Module Name:    src
Committed By:   martin
Date:           Sun Sep  1 14:03:02 UTC 2019

Modified Files:
        src/sys/arch/arm/conf [netbsd-9]: Makefile.arm
        src/sys/dev/usb [netbsd-9]: if_axe.c

Log Message:
Pull up following revision(s) (requested by rin in ticket #146):

        sys/arch/arm/conf/Makefile.arm: revision 1.50
        sys/dev/usb/if_axe.c: revision 1.120

PR kern/54486

Workaround for alignment faults on ARMv6+, at least occur with
axe(4) and athn(4) drivers.

For ARMv6+, unaligned access is enabled by default. However, it
cannot be used for non-cacheable memory, which is used as DMA
buffers. This results in alignment faults above. A real fix is
to use cacheable memory as DMA buffers. However, it breaks some
drivers, awge(4) and vchiq(4) at least.

Until we figure out problems and fix them, we choose a fail-safe
workaround here; forbid unaligned memory access for whole kernel.
Affects on performance is negligibly small as far as we can see.

XXX
pullup netbsd-9

 -

PR kern/54486
Revert workaround introduced in rev 1.94:
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/dev/usb/if_axe.c#rev1.94

This is a problem specific to ARMv6+, and addressed by
arch/arm/conf/Makefile.arm rev 1.50:
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/arch/arm/conf/Makefile.arm#rev1.50

XXX
pullup netbsd-9


To generate a diff of this commit:
cvs rdiff -u -r1.49 -r1.49.4.1 src/sys/arch/arm/conf/Makefile.arm
cvs rdiff -u -r1.102.2.1 -r1.102.2.2 src/sys/dev/usb/if_axe.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/arch/arm/conf/Makefile.arm
diff -u src/sys/arch/arm/conf/Makefile.arm:1.49 src/sys/arch/arm/conf/Makefile.arm:1.49.4.1
--- src/sys/arch/arm/conf/Makefile.arm:1.49	Sat Sep 22 12:24:01 2018
+++ src/sys/arch/arm/conf/Makefile.arm	Sun Sep  1 14:03:02 2019
@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile.arm,v 1.49 2018/09/22 12:24:01 rin Exp $
+#	$NetBSD: Makefile.arm,v 1.49.4.1 2019/09/01 14:03:02 martin Exp $
 
 # Makefile for NetBSD
 #
@@ -53,6 +53,26 @@ CPPFLAGS.cpufunc_asm_armv6.S+=	-mcpu=arm
 CPPFLAGS.cpufunc_asm_arm11.S+=	-mcpu=arm1136j-s
 CPPFLAGS.cpufunc_asm_xscale.S+=	-mcpu=xscale
 
+.if !empty(MACHINE_ARCH:Mearmv6*) || !empty(MACHINE_ARCH:Mearmv7*)
+# XXX
+#
+# Workaround for alignment faults on ARMv6+, at least occur with
+# axe(4) and athn(4) drivers.
+#
+# For ARMv6+, unaligned access is enabled by default. However, it
+# cannot be used for non-cacheable memory, which is used as DMA
+# buffers. This results in alignment faults above. A real fix is
+# to use cacheable memory as DMA buffers. However, it breaks some
+# drivers, awge(4) and vchiq(4) at least.
+#
+# Until we figure out problems and fix them, we choose a fail-safe
+# workaround here; forbid unaligned memory access for whole kernel.
+# Affects on performance is negligibly small as far as we can see.
+#
+# See PR kern/54486 for more details.
+CFLAGS+=	-mno-unaligned-access
+.endif
+
 ##
 ## (3) libkern and compat
 ##

Index: src/sys/dev/usb/if_axe.c
diff -u src/sys/dev/usb/if_axe.c:1.102.2.1 src/sys/dev/usb/if_axe.c:1.102.2.2
--- src/sys/dev/usb/if_axe.c:1.102.2.1	Sun Sep  1 13:00:36 2019
+++ src/sys/dev/usb/if_axe.c	Sun Sep  1 14:03:02 2019
@@ -1,4 +1,4 @@
-/*	$NetBSD: if_axe.c,v 1.102.2.1 2019/09/01 13:00:36 martin Exp $	*/
+/*	$NetBSD: if_axe.c,v 1.102.2.2 2019/09/01 14:03:02 martin Exp $	*/
 /*	$OpenBSD: if_axe.c,v 1.137 2016/04/13 11:03:37 mpi Exp $ */
 
 /*
@@ -87,7 +87,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_axe.c,v 1.102.2.1 2019/09/01 13:00:36 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_axe.c,v 1.102.2.2 2019/09/01 14:03:02 martin Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -1038,18 +1038,7 @@ axe_rx_loop(struct usbnet * un, struct u
 				break;
 			}
 
-#if !defined(__NO_STRICT_ALIGNMENT) && __GNUC_PREREQ__(6, 1)
-			/*
-			 * XXX hdr is 2-byte aligned in buf, not 4-byte.
-			 * For some architectures, __builtin_memcpy() of
-			 * GCC 6 attempts to copy sizeof(hdr) = 4 bytes
-			 * at onece, which results in alignment error.
-			 */
-			hdr.len = *(uint16_t *)buf;
-			hdr.ilen = *(uint16_t *)(buf + sizeof(uint16_t));
-#else
 			memcpy(&hdr, buf, sizeof(hdr));
-#endif
 
 			DPRINTFN(20, "total_len %#jx len %jx ilen %#jx",
 			    total_len,

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