linux-kernel - [PATCH 1/3] x86/mm: only do a local TLB flush in ptep_set_access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 26 Oct 2012 14:44:19 -0400
From:	Rik van Riel <riel@...hat.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Andi Kleen <andi@...stfloor.org>,
	Michel Lespinasse <walken@...gle.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Mel Gorman <mgorman@...e.de>,
	Johannes Weiner <hannes@...xchg.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH 1/3] x86/mm: only do a local TLB flush in
 ptep_set_access_flags()

Here are the TLB patches as requested:
---8<---
    
The function ptep_set_access_flags() is only ever invoked to upgrade
access permissions on a PTE. That makes it safe to skip flushing the
TLBs on remote TLBs. The worst that can happen is a spurious page
fault on other CPUs, which would flush that TLB entry.

Lazily letting another CPU incur a spurious page fault occasionally
is (much!) cheaper than aggressively flushing everybody else's TLB.

Signed-off-by: Rik van Riel <riel@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Michel Lespinasse <walken@...gle.com>
Cc: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/mm/pgtable.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 8573b83..b3b852c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -310,7 +310,7 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
 	if (changed && dirty) {
 		*ptep = entry;
 		pte_update_defer(vma->vm_mm, address, ptep);
-		flush_tlb_page(vma, address);
+		__flush_tlb_one(address);
 	}
 
 	return changed;


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/