From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932902Ab3BZX6V (ORCPT ); Tue, 26 Feb 2013 18:58:21 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:42148 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932469Ab3BZX6P (ORCPT ); Tue, 26 Feb 2013 18:58:15 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John David Anglin , James Bottomley Subject: [ 112/150] [PARISC] Purge existing TLB entries in set_pte_at and ptep_set_wrprotect Date: Tue, 26 Feb 2013 15:56:09 -0800 Message-Id: <20130226235535.730234771@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130226235523.930663721@linuxfoundation.org> References: <20130226235523.930663721@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: John David Anglin commit 7139bc1579901b53db7e898789e916ee2fb52d78 upstream. This patch goes a long way toward fixing the minifail bug, and it  significantly improves the stability of SMP machines such as the rp3440.  When write  protecting a page for COW, we need to purge the existing translation.  Otherwise, the COW break doesn't occur as expected because the TLB may still have a stale entry which allows writes. [jejb: fix up checkpatch errors] Signed-off-by: John David Anglin Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman --- arch/parisc/include/asm/pgtable.h | 13 ++++++++++--- arch/parisc/kernel/cache.c | 18 ++++++++++++++++++ 2 files changed, 28 insertions(+), 3 deletions(-) --- a/arch/parisc/include/asm/pgtable.h +++ b/arch/parisc/include/asm/pgtable.h @@ -12,11 +12,10 @@ #include #include +#include #include #include -struct vm_area_struct; - /* * kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel * memory. For the return value to be meaningful, ADDR must be >= @@ -40,7 +39,14 @@ struct vm_area_struct; do{ \ *(pteptr) = (pteval); \ } while(0) -#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) + +extern void purge_tlb_entries(struct mm_struct *, unsigned long); + +#define set_pte_at(mm, addr, ptep, pteval) \ + do { \ + set_pte(ptep, pteval); \ + purge_tlb_entries(mm, addr); \ + } while (0) #endif /* !__ASSEMBLY__ */ @@ -466,6 +472,7 @@ static inline void ptep_set_wrprotect(st old = pte_val(*ptep); new = pte_val(pte_wrprotect(__pte (old))); } while (cmpxchg((unsigned long *) ptep, old, new) != old); + purge_tlb_entries(mm, addr); #else pte_t old_pte = *ptep; set_pte_at(mm, addr, ptep, pte_wrprotect(old_pte)); --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -419,6 +419,24 @@ void kunmap_parisc(void *addr) EXPORT_SYMBOL(kunmap_parisc); #endif +void purge_tlb_entries(struct mm_struct *mm, unsigned long addr) +{ + unsigned long flags; + + /* Note: purge_tlb_entries can be called at startup with + no context. */ + + /* Disable preemption while we play with %sr1. */ + preempt_disable(); + mtsp(mm->context, 1); + purge_tlb_start(flags); + pdtlb(addr); + pitlb(addr); + purge_tlb_end(flags); + preempt_enable(); +} +EXPORT_SYMBOL(purge_tlb_entries); + void __flush_tlb_range(unsigned long sid, unsigned long start, unsigned long end) {