Re: [PATCHv7 10/19] x86/mm: Make __PHYSICAL_MASK_SHIFT and __VIRTUAL_MASK_SHIFT dynamic

[Ingo Molnar]

* Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote:

> On Thu, Sep 28, 2017 at 10:28:13AM +0200, Ingo Molnar wrote:
> > 
> > * Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
> > 
> > > --- a/arch/x86/mm/dump_pagetables.c
> > > +++ b/arch/x86/mm/dump_pagetables.c
> > > @@ -82,8 +82,8 @@ static struct addr_marker address_markers[] = {
> > >  	{ 0/* VMALLOC_START */, "vmalloc() Area" },
> > >  	{ 0/* VMEMMAP_START */, "Vmemmap" },
> > >  #ifdef CONFIG_KASAN
> > > -	{ KASAN_SHADOW_START,	"KASAN shadow" },
> > > -	{ KASAN_SHADOW_END,	"KASAN shadow end" },
> > > +	{ 0/* KASAN_SHADOW_START */,	"KASAN shadow" },
> > > +	{ 0/* KASAN_SHADOW_END */,	"KASAN shadow end" },
> > 
> > What's this? Looks hacky.
> 
> KASAN_SHADOW_START and KASAN_SHADOW_END depend on __VIRTUAL_MASK_SHIFT,
> which is dynamic for boot-time switching case. It means we cannot
> initialize the corresponding address_markers fields compile-time, so we do
> it boot-time.

Yes, so please instead of just commenting out the values, please do something like 
this:

	/*
	 * This field gets initialized with the (dynamic) KASAN_SHADOW_END value
	 * in boot_fn_foo() 
	 */
	{ 0, "KASAN shadow end" },

where boot_fn_foo() is the function where this all gets set up.

Thanks,

	Ingo