1 /* 2 * drivers/s390/char/sclp_quiesce.c 3 * signal quiesce handler 4 * 5 * (C) Copyright IBM Corp. 1999,2004 6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> 7 * Peter Oberparleiter <peter.oberparleiter@de.ibm.com> 8 */ 9 10 #include <linux/config.h> 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/cpumask.h> 14 #include <linux/smp.h> 15 #include <linux/init.h> 16 #include <linux/reboot.h> 17 #include <asm/atomic.h> 18 #include <asm/ptrace.h> 19 #include <asm/sigp.h> 20 21 #include "sclp.h" 22 23 24 #ifdef CONFIG_SMP 25 /* Signal completion of shutdown process. All CPUs except the first to enter 26 * this function: go to stopped state. First CPU: wait until all other 27 * CPUs are in stopped or check stop state. Afterwards, load special PSW 28 * to indicate completion. */ 29 static void 30 do_load_quiesce_psw(void * __unused) 31 { 32 static atomic_t cpuid = ATOMIC_INIT(-1); 33 psw_t quiesce_psw; 34 int cpu; 35 36 if (atomic_cmpxchg(&cpuid, -1, smp_processor_id()) != -1) 37 signal_processor(smp_processor_id(), sigp_stop); 38 /* Wait for all other cpus to enter stopped state */ 39 for_each_online_cpu(cpu) { 40 if (cpu == smp_processor_id()) 41 continue; 42 while(!smp_cpu_not_running(cpu)) 43 cpu_relax(); 44 } 45 /* Quiesce the last cpu with the special psw */ 46 quiesce_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT; 47 quiesce_psw.addr = 0xfff; 48 __load_psw(quiesce_psw); 49 } 50 51 /* Shutdown handler. Perform shutdown function on all CPUs. */ 52 static void 53 do_machine_quiesce(void) 54 { 55 on_each_cpu(do_load_quiesce_psw, NULL, 0, 0); 56 } 57 #else 58 /* Shutdown handler. Signal completion of shutdown by loading special PSW. */ 59 static void 60 do_machine_quiesce(void) 61 { 62 psw_t quiesce_psw; 63 64 quiesce_psw.mask = PSW_BASE_BITS | PSW_MASK_WAIT; 65 quiesce_psw.addr = 0xfff; 66 __load_psw(quiesce_psw); 67 } 68 #endif 69 70 /* Handler for quiesce event. Start shutdown procedure. */ 71 static void 72 sclp_quiesce_handler(struct evbuf_header *evbuf) 73 { 74 _machine_restart = (void *) do_machine_quiesce; 75 _machine_halt = do_machine_quiesce; 76 _machine_power_off = do_machine_quiesce; 77 ctrl_alt_del(); 78 } 79 80 static struct sclp_register sclp_quiesce_event = { 81 .receive_mask = EvTyp_SigQuiesce_Mask, 82 .receiver_fn = sclp_quiesce_handler 83 }; 84 85 /* Initialize quiesce driver. */ 86 static int __init 87 sclp_quiesce_init(void) 88 { 89 int rc; 90 91 rc = sclp_register(&sclp_quiesce_event); 92 if (rc) 93 printk(KERN_WARNING "sclp: could not register quiesce handler " 94 "(rc=%d)\n", rc); 95 return rc; 96 } 97 98 module_init(sclp_quiesce_init); 99