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 asm volatile( 169 " la 1,%0\n" 170 " .word 0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */ 171 " .word 0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */ 172 : : "Q" (*(struct vx_array *) 173 &S390_lowcore.vector_save_area) : "1"); 174 __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0); 175 } 176 /* Revalidate access registers */ 177 asm volatile( 178 " lam 0,15,0(%0)" 179 : : "a" (&S390_lowcore.access_regs_save_area)); 180 if (!mci->ar) { 181 /* 182 * Access registers have unknown contents. 183 * Terminating task. 184 */ 185 kill_task = 1; 186 } 187 /* Revalidate control registers */ 188 if (!mci->cr) { 189 /* 190 * Control registers have unknown contents. 191 * Can't recover and therefore stopping machine. 192 */ 193 s390_handle_damage("invalid control registers."); 194 } else { 195 asm volatile( 196 " lctlg 0,15,0(%0)" 197 : : "a" (&S390_lowcore.cregs_save_area)); 198 } 199 /* 200 * We don't even try to revalidate the TOD register, since we simply 201 * can't write something sensible into that register. 202 */ 203 /* 204 * See if we can revalidate the TOD programmable register with its 205 * old contents (should be zero) otherwise set it to zero. 206 */ 207 if (!mci->pr) 208 asm volatile( 209 " sr 0,0\n" 210 " sckpf" 211 : : : "0", "cc"); 212 else 213 asm volatile( 214 " l 0,0(%0)\n" 215 " sckpf" 216 : : "a" (&S390_lowcore.tod_progreg_save_area) 217 : "0", "cc"); 218 /* Revalidate clock comparator register */ 219 set_clock_comparator(S390_lowcore.clock_comparator); 220 /* Check if old PSW is valid */ 221 if (!mci->wp) 222 /* 223 * Can't tell if we come from user or kernel mode 224 * -> stopping machine. 225 */ 226 s390_handle_damage("old psw invalid."); 227 228 if (!mci->ms || !mci->pm || !mci->ia) 229 kill_task = 1; 230 231 return kill_task; 232 } 233 234 #define MAX_IPD_COUNT 29 235 #define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */ 236 237 #define ED_STP_ISLAND 6 /* External damage STP island check */ 238 #define ED_STP_SYNC 7 /* External damage STP sync check */ 239 #define ED_ETR_SYNC 12 /* External damage ETR sync check */ 240 #define ED_ETR_SWITCH 13 /* External damage ETR switch to local */ 241 242 /* 243 * machine check handler. 244 */ 245 void notrace s390_do_machine_check(struct pt_regs *regs) 246 { 247 static int ipd_count; 248 static DEFINE_SPINLOCK(ipd_lock); 249 static unsigned long long last_ipd; 250 struct mcck_struct *mcck; 251 unsigned long long tmp; 252 struct mci *mci; 253 int umode; 254 255 nmi_enter(); 256 inc_irq_stat(NMI_NMI); 257 mci = (struct mci *) &S390_lowcore.mcck_interruption_code; 258 mcck = this_cpu_ptr(&cpu_mcck); 259 umode = user_mode(regs); 260 261 if (mci->sd) { 262 /* System damage -> stopping machine */ 263 s390_handle_damage("received system damage machine check."); 264 } 265 if (mci->pd) { 266 if (mci->b) { 267 /* Processing backup -> verify if we can survive this */ 268 u64 z_mcic, o_mcic, t_mcic; 269 z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29); 270 o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 | 271 1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 | 272 1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 | 273 1ULL<<16); 274 t_mcic = *(u64 *)mci; 275 276 if (((t_mcic & z_mcic) != 0) || 277 ((t_mcic & o_mcic) != o_mcic)) { 278 s390_handle_damage("processing backup machine " 279 "check with damage."); 280 } 281 282 /* 283 * Nullifying exigent condition, therefore we might 284 * retry this instruction. 285 */ 286 spin_lock(&ipd_lock); 287 tmp = get_tod_clock(); 288 if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME) 289 ipd_count++; 290 else 291 ipd_count = 1; 292 last_ipd = tmp; 293 if (ipd_count == MAX_IPD_COUNT) 294 s390_handle_damage("too many ipd retries."); 295 spin_unlock(&ipd_lock); 296 } else { 297 /* Processing damage -> stopping machine */ 298 s390_handle_damage("received instruction processing " 299 "damage machine check."); 300 } 301 } 302 if (s390_revalidate_registers(mci)) { 303 if (umode) { 304 /* 305 * Couldn't restore all register contents while in 306 * user mode -> mark task for termination. 307 */ 308 mcck->kill_task = 1; 309 mcck->mcck_code = *(unsigned long long *) mci; 310 set_cpu_flag(CIF_MCCK_PENDING); 311 } else { 312 /* 313 * Couldn't restore all register contents while in 314 * kernel mode -> stopping machine. 315 */ 316 s390_handle_damage("unable to revalidate registers."); 317 } 318 } 319 if (mci->cd) { 320 /* Timing facility damage */ 321 s390_handle_damage("TOD clock damaged"); 322 } 323 if (mci->ed && mci->ec) { 324 /* External damage */ 325 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC)) 326 etr_sync_check(); 327 if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH)) 328 etr_switch_to_local(); 329 if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC)) 330 stp_sync_check(); 331 if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND)) 332 stp_island_check(); 333 } 334 if (mci->se) 335 /* Storage error uncorrected */ 336 s390_handle_damage("received storage error uncorrected " 337 "machine check."); 338 if (mci->ke) 339 /* Storage key-error uncorrected */ 340 s390_handle_damage("received storage key-error uncorrected " 341 "machine check."); 342 if (mci->ds && mci->fa) 343 /* Storage degradation */ 344 s390_handle_damage("received storage degradation machine " 345 "check."); 346 if (mci->cp) { 347 /* Channel report word pending */ 348 mcck->channel_report = 1; 349 set_cpu_flag(CIF_MCCK_PENDING); 350 } 351 if (mci->w) { 352 /* Warning pending */ 353 mcck->warning = 1; 354 set_cpu_flag(CIF_MCCK_PENDING); 355 } 356 nmi_exit(); 357 } 358 359 static int __init machine_check_init(void) 360 { 361 ctl_set_bit(14, 25); /* enable external damage MCH */ 362 ctl_set_bit(14, 27); /* enable system recovery MCH */ 363 ctl_set_bit(14, 24); /* enable warning MCH */ 364 return 0; 365 } 366 early_initcall(machine_check_init); 367