Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754706Ab2E1D4Y (ORCPT ); Sun, 27 May 2012 23:56:24 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51814 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753246Ab2E1D25 (ORCPT ); Sun, 27 May 2012 23:28:57 -0400 Message-Id: <20120528031204.684195488@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 28 May 2012 04:12:15 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, James Bottomley Subject: [ 013/117] [PARISC] fix panic on prefetch(NULL) on PA7300LC In-Reply-To: <20120528031202.829379252@decadent.org.uk> X-SA-Exim-Connect-IP: 192.168.4.185 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1500 Lines: 44 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: James Bottomley commit b3cb8674811d1851bbf1486a73d62b90c119b994 upstream. Due to an errata, the PA7300LC generates a TLB miss interruption even on the prefetch instruction. This means that prefetch(NULL), which is supposed to be a nop on linux actually generates a NULL deref fault. Fix this by testing the address of prefetch against NULL before doing the prefetch. Signed-off-by: James Bottomley Signed-off-by: Ben Hutchings --- arch/parisc/include/asm/prefetch.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/parisc/include/asm/prefetch.h b/arch/parisc/include/asm/prefetch.h index c5edc60..1ee7c82 100644 --- a/arch/parisc/include/asm/prefetch.h +++ b/arch/parisc/include/asm/prefetch.h @@ -21,7 +21,12 @@ #define ARCH_HAS_PREFETCH static inline void prefetch(const void *addr) { - __asm__("ldw 0(%0), %%r0" : : "r" (addr)); + __asm__( +#ifndef CONFIG_PA20 + /* Need to avoid prefetch of NULL on PA7300LC */ + " extrw,u,= %0,31,32,%%r0\n" +#endif + " ldw 0(%0), %%r0" : : "r" (addr)); } /* LDD is a PA2.0 addition. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/