1 /* 2 * arch/ia64/kernel/crash.c 3 * 4 * Architecture specific (ia64) functions for kexec based crash dumps. 5 * 6 * Created by: Khalid Aziz <khalid.aziz@hp.com> 7 * Copyright (C) 2005 Hewlett-Packard Development Company, L.P. 8 * Copyright (C) 2005 Intel Corp Zou Nan hai <nanhai.zou@intel.com> 9 * 10 */ 11 #include <linux/smp.h> 12 #include <linux/delay.h> 13 #include <linux/crash_dump.h> 14 #include <linux/bootmem.h> 15 #include <linux/kexec.h> 16 #include <linux/elfcore.h> 17 #include <linux/sysctl.h> 18 #include <linux/init.h> 19 #include <linux/kdebug.h> 20 21 #include <asm/mca.h> 22 23 int kdump_status[NR_CPUS]; 24 static atomic_t kdump_cpu_frozen; 25 atomic_t kdump_in_progress; 26 static int kdump_freeze_monarch; 27 static int kdump_on_init = 1; 28 static int kdump_on_fatal_mca = 1; 29 30 extern void ia64_dump_cpu_regs(void *); 31 32 static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus); 33 34 void 35 crash_save_this_cpu(void) 36 { 37 void *buf; 38 unsigned long cfm, sof, sol; 39 40 int cpu = smp_processor_id(); 41 struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu); 42 43 elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg); 44 memset(prstatus, 0, sizeof(*prstatus)); 45 prstatus->pr_pid = current->pid; 46 47 ia64_dump_cpu_regs(dst); 48 cfm = dst[43]; 49 sol = (cfm >> 7) & 0x7f; 50 sof = cfm & 0x7f; 51 dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46], 52 sof - sol); 53 54 buf = (u64 *) per_cpu_ptr(crash_notes, cpu); 55 if (!buf) 56 return; 57 buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus, 58 sizeof(*prstatus)); 59 final_note(buf); 60 } 61 62 #ifdef CONFIG_SMP 63 static int 64 kdump_wait_cpu_freeze(void) 65 { 66 int cpu_num = num_online_cpus() - 1; 67 int timeout = 1000; 68 while(timeout-- > 0) { 69 if (atomic_read(&kdump_cpu_frozen) == cpu_num) 70 return 0; 71 udelay(1000); 72 } 73 return 1; 74 } 75 #endif 76 77 void 78 machine_crash_shutdown(struct pt_regs *pt) 79 { 80 /* This function is only called after the system 81 * has paniced or is otherwise in a critical state. 82 * The minimum amount of code to allow a kexec'd kernel 83 * to run successfully needs to happen here. 84 * 85 * In practice this means shooting down the other cpus in 86 * an SMP system. 87 */ 88 kexec_disable_iosapic(); 89 #ifdef CONFIG_SMP 90 /* 91 * If kdump_on_init is set and an INIT is asserted here, kdump will 92 * be started again via INIT monarch. 93 */ 94 local_irq_disable(); 95 ia64_set_psr_mc(); /* mask MCA/INIT */ 96 if (atomic_inc_return(&kdump_in_progress) != 1) 97 unw_init_running(kdump_cpu_freeze, NULL); 98 99 /* 100 * Now this cpu is ready for kdump. 101 * Stop all others by IPI or INIT. They could receive INIT from 102 * outside and might be INIT monarch, but only thing they have to 103 * do is falling into kdump_cpu_freeze(). 104 * 105 * If an INIT is asserted here: 106 * - All receivers might be slaves, since some of cpus could already 107 * be frozen and INIT might be masked on monarch. In this case, 108 * all slaves will be frozen soon since kdump_in_progress will let 109 * them into DIE_INIT_SLAVE_LEAVE. 110 * - One might be a monarch, but INIT rendezvous will fail since 111 * at least this cpu already have INIT masked so it never join 112 * to the rendezvous. In this case, all slaves and monarch will 113 * be frozen soon with no wait since the INIT rendezvous is skipped 114 * by kdump_in_progress. 115 */ 116 kdump_smp_send_stop(); 117 /* not all cpu response to IPI, send INIT to freeze them */ 118 if (kdump_wait_cpu_freeze()) { 119 kdump_smp_send_init(); 120 /* wait again, don't go ahead if possible */ 121 kdump_wait_cpu_freeze(); 122 } 123 #endif 124 } 125 126 static void 127 machine_kdump_on_init(void) 128 { 129 crash_save_vmcoreinfo(); 130 local_irq_disable(); 131 kexec_disable_iosapic(); 132 machine_kexec(ia64_kimage); 133 } 134 135 void 136 kdump_cpu_freeze(struct unw_frame_info *info, void *arg) 137 { 138 int cpuid; 139 140 local_irq_disable(); 141 cpuid = smp_processor_id(); 142 crash_save_this_cpu(); 143 current->thread.ksp = (__u64)info->sw - 16; 144 145 ia64_set_psr_mc(); /* mask MCA/INIT and stop reentrance */ 146 147 atomic_inc(&kdump_cpu_frozen); 148 kdump_status[cpuid] = 1; 149 mb(); 150 for (;;) 151 cpu_relax(); 152 } 153 154 static int 155 kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data) 156 { 157 struct ia64_mca_notify_die *nd; 158 struct die_args *args = data; 159 160 if (atomic_read(&kdump_in_progress)) { 161 switch (val) { 162 case DIE_INIT_MONARCH_LEAVE: 163 if (!kdump_freeze_monarch) 164 break; 165 /* fall through */ 166 case DIE_INIT_SLAVE_LEAVE: 167 case DIE_INIT_MONARCH_ENTER: 168 case DIE_MCA_RENDZVOUS_LEAVE: 169 unw_init_running(kdump_cpu_freeze, NULL); 170 break; 171 } 172 } 173 174 if (!kdump_on_init && !kdump_on_fatal_mca) 175 return NOTIFY_DONE; 176 177 if (!ia64_kimage) { 178 if (val == DIE_INIT_MONARCH_LEAVE) 179 ia64_mca_printk(KERN_NOTICE 180 "%s: kdump not configured\n", 181 __func__); 182 return NOTIFY_DONE; 183 } 184 185 if (val != DIE_INIT_MONARCH_LEAVE && 186 val != DIE_INIT_MONARCH_PROCESS && 187 val != DIE_MCA_MONARCH_LEAVE) 188 return NOTIFY_DONE; 189 190 nd = (struct ia64_mca_notify_die *)args->err; 191 192 switch (val) { 193 case DIE_INIT_MONARCH_PROCESS: 194 /* Reason code 1 means machine check rendezvous*/ 195 if (kdump_on_init && (nd->sos->rv_rc != 1)) { 196 if (atomic_inc_return(&kdump_in_progress) != 1) 197 kdump_freeze_monarch = 1; 198 } 199 break; 200 case DIE_INIT_MONARCH_LEAVE: 201 /* Reason code 1 means machine check rendezvous*/ 202 if (kdump_on_init && (nd->sos->rv_rc != 1)) 203 machine_kdump_on_init(); 204 break; 205 case DIE_MCA_MONARCH_LEAVE: 206 /* *(nd->data) indicate if MCA is recoverable */ 207 if (kdump_on_fatal_mca && !(*(nd->data))) { 208 if (atomic_inc_return(&kdump_in_progress) == 1) 209 machine_kdump_on_init(); 210 /* We got fatal MCA while kdump!? No way!! */ 211 } 212 break; 213 } 214 return NOTIFY_DONE; 215 } 216 217 #ifdef CONFIG_SYSCTL 218 static struct ctl_table kdump_ctl_table[] = { 219 { 220 .procname = "kdump_on_init", 221 .data = &kdump_on_init, 222 .maxlen = sizeof(int), 223 .mode = 0644, 224 .proc_handler = proc_dointvec, 225 }, 226 { 227 .procname = "kdump_on_fatal_mca", 228 .data = &kdump_on_fatal_mca, 229 .maxlen = sizeof(int), 230 .mode = 0644, 231 .proc_handler = proc_dointvec, 232 }, 233 { } 234 }; 235 236 static struct ctl_table sys_table[] = { 237 { 238 .procname = "kernel", 239 .mode = 0555, 240 .child = kdump_ctl_table, 241 }, 242 { } 243 }; 244 #endif 245 246 static int 247 machine_crash_setup(void) 248 { 249 /* be notified before default_monarch_init_process */ 250 static struct notifier_block kdump_init_notifier_nb = { 251 .notifier_call = kdump_init_notifier, 252 .priority = 1, 253 }; 254 int ret; 255 if((ret = register_die_notifier(&kdump_init_notifier_nb)) != 0) 256 return ret; 257 #ifdef CONFIG_SYSCTL 258 register_sysctl_table(sys_table); 259 #endif 260 return 0; 261 } 262 263 __initcall(machine_crash_setup); 264 265