svn commit: r295421 - head/sys/boot

[Andrew Turner]

Author: andrew
Date: Tue Feb  9 00:15:41 2016
New Revision: 295421
URL: https://svnweb.freebsd.org/changeset/base/295421

Log:
  Stop clang from generating movt/movw sequences. These don't get relocated
  so will access data from an unrelocated address. This is only needed for
  self relocating code on ARMv7, however this is true for both ubldr and
  loader.efi, the only two loaders we support on ARMv7.
  
  While here also force the fpu to be none as is done in libstand.
  
  Sponsored by:	ABT Systems Ltd

Modified:
  head/sys/boot/Makefile.inc

Modified: head/sys/boot/Makefile.inc
==============================================================================
--- head/sys/boot/Makefile.inc	Tue Feb  9 00:01:43 2016	(r295420)
+++ head/sys/boot/Makefile.inc	Tue Feb  9 00:15:41 2016	(r295421)
@@ -1,3 +1,11 @@
 # $FreeBSD$
 
 SSP_CFLAGS=
+
+.if ${MACHINE_CPUARCH} == "arm"
+# Do not generate movt/movw, because the relocation fixup for them does not
+# translate to the -Bsymbolic -pie format required by self_reloc() in loader(8).
+# Also, the fpu is not available in a standalone environment.
+CFLAGS.clang+=  -mllvm -arm-use-movt=0
+CFLAGS.clang+=  -mfpu=none
+.endif