On Mon, Dec 25, 2017 at 09:37:58PM +0300, Antony Pavlov wrote: > How to repropduce the unaligned store problem > > qemu-system-mips -nodefaults -M malta -m 256 \ > -nographic -serial stdio -monitor null \ > -bios barebox-flash-image \ > -net user -net nic,model=rtl8139 > > ... > > barebox:/ dhcp > > Ooops, address error on store! > > $ 0 : 00000000 00000000 01010600 697f2a2e > $ 4 : a0850000 00000000 0000001c a040c1b8 > $ 8 : 00000000 00000002 00000002 00000000 > $12 : 00000000 00000040 00000100 00000001 > $16 : a040bba0 a0850000 a0850000 a0850000 > $20 : 00000000 00000075 00000076 a040ba20 > $24 : 00000002 a080f210 > $28 : 00000000 a03ffce0 fffffffd a0833b8c > Hi : 000154f8 > Lo : 20000000 > epc : a0833b84 > ra : a0833b8c > Status: 00000002 > Cause : 80000414 > Config: 80008482 > > ### ERROR ### Please RESET the board ### > > The unaligned store instruction is located in the bootp_request() from net/dhcp.c: > > a0833b50 <bootp_request>: > .. > a0833b7c: 3c020101 lui v0,0x101 > a0833b80: 24420600 addiu v0,v0,1536 /* 0x1010600 -> v0 */ > a0833b84: 0c20024a jal a0800928 <get_time_ns> > a0833b88: ae02002a sw v0,42(s0) /* store 0x1010600 to addr s0 + 42 */ > > This assembler code is generated by mips-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 > from this: > > bp = (struct bootp *)payload; > bp->bp_op = OP_BOOTREQUEST; /* 0x01 */ > bp->bp_htype = HWT_ETHER; /* 0x01 */ > bp->bp_hlen = HWL_ETHER; /* 0x06 */ > bp->bp_hops = 0; > > Compiler replaces four 'store byte' instruction by one 'store 32-bit word' > instruction. Alas sometimes this leads to unaligned store situation. > > Making struct bootp __packed prevents this optimization and fixes the problem. > > Signed-off-by: Antony Pavlov <antonynpavlov@xxxxxxxxx> Applied to master, thanks Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
