linux-kernel - Re: [PATCH v7 25/41] x86/mm: Introduce MAP

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Message-ID: <ca3e4a6abd0b3888110d65955c571d550138956d.camel@intel.com>
Date:   Tue, 7 Mar 2023 01:10:33 +0000
From:   "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
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Subject: Re: [PATCH v7 25/41] x86/mm: Introduce MAP_ABOVE4G

On Mon, 2023-03-06 at 19:09 +0100, Borislav Petkov wrote:
> > diff --git a/arch/x86/kernel/sys_x86_64.c
> > b/arch/x86/kernel/sys_x86_64.c
> > index 8cc653ffdccd..06378b5682c1 100644
> > --- a/arch/x86/kernel/sys_x86_64.c
> > +++ b/arch/x86/kernel/sys_x86_64.c
> > @@ -193,7 +193,11 @@ arch_get_unmapped_area_topdown(struct file
> > *filp, const unsigned long addr0,
> >   
> >        info.flags = VM_UNMAPPED_AREA_TOPDOWN;
> >        info.length = len;
> > -     info.low_limit = PAGE_SIZE;
> > +     if (!in_32bit_syscall() && (flags & MAP_ABOVE4G))
> > +             info.low_limit = 0x100000000;
> 
> We have a human readable define for that: SZ_4G

Uhh, yes that's much better. And the typos. Thanks.