Michael, ping.
Le 07/12/2021 à 07:10, Christophe Leroy a écrit :
> Allthough kernel text is always mapped with BATs, we still have
> inittext mapped with pages, so TLB miss handling is required
> when CONFIG_DEBUG_PAGEALLOC or CONFIG_KFENCE is set.
>
> The final solution should be to set a BAT that also maps inittext
> but that BAT then needs to be cleared at end of init, and it will
> require more changes to be able to do it properly.
>
> As DEBUG_PAGEALLOC or KFENCE are debugging, performance is not a big
> deal so let's fix it simply for now to enable easy stable application.
>
> Reported-by: Maxime Bizon <mbi...@freebox.fr>
> Fixes: 035b19a15a98 ("powerpc/32s: Always map kernel text and rodata with
> BATs")
> Cc: sta...@vger.kernel.org
> Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
> ---
> arch/powerpc/kernel/head_book3s_32.S | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/head_book3s_32.S
> b/arch/powerpc/kernel/head_book3s_32.S
> index 68e5c0a7e99d..2e2a8211b17b 100644
> --- a/arch/powerpc/kernel/head_book3s_32.S
> +++ b/arch/powerpc/kernel/head_book3s_32.S
> @@ -421,14 +421,14 @@ InstructionTLBMiss:
> */
> /* Get PTE (linux-style) and check access */
> mfspr r3,SPRN_IMISS
> -#ifdef CONFIG_MODULES
> +#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) ||
> defined(CONFIG_KFENCE)
> lis r1, TASK_SIZE@h /* check if kernel address */
> cmplw 0,r1,r3
> #endif
> mfspr r2, SPRN_SDR1
> li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC | _PAGE_USER
> rlwinm r2, r2, 28, 0xfffff000
> -#ifdef CONFIG_MODULES
> +#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) ||
> defined(CONFIG_KFENCE)
> bgt- 112f
> lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address,
> use */
> li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
