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Peter Anvin" Cc: Thomas Gleixner , LKML , Peter Zijlstra , Michael Ellerman , Shrikanth Hegde , linuxppc-dev@lists.ozlabs.org, Kees Cook , Huacai Chen , loongarch@lists.linux.dev, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Sven Schnelle , linux-s390@vger.kernel.org, x86@kernel.org, Mark Rutland , Jinjie Ruan , Andy Lutomirski , Oleg Nesterov , Richard Henderson , Russell King , Catalin Marinas , Guo Ren , Geert Uytterhoeven , Thomas Bogendoerfer , Helge Deller , Yoshinori Sato , Richard Weinberger , Chris Zankel , linux-arm-kernel@lists.infradead.org, linux-alpha@vger.kernel.org, linux-csky@vger.kernel.org, linux-m68k@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-um@lists.infradead.org, Arnd Bergmann , Vineet Gupta , Will Deacon , Brian Cain , Michal Simek , Dinh Nguyen , "David S. Miller" , Andreas Larsson , linux-snps-arc@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, Michal =?iso-8859-1?Q?Such=E1nek?= , Jonathan Corbet , linux-doc@vger.kernel.org Subject: Re: [patch 00/18] entry: Consolidate and rework syscall entry handling Message-ID: <20260831085056.34274A00-hca@linux.ibm.com> References: <20260707181957.433213175@kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=bc1bluPB c=1 sm=1 tr=0 ts=6a954078 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=kj9zAlcOel0A:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=2rmWDWJpZfqxup52QhcA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwODMxMDA3MiBTYWx0ZWRfXw6StCSqGUaXh WvbpCQlGtz7BWihs+RH7DTv2WTOPxVyCWDhiSWtYE+xXgludqixVfK/gU8MUaWS0fxPWdxy86vH qJzG6nhsABnZyATt5K5eJawaXFm8xNE= X-Proofpoint-ORIG-GUID: bDXbK4NJXMMf6_5R5lg1wFJEO5GSpFz5 X-Proofpoint-GUID: Fhr_wfi5ePHh4Bqv3MhKtt0iPRZ1Mvkg X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODMxMDA3MiBTYWx0ZWRfX/htDxJBtEHnv Z5NhKYazvuvBRJ72zC10F4fqCuZQvNxl5T1bxWCM9YyDyUuOyarWnRe1p0lqpKZl/OmyRFcmZLf ktLOOUR/RrJ6H/n8LU3DyRN14Rj88+RKLatjVJj6EvUm7yCYuy01GuzOqCiTMwCDp3qPyD8ygcz 8e7DrOBxrdld6/gHT5EMTdlMQoVKjlCd8tRGftrZtFR0eBrKEt+PFXrl5pqVW+wMvV30DgdS65s FO2OVicoQhWTWZLtRydH/w0eDM4R+aziyu8zv53VSgwZjxKL71DDEhdZB1VFr5JeZaTp0hNvCNd fL1C2mdKKTto6StljkY/Esj1kJ2CLVmDhxayGEQpB6INuQ8vyDvgd1hcoKr++IMzU8bbI32PX2p erwW4FtLz+3ZSzAofzRUQ2Kh1tXMYtSiayqZ9s635kOCihBZsW9PohTK3Pmd5E5U5z+A/YfXl7T OPEW+V8lEUn+zLxSJdQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-31_03,2026-08-27_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 suspectscore=0 adultscore=0 malwarescore=0 spamscore=0 lowpriorityscore=0 phishscore=0 clxscore=1011 priorityscore=1501 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608310072 On Thu, Aug 27, 2026 at 03:22:35PM -0700, H. Peter Anvin wrote: > This isn't a hard thing to solve in any way: replacing the pointer argument > with a two-element structure return would do the trick. As far as I know, > *all* architectures that support Linux support returning structures with two > register-sized values in registers. That is unfortunately not true. The s390 ABI defines that structures, regardless of size, are returned in a return value buffer allocated by the caller.