+static void
+pfm_alt_save_pmu_state(void *data)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(current);
+
+ DPRINT(("called\n"));
+
+ /*
+ * should not be necessary but
+ * let's take not risk
+ */
+ pfm_clear_psr_up();
+ pfm_clear_psr_pp();
+ ia64_psr(regs)->pp = 0;
+
+ /*
+ * This call is required
+ * May cause a spurious interrupt on some processors
+ */
+ pfm_freeze_pmu();
+
+ ia64_srlz_d();
+}
+
+void
+pfm_alt_restore_pmu_state(void *data)
+{
+ struct pt_regs *regs;
+
+ regs = task_pt_regs(current);
+
+ DPRINT(("called\n"));
+
+ /*
+ * put PMU back in state expected
+ * by perfmon
+ */
+ pfm_clear_psr_up();
+ pfm_clear_psr_pp();
+ ia64_psr(regs)->pp = 0;
+
+ /*
+ * perfmon runs with PMU unfrozen at all times
+ */
+ pfm_unfreeze_pmu();
+
+ ia64_srlz_d();
+}
+
+int
+pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
+{
+ int ret, i;
+ int reserve_cpu;
+
+ /* some sanity checks */
+ if (hdl == NULL || hdl->handler == NULL) return -EINVAL;
+
+ /* do the easy test first */
+ if (pfm_alt_intr_handler) return -EBUSY;
+
+ /* one at a time in the install or remove, just fail the others */
+ if (!spin_trylock(&pfm_alt_install_check)) {
+ return -EBUSY;
+ }
+
+ /* reserve our session */
+ for_each_online_cpu(reserve_cpu) {
+ ret = pfm_reserve_session(NULL, 1, reserve_cpu);
+ if (ret) goto cleanup_reserve;
+ }
+
+ /* save the current system wide pmu states */
+ ret = on_each_cpu(pfm_alt_save_pmu_state, NULL, 0, 1);
+ if (ret) {
+ DPRINT(("on_each_cpu() failed: %d\n", ret));
+ goto cleanup_reserve;
+ }
+
+ /* officially change to the alternate interrupt handler */
+ pfm_alt_intr_handler = hdl;
+
+ spin_unlock(&pfm_alt_install_check);
+
+ return 0;
+
+cleanup_reserve:
+ for_each_online_cpu(i) {
+ /* don't unreserve more than we reserved */
+ if (i >= reserve_cpu) break;
+
+ pfm_unreserve_session(NULL, 1, i);
+ }
+
+ spin_unlock(&pfm_alt_install_check);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(pfm_install_alt_pmu_interrupt);
+
+int
+pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
+{
+ int i;
+ int ret;
+
+ if (hdl == NULL) return -EINVAL;
+
+ /* cannot remove someone else's handler! */
+ if (pfm_alt_intr_handler != hdl) return -EINVAL;
+
+ /* one at a time in the install or remove, just fail the others */
+ if (!spin_trylock(&pfm_alt_install_check)) {
+ return -EBUSY;
+ }
+
+ pfm_alt_intr_handler = NULL;
+
+ ret = on_each_cpu(pfm_alt_restore_pmu_state, NULL, 0, 1);
+ if (ret) {
+ DPRINT(("on_each_cpu() failed: %d\n", ret));
+ }
+
+ for_each_online_cpu(i) {
+ pfm_unreserve_session(NULL, 1, i);
+ }
+
+ spin_unlock(&pfm_alt_install_check);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pfm_remove_alt_pmu_interrupt);
+