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 2E1403D74 for ; Mon, 21 Nov 2022 12:44:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71E54C433C1; Mon, 21 Nov 2022 12:44:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669034680; bh=YGfTrH/XCYdAcmvlSU3rPMRSaVp9GxTpcu0loJ9SueA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PM6belHAwwcUKBtEMJFwNtOLx50w68A5NDu8ZLMZKrab9IIDiOSu0Tr0tDwhGVUAU DUIQkOAtSCAoernj5rZFqspBNmiGLHafAucgg8TWYchprcvUkdk6oClbOi9ADeo8p9 b+m20zh5tXkRsnnwlKMAEgjcAT1O+BW11E/NNUGE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Peter Zijlstra (Intel)" , Alexandre Chartre , Josh Poimboeuf , Thadeu Lima de Souza Cascardo , Suleiman Souhlal Subject: [PATCH 4.19 19/34] x86/speculation: Change FILL_RETURN_BUFFER to work with objtool Date: Mon, 21 Nov 2022 13:43:41 +0100 Message-Id: <20221121124151.578607852@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221121124150.886779344@linuxfoundation.org> References: <20221121124150.886779344@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 089dd8e53126ebaf506e2dc0bf89d652c36bfc12 upstream. Change FILL_RETURN_BUFFER so that objtool groks it and can generate correct ORC unwind information. - Since ORC is alternative invariant; that is, all alternatives should have the same ORC entries, the __FILL_RETURN_BUFFER body can not be part of an alternative. Therefore, move it out of the alternative and keep the alternative as a sort of jump_label around it. - Use the ANNOTATE_INTRA_FUNCTION_CALL annotation to white-list these 'funny' call instructions to nowhere. - Use UNWIND_HINT_EMPTY to 'fill' the speculation traps, otherwise objtool will consider them unreachable. - Move the RSP adjustment into the loop, such that the loop has a deterministic stack layout. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Alexandre Chartre Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200428191700.032079304@infradead.org [cascardo: fixup because of backport of ba6e31af2be96c4d0536f2152ed6f7b6c11bca47 ("x86/speculation: Add LFENCE to RSB fill sequence")] [cascardo: no intra-function call validation support] [cascardo: avoid UNWIND_HINT_EMPTY because of svm] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Suleiman Souhlal Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/nospec-branch.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -4,11 +4,13 @@ #define _ASM_X86_NOSPEC_BRANCH_H_ #include +#include #include #include #include #include +#include /* * Fill the CPU return stack buffer. @@ -51,9 +53,9 @@ lfence; \ jmp 775b; \ 774: \ + add $(BITS_PER_LONG/8) * 2, sp; \ dec reg; \ jnz 771b; \ - add $(BITS_PER_LONG/8) * nr, sp; \ /* barrier for jnz misprediction */ \ lfence; #else @@ -158,10 +160,8 @@ */ .macro FILL_RETURN_BUFFER reg:req nr:req ftr:req #ifdef CONFIG_RETPOLINE - ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE "jmp .Lskip_rsb_\@", \ - __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \ - \ftr + ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr + __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP) .Lskip_rsb_\@: #endif .endm