From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756406AbcBPXI3 (ORCPT ); Tue, 16 Feb 2016 18:08:29 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:43929 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756382AbcBPXI2 (ORCPT ); Tue, 16 Feb 2016 18:08:28 -0500 Subject: Re: [PATCH] irqchip/gicv3-its: Avoid cache flush beyond ITS_BASERn memory size To: Marc Zyngier References: <1455594112-27783-1-git-send-email-shankerd@codeaurora.org> <20160216083549.5c889627@arm.com> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Vikram Sethi , Jason Cooper , Thomas Gleixner From: Shanker Donthineni Message-ID: <56C3ABE9.9070302@codeaurora.org> Date: Tue, 16 Feb 2016 17:08:25 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20160216083549.5c889627@arm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marc, On 02/16/2016 02:35 AM, Marc Zyngier wrote: > 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. I will change to PAGE_ORDER_TO_SIZE in v2 patch. >> 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... Sure, I will keep it on the same line in v2 patch. >> } >> 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.