virtual-address-space Questions
3
remap_pfn_range function (used in mmap call in driver) can be used to map kernel memory to user space. How is it done? Can anyone explain precise steps? Kernel Mode is a privileged mode (PM) while ...
Perdure asked 9/1, 2012 at 12:15
1
When I want to mark memory region as Write Combined (to disable cacheable and use BIU) or Uncacheable through set PAT(Page attribute table - 7bit in PTE), then what do I must to use, and what is th...
Cedell asked 6/11, 2013 at 11:43
3
I have started to learn about Virtual Address Space (VAS) and I have few questions:
How much of VAS is created for each process depending on the architecture (32-bit and 64-bit)?
Is VAS for each p...
Congregationalist asked 6/12, 2020 at 17:8
13
Just reading some notes in a purdue lecture about OSs, and it says:
A program sees memory as an array of
bytes that goes from address 0 to 2^32-1 (0 to
4GB-1)
Why 4 GB?
Internal asked 13/7, 2009 at 12:55
3
Solved
During reading of an Intel manual book I came across the following:
On processors that support Intel 64 architecture, the IA32_SYSENTER_ESP field and the IA32_SYSENTER_EIP field must each contai...
Tantalus asked 15/9, 2014 at 16:11
6
Solved
I have taken a course about Operating System design and concept and now I am trying to study Linux kernel thoroughly. I have a question that I cannot get rid of. In modern operating systems each pr...
Metrorrhagia asked 8/8, 2010 at 18:54
5
Is there any API for determining the physical address from virtual address in Linux operating system?
Juanjuana asked 21/4, 2011 at 18:52
7
Solved
On Windows, under normal circumstances a 32 bit process can only access 2GB of RAM (or 3GB with a special switch in the boot.ini file). When running a 32 bit process on a 64 bit operating system, h...
Bullough asked 12/3, 2009 at 17:0
1
The following image shows where the sections of a process are laid out in the process's virtual address space (in Linux):
You can see that there is only one stack section (since this process onl...
Galatia asked 1/7, 2017 at 7:36
1
Solved
Intel and AMD documentation says that for 64 bit mode only 48 bits are actually available for virtual addresses, and bits from 48 to 63 must replicate bit 47 (sign-extension). As far as I know, all...
Chante asked 9/9, 2016 at 16:35
2
Solved
As known: http://linux.die.net/man/3/malloc
By default, Linux follows an optimistic memory allocation strategy.
This means that when malloc() returns non-NULL there is no guarantee
that the me...
Magnanimous asked 25/7, 2016 at 12:49
1
Solved
I have an executable file, and a gcore.
I created core dump file with gcore.
Now, I would like to map the virtual address of the executable file to the core dump.
I know that the core dump is a ...
Ayesha asked 28/8, 2015 at 13:43
2
Solved
I'm having some difficulty understanding how the OS passes data from the address space of a parent process to the address space of a child process. Namely, in a C program, where is argc and argv st...
Huffman asked 17/10, 2014 at 1:49
2
I read that , "When a program executes an instruction like : MOV REG,1000 , it does so to copy the contents of the memory address 1000 to REG. Address can be generated using indexing,base registers...
Breaststroke asked 23/2, 2012 at 14:4
1
Solved
For a win32 executable (x86) we can set the LargeAddressAware flag so it can access a virtual address space of 4 GB (instead of just 2 GB) when running on x64 Windows.
This looks very appealing. Ho...
Norvol asked 16/4, 2014 at 15:40
2
Solved
I am attending an OS course, wherein the instructor mentions 32 v/s 64 bit architectures.
My understanding of this difference from my architecture class is that 32 bit v/s 64 bit indicates the CPU ...
Virility asked 12/4, 2014 at 21:45
3
Solved
We need to link one of our executables with this flag as it uses lots of memory.
But why give one EXE file special treatment. Why not standardize on /LARGEADDRESSAWARE?
So the question is: Is there...
Nodababus asked 18/2, 2010 at 13:1
2
Solved
I've been learning these topics and read many articles and books but they all lack some complementary information and confused me even more. So here, I’d like to explain what I know while I am aski...
Recapitulate asked 10/3, 2014 at 0:51
2
Solved
I would like to disable address space layout randomization (ASLR) on my system (Ubuntu Gnu/Linux 2.6.32-41-server), but, if I use
sysctl -w kernel.randomize_va_space=0
the change would affect al...
Protasis asked 28/6, 2012 at 5:17
1
Solved
All the drivers in the Linux running in the same context (address space of the kernel-space), or each in a different (similar to how the different processes work in a different address spaces in us...
Centreboard asked 22/11, 2013 at 10:21
1
Solved
Which addressing is used in processors x86/x86_64 for caching in the L1, L2 and L3(LLC) - physical or virtual(using PT/PTE and TLB) and somehow does PAT(page attribute table) affect to it?
And is ...
Toscana asked 26/9, 2013 at 21:46
3
Solved
I am developing a C# program that will load files and get information such as loaded file created date, modification date, size etc. Another thing that I need to know is whether the loaded file (ex...
Hoofbound asked 29/1, 2012 at 15:51
4
Solved
I'm having simple code as follows:
#include<stdio.h>
int glob;
int main(void)
{
int a;
printf("&a is : %p \n", &a);
printf("glob is : %p \n", &glob);
return 0;
}
Output o...
Franciscafranciscan asked 5/4, 2013 at 11:53
1
Solved
I've an address in memory and I want to find out the permissions (r/w/x) of that memory address.
E.g.
char *s = "hello";
Here, the string literal "hello" is stored in read-only memory. When run...
Powell asked 28/5, 2012 at 6:55
2
Solved
Example question from a past operating system final, how do I calculate this kind of question?
A computer has a 64-bit virtual address space and 2048-byte pages. A page table entry takes 4 bytes. ...
Utricle asked 5/4, 2011 at 21:40
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