Re: [PATCH] target/hppa: mask upper iaoq bits when returning to narrow mode

[Sven Schnelle]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 4/1/24 10:39, Sven Schnelle wrote:
>> Richard Henderson <richard.henderson@linaro.org> writes:
>>>> For unknown reasons, Java 1.5 on 64-bit HP-UX 11.11 does signed
>>>> computation of the new IAOQ value in the signal handler. In the
>>>> current code these bits are not masked when returning to narrow
>>>> mode, causing java to crash.
>>>> Signed-off-by: Sven Schnelle <svens@stackframe.org>
>> INT   3530: instruction tlb miss fault @ 0000000000000000:ffffffffc0000007 
>> for 0000000000000000:40000000c0000004
>> INT   3531: external interrupt @ 0000000000000000:ffffffffc0000007 for 
>> 0000000000000000:40000000c0000004
>> INT   3532: instruction tlb miss fault @ 0000000000000000:ffffffffc0000007 
>> for 0000000000000000:40000000c0000004
>> INT   3533: external interrupt @ 0000000000000000:ffffffffc0000007 for 
>> 0000000000000000:40000000c0000004
>> So the PSW indicates narrow mode, but IAOQ seems to contain all the
>> ffff... bits.
>
> I believe that the IAOQ *should* contain all of the bits.  The bits
> should only be discarded when we form the GVA -- exactly like "ldb
> 0(r2)", where r2 contains all of the offset bits.  In particular, I
> believe that "b,l .+8,r2" should copy all of those bits to r2 from
> IAOQ_Back+4 and the fact that mainline crops those bits is a bug.
>
>
>> Also interesting is that the second TLB miss (INT 3530)
>> misses the Space ID.
>
> That is a bit curious, yes.
>
>> Any thoughts? Otherwise i need to investigate and make a wrong patch
>> again :-)
>> The only patch i have on top which touches target/hppa is the space
>> id
>> hashing mask patch:
>
> Ok.  I do have an hppa 11.11 iso -- for clarity, what is your command-line?

I'm using:

./build/qemu-system-hppa -M C3700 -m 1024 -cdrom 
/home/svens/parisc/hpux/11.11/HP-UX 11.11 (2004-12) - TCOE - Core OS, Install 
and Recovery - DVD.iso -bios 
/home/svens/seabios-hppa/out-64/hppa-firmware64.img -nographic -hda 
/home/svens/parisc/hpux1111.img -boot d


The qemu i'm using is: https://github.com/svenschnelle/qemu/tree/devel

You also need a special seabios-hppa version, because a special console
driver is needed:

https://github.com/hdeller/seabios-hppa/tree/devel