From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (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 BDDB12D7DEB; Wed, 29 Oct 2025 14:37:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761748671; cv=none; b=dmkgDHGkrMOxD0gkn73LGBmdwTim1MnjPMOBQJysxeSNTXq4PeX59wHfV08AZuoDdc0J8gVFbaYwW/0qnCzKyGkDufRptxgWLU0knR8OjV15KgQjt7+iY9kTQVJDaHI3ZzSvBbtsokieJM8R9uPAhu35jSVz3D/ApIFz/r2rdd0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761748671; c=relaxed/simple; bh=M6eQkyRoGDKASEZmAd4hIUYpXaAhuwyswirLGyRxIHg=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=kStpHRHH7L8uotTFiOhyjexuUyDHfT9cljzrM78hOJCwFZajZGvFHIl55rPQ+4IwiHi76JLOZ5plpZ7jClOzbIMS08xcjeFFVSz7+yAjdxs4j2RdU2DcxRi6BF2LjdesGH4mBd/+PsxTC2p8uoS7ECRLgvrkHShHBNsxHKA6YO4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=fail (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=JzV5Lfwn reason="signature verification failed"; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="JzV5Lfwn" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 59TEaGje2114125 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Wed, 29 Oct 2025 07:36:17 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 59TEaGje2114125 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025102301; t=1761748578; bh=QGcswXRVbhQ1LyEBlNcfoiqv+Nc2O8kRex4L8HOu5WM=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=JzV5LfwnaN3YZoFEcXJk0aEuwVs0R3X1Jp6aHvdg9ZA4jAWacYgpv5erHYC8fGgNz qM8H9VJj1Eu/OZ1kncOGWS8TjnPZ/acfmL6StOoysolsmfax3vxC6ilFAfkGh42AoH jKURrsIkh/da3GgaUpXxxNBWQnDJJlVEx5gb3GcDEl28Z9oM/7Sag9QUUixtWPhZAs NEELTtRrsbxx1GdoudZogM4z2TBbUWVGsqwFz1kMB8I8SMjJPDdhU4NysyIPkjVlFa Nc6LoiVA5GI2RnRf/WVHZ4t884R2kX6+PYN5cKbVg4Fr5OAoyHMxkVcDe3WIrhNb+U 3o/zm49rbPppA== Date: Wed, 29 Oct 2025 07:36:17 -0700 From: "H. Peter Anvin" To: Brian Gerst CC: "Jason A. Donenfeld" , "Peter Zijlstra (Intel)" , "Theodore Ts'o" , =?ISO-8859-1?Q?Thomas_Wei=DFschuh?= , Xin Li , Andrew Cooper , Andy Lutomirski , Ard Biesheuvel , Borislav Petkov , Dave Hansen , Ingo Molnar , James Morse , Jarkko Sakkinen , Josh Poimboeuf , Kees Cook , Nam Cao , Oleg Nesterov , Perry Yuan , Thomas Gleixner , Thomas Huth , Uros Bizjak , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-sgx@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 3/6] x86/entry/vdso32: remove int80_landing_pad User-Agent: K-9 Mail for Android In-Reply-To: References: <20251026221208.1938173-1-hpa@zytor.com> <20251026221208.1938173-4-hpa@zytor.com> Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On October 28, 2025 11:54:43 PM PDT, Brian Gerst wrot= e: >On Sun, Oct 26, 2025 at 6:12=E2=80=AFPM H=2E Peter Anvin wrote: >> >> There is no fundamental reason for the int80_landing_pad symbol=2E If i= p >> falls within the vdso, and the vdso is moved, we should change the ip >> accordingly, regardless of mode or location within the vdso=2E This >> *currently* can only happen on 32 bits, but there isn't any reason not >> to do so generically=2E >> >> Note that if this is ever possible from a vdso-internal call, then the >> user space stack will also needed to be adjusted (as well as the >> shadow stack, if enabled=2E) Fortunately this is not currently the case= =2E >> >> At the moment, we don't even consider other threads when moving the >> vdso=2E The assumption is that it is only used by process freeze/thaw >> for migration, where this is not an issue=2E >> >> Signed-off-by: H=2E Peter Anvin (Intel) >> --- >> arch/x86/entry/vdso/vdso32/system_call=2ES | 1 - >> arch/x86/entry/vdso/vma=2Ec | 16 ++++++---------- >> arch/x86/tools/vdso2c=2Ec | 1 - >> 3 files changed, 6 insertions(+), 12 deletions(-) >> >> diff --git a/arch/x86/entry/vdso/vdso32/system_call=2ES b/arch/x86/entr= y/vdso/vdso32/system_call=2ES >> index 2a15634bbe75=2E=2Ed14eca4403c5 100644 >> --- a/arch/x86/entry/vdso/vdso32/system_call=2ES >> +++ b/arch/x86/entry/vdso/vdso32/system_call=2ES >> @@ -62,7 +62,6 @@ __kernel_vsyscall: >> >> /* Enter using int $0x80 */ >> int $0x80 >> -SYM_INNER_LABEL(int80_landing_pad, SYM_L_GLOBAL) > >This is still needed by do_fast_syscall_32()=2E > > >Brian Gerst > Yeah, that was a complete brainfart on my part=2E I'm already reworking th= e patchset, fixing this and adding more improvements=2E=20