uboot-fritz4040: fix crash caused by interaction with gcc 7.1+

David Bauer reported a u-boot crash (data abort) at a odd
place (byteswap) when he ran ping/tftp on his 7530.

|(FRITZ7530) # ping 192.168.1.70
|eth0 PHY0 up Speed :1000 Full duplex
|eth0 PHY1 Down Speed :10 Half duplex
|eth0 PHY2 Down Speed :10 Half duplex
|eth0 PHY3 Down Speed :10 Half duplex
|eth0 PHY4 Down Speed :10 Half duplex
|Using eth0 device
|data abort
|pc : [<84234774>]      lr : [<842351a4>]
|sp : 8412fdb0  ip : 0000009b     fp : 00000000
|r10: 00000000  r9 : 00000001     r8 : 8412ff68
|r7 : 00000000  r6 : 0000002a     r5 : 84244e90  r4 : 8425e28e
|r3 : 84244e90  r2 : 14000045     r1 : 8412fdb0  r0 : 8425e28e
|Flags: nZCv  IRQs off  FIQs off  Mode SVC_32
|Resetting CPU ...
|
|resetting ...

This issue is caused by switch from gcc 5.5 to 7.1+ as explained
in the upstream patch:

|From a768e513b07b5999a8e7d7740ac8d9da04ee7e51 Mon Sep 17 00:00:00 2001
|From: Denis Pynkin <denis.pynkin@collabora.com>
|Date: Fri, 21 Jul 2017 19:28:42 +0300
|Subject: [PATCH] net: Use packed structures for networking
|
|PXE boot is broken with GCC 7.1 due option '-fstore-merging' enabled
|by default for '-O2':
|
|BOOTP broadcast 1
|data abort
|pc : [<8ff8bb30>]          lr : [<00004f1f>]
|reloc pc : [<17832b30>]    lr : [<878abf1f>]
|sp : 8f558bc0  ip : 00000000     fp : 8ffef5a4
|r10: 8ffed248  r9 : 8f558ee0     r8 : 8ffef594
|r7 : 0000000e  r6 : 8ffed700     r5 : 00000000  r4 : 8ffed74e
|r3 : 00060101  r2 : 8ffed230     r1 : 8ffed706  r0 : 00000ddd
|Flags: nzcv  IRQs off  FIQs off  Mode S
|
|Core reason is usage of structures for network headers without packed
|attribute.

This patch just backports the upstream change to the
uboot-fritz4040 package.

Reported-by: David Bauer <mail@david-bauer.net>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

1 files changed, 137 insertions, 0 deletions

diff --git a/package/boot/uboot-fritz4040/patches/120-net-Use-packed-structures-for-networking.patch b/package/boot/uboot-fritz4040/patches/120-net-Use-packed-structures-for-networking.patch
new file mode 100644
index 0000000000..8a7b0bb04f
--- /dev/null
+++ b/package/boot/uboot-fritz4040/patches/120-net-Use-packed-structures-for-networking.patch
@@ -0,0 +1,137 @@
+From: Denis Pynkin <denis.pynkin@collabora.com>
+Date: Fri, 21 Jul 2017 19:28:42 +0300
+Subject: [PATCH] net: Use packed structures for networking
+
+PXE boot is broken with GCC 7.1 due option '-fstore-merging' enabled
+by default for '-O2':
+
+BOOTP broadcast 1
+data abort
+pc : [<8ff8bb30>]          lr : [<00004f1f>]
+reloc pc : [<17832b30>]    lr : [<878abf1f>]
+sp : 8f558bc0  ip : 00000000     fp : 8ffef5a4
+r10: 8ffed248  r9 : 8f558ee0     r8 : 8ffef594
+r7 : 0000000e  r6 : 8ffed700     r5 : 00000000  r4 : 8ffed74e
+r3 : 00060101  r2 : 8ffed230     r1 : 8ffed706  r0 : 00000ddd
+Flags: nzcv  IRQs off  FIQs off  Mode SVC_32
+Resetting CPU ...
+
+Core reason is usage of structures for network headers without packed
+attribute.
+
+Reviewed-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
+Signed-off-by: Denis Pynkin <denis.pynkin@collabora.com>
+Acked-by: Joe Hershberger <joe.hershberger@ni.com>
+Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
+[backported from u-boot main]
+---
+
+--- a/include/net.h
++++ b/include/net.h
+@@ -182,7 +182,7 @@ struct ethernet_hdr {
+ 	uchar		et_dest[6];	/* Destination node		*/
+ 	uchar		et_src[6];	/* Source node			*/
+ 	ushort		et_protlen;	/* Protocol or length		*/
+-};
++} __attribute__((packed));
+ 
+ /* Ethernet header size */
+ #define ETHER_HDR_SIZE	(sizeof(struct ethernet_hdr))
+@@ -198,7 +198,7 @@ struct e802_hdr {
+ 	uchar		et_snap2;
+ 	uchar		et_snap3;
+ 	ushort		et_prot;	/* 802 protocol			*/
+-};
++} __attribute__((packed));
+ 
+ /* 802 + SNAP + ethernet header size */
+ #define E802_HDR_SIZE	(sizeof(struct e802_hdr))
+@@ -212,7 +212,7 @@ struct vlan_ethernet_hdr {
+ 	ushort		vet_vlan_type;	/* PROT_VLAN			*/
+ 	ushort		vet_tag;	/* TAG of VLAN			*/
+ 	ushort		vet_type;	/* protocol type		*/
+-};
++} __attribute__((packed));
+ 
+ /* VLAN Ethernet header size */
+ #define VLAN_ETHER_HDR_SIZE	(sizeof(struct vlan_ethernet_hdr))
+@@ -239,7 +239,7 @@ struct ip_hdr {
+ 	ushort		ip_sum;		/* checksum			*/
+ 	IPaddr_t	ip_src;		/* Source IP address		*/
+ 	IPaddr_t	ip_dst;		/* Destination IP address	*/
+-};
++} __attribute__((packed));
+ 
+ #define IP_OFFS		0x1fff /* ip offset *= 8 */
+ #define IP_FLAGS	0xe000 /* first 3 bits */
+@@ -267,7 +267,7 @@ struct ip_udp_hdr {
+ 	ushort		udp_dst;	/* UDP destination port		*/
+ 	ushort		udp_len;	/* Length of UDP packet		*/
+ 	ushort		udp_xsum;	/* Checksum			*/
+-};
++} __attribute__((packed));
+ 
+ #define IP_UDP_HDR_SIZE		(sizeof(struct ip_udp_hdr))
+ #define UDP_HDR_SIZE		(IP_UDP_HDR_SIZE - IP_HDR_SIZE)
+@@ -306,7 +306,7 @@ struct arp_hdr {
+ 	uchar		ar_tha[];	/* Target hardware address	*/
+ 	uchar		ar_tpa[];	/* Target protocol address	*/
+ #endif /* 0 */
+-};
++} __attribute__((packed));
+ 
+ #define ARP_HDR_SIZE	(8+20)		/* Size assuming ethernet	*/
+ 
+@@ -341,7 +341,7 @@ struct icmp_hdr {
+ 		} frag;
+ 		uchar data[0];
+ 	} un;
+-};
++} __attribute__((packed));
+ 
+ #define ICMP_HDR_SIZE		(sizeof(struct icmp_hdr))
+ #define IP_ICMP_HDR_SIZE	(IP_HDR_SIZE + ICMP_HDR_SIZE)
+--- a/net/bootp.h
++++ b/net/bootp.h
+@@ -49,7 +49,7 @@ struct Bootp_t {
+ 	char		bp_sname[64];	/* Server host name		*/
+ 	char		bp_file[128];	/* Boot file name		*/
+ 	char		bp_vend[OPT_FIELD_SIZE]; /* Vendor information	*/
+-};
++} __attribute__((packed));
+ 
+ #define BOOTP_HDR_SIZE	sizeof(struct Bootp_t)
+ 
+--- a/net/dns.h
++++ b/net/dns.h
+@@ -32,7 +32,7 @@ struct header {
+ 	uint16_t	nauth;		/* Authority PRs */
+ 	uint16_t	nother;		/* Other PRs */
+ 	unsigned char	data[1];	/* Data, variable length */
+-};
++} __attribute__((packed));
+ 
+ extern void DnsStart(void);		/* Begin DNS */
+ 
+--- a/net/nfs.h
++++ b/net/nfs.h
+@@ -71,7 +71,7 @@ struct rpc_t {
+ 			uint32_t data[19];
+ 		} reply;
+ 	} u;
+-};
++} __attribute__((packed));
+ extern void NfsStart(void);	/* Begin NFS */
+ 
+ 
+--- a/net/sntp.h
++++ b/net/sntp.h
+@@ -54,7 +54,7 @@ struct sntp_pkt_t {
+ 	unsigned long long originate_timestamp;
+ 	unsigned long long receive_timestamp;
+ 	unsigned long long transmit_timestamp;
+-};
++} __attribute__((packed));
+ 
+ extern void SntpStart(void);	/* Begin SNTP */
+