Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753689AbbGBAAh (ORCPT ); Wed, 1 Jul 2015 20:00:37 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:46226 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752321AbbGBAAa (ORCPT ); Wed, 1 Jul 2015 20:00:30 -0400 Message-ID: <55947F1C.3020904@codeaurora.org> Date: Wed, 01 Jul 2015 17:00:28 -0700 From: Stephen Boyd User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Timur Tabi , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Shanker Donthineni , awallis@codeaurora.org, abhimany@codeaurora.org, will.deacon@arm.com, Vipul Gandhi Subject: Re: [PATCH 4/4] hvc_dcc: disable user-space access to DCC References: <1435699387-32591-1-git-send-email-timur@codeaurora.org> <1435699387-32591-4-git-send-email-timur@codeaurora.org> In-Reply-To: <1435699387-32591-4-git-send-email-timur@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2009 Lines: 78 On 06/30/2015 02:23 PM, Timur Tabi wrote: > diff --git a/arch/arm/include/asm/dcc.h b/arch/arm/include/asm/dcc.h > index b74899d..c50056b 100644 > --- a/arch/arm/include/asm/dcc.h > +++ b/arch/arm/include/asm/dcc.h > @@ -9,8 +9,11 @@ > * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > * GNU General Public License for more details. > */ > +#ifndef __ASM_DCC_H > +#define __ASM_DCC_H > > #include > +#include That's new. > > static inline u32 __dcc_getstatus(void) > { > @@ -39,3 +42,15 @@ static inline void __dcc_putchar(char c) > : "r" (c)); > isb(); > } > + > +static inline void __dcc_initialize(void) > +{ > + u32 val; > + > + /* Disable user-space access to DCC */ > + val = MRC14(0, c0, c1, 0); > + val |= 1 << 12; /* DSCR[Comms] */ > + MCR14(val, 0, c0, c1, 0); > +} Nitpick: We do raw cp14 accesses for other functions in this file, so it would be nice to be consistent throughout. > + > +#endif > diff --git a/arch/arm64/include/asm/dcc.h b/arch/arm64/include/asm/dcc.h > index fcb8d7d..7843e62 100644 > --- a/arch/arm64/include/asm/dcc.h > +++ b/arch/arm64/include/asm/dcc.h > @@ -49,4 +49,15 @@ static inline void __dcc_putchar(char c) > isb(); > } > > +static inline void __dcc_initialize(void) > +{ > + u32 val; > + > + /* Disable user-space access to DCC */ > + asm ("mrs %0, mdscr_el1\n" shouldn't this be volatile? > + " orr %0, %0, #4096\n" /* Set the TDCC bit */ arm64 has some #defines in debug-monitors.h which we should probably extend to have this bit as a #define too. > + " msr mdscr_el1, %0\n" > + : "=r" (val)); > +} > + > #endif > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- 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/