Subject: Re: [PATCH v4 00/13] mm/debug_vm_pgtable fixes

From: Andrew Morton <[email-masked]>
Date: Wed, 14 Oct 2020 13:36:07 -0700

On Wed, 14 Oct 2020 08:45:16 +0530 "Aneesh Kumar K.V" <[email-masked]> wrote:

> > Against mm-debug_vm_pgtable-avoid-none-pte-in-pte_clear_test.patch:
> > 
> > https://lkml.kernel.org/r/[email-masked]
> 
> 
> yes this one we should get fixed. I was hoping someone familiar with 
> Riscv pte updates rules would pitch in. IIUC we need to update 
> RANDON_ORVALUE similar to how we updated it for s390 and ppc64.
> 
> 
>   Alternatively we can do this
> 
> modified   mm/debug_vm_pgtable.c
> @@ -548,7 +548,7 @@ static void __init pte_clear_tests(struct mm_struct 
> *mm, pte_t *ptep,
>   	pte_t pte = pfn_pte(pfn, prot);
> 
>   	pr_debug("Validating PTE clear\n");
> -	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
> +//	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
>   	set_pte_at(mm, vaddr, ptep, pte);
>   	barrier();
>   	pte_clear(mm, vaddr, ptep);
> 
> till we get that feedback from RiscV team?

Would it be better to do

#ifdef CONFIG_S390
	pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
#endif

?