On Wed, Oct 7, 2015 at 1:24 PM, Dave Hansen <d...@sr71.net> wrote: > On 10/03/2015 01:17 AM, Ingo Molnar wrote: >> Right now the native x86 PTE format allows two protection related bits for >> user-space pages: >> >> _PAGE_BIT_RW: if 0 the page is read-only, if 1 then >> it's read-write >> _PAGE_BIT_NX: if 0 the page is executable, if 1 then >> it's not executable >> >> As discussed previously, pkeys allows 'true execute only (--x)' mappings. >> >> Another possibility would be 'true write-only (-w-)' mappings. > > How would those work? > > Protection Keys has a Write-Disable and an Access-Disable bit. But, > Access-Disable denies _all_ data access to the region. There's no way > to allow only writes.
Weird. I wonder why Intel did that. I also wonder whether EPT can do write-only. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
