[PATCH] powerpc/32: Move entry_32 functions just after HEAD functions.

David Laight David.Laight at ACULAB.COM
Thu Apr 20 01:16:33 AEST 2017


From: Christophe Leroy
> By default, PPC8xx PINs an ITLB on the first 8M of memory in order
> to avoid any ITLB miss on kernel code.
> However, with some debug functions like DEBUG_PAGEALLOC and
> (soon to come) DEBUG_RODATA, the PINned TLB is invalidated soon
> after startup so ITLB missed start to happen also on the kernel code.
> 
> In order to avoid any ITLB miss in a critical section, we have to
> ensure that their is no page boundary crossed between the setup of
> a new value in SRR0/SRR1 and the associated RFI. This cannot be done
> easily if entry_32 functions sits in the middle of other .text
> functions. By placing entry_32 just after the .head section (as already
> done for entry_64 on PPC64), we can more easily ensure the issue
> doesn't happen.

Shouldn't this be done by putting all the functions that 'matter'
into a named section instead of relying on the order of the input files?
(Which is what I think this is doing.)

	David



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