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b=LrjaOiT0/kgKG5xJcHuIQQl96aDNH27jEWYo6/eukxIaqQwYL0Yi2fb+zu/vFRBId DV/PZj2ePkgKFhE9/F4nvTYUADBF7H7T9RJOwDn3NIgMGlyMKcDuTAtoTIIkUsgDb6 x1URYwePs3Vebu4nOuyyzGzHW5Vn2MCe8aXxTi+YGMS6b0csgZWtq74p7c08jB9xPQ ZpKgg9fwiync7utyBiMm2bPjVpvUOrU7S6mG7pstrUJvNj/jPcuRO+yDhhTGtADvXL 1IZ7ntsJFFvW9x/WXyQUNm7oAqTFgJ+zZzw2Hn0ou+zpclpaPwQJ68poxNuVNU2M6q o+8PkQiPxtQUA== Date: Fri, 2 Oct 2026 12:53:31 +0100 From: "Lorenzo Stoakes (ARM)" To: Geert Uytterhoeven Cc: "David Hildenbrand (Arm)" , Hajime Tazaki , johannes@sipsolutions.net, linux-mm@kvack.org, liam@infradead.org, rbm@suse.com, akpm@linux-foundation.org, luto@amacapital.net, brendan.jackman@linux.dev, liuhangbin@gmail.com, corbet@lwn.net, kees@kernel.org, broonie@kernel.org, mhocko@suse.com, rppt@kernel.org, shuah@kernel.org, surenb@google.com, vbabka@kernel.org, wad@chromium.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-um@lists.infradead.org, daniel@thingy.jp Subject: Re: [PATCH v4 1/2] selftests: run tests on nommu architecture Message-ID: References: <20260929235711.2287931-1-thehajime@gmail.com> <20260929235711.2287931-2-thehajime@gmail.com> <94759bed23f00d2044005e36be6f72f297e092f0.camel@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 264EAC0006 X-Stat-Signature: 6ahqonkgkw1sewgdu893y99o119roq9w X-HE-Tag: 1790942020-55667 X-HE-Meta: U2FsdGVkX1+qUMiTs/oSCN7nDuckErCg13xLK2bV6oP6SIetDfiMmVVGq5dOypHFlfr3mVPmuQK0+FqYXn+BVNmHcsx4yrOJzByEMRJsfct3vNFt1mXSyco6hHV9J/y83IOQCg/gOZQ4MElxVoG3UY+Xdqt9LdQc6YYoCeKoF/sJI2TBKyXLdaPyxAoL5aV8z/g+bfcfjBFgQEmoSXTiIWnr1/CQbuL295NH3kLTLUOG1X7r0wQPhH9jT1iW8qiWQo9IXwN25BtsI0CUdTe2JB5XP0Tuo3fCyn4Jfm9vJzfVQggVKZWAxOncfXMJgyKQFWWoOu6dU3x3YqbzzLjPjWcBXfUT6kJK5lK0jydvonX4dnzLd5C2crZWR3BNAP8I9h0LQzTt42xxMeooGGECzDDBwquXkVaSGlcfz7kb2f0YV5CLIwhWou/Xrvq/IZiSJnW+VKE7VUqYeg6x0T/ZaB1gqRS4vass8Vf2aRlW5mE4sioGGT7/92e8bG5R5EpNLOj9/OpAqDRR3GY+LdjIinZ7wF56KK2BofPLgxb6l+WF1NFYVnAlPd4zAeo7/5/eqSMkJuVeiFUkdHBVinZ+AtJTIg+4S0og4+mSwcBMjWUKvy3IbUKEaW9Dhl1CF6OYenV4bjVcTdU3urO80YjV1/bmfOx+hVvRD1zeJzcWvS3wpiuQiczH/oQklm82VtD+5FB8jx5kKKtR4HnNqi78aOV+sResqRGKZ0XuN/DUkgo+0SPFnkMEWaEwssVE8lLgBSgpy+Eg4RbxEGGzW9s6zqxwYkBqZKg4cOY+pqj+SMPiHNW+MQapZwoA9FriVYUmuojd0enikBpVJ9G/A9B6BRk0WYdjbbpoLJHBfPvL4QC32+RmLkYaoKO4sfwSK09pJrocoxdsmACnjcYOKzdF2Qqi5qxy3xtSLbN09JKXayX0DuWJM3PnaqvDjKQy03aAPTdLVXG6AGfyyNNOXzr gdSyu22a hEacOmevecr2QyDEXkZ0z3dN7U80okcYDQgztTrC/1ztMPoxqZEE0H1cZ10mBfZ0o+pVSOJKkd+7vIQK2nGoU5jbz0tUSZJB10IuHF1cbQ0iGB5LCDmsBFYLFbIx+A07cOn5R1mJmgbhuWb7u+cjcWqlCACmo7Su9ht2BM/AbhFQr8WMjkwJTQrCB+jP9d//l65t05owk43/66gbNPeQ4+UDfgsboX6K2rKu9FoCJWIxc4bl9y5Xag7VaHFPL9dAm971kSSw/uGgIdotVwzfaBvN40w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Oct 02, 2026 at 01:38:31PM +0200, Geert Uytterhoeven wrote: > On Fri, 2 Oct 2026 at 10:10, Lorenzo Stoakes (ARM) wrote: > > But fork() -> -EINVAL or -ENOSYS = nommu, then just have the child quit and > > etc. should do it. > > fork() is not strictly an MMU-feature (you can implement fork on nommu > if all memory accesses are done relative to a base address register), > while I think mprotect() is an MMU-feature. Unless it can also be used > to change the protection using the one or two BARs most MCU haves? > Anything else that is a real MMU-feature? Non-identity mmap()? Does any nommu arch implement fork() in linux? -- Cheers, Lorenzo