Re: [PATCH v1 2/6] powerpc/8xx: Always pin kernel text TLB

[Christophe Leroy]

Le 09/12/2020 à 11:43, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@xxxxxxxxxx> writes:
> > There is no big poing in not pinning kernel text anymore, as now
> > we can keep pinned TLB even with things like DEBUG_PAGEALLOC.
> >
> > Remove CONFIG_PIN_TLB_TEXT, making it always right.
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> > ---
> >   arch/powerpc/Kconfig               |  3 +--
> >   arch/powerpc/kernel/head_8xx.S     | 20 +++-----------------
> >   arch/powerpc/mm/nohash/8xx.c       |  3 +--
> >   arch/powerpc/platforms/8xx/Kconfig |  7 -------
> >   4 files changed, 5 insertions(+), 28 deletions(-)
> ...
> > diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
> > index 231ca95f9ffb..19a3eec1d8c5 100644
> > --- a/arch/powerpc/mm/nohash/8xx.c
> > +++ b/arch/powerpc/mm/nohash/8xx.c
> > @@ -186,8 +186,7 @@ void mmu_mark_initmem_nx(void)
> >   	mmu_mapin_ram_chunk(0, boundary, PAGE_KERNEL_TEXT, false);
> >   	mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false);
> >   
> > -	if (IS_ENABLED(CONFIG_PIN_TLB_TEXT))
> > -		mmu_pin_tlb(block_mapped_ram, false);
> > +	mmu_pin_tlb(block_mapped_ram, false);
> >   }
>
> This broke mpc885_ads_defconfig with:

:surprise:

How did I get it working ? Anyway, thanks for fixing it.

Christophe


>    ld: arch/powerpc/mm/nohash/8xx.o: in function `mmu_mark_initmem_nx':
>    /home/michael/linux/arch/powerpc/mm/nohash/8xx.c:189: undefined reference to `mmu_pin_tlb'
>    make[1]: *** [/home/michael/linux/Makefile:1164: vmlinux] Error 1
>    make: *** [Makefile:185: __sub-make] Error 2
>
> Fixed by:
>
> diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
> index 35707e86c5f3..52702f3db6df 100644
> --- a/arch/powerpc/kernel/head_8xx.S
> +++ b/arch/powerpc/kernel/head_8xx.S
> @@ -702,7 +702,6 @@ FixupDAR:/* Entry point for dcbx workaround. */
>   	mtspr	SPRN_DER, r8
>   	blr
>   
> -#ifdef CONFIG_PIN_TLB
>   _GLOBAL(mmu_pin_tlb)
>   	lis	r9, (1f - PAGE_OFFSET)@h
>   	ori	r9, r9, (1f - PAGE_OFFSET)@l
> @@ -802,7 +801,6 @@ _GLOBAL(mmu_pin_tlb)
>   	mtspr	SPRN_SRR1, r10
>   	mtspr	SPRN_SRR0, r11
>   	rfi
> -#endif /* CONFIG_PIN_TLB */
>   
>   /*
>    * We put a few things here that have to be page-aligned.
>
>
> cheers