From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.cn.fujitsu.com ([183.91.158.132] helo=heian.cn.fujitsu.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h9OVp-0001pV-Ar for kexec@lists.infradead.org; Thu, 28 Mar 2019 06:27:42 +0000 Date: Thu, 28 Mar 2019 14:26:45 +0800 From: Chao Fan Subject: Re: [PATCH v2] x86/boot: Use EFI setup data if provided Message-ID: <20190328062645.GG4234@localhost.localdomain> References: <51D9A7D1-49BF-4679-B102-0FC5AC300C9F@alien8.de> <20190325101509.GA13160@dhcp-128-65.nay.redhat.com> <701c8e69-e1d4-c653-1d87-1c41789d3d54@ce.jp.nec.com> <20190325120149.GI12016@zn.tnic> <20190325122302.GC13160@dhcp-128-65.nay.redhat.com> <20190325123229.GL12016@zn.tnic> <20190325231000.GA9184@jeru.linux.bs1.fc.nec.co.jp> <20190326135714.GG1867@zn.tnic> <20190327014852.GA3659@MiWiFi-R3L-srv> <73322ba9-e436-68db-7863-afd31607d969@ce.jp.nec.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <73322ba9-e436-68db-7863-afd31607d969@ce.jp.nec.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Junichi Nomura Cc: "kasong@redhat.com" , "bhe@redhat.com" , "x86@kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Borislav Petkov , Dave Young On Thu, Mar 28, 2019 at 04:17:16AM +0000, Junichi Nomura wrote: >On 2019/03/27 10:48, bhe@redhat.com wrote: >>>> So efi_get_rsdp_addr() needs to be refactored in such a way so that at >>>> least the loop towards the end gets carved out into a separate function >>>> - __efi_get_rsdp_addr() or so - which gets config_tables, nr_tables and >>>> size as arguments and finds the RSDP address in the kexec-ed kernel. >>> >>> You need to carve out the loop at the end and make it into a separate >>> __efi_get_rsdp_addr() function which gets the physical or the virtual >>> address. >> >> I guess Boris is suggesting code like below. Please correct me if I am >> wrong. >> >> static acpi_physical_address _efi_get_rsdp_addr(efi_config_table tbl, ...) >> { >> /* Get EFI tables from systab. */ >> for (i = 0; i < nr_tables; i++) { >> ... >> } >> return rsdp_addr; >> } >> >> static acpi_physical_address efi_get_rsdp_addr(void) >> { >> ... >> /* Get systab from boot params. */ >> ... >> /* Handle EFI bitness properly */ >> ... >> return _efi_get_rsdp_addr(); >> } >> >> >> static acpi_physical_address kexec_get_rsdp_addr(void) >> { >> if (!is_kexec_booted) >> return 0; >> >> efi_get_setup_data_addr(); >> ... >> /* Handle EFI bitness properly */ >> ... >> return _efi_get_rsdp_addr(); >> } > >I still don't get it... We still need systab for kexec case as well >to get nr_tables. Don't we? > >> acpi_physical_address get_rsdp_addr(void) >> { >> acpi_physical_address pa; >> >> pa = get_acpi_rsdp(); >> >> if (!pa) >> pa = boot_params->acpi_rsdp_addr; >> >> >> /** >> /*I think here we should check if it's kexec booted firstly. >> * Skip it if not kexec. this can avoid the wrong kexec virt >> * addr parsing./ >> if (!pa) >> pa = kexec_get_rdsp_addr(); <--- new function >> >> if (!pa) >> pa = efi_get_rsdp_addr(); >> > >Shouldn't t efi_get_rsdp_addr() check "is_kexec_booted" and exit >early so that it never tries to use virtual config_tables pointer >if for some unknown resason kexec_get_rsdp_addr() failed. In my understanding, in EFI issue, RSDP is from efi_get_rsdp_addr() or kexec_get_rdsp_addr()(only in kexec environment). So in these two functions only one can be excuted, so how about this: if (is_kexec_booted) pa = kexec_get_rdsp_addr(); <--- new function else pa = efi_get_rsdp_addr(); And also split the same code as _efi_get_rsdp_addr(). If there is something wrong in my understanding, please let me know. Thanks, Chao Fan > >Currently I check "is_kexec_booted" by subset of efi_get_setup_data_addr(). >Do you know a simpler way to check "is_kexec_booted"? > >> if (!pa) >> pa = bios_get_rsdp_addr(); >> >> return pa; >> } > >-- >Jun'ichi Nomura, NEC Corporation / NEC Solution Innovators, Ltd. > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec