svn commit: r261137 - head/sys/arm/include

[Andrew Turner]

Author: andrew
Date: Fri Jan 24 20:51:56 2014
New Revision: 261137
URL: http://svnweb.freebsd.org/changeset/base/261137

Log:
  Correct the alignment of sp through functions that use UNWINDSVCFRAME. We
  were incorrectly adding the trap frame padding to the stack pointer after
  reading it's value and unaligning it.

Modified:
  head/sys/arm/include/asmacros.h

Modified: head/sys/arm/include/asmacros.h
==============================================================================
--- head/sys/arm/include/asmacros.h	Fri Jan 24 20:26:00 2014	(r261136)
+++ head/sys/arm/include/asmacros.h	Fri Jan 24 20:51:56 2014	(r261137)
@@ -216,8 +216,13 @@
 	ldmia	sp, {sp, lr, pc}^	/* Restore lr and exit */
 #endif
 #if defined(__ARM_EABI__)
+/*
+ * Unwind hints so we can unwind past functions that use
+ * PULLFRAMEFROMSVCANDEXIT. They are run in reverse order.
+ * As the last thing we do is restore the stack pointer
+ * we can ignore the padding at the end of struct trapframe.
+ */
 #define	UNWINDSVCFRAME							   \
-	.pad #(4);			/* Skip stack alignment */	   \
 	.save {r13-r15};		/* Restore sp, lr, pc */	   \
 	.pad #(2*4);			/* Skip user sp and lr */	   \
 	.save {r0-r12};			/* Restore r0-r12 */		   \