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