- /* Allow both L1 and L2 at the onset */
- flags |= (STATUS_E1_MASK | STATUS_E2_MASK);
-
- /* Called from hard ISR (between irq_enter and irq_exit) */
- if (in_irq()) {
-
- /* If in L2 ISR, don't re-enable any further IRQs as this can
- * cause IRQ priorities to get upside down. e.g. it could allow
- * L1 be taken while in L2 hard ISR which is wrong not only in
- * theory, it can also cause the dreaded L1-L2-L1 scenario
- */
- if (flags & STATUS_A2_MASK)
- flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK);
-
- /* Even if in L1 ISR, allowe Higher prio L2 IRQs */
- else if (flags & STATUS_A1_MASK)
- flags &= ~(STATUS_E1_MASK);
- }
-
- /* called from soft IRQ, ideally we want to re-enable all levels */
-
- else if (in_softirq()) {
-
- /* However if this is case of L1 interrupted by L2,
- * re-enabling both may cause whaco L1-L2-L1 scenario
- * because ARC700 allows level 1 to interrupt an active L2 ISR
- * Thus we disable both
- * However some code, executing in soft ISR wants some IRQs
- * to be enabled so we re-enable L2 only
- *
- * How do we determine L1 intr by L2
- * -A2 is set (means in L2 ISR)
- * -E1 is set in this ISR's pt_regs->status32 which is
- * saved copy of status32_l2 when l2 ISR happened
- */
- struct pt_regs *pt = get_irq_regs();
-
- if ((flags & STATUS_A2_MASK) && pt &&
- (pt->status32 & STATUS_A1_MASK)) {
- /*flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); */
- flags &= ~(STATUS_E1_MASK);
- }
- }