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Subject: Re: [PATCH v28 16/32] x86/mm: Update maybe_mkwrite() for shadow stack
To:     Borislav Petkov <bp@alien8.de>
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References: <20210722205219.7934-1-yu-cheng.yu@intel.com>
 <20210722205219.7934-17-yu-cheng.yu@intel.com> <YRqaesuEy9ZGttZ6@zn.tnic>
From:   "Yu, Yu-cheng" <yu-cheng.yu@intel.com>
Message-ID: <87cbd676-5b60-da55-1f95-c5a6ae61e3fc@intel.com>
Date:   Tue, 17 Aug 2021 11:36:21 -0700
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On 8/16/2021 10:03 AM, Borislav Petkov wrote:
> On Thu, Jul 22, 2021 at 01:52:03PM -0700, Yu-cheng Yu wrote:
>> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
>> index 3364fe62b903..ba449d12ec32 100644
>> --- a/arch/x86/mm/pgtable.c
>> +++ b/arch/x86/mm/pgtable.c
>> @@ -610,6 +610,26 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
>>   }
>>   #endif
>>   
>> +pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
>> +{
>> +	if (likely(vma->vm_flags & VM_WRITE))
>> +		pte = pte_mkwrite(pte);
>> +	else if (likely(vma->vm_flags & VM_SHADOW_STACK))
>> +		pte = pte_mkwrite_shstk(pte);
>> +	return pte;
>> +}
>> +
>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> +pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
>> +{
>> +	if (likely(vma->vm_flags & VM_WRITE))
>> +		pmd = pmd_mkwrite(pmd);
>> +	else if (likely(vma->vm_flags & VM_SHADOW_STACK))
>> +		pmd = pmd_mkwrite_shstk(pmd);
> 
> What are all those likely()ies here for?
> 

I will remove those.

Thanks,
Yu-cheng