Do not define __NO_STRICT_ALIGNMENT for armv6. While the requirements

are no longer natural-alignment strict, there are still some restrictions.

FreeBSD network code assumes data is naturally-aligned or is running
on a platform with no restrictions; pointers are not annotated to
indicate the data pointed to may be packed or unaligned.  The clang
optimizer can sometimes combine the load or store of a pair of adjacent
32-bit values into a single doubleword load/store, and that operation
requires at least 4-byte alignment.  __NO_STRICT_ALIGNMENT can lead
to tcp headers being only 2-byte aligned.

Note that alignment faults remain disabled on armv6, this change reverts
only the defining of the symbol which leads to some overly-agressive code
shortcuts when building common/shared drivers and network code for arm.

Approved by:	re(kib)

This commit is contained in:

Ian Lepore

2016-06-13 16:48:27 +00:00

parent 47c5f8f2fe

commit e2a03c1fe5

1 changed files with 0 additions and 4 deletions

									
										sys/arm/include/_types.h
									
		-4
	
												View File
												
				@@ -43,10 +43,6 @@

				#error this file needs sys/cdefs.h as a prerequisite

				#endif

				#if __ARM_ARCH >= 6

				#define __NO_STRICT_ALIGNMENT

				#endif

				/*

				 * Basic types upon which most other types are built.

				 */