From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7059425EFAE for ; Wed, 3 Dec 2025 21:29:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764797344; cv=none; b=FtuMAfkh9fR+ULDQeUZCh0XWa0CSVkYNK1J6ESyMbtruoeVTW/qwqE/jHFbB5kYYlblZuakpEyLTgyZkMNMTek8oypZy5d3cdJ6YLzTotW1OxTHi6YYjkhhG5sQ/V6gXGk9UQPzcAq8kXGc9a2cfMQDUrurMJKF0kcPzxqs29z4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764797344; c=relaxed/simple; bh=POcPTOvSs+M3fRkWppI85qlGsNA/0MHyCOCJXvM3jC0=; h=Content-Type:Message-ID:Date:MIME-Version:Subject:From:To:Cc: References:In-Reply-To; b=UJ+CdXE2IkkxSsW05Ye+OI5++98PqffWeGTIKs/DwwcO+/Yde2TfNDTguK8jIZpo2KFjTSzou1an8KqL8VO+TEx8/m+1GzLa+i9d7UGBOBWcCJfjpQ8EWqQXElKQOokRvWp7QB0ScTn6gmLEG6P/8WU8dT5JLV1kri5rQbAxc+8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=f6jeM4jp; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="f6jeM4jp" Received: from [172.27.2.41] (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 5B3LRebl2612389 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Wed, 3 Dec 2025 13:28:30 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 5B3LRebl2612389 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025112201; t=1764797311; bh=mLUzlJfiW249HdTyKiGIuAleFq2oi4ggIg0BsRe1U0s=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=f6jeM4jpCxVKG6iJAMsosrykPXAUK2zDXn4IYr4csRPUKJ28a79I5URIZYqq1ZBD6 +W5qIrQBq8TT/1CRsous1LF1BndkfYwHlKbxPHAciV40QmZBz66T9djORYSEN0tX83 8gw5aC3aFAK/0hG2qBSmLPIXpHZ7RxvmWVENsbU/V5udxRHfsJZXMiTvE8VoJr4gQB +1yLvWTTQ6kiZ7mKhkV8CPQdvPlCEh+GXleUY6Hi019iUjyJ2ifMpKqPG70Xz7ux+A 2qD75TkYvrjTlqYHt6yRJ+RIAAbg7tIwHNamb92yc4OWNtCh2HFf08zmUHaTZMfYDh HYshGg2qPqIRg== Content-Type: multipart/mixed; boundary="------------4ykVdBoEwmiYxVrkWXX0RayN" Message-ID: <05db807e-887a-4502-8de1-ec9910f66b60@zytor.com> Date: Wed, 3 Dec 2025 13:27:40 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] x86: fix oops caused by old EFI info on kexec boot From: "H. Peter Anvin" To: Ingo Molnar , James Le Cuirot Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Ard Biesheuvel References: <20251126173209.374755-2-chewi@gentoo.org> <76520AF9-9A09-4D9C-850F-04761E1C1484@zytor.com> Content-Language: en-US, sv-SE In-Reply-To: <76520AF9-9A09-4D9C-850F-04761E1C1484@zytor.com> This is a multi-part message in MIME format. --------------4ykVdBoEwmiYxVrkWXX0RayN Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2025-12-03 12:59, H. Peter Anvin wrote: >> >> Yeah, so this looks like a good fix - but please let's >> introduce some sort of enum for the bootloader IDs >> in arch/x86/include/uapi/asm/bootparam.h, I had to search >> way too long to figure out what 0xD is and where it >> was defined :-) >> >> Also, please introduce a "x86_bootloader_is_kexec()" kind >> of helper inline function as well. >> > > An enum and an accessor, please, that decodes the extended ID if necessary. > Maybe something like this (untested.) -hpa --------------4ykVdBoEwmiYxVrkWXX0RayN Content-Type: text/x-patch; charset=UTF-8; name="0001-x86-boot-add-enumeration-and-accessors-for-boot-load.patch" Content-Disposition: attachment; filename*0="0001-x86-boot-add-enumeration-and-accessors-for-boot-load.pa"; filename*1="tch" Content-Transfer-Encoding: base64 RnJvbSBiNjVhMjdiMDA5NmJkOTUzZjU2ZmFjZWU3YzQxMjEzYmNlNWNiMTNlIE1vbiBTZXAg MTcgMDA6MDA6MDAgMjAwMQpGcm9tOiAiSC4gUGV0ZXIgQW52aW4iIDxocGFAenl0b3IuY29t PgpEYXRlOiBXZWQsIDMgRGVjIDIwMjUgMTM6MjA6MDcgLTA4MDAKU3ViamVjdDogW1BBVENI IDEvMV0geDg2L2Jvb3Q6IGFkZCBlbnVtZXJhdGlvbiBhbmQgYWNjZXNzb3JzIGZvciBib290 IGxvYWRlcgogSUQgYW5kIHZlcnNpb24KCkFkZCBhbiBlbnVtZXJhdGlvbiBvZiBib290IGxv YWRlciB0eXBlIElEczsgc2luY2UgYm90aCB0aGUgdHlwZSBJRCBhbmQKdGhlIHZlcnNpb24g bnVtYmVyIGlzIHNwbGl0IGJldHdlZW4gdHdvIGZpZWxkcywgYWRkIGFjY2Vzc29ycyB0byBy ZWFkCmFuZCB3cml0ZSB0aGVzZSBmaWVsZHMgKHRoZSBsYXR0ZXIgaXMgaW50ZW5kZWQgZm9y IGJvb3QgbG9hZGVycyB0byB1c2UKYXMgdGhpcyBpcyBhIHVhcGkgaGVhZGVyLikKClNpZ25l ZC1vZmYtYnk6IEguIFBldGVyIEFudmluIChJbnRlbCkgPGhwYUB6eXRvci5jb20+Ci0tLQog YXJjaC94ODYvaW5jbHVkZS91YXBpL2FzbS9ib290cGFyYW0uaCB8IDQ0ICsrKysrKysrKysr KysrKysrKysrKysrKysrKwogMSBmaWxlIGNoYW5nZWQsIDQ0IGluc2VydGlvbnMoKykKCmRp ZmYgLS1naXQgYS9hcmNoL3g4Ni9pbmNsdWRlL3VhcGkvYXNtL2Jvb3RwYXJhbS5oIGIvYXJj aC94ODYvaW5jbHVkZS91YXBpL2FzbS9ib290cGFyYW0uaAppbmRleCBkYWZiZjU4MWM1MTUu LjM4Zjk4MDEyZmQyYiAxMDA2NDQKLS0tIGEvYXJjaC94ODYvaW5jbHVkZS91YXBpL2FzbS9i b290cGFyYW0uaAorKysgYi9hcmNoL3g4Ni9pbmNsdWRlL3VhcGkvYXNtL2Jvb3RwYXJhbS5o CkBAIC0yNiw2ICsyNiwyOCBAQAogI2RlZmluZSBYTEZfNUxFVkVMX0VOQUJMRUQJCSgxPDw2 KQogI2RlZmluZSBYTEZfTUVNX0VOQ1JZUFRJT04JCSgxPDw3KQogCisvKiBib290bG9hZGVy IElEICovCisjZGVmaW5lIEJPT1RMT0FERVJfTElMTwkJMHgwMAorI2RlZmluZSBCT09UTE9B REVSX0xPQURMSU4JMHgwMQorLyogMHgwMiB1c2VkIGJ5IGtlcm5lbCBpbnRlcm5hbCBib290 IHNlY3RvciAtIGxvbmcgc2luY2Ugb2Jzb2xldGUgKi8KKyNkZWZpbmUgQk9PVExPQURFUl9T WVNMSU5VWAkweDAzCisjZGVmaW5lIEJPT1RMT0FERVJfSVBYRQkJMHgwNAorI2RlZmluZSBC T09UTE9BREVSX0VMSUxPCTB4MDUKKy8qIDB4MDYgdW5rbm93biB1c2VyICovCisjZGVmaW5l IEJPT1RMT0FERVJfR1JVQgkJMHgwNworI2RlZmluZSBCT09UTE9BREVSX1VCT09UCTB4MDgK KyNkZWZpbmUgQk9PVExPQURFUl9YRU4JCTB4MDkKKyNkZWZpbmUgQk9PVExPQURFUl9HVUpJ TgkweDBhCisjZGVmaW5lIEJPT1RMT0FERVJfUUVNVQkJMHgwYgorI2RlZmluZSBCT09UTE9B REVSX0FSQ1RVUlVTCTB4MGMJLyogIkFyY3R1cnVzIE5ldHdvcmtzIHVDYm9vdGxvYWRlciIg Ki8KKyNkZWZpbmUgQk9PVExPQURFUl9LRVhFQ19UT09MUwkweDBkCisjZGVmaW5lIEJPT1RM T0FERVJfRVhURU5ERURfSUQJMHgwZQkvKiBFc2NhcGUgaW50byB0aGUgMHgxMCsgc3BhY2Ug Ki8KKyNkZWZpbmUgQk9PVExPQURFUl9NSVNTSU5HX0lECTB4MGYJLyogQm9vdGxvYWRlciB1 bmtub3duICovCisjZGVmaW5lIEJPT1RMT0FERVJfRVhUSURfQkFTRQkweDEwCS8qIEVycm9y OiBleHRfbG9hZGVyX3R5cGUgbmV2ZXIgc2V0ICovCisjZGVmaW5lIEJPT1RMT0FERVJfTUlO SU1BTAkweDExCS8qICJNaW5pbWFsIExpbnV4IEJvb3Rsb2FkZXIiICovCisjZGVmaW5lIEJP T1RMT0FERVJfT1ZNRgkJMHgxMgorI2RlZmluZSBCT09UTE9BREVSX0JBUkVCT1gJMHgxMwor CiAjaWZuZGVmIF9fQVNTRU1CTEVSX18KIAogI2luY2x1ZGUgPGxpbnV4L3R5cGVzLmg+CkBA IC0xNjIsNiArMTg0LDI4IEBAIHN0cnVjdCBib290X3BhcmFtcyB7CiAJX191OCAgX3BhZDlb Mjc2XTsJCQkJLyogMHhlZWMgKi8KIH0gX19hdHRyaWJ1dGVfXygocGFja2VkKSk7CiAKK3N0 YXRpYyBpbmxpbmUgdW5zaWduZWQgaW50IGJvb3RfbG9hZGVyX3R5cGUoY29uc3Qgc3RydWN0 IGJvb3RfcGFyYW1zICpfYnApCit7CisJdW5zaWduZWQgaW50IF90eXBlID0gX2JwLT50eXBl X29mX2xvYWRlciA+PiA0OworCWlmIChfdHlwZSA9PSBCT09UTE9BREVSX0VYVEVOREVEX0lE KQorCQlfdHlwZSA9IF9icC0+ZXh0X2xvYWRlcl90eXBlICsgQk9PVExPQURFUl9FWFRJRF9C QVNFCisJcmV0dXJuIF90eXBlOworfQorc3RhdGljIGlubGluZSB1bnNpZ25lZCBpbnQgYm9v dF9sb2FkZXJfdmVyKGNvbnN0IHN0cnVjdCBib290X3BhcmFtcyAqX2JwKQoreworCXJldHVy biAoX2JwLT50eXBlX29mX2xvYWRlciAmIDB4MGYpICsgKF9icC0+ZXh0X2xvYWRlcl92ZXIg PDwgNCk7Cit9CitzdGF0aWMgaW5saW5lIHZvaWQgc2V0X2Jvb3RfbG9hZGVyKHN0cnVjdCBi b290X3BhcmFtcyAqX2JwLAorCQkJCSAgIHVuc2lnbmVkIGludCBfdHlwZSwgdW5zaWduZWQg aW50IF92ZXIpCit7CisJaWYgKF90eXBlID49IEJPT1RMT0FERVJfRVhUSURfQkFTRSkgewor CQlfYnAtPmV4dF9sb2FkZXJfdHlwZSA9IF90eXBlIC0gQk9PVExPQURFUl9FWFRJRF9CQVNF OworCQlfdHlwZSA9IEJPT1RMT0FERVJfRVhURU5ERURfSUQ7CisJfQorCV9icC0+ZXh0X2xv YWRlcl92ZXIgPSBfdmVyID4+IDQ7CisJX2JwLT50eXBlX29mX2xvYWRlciA9IF90eXBlICsg KF92ZXIgJiAweDBmKTsKK30KKwogLyoqCiAgKiBlbnVtIHg4Nl9oYXJkd2FyZV9zdWJhcmNo IC0geDg2IGhhcmR3YXJlIHN1YmFyY2hpdGVjdHVyZQogICoKLS0gCjIuNTIuMAoK --------------4ykVdBoEwmiYxVrkWXX0RayN--