I mean RAM based.
On Fri, Mar 6, 2009 at 3:50 PM, sahlot arvind wrote:
> Try writing memory based file system.
>
>
> On Fri, Mar 6, 2009 at 3:35 PM, Shyam Burkule wrote:
>
>> Hi Greg, Thanks for your reply.
>>
>>
>> Actually I am new to file system, I
Try writing memory based file system.
On Fri, Mar 6, 2009 at 3:35 PM, Shyam Burkule wrote:
> Hi Greg, Thanks for your reply.
>
>
> Actually I am new to file system, I did work in memory management of Linux
> kernel. My concern is to understand file system, block architecture etc. I
> started read
> mic...@michaelblizek.twilightparadox.com> wrote:
> >
> > > Hi!
> > >
> > > On 23:47 Wed 04 Mar , sahlot arvind wrote:
> > > > Hi All,
>
> ...
>
> > > > 2. If kernel is not preemptible then do we really need a separate
>
Hi All,
Just had couple of questions:
1. kernel is preemptible if we are running in kernel mode and not holding
any lock. What if we preempt the kernel even when we are holding lock?
Assuming process A and B are trying to execute the same kernel path. So what
if something like this happens:
A get
Just to add more, CPL is used to protect the kernel memory from user land
programs. e.g. kernel space memory is marked as accessible when CPL=0 thus
while running in user mode (CPL=3) you cannot access kernel memory (address
space).
There are other CPL i.e. 1, 2, which are less privileged then 0 b
Thanks Rahul.
Luckily I got gcc-3.4.2 built using gcc-4.3.2 and also got bochs-2.2.6 built
using gcc-3.4.2 and its working fine now..
On Mon, Dec 29, 2008 at 8:18 AM, Rahul Pydimukkala wrote:
> On 00:38 Mon 29 Dec , sahlot arvind wrote:
> > Thanks guys.
> > I see that b
based distros.
>
> Let me know if that helps.
>
> -
> Rahul
>
>
> On 05:22 Sat 27 Dec , sahlot arvind wrote:
> > This is the error:
> >
> > cd iodev && \
> > make libiodev.a
> > make[1]: Entering directory `/home/arvind/os
:bx_devices_c()':
devices.cc:48: warning: deprecated conversion from string constant to
'char*'
make[1]: *** [devices.o] Error 1
make[1]: Leaving directory `/home/arvind/osEngg/tools/bochs-2.1.1/iodev'
make: *** [iodev/libiodev.a] Error 2
I dont know why it is coming. I am using gcc-3
azz...@free-electrons.com> wrote:
> Le Sat, 27 Dec 2008 02:23:47 -0500,
> "sahlot arvind" a écrit :
>
> > I was trying to do all that on FC9 but unfortunately my system
> > crashed and I have installed Ubuntu now.
> > I am new in dealing with things like se
homas.petazz...@free-electrons.com> wrote:
> Le Fri, 26 Dec 2008 05:45:17 -0500,
> "sahlot arvind" a écrit :
>
> > I am trying to use bochs for learning linux kernel. But I am unable
> > to build bochs from its source code.
>
> You should probably try to
Hi Everyone,
I am trying to use bochs for learning linux kernel. But I am unable to build
bochs from its source code.
I am getting a compile time error. I am trying to build bochs-2.1.1 with
gcc-4.3.2.
I have tried with gcc-3.4.2 and gcc-3.4.0 as well. The error which comes
while using gcc-4.3.2 g
Well I think during context switch [schedule()] we disable interrupts and
thus there is no point of corruption.
Anyway specific to your query,
actually i saw that ..
set_current_state (TASK_INTERRUPTIBLE)
schedule()
I guess there must be some sort of locking etc. if you can locate me in the
code
In case of exec, a separate grep is invoked for each file found by find. So
if there are 100 files found, you will be invoking 100 greps.
In case of xargs, a set of files is given as argument to grep, you can also
specify the number of files to be given in each set.
e.g. find . -type f -iname "*.h
Since all processes are forked out of some already existing process, I guess
you can place a hook in the implementation of fork. Maybe inside
kernel/sched.c. Similarly look for the function which cleans up the process
information when it gets over, that should be the place to put in the other
hook.
I am not sure but I think once oops happens then you may or may not remove
the module. I think it really depends on how much the oops has affected the
system. Try force remove though but I vaguely recall the same problem and I
had to resort to reboot.
On Wed, Nov 5, 2008 at 7:28 AM, <[EMAIL PROTEC
>The reason should be we are never going to unload the module. once the
>linux is shutdown its going to poweroff the cpu so no need to cleanup.
But what if there are some operations specified in the exit function of
module for cleaning up, which is specific to the module e.g. flushing some
module
Hey Sri,
can you send over the attached document?
Thanks
On Tue, Oct 14, 2008 at 10:13 AM, Sri Ram K Vemulpali
<[EMAIL PROTECTED]>wrote:
> Thank you Dhaval. Seems to be very good explanation of boot process and
> architecture. I will look in to it.
>
> Sri
>
> On Tue, Oct 14, 2008 at 2:33 AM, Dh
try this -
http://www.codesourcery.com/gnu_toolchains/arm
Thanks
On Sun, Aug 24, 2008 at 8:35 PM, Roman Mashak <[EMAIL PROTECTED]> wrote:
> Hello,
>
> 2008/8/24 Om Narasimhan <[EMAIL PROTECTED]>:
> > http://mirror.switch.ch/ftp/mirror/eldk/eldk/4.1/
> >
> > has (2) ARM tool chains. libc and ucli
It is head.S.
Depending on the arch which you have built your kernel for, head.S for that
corresponding arch is the starting place.
- A
On 6/13/08, Mohamed Thalib .H <[EMAIL PROTECTED]> wrote:
>
> Thanks Mulyadi.
> -
> Best Regards,
> Mohamed Thalib .H
> GDA Technologies
> L&T InfoTech Park,
>
Thanks guys!
On Thu, Jun 12, 2008 at 12:15 PM, Johannes Weiner <[EMAIL PROTECTED]>
wrote:
> Hi,
>
> "sahlot arvind" <[EMAIL PROTECTED]> writes:
>
> > Guys,
> >
> > 1. If I allocate a page of memory through kmalloc () inside my driver
> th
Guys,
1. If I allocate a page of memory through kmalloc () inside my driver then
are there chances in future that this page might get swapped out? I mean as
in kernel pages never get swapped out so I am bit confused if kmalloc'd
pages are candidate for being swapped out or not?
2. Similiar to 1.
I am trying to understand how can I read the pte using pte_page. Please
could you explain?
On 5/28/08, Cédric Augonnet <[EMAIL PROTECTED]> wrote:
>
> 2008/5/28 sahlot arvind <[EMAIL PROTECTED]>:
> > I am working on Linux 2.6 and inside the init function of my mo
I am working on Linux 2.6 and inside the init function of my module I am
doing this -
-
init_module ()
{
va = kmalloc (4096, GFP_KERNEL);
}
--
Now I want to read the page table entry for this va?
What is the right way to do that?
Thanks in advance
- A
Hello
Do kernel threads have different address space like User processes have? I
mean if I allocate some memory in kernel thread A then can kernel thread B
see it or can some driver see it?
Thanks in advance
- A
I want to learn Linux Kernel Programming. I have books like Understanding
the Linux Kernel, Linux Kernel Development and The Linux Kernel Module
Programming, but I don't know how to start. Should I play with my existing
Kernel or should I install another Linux using Virtualization?
IMO installing
AIL PROTECTED]> wrote:
>
> Let me try
>
> On Sun, Apr 27, 2008 at 7:56 PM, sahlot arvind <[EMAIL PROTECTED]> wrote:
> > What is the actual difference between Fix-mapped linear addresses and
> linear
> > addresses of kernel mapped in the first part of 4th GB of memory?
Kernel maps first part of 4th GB of memory using PAGE_OFFSET, while upper
128 MB of this 4th GB is left unmapped and is used for Fix-Mapped linear
addresses and non-contiguous memory allocation.
What is the actual difference between Fix-mapped linear addresses and linear
addresses of kernel mapped
I understand that at 'and' instruction it is actually preserving mode bits
as offset in the table immediately following this code. But why we are using
such a trick? Are we getting some kind of optimization by doing so?
On Sat, Apr 26, 2008 at 4:23 PM, sahlot arvind <[EMAIL PROT
I think that for the first go *Linux Kernel Development* by Robert Love
would be the best alternative. Once you get the overview you can go for
mmore detailed and advanced books.
- A
On Sun, Apr 27, 2008 at 1:54 AM, Adrian Bunk <[EMAIL PROTECTED]> wrote:
> On Sun, Apr 27, 2008 at 04:46:36AM +090
Thanks Robert.
I have 3rd edition as well. But it doesnt help much. One and the same story.
On Sun, Apr 27, 2008 at 12:00 AM, Robert P. J. Day <[EMAIL PROTECTED]>
wrote:
> On Sat, 26 Apr 2008, sahlot arvind wrote:
>
> > I am trying to understand linux memory management stuff
I am trying to understand linux memory management stuff. I am reading
Understanding Linux Kernel - 2nd Edition. I am at chapter 2 only and I am
confused like anything.
It says that kernel uses 3-level paging. In case of PAE is enabled it
actually uses page middle directory. My question is when IA-3
re question why do we have 16 handlers in each exception stub? why
not just 1 (e.g. __irq_svc) or 2 (__irq_usr and __irq_svc)? and what is use
of __irq_usr?
I am sorry I have put lot of questions in this email. But answers to them
would really help me in understanding the code.
Thanks in advance
Thanks Russell. I will re-try and get back in case dont understand.
- A
On Sat, Apr 26, 2008 at 2:09 AM, Russell King - ARM Linux <
[EMAIL PROTECTED]> wrote:
> On Fri, Apr 25, 2008 at 02:31:20PM +0530, sahlot arvind wrote:
> > Guys,
> >
> > I am trying to understand
Where do we jump after executing 'b
vector_irq + stubs_offset'?
Thanks
On 4/25/08, eric miao <[EMAIL PROTECTED]> wrote:
>
> On Fri, Apr 25, 2008 at 5:01 PM, sahlot arvind <[EMAIL PROTECTED]> wrote:
> > Guys,
> >
> > I am trying to understand the flow of
>Now a new process is loaded to memory, which utilizes a .so already in
memory. How does ld.so know if the required .so is already in >memory and
what is its physical address?
I think loader keeps track of which libraries are there in the memory and
their location. Execuatble file of the program c
Guys,
I am trying to understand the flow of control when an interrupt comes.
I am reading linux-2.6.24 src code and looking at
arch/arm/kernel/entry-armv.S.
At the bottom of this file I see the vector table as below -
__vectors_start:
swi SYS_ERROR0
b vector_und + stubs_offset
ldr p
u, Apr 24, 2008 at 7:05 PM, Robert P. J. Day <[EMAIL PROTECTED]>
wrote:
> On Thu, 24 Apr 2008, sahlot arvind wrote:
>
> > Yes. I agree with Robert. There are two stacks per process. But why
> > cannot we just use one stack as I said earlier?
>
> while there may be other rea
Yes. I agree with Robert. There are two stacks per process. But why cannot
we just use one stack as I said earlier?
- A
On 4/24/08, Robert P. J. Day <[EMAIL PROTECTED]> wrote:
>
> On Thu, 24 Apr 2008, dinesh bansal wrote:
>
> > AFAIK there is only one kernel stack and all the processes share
> >
Why do we have two stacks per process i.e. one user mode and other kernel
mode?
As soon as process enters into kernel mode it starts using kernel mode
stack, but as soon as it comes out of kernel mode stack there is nothing in
the kernel mode stack. So cannot we simply have a single stack i.e. just
I think what you are looking for is implemented in C library.
Look into the C lib code for fork implementation.
- A
On 4/22/08, Michael Kerrisk <[EMAIL PROTECTED]> wrote:
>
> On Mon, Apr 21, 2008 at 10:18 PM, Michael Kerrisk
> <[EMAIL PROTECTED]> wrote:
> > On Mon, Apr 21, 2008 at 10:06 PM, Mich
Ok. My turn -
User Process - There is nothing like kernel process. Its just user process,
which sometimes executes in user mode and sometimes in kernel mode.
User Thread - Linux doesnt have the concept of thread. It does not implement
threads separately. Thread is just a process for linux. However
the real kernel developers do that? how do they verify the code?
> How if we wanne to debug the filesystem interface and some char driver
> interfaces like ttys etc.
>
> Regards,
> Mukund Jampala
>
>
> On 4/12/08, sahlot arvind <[EMAIL PROTECTED]> wrote:
> > This mu
This much should be enough. Try to look into the source code as well. You
might not understand at this stage but just get a feel of it, that should be
fine.
Some part of any operating system is h/w specific and thus stick with one
arch at this stage e.g. x86 or ARM.
Understanding Linux kernel talks
Dear Bhanu,
Let me put it into simple words.
If you want to protect a write operation such as "a++" where "a" is global
variable of your program/module (i.e. it is manipulated by your code only)
then please use write semaphore. You will play safe.
Otherwise if "a" is a variable inside kernel and
Bhanu,
I think your question is -
If user thread UT1 is trying to read some data (through sys call because you
cannot access kernel data directly), which is modifiable by kernel thread
KT1 then along with the protection of your critical section(where you are
reading the data) the data, which KT1 m
True. but I think before start_kernel what comes into picture lies in head.S.
Of course it is arch specific.
Thus the actual start up code is in head.S -
for i386 it is arch/i386/kernel/head.S
for ARM it is arch/arm/kernel/head.S
AFAIK from there onwards control jumps to start_kernel () in init/
Its working now.
I ran uml in one terminal and from other i attached gdb to uml process.
it worked.
A
On Wed, Mar 26, 2008 at 4:50 PM, sahlot arvind <[EMAIL PROTECTED]> wrote:
> Hi Guys,
>
> I am learning how to debug the kernel using UML.
> I am doing the following
Hi Guys,
I am learning how to debug the kernel using UML.
I am doing the followings -
$gdb linux
..
..
(gdb)set args ubda=rootfs mem=128M
(gdb)r
..
..
Now onwards linux runs properly and I get the command prompt.
At this point when linux is running fine, what should I do to stop the
kernel? I mea
just to add -
Linux Kernel development by Robert Love would be the best i guess.
On Wed, Mar 12, 2008 at 9:41 AM, ANOOP <[EMAIL PROTECTED]> wrote:
>
>
> On Wed, Mar 12, 2008 at 9:12 AM, vasant j <[EMAIL PROTECTED]> wrote:
> > Hi i am kernel newbie ,kindly suggest me any linux pdf or book to start
Hi Folks,
Any mailing list for Cryptography in Linux e.g. any mailing list for Open
Source lib implementation of PKCS #11 in linux.
Thanks
- A
Thanks a lot man!
On 2/11/08, Manish Katiyar <[EMAIL PROTECTED]> wrote:
>
> On Feb 11, 2008 1:07 PM, sahlot arvind <[EMAIL PROTECTED]> wrote:
> > The reason I asked is because I dont have much knowledge of UML.
> > Can you give me some pointers/links to learn
The reason I asked is because I dont have much knowledge of UML.
Can you give me some pointers/links to learn about this? Can we do source
level debugging on UML?
Thanks
On 2/11/08, Manish Katiyar <[EMAIL PROTECTED]> wrote:
>
> On Feb 11, 2008 1:00 PM, sahlot arvind <[EMAIL PR
Your welcome!
Just a question - what is your environment?
Are you using some system emulator? what looks to me is that you are running
User Mode Linux?
On 2/11/08, Manish Katiyar <[EMAIL PROTECTED]> wrote:
>
> On Feb 11, 2008 12:45 PM, sahlot arvind <[EMAIL PROTECTED]> wr
You can ask your questions here itself. I guess.
On 2/11/08, Manish Katiyar <[EMAIL PROTECTED]> wrote:
>
> Hi,
>
> Anyone aware of any file system specific mailing lists for newbies.
> All I know of linux-fsdevel (this is not suitable for newbies :-(
> questions ) and some mailling lists for speci
ulyadi Santosa <[EMAIL PROTECTED]> wrote:
>
> Hi...
>
> On 2/5/08, sahlot arvind <[EMAIL PROTECTED]> wrote:
>
> > TLB entries are filled by H/W and not explicitly by kernel. Whenever MMU
> > translates VA to PA it caches that translation into TLB. If TLB is f
> E.g. who fills, flushes & refills the TLB entries?
TLB entries are filled by H/W and not explicitly by kernel. Whenever MMU
translates VA to PA it caches that translation into TLB. If TLB is full then
MMU uses its own algorithms to replace some entry in TLB e.g. MMU might
consider TLB as circular
And one more question - can we load linux image any where in the memory and
run?
Thanks
- A.
On 1/24/08, Rene Herman <[EMAIL PROTECTED]> wrote:
>
> On 24-01-08 14:02, sahlot arvind wrote:
>
> > That makes sense. Thanks a lot. So position independent code is one
> > whe
" that is
>relevant and not any absolute values.
That makes sense. Thanks a lot. So position independent code is one wherein
all the branch instructions are PC relative. Right?
And is the entire Linux Kernel Position Independent Code???
Thanks
- A.
On 1/24/08, Rene Herman <[EMAIL PROTECT
It is called when we insert the FS module. But as you have compiled ext3
module along with kernel then I think register function gets called during
boot process.
On 1/24/08, Onkar <[EMAIL PROTECTED]> wrote:
>
> I compiled the kernel with CONFIG_EXT3_FS=y ; having done that now , do
> these func
I compiled kernel for ARM processor.
I am trying to trace kernel control flow. I am looking at file
"arch/arm/kernel/head.S" . Code starting with
---
__INIT
.type stext, #function
ENTRY(stext)
mov r12, r0
mov r0, #PSR_F_BIT | PSR_I_BIT | MO
/24/08, sahlot arvind <[EMAIL PROTECTED]> wrote:
>
> >And, memory allocated by pages are considered "kernel memory". So
> >unless you mark them somehow, there is no difference between the ones
> >allocated by module, syscall and so on.
>
> Makes sense!
> T
memory is lost and kernel wont be able to use that memory in
future. Right?
On 1/24/08, Mulyadi Santosa <[EMAIL PROTECTED]> wrote:
>
> Hi...
> On Jan 24, 2008 1:32 PM, sahlot arvind <[EMAIL PROTECTED]> wrote:
> > Thanks to all for their resonse!
> >
> > O
Thanks to all for their resonse!
Ok, just one thing -
When I do lsmod -
it shows the memory used by loaded LKMs. So if there is a leak in LKM1 then
after executing the function (which is doing kmalloc but forgetting to do
kfree) of LKM1, lsmod should report an increased memory usage by LKM1. Am I
Some links, which I referred to -
http://www.coda.cs.cmu.edu/doc/talks/linuxvfs/
http://www.atnf.csiro.au/people/rgooch/linux/vfs.txt
Though I am not expert.
Thanks
On 1/23/08, Li Xiaodong <[EMAIL PROTECTED]> wrote:
>
> I think source code is the best material for you.
>
> You can also read s
I have written a simple LKM. I just want to test whether there is a memory
leak in the module or not?
Could any body suggest me how to test the memory leakage in LKM?
Thanks
- A.
;
> please refer this link
> http://kernelnewbies.org/FAQ/asmlinkage
>
>
> On Jan 16, 2008 5:05 PM, Mulyadi Santosa < [EMAIL PROTECTED]>
> wrote:
>
> > Hi
> >
> > On Jan 16, 2008 6:27 PM, sahlot arvind < [EMAIL PROTECTED]> wrote:
> > > I am seei
I am seeing lot of funtions prefixed with "asmlinkage".
Shall I assume that any defined function prefixed with "asmlinkage" is
System Call?
BTW what is "asmlinkage"?
Thanks
- A.
Thanks for your response!
What is PAGE_OFFSET at 3GB on x86,?
As you said PA to VA is found by subtracting PAGE_OFFSET, that means it is
not like
PA = VA. Right?
On 1/11/08, Mahaveer Darade <[EMAIL PROTECTED]> wrote:
>
>
>
> On Jan 11, 2008 10:57 AM, sahlot arvind <[EM
Hi All,
I just started learning Linux Virtual Memory Management Subsystem.
I see the memory is divided into three zones. Comments in file mm/mmzone.h
/*
* ZONE_DMA < 16 MB ISA DMA capable memory
* ZONE_NORMAL 16-896 MB direct mapped by the kernel
* ZONE_HIGHMEM > 896 MB
Thanks buddy!
I will ask further if needed.
Cheers!
Arvind
On Dec 26, 2007 7:43 PM, Thomas Petazzoni <[EMAIL PROTECTED]> wrote:
> Le Mon, 24 Dec 2007 22:32:25 +0530,
> "sahlot arvind" <[EMAIL PROTECTED]> a écrit :
>
> > Could any body help me in setting up m
In kernel/fork.c -
In function do_fork (), i see that we allocate some pidmap.
Could someone please tell me -
what is pidmap ?
what is its use?
Thanks
- A
amp;mylist;
printf ("hi\n");
if (i)
INIT_LIST_HEAD(ptr);
else
{
printf ("jkldkas\n");
}
return 0;
}
--
Got the reason why while (0) is there.
Thanks man!
- Arvind
On 12/26/07, sahlot arvind <[EMAIL PR
ntf ("hi\n");
if (i)
{
INIT_LIST_HEAD(ptr);
}
else
{
printf ("jkldkas\n");
}
return 0;
}
--
And there is no compilation error.
On 12/26/07, Li Zefan <[EMAIL PROTECTED]> wrote:
>
> sahlot arvind wrote:
Recently I started looking into linux kernel and trying to understand the
code.
I am working with linux-2.6.9.
in file include/llinux/list.h - I found something like this.
#define INIT_LIST_HEAD(ptr) do { \
(ptr)->next = (ptr); (ptr)->prev = (ptr); \
} while (0)
My question is why do we
>#include
>#include
>intexterint[5][5];
>intexterint1[5];
>int main(void){
>int index0, index1;
>int **temp1;
>int *temp2;
>temp2=exterint1; //*
>temp1 = exterint; //x
>The compiler will warn me that at line marked as x is "assignment from
incompatible pointer type."
>But "
printf is a libarary function, while printk is implemented in kernel itself
since kernel doesnt use library functions.
printf displays on STD output, while printk logs the messages and kernel log
demon displays that content on the screen.
Apart from this, you can also pass the priority of the messa
points because the first step is a very daunting task and you are
> much more likely to keep at it if you are learning about something you are
> truly interested in.
>
>
>
> Cheers
>
> Al
> ------
>
> *From:* [EMAIL PROTECTED] [mailto:
> [E
Hi All,
I am new to Linux kernel. Could any body suggest me where to start reading
the source code?
OR
I first should read some books?
best regards
Hi All,
I am new to the kernel newbies list. I want to learn linux kernel code but
finding it difficult to start from.
Let me explain, if for example I have to understand a program then what I
will do is, I will find out the main function and start analyzing the code
and understand the flow and en
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