Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756427AbXKAEsx (ORCPT ); Thu, 1 Nov 2007 00:48:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752452AbXKAEsp (ORCPT ); Thu, 1 Nov 2007 00:48:45 -0400 Received: from gw.goop.org ([64.81.55.164]:43201 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753143AbXKAEso (ORCPT ); Thu, 1 Nov 2007 00:48:44 -0400 Message-ID: <47295AA7.9090507@goop.org> Date: Wed, 31 Oct 2007 21:48:39 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.5 (X11/20070727) MIME-Version: 1.0 To: Glauber de Oliveira Costa CC: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, rusty@rustcorp.com.au, ak@suse.de, mingo@elte.hu, chrisw@sous-sol.org, avi@qumranet.com, anthony@codemonkey.ws, virtualization@lists.linux-foundation.org, lguest@ozlabs.org, kvm-devel@lists.sourceforge.net, zach@vmware.com, tglx@linutronix.de, jun.nakajima@intel.com, glommer@gmail.com, Steven Rostedt Subject: Re: [PATCH 3/16] read/write_crX, clts and wbinvd for 64-bit paravirt References: <1193858101367-git-send-email-gcosta@redhat.com> <11938581073775-git-send-email-gcosta@redhat.com> <11938581133479-git-send-email-gcosta@redhat.com> <1193858118284-git-send-email-gcosta@redhat.com> In-Reply-To: <1193858118284-git-send-email-gcosta@redhat.com> X-Enigmail-Version: 0.95.4 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2699 Lines: 83 Glauber de Oliveira Costa wrote: > This patch introduces, and patch callers when needed, native > versions for read/write_crX functions, clts and wbinvd. > > Signed-off-by: Glauber de Oliveira Costa > Signed-off-by: Steven Rostedt > Acked-by: Jeremy Fitzhardinge > --- > arch/x86/mm/pageattr_64.c | 3 +- > include/asm-x86/system_64.h | 60 ++++++++++++++++++++++++++++++------------ > 2 files changed, 45 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/mm/pageattr_64.c b/arch/x86/mm/pageattr_64.c > index c40afba..59a52b0 100644 > --- a/arch/x86/mm/pageattr_64.c > +++ b/arch/x86/mm/pageattr_64.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > > pte_t *lookup_address(unsigned long address) > { > @@ -77,7 +78,7 @@ static void flush_kernel_map(void *arg) > much cheaper than WBINVD. */ > /* clflush is still broken. Disable for now. */ > if (1 || !cpu_has_clflush) > - asm volatile("wbinvd" ::: "memory"); > + wbinvd(); > else list_for_each_entry(pg, l, lru) { > void *adr = page_address(pg); > clflush_cache_range(adr, PAGE_SIZE); > diff --git a/include/asm-x86/system_64.h b/include/asm-x86/system_64.h > index 4cb2384..b558cb2 100644 > --- a/include/asm-x86/system_64.h > +++ b/include/asm-x86/system_64.h > @@ -65,53 +65,62 @@ extern void load_gs_index(unsigned); > /* > * Clear and set 'TS' bit respectively > */ > -#define clts() __asm__ __volatile__ ("clts") > +static inline void native_clts(void) > +{ > + asm volatile ("clts"); > +} > > -static inline unsigned long read_cr0(void) > -{ > +static inline unsigned long native_read_cr0(void) > +{ > unsigned long cr0; > asm volatile("movq %%cr0,%0" : "=r" (cr0)); > return cr0; > } > This is a pre-existing bug, but it seems to me that these read/write crX asms should have a constraint to stop the compiler from reordering them with respect to each other. The brute-force approach would be to add "memory" clobbers, but the subtle fix would be to add a variable which is only used to sequence: static int __cr_seq; static inline unsigned long native_read_cr0(void) { unsigned long cr0; asm volatile("mov %%cr0, %0" : "=r" (cr0), "=m" (__cr_seq)); } static inline void native_write_cr0(unsigned long val) { asm volatile("mov %1, %%cr0" : "+m" (__cr_seq) : "r" (val)); } J - 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/