From: Chao Fan <fanc.fnst@cn.fujitsu.com> To: Borislav Petkov <bp@alien8.de> Cc: Junichi Nomura <j-nomura@ce.jp.nec.com>, "bhe@redhat.com" <bhe@redhat.com>, Dave Young <dyoung@redhat.com>, "kasong@redhat.com" <kasong@redhat.com>, "x86@kernel.org" <x86@kernel.org>, "kexec@lists.infradead.org" <kexec@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v2] x86/boot: Use EFI setup data if provided Date: Fri, 29 Mar 2019 17:05:50 +0800 [thread overview] Message-ID: <20190329090550.GI4234@localhost.localdomain> (raw) In-Reply-To: <20190329083920.GA21152@zn.tnic> On Fri, Mar 29, 2019 at 09:39:20AM +0100, Borislav Petkov wrote: >On Fri, Mar 29, 2019 at 03:05:52AM +0000, Junichi Nomura wrote: >> > You don't need that variable and can return "table" or 0 after the endif >> > below. >> >> I could do that but it will slightly change the current logic. >> >> Existing code does this: >> >> if (!(efi_guidcmp(guid, ACPI_TABLE_GUID))) >> rsdp_addr = table; >> else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) >> return table; >> >> I thought it was to return the table for ACPI_20_TABLE_GUID >> if both tables exist. If we remove rsdp_addr, the code will be: >> >> if (!(efi_guidcmp(guid, ACPI_TABLE_GUID))) >> return table; >> else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) >> return table; >> >> So if there are 2 tables, we return the one that comes first. >> Is it ok? > >That's a good question. > >Chao, what was the intention there, ACPI_20_TABLE_GUID is the preferred >table to return? If so, why? Yes, ACPI_20_TABLE_GUID is preferred. ACPI_20 means version 2.0 and later versions, ACPI_TABLE_GUID is version 1.0 which is earlier than 2003, it's too old. Version 2.0 has more features than 1.0. Sure the new version is preferred. So many codes prefers ACPI20, such as in drivers/acpi/osl.c where kernel parses RSDP ACPI20 firstly. Documentation/ABI/testing/sysfs-firmware-efi says in /sys/firmware/efi/systab, ACPI20 comes before ACPI. So that kexec-tools code kexec/arch/i386/crashdump-x86.c can easily get ACPI_20(if there is ACPI_20) before ACPI 1.0. But in my code, I am not sure which version will be found firstly, so I write this logical, if ACPI20 found, return directly, then consider ACPI 1.0. Thanks, Chao Fan >-- >Regards/Gruss, > Boris. > >Good mailing practices for 400: avoid top-posting and trim the reply. > >
WARNING: multiple messages have this Message-ID (diff)
From: Chao Fan <fanc.fnst@cn.fujitsu.com> To: Borislav Petkov <bp@alien8.de> Cc: "kasong@redhat.com" <kasong@redhat.com>, "bhe@redhat.com" <bhe@redhat.com>, "x86@kernel.org" <x86@kernel.org>, "kexec@lists.infradead.org" <kexec@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Junichi Nomura <j-nomura@ce.jp.nec.com>, Dave Young <dyoung@redhat.com> Subject: Re: [PATCH v2] x86/boot: Use EFI setup data if provided Date: Fri, 29 Mar 2019 17:05:50 +0800 [thread overview] Message-ID: <20190329090550.GI4234@localhost.localdomain> (raw) In-Reply-To: <20190329083920.GA21152@zn.tnic> On Fri, Mar 29, 2019 at 09:39:20AM +0100, Borislav Petkov wrote: >On Fri, Mar 29, 2019 at 03:05:52AM +0000, Junichi Nomura wrote: >> > You don't need that variable and can return "table" or 0 after the endif >> > below. >> >> I could do that but it will slightly change the current logic. >> >> Existing code does this: >> >> if (!(efi_guidcmp(guid, ACPI_TABLE_GUID))) >> rsdp_addr = table; >> else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) >> return table; >> >> I thought it was to return the table for ACPI_20_TABLE_GUID >> if both tables exist. If we remove rsdp_addr, the code will be: >> >> if (!(efi_guidcmp(guid, ACPI_TABLE_GUID))) >> return table; >> else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID))) >> return table; >> >> So if there are 2 tables, we return the one that comes first. >> Is it ok? > >That's a good question. > >Chao, what was the intention there, ACPI_20_TABLE_GUID is the preferred >table to return? If so, why? Yes, ACPI_20_TABLE_GUID is preferred. ACPI_20 means version 2.0 and later versions, ACPI_TABLE_GUID is version 1.0 which is earlier than 2003, it's too old. Version 2.0 has more features than 1.0. Sure the new version is preferred. So many codes prefers ACPI20, such as in drivers/acpi/osl.c where kernel parses RSDP ACPI20 firstly. Documentation/ABI/testing/sysfs-firmware-efi says in /sys/firmware/efi/systab, ACPI20 comes before ACPI. So that kexec-tools code kexec/arch/i386/crashdump-x86.c can easily get ACPI_20(if there is ACPI_20) before ACPI 1.0. But in my code, I am not sure which version will be found firstly, so I write this logical, if ACPI20 found, return directly, then consider ACPI 1.0. Thanks, Chao Fan >-- >Regards/Gruss, > Boris. > >Good mailing practices for 400: avoid top-posting and trim the reply. > > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2019-03-29 9:06 UTC|newest] Thread overview: 173+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-22 11:03 [PATCH] x86/boot: Use EFI setup data if provided Junichi Nomura 2019-03-22 15:23 ` Borislav Petkov 2019-03-25 0:27 ` Junichi Nomura 2019-03-25 0:27 ` Junichi Nomura 2019-03-25 6:01 ` Dave Young 2019-03-25 6:01 ` Dave Young 2019-03-25 6:19 ` Dave Young 2019-03-25 6:19 ` Dave Young 2019-03-25 6:45 ` Kairui Song 2019-03-25 6:45 ` Kairui Song 2019-03-25 6:47 ` Junichi Nomura 2019-03-25 6:47 ` Junichi Nomura 2019-03-25 6:59 ` Dave Young 2019-03-25 6:59 ` Dave Young 2019-03-25 8:27 ` [PATCH v2] " Junichi Nomura 2019-03-25 8:27 ` Junichi Nomura 2019-03-25 8:54 ` Boris Petkov 2019-03-25 8:54 ` Boris Petkov 2019-03-25 9:25 ` [PATCH v2] x86/boot: Don't try to search RSDP from EFI when kexec-booted Junichi Nomura 2019-03-25 9:25 ` Junichi Nomura 2019-03-25 10:15 ` [PATCH v2] x86/boot: Use EFI setup data if provided Dave Young 2019-03-25 10:15 ` Dave Young 2019-03-25 10:36 ` Junichi Nomura 2019-03-25 10:36 ` Junichi Nomura 2019-03-25 11:16 ` Dave Young 2019-03-25 11:16 ` Dave Young 2019-03-25 12:01 ` Borislav Petkov 2019-03-25 12:01 ` Borislav Petkov 2019-03-25 12:23 ` Dave Young 2019-03-25 12:23 ` Dave Young 2019-03-25 12:32 ` Borislav Petkov 2019-03-25 12:32 ` Borislav Petkov 2019-03-25 23:10 ` Junichi Nomura 2019-03-25 23:10 ` Junichi Nomura 2019-03-26 12:46 ` Dave Young 2019-03-26 12:46 ` Dave Young 2019-03-26 13:57 ` Borislav Petkov 2019-03-26 13:57 ` Borislav Petkov 2019-03-27 1:48 ` bhe 2019-03-27 1:48 ` bhe 2019-03-27 12:14 ` Borislav Petkov 2019-03-27 12:14 ` Borislav Petkov 2019-03-28 4:17 ` Junichi Nomura 2019-03-28 4:17 ` Junichi Nomura 2019-03-28 6:26 ` Chao Fan 2019-03-28 6:26 ` Chao Fan 2019-03-28 6:43 ` bhe 2019-03-28 6:43 ` bhe 2019-03-28 7:43 ` Junichi Nomura 2019-03-28 7:43 ` Junichi Nomura 2019-03-28 15:52 ` Borislav Petkov 2019-03-28 15:52 ` Borislav Petkov 2019-03-29 3:05 ` Junichi Nomura 2019-03-29 3:05 ` Junichi Nomura 2019-03-29 8:39 ` Borislav Petkov 2019-03-29 8:39 ` Borislav Petkov 2019-03-29 9:05 ` Chao Fan [this message] 2019-03-29 9:05 ` Chao Fan 2019-03-29 9:16 ` Borislav Petkov 2019-03-29 9:16 ` Borislav Petkov 2019-03-29 9:37 ` Junichi Nomura 2019-03-29 9:37 ` Junichi Nomura 2019-03-29 9:44 ` Chao Fan 2019-03-29 9:44 ` Chao Fan 2019-03-29 9:56 ` Junichi Nomura 2019-03-29 9:56 ` Junichi Nomura 2019-03-29 7:20 ` [PATCH] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Junichi Nomura 2019-03-29 7:20 ` Junichi Nomura 2019-03-29 7:49 ` bhe 2019-03-29 7:49 ` bhe 2019-03-29 8:29 ` Chao Fan 2019-03-29 8:29 ` Chao Fan 2019-03-29 8:39 ` Junichi Nomura 2019-03-29 8:39 ` Junichi Nomura 2019-03-29 9:18 ` Chao Fan 2019-03-29 9:18 ` Chao Fan 2019-03-29 9:16 ` bhe 2019-03-29 9:16 ` bhe 2019-03-29 9:20 ` Chao Fan 2019-03-29 9:20 ` Chao Fan 2019-04-01 0:08 ` [PATCH v2] " Junichi Nomura 2019-04-01 0:08 ` Junichi Nomura 2019-04-02 9:41 ` Chao Fan 2019-04-02 9:41 ` Chao Fan 2019-04-02 9:53 ` Junichi Nomura 2019-04-02 9:53 ` Junichi Nomura 2019-04-02 11:06 ` Chao Fan 2019-04-02 11:06 ` Chao Fan 2019-04-02 10:22 ` Junichi Nomura 2019-04-02 10:22 ` Junichi Nomura 2019-04-02 12:03 ` Dave Young 2019-04-02 12:03 ` Dave Young 2019-04-03 5:35 ` Chao Fan 2019-04-03 5:35 ` Chao Fan 2019-04-03 5:53 ` Dave Young 2019-04-03 5:53 ` Dave Young 2019-04-03 6:39 ` Dave Young 2019-04-03 6:39 ` Dave Young 2019-04-03 7:30 ` Chao Fan 2019-04-03 7:30 ` Chao Fan 2019-04-03 7:50 ` bhe 2019-04-03 7:50 ` bhe 2019-04-03 8:23 ` Dave Young 2019-04-03 8:23 ` Dave Young 2019-04-03 8:26 ` Dave Young 2019-04-03 8:26 ` Dave Young 2019-04-03 16:14 ` Borislav Petkov 2019-04-03 16:14 ` Borislav Petkov 2019-04-04 1:02 ` Chao Fan 2019-04-04 1:02 ` Chao Fan 2019-04-03 9:28 ` Chao Fan 2019-04-03 9:28 ` Chao Fan 2019-04-03 7:21 ` Chao Fan 2019-04-03 7:21 ` Chao Fan 2019-04-03 8:09 ` Dave Young 2019-04-03 8:09 ` Dave Young 2019-04-03 8:23 ` Chao Fan 2019-04-03 8:23 ` Chao Fan 2019-04-03 9:02 ` Chao Fan 2019-04-03 9:02 ` Chao Fan 2019-04-03 9:39 ` Chao Fan 2019-04-03 9:39 ` Chao Fan 2019-04-04 1:23 ` Junichi Nomura 2019-04-04 1:23 ` Junichi Nomura 2019-04-04 2:52 ` Dave Young 2019-04-04 2:52 ` Dave Young 2019-04-04 3:00 ` bhe 2019-04-04 3:00 ` bhe 2019-04-04 3:10 ` bhe 2019-04-04 3:10 ` bhe 2019-04-04 3:22 ` Dave Young 2019-04-04 3:22 ` Dave Young 2019-04-04 6:41 ` Dave Young 2019-04-04 6:41 ` Dave Young 2019-04-04 7:20 ` Chao Fan 2019-04-04 7:20 ` Chao Fan 2019-04-04 7:41 ` Dave Young 2019-04-04 7:41 ` Dave Young 2019-04-04 7:48 ` Chao Fan 2019-04-04 7:48 ` Chao Fan 2019-04-04 12:22 ` Borislav Petkov 2019-04-04 12:22 ` Borislav Petkov 2019-04-04 14:08 ` Dave Young 2019-04-04 14:08 ` Dave Young 2019-04-03 8:18 ` Dave Young 2019-04-03 8:18 ` Dave Young 2019-04-02 10:25 ` [PATCH v3] " Junichi Nomura 2019-04-02 10:25 ` Junichi Nomura 2019-04-04 7:32 ` Dave Young 2019-04-04 7:32 ` Dave Young 2019-04-04 12:24 ` Borislav Petkov 2019-04-04 12:24 ` Borislav Petkov 2019-04-04 14:12 ` Dave Young 2019-04-04 14:12 ` Dave Young 2019-04-04 14:41 ` Borislav Petkov 2019-04-04 14:41 ` Borislav Petkov 2019-04-05 1:36 ` Dave Young 2019-04-05 1:36 ` Dave Young 2019-04-05 4:19 ` Junichi Nomura 2019-04-05 4:19 ` Junichi Nomura 2019-03-28 23:11 ` [PATCH v2] x86/boot: Use EFI setup data if provided bhe 2019-03-28 23:11 ` bhe 2019-03-29 3:34 ` Junichi Nomura 2019-03-29 3:34 ` Junichi Nomura 2019-03-29 3:52 ` bhe 2019-03-29 3:52 ` bhe 2019-03-29 5:16 ` Junichi Nomura 2019-03-29 5:16 ` Junichi Nomura 2019-03-25 7:27 ` [PATCH] " Baoquan He 2019-03-25 7:53 ` Borislav Petkov 2019-03-25 8:21 ` Baoquan He 2019-03-25 8:43 ` Thomas Gleixner 2019-03-25 9:03 ` Baoquan He
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