Bad traps for unaligned access in STM instruction
Lluís Batlle i Rossell
viric at viric.name
Sat Sep 15 06:46:02 EDT 2012
Hello all,
I'm trying to diagnose a problem... on armv5tel, I have a userland software that runs an
STM instruction in those conditions:
r2 0xbeffeb95
r3 0x400000
r4 0x0
Instruction: stm r2, {r3, r4}
After stepping the instruction, I get:
(gdb) x/xg $r2
0xbeffeb95: 0xd800000000004000
While it should be: 0x0000000000400000
What can be going wrong? Linux 3.4.6 on armv5tel, gnueabi.
I know the kernel trap goes in, I told the kernel to report the unaligned
accesses, but I think it should fix them. From dmesg:
Alignment trap: mkfs.btrfs (28871) PC=0x00039ac0 Instr=0xe8820018
Address=0xbeffeb95 FSR 0x801
I'll start looking at the arm traps for unaligned accesses, but maybe someone
here can give a quick answer.
Regards,
Lluís.
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