DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 55RFEoOB1481603
Authentication-Results: delorie.com; dmarc=pass (p=none dis=none) header.from=cygwin.com
Authentication-Results: delorie.com; spf=pass smtp.mailfrom=cygwin.com
DKIM-Filter: OpenDKIM Filter v2.11.0 delorie.com 55RFEoOB1481603
Authentication-Results: delorie.com;
	dkim=pass (1024-bit key, unprotected) header.d=cygwin.com header.i=@cygwin.com header.a=rsa-sha256 header.s=default header.b=m2aTJ+Ka
X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 3226F3856260
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1751037289;
	bh=dSIQ15nvUY1p1XuBQzq4Rrr1eBEi2dMAf+V6aiUdooQ=;
	h=Date:To:Subject:References:In-Reply-To:List-Id:List-Unsubscribe:
	 List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc:
	 From;
	b=m2aTJ+KapsOJZsGQLTKUZptFkHb4Khz0/pBFixbSS3sgA2iJkU02vMikuOMBFTaWC
	 fAQx9hHy3Od496+iZWo5khN35CoIsgHTp7IdpOamr2HjK4Ga4bHFyiWEMViAkx9o31
	 jgAxTIstsS0RC1B+vyVeL9UVr7b79jfobaAprB0U=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org EAD36385B517
Date: Fri, 27 Jun 2025 17:10:15 +0200
To: Pip Cet <pipcet AT protonmail DOT com>
Subject: Re: XSAVE-related segfaults observed under wine
Message-ID: <aF60VympSWbCeu2n@calimero.vinschen.de>
Mail-Followup-To: Pip Cet <pipcet AT protonmail DOT com>, cygwin AT cygwin DOT com
References: <87bjq9457k DOT fsf AT protonmail DOT com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <87bjq9457k.fsf@protonmail.com>
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.30
Precedence: list
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe: <https://cygwin.com/mailman/options/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From: Corinna Vinschen via Cygwin <cygwin AT cygwin DOT com>
Reply-To: cygwin AT cygwin DOT com
Cc: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>, cygwin AT cygwin DOT com
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>

Hi Pip,

On Jun 27 14:41, Pip Cet via Cygwin wrote:
> My suggested fix is to align the value in %rbx to the next 64-byte
> multiple after the "cpuid" instruction is executed, by performing the
> assembler equivalent of $rbx += 63; $rbx &= -64; I tried this:
> 
> diff --git a/winsup/cygwin/scripts/gendef b/winsup/cygwin/scripts/gendef
> index 861a2405b..d681fde3f 100755
> --- a/winsup/cygwin/scripts/gendef
> +++ b/winsup/cygwin/scripts/gendef
> @@ -232,6 +232,8 @@ sigdelayed:
>  	movl	\$0x0d,%eax
>  	xorl	%ecx,%ecx
>  	cpuid	# get necessary space for xsave
> +	addq	\$63, %rbx
> +	andq	\$-64, %rbx # align to next 64-byte multiple

what about a oneliner instead by just aligning rsp?  As in

>  	movq	%rbx,%rcx
>  	addq	\$0x48,%rbx # 0x18 for alignment, 0x30 for additional space
>  	subq	%rbx,%rsp

  +     andq    \$-64, %rsp

Would you mind to create a git send-email compatible patch with a nice
commit message basically duplicating your great description of the
problem and matching "Fixes:" and "Signed-off-by:" lines?

You can send it here or to the cygwin-patches mailing list.


Thanks,
Corinna

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple