- return buftail.fp-1;
-}
-
-/* Compare two addresses and see if they're on the same page */
-#define CMP_ADDR_EQUAL(x,y,offset) ((((unsigned long) x) >> PAGE_SHIFT) \
- == ((((unsigned long) y) + offset) >> PAGE_SHIFT))
-
-/* check that the page(s) containing the frame tail are present */
-static int pages_present(struct frame_tail *tail)
-{
- struct mm_struct * mm = current->mm;
-
- if (!check_user_page_readable(mm, (unsigned long)tail))
- return 0;
-
- if (CMP_ADDR_EQUAL(tail, tail, 8))
- return 1;
-
- if (!check_user_page_readable(mm, ((unsigned long)tail) + 8))
- return 0;
-
- return 1;
-}
-
-/*
- * | | /\ Higher addresses
- * | |
- * --------------- stack base (address of current_thread_info)
- * | thread info |
- * . .
- * | stack |
- * --------------- saved regs->ARM_fp value if valid (frame_tail address)
- * . .
- * --------------- struct pt_regs stored on stack (struct pt_regs *)
- * | |
- * . .
- * | |
- * --------------- %esp
- * | |
- * | | \/ Lower addresses
- *
- * Thus, &pt_regs <-> stack base restricts the valid(ish) fp values
- */
-static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs)
-{
- unsigned long tailaddr = (unsigned long)tail;
- unsigned long stack = (unsigned long)regs;
- unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;
-
- return (tailaddr > stack) && (tailaddr < stack_base);