[v4, 2/3] ppc64/book3s: make some room for common interrupt vector code

Michael Ellerman mpe at ellerman.id.au
Fri Apr 15 22:59:57 AEST 2016


On Fri, 2016-04-15 at 21:06 +1000, Michael Ellerman wrote:
> Hi Hari,
>
> Thanks for persisting with this.
>
> On Thu, 2016-07-04 at 21:58:50 UTC, Hari Bathini wrote:

> > With the previous patch, we choke out whatever little space is left
> > below 0x7000 (FWNMI hard block) while there is a hole of ~1400 bytes
> > below __end_interrupts marker when CONFIG_CBE_RAS is disabled.
> > Considering CONFIG_CBE_RAS is not enabled by default for BOOK3S, this
> > is not a desirable scenario especially when we have to worry about
> > each additional instruction that goes below 0x7000.
> >
> > Memory region from 0x1800 to 0x4000 is dedicated for common interrupt
> > vector code. Also, we never hit an interrupt below 0x300 when IR=DR=1
> > implying memory region between 0x4000 to 0x4300 can also be used for
> > common interrupt vector code. So, we can effectively use memory region
> > between 0x1800 to 0x4300 for common interrupt vector code.
>
> On Power9 the system-call-vectored instruction will use the region at 0x3000, so
> moving code into that space is not a good long term plan.
>
> I'll take your v2 and put it in next next week.

I'll add this fixes line, which I think is correct:

Fixes: c1fb6816fb1b ("powerpc: Add relocation on exception vector handlers")

cheers



More information about the Linuxppc-dev mailing list