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[Qemu-devel] Re: [sparc] Unassigned mem read access on writing?
From: |
Artyom Tarasenko |
Subject: |
[Qemu-devel] Re: [sparc] Unassigned mem read access on writing? |
Date: |
Sun, 7 Nov 2010 18:54:26 +0100 |
On Sun, Nov 7, 2010 at 3:56 PM, Blue Swirl <address@hidden> wrote:
> On Fri, Nov 5, 2010 at 5:48 PM, Artyom Tarasenko <address@hidden> wrote:
>> Trying to boot Solaris 2.1 I get the following error message:
>>
>> Unassigned mem read access of 1 byte to ffffffffffff0768 from f0014768
>> qemu: fatal: Trap 0x29 while interrupts disabled, Error state
>> pc: f0014768 npc: f001476c
>>
>> Looks like a read access to a non-mapped memory (the NF-bit is 0). But
>> where can it happen?
>>
>> The code:
>>
>> 0xf001475c: mov 0x200, %o4
>> => 0xf0014760: lda [ %o4 ] #ASI_N, %o3
>> 0xf0014764: sta %o2, [ %o4 ] #ASI_N
>> 0xf0014768: sta %g0, [ %o0 ] (3)
>> 0xf001476c: cmp %o2, %o3
>> 0xf0014770: bne 0xf001477c
>> End of assembler dump.
>> (gdb) stepi
>> 0xf0014764 in ?? ()
>> (gdb) info registers o2
>> o2 0x28a 650
>> (gdb) stepi
>> Remote connection closed
>> (gdb)
>>
>> Any ideas how to debug?
>
> All accesses are 32 bits wide. ASI_N is 4 and the other store access
> is to ASI 3 (MMU flush). I don't see how this is possible.
>
> Perhaps PC and NPC are not updated as they should. If you insert a
> breakpoint at the offending instruction, do you get the same error as
> above with the same PC/NPC value?
The crash is the same but it doesn't break. The option -singlestep
makes no difference either.
The log tail of ran with -d in_asm -singlestep:
IN:
0xf0014760: lda [ %o4 ] #ASI_M_MMUREGS, %o3
--------------
IN:
0xf0014764: sta %o2, [ %o4 ] #ASI_M_MMUREGS
qemu: fatal: Trap 0x29 while interrupts disabled, Error state
pc: f0014768 npc: f001476c
--
Regards,
Artyom Tarasenko
solaris/sparc under qemu blog: http://tyom.blogspot.com/