August 2012 - kernelnewbies@kernelnewbies.org

Re: Linux kernel boot process
by Kumar Sukhani Aug. 5, 2012

Aug. 5, 2012

> Hi Kumar, > > I will be glad to provide my support as much as possible. I don't have > much idea on how kernel power management subsystem works. So I may not > be up to your speed but I can help you for sure. What kind of research > you are planning to work on? I will send you personal mail regarding what all I am planning till end of the day. If any1 else is also interested can join with us for the work. -- Be Happy Always +919579650250

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Linux kernel boot process
by Kumar Sukhani Aug. 4, 2012

Aug. 4, 2012

I heard that windows 8 have change its boot process to a hybrid mood. In which it shutdowns the user applications and hibernates the kernel and device drivers[1]. Can the same be introduce in Linux kernel? [1] http://www.zdnet.com/windows-8-hybrid-mode-brings-faster-boot-3040093896/ -- Be Happy Always +919579650250

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how to subrie it
by 梨落 Aug. 3, 2012

Aug. 3, 2012

asd as d

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arm L_PTE_XXX entry addition for Debugging purpose
by Dhyan Aug. 2, 2012

Aug. 2, 2012

Dear All, >From linux(2.6.35) arm page table architecture i can see we have one hardware page table and there is corresponding Linux page table Entry (L_PTE_*).The "Linux" PTE definitions are as like below from arch/arm/include/asm/pgtable.h. #define L_PTE_PRESENT (1 << 0) #define L_PTE_FILE (1 << 1) #define L_PTE_YOUNG (1 << 1) #define L_PTE_BUFFERABLE(1 << 2) #define L_PTE_CACHEABLE (1 << 3) #define L_PTE_USER (1 << 4) #define L_PTE_WRITE (1 << 5) #define L_PTE_EXEC (1 << 6) #define L_PTE_DIRTY (1 << 7) #define L_PTE_COHERENT (1 << 9) #define L_PTE_SHARED (1 << 10) So is it possible to add one more #define L_PTE_DEBUG (1 << 11) for my debugging purpose (basically to trap all the write to that page and set this bit when write happens and clear it off in another thread )? Or is there any limitation like we can use only L_PTE till 10th bit ? So could you please help -- Thanks & Regards Dhayn

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What is purpose of /init
by Rahul Bedarkar Aug. 2, 2012

Aug. 2, 2012

Hi, I just saw contents of /init on my system. #!/bin/sh # devtmpfs does not get automounted for initramfs /bin/mount -t devtmpfs devtmpfs /dev exec 0</dev/console exec 1>/dev/console exec 2>/dev/console exec /sbin/init $* Can someone explain what is meant for ? Regards, Rahul B.

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How to test PCIe bus speed and correctness
by hz hanks Aug. 1, 2012

Aug. 1, 2012

Hi, all: I'm working on an embedded system using PCIe bus. Now my task is to test the speed and correctness of the PCIe bus. In order to do that: 1. find the corresponding resource I want to read and write ---- /sys/bus/pci/devices/XXXX:XX:XX.X/resource0 2. in my program, use function open() to open the resource 3. remap it use mmap() like this: long *where = (long*) mmap( NULL, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0) 4. then I can read and write through PCIe bus like this: where[0]; //read where[0] = 1; //write Is this the correct and entire process to test it in Linux? Besides, I also worry about the cache's effect. I will actually read/write the register of PCIe switch through PCIe bus. Presumably, they're actually IO from the perspective of Linux, and Linux should not cache it. Is it correct? Thanks a lot. Best, Hanks

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Re: arm L_PTE_XXX entry addition for Debugging purpose
by Vladimir Murzin Aug. 1, 2012

Aug. 1, 2012

Hi! AFAIK it's PG_dirty page flag. Hope this helps! Vladimir Murzin ------Original Message------ From: Mulyadi Santosa Sender: kernelnewbies-bounces(a)kernelnewbies.org To: Dhyan Cc: bill4carson Cc: kernelnewbies(a)kernelnewbies.org Subject: Re: arm L_PTE_XXX entry addition for Debugging purpose Sent: 1 Aug 2012 09:57 Hi... Sorry for crossing in... On Wed, Aug 1, 2012 at 11:53 AM, Dhyan <linuxdhyan(a)gmail.com> wrote: > Sorry to ask,but is there any other good way to find the written pages of a > user process? by "written", you mean "dirty" pages? if yes, IIRC there's a flag that marks so....but that is for x86 and I forgot the name... -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com _______________________________________________ Kernelnewbies mailing list Kernelnewbies(a)kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies --

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system stucks in run_init_process
by Rahul Bedarkar Aug. 1, 2012

Aug. 1, 2012

Hi, I have disabled CONFIG_DEVTMPFS in kernel config and system stucks in run_init_process call which is called after freeing initmem. Any idea why this is happening. If devtmpfs is enabled, it runs normally. I am using 3.3.2 kernel. Thanks, Rahul B.

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