From: Dave Kleikamp <dave.kleikamp@oracle.com>
Date: Tue, 18 Jun 2013 14:05:36 +0000 (-0500)
Subject: sparc: tsb must be flushed before tlb
X-Git-Tag: v3.0.88~34
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=519d018ae15412bd501598872300d4c883197b44;p=thirdparty%2Fkernel%2Fstable.git

sparc: tsb must be flushed before tlb

upstream commit 23a01138efe216f8084cfaa74b0b90dd4b097441

This fixes a race where a cpu may re-load a tlb from a stale tsb right
after it has been flushed by a remote function call.

I still see some instability when stressing the system with parallel
kernel builds while creating memory pressure by writing to
/proc/sys/vm/nr_hugepages, but this patch improves the stability
significantly.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Acked-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index afd021ed94181..072f5530373e0 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -115,8 +115,8 @@ no_cache_flush:
 	}
 
 	if (!tb->active) {
-		global_flush_tlb_page(mm, vaddr);
 		flush_tsb_user_page(mm, vaddr);
+		global_flush_tlb_page(mm, vaddr);
 		goto out;
 	}