch64.c
index 7cb81f3..63fba48 100644
--- a/bfd/cpu-aarch64.c
+++ b/bfd/cpu-aarch64.c
@@ -25,7 +25,8 @@
 
 /* This routine is provided two arch_infos and works out which Aarch64
    machine which would be compatible with both and returns a pointer
-   to its info structure.  */
+   to its info structure.  ABI (ilp32 vs. lp64) and endianness compatibility
+   are checked in elfNN_aarch64_merge_private_bfd_data.  */
 
 static const bfd_arch_info_type *
 compatible (const bfd_arch_info_type * a, const bfd_arch_info_type * b)
@@ -38,10 +39,6 @@ compatible (const bfd_arch_info_type * a, const bfd_arch_info_type * b)
   if (a->mach == b->mach)
     return a;
 
-  /* Don't allow mixing ilp32 with lp64.  */
-  if ((a->mach & bfd_mach_aarch64_ilp32) != (b->mach & bfd_mach_aarch64_ilp32))
-    return NULL;
-
   /* Otherwise if either a or b is the 'default' machine
      then it can be polymorphed into the other.  */
   if (a->the_default)
diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index c86a3e1..9b82f4b 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -6597,11 +6597,26 @@ elfNN_aarch64_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
 
   /* Check if we have the same endianess.  */
   if (!_bfd_generic_verify_endian_match (ibfd, info))
-    return FALSE;
+    {
+      (*_bfd_error_handler)
+	(_("%B: endianness incompatible with that of the selected emulation"),
+	   ibfd);
+      return FALSE;
+    }
 
   if (!is_aarch64_elf (ibfd) || !is_aarch64_elf (obfd))
     return TRUE;
 
+  /* Don't allow mixing ilp32 with lp64.  */
+  if ((bfd_get_arch_info (ibfd)->mach & bfd_mach_aarch64_ilp32)
+      != (bfd_get_arch_info (obfd)->mach & bfd_mach_aarch64_ilp32))
+    {
+      (*_bfd_error_handler)
+	(_("%B: ABI is incompatible with that of the selected emulation: \"%s\" != \"%s\""),
+	 ibfd, bfd_get_target (ibfd), bfd_get_target (obfd));
+      return FALSE;
+    }
+
   /* The input BFD must have had its flags initialised.  */
   /* The following seems bogus to me -- The flags are initialized in
      the assembler but I don't think an elf_flags_init field is
diff --git a/bfd/elfxx-aarch64.c b/bfd/elfxx-aarch64.c
index 1c5c72a..fb62061 100644
--- a/bfd/elfxx-aarch64.c
+++ b/bfd/elfxx-aarch64.c
@@ -559,14 +559,25 @@ _bfd_aarch64_elf_grok_prstatus (bfd *abfd, Elf_Internal_Note *note)
       default:
 	return FALSE;
 
-      case 392:		/* sizeof(struct elf_prstatus) on Linux/arm64.  */
+      case 352:	/* sizeof(struct elf_prstatus) on Linux/aarch64 ilp32.  */
 	/* pr_cursig */
-	elf_tdata (abfd)->core->signal
-	  = bfd_get_16 (abfd, note->descdata + 12);
+	elf_tdata (abfd)->core->signal = bfd_get_16 (abfd, note->descdata + 12);
 
 	/* pr_pid */
-	elf_tdata (abfd)->core->lwpid
-	  = bfd_get_32 (abfd, note->descdata + 32);
+	elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 32);
+
+	/* pr_reg */
+	offset = 72;
+	size = 272;
+
+	break;
+
+      case 392:	/* sizeof(struct elf_prstatus) on Linux/aarch64.  */
+	/* pr_cursig */
+	elf_tdata (abfd)->core->signal = bfd_get_16 (abfd, note->descdata + 12);
+
+	/* pr_pid */
+	elf_tdata (abfd)->core->lwpid = bfd_get_32 (abfd, note->descdata + 32);
 
 	/* pr_reg */
 	offset = 112;
@@ -588,12 +599,21 @@ _bfd_aarch64_elf_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
     default:
       return FALSE;
 
-    case 136:        /* This is sizeof(struct elf_prpsinfo) on Linux/aarch64.  */
+    case 124:         /* sizeof(struct elf_prpsinfo) on Linux/aarch64 ilp32.  */
+      elf_tdata (abfd)->core->pid = bfd_get_32 (abfd, note->descdata + 12);
+      elf_tdata (abfd)->core->program
+	= _bfd_elfcore_strndup (abfd, note->descdata + 28, 16);
+      elf_tdata (abfd)->core->command
+	= _bfd_elfcore_strndup (abfd, note->descdata + 44, 80);
+      break;
+
+    case 136:        /* sizeof(struct elf_prpsinfo) on Linux/aarch64.  */
       elf_tdata (abfd)->core->pid = bfd_get_32 (abfd, note->descdata + 24);
       elf_tdata (abfd)->core->program
 	= _bfd_elfcore_strndup (abfd, note->descdata + 40, 16);
       elf_tdata (abfd)->core->command
 	= _bfd_elfcore_strndup (abfd, note->descdata + 56, 80);
+      break;
     }
 
   /* Note that for some reason, a spurious space is tacked