hello... > but what is the KERNEL's virtual memory ? well, it is virtual memory too..only, the pages which is mapped in this area has Supervisor flag set...so it can be accessed only in kernel mode (CPL--Current Privilege Level 0) > how come the kernel has a virtual memory, too ? like a process ? because kernel (after init stage is passed and fully operated) works in x86 protected mode (here we talk strictly about x86). every memory access is done via this phase: logical address-->virtual addr--> physical So, in other word, if kernel try to access memory in protected mode, it issues virtual address...and MMU will translate it into physical address. Virtual memory itself is a result of segmentation plus paging....two basics mechanism that provides clue to MMU on how to turn virtual address into physical address. And yes, kernel do have its own page table...it is referred by so called "master kernel page global directory"...this is the same page tables that define the upper (>3GB) process address space (in 3G/1G VM split). It is built on early phase of kernel init. Check out startup_32(). > what does the /dev/kmem show ? IIRC, it shows kernel virtual memory content....if you look at phrack.org's article, you will see numerous articles there mentioning "tricks" on how to use it...ranging from "good" to "very nasty" intention... :) > isn't the kernel just a bunch of asynchronous functions, > working without a memory descriptor ? What do you mean by "without memory descriptor"? regards Mulyadi -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
