问题
Considering Linux and 32 bit x86 arch there is 3:1 divide of the accessible 4GB address space. The user space is allocated 0-3 Gb while 3-4 Gb is allocated to kernel. How does a virtual address that is greater than 3Gb and hence lies into the kernel address space is transformed to the physical address? Does page tables would come into picture?
回答1:
There is some information in Mel Gorman's book Understanding the Linux Virtual Memory Manager.
The short answer: Yes, the kernel sets up page tables to translate physical address 0 to virtual address 3 GiB. (Section 3.7.1). This includes the physical location the kernel was loaded to (usually 1MB on x86).
来源：https://stackoverflow.com/questions/4826810/kernel-virtual-address-translation