Can kernel process access user address space ? Post: 302259394

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

How to find the size of Process Address space.

Hello, Please help me to know, How to find out the how much amount of process addres space is required/is used for/by a process. Tnx & Regards Vishwa.

2. Programming

Aplication user and kernel mode (data access)

Hi all, I am trying to setup a program to use a device driver and am confusing buffer access between User and Kernel mode. I think all applications running in User space have to communicate with the device drivers using io control calls and then have some functions called back from the driver...

3. HP-UX

How to restrict a user group to access the kernel

Hi, Please any one can help me to know that how we can restrict a user group to access the kernel at all.

4. Programming

Access process memory from kernel space

Hi, I'm currently working on a project to help the analysis of malware from inside the kernel to avoid any kind of detection. So I need to be able to read the process memory from my kernel module. As of now, I'm stuck at converting a virtual memory address (for example 0x080483e8 found...

5. Programming

Find Virtual address space size for process

Hi, I am looking to work on unix systems which include (hp-ux, ibm aix, solaris and linux). I want to get the total virtual address space of a process, the used virtual memory i am able to get without any problem. I have tried using getrlimit and getrlimit64, but that gives only ...

6. UNIX for Advanced & Expert Users

wake up user space thread from kernel space ISR

Hello, I'm searching for a proper way to let the kernel space ISR(implemented in a kernel module) wake up a user space thread on a hardware interrupt. Except for sending a real-time signal, is it possible to use a semaphore? I've searched it on google, but it seems impossible to share a...

7. Programming

How to get address space size that a process is allowed to use

Hi All, From C++, I just want to find the address space size that a process is allowed to use. For ex, in 32 bit OS the allowed address space is 4GB and in 64 bit OS I guess this is 16GB or more. I jsut want to find it in my C++ project. Is there any API calls that gives me such information....

8. UNIX for Dummies Questions & Answers

Kernel/ user space and high/ low mem

Need some clarification on this.... 1. how are kernel/ user spaces and high/low memory related? 2. What do they all mean when i have the kernel command line as: "console=ttyS0,115200 root=/dev/sda2 rw mem=exactmap memmap=1M@0 memmap=96M@1M irqpoll" or 2. what do mem and memmap mean in...

9. Programming

PC RAM and process address space

Suppose I have 3 gb of ram and 250 gb hard disk in my pc. Now I wrote a simple C program having only one statement malloc() to allocate 4 gb of memory as 32 bit os can address 4gb address space then will the malloc succeed? If yes then how it will get extra 1 gb of memory? Does the process gets...

10. UNIX for Advanced & Expert Users

Precaution to access user mode buffers from kernel

When accessing a user mode buffers from kernel space drivers what precautions must we take and how those precautions need to be implemented?

LEARN ABOUT OSF1

is_seg0_va

IS_KSEG_VA(9r)															    IS_KSEG_VA(9r)

NAME

       IS_KSEG_VA, IS_SEG0_VA, IS_SEG1_VA - General: Determine if the specified address is located in the kernel-unmapped address space, the user-
       mapped address space, and the kernel-mapped address space.

SYNOPSIS

       void IS_KSEG_VA(
	       unsigned long addr ); void IS_SEG0_VA(
	       unsigned long addr ); void IS_SEG1_VA(
	       unsigned long addr );

ARGUMENTS

       Specifies the virtual address.

DESCRIPTION

       The IS_KSEG_VA routine determines if the specified address is located in the kernel-unmapped address space. The IS_SEG0_VA  routine  deter-
       mines  if  the specified address is located in the user-mapped address space. The IS_SEG1_VA routine determines if the specified address is
       located in the kernel-mapped address space.

RETURN VALUES

       None

EXAMPLE

       The following code fragment shows a call to IS_KSEG_VA:

       .  .  .

       caddr_t virt_addr;  [1] unsigned phys_addr; [2]

       .  .  .

	   if(IS_KSEG_VA(virt_addr)) { [3]
	       phys_addr = KSEG_TO_PHYS(virt_addr); [4]

       .  .  .

       Declares a variable to store the user  buffer's	virtual  address.   Declares  a  variable  to  store  the  physical  address  returned	by
       KSEG_TO_PHYS.  Before calling KSEG_TO_PHYS, calls IS_KSEG_VA to determine if the virtual address is from the kernel-unmapped address space.
       If the virtual address is from the kernel-unmapped address space, then calls KSEG_TO_PHYS to convert the address to a corresponding  physi-
       cal address.

SEE ALSO

       Routines: KSEG_TO_PHYS(9r), PHYS_TO_KSEG(9r)

																    IS_KSEG_VA(9r)