remap_page_range

remap_page_range

[Thiago Robert dos Santos]

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All,

  I'm having a problem with remap_page_range in the 2.6 kernel series. I
use remap_page_range inside the mmap function of a module I wrote in
order to map a given device's memory into user space.

  Apparently, everything works fine but I just can't access the device's
memory (even tough I get a valid point from the mmap system call). This
is the mmap function I wrote:


static int
pcimap_mmap (struct file *filp, struct vm_area_struct *vma)
{

    int unit, reg;
    unsigned long size, phy_addr;

    unit = MINOR(filp->f_dentry->d_inode->i_rdev) >> 4;
    reg = MINOR(filp->f_dentry->d_inode->i_rdev) & 0x0f;

    size = vma->vm_end - vma->vm_start;

    /* Mapping must be page aligned and not larger than the region size */
    if ((size + vma->vm_pgoff * PAGE_SIZE) > pcidevs[unit].reg[reg].size)
    {
        return -EINVAL;
    }

    /* Get device's memory physical address for mapping */
    phy_addr = pcidevs[unit].reg[reg].phy_addr + vma->vm_pgoff * PAGE_SIZE;

    /* Map device's memory in the requested address space range */
    if (remap_page_range (vma, phy_addr, 0, size, vma->vm_page_prot))
    {
        return -EAGAIN;
    }

    filp->f_dentry->d_inode->i_count.counter++;

    return 0;
}



    Can anyone help me?


Thanks in advance.


Thiago Robert

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Re: remap_page_range

[William Lee Irwin III]

On Wed, Nov 17, 2004 at 06:43:46PM -0200, Thiago Robert dos Santos wrote:
>   I'm having a problem with remap_page_range in the 2.6 kernel series. I
> use remap_page_range inside the mmap function of a module I wrote in
> order to map a given device's memory into user space.
>   Apparently, everything works fine but I just can't access the device's
> memory (even tough I get a valid point from the mmap system call). This
> is the mmap function I wrote:
> static int
> pcimap_mmap (struct file *filp, struct vm_area_struct *vma)
> {

(1) set PG_reserved on all struct pages covering the physical region
(2) set VM_RESERVED|VM_IO in vma->vm_flags


-- wli