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What is vDSO in kernel?
vDSO (virtual dynamic shared object) is a kernel mechanism for exporting a carefully selected set of kernel space routines to user space applications so that applications can call these kernel space routines in-process, without incurring the performance penalty of a mode switch from user mode to kernel mode that is …
What is vDSO Linux?
The “vDSO” (virtual dynamic shared object) is a small shared library that the kernel automatically maps into the address space of all user-space applications. This way you can code in the normal way using standard functions and the C library will take care of using any functionality that is available via the vDSO.
What is LDD in Linux?
Ldd is a Linux command line utility that is used in case a user wants to know the shared library dependencies of an executable or even that of a shared library. Library is a collection of resources such as subroutines/functions, classes, values or type specifications.
What does LDD mean?
LDD
| Acronym | Definition |
|---|---|
| LDD | Learning Difficulties and Disabilities |
| LDD | Land Development Division (various locations) |
| LDD | Limited Distribution Drugs (medication protocol) |
| LDD | Light Duty Detergent |
Where is Linux-vdso.so.1 present on the file system?
It’s a virtual shared object that doesn’t have any physical file on the disk; it’s a part of the kernel that’s exported into every program’s address space when it’s loaded. It’s main purpose to make more efficient to call certain system calls (which would otherwise incur performance issues like this ). The most prominent being gettimeofday (2).
Where is the libvdso library present in the file system?
I did a find for the libvdso library and there is no such library present in my file system. Where is the library present? It’s a virtual shared object that doesn’t have any physical file on the disk; it’s a part of the kernel that’s exported into every program’s address space when it’s loaded.
What’s the difference between vsyscall and vDSO in Linux?
The main difference between the vsyscall and vDSO mechanisms is that vDSO maps memory pages into each process in a shared object form, but vsyscall is static in memory and has the same address every time. For the x86_64 architecture it is called – linux-vdso.so.1.
Where does the initialization of the vDSO occur?
Initialization of the vDSO occurs in the init_vdso function that defined in the arch/x86/entry/vdso/vma.c source code file. This function starts from the initialization of the vDSO images for 32-bits and 64-bits depends on the CONFIG_X86_X32_ABI kernel configuration option: Both functions initialize the vdso_image structure.