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 267DC1171A for ; Mon, 21 Aug 2023 20:04:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F741C433C7; Mon, 21 Aug 2023 20:04:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1692648270; bh=3dYGAnblenh4Y2E+cwX51+O6lBE64mmpDobJP0Efh9k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oMPqxwdPFR2XArX0y4oeLZci9mPWp7+x35G+d9O8kKtvUaBxQYI8lnG5PdhngcXe8 JMy0KOHkhMjX84y3PaiagK1qhgXL6E8S8kbRd69bgo51guM1GkBZzGZMo9OUBidt6e 5y9uW0dmVgBCGljG6fr/sNLMgN9W2+Sm47u5ExcI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Peter Zijlstra (Intel)" , "Borislav Petkov (AMD)" Subject: [PATCH 6.4 115/234] x86/cpu: Fix up srso_safe_ret() and __x86_return_thunk() Date: Mon, 21 Aug 2023 21:41:18 +0200 Message-ID: <20230821194133.907852017@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230821194128.754601642@linuxfoundation.org> References: <20230821194128.754601642@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Peter Zijlstra commit af023ef335f13c8b579298fc432daeef609a9e60 upstream. vmlinux.o: warning: objtool: srso_untrain_ret() falls through to next function __x86_return_skl() vmlinux.o: warning: objtool: __x86_return_thunk() falls through to next function __x86_return_skl() This is because these functions (can) end with CALL, which objtool does not consider a terminating instruction. Therefore, replace the INT3 instruction (which is a non-fatal trap) with UD2 (which is a fatal-trap). This indicates execution will not continue past this point. Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230814121148.637802730@infradead.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/lib/retpoline.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -259,7 +259,7 @@ SYM_INNER_LABEL(srso_safe_ret, SYM_L_GLO int3 lfence call srso_safe_ret - int3 + ud2 SYM_CODE_END(srso_safe_ret) SYM_FUNC_END(srso_untrain_ret) __EXPORT_THUNK(srso_untrain_ret) @@ -269,7 +269,7 @@ SYM_CODE_START(__x86_return_thunk) ANNOTATE_NOENDBR ALTERNATIVE_2 "jmp __ret", "call srso_safe_ret", X86_FEATURE_SRSO, \ "call srso_safe_ret_alias", X86_FEATURE_SRSO_ALIAS - int3 + ud2 SYM_CODE_END(__x86_return_thunk) EXPORT_SYMBOL(__x86_return_thunk)