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

Hari Bathini hbathini at linux.vnet.ibm.com
Mon Apr 18 13:44:45 AEST 2016



On 04/15/2016 06:29 PM, Michael Ellerman wrote:
> 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")

Yeah. Thanks!

> cheers
>
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