Re: Kernel Virtual Address
- From: "Mozis" <chokshi.jaydeep@xxxxxxxxx>
- Date: 29 Jan 2006 07:59:43 -0800
Every logical address in kernel mode is kernel virtual address but
every kernel vitual address may not be a logical address.
Kernel logical addresses are those which have direct mapping to phyical
RAM (might be at constant PAGE_OFFSET), they are for whome kernel
builds the page table at boot time.They are also called as Linear
address.
Now the high memory address are not directly mapped in (above the 896
MB), kernel has to make page table for them in order to make available
them, these addresses are called logical address. alloc_pages(..) can
returns those address. Internally kernel makes use of kmap(..) &
kunmap(..) to map them.
Even ioremap(..) also builds the page table for pci mapped address.
So there are two types,
1. linear address
2.logical address
both are kernel virtual address, but with difference.
Ofcourse there are other address called Bus address but its nt a issues
in this thread.
Regards,
Mozis.
.
- References:
- Kernel Virtual Address
- From: amit
- Re: Kernel Virtual Address
- From: Peter T. Breuer
- Kernel Virtual Address
- Prev by Date: Re: fopen: pre-pending text
- Next by Date: What is max cpu's for x86 in stock 2.6 kernel
- Previous by thread: Re: Kernel Virtual Address
- Next by thread: What is max cpu's for x86 in stock 2.6 kernel
- Index(es):
Relevant Pages
|
