January 2011 - kernelnewbies@kernelnewbies.org

viewing complete command
by Rahul Kumar Jan. 10, 2011

Jan. 10, 2011

Hi, I just want to know the command option for ps...so that i can see the complete arguments for the executable running. Right now, i'm seeing the truncated output. This i need because i would like to rerun the process with the same arguments. Can any one help me out on this.

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Linux - Getting your Hands Wet & Dirty
by Sakshi Malhotra Jan. 10, 2011

Jan. 10, 2011

Hi,Maybe I am not the first one to ask such a question...but couldnt stop myself either...I have read all the relevant books on linux...such as LKD & LDD. I have tried getting some projects on soureforge.net as well ...however, i have not been lucky so far.I want to land up with a job in Linux Kernel but everywhere I get rejected for lack of practical experience.Dont know what to do to get relevant practical experince which gets counted and helps me land up with a job.I am low on morale and confidence...pls suggest.Regards,Sakshi

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How to set Stacked VLAN between two machines in LINUX
by Ramana Reddy Jan. 10, 2011

Jan. 10, 2011

Hi Everyone, Does current linux kernel supports S-VLAN support. If yes, how to configure that. Thanks, Ramana.

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please unsubscribe
by gnulinux54 Jan. 10, 2011

Jan. 10, 2011

please unsubscribe don't remember password

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how to compile the 0.01 version of kernel
by KK Jan. 10, 2011

Jan. 10, 2011

Hello All, I was going through the linux kernel newbie articles in kernelnewbies.com and found it very interesting. I downloaded the tarballs for the 0.01 version of kernel from : http://www.kernel.org/pub/linux/kernel/Historic/ Then the next thing I was trying to do was to compile the source code and try to understand the various methods/function calls, system calls etc, but I'm not able to compile the code, I'm getting the following errors: $ make -f Makefile gas -c -o boot/head.o boot/head.s make: gas: Command not found make: *** [boot/head.o] Error 127 Then I searched in the web for GAS and found that it GNU AS. I've "as" installed in my box, so I tried creating a symlink with the name "gas" but then bumped into another error: $ make gas -c -o boot/head.o boot/head.s gas: unrecognized option `-c' make: *** [boot/head.o] Error 1 Is GNU AS same as "as" ? when running version check I got this: $ as --version GNU assembler (GNU Binutils) 2.20.51.20100410 Copyright 2010 Free Software Foundation, Inc. This program is free software; you may redistribute it under the terms of the GNU General Public License version 3 or later. This program has absolutely no warranty. This assembler was configured for a target of `i686-cygwin'. I tried searching on the web to find ways to install "GNU AS" but could not get any useful info. I'm facing similar problem with "GNU LD". Is it different from the "ld": $ ld --version GNU ld (GNU Binutils) 2.20.51.20100410 Copyright 2010 Free Software Foundation, Inc. This program is free software; you may redistribute it under the terms of the GNU General Public License version 3 or (at your option) a later version. This program has absolutely no warranty. Can someone help me installing these two or let me know what is the fix for the same. I'm running cygwin on Win7-64 bit Thanks

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Help with head_64.S
by lichangshou Jan. 9, 2011

Jan. 9, 2011

The same problem I asked before. I want to modify kernel image's page table from 2M to 4K. In arch/x86/kernel/head_64.S, I add another level page table, make pmd point to the new page table. However, after compile and boot it, the kernel cannot work and always reboot. I try many kind of port, it still cannot work normally. Here is the context of my modified code : ----------------------------------------------------- /* Automate the creation of 1 to 1 mapping pmd entries */ #define PMDS(START, PERM, COUNT) \ i = 0 ; \ .rept (COUNT) ; \ .quad (START) + (i << PMD_SHIFT) + (PERM) ; \ i = i + 1 ; \ .endr #define PTDS(START, PERM, COUNT) \ i = 0 ; \ .rept (COUNT) ; \ .quad (START) + (i << PAGE_SHIFT) + (PERM) ; \ i = i + 1 ; \ .endr .data /* * This default setting generates an ident mapping at address 0x100000 * and a mapping for the kernel that precisely maps virtual address * 0xffffffff80000000 to physical address 0x000000. (always using * 2Mbyte large pages provided by PAE mode) */ NEXT_PAGE(init_level4_pgt) .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE .org init_level4_pgt + L4_PAGE_OFFSET*8, 0 .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE .org init_level4_pgt + L4_START_KERNEL*8, 0 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE NEXT_PAGE(level3_ident_pgt) .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE .fill 511,8,0 NEXT_PAGE(level3_kernel_pgt) .fill L3_START_KERNEL,8,0 /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ .quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE .quad level2_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE NEXT_PAGE(level2_fixmap_pgt) .fill 506,8,0 .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */ .fill 5,8,0 NEXT_PAGE(level1_fixmap_pgt) .fill 512,8,0 NEXT_PAGE(level2_ident_pgt) /* Since I easily can, map the first 1G. * Don't set NX because code runs from these pages. */ PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD) NEXT_PAGE(level2_kernel_pgt) /* * 512 MB kernel mapping. We spend a full page on this pagetable * anyway. * * The kernel code+data+bss must not be bigger than that. * * (NOTE: at +512MB starts the module area, see MODULES_VADDR. * If you want to increase this then increase MODULES_VADDR * too.) */ /* PMDS(0, __PAGE_KERNEL_LARGE_EXEC, KERNEL_IMAGE_SIZE/PMD_SIZE)*/ #define NEW_PMD_PORT (0x0 | _PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED) PMDS(level1_kernel_pgt - __START_KERNEL_map, NEW_PMD_PORT, PTRS_PER_PMD) NEXT_PAGE(level1_kernel_pgt) #define NEW_PTD_PORT (0x0 | _PAGE_PRESENT | _PAGE_RW | |_PAGE_USER | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL) PTDS(0, NEW_PTD_PORT, KERNEL_IMAGE_SIZE/PAGE_SIZE) NEXT_PAGE(level2_spare_pgt) .fill 512, 8, 0 ----------------------------------------------------------------------------------------------

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help with status of realtek wifi driver?
by Dave Stevens Jan. 9, 2011

Jan. 9, 2011

Hi, My Samsung N220 has a RTL8192E wifi chip. The windows 7 driver works fine, but I think the Linux driver is in staging. Does anyone know how to find out if there is work being done on this driver or who is doing it? Flaky in Ubuntu. lspci -nn shows: 05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8192E Wireless LAN Controller [10ec:8192] (rev 01)

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spin_lock and scheduler confusion
by Viral Mehta Jan. 8, 2011

Jan. 8, 2011

Hi , I need your help to solve below confusion. 1. I know that spin_lock_irqsave, disables premption and local_irq. 2. There is some below piece of kernel code running on Quad core Machine. spin_lock_irqsave(&lock, flags); some_large_critical_section //sleep of 5 minutes //I know there should be as small as possible task in critical section // treat this as an example only spin_lock_irqrestore(); 3. One of the CPU core tries to execute this code and so acquires the lock. 4. Now, second core is also goes to execute same piece of code and so will keep spinning for lock Now, the question is Will EVER second CPU core get chance to execute another task ? Ever if timeslice is over for the current task ? What if scheduler code is running on CPU core-3 and sees that timeslice for task running on CPU core-2 has expired ? I guess timeslice expire case is not as same as preemption. Or may be I am terribly wrong. Please help, Thanks, Viral ________________________________ The contents of this e-mail and any attachment(s) may contain confidential or privileged information for the intended recipient(s). Unintended recipients are prohibited from taking action on the basis of information in this e-mail and using or disseminating the information, and must notify the sender and delete it from their system. L&T Infotech will not accept responsibility or liability for the accuracy or completeness of, or the presence of any virus or disabling code in this e-mail" ______________________________________________________________________

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Questions about complete
by loody Jan. 8, 2011

Jan. 8, 2011

Dear all: I know complete will wake up the process who call wait_complete. Is there any methods I can use to measure how long from calling complete to the process that detect done=1? Regards, miloody

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LDD3 examples updated
by Javier Martinez Canillas Jan. 8, 2011

Jan. 8, 2011

Hello, I see many people in the list asking where do I start? In my opinion the best way to learn kernel development is first learning some basic concepts and start coding to get your hands dirty. The Linux Device Drivers 3 book is a good start. Both the book and source code examples are freely available. The problem is that the book is a few years old and the example drivers do not compile in recent kernels. I started a project to keep the LDD3 examples up-to-date with recent kernels. The git tree can be cloned from git://github.com/martinezjavier/ldd3.git I will try to keep the code always in sync with linux-next but there will be tags to stable versions. Now there are tags that compile with kernel versions 2.6.32, 2.6.35 and 2.6.37. I didn't try all the drivers with the three kernel versions, just compile tested. So any bug, comment or patch is always welcome -- Best regards, ----------------------------------------- Javier Martínez Canillas (+34) 682 39 81 69

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