Re: pte_val(*pte) as lvalue

[Timur Tabi <ttabi@interactivesi.com>]

Russell King wrote:

>Can I ask what the nature of the PTE modification is, and where you
>are making this modification?
>
I've written a hack which enables PAT (Page Address Translation) for a 
particular page:

void set_pte_pat(pte_t *pte, unsigned long pat_index)
{
    unsigned long p = pte_val(*pte);

    p &= ~(_PAGE_PROTNONE | _PAGE_PCD | _PAGE_PWT);    // zero-out the 
relevant bits

    if (pat_index & 4)
    p |= _PAGE_PROTNONE;

    if (pat_index & 2)
    p |= _PAGE_PCD;

    if (pat_index & 1)
    p |= _PAGE_PWT;

#if CONFIG_X86_PAE
    pte->pte_high = 0;
    pte->pte_low = p;
#else
    pte_val(*pte) = p;
#endif

-- 
Timur Tabi
Interactive Silicon