From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 2DF3D3E0227 for ; Thu, 25 Jun 2026 12:08:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782389305; cv=none; b=CDxXRbZrWioFCT36yNSgSexNR7ViMvlEdYRJHCScJTpWc903wPrE6KcnYIPVm9jS3aiGcut7CQKDe/GkYx787y6qge3i4o6oSGjSQR153JX5w8M9VtyTwjHR5XepoVb3EGOQM3/P/3EzoI/j9RmRc/3HCl5ZUUNvjJMOvnPZi5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782389305; c=relaxed/simple; bh=rnC19SJIB8IwjPpZjyOW9vAFG81ZtsEUSHRdP82RYv4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NeZDJcopslq+AOdMXwqx9UCic92hoZQiC3kPELDpCAMyTeEPaqTZt5fR8RMMajq64O6kMESTIBjoncmFi17yWLAJvQ6dviZdYPzNv/UiM8/v2oWGDeJGQNhu9p7xwbvTGtL72b8mSA/maO3MW9lvLlYlsbBLrIwnV4S6Vkp+YUE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=hZWj1sxv; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=NNthX3RL; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="hZWj1sxv"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="NNthX3RL" Date: Thu, 25 Jun 2026 14:08:19 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1782389301; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rnC19SJIB8IwjPpZjyOW9vAFG81ZtsEUSHRdP82RYv4=; b=hZWj1sxvXAx2kbIij7hPOANuGEApe9ROSVloikyhvbWue0ENgZXJP0wx9pYQCc7L3CWPL2 azZsEGY8Kq4xT+YfwPi6Uj7b18Z0+b9F4uy/tjceDqTgKW2Sbj1EtzxEhPDU6N9M+Qan7R 95Xq89RMt1ksBDn8S0FrBlGRHj1tsbl0G0q0kXlBofs0wzzwZHwx5nT4kK8ee1oj55LMb4 bZYvX3RfnrjhMJsttIQ8i+4ZGo4GdUGB49YAb6dEEAKTUpU8bmKGKqzVe41cGgKXzmw1ec YxKTCLcV9k9wHDF++loCqt5YMfACC48XySlqNiYUtAPuAI2tffl2sz5y2TlJCQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1782389301; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rnC19SJIB8IwjPpZjyOW9vAFG81ZtsEUSHRdP82RYv4=; b=NNthX3RLO/2AwrFk7DPc9eyAGWhbPpJ8XQgDtdhk4wHM9jdyiePonsiFcXkG/66zDdTtDk sPSHQv6K0tRz8RBg== From: Sebastian Andrzej Siewior To: Russell King Cc: Xie Yuanbin , clrkwllms@kernel.org, rostedt@goodmis.org, linusw@kernel.org, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, liaohua4@huawei.com, lilinjie8@huawei.com Subject: Re: [PATCH] ARM: enable interrupts when arm_notify_die() is handling user mode errors Message-ID: <20260625120819.K5e1OVeG@linutronix.de> References: <20260625073522.182503-1-xieyuanbin1@huawei.com> <20260625085034.tvyGSmaP@linutronix.de> <20260625093008.e5I4bh-_@linutronix.de> Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: On 2026-06-25 11:20:13 [+0100], Russell King wrote: > > is not worth doing it? With this I can my little testcase working. >=20 > No, it isn't, because if you enable PERF_EVENTS then BKPT breaks. > hw_breakpoint.c claims this vector. I see. =E2=80=A6 > BKPT is a total mess. Understood. > > it does cond_local_irq_enable() which enables the interrupts if they > > were enabled by the "caller", sends the signal (SIGTRAP). >=20 > I'm happy with that approach as far as interrupts go, but we can't > change the behaviour for FSR=3D2 again, beyond fixing LinusW's > commit (which has recently been reported as a regression.) >=20 > Note that the change which makes this raise a SIGTRAP rather than > SIGBUS when PERF_EVENTS=3Dy could _also_ be reported as a regression > that we would have to fix, and making FSR=3D2 raise a SIGTRAP now > could very well invite that regression to be reported. >=20 > Essentially, I don't think we can "fix" BKPT to always raise SIGTRAP. > The BKPT instruction is something the kernel has never _officially_ > supported. It looked like an easy fix. You explained that it is a bigger mess with "other features" and so on. Given that and the fact that it was never supported, I would appreciate just to enable interrupts before the (SIGBUS) signal is sent. Sebastian