Date: Sun, 30 Jul 2006 22:03:54 +0200 From: Divacky Roman <xdivac02@stud.fit.vutbr.cz> To: hackers@freebsd.org Subject: Re: VM question related to faults Message-ID: <20060730200354.GA82547@stud.fit.vutbr.cz> In-Reply-To: <20060730105731.GA64955@stud.fit.vutbr.cz> References: <20060730105731.GA64955@stud.fit.vutbr.cz>
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On Sun, Jul 30, 2006 at 12:57:32PM +0200, Divacky Roman wrote: > hi, > > while working on SoC linuxolator project I am in a need of this: > > I need to do some operation on memory like mem1 = mem1 + mem2 etc. > where the mem1/mem2 access can trigger fault. (memory not mapped or something) to make it clear.. I am trying to access user-space memory from kernel. This needs to be atomic (its an implementation of linux futexes) I need to check from kernel if some memory is accessible and then perform an operation on this memory. All atomically. hence I need two things - function which checks wheter the memory is accessible and something which makes it atomic (some mutex/something which prevents other process to enter VM to unmap/etc. the memory in question) hope its a bit more clear now roman
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