ioremap - Unable to handle kernel paging request at virtual address XXXXXXXX

Question

I am attempting to access a given memory-region on an am335x-processor in Linux. The idea is to first designate physical addresses, then access said addresses using ioremap. I have been googling the issue for some time, but cannot seem to find any good solutions.

The functions to do these tasks are as follows:

Function to obtain physical addresses:

static int initPaddr(struct regref **reg, long unsigned int *base, int count)
{
    int i;

    reg = kmalloc(sizeof(struct regref*) * count, GFP_KERNEL);
    for(i = 0; i < count; i++)
        reg[i] = kmalloc(sizeof(struct regref), GFP_KERNEL);

    for(i = 0; i < count; i++)
        reg[i]->paddr = REG_ADDR(base, regArray[i]);

    return 0;
}

Function to register virtual addresses:

static int initVaddr(struct regref **reg, int blocksize, int count)
{
    int i;

    for(i = 0; i < count; i++)
        reg[i]->vaddr = (unsigned long*) ioremap( (unsigned long) reg[i]->paddr, blocksize);

    return 0;
}

Here regArray[] is just an array that hold all the relevant physical addresses and the struct regref is defined in the following way:

struct regref = {
    long unsigned int *paddr;
    long unsigned int *vaddr;
};

To code does compile, but when I try to load it, I end up getting the following error:

Unable to handle kernel paging request at virtual address 702f7373

Where the address may vary.

I assume I am doing something wrong, but fail to see exactly what that might be. Of course the code can be a lot better too, but I'd like to solve this issue before making further changes. Does anyone have any suggestions?

Answer 1

Turns out the mistake was not in the code above, but somewhere else. The code above is a working example for the use of ioremap().