From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:49330 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726386AbfKNKLy (ORCPT ); Thu, 14 Nov 2019 05:11:54 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id xAEABI87147202 for ; Thu, 14 Nov 2019 05:11:53 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2w92x53pxd-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 14 Nov 2019 05:11:53 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 14 Nov 2019 10:11:50 -0000 Subject: Re: [PATCH v1 1/4] s390x: saving regs for interrupts References: <1573647799-30584-1-git-send-email-pmorel@linux.ibm.com> <1573647799-30584-2-git-send-email-pmorel@linux.ibm.com> <7f40bf69-6e34-7613-1ab5-83e09464c0b0@linux.ibm.com> From: Pierre Morel Date: Thu, 14 Nov 2019 11:11:45 +0100 MIME-Version: 1.0 In-Reply-To: <7f40bf69-6e34-7613-1ab5-83e09464c0b0@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Message-Id: Sender: linux-s390-owner@vger.kernel.org List-ID: To: Janosch Frank , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, david@redhat.com, thuth@redhat.com On 2019-11-13 17:12, Janosch Frank wrote: > On 11/13/19 1:23 PM, Pierre Morel wrote: >> If we use multiple source of interrupts, for exemple, using SCLP console >> to print information while using I/O interrupts or during exceptions, we >> need to have a re-entrant register saving interruption handling. >> >> Instead of saving at a static place, let's save the base registers on >> the stack. >> >> Note that we keep the static register saving that we need for the RESET >> tests. >> >> We also care to give the handlers a pointer to the save registers in >> case the handler needs it (fixup_pgm_int needs the old psw address). > So you're still ignoring the FPRs... > I disassembled a test and looked at all stds and it looks like printf > and related functions use them. Wouldn't we overwrite test FPRs if > printing in a handler? If printf uses the FPRs in my opinion we should modify the compilation options for the library. What is the reason for printf and related functions to use floating point? I will have a deeper look at this. Regards, Pierre -- Pierre Morel IBM Lab Boeblingen