bug in generic_access_phys (mm/memory.c) ?

[Paolo Minazzi]

Hi to all,
I think the function "generic_access_phys" in mm/memory.c has got a 
small bug.
THe ioremap_prot is called with the parameter size=PAGE_SIZE.
But it can happen that we need more than one page, and this will produce 
a kernel fault.

int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
                        void *buf, int len, int write)
{
        resource_size_t phys_addr;
        unsigned long prot = 0;
        void __iomem *maddr;
        int offset = addr & (PAGE_SIZE-1);

        if (follow_phys(vma, addr, write, &prot, &phys_addr))
                return -EINVAL;

====>   maddr = ioremap_prot(phys_addr, PAGE_SIZE);

        if (write)
                memcpy_toio(maddr + offset, buf, len);
        else
                memcpy_fromio(buf, maddr + offset, len);
        iounmap(maddr);

        return len;
}


I think that the ioremap_prot should be changed with

maddr = ioremap_prot(phys_addr, ((phys_addr + offset + len - 1) & 
~(PAGE_SIZE-1)) -
                                phys_addr + PAGE_SIZE);

Thanks,
Paolo Minazzi



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