Re: [PATCH] x86/EISA: Use memremap() to probe for the EISA BIOS signature

[Kirill A. Shutemov]

On Tue, Aug 27, 2024 at 11:14:45PM -0700, Christoph Hellwig wrote:
> On Sat, Aug 24, 2024 at 11:17:10PM +0100, Maciej W. Rozycki wrote:
> > -	void __iomem *p;
> > +	void *p;
> >  
> >  	if ((xen_pv_domain() && !xen_initial_domain()) || cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
> >  		return 0;
> >  
> > -	p = ioremap(0x0FFFD9, 4);
> > +	p = memremap(0x0FFFD9, 4, MEMREMAP_WB);
> >  	if (p && readl(p) == 'E' + ('I' << 8) + ('S' << 16) + ('A' << 24))
> >  		EISA_bus = 1;
> 
> readl requires and __iomem pointer.  If this is just a memory region you
> can and should directly dereference the address instead.
> 
> Note that sparse will complain about the above as well.
 
See v2:

https://lore.kernel.org/all/alpine.DEB.2.21.2408261015270.30766@xxxxxxxxxxxxxxxxx


-- 
  Kiryl Shutsemau / Kirill A. Shutemov