Re: [PATCH] powerpc/vdso: Separate vvar vma from vdso

From: Dmitry Safonov
Date: Wed Mar 31 2021 - 14:16:17 EST


On 3/30/21 11:17 AM, Christophe Leroy wrote:
>
>
> Le 26/03/2021 à 20:17, Dmitry Safonov a écrit :
[..]
>> --- a/arch/powerpc/kernel/vdso.c
>> +++ b/arch/powerpc/kernel/vdso.c
>> @@ -55,10 +55,10 @@ static int vdso_mremap(const struct
>> vm_special_mapping *sm, struct vm_area_struc
>>   {
>>       unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
>>   -    if (new_size != text_size + PAGE_SIZE)
>> +    if (new_size != text_size)
>>           return -EINVAL;
>
> In ARM64 you have removed the above test in commit 871402e05b24cb56
> ("mm: forbid splitting special mappings"). Do we need to keep it here ?
>
>>   -    current->mm->context.vdso = (void __user *)new_vma->vm_start +
>> PAGE_SIZE;
>> +    current->mm->context.vdso = (void __user *)new_vma->vm_start;
>>         return 0;
>>   }
>

Yes, right you are, this can be dropped.

Thanks,
Dmitry