Hi!
I changed remap_pfn_range with vma_insert_page and it works perfectly!
Ive to find out what caused the pbm tho
Thanks,
Sudharsan
On 10/31/06, Anumolu Sudheer <urwithsudheer@xxxxxxxxx> wrote:
On 10/31/06, Sudharsan Rangarajan <sudharsan.r@xxxxxxxxx > wrote:
> Hi all,
> I have been trying to map memory to user space, but i get a strange
problem.
> Heres a kmsg dump
> <1>Hello
> <1>Success!
> <1>Alloc memory now
> <1>Virtual address of region alloced using kmalloc : d79ec000
> <1>I'm ok!
> <1>Virtual address of region alloced using kmalloc : d79ec000
> <1>Physical address of region alloced using kmalloc : 179ec000
> <1>VMA start for process : b7f22000
> <1>VMA end for process : b7f23000
> <1>Bye
>
> and heres the code for allocating the memory area
> base=kmalloc(PAGE_SIZE,GFP_KERNEL);
> *base='a';
> printk ("<1>%x",base);
> mem_map_reserve(virt_to_page(base));
Please check trying with
SetPageReserved(virt_to_page(virt_addr));
> Heres the mmap code..It succeeds the dump doesnt say failed
>
> unsigned long page,pos,basepos;
> pos=(unsigned long) base;
> printk ("<1>%x",pos);
> page = virt_to_phys((void *)pos);
> printk ("<1>%x",page);
> printk ("<1>%x",vma->vm_start);
> printk ("<1>%x",vma->vm_end);
> if (remap_pfn_range(vma,vma->vm_start, page >>
PAGE_SHIFT,
Is a PAGE_SHIFT necessary here ??
Regards
Sudheer
> vma->vm_end-vma->vm_start, vma->vm_page_prot))
> {
> printk ("<1>failed");
> return -EAGAIN;
> }
> return 0;
>
> Heres a gdb dump for the process
>
> Breakpoint 1, main () at userapp.c:21
> (gdb) print p
> $1 = 0xb7f22000 <Address 0xb7f22000 out of bounds>
> (gdb) quit
>
> This is btw a character device..
> i do
> int fd=open("....",O_RDONLY);
> char *p = ( char *) mmap(NULL, 1024, PROT_READ,MAP_SHARED,fd,0);
>
> All the calculations seem right...and remap was called with 0xb7f22000 as
> the base to mmap..But the app complains that the page tables arent right!
> I did a pagetable walk for vma->vm_start in current->mm and the
> physical address was right! What could be the problem?
>
> Thanks,
> Sudharsan
>
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