Christophe Leroy [off-list ref] writes:

Le 07/11/2023 à 14:34, Aneesh Kumar K.V a écrit :

quoted

Christophe Leroy [off-list ref] writes:

quoted

Le 31/10/2023 à 11:15, Aneesh Kumar K.V a écrit :

quoted

Christophe Leroy [off-list ref] writes:

....

quoted

We are adding the pte flags check not the map addr check there. Something like this?

Well, ok, but then why do we want to do that check for ioremap() and not 
for everything else ? vmap() for instance will not perform any such 
check. All it does is to clear the EXEC bit.

As far as I can see, no other architecture does such a check, so why is 
it needed on powerpc at all ?

Regardless, comments below.

Looking at ioremap_prot() I am not clear whether we can really use the
flag value argument as is. For ex: x86 does 

pgprot2cachemode(__pgprot(prot_val))

I see that we use ioremap_prot() for generic_access_phys() and with
/dev/mem and __access_remote_vm() we can get called with a user pte
mapping prot flags? 

If such an prot value can be observed then the original change to clear
EXEC and mark it privileged is required?

	/* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
	pte = pte_exprotect(pte);
	pte = pte_mkprivileged(pte);


We already handle exec in pgprot_nx() and we need add back
pte_mkprivileged()? 


-aneesh