# Re: \[PATCH 3/6\] powerpc/64s: Use htab\_convert\_pte\_flags() in hash\_\_mark\_rodata\_ro()

- From: Daniel Axtens \<hidden\>
- Date: 2021-02-16 05:51:26 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2021/02/9520959
- Thread: https://ratatoskr.run/linuxppc-dev/2021/02/9520919/t.md

```text
Hi Michael,

> In hash__mark_rodata_ro() we pass the raw PP_RXXX value to
> hash__change_memory_range(). That has the effect of setting the key to
> zero, because PP_RXXX contains no key value.
>
> Fix it by using htab_convert_pte_flags(), which knows how to convert a
> pgprot into a pp value, including the key.

So far as I can tell by chasing the definitions around, this appears
to do what it claims to do.

So, for what it's worth:
Reviewed-by: Daniel Axtens <redacted>

Kind regards,
Daniel

>
> Fixes: d94b827e89dc ("powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation")
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  arch/powerpc/mm/book3s64/hash_pgtable.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c
> index 567e0c6b3978..03819c259f0a 100644
> --- a/arch/powerpc/mm/book3s64/hash_pgtable.c
> +++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
> @@ -428,12 +428,14 @@ static bool hash__change_memory_range(unsigned long start, unsigned long end,
>  
>  void hash__mark_rodata_ro(void)
>  {
> -	unsigned long start, end;
> +	unsigned long start, end, pp;
>  
>  	start = (unsigned long)_stext;
>  	end = (unsigned long)__init_begin;
>  
> -	WARN_ON(!hash__change_memory_range(start, end, PP_RXXX));
> +	pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL_ROX), HPTE_USE_KERNEL_KEY);
> +
> +	WARN_ON(!hash__change_memory_range(start, end, pp));
>  }
>  
>  void hash__mark_initmem_nx(void)
> -- 
> 2.25.1
```