March 2006 - Darwin-kernel - lists.apple.com

Re: A float point arithmetic in kernel extension
by Quinn 07 Mar '06

07 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com <http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgrammin…> <http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgrammin…> S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… At 21:56 -0800 6/3/06, Mike Smith wrote: Floating point math is not generally supported in the kernel; you'll need to find another way of doing what you need to do. Just to clarify this, we /do/ support the use of floating point (and vector) instructions in kernel code. For example, the Mac OS X audio sub-system makes extensive use of floating point in the kernel. However, there are caveats. This topic is covered pretty well in the documentation. The problem you're seeing is not related to floating point instructions, per se, but to floating point libraries. The availability, in kernel, of commonly used library functions is also covered in the documentation. Unfortunately, standard floating point library functions, like pow and acos, are not present in the kernel. In this respect, the difference between Xcode 1.5 and Xcode 2.2 is an improvement; there's no point allowing you to include <math.h> if the functions aren't available anyway. You will have to eliminate your dependency on these functions. I'm not a Maths Geek (tm), but there's got to be a way... This email sent to site_archiver(a)lists.apple.com

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Re: A float point arithmetic in kernel extension
by Mike Smith 07 Mar '06

07 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Mar 6, 2006, at 9:58 PM, wlq wrote: I have tried this for a long time, I think maybe asm can do. But where to find any information about asm programme in xcode? What exactly are you trying to do? = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… No, this won't help. Floating point operations in general are not supported in the kernel. You will need to find a different way to solve your problem. This email sent to site_archiver(a)lists.apple.com

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Re: A float point arithmetic in kernel extension
by wlq 07 Mar '06

07 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thank you. I have tried this for a long time, I think maybe asm can do. But where to find any information about asm programme in xcode? _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: A float point arithmetic in kernel extension
by Mike Smith 07 Mar '06

07 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Mar 6, 2006, at 9:53 PM, wlq wrote: = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I am building one kernel extension for my device and I need do some float point arithmetic. The problem is, In my code, I have added header file #include <math.h> And I have called some float point function pow(float, float), acos (float) etc. In xcode 1.5, the compiler shows ok when compile the project, but when I use kextload to load my KEXT into kernel, the console shows that kernel can't identify _pow, _acos. Floating point math is not generally supported in the kernel; you'll need to find another way of doing what you need to do. This email sent to site_archiver(a)lists.apple.com

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A float point arithmetic in kernel extension
by wlq 07 Mar '06

07 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com I am building one kernel extension for my device and I need do some float point arithmetic. The problem is, In my code, I have added header file #include <math.h> And I have called some float point function pow(float, float), acos(float) etc. In xcode 1.5, the compiler shows ok when compile the project, but when I use kextload to load my KEXT into kernel, the console shows that kernel can't identify _pow, _acos. In xcode 2.2, when compile the project, the compiler shows can't find header file math.h Any suggestions? Thanks & B.R. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Learning to read ktrace output?
by Terry Lambert 06 Mar '06

06 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com But you are probably looking for something like: <http://girtby.net/offerings/ktrace-parser/> instead. -- Terry On Mar 6, 2006, at 2:50 PM, James Reynolds wrote: -- Thanks, James Reynolds University of Utah Student Computing Labs james(a)scl.utah.edu 801-585-9811 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/tlambert%40apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… The FreeBSD manual page has been updated with more information; it's mostly applicable: <http://www.freebsd.org/cgi/man.cgi?query=kdump&sektion=1&apropos=0&manpath=… > It's an OK starting point, or you can just look at the source code for ktrace/kdump. Where does one turn to learn how to read the output of ktrace? Like, where do I learn what RET, CALL, GIO, NAMEI, getattrlist, ftruncate, pwrite, fd, etc means? (Google was particularly useless.) The BSD kernel book? I'm looking for kinda a quick intro so I can try to figure out why an app is beach balling with 3 repeated kernel calls. This email sent to tlambert(a)apple.com This email sent to site_archiver(a)lists.apple.com

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Learning to read ktrace output?
by James Reynolds 06 Mar '06

06 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com -- Thanks, James Reynolds University of Utah Student Computing Labs james(a)scl.utah.edu 801-585-9811 _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Where does one turn to learn how to read the output of ktrace? Like, where do I learn what RET, CALL, GIO, NAMEI, getattrlist, ftruncate, pwrite, fd, etc means? (Google was particularly useless.) The BSD kernel book? I'm looking for kinda a quick intro so I can try to figure out why an app is beach balling with 3 repeated kernel calls. This email sent to site_archiver(a)lists.apple.com

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Re: Kext resources
by Mike Smith 06 Mar '06

06 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Mar 6, 2006, at 10:20 AM, Eric Long wrote: Not really. That's the preferred way of doing it. = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I can see that kexts may contain a /Resources folder and put items into it, but what I don't see is how to read data from that folder in my kext. In user space, there's CFBundle/NSBundle and such. Do I have similar capabilities in the kernel? I have a chunk of data I want to store and load, but it's not obvious to me how to do it. Do I have to read it in user space and pass it in? This email sent to site_archiver(a)lists.apple.com

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Kext resources
by Eric Long 06 Mar '06

06 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com User-agent: Microsoft-Entourage/11.1.0.040913 Hi, I can see that kexts may contain a /Resources folder and put items into it, but what I don't see is how to read data from that folder in my kext. In user space, there's CFBundle/NSBundle and such. Do I have similar capabilities in the kernel? I have a chunk of data I want to store and load, but it's not obvious to me how to do it. Do I have to read it in user space and pass it in? Eric _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Mapping logical to physical memory addresses
by Mike Smith 05 Mar '06

05 Mar '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Mar 5, 2006, at 11:21 AM, Tony Scaminaci wrote: Not for a user-space application. How do you determine the amount of "free physical RAM"? You don't. You're mistaken. = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… Is there a system command or kernel call that returns the physical address corresponding to the logical address allocated by malloc? In my code, I first do a malloc for all of the free physical ram followed by mlock. mlock will not necessarily allow you to wire all available memory into your application, since the system requires a certain amount of free memory in order to operate. Because I'm only allocating from the free physical ram pool, all allocated memory resides in ram (which it must for a memory test application). This assumes a very naive model for your RAM test application, and one that cannot be supported by a modern operating system while running. However, the start address returned by malloc is a local address which I can't figure out how to map to the physical DIMM. If I run two instances of the program at the same time and allocate half the free ram to each instance, both instances have the same local start address. How does one figure out the physical address corresponding to these local addresses returned by malloc? Also, I'm under the impression that the memory manager doesn't run in single-user mode. Does that mean that these local addresses are really physical addresses in single-user mode? This email sent to site_archiver(a)lists.apple.com

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