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What is kernel logical address?
Kernel logical addresses are mappings accessible to kernel code through normal CPU memory access functions. On 32-bit systems, only 4GB of kernel logical address space exists, even if more physical memory than that is in use. Logical address space backed by physical memory can be allocated with kmalloc .
Which address is logical address?
Logical and Physical Address in Operating System. Logical Address is generated by CPU while a program is running. The logical address is virtual address as it does not exist physically, therefore, it is also known as Virtual Address. This address is used as a reference to access the physical memory location by CPU.
Is logical address IP Address?
IP Address works at the network layer of OSI model (actually the IP layer of TCP/IP model). This is a logical address (and not the embedded hardware address) which is assigned by the Network administrator or Internet service provider. Hence IP address may change each time you connect with the Internet.
How much logical address space does the kernel have?
On 32-bit systems, only 4GB of kernel logical address space exists, even if more physical memory than that is in use. Logical address space backed by physical memory can be allocated with kmalloc. Virtual addresses do not necessarily have corresponding logical addresses.
How much memory is there in a kernel?
Kernel logical addresses are mappings accessible to kernel code through normal CPU memory access functions. On 32-bit systems, only 4GB of kernel logical address space exists, even if more physical memory than that is in use.
What’s the difference between virtual address and kernel virtual address?
In Linux device driver book it says that all logical address are kernel virtual address, and virtual address doesn’t have any linear mapping. But logically wise when we say it is logical and when we say virtual and in which situation we use these two ?
How is virtual address mapped to physical address in Linux?
The Linux kernel maps most of the virtual address space that belongs to the kernel to perform 1:1 mapping with an offset of the first part of physical memory. (slightly less then for 1Gb for 32bit x86, can be different for other processors or configurations). For example, for kernel code on x86 address 0xc00000001 is mapped to physical address 0x1.