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>
diff --git a/net/bootp.h b/net/bootp.h
index fcb0a64..567340e 100644
--- a/net/bootp.h
+++ b/net/bootp.h
@@ -49,7 +49,7 @@
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_hdr)