1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * arch/ia64/kernel/crash.c 4 * 5 * Architecture specific (ia64) functions for kexec based crash dumps. 6 * 7 * Created by: Khalid Aziz <khalid.aziz@hp.com> 8 * Copyright (C) 2005 Hewlett-Packard Development Company, L.P. 9 * Copyright (C) 2005 Intel Corp Zou Nan hai <nanhai.zou@intel.com> 10 * 11 */ 12 #include <linux/smp.h> 13 #include <linux/delay.h> 14 #include <linux/crash_dump.h> 15 #include <linux/memblock.h> 16 #include <linux/kexec.h> 17 #include <linux/elfcore.h> 18 #include <linux/sysctl.h> 19 #include <linux/init.h> 20 #include <linux/kdebug.h> 21 22 #include <asm/mca.h> 23 24 int kdump_status[NR_CPUS]; 25 static atomic_t kdump_cpu_frozen; 26 atomic_t kdump_in_progress; 27 static int kdump_freeze_monarch; 28 static int kdump_on_init = 1; 29 static int kdump_on_fatal_mca = 1; 30 31 extern void ia64_dump_cpu_regs(void *); 32 33 static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus); 34 35 void 36 crash_save_this_cpu(void) 37 { 38 void *buf; 39 unsigned long cfm, sof, sol; 40 41 int cpu = smp_processor_id(); 42 struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu); 43 44 elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg); 45 memset(prstatus, 0, sizeof(*prstatus)); 46 prstatus->pr_pid = current->pid; 47 48 ia64_dump_cpu_regs(dst); 49 cfm = dst[43]; 50 sol = (cfm >> 7) & 0x7f; 51 sof = cfm & 0x7f; 52 dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46], 53 sof - sol); 54 55 buf = (u64 *) per_cpu_ptr(crash_notes, cpu); 56 if (!buf) 57 return; 58 buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus, 59 sizeof(*prstatus)); 60 final_note(buf); 61 } 62 63 #ifdef CONFIG_SMP 64 static int 65 kdump_wait_cpu_freeze(void) 66 { 67 int cpu_num = num_online_cpus() - 1; 68 int timeout = 1000; 69 while(timeout-- > 0) { 70 if (atomic_read(&kdump_cpu_frozen) == cpu_num) 71 return 0; 72 udelay(1000); 73 } 74 return 1; 75 } 76 #endif 77 78 void 79 machine_crash_shutdown(struct pt_regs *pt) 80 { 81 /* This function is only called after the system 82 * has paniced or is otherwise in a critical state. 83 * The minimum amount of code to allow a kexec'd kernel 84 * to run successfully needs to happen here. 85 * 86 * In practice this means shooting down the other cpus in 87 * an SMP system. 88 */ 89 kexec_disable_iosapic(); 90 #ifdef CONFIG_SMP 91 /* 92 * If kdump_on_init is set and an INIT is asserted here, kdump will 93 * be started again via INIT monarch. 94 */ 95 local_irq_disable(); 96 ia64_set_psr_mc(); /* mask MCA/INIT */ 97 if (atomic_inc_return(&kdump_in_progress) != 1) 98 unw_init_running(kdump_cpu_freeze, NULL); 99 100 /* 101 * Now this cpu is ready for kdump. 102 * Stop all others by IPI or INIT. They could receive INIT from 103 * outside and might be INIT monarch, but only thing they have to 104 * do is falling into kdump_cpu_freeze(). 105 * 106 * If an INIT is asserted here: 107 * - All receivers might be slaves, since some of cpus could already 108 * be frozen and INIT might be masked on monarch. In this case, 109 * all slaves will be frozen soon since kdump_in_progress will let 110 * them into DIE_INIT_SLAVE_LEAVE. 111 * - One might be a monarch, but INIT rendezvous will fail since 112 * at least this cpu already have INIT masked so it never join 113 * to the rendezvous. In this case, all slaves and monarch will 114 * be frozen soon with no wait since the INIT rendezvous is skipped 115 * by kdump_in_progress. 116 */ 117 kdump_smp_send_stop(); 118 /* not all cpu response to IPI, send INIT to freeze them */ 119 if (kdump_wait_cpu_freeze()) { 120 kdump_smp_send_init(); 121 /* wait again, don't go ahead if possible */ 122 kdump_wait_cpu_freeze(); 123 } 124 #endif 125 } 126 127 static void 128 machine_kdump_on_init(void) 129 { 130 crash_save_vmcoreinfo(); 131 local_irq_disable(); 132 kexec_disable_iosapic(); 133 machine_kexec(ia64_kimage); 134 } 135 136 void 137 kdump_cpu_freeze(struct unw_frame_info *info, void *arg) 138 { 139 int cpuid; 140 141 local_irq_disable(); 142 cpuid = smp_processor_id(); 143 crash_save_this_cpu(); 144 current->thread.ksp = (__u64)info->sw - 16; 145 146 ia64_set_psr_mc(); /* mask MCA/INIT and stop reentrance */ 147 148 atomic_inc(&kdump_cpu_frozen); 149 kdump_status[cpuid] = 1; 150 mb(); 151 for (;;) 152 cpu_relax(); 153 } 154 155 static int 156 kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data) 157 { 158 struct ia64_mca_notify_die *nd; 159 struct die_args *args = data; 160 161 if (atomic_read(&kdump_in_progress)) { 162 switch (val) { 163 case DIE_INIT_MONARCH_LEAVE: 164 if (!kdump_freeze_monarch) 165 break; 166 /* fall through */ 167 case DIE_INIT_SLAVE_LEAVE: 168 case DIE_INIT_MONARCH_ENTER: 169 case DIE_MCA_RENDZVOUS_LEAVE: 170 unw_init_running(kdump_cpu_freeze, NULL); 171 break; 172 } 173 } 174 175 if (!kdump_on_init && !kdump_on_fatal_mca) 176 return NOTIFY_DONE; 177 178 if (!ia64_kimage) { 179 if (val == DIE_INIT_MONARCH_LEAVE) 180 ia64_mca_printk(KERN_NOTICE 181 "%s: kdump not configured\n", 182 __func__); 183 return NOTIFY_DONE; 184 } 185 186 if (val != DIE_INIT_MONARCH_LEAVE && 187 val != DIE_INIT_MONARCH_PROCESS && 188 val != DIE_MCA_MONARCH_LEAVE) 189 return NOTIFY_DONE; 190 191 nd = (struct ia64_mca_notify_die *)args->err; 192 193 switch (val) { 194 case DIE_INIT_MONARCH_PROCESS: 195 /* Reason code 1 means machine check rendezvous*/ 196 if (kdump_on_init && (nd->sos->rv_rc != 1)) { 197 if (atomic_inc_return(&kdump_in_progress) != 1) 198 kdump_freeze_monarch = 1; 199 } 200 break; 201 case DIE_INIT_MONARCH_LEAVE: 202 /* Reason code 1 means machine check rendezvous*/ 203 if (kdump_on_init && (nd->sos->rv_rc != 1)) 204 machine_kdump_on_init(); 205 break; 206 case DIE_MCA_MONARCH_LEAVE: 207 /* *(nd->data) indicate if MCA is recoverable */ 208 if (kdump_on_fatal_mca && !(*(nd->data))) { 209 if (atomic_inc_return(&kdump_in_progress) == 1) 210 machine_kdump_on_init(); 211 /* We got fatal MCA while kdump!? No way!! */ 212 } 213 break; 214 } 215 return NOTIFY_DONE; 216 } 217 218 #ifdef CONFIG_SYSCTL 219 static struct ctl_table kdump_ctl_table[] = { 220 { 221 .procname = "kdump_on_init", 222 .data = &kdump_on_init, 223 .maxlen = sizeof(int), 224 .mode = 0644, 225 .proc_handler = proc_dointvec, 226 }, 227 { 228 .procname = "kdump_on_fatal_mca", 229 .data = &kdump_on_fatal_mca, 230 .maxlen = sizeof(int), 231 .mode = 0644, 232 .proc_handler = proc_dointvec, 233 }, 234 { } 235 }; 236 237 static struct ctl_table sys_table[] = { 238 { 239 .procname = "kernel", 240 .mode = 0555, 241 .child = kdump_ctl_table, 242 }, 243 { } 244 }; 245 #endif 246 247 static int 248 machine_crash_setup(void) 249 { 250 /* be notified before default_monarch_init_process */ 251 static struct notifier_block kdump_init_notifier_nb = { 252 .notifier_call = kdump_init_notifier, 253 .priority = 1, 254 }; 255 int ret; 256 if((ret = register_die_notifier(&kdump_init_notifier_nb)) != 0) 257 return ret; 258 #ifdef CONFIG_SYSCTL 259 register_sysctl_table(sys_table); 260 #endif 261 return 0; 262 } 263 264 __initcall(machine_crash_setup); 265 266