From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752144AbdBMKAm (ORCPT <rfc822;w@1wt.eu>);
        Mon, 13 Feb 2017 05:00:42 -0500
Received: from Galois.linutronix.de ([146.0.238.70]:38293 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751480AbdBMKAl (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Mon, 13 Feb 2017 05:00:41 -0500
Date: Mon, 13 Feb 2017 11:00:38 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Marc Zyngier <marc.zyngier@arm.com>
cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kvmarm@lists.cs.columbia.edu,
        Christoffer Dall <christoffer.dall@linaro.org>,
        Jason Cooper <jason@lakedaemon.net>,
        Eric Auger <eric.auger@redhat.com>
Subject: Re: [RFC PATCH 06/33] irqchip/gic-v3-its: Add probing for VLPI
 properties
In-Reply-To: <1484648454-21216-7-git-send-email-marc.zyngier@arm.com>
Message-ID: <alpine.DEB.2.20.1702131057290.3619@nanos>
References: <1484648454-21216-1-git-send-email-marc.zyngier@arm.com> <1484648454-21216-7-git-send-email-marc.zyngier@arm.com>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, 17 Jan 2017, Marc Zyngier wrote:
> +	typer = gic_read_typer(its_base + GITS_TYPER);
>  	its->base = its_base;
>  	its->phys_base = res->start;
> -	its->ite_size = ((gic_read_typer(its_base + GITS_TYPER) >> 4) & 0xf) + 1;
> +	its->ite_size = ((typer >> 4) & 0xf) + 1;
> +	its->is_v4 = !!(typer & GITS_TYPER_VLPIS);
> +	if (its->is_v4 && !(typer & GITS_TYPER_VMOVP)) {
> +		int its_number;
> +
> +		its_number = find_first_zero_bit(&its_list_map, 16);

s/16/ITS_MAX_ENTITIES or whatever.

> +		if (its_number >= 16) {
> +			pr_err("ITS@%pa: No ITSList entry available!\n",
> +			       &res->start);
> +			err = -EINVAL;
> +			goto out_free_its;
> +		}
> +
> +		ctlr = readl_relaxed(its_base + GITS_CTLR);
> +		ctlr &= ~GITS_CTLR_ITS_NUMBER;
> +		ctlr |= its_number << GITS_CTLR_ITS_NUMBER_SHIFT;
> +		writel_relaxed(ctlr, its_base + GITS_CTLR);
> +		ctlr = readl_relaxed(its_base + GITS_CTLR);
> +		if ((ctlr & GITS_CTLR_ITS_NUMBER) != (its_number << GITS_CTLR_ITS_NUMBER_SHIFT)) {
> +			its_number = ctlr & GITS_CTLR_ITS_NUMBER;
> +			its_number >>= GITS_CTLR_ITS_NUMBER_SHIFT;
> +		}
> +
> +		if (test_and_set_bit(its_number, &its_list_map)) {

You just established above that the bit is not set. I assume that this is
code which has no concurrency concerns....

Thanks,

	tglx