/* Embedded type MMU with HW exec support. This is a bit more complicated
 * as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so
 * instead we "filter out" the exec permission for non clean pages.
 */
static pte_t set_pte_filter(pte_t pte)
{
	struct page *pg;

	/* No exec permission in the first place, move on */
	if (!(pte_val(pte) & _PAGE_EXEC) || !pte_looks_normal(pte))
		return pte;

	/* If you set _PAGE_EXEC on weird pages you're on your own */
	pg = maybe_pte_to_page(pte);
	if (unlikely(!pg))
		return pte;

	/* If the page clean, we move on */
	if (test_bit(PG_arch_1, &pg->flags))
		return pte;

	/* If it's an exec fault, we flush the cache and make it clean */
	if (is_exec_fault()) {
		flush_dcache_icache_page(pg);
		set_bit(PG_arch_1, &pg->flags);
		return pte;
	}

	/* Else, we filter out _PAGE_EXEC */
	return __pte(pte_val(pte) & ~_PAGE_EXEC);
}
Example #2
0
static pte_t set_pte_filter(pte_t pte, unsigned long addr)
{
	struct page *pg;

	
	if (!(pte_val(pte) & _PAGE_EXEC) || !pte_looks_normal(pte))
		return pte;

	
	pg = maybe_pte_to_page(pte);
	if (unlikely(!pg))
		return pte;

	
	if (test_bit(PG_arch_1, &pg->flags))
		return pte;

	
	if (is_exec_fault()) {
		flush_dcache_icache_page(pg);
		set_bit(PG_arch_1, &pg->flags);
		return pte;
	}

	
	return __pte(pte_val(pte) & ~_PAGE_EXEC);
}
Example #3
0
static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
				     int dirty)
{
	struct page *pg;

	if (dirty || (pte_val(pte) & _PAGE_EXEC) || !is_exec_fault())
		return pte;

#ifdef CONFIG_DEBUG_VM
	if (WARN_ON(!(vma->vm_flags & VM_EXEC)))
		return pte;
#endif 

	
	pg = maybe_pte_to_page(pte);
	if (unlikely(!pg))
		goto bail;

	
	if (test_bit(PG_arch_1, &pg->flags))
		goto bail;

	
	flush_dcache_icache_page(pg);
	set_bit(PG_arch_1, &pg->flags);

 bail:
	return __pte(pte_val(pte) | _PAGE_EXEC);
}
static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma,
				     int dirty)
{
	struct page *pg;

	/* So here, we only care about exec faults, as we use them
	 * to recover lost _PAGE_EXEC and perform I$/D$ coherency
	 * if necessary. Also if _PAGE_EXEC is already set, same deal,
	 * we just bail out
	 */
	if (dirty || (pte_val(pte) & _PAGE_EXEC) || !is_exec_fault())
		return pte;

#ifdef CONFIG_DEBUG_VM
	/* So this is an exec fault, _PAGE_EXEC is not set. If it was
	 * an error we would have bailed out earlier in do_page_fault()
	 * but let's make sure of it
	 */
	if (WARN_ON(!(vma->vm_flags & VM_EXEC)))
		return pte;
#endif /* CONFIG_DEBUG_VM */

	/* If you set _PAGE_EXEC on weird pages you're on your own */
	pg = maybe_pte_to_page(pte);
	if (unlikely(!pg))
		goto bail;

	/* If the page is already clean, we move on */
	if (test_bit(PG_arch_1, &pg->flags))
		goto bail;

	/* Clean the page and set PG_arch_1 */
	flush_dcache_icache_page(pg);
	set_bit(PG_arch_1, &pg->flags);

 bail:
	return __pte(pte_val(pte) | _PAGE_EXEC);
}
Example #5
0
/* Other embedded CPUs with HW exec support per-page, we flush on exec
 * fault if HWEXEC is not set
 */
static inline int pte_need_exec_flush(pte_t pte, int set_pte)
{
	return pte_looks_normal(pte) && is_exec_fault() &&
		!(pte_val(pte) & _PAGE_HWEXEC);
}