Error accessing memory between 0xc0000 and 0x100000

From: Edgardo Hames (ehames@scdt.frc.utn.edu.ar)
Date: Tue Mar 25 2003 - 11:08:36 EST

Hi everybody. I'm trying to write a simple device driver to read and write
memory at addresses beween 0xc0000 and 0x100000, but when I try to load the
module I get the following error:

memalloc: successful request base=0xd0000, size=0x10000
Unable to handle kernel paging request at virtual address 000d0001
 printing eip:
c182b0b6
*pde = 00000000
Oops: 0002
CPU: 0
EIP: 0010:[<c182b0b6>] Not tainted
EFLAGS: 00010282

EIP is at (2.4.18diskless)
eax: 000d0000 ebx: 00010000 ecx: c026fed8 edx: 00000000
esi: 00000000 edi: 00000000 ebp: c058bf28 esp: c058bf10
ds: 0018 es: 0018 ss: 0018
Process insmod (pid: 220, stackpage=c058b000)
Stack: c182b160 000d0000 00010000 c182b130 00000000 c182b000 0806a810 c01159f5
       00000000 c07a2000 00000220 c07a5000 00000060 ffffffea 00000008 c0638640
       00000060 c1819000 c182b060 000005a4 00000000 00000000 00000000 00000000
Call Trace: [<c182b160>]
[<c182b130>]
[<c01159f5>]
[<c182b060>]
[<c0108ac3>]

Code: c6 40 01 41 83 c4 10 eb 1d 90 50 53 ff 35 9c b5 82 c1 68 a0

Can you help me out, please? Here is the code for my driver:
/***************************** DRIVER CODE ******************************/
int major = 0;
MODULE_PARM(major, "i");

unsigned long isa_base = 0xc0000;
MODULE_PARM(isa_base, "l");

unsigned long isa_max = 0x100000;
MODULE_PARM(isa_max, "l");

MODULE_AUTHOR("Edgardo Hames");
MODULE_LICENSE("GPL");

//#define BUFFER "Hello, world!"

int memalloc_init(void)
{
        int result = 0;
        unsigned long region_size = isa_max - isa_base;

        if (! check_mem_region(isa_base, region_size)) {
                request_mem_region(isa_base, region_size, "memalloc");
                printk("memalloc: successful request base=0x%lx, size=0x%lx\n",
                        isa_base, region_size);
// isa_memcpy_toio(isa_base, BUFFER, strlen(BUFFER));
                writeb ('A', isa_base+1);
        } else {
                printk("memalloc: failed request base=0x%lx, size=0x%lx\n",
                        isa_base, region_size);
                return -EBUSY;
        }
        return result;
}

void memalloc_cleanup(void)
{
//#define BUFSIZE 100

        unsigned long region_size = isa_max - isa_base;
// char buf[BUFSIZE];
        
// memset(buf, 0, BUFSIZE);
// isa_memcpy_fromio(buf, isa_base, BUFSIZE);
        printk("Leí: %c\n", readb(isa_base+1));
        release_mem_region(isa_base, region_size);
        printk("Successfully unloading memalloc.\n");
}

module_init(memalloc_init);
module_exit(memalloc_cleanup);

/************************* END OF DRIVER CODE **************************/

Thanks
Ed 

-- 
If you cannot convince them, confuse them.
Truman's Law

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This archive was generated by hypermail 2b29 : Mon Mar 31 2003 - 22:00:20 EST