Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750906AbWIZJ2G (ORCPT ); Tue, 26 Sep 2006 05:28:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750923AbWIZJ2G (ORCPT ); Tue, 26 Sep 2006 05:28:06 -0400 Received: from ns.miraclelinux.com ([219.118.163.66]:29539 "EHLO mail01.miraclelinux.com") by vger.kernel.org with ESMTP id S1750906AbWIZJ2D (ORCPT ); Tue, 26 Sep 2006 05:28:03 -0400 To: Andrew Morton Cc: linux-kernel@vger.kernel.org, OGAWA Hirofumi Subject: [PATCH] arch/i386/pci/mmconfig.c tlb flush fix From: OGAWA Hirofumi Date: Tue, 26 Sep 2006 18:28:01 +0900 Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2793 Lines: 77 Hi, We use the fixmap for accessing pci config space in pci_mmcfg_read/write(). The problem is in pci_exp_set_dev_base(). It is caching a last accessed address to avoid calling set_fixmap_nocache() whenever pci_mmcfg_read/write() is used. static inline void pci_exp_set_dev_base(int bus, int devfn) { u32 dev_base = base | (bus << 20) | (devfn << 12); if (dev_base != mmcfg_last_accessed_device) { mmcfg_last_accessed_device = dev_base; set_fixmap_nocache(FIX_PCIE_MCFG, dev_base); } } cpu0 cpu1 --------------------------------------------------------------------------- pci_mmcfg_read("device-A") pci_exp_set_dev_base() set_fixmap_nocache() pci_mmcfg_read("device-B") pci_exp_set_dev_base() set_fixmap_nocache() pci_mmcfg_read("device-B") pci_exp_set_dev_base() /* doesn't flush tlb */ But if cpus accessed the above order, the second pci_mmcfg_read() on cpu0 doesn't flush the TLB, because "mmcfg_last_accessed_device" is device-B. So, second pci_mmcfg_read() on cpu0 accesses a device-A via a previous TLB cache. This patches fixes this situation by adds "mmcfg_last_accessed_cpu" check. Please apply. Signed-off-by: OGAWA Hirofumi --- arch/i386/pci/mmconfig.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff -puN arch/i386/pci/mmconfig.c~mmconfig-tlb-race-fix arch/i386/pci/mmconfig.c --- linux-2.6/arch/i386/pci/mmconfig.c~mmconfig-tlb-race-fix 2006-09-26 11:35:54.000000000 +0900 +++ linux-2.6-hirofumi/arch/i386/pci/mmconfig.c 2006-09-26 11:36:54.000000000 +0900 @@ -26,6 +26,7 @@ /* The base address of the last MMCONFIG device accessed */ static u32 mmcfg_last_accessed_device; +static int mmcfg_last_accessed_cpu; static DECLARE_BITMAP(fallback_slots, MAX_CHECK_BUS*32); @@ -70,8 +71,11 @@ static u32 get_base_addr(unsigned int se static inline void pci_exp_set_dev_base(unsigned int base, int bus, int devfn) { u32 dev_base = base | (bus << 20) | (devfn << 12); - if (dev_base != mmcfg_last_accessed_device) { + int cpu = smp_processor_id(); + if (dev_base != mmcfg_last_accessed_device || + cpu != mmcfg_last_accessed_cpu) { mmcfg_last_accessed_device = dev_base; + mmcfg_last_accessed_cpu = cpu; set_fixmap_nocache(FIX_PCIE_MCFG, dev_base); } } _ -- OGAWA Hirofumi - 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/