On 12/21/21 20:27, John David Anglin wrote:
> On 2021-12-21 1:45 p.m., Rolf Eike Beer wrote:
>> Am Dienstag, 21. Dezember 2021, 19:33:16 CET schrieb John David Anglin:
>>> Fix mask used to select futex spinlock.
>>>
>>> The address bits used to select the futex spinlock need to match those used
>>> in the LWS code in syscall.S. The mask 0x3f8 only selects 7 bits. It
>>> should select 8 bits.
>> This change looks like this should become a helper macro or something like
>> that so the code will stay in sync. Can the mask be shared with the LWS code
>> with a constant while at it so it will also include that?
> I understand the point but it's rather convoluted. We would need a macro for the assembly
> code. Then the macro would need to be embedded in an asm for C. Then, there's the shift
> for the int* type in the C code.
>
> I am proposing to rewrite this code so the spinlock pointer is only computed once, but Helge
> wanted a change that could be easily back ported.
Right.
I think this is a small but important fix, which I can easily push back into older kernels.
See Dave's other patch ("[PATCH v1] parisc: Rewrite light-weight syscall and futex code").
There he rewrote the code anyway.
Helge
