On Fri, 5 Jan 2018, Dave Hansen wrote: > >>> --- a/arch/x86/platform/efi/efi_64.c > >>> +++ b/arch/x86/platform/efi/efi_64.c > >>> @@ -95,6 +95,12 @@ pgd_t * __init efi_call_phys_prolog(void > >>> save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE); > >>> vaddress = (unsigned long)__va(pgd * PGDIR_SIZE); > >>> set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress)); > >>> + /* > >>> + * pgprot API doesn't clear it for PGD > >>> + * > >>> + * Will be brought back automatically in _epilog() > >>> + */ > >>> + pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX; > >>> } > >>> __flush_tlb_all(); > >> > >> Wait a sec... Where does the _PAGE_USER come from? Shouldn't we see > >> the &init_mm in there and *not* set _PAGE_USER? > > > > That's because pgd_populate() uses _PAGE_TABLE and not _KERNPG_TABLE for > > reasons that are behind me. > > > > I did put this on my TODO list, but for later. > > > > (and yes, I tried clearing _PAGE_USER from init_mm's PGD, and no obvious > > breakages appeared, but I wanted to give it more thought later). > > Feel free to add my Ack on this. Thanks. I'll extract the patch out of this thread and submit it separately, so that it doesn't get lost buried here. > I'd personally much rather muck with random relatively unused bits of > the efi code than touch the core PGD code. Exactly. Especially at this point. > We need to go look at it again in the 4.16 timeframe, probably. Agreed. On my TODO list already. Thanks, -- Jiri Kosina SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
