From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753628AbcBPIgA (ORCPT ); Tue, 16 Feb 2016 03:36:00 -0500 Received: from foss.arm.com ([217.140.101.70]:50672 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752290AbcBPIf7 (ORCPT ); Tue, 16 Feb 2016 03:35:59 -0500 Date: Tue, 16 Feb 2016 08:35:49 +0000 From: Marc Zyngier To: Shanker Donthineni Cc: , , Vikram Sethi , Jason Cooper , Thomas Gleixner Subject: Re: [PATCH] irqchip/gicv3-its: Avoid cache flush beyond ITS_BASERn memory size Message-ID: <20160216083549.5c889627@arm.com> In-Reply-To: <1455594112-27783-1-git-send-email-shankerd@codeaurora.org> References: <1455594112-27783-1-git-send-email-shankerd@codeaurora.org> Organization: ARM Ltd X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; arm-unknown-linux-gnueabihf) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 15 Feb 2016 21:41:52 -0600 Shanker Donthineni wrote: > Function its_alloc_tables() maintains two local variables, "order" and > and "alloc_size", to hold memory size that has been allocated to > ITS_BASEn. We don't always refresh the variable alloc_size whenever > value of the variable order changes, causing the following two problems. > > - Cache flush operation with size more than required. > - Information reported by pr_info is not correct. > > Use a helper macro that converts page order to size in bytes instead of > variable "alloc_size" to fix both the problems. > > Signed-off-by: Shanker Donthineni > --- > drivers/irqchip/irq-gic-v3-its.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c > index 0a73632..6f717f7 100644 > --- a/drivers/irqchip/irq-gic-v3-its.c > +++ b/drivers/irqchip/irq-gic-v3-its.c > @@ -78,6 +78,9 @@ struct its_node { > > #define ITS_ITT_ALIGN SZ_256 > > +/* Convert page order to size in bytes */ > +#define PAGE_ORDER_TO_BYTES(o) (PAGE_SIZE << (o)) > + nit: PAGE_ORDER_TO_size() seems more appropriate. > struct event_lpi_map { > unsigned long *lpi_map; > u16 *col_map; > @@ -846,7 +849,6 @@ static int its_alloc_tables(const char *node_name, struct its_node *its) > u64 type = GITS_BASER_TYPE(val); > u64 entry_size = GITS_BASER_ENTRY_SIZE(val); > int order = get_order(psz); > - int alloc_size; > int alloc_pages; > u64 tmp; > void *base; > @@ -878,9 +880,8 @@ static int its_alloc_tables(const char *node_name, struct its_node *its) > } > } > > - alloc_size = (1 << order) * PAGE_SIZE; > retry_alloc_baser: > - alloc_pages = (alloc_size / psz); > + alloc_pages = (PAGE_ORDER_TO_BYTES(order) / psz); > if (alloc_pages > GITS_BASER_PAGES_MAX) { > alloc_pages = GITS_BASER_PAGES_MAX; > order = get_order(GITS_BASER_PAGES_MAX * psz); > @@ -933,7 +934,8 @@ retry_baser: > shr = tmp & GITS_BASER_SHAREABILITY_MASK; > if (!shr) { > cache = GITS_BASER_nC; > - __flush_dcache_area(base, alloc_size); > + __flush_dcache_area(base, > + PAGE_ORDER_TO_BYTES(order)); Please keep it on the same line. It helps my random grepping... > } > goto retry_baser; > } > @@ -966,7 +968,7 @@ retry_baser: > } > > pr_info("ITS: allocated %d %s @%lx (psz %dK, shr %d)\n", > - (int)(alloc_size / entry_size), > + (int)(PAGE_ORDER_TO_BYTES(order) / entry_size), > its_base_type_string[type], > (unsigned long)virt_to_phys(base), > psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT); Otherwise looks good. Thanks, M. -- Jazz is not dead. It just smells funny.