Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752283AbdHJNBM (ORCPT ); Thu, 10 Aug 2017 09:01:12 -0400 Received: from mail-qk0-f193.google.com ([209.85.220.193]:38254 "EHLO mail-qk0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387AbdHJNBL (ORCPT ); Thu, 10 Aug 2017 09:01:11 -0400 Date: Thu, 10 Aug 2017 09:01:06 -0400 From: Konrad Rzeszutek Wilk To: Tycho Andersen Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Marco Benatto , Juerg Haefliger , Juerg Haefliger Subject: Re: [PATCH v5 03/10] swiotlb: Map the buffer if it was unmapped by XPFO Message-ID: <20170810130104.GB2413@localhost.localdomain> References: <20170809200755.11234-1-tycho@docker.com> <20170809200755.11234-4-tycho@docker.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170809200755.11234-4-tycho@docker.com> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2565 Lines: 72 On Wed, Aug 09, 2017 at 02:07:48PM -0600, Tycho Andersen wrote: > From: Juerg Haefliger > > Signed-off-by: Juerg Haefliger > Tested-by: Tycho Andersen > --- > include/linux/xpfo.h | 4 ++++ > lib/swiotlb.c | 3 ++- > mm/xpfo.c | 9 +++++++++ > 3 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h > index 1ff2d1976837..6b61f7b820f4 100644 > --- a/include/linux/xpfo.h > +++ b/include/linux/xpfo.h > @@ -27,6 +27,8 @@ void xpfo_kunmap(void *kaddr, struct page *page); > void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp); > void xpfo_free_pages(struct page *page, int order); > > +bool xpfo_page_is_unmapped(struct page *page); > + > #else /* !CONFIG_XPFO */ > > static inline void xpfo_kmap(void *kaddr, struct page *page) { } > @@ -34,6 +36,8 @@ static inline void xpfo_kunmap(void *kaddr, struct page *page) { } > static inline void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp) { } > static inline void xpfo_free_pages(struct page *page, int order) { } > > +static inline bool xpfo_page_is_unmapped(struct page *page) { return false; } > + > #endif /* CONFIG_XPFO */ > > #endif /* _LINUX_XPFO_H */ > diff --git a/lib/swiotlb.c b/lib/swiotlb.c > index a8d74a733a38..d4fee5ca2d9e 100644 > --- a/lib/swiotlb.c > +++ b/lib/swiotlb.c > @@ -420,8 +420,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, > { > unsigned long pfn = PFN_DOWN(orig_addr); > unsigned char *vaddr = phys_to_virt(tlb_addr); > + struct page *page = pfn_to_page(pfn); > > - if (PageHighMem(pfn_to_page(pfn))) { > + if (PageHighMem(page) || xpfo_page_is_unmapped(page)) { > /* The buffer does not have a mapping. Map it in and copy */ > unsigned int offset = orig_addr & ~PAGE_MASK; > char *buffer; > diff --git a/mm/xpfo.c b/mm/xpfo.c > index 3cd45f68b5ad..3f305f31a072 100644 > --- a/mm/xpfo.c > +++ b/mm/xpfo.c > @@ -206,3 +206,12 @@ void xpfo_kunmap(void *kaddr, struct page *page) > spin_unlock_irqrestore(&xpfo->maplock, flags); > } > EXPORT_SYMBOL(xpfo_kunmap); > + > +inline bool xpfo_page_is_unmapped(struct page *page) > +{ > + if (!static_branch_unlikely(&xpfo_inited)) > + return false; > + > + return test_bit(XPFO_PAGE_UNMAPPED, &lookup_xpfo(page)->flags); > +} > +EXPORT_SYMBOL(xpfo_page_is_unmapped); How can it be inline and 'EXPORT_SYMBOL' ? And why make it inline? It surely does not need to be access that often? > -- > 2.11.0 >