linux-kernel - Re: [PATCH] powerpc/book3e: redefine pte_mkprivileged() and pte

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Date:   Wed, 17 Oct 2018 18:53:54 +0530
From:   "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
To:     Christophe Leroy <christophe.leroy@....fr>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH] powerpc/book3e: redefine pte_mkprivileged() and
 pte_mkuser()

On 10/17/18 6:33 PM, Christophe Leroy wrote:
> Book3e defines both _PAGE_USER and _PAGE_PRIVILEGED, so the nohash
> default pte_mkprivileged() and pte_mkuser() are not usable.
> 
> This patch redefines them for book3e.
> 
> In theorie, only pte_mkprivileged() needs to be redefined because
> _PAGE_USER includes _PAGE_PRIVILEGED, but it is less confusing
> to redefine both.
> 
> Fixes: a0da4bc166f2 ("powerpc/mm: Allow platforms to redefine some helpers")

  Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@...ux.ibm.com>

> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---
>   arch/powerpc/include/asm/nohash/pte-book3e.h | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/nohash/pte-book3e.h b/arch/powerpc/include/asm/nohash/pte-book3e.h
> index 58eef8cb569d..fa1451e15b4e 100644
> --- a/arch/powerpc/include/asm/nohash/pte-book3e.h
> +++ b/arch/powerpc/include/asm/nohash/pte-book3e.h
> @@ -109,5 +109,21 @@
>   #define PAGE_READONLY	__pgprot(_PAGE_BASE | _PAGE_USER)
>   #define PAGE_READONLY_X	__pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
>   
> +#ifndef __ASSEMBLY__
> +static inline pte_t pte_mkprivileged(pte_t pte)
> +{
> +	return __pte((pte_val(pte) & ~_PAGE_USER) | _PAGE_PRIVILEGED);
> +}
> +
> +#define pte_mkprivileged pte_mkprivileged
> +
> +static inline pte_t pte_mkuser(pte_t pte)
> +{
> +	return __pte((pte_val(pte) & ~_PAGE_PRIVILEGED) | _PAGE_USER);
> +}
> +
> +#define pte_mkuser pte_mkuser
> +#endif /* __ASSEMBLY__ */
> +
>   #endif /* __KERNEL__ */
>   #endif /*  _ASM_POWERPC_NOHASH_PTE_BOOK3E_H */
>