xnu-7195.101.1.tar.gz

[apple/xnu.git] / osfmk / arm / cpu_common.c

diff --git a/osfmk/arm/cpu_common.c b/osfmk/arm/cpu_common.c
index 11ad96d9e0f6948f04012a8fc54b82ed4c28cc2d..faa3b1e80be0e8e6d2146ed4f9cb4c3a18a1e907 100644 (file)
--- a/osfmk/arm/cpu_common.c
+++ b/osfmk/arm/cpu_common.c
@@ -62,13 +62,15 @@ vm_address_t     percpu_base_cur;
 cpu_data_t       PERCPU_DATA(cpu_data);
 cpu_data_entry_t CpuDataEntries[MAX_CPUS];
 
-static lck_grp_t cpu_lck_grp;
-static lck_rw_t cpu_state_lock;
+static LCK_GRP_DECLARE(cpu_lck_grp, "cpu_lck_grp");
+static LCK_RW_DECLARE(cpu_state_lock, &cpu_lck_grp);
 
 unsigned int    real_ncpus = 1;
 boolean_t       idle_enable = FALSE;
 uint64_t        wake_abstime = 0x0ULL;
 
+extern uint64_t xcall_ack_timeout_abstime;
+
 #if defined(HAS_IPI)
 extern unsigned int gFastIPI;
 #endif /* defined(HAS_IPI) */
@@ -427,6 +429,11 @@ cpu_signal_internal(cpu_data_t *target_proc,
        }
 
        if ((signal == SIGPxcall) || (signal == SIGPxcallImm)) {
+               uint64_t start_mabs_time, max_mabs_time, current_mabs_time;
+               current_mabs_time = start_mabs_time = mach_absolute_time();
+               max_mabs_time = xcall_ack_timeout_abstime + current_mabs_time;
+               assert(max_mabs_time > current_mabs_time);
+
                do {
                        current_signals = target_proc->cpu_signal;
                        if ((current_signals & SIGPdisabled) == SIGPdisabled) {
@@ -447,7 +454,20 @@ cpu_signal_internal(cpu_data_t *target_proc,
                        if (!swap_success && (current_proc->cpu_signal & signal)) {
                                cpu_handle_xcall(current_proc);
                        }
-               } while (!swap_success);
+               } while (!swap_success && ((current_mabs_time = mach_absolute_time()) < max_mabs_time));
+
+               /*
+                * If we time out while waiting for the target CPU to respond, it's possible that no
+                * other CPU is available to handle the watchdog interrupt that would eventually trigger
+                * a panic. To prevent this from happening, we just panic here to flag this condition.
+                */
+               if (__improbable(current_mabs_time >= max_mabs_time)) {
+                       uint64_t end_time_ns, xcall_ack_timeout_ns;
+                       absolutetime_to_nanoseconds(current_mabs_time - start_mabs_time, &end_time_ns);
+                       absolutetime_to_nanoseconds(xcall_ack_timeout_abstime, &xcall_ack_timeout_ns);
+                       panic("CPU%u has failed to respond to cross-call after %llu nanoseconds (timeout = %llu ns)",
+                           target_proc->cpu_number, end_time_ns, xcall_ack_timeout_ns);
+               }
 
                if (signal == SIGPxcallImm) {
                        target_proc->cpu_imm_xcall_p0 = p0;
@@ -825,13 +845,6 @@ ml_cpu_can_exit(__unused int cpu_id)
        return false;
 }
 
-void
-ml_cpu_init_state(void)
-{
-       lck_grp_init(&cpu_lck_grp, "cpu_lck_grp", LCK_GRP_ATTR_NULL);
-       lck_rw_init(&cpu_state_lock, &cpu_lck_grp, LCK_ATTR_NULL);
-}
-
 #ifdef USE_APPLEARMSMP
 
 void