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>

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 (file)
index 0000000..8a7b0bb
--- /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 */
+