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J . Bottomley" , Helge Deller , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , "David S . Miller" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Chris Zankel , Max Filippov , Arnd Bergmann , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org Subject: Re: [PATCH v3 00/24] Remove COMMAND_LINE_SIZE from uapi Message-ID: References: <20230214074925.228106-1-alexghiti@rivosinc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-GUID: UOzvHh6KowmpY_9himJ0Lcj8lppogDkY X-Proofpoint-ORIG-GUID: 43TrAfyms_R0LeogELAFDthALGccI9YC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.170.22 definitions=2023-02-14_06,2023-02-13_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 spamscore=0 adultscore=0 priorityscore=1501 phishscore=0 suspectscore=0 lowpriorityscore=0 mlxscore=0 bulkscore=0 malwarescore=0 mlxlogscore=999 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2302140077 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230214_011944_646075_F333A64B X-CRM114-Status: GOOD ( 33.82 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Feb 14, 2023 at 09:58:17AM +0100, Geert Uytterhoeven wrote: > Hi Heiko, > > On Tue, Feb 14, 2023 at 9:39 AM Heiko Carstens wrote: > > On Tue, Feb 14, 2023 at 08:49:01AM +0100, Alexandre Ghiti wrote: > > > This all came up in the context of increasing COMMAND_LINE_SIZE in the > > > RISC-V port. In theory that's a UABI break, as COMMAND_LINE_SIZE is the > > > maximum length of /proc/cmdline and userspace could staticly rely on > > > that to be correct. > > > > > > Usually I wouldn't mess around with changing this sort of thing, but > > > PowerPC increased it with a5980d064fe2 ("powerpc: Bump COMMAND_LINE_SIZE > > > to 2048"). There are also a handful of examples of COMMAND_LINE_SIZE > > > increasing, but they're from before the UAPI split so I'm not quite sure > > > what that means: e5a6a1c90948 ("powerpc: derive COMMAND_LINE_SIZE from > > > asm-generic"), 684d2fd48e71 ("[S390] kernel: Append scpdata to kernel > > > boot command line"), 22242681cff5 ("MIPS: Extend COMMAND_LINE_SIZE"), > > > and 2b74b85693c7 ("sh: Derive COMMAND_LINE_SIZE from > > > asm-generic/setup.h."). > > > > > > It seems to me like COMMAND_LINE_SIZE really just shouldn't have been > > > part of the uapi to begin with, and userspace should be able to handle > > > /proc/cmdline of whatever length it turns out to be. I don't see any > > > references to COMMAND_LINE_SIZE anywhere but Linux via a quick Google > > > search, but that's not really enough to consider it unused on my end. > > > > > > The feedback on the v1 seemed to indicate that COMMAND_LINE_SIZE really > > > shouldn't be part of uapi, so this now touches all the ports. I've > > > tried to split this all out and leave it bisectable, but I haven't > > > tested it all that aggressively. > > > > Just to confirm this assumption a bit more: that's actually the same > > conclusion that we ended up with when commit 3da0243f906a ("s390: make > > command line configurable") went upstream. > > Commit 622021cd6c560ce7 ("s390: make command line configurable"), > I assume? Yes, sorry for that. I got distracted while writing and used the wrong branch to look this up. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv