From patchwork Fri Jun 5 06:35:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Kardashevskiy X-Patchwork-Id: 481085 X-Patchwork-Delegate: michael@ellerman.id.au Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 902AF14016A for ; Fri, 5 Jun 2015 17:24:07 +1000 (AEST) Received: from ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 72D391A35BA for ; Fri, 5 Jun 2015 17:24:07 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from e23smtp09.au.ibm.com (e23smtp09.au.ibm.com [202.81.31.142]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 253891A0919 for ; Fri, 5 Jun 2015 16:38:16 +1000 (AEST) Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 5 Jun 2015 16:38:13 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id E03B83578063 for ; Fri, 5 Jun 2015 16:38:12 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t556aobX65470636 for ; Fri, 5 Jun 2015 16:36:58 +1000 Received: from d23av03.au.ibm.com (localhost [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t556aPNe015295 for ; Fri, 5 Jun 2015 16:36:25 +1000 Received: from ozlabs.au.ibm.com (ozlabs.au.ibm.com [9.192.253.14]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id t556aPKd014627; Fri, 5 Jun 2015 16:36:25 +1000 Received: from bran.ozlabs.ibm.com (unknown [9.192.254.114]) by ozlabs.au.ibm.com (Postfix) with ESMTP id C0992A03F2; Fri, 5 Jun 2015 16:35:39 +1000 (AEST) Received: from ka1.ozlabs.ibm.com (ka1.ozlabs.ibm.com [10.61.145.11]) by bran.ozlabs.ibm.com (Postfix) with ESMTP id 283C2E3897; Fri, 5 Jun 2015 16:35:37 +1000 (AEST) From: Alexey Kardashevskiy To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH kernel v12 19/34] powerpc/iommu: Fix IOMMU ownership control functions Date: Fri, 5 Jun 2015 16:35:11 +1000 Message-Id: <1433486126-23551-20-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 2.4.0.rc3.8.gfb3e7d5 In-Reply-To: <1433486126-23551-1-git-send-email-aik@ozlabs.ru> References: <1433486126-23551-1-git-send-email-aik@ozlabs.ru> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15060506-0033-0000-0000-0000019C0073 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wei Yang , Alexey Kardashevskiy , Gavin Shan , linux-kernel@vger.kernel.org, Alex Williamson , Paul Mackerras , David Gibson MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" This adds missing locks in iommu_take_ownership()/ iommu_release_ownership(). This marks all pages busy in iommu_table::it_map in order to catch errors if there is an attempt to use this table while ownership over it is taken. This only clears TCE content if there is no page marked busy in it_map. Clearing must be done outside of the table locks as iommu_clear_tce() called from iommu_clear_tces_and_put_pages() does this. In order to use bitmap_empty(), the existing code clears bit#0 which is set even in an empty table if it is bus-mapped at 0 as iommu_init_table() reserves page#0 to prevent buggy drivers from crashing when allocated page is bus-mapped at zero (which is correct). This restores the bit in the case of failure to bring the it_map to the state it was in when we called iommu_take_ownership(). Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Reviewed-by: Gavin Shan --- Changes: v9: * iommu_table_take_ownership() did not return @ret (and ignored EBUSY), now it does return correct error. * updated commit log about setting bit#0 in the case of failure v5: * do not store bit#0 value, it has to be set for zero-based table anyway * removed test_and_clear_bit --- arch/powerpc/kernel/iommu.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index e7f81b7..0fb8800 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1035,31 +1035,51 @@ EXPORT_SYMBOL_GPL(iommu_tce_build); int iommu_take_ownership(struct iommu_table *tbl) { - unsigned long sz = (tbl->it_size + 7) >> 3; + unsigned long flags, i, sz = (tbl->it_size + 7) >> 3; + int ret = 0; + + spin_lock_irqsave(&tbl->large_pool.lock, flags); + for (i = 0; i < tbl->nr_pools; i++) + spin_lock(&tbl->pools[i].lock); if (tbl->it_offset == 0) clear_bit(0, tbl->it_map); if (!bitmap_empty(tbl->it_map, tbl->it_size)) { pr_err("iommu_tce: it_map is not empty"); - return -EBUSY; + ret = -EBUSY; + /* Restore bit#0 set by iommu_init_table() */ + if (tbl->it_offset == 0) + set_bit(0, tbl->it_map); + } else { + memset(tbl->it_map, 0xff, sz); } - memset(tbl->it_map, 0xff, sz); + for (i = 0; i < tbl->nr_pools; i++) + spin_unlock(&tbl->pools[i].lock); + spin_unlock_irqrestore(&tbl->large_pool.lock, flags); - return 0; + return ret; } EXPORT_SYMBOL_GPL(iommu_take_ownership); void iommu_release_ownership(struct iommu_table *tbl) { - unsigned long sz = (tbl->it_size + 7) >> 3; + unsigned long flags, i, sz = (tbl->it_size + 7) >> 3; + + spin_lock_irqsave(&tbl->large_pool.lock, flags); + for (i = 0; i < tbl->nr_pools; i++) + spin_lock(&tbl->pools[i].lock); memset(tbl->it_map, 0, sz); /* Restore bit#0 set by iommu_init_table() */ if (tbl->it_offset == 0) set_bit(0, tbl->it_map); + + for (i = 0; i < tbl->nr_pools; i++) + spin_unlock(&tbl->pools[i].lock); + spin_unlock_irqrestore(&tbl->large_pool.lock, flags); } EXPORT_SYMBOL_GPL(iommu_release_ownership);