From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 988277D414; Mon, 8 Apr 2024 13:22:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712582541; cv=none; b=P9WdqmLB1KPjvo5D7uDQjxVArY+CmZcqihgJ6ILQs0wxvpQlGxDikHBp6h2UT6FXnhf9Ju/Ah/GgxLU+o7pRxvMyWFOcsdX1l7tFqgly7Ou0bWeOtvKytPG+m9v7LkfAU62qUgmz3LTy7IVf6SMlYzNFLWSL3TVE2iInFG4nyzo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712582541; c=relaxed/simple; bh=5IVWqescEom279QvPJ+i6gInNZC4mVGVT1bEm+9fqs4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CL+MJ57F3aZQV6etzv9vo8aJ+478fYegOWT0Xumo4SSyWqzYw3nv5yYP3kgyuasAYe+je9FFrL8Cnkw4yjh1+4cpSO6MLgk7fVq07a74Hln/fdSfJj0Uzl5Phksll3iiO063q3/p4gza1z1c5yP8fSbpeIWVl7lEQQjf0A6WYqU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=omUo4NKF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="omUo4NKF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C5DBC433C7; Mon, 8 Apr 2024 13:22:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712582541; bh=5IVWqescEom279QvPJ+i6gInNZC4mVGVT1bEm+9fqs4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=omUo4NKF0Rbmdr9zki/pjDFFrixlW8spBi/heE852wpzMiAmbrv3rKOTxD4wt164x VUf6CGtV/F6jdOoaJBZW3jIUaSGZVABFFL8zxqsFfxz3JPeMIjOAyYwGRHTzOWElJ4 VyG9+DIZ8VugBjtc4aHgKcOTz5zlzDxaxhustg/I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, kernel test robot , "Borislav Petkov (AMD)" , Linus Torvalds Subject: [PATCH 6.6 101/252] x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO Date: Mon, 8 Apr 2024 14:56:40 +0200 Message-ID: <20240408125309.781930124@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240408125306.643546457@linuxfoundation.org> References: <20240408125306.643546457@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Borislav Petkov (AMD) commit 0e110732473e14d6520e49d75d2c88ef7d46fe67 upstream. The srso_alias_untrain_ret() dummy thunk in the !CONFIG_MITIGATION_SRSO case is there only for the altenative in CALL_UNTRAIN_RET to have a symbol to resolve. However, testing with kernels which don't have CONFIG_MITIGATION_SRSO enabled, leads to the warning in patch_return() to fire: missing return thunk: srso_alias_untrain_ret+0x0/0x10-0x0: eb 0e 66 66 2e WARNING: CPU: 0 PID: 0 at arch/x86/kernel/alternative.c:826 apply_returns (arch/x86/kernel/alternative.c:826 Put in a plain "ret" there so that gcc doesn't put a return thunk in in its place which special and gets checked. In addition: ERROR: modpost: "srso_alias_untrain_ret" [arch/x86/kvm/kvm-amd.ko] undefined! make[2]: *** [scripts/Makefile.modpost:145: Module.symvers] Chyba 1 make[1]: *** [/usr/src/linux-6.8.3/Makefile:1873: modpost] Chyba 2 make: *** [Makefile:240: __sub-make] Chyba 2 since !SRSO builds would use the dummy return thunk as reported by petr.pisar@atlas.cz, https://bugzilla.kernel.org/show_bug.cgi?id=218679. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202404020901.da75a60f-oliver.sang@intel.com Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/all/202404020901.da75a60f-oliver.sang@intel.com/ Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/lib/retpoline.S | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -222,8 +222,11 @@ SYM_CODE_END(srso_return_thunk) #define JMP_SRSO_UNTRAIN_RET "ud2" /* Dummy for the alternative in CALL_UNTRAIN_RET. */ SYM_CODE_START(srso_alias_untrain_ret) - RET + ANNOTATE_UNRET_SAFE + ret + int3 SYM_FUNC_END(srso_alias_untrain_ret) +__EXPORT_THUNK(srso_alias_untrain_ret) #endif /* CONFIG_CPU_SRSO */ #ifdef CONFIG_CPU_UNRET_ENTRY