linux-kernel - Fwd: Problem with set_memory

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Date:	Thu, 4 Feb 2010 10:09:57 +0200
From:	Oleg Kutkov <elenbert@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Fwd: Problem with set_memory_rw

set_memory_rw()'s 1st argument requires virtual address.
So, you need virtual address of the page you want.

 - phys_to_virt() ... convert physical address to virtual address.
 - virt_to_phys() ... convert virtual address to physical.

Anyway, RW is vitual address mapping's attribute and not for physical.

Thanks,
-Kame

Thank for answer!
But this is a very strange, because 0x0509940 - it a virtual memory
address (i got it from System.map, this is a system call table, on my
machine). set_memory_rw return zero, anyway. Maybe, system call table
is much write protected, so i can't change attribute of memory page?
One more interesting thing:

struct page *pg;
pg = virt_to_page(addr);
unsigned long page_addr;
page_addr = (unsigned long) page_address(pg);

addr - this is my virtual address (provided by System.map)
But page_addr got another value!
What wrong?
Sorry, if my questions is to stupid.

P.S. I know, that overwriting system call table is very bad, i just
experimenting with my own network drivers and i need to replace some
network system calls..

Best regard,
Oleg.
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