1 /* 2 * Machine check handler 3 * 4 * Copyright IBM Corp. 2000, 2009 5 * Author(s): Ingo Adlung <adlung@de.ibm.com>, 6 * Martin Schwidefsky <schwidefsky@de.ibm.com>, 7 * Cornelia Huck <cornelia.huck@de.ibm.com>, 8 * Heiko Carstens <heiko.carstens@de.ibm.com>, 9 */ 10 11 #include <linux/kernel_stat.h> 12 #include <linux/init.h> 13 #include <linux/errno.h> 14 #include <linux/hardirq.h> 15 #include <linux/time.h> 16 #include <linux/module.h> 17 #include <asm/lowcore.h> 18 #include <asm/smp.h> 19 #include <asm/etr.h> 20 #include <asm/cputime.h> 21 #include <asm/nmi.h> 22 #include <asm/crw.h> 23 #include <asm/switch_to.h> 24 #include <asm/fpu-internal.h> 25 #include <asm/ctl_reg.h> 26 27 struct mcck_struct { 28 int kill_task; 29 int channel_report; 30 int warning; 31 unsigned long long mcck_code; 32 }; 33 34 static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck); 35 36 static void s390_handle_damage(char *msg) 37 { 38 smp_send_stop(); 39 disabled_wait((unsigned long) __builtin_return_address(0)); 40 while (1); 41 } 42 43 /* 44 * Main machine check handler function. Will be called with interrupts enabled 45 * or disabled and machine checks enabled or disabled. 46 */ 47 void s390_handle_mcck(void) 48 { 49 unsigned long flags; 50 struct mcck_struct mcck; 51 52 /* 53 * Disable machine checks and get the current state of accumulated 54 * machine checks. Afterwards delete the old state and enable machine 55 * checks again. 56 */ 57 local_irq_save(flags); 58 local_mcck_disable(); 59 mcck = *this_cpu_ptr(&cpu_mcck); 60 memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck)); 61 clear_cpu_flag(CIF_MCCK_PENDING); 62 local_mcck_enable(); 63 local_irq_restore(flags); 64 65 if (mcck.channel_report) 66 crw_handle_channel_report(); 67 /* 68 * A warning may remain for a prolonged period on the bare iron. 69 * (actually until the machine is powered off, or the problem is gone) 70 * So we just stop listening for the WARNING MCH and avoid continuously 71 * being interrupted. One caveat is however, that we must do this per 72 * processor and cannot use the smp version of ctl_clear_bit(). 73 * On VM we only get one interrupt per virtally presented machinecheck. 74 * Though one suffices, we may get one interrupt per (virtual) cpu. 75 */ 76 if (mcck.warning) { /* WARNING pending ? */ 77 static int mchchk_wng_posted = 0; 78 79 /* Use single cpu clear, as we cannot handle smp here. */ 80 __ctl_clear_bit(14, 24); /* Disable WARNING MCH */ 81 if (xchg(&mchchk_wng_posted, 1) == 0) 82 kill_cad_pid(SIGPWR, 1); 83 } 84 if (mcck.kill_task) { 85 local_irq_enable(); 86 printk(KERN_EMERG "mcck: Terminating task because of machine " 87 "malfunction (code 0x%016llx).\n", mcck.mcck_code); 88 printk(KERN_EMERG "mcck: task: %s, pid: %d.\n", 89 current->comm, current->pid); 90 do_exit(SIGSEGV); 91 } 92 } 93 EXPORT_SYMBOL_GPL(s390_handle_mcck); 94 95 /* 96 * returns 0 if all registers could be validated 97 * returns 1 otherwise 98 */ 99 static int notrace s390_revalidate_registers(struct mci *mci) 100 { 101 int kill_task; 102 u64 zero; 103 void *fpt_save_area, *fpt_creg_save_area; 104 105 kill_task = 0; 106 zero = 0; 107 108 if (!mci->gr) { 109 /* 110 * General purpose registers couldn't be restored and have 111 * unknown contents. Process needs to be terminated. 112 */ 113 kill_task = 1; 114 } 115 if (!mci->fp) { 116 /* 117 * Floating point registers can't be restored and 118 * therefore the process needs to be terminated. 119 */ 120 kill_task = 1; 121 } 122 fpt_save_area = &S390_lowcore.floating_pt_save_area; 123 fpt_creg_save_area = &S390_lowcore.fpt_creg_save_area; 124 if (!mci->fc) { 125 /* 126 * Floating point control register can't be restored. 127 * Task will be terminated. 128 */ 129 asm volatile("lfpc 0(%0)" : : "a" (&zero), "m" (zero)); 130 kill_task = 1; 131 } else 132 asm volatile("lfpc 0(%0)" : : "a" (fpt_creg_save_area)); 133 134 if (!MACHINE_HAS_VX) { 135 /* Revalidate floating point registers */ 136 asm volatile( 137 " ld 0,0(%0)\n" 138 " ld 1,8(%0)\n" 139 " ld 2,16(%0)\n" 140 " ld 3,24(%0)\n" 141 " ld 4,32(%0)\n" 142 " ld 5,40(%0)\n" 143 " ld 6,48(%0)\n" 144 " ld 7,56(%0)\n" 145 " ld 8,64(%0)\n" 146 " ld 9,72(%0)\n" 147 " ld 10,80(%0)\n" 148 " ld 11,88(%0)\n" 149 " ld 12,96(%0)\n" 150 " ld 13,104(%0)\n" 151 " ld 14,112(%0)\n" 152 " ld 15,120(%0)\n" 153 : : "a" (fpt_save_area)); 154 } else { 155 /* Revalidate vector registers */ 156 union ctlreg0 cr0; 157 158 if (!mci->vr) { 159 /* 160 * Vector registers can't be restored and therefore 161 * the process needs to be terminated. 162 */ 163 kill_task = 1; 164 } 165 cr0.val = S390_lowcore.cregs_save_area[0]; 166 cr0.afp = cr0.vx = 1; 167 __ctl_load(cr0.val, 0, 0); 168 restore_vx_regs((__vector128 *) 169 &S390_lowcore.vector_save_area); 170 __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0); 171 } 172 /* Revalidate access registers */ 173 asm volatile( 174 " lam 0,15,0(%0)" 175 : : "a" (&S390_lowcore.access_regs_save_area)); 176 if (!mci->ar) { 177 /* 178 * Access registers have unknown contents. 179 * Terminating task. 180 */ 181 kill_task = 1; 182 } 183 /* Revalidate control registers */ 184 if (!mci->cr) { 185 /* 186 * Control registers have unknown contents. 187 * Can't recover and therefore stopping machine. 188 */ 189 s390_handle_damage("invalid control registers."); 190 } else { 191 asm volatile( 192 " lctlg 0,15,0(%0)" 193 : : "a" (&S390_lowcore.cregs_save_area)); 194 } 195 /* 196 * We don't even try to revalidate the TOD register, since we simply 197 * can't write something sensible into that register. 198 */ 199 /* 200 * See if we can revalidate the TOD programmable register with its 201 * old contents (should be zero) otherwise set it to zero. 202 */ 203 if (!mci->pr) 204 asm volatile( 205 " sr 0,0\n" 206 " sckpf" 207 : : : "0", "cc"); 208 else 209 asm volatile( 210 " l 0,0(%0)\n" 211 " sckpf" 212 : : "a" (&S390_lowcore.tod_progreg_save_area) 213 : "0", "cc"); 214 /* Revalidate clock comparator register */ 215 set_clock_comparator(S390_lowcore.clock_comparator); 216 /* Check if old PSW is valid */ 217 if (!mci->wp) 218 /* 219 * Can't tell if we come from user or kernel mode 220 * -> stopping machine. 221 */ 222 s390_handle_damage("old psw invalid."); 223 224 if (!mci->ms || !mci->pm || !mci->ia) 225 kill_task = 1; 226 227 return kill_task; 228 } 229 230 #define MAX_IPD_COUNT 29 231 #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */ 232 233 #define ED_STP_ISLAND 6 /* External damage STP island check */ 234 #define ED_STP_SYNC 7 /* External damage STP sync check */ 235 #define ED_ETR_SYNC 12 /* External damage ETR sync check */ 236 #define ED_ETR_SWITCH 13 /* External damage ETR switch to local */ 237 238 /* 239 * machine check handler. 240 */ 241 void notrace s390_do_machine_check(struct pt_regs *regs) 242 { 243 static int ipd_count; 244 static DEFINE_SPINLOCK(ipd_lock); 245 static unsigned long long last_ipd; 246 struct mcck_struct *mcck; 247 unsigned long long tmp; 248 struct mci *mci; 249 int umode; 250 251 nmi_enter(); 252 inc_irq_stat(NMI_NMI); 253 mci = (struct mci *) &S390_lowcore.mcck_interruption_code; 254 mcck = this_cpu_ptr(&cpu_mcck); 255 umode = user_mode(regs); 256 257 if (mci->sd) { 258 /* System damage -> stopping machine */ 259 s390_handle_damage("received system damage machine check."); 260 } 261 if (mci->pd) { 262 if (mci->b) { 263 /* Processing backup -> verify if we can survive this */ 264 u64 z_mcic, o_mcic, t_mcic; 265 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29); 266 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 | 267 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 | 268 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 | 269 1ULL<<16); 270 t_mcic = *(u64 *)mci; 271 272 if (((t_mcic & z_mcic) != 0) || 273 ((t_mcic & o_mcic) != o_mcic)) { 274 s390_handle_damage("processing backup machine " 275 "check with damage."); 276 } 277 278 /* 279 * Nullifying exigent condition, therefore we might 280 * retry this instruction. 281 */ 282 spin_lock(&ipd_lock); 283 tmp = get_tod_clock(); 284 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME) 285 ipd_count++; 286 else 287 ipd_count = 1; 288 last_ipd = tmp; 289 if (ipd_count == MAX_IPD_COUNT) 290 s390_handle_damage("too many ipd retries."); 291 spin_unlock(&ipd_lock); 292 } else { 293 /* Processing damage -> stopping machine */ 294 s390_handle_damage("received instruction processing " 295 "damage machine check."); 296 } 297 } 298 if (s390_revalidate_registers(mci)) { 299 if (umode) { 300 /* 301 * Couldn't restore all register contents while in 302 * user mode -> mark task for termination. 303 */ 304 mcck->kill_task = 1; 305 mcck->mcck_code = *(unsigned long long *) mci; 306 set_cpu_flag(CIF_MCCK_PENDING); 307 } else { 308 /* 309 * Couldn't restore all register contents while in 310 * kernel mode -> stopping machine. 311 */ 312 s390_handle_damage("unable to revalidate registers."); 313 } 314 } 315 if (mci->cd) { 316 /* Timing facility damage */ 317 s390_handle_damage("TOD clock damaged"); 318 } 319 if (mci->ed && mci->ec) { 320 /* External damage */ 321 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC)) 322 etr_sync_check(); 323 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH)) 324 etr_switch_to_local(); 325 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC)) 326 stp_sync_check(); 327 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND)) 328 stp_island_check(); 329 } 330 if (mci->se) 331 /* Storage error uncorrected */ 332 s390_handle_damage("received storage error uncorrected " 333 "machine check."); 334 if (mci->ke) 335 /* Storage key-error uncorrected */ 336 s390_handle_damage("received storage key-error uncorrected " 337 "machine check."); 338 if (mci->ds && mci->fa) 339 /* Storage degradation */ 340 s390_handle_damage("received storage degradation machine " 341 "check."); 342 if (mci->cp) { 343 /* Channel report word pending */ 344 mcck->channel_report = 1; 345 set_cpu_flag(CIF_MCCK_PENDING); 346 } 347 if (mci->w) { 348 /* Warning pending */ 349 mcck->warning = 1; 350 set_cpu_flag(CIF_MCCK_PENDING); 351 } 352 nmi_exit(); 353 } 354 355 static int __init machine_check_init(void) 356 { 357 ctl_set_bit(14, 25); /* enable external damage MCH */ 358 ctl_set_bit(14, 27); /* enable system recovery MCH */ 359 ctl_set_bit(14, 24); /* enable warning MCH */ 360 return 0; 361 } 362 arch_initcall(machine_check_init); 363