Re: [PATCH 26/26] x86/mm: allow to have userspace mappings above 47-bits

[Kirill A. Shutemov]

On Mon, Mar 20, 2017 at 10:40:20AM +0530, Aneesh Kumar K.V wrote:
> "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> writes:
>  @@ -168,6 +182,10 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
> >  	unsigned long addr = addr0;
> >  	struct vm_unmapped_area_info info;
> >  
> > +	addr = mpx_unmapped_area_check(addr, len, flags);
> > +	if (IS_ERR_VALUE(addr))
> > +		return addr;
> > +
> >  	/* requested length too big for entire address space */
> >  	if (len > TASK_SIZE)
> >  		return -ENOMEM;
> > @@ -192,6 +210,14 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
> >  	info.length = len;
> >  	info.low_limit = PAGE_SIZE;
> >  	info.high_limit = mm->mmap_base;
> > +
> > +	/*
> > +	 * If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
> > +	 * in the full address space.
> > +	 */
> > +	if (addr > DEFAULT_MAP_WINDOW)
> > +		info.high_limit += TASK_SIZE - DEFAULT_MAP_WINDOW;
> > +
> 
> Is this ok for 32 bit application ?

DEFAULT_MAP_WINDOW is equal to TASK_SIZE on 32-bit, so it's nop and will
be compile out.

-- 
 Kirill A. Shutemov