linux-kernel - Re: [PATCH v5 13/16] powerpc/mm/32s: Use BATs for STRICT_KERNEL

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Date:   Sun, 16 Jun 2019 10:45:46 +0200
From:   Andreas Schwab <schwab@...ux-m68k.org>
To:     christophe leroy <christophe.leroy@....fr>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, j.neuschaefer@....net,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v5 13/16] powerpc/mm/32s: Use BATs for STRICT_KERNEL_RWX

On Jun 16 2019, christophe leroy <christophe.leroy@....fr> wrote:

> Le 15/06/2019 à 14:28, Andreas Schwab a écrit :
>> On Feb 21 2019, Christophe Leroy <christophe.leroy@....fr> wrote:
>>
>>> diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
>>> index a000768a5cc9..6e56a6240bfa 100644
>>> --- a/arch/powerpc/mm/pgtable_32.c
>>> +++ b/arch/powerpc/mm/pgtable_32.c
>>> @@ -353,7 +353,10 @@ void mark_initmem_nx(void)
>>>   	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
>>>   				 PFN_DOWN((unsigned long)_sinittext);
>>>   -	change_page_attr(page, numpages, PAGE_KERNEL);
>>> +	if (v_block_mapped((unsigned long)_stext) + 1)
>>
>> That is always true.
>>
>
> Did you boot with 'nobats' kernel parameter ?
>
> If not, that's normal to be true, it means that memory is mapped with BATs.

bool + 1 is always true.

Andreas.

-- 
Andreas Schwab, schwab@...ux-m68k.org
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