From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: Reza Arbab <arbab@linux.ibm.com>, linuxppc-dev@lists.ozlabs.org
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Charles Johns <crjohns@us.ibm.com>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [PATCH] powerpc/mm: Add _PAGE_SAO to _PAGE_CACHE_CTL mask
Date: Tue, 29 Jan 2019 12:39:31 +1100 [thread overview]
Message-ID: <6645ee79-c1b2-cb0d-455c-337b41bf4f5b@ozlabs.ru> (raw)
In-Reply-To: <1548696702-20686-1-git-send-email-arbab@linux.ibm.com>
On 29/01/2019 04:31, Reza Arbab wrote:
> In htab_convert_pte_flags(), _PAGE_CACHE_CTL is used to check for the
> _PAGE_SAO flag:
>
> else if ((pteflags & _PAGE_CACHE_CTL) == _PAGE_SAO)
> rflags |= (HPTE_R_W | HPTE_R_I | HPTE_R_M);
>
> But, it isn't defined to include that flag:
>
> #define _PAGE_CACHE_CTL (_PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
>
> This happens to work, but only because of the flag values:
>
> #define _PAGE_SAO 0x00010 /* Strong access order */
> #define _PAGE_NON_IDEMPOTENT 0x00020 /* non idempotent memory */
> #define _PAGE_TOLERANT 0x00030 /* tolerant memory, cache inhibited */
>
> To prevent any issues if these particulars ever change, add _PAGE_SAO to
> the mask.
This does not feel right, doing
#define _PAGE_CACHE_CTL 0x30
would make more sense as SAO/NI/TOLERANT is enum so applying "|" to them
just seems wrong.
>
> Suggested-by: Charles Johns <crjohns@us.ibm.com>
> Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
> ---
> arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 2e6ada2..1d97a28 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -811,7 +811,7 @@ static inline void __set_pte_at(struct mm_struct *mm, unsigned long addr,
> return hash__set_pte_at(mm, addr, ptep, pte, percpu);
> }
>
> -#define _PAGE_CACHE_CTL (_PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
> +#define _PAGE_CACHE_CTL (_PAGE_SAO | _PAGE_NON_IDEMPOTENT | _PAGE_TOLERANT)
>
> #define pgprot_noncached pgprot_noncached
> static inline pgprot_t pgprot_noncached(pgprot_t prot)
>
--
Alexey
next prev parent reply other threads:[~2019-01-29 1:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-28 17:31 [PATCH] powerpc/mm: Add _PAGE_SAO to _PAGE_CACHE_CTL mask Reza Arbab
2019-01-29 1:39 ` Alexey Kardashevskiy [this message]
2019-01-29 15:07 ` Aneesh Kumar K.V
2019-01-29 17:03 ` Reza Arbab
2019-01-30 13:35 ` Michael Ellerman
2019-02-01 5:02 ` Alexey Kardashevskiy
2019-02-08 13:02 ` Michael Ellerman
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