From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp00.avonet.cz (smtp00.avonet.cz [217.112.162.55]) by sourceware.org (Postfix) with ESMTP id E78B93858C00 for ; Tue, 8 Nov 2022 15:58:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org E78B93858C00 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=fbl.cz Authentication-Results: sourceware.org; spf=fail smtp.mailfrom=fbl.cz Received: from ktus.lan (217-115-245-101.cust.avonet.cz [217.115.245.101]) by smtp00.avonet.cz (Postfix) with ESMTP id 4N6CSH3YXSz1xqF for ; Tue, 8 Nov 2022 16:58:23 +0100 (CET) Received: by ktus.lan (Postfix, from userid 209) id 64E14310619; Tue, 8 Nov 2022 16:58:23 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-Spam-Level: X-Spam-Status: No, score=-10.9 required=5.0 tests=BAYES_00,BODY_8BITS,GIT_PATCH_0,KAM_DMARC_STATUS,LIKELY_SPAM_BODY,NICE_REPLY_A,SPF_FAIL,SPF_HELO_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 Received: from [192.168.33.9] (217-115-245-101.cust.avonet.cz [217.115.245.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vanekt) by ktus.lan (Postfix) with ESMTPSA id BA912310615; Tue, 8 Nov 2022 16:58:19 +0100 (CET) Message-ID: <6bdb8d6d-c0f7-c154-c0a9-4897759fce91@fbl.cz> Date: Tue, 8 Nov 2022 16:58:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.13.1 Subject: Re: [RFC PATCH 1/5] gdb/arm: Introduce control_s and control_ns registers Content-Language: en-US From: Tomas Vanek To: Luis Machado , gdb-patches@sourceware.org References: <1667641476-31602-1-git-send-email-vanekt@fbl.cz> <3d6331d0-d1b3-03f7-0b2c-97b0784fa31e@fbl.cz> In-Reply-To: <3d6331d0-d1b3-03f7-0b2c-97b0784fa31e@fbl.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit List-Id: On 08/11/2022 16:52, Tomas Vanek wrote: > Hi Luis, > > On 08/11/2022 12:23, Luis Machado wrote: >> Hi Tomas, >> >> On 11/5/22 09:44, Tomas Vanek wrote: >>> The M-profile security extension registers will be used for stack >>> selection in FNC_RETURN and return from secure to non-secure state. >>> >>> The presence of the registers is optional. >>> If one or both are missing the security extension profile is accepted. >>> The code using the registers must check m_profile_control_[n]?s_regnum >>> for -1. >>> >>> Signed-off-by: Tomas Vanek >>> --- >>>   gdb/arm-tdep.c | 20 ++++++++++++++++++++ >>>   gdb/arm-tdep.h |  2 ++ >>>   2 files changed, 22 insertions(+) >>> >>> diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c >>> index 3105543..564ee43 100644 >>> --- a/gdb/arm-tdep.c >>> +++ b/gdb/arm-tdep.c >>> @@ -9996,6 +9996,8 @@ enum arm_vfp_cprc_base_type >>>     int m_profile_psp_ns_regnum = -1; >>>     int m_profile_msp_s_regnum = -1; >>>     int m_profile_psp_s_regnum = -1; >>> +  int m_profile_control_s_regnum = -1; >>> +  int m_profile_control_ns_regnum = -1; >>>     int tls_regnum = 0; >>>       /* If we have an object to base this architecture on, try to >>> determine >>> @@ -10473,6 +10475,22 @@ enum arm_vfp_cprc_base_type >>>           } >>>             m_profile_psp_s_regnum = register_count++; >>>   +          /* Regard the control_s and control_ns registers optional, >>> +           * accept the security extension feature even without >>> them */ >>> +          valid_p = tdesc_numbered_register (feature, >>> tdesc_data.get (), >>> +                         register_count, "control_s"); >> >> What tools are advertising control_s and control_ns? We need to >> document those properly if we're planning on using them >> as part of decision-making in GDB. > > Good question. > > OpenOCD exposes them, like other M-profile security extension > registers they have the feature name "v8-m.sp". > There is a pending patch to change the feature name to > "org.gnu.gdb.arm.secext" > 7265: target/armv7m: fix feature name of ARMv8M security extension > regs | https://review.openocd.org/c/openocd/+/7265 > > PyOCD exposes them, like other M-profile security extension registers > they have the feature name "v8-m.sp". Oops, PyOCD exposes just control, no control_s and control_ns variants. > > ST-LINK GDB server. Version 5.6.0 (I assume not the latest version) > exposes them (and other M-profile security extension registers too) > in the feature "org.gnu.gdb.arm.vfp"?? Obviously a bug! > > I have no access to Keil tools. > > Please be aware that control_s and control_ns are optional, the most > of security extension support is functional > even in the case they are not accessible in the connected gdbserver. > >> >> >>> +          if (!valid_p) >>> +        warning (_("M-profile secext feature is missing required >>> register control_s.")); >>> +          else >>> +        m_profile_control_s_regnum = register_count++; >>> + >>> +          valid_p = tdesc_numbered_register (feature, >>> tdesc_data.get (), >>> +                         register_count, "control_ns"); >>> +          if (!valid_p) >>> +        warning (_("M-profile secext feature is missing required >>> register control_ns.")); >>> +          else >>> +        m_profile_control_ns_regnum = register_count++; >>> + >>>             have_sec_ext = true; >>>           } >>>   @@ -10553,6 +10571,8 @@ enum arm_vfp_cprc_base_type >>>         tdep->m_profile_psp_ns_regnum = m_profile_psp_ns_regnum; >>>         tdep->m_profile_msp_s_regnum = m_profile_msp_s_regnum; >>>         tdep->m_profile_psp_s_regnum = m_profile_psp_s_regnum; >>> +      tdep->m_profile_control_s_regnum = m_profile_control_s_regnum; >>> +      tdep->m_profile_control_ns_regnum = m_profile_control_ns_regnum; >>>       } >>>       arm_register_g_packet_guesses (gdbarch); >>> diff --git a/gdb/arm-tdep.h b/gdb/arm-tdep.h >>> index bcd7e08..11670e9 100644 >>> --- a/gdb/arm-tdep.h >>> +++ b/gdb/arm-tdep.h >>> @@ -133,6 +133,8 @@ struct arm_gdbarch_tdep : gdbarch_tdep_base >>>     int m_profile_psp_ns_regnum = ARM_SP_REGNUM;    /* M-profile >>> PSP_NS register number.  */ >>>     int m_profile_msp_s_regnum = ARM_SP_REGNUM;    /* M-profile >>> MSP_S register number.  */ >>>     int m_profile_psp_s_regnum = ARM_SP_REGNUM;    /* M-profile >>> PSP_S register number.  */ >>> +  int m_profile_control_s_regnum = -1;        /* M-profile >>> CONTROL_S register number.  */ >>> +  int m_profile_control_ns_regnum = -1;        /* M-profile >>> CONTROL_NS register number.  */ >>>       int tls_regnum = 0;        /* Number of the tpidruro >>> register.  */ >> >