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 AFEE33D9054; Thu, 23 Apr 2026 04:04:47 +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=1776917087; cv=none; b=UjzqRi7TPOkRchuXlI/V9NXY2wcfAUWEOCH/ynA+45b/meOW+QqiCyv0cEH41quqNTjarbfovS8FoA1nL4RlWfwVFiw8OzwdTPAabQBz+L3kbXy5Zprh7RztxxX/I17G46bK7IFouVNXZagyoGSIn06tMChd+SRR0Bvz4KlXiG8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776917087; c=relaxed/simple; bh=jmH/VKCty/iodGaVUHV5BrqXJdFzVyb8Cmk8zWijg8w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AEecHfP9qTKvKJDiSMRkhLYlYbYMuzxBXRMBu7RzW/XH8Vcdpg9GtAAOmn8GkhXL03s1hPBOq8+yebk3aF/UahcjQ/kepf/29p4fV9TnIs+2B1M/lUu6Ex5jWmwQFOtPojVhillHQq0Yu6NU1GX98f6A1JgX+mCt/MZnjctpgYo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YsFbKer+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YsFbKer+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EE20C2BCB2; Thu, 23 Apr 2026 04:04:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776917087; bh=jmH/VKCty/iodGaVUHV5BrqXJdFzVyb8Cmk8zWijg8w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YsFbKer+mw5YiGBPTDk47cFunDmnrwF8xmy4Yevn6it73xihNSdI7/IRoHFPjFpbc iU9MieBK5xCg0G9phrOvyVmdgQP9UflP45Z/wVXoYMBuEeD44t+opS/pIcS67X6OZT Z1kW/IIyJVGQSfIrA9oUIgVfi9XXzuCEmIHtBTgOJ84ojq/nb46OxR7ZKK6EK2G4+b TMkdqE0W0H6jcC0/mbQ1lFQpt8kDwEuLnHf0qJ92fXWERviawR9hY/YPURl6KDTQrN GCI9zzplzQh023ILGrg1uXzt8e3VcptGI41bRYQz2OIXYWNngqRGVBXUwNfmxBQUKW k8GqZ0jvPDd4g== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Peter Zijlstra , Joe Lawrence , Song Liu , Miroslav Benes , Petr Mladek Subject: [PATCH 45/48] x86/Kconfig: Enable CONFIG_PREFIX_SYMBOLS for FineIBT Date: Wed, 22 Apr 2026 21:04:13 -0700 Message-ID: <70107aab81b01f8a2360f052ff550a9e97c30f79.1776916871.git.jpoimboe@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit PREFIX_SYMBOLS has a !CFI dependency because the compiler already generates __cfi_ prefix symbols for kCFI builds, so objtool-generated __pfx_ symbols were considered redundant. However, the __cfi_ symbols only cover the 5-byte kCFI type hash. With FUNCTION_CALL_PADDING, there are also 11 bytes of NOP padding between the hash and the function entry which have no symbol to claim them. The NOPs can be rewritten with call depth tracking thunks at runtime. Without a symbol, unwinders and other tools that symbolize code locations misattribute those bytes. Remove the !CFI guard so objtool creates __pfx_ symbols for all CALL_PADDING configs, covering the full padding area regardless of whether there's also a __cfi_ symbol. Signed-off-by: Josh Poimboeuf --- arch/x86/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f3f7cb01d69d..493b0038ac8d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2439,7 +2439,7 @@ config CALL_THUNKS config PREFIX_SYMBOLS def_bool y - depends on CALL_PADDING && !CFI + depends on CALL_PADDING menuconfig CPU_MITIGATIONS bool "Mitigations for CPU vulnerabilities" -- 2.53.0