From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x224+twDk4kfbqDG8x0T0X9HKPvDXI3x1DHSBWFyFEengZV6O3C3OIaj5wfk6LHSbDaTzwxS1 ARC-Seal: i=1; a=rsa-sha256; t=1517950380; cv=none; d=google.com; s=arc-20160816; b=lgXIbVH0LSZuoKZn5tWAwShAjayuLi4+zL9jd6mHH7oey7tSNu8fcdHl6SRDV53UYj 442JKo/L4HB5YVQ77t6rOgEQcVmmQRnAkFoJjuL36Q9YoLmjjIE664hcxqgj8n1wUEm8 3dObX6q8x65x2apV5YgbdFAhnrbeS5xQVxe7hUW+iEMfwJQkLcLP8t1yhQPTUkx4IMYV Be6IO6qjrYr9I0fq9POvToxm3y5Uvi9qacR3ezuBoVb/aQ1M19Fv2xoUh5gMxE4v2anI RxTd+5qAcLTekTNw4qx3KUNF9uRfYNWBx5goGwgmH+XvmcB+X+ORoR+ZjmL11gunafW5 nFlg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:date:face:references:in-reply-to:cc:to:from:subject :message-id:dkim-signature:arc-authentication-results; bh=qSyWeN0m84AAgokJWdEeIBPp0skHKxauGBo1my6mYcw=; b=FdO3SzBVFY45oSRsD8IzsxKcwxLPLgchGlfnh9VGBN/NFOjZKFvvF3/zhFxibCLjgx ApZ6ifhJYWI3uvidxQP/xHEqoruLY7v7GVyhmavQob9bif+V5VdXmSOadXhEUDhrhgQw iomVAuH3R9OH+VgWfelKPN4Jza/Gyhf78UkZaMxqFKDXwiLaB9ScYuykLpwdXg16IBIN w4e3sU4mtEnoq/u0EV1DvzupK4Uxjkh7dkoqTO8ZkC+t7sNC/sFD+38U2iJV0xUpIknI ye1T+y9kM/Ryhsax4TJCALFAUIMhsO4vOv7Pk8pBTvNCbOIgB4+yxFEJMIchuWaMeIp1 XGKw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@woodhou.se header.s=twosheds.20170209 header.b=cmEgFbRT; spf=neutral (google.com: 2001:8b0:10b:1:21d:7dff:fe04:dbe2 is neither permitted nor denied by best guess record for domain of david@woodhou.se) smtp.mailfrom=david@woodhou.se Authentication-Results: mx.google.com; dkim=pass header.i=@woodhou.se header.s=twosheds.20170209 header.b=cmEgFbRT; spf=neutral (google.com: 2001:8b0:10b:1:21d:7dff:fe04:dbe2 is neither permitted nor denied by best guess record for domain of david@woodhou.se) smtp.mailfrom=david@woodhou.se Message-ID: <1517950341.3677.27.camel@woodhou.se> Subject: Re: [RFC] x86/retpoline: Add clang support for 64-bit builds From: David Woodhouse To: Guenter Roeck , Thomas Gleixner Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , gnomes@lxorguk.ukuu.org.uk, Rik van Riel , Andi Kleen , Josh Poimboeuf , thomas.lendacky@amd.com, Peter Zijlstra , Linus Torvalds , Jiri Kosina , Andy Lutomirski , Dave Hansen , Kees Cook , Tim Chen , Greg Kroah-Hartman , Paul Turner In-Reply-To: <20180206203218.GA11026@roeck-us.net> References: <1517614240-31269-1-git-send-email-linux@roeck-us.net> <20180206203218.GA11026@roeck-us.net> Face: 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 Content-Type: multipart/signed; micalg="sha-256"; protocol="application/x-pkcs7-signature"; boundary="=-bGSWtZKA9dRumKOPehNB" Date: Tue, 06 Feb 2018 20:52:21 +0000 Mime-Version: 1.0 X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1591333873946801262?= X-GMAIL-MSGID: =?utf-8?q?1591686337975160757?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: --=-bGSWtZKA9dRumKOPehNB Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2018-02-06 at 12:32 -0800, Guenter Roeck wrote: >=20 > >=C2=A0 > Feedback, anyone ? >=20 > I understand that there is no love for the ABI differences between clang > and gcc, but that doesn't help me. Even if the patch is unacceptable > as-is, I would like to have some feedback to get an idea if I am on the > right track, and what I would have to change to at least move into the > right direction. I'm going for just a comprehensive NACK. If they fix clang so that at least the thunk symbols __x86_indirect_thunk_\reg are compatible, then we could tolerate command line differences. Otherwise, just no. Unless you really fancy trying to do some kind of alias hack in modules so that they link to the external thunk by its proper name, even when built with clang? I reserve the right to hate that too. --=-bGSWtZKA9dRumKOPehNB Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCEEow ggUsMIIEFKADAgECAhEA9ZDpDf4kaqsgeKPMYkVQ6TANBgkqhkiG9w0BAQsFADCBlzELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgG A1UEChMRQ09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhl bnRpY2F0aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0EwHhcNMTcxMjIxMDAwMDAwWhcNMTgxMjIxMjM1 OTU5WjAhMR8wHQYJKoZIhvcNAQkBFhBkYXZpZEB3b29kaG91LnNlMIIBIjANBgkqhkiG9w0BAQEF AAOCAQ8AMIIBCgKCAQEAsBVjYH5kFEalYHmtKg/8hdcqSItn6OthZem3CrU0/he9fK6DMfXw8z+i BmYW+N5AirTPpwcufTLhJtp/B/ntuLVHf/rSJcHy7na2Ok26y1zayaua4Z210rhtxe4ptLThTDtm iOTDnt/gCxiLJSZTC973kojSJs0swj1CSHnDLmLfVW7uJR9Zi91sVKrXfyY+AeAGBnRqbeYOx/xd nwPh1sjMB6PKhxbGx37NE9cSD7MEgPn+fUh7UHRwlMQNFCl3TxTxMm/Uqc/P+edJGsROHwct6zza 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