From 510bb96fe5b3480b4b22d815786377e54cb701e7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 15 Apr 2019 10:46:07 +0200 Subject: x86/mm: Prevent bogus warnings with "noexec=off" Xose Vazquez Perez reported boot warnings when NX is disabled on the kernel command line. __early_set_fixmap() triggers this warning: attempted to set unsupported pgprot: 8000000000000163 bits: 8000000000000000 supported: 7fffffffffffffff WARNING: CPU: 0 PID: 0 at arch/x86/include/asm/pgtable.h:537 __early_set_fixmap+0xa2/0xff because it uses __default_kernel_pte_mask to mask out unsupported bits. Use __supported_pte_mask instead. Disabling NX on the command line also triggers the NX warning in the page table mapping check: WARNING: CPU: 1 PID: 1 at arch/x86/mm/dump_pagetables.c:262 note_page+0x2ae/0x650 .... Make the warning depend on NX set in __supported_pte_mask. Reported-by: Xose Vazquez Perez Tested-by: Xose Vazquez Perez Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1904151037530.1729@nanos.tec.linutronix.de Signed-off-by: Ingo Molnar --- arch/x86/mm/dump_pagetables.c | 3 ++- arch/x86/mm/ioremap.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index ee8f8ab46941..c0309ea9abee 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -259,7 +259,8 @@ static void note_wx(struct pg_state *st) #endif /* Account the WX pages */ st->wx_pages += npages; - WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n", + WARN_ONCE(__supported_pte_mask & _PAGE_NX, + "x86/mm: Found insecure W+X mapping at address %pS\n", (void *)st->start_address); } diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 0029604af8a4..dd73d5d74393 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -825,7 +825,7 @@ void __init __early_set_fixmap(enum fixed_addresses idx, pte = early_ioremap_pte(addr); /* Sanitize 'prot' against any unsupported bits: */ - pgprot_val(flags) &= __default_kernel_pte_mask; + pgprot_val(flags) &= __supported_pte_mask; if (pgprot_val(flags)) set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags)); -- cgit v1.2.3-59-g8ed1b