From: zbb <zbb@FreeBSD.org>
Date: Fri, 30 Oct 2015 12:21:37 +0000 (+0000)
Subject: Workaround KGDB issues on ARM by ignoring ARM EABI version higher than 5
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=dbf29557d917055e8603643594313199f544af88;p=people%2Fjulieng%2Ffreebsd.git

Workaround KGDB issues on ARM by ignoring ARM EABI version higher than 5

To make KGDB working, it needs to understand kernel ELF image.
By default it is compiled using EABI_5, which is not supported
on the gdb-6. As a workaround, treat these images as EABI_2 because
they share a lot of things in common.

This workaround does not guarantee ALL funtionalities
to work.

Submitted by:  Wojciech Macek <wma@semihalf.com>
Reviewed by:   jhb
Obtained from: Semihalf
Sponsored by:  Juniper Networks Inc.
Differential Revision: https://reviews.freebsd.org/D4012
---

diff --git a/contrib/gdb/gdb/arm-tdep.c b/contrib/gdb/gdb/arm-tdep.c
index 128219f6ee46..cec90617439f 100644
--- a/contrib/gdb/gdb/arm-tdep.c
+++ b/contrib/gdb/gdb/arm-tdep.c
@@ -2580,6 +2580,21 @@ arm_elf_osabi_sniffer (bfd *abfd)
 	      osabi = GDB_OSABI_ARM_EABI_V2;
 	      break;
 
+	    case EF_ARM_EABI_VER3:
+	    case EF_ARM_EABI_VER4:
+	    case EF_ARM_EABI_VER5:
+	      /*
+	       * GDB does not support these EABI versions. Fallback
+	       * to the highest known to make the KGDB working with
+	       * kernel ELF image.
+	       */
+	      osabi = GDB_OSABI_ARM_EABI_V2;
+	      printf ("\n%s:%d "
+	              "arm_elf_osabi_sniffer: Unsupported ARM EABI "
+	              "version 0x%x, falling back to 0x%x\n",
+	              __FILE__, __LINE__, eflags, EF_ARM_EABI_VER2);
+	      break;
+
 	    case EF_ARM_EABI_UNKNOWN:
 	      /* Assume GNU tools.  */
 	      osabi = GDB_OSABI_ARM_APCS;