1 /* 2 * Copyright (C) 2001 Dave Engebretsen IBM Corporation 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 */ 18 19 /* Change Activity: 20 * 2001/09/21 : engebret : Created with minimal EPOW and HW exception support. 21 * End Change Activity 22 */ 23 24 #include <linux/errno.h> 25 #include <linux/threads.h> 26 #include <linux/kernel_stat.h> 27 #include <linux/signal.h> 28 #include <linux/sched.h> 29 #include <linux/ioport.h> 30 #include <linux/interrupt.h> 31 #include <linux/timex.h> 32 #include <linux/init.h> 33 #include <linux/delay.h> 34 #include <linux/irq.h> 35 #include <linux/random.h> 36 #include <linux/sysrq.h> 37 #include <linux/bitops.h> 38 39 #include <asm/uaccess.h> 40 #include <asm/system.h> 41 #include <asm/io.h> 42 #include <asm/pgtable.h> 43 #include <asm/irq.h> 44 #include <asm/cache.h> 45 #include <asm/prom.h> 46 #include <asm/ptrace.h> 47 #include <asm/machdep.h> 48 #include <asm/rtas.h> 49 #include <asm/udbg.h> 50 #include <asm/firmware.h> 51 52 #include "pseries.h" 53 54 static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX]; 55 static DEFINE_SPINLOCK(ras_log_buf_lock); 56 57 static char global_mce_data_buf[RTAS_ERROR_LOG_MAX]; 58 static DEFINE_PER_CPU(__u64, mce_data_buf); 59 60 static int ras_get_sensor_state_token; 61 static int ras_check_exception_token; 62 63 #define EPOW_SENSOR_TOKEN 9 64 #define EPOW_SENSOR_INDEX 0 65 66 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id); 67 static irqreturn_t ras_error_interrupt(int irq, void *dev_id); 68 69 70 /* 71 * Initialize handlers for the set of interrupts caused by hardware errors 72 * and power system events. 73 */ 74 static int __init init_ras_IRQ(void) 75 { 76 struct device_node *np; 77 78 ras_get_sensor_state_token = rtas_token("get-sensor-state"); 79 ras_check_exception_token = rtas_token("check-exception"); 80 81 /* Internal Errors */ 82 np = of_find_node_by_path("/event-sources/internal-errors"); 83 if (np != NULL) { 84 request_event_sources_irqs(np, ras_error_interrupt, 85 "RAS_ERROR"); 86 of_node_put(np); 87 } 88 89 /* EPOW Events */ 90 np = of_find_node_by_path("/event-sources/epow-events"); 91 if (np != NULL) { 92 request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW"); 93 of_node_put(np); 94 } 95 96 return 0; 97 } 98 __initcall(init_ras_IRQ); 99 100 /* 101 * Handle power subsystem events (EPOW). 102 * 103 * Presently we just log the event has occurred. This should be fixed 104 * to examine the type of power failure and take appropriate action where 105 * the time horizon permits something useful to be done. 106 */ 107 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id) 108 { 109 int status = 0xdeadbeef; 110 int state = 0; 111 int critical; 112 113 status = rtas_call(ras_get_sensor_state_token, 2, 2, &state, 114 EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX); 115 116 if (state > 3) 117 critical = 1; /* Time Critical */ 118 else 119 critical = 0; 120 121 spin_lock(&ras_log_buf_lock); 122 123 status = rtas_call(ras_check_exception_token, 6, 1, NULL, 124 RTAS_VECTOR_EXTERNAL_INTERRUPT, 125 virq_to_hw(irq), 126 RTAS_EPOW_WARNING | RTAS_POWERMGM_EVENTS, 127 critical, __pa(&ras_log_buf), 128 rtas_get_error_log_max()); 129 130 udbg_printf("EPOW <0x%lx 0x%x 0x%x>\n", 131 *((unsigned long *)&ras_log_buf), status, state); 132 printk(KERN_WARNING "EPOW <0x%lx 0x%x 0x%x>\n", 133 *((unsigned long *)&ras_log_buf), status, state); 134 135 /* format and print the extended information */ 136 log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0); 137 138 spin_unlock(&ras_log_buf_lock); 139 return IRQ_HANDLED; 140 } 141 142 /* 143 * Handle hardware error interrupts. 144 * 145 * RTAS check-exception is called to collect data on the exception. If 146 * the error is deemed recoverable, we log a warning and return. 147 * For nonrecoverable errors, an error is logged and we stop all processing 148 * as quickly as possible in order to prevent propagation of the failure. 149 */ 150 static irqreturn_t ras_error_interrupt(int irq, void *dev_id) 151 { 152 struct rtas_error_log *rtas_elog; 153 int status = 0xdeadbeef; 154 int fatal; 155 156 spin_lock(&ras_log_buf_lock); 157 158 status = rtas_call(ras_check_exception_token, 6, 1, NULL, 159 RTAS_VECTOR_EXTERNAL_INTERRUPT, 160 virq_to_hw(irq), 161 RTAS_INTERNAL_ERROR, 1 /*Time Critical */, 162 __pa(&ras_log_buf), 163 rtas_get_error_log_max()); 164 165 rtas_elog = (struct rtas_error_log *)ras_log_buf; 166 167 if ((status == 0) && (rtas_elog->severity >= RTAS_SEVERITY_ERROR_SYNC)) 168 fatal = 1; 169 else 170 fatal = 0; 171 172 /* format and print the extended information */ 173 log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal); 174 175 if (fatal) { 176 udbg_printf("Fatal HW Error <0x%lx 0x%x>\n", 177 *((unsigned long *)&ras_log_buf), status); 178 printk(KERN_EMERG "Error: Fatal hardware error <0x%lx 0x%x>\n", 179 *((unsigned long *)&ras_log_buf), status); 180 181 #ifndef DEBUG_RTAS_POWER_OFF 182 /* Don't actually power off when debugging so we can test 183 * without actually failing while injecting errors. 184 * Error data will not be logged to syslog. 185 */ 186 ppc_md.power_off(); 187 #endif 188 } else { 189 udbg_printf("Recoverable HW Error <0x%lx 0x%x>\n", 190 *((unsigned long *)&ras_log_buf), status); 191 printk(KERN_WARNING 192 "Warning: Recoverable hardware error <0x%lx 0x%x>\n", 193 *((unsigned long *)&ras_log_buf), status); 194 } 195 196 spin_unlock(&ras_log_buf_lock); 197 return IRQ_HANDLED; 198 } 199 200 /* 201 * Some versions of FWNMI place the buffer inside the 4kB page starting at 202 * 0x7000. Other versions place it inside the rtas buffer. We check both. 203 */ 204 #define VALID_FWNMI_BUFFER(A) \ 205 ((((A) >= 0x7000) && ((A) < 0x7ff0)) || \ 206 (((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16)))) 207 208 /* 209 * Get the error information for errors coming through the 210 * FWNMI vectors. The pt_regs' r3 will be updated to reflect 211 * the actual r3 if possible, and a ptr to the error log entry 212 * will be returned if found. 213 * 214 * If the RTAS error is not of the extended type, then we put it in a per 215 * cpu 64bit buffer. If it is the extended type we use global_mce_data_buf. 216 * 217 * The global_mce_data_buf does not have any locks or protection around it, 218 * if a second machine check comes in, or a system reset is done 219 * before we have logged the error, then we will get corruption in the 220 * error log. This is preferable over holding off on calling 221 * ibm,nmi-interlock which would result in us checkstopping if a 222 * second machine check did come in. 223 */ 224 static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs) 225 { 226 unsigned long *savep; 227 struct rtas_error_log *h, *errhdr = NULL; 228 229 if (!VALID_FWNMI_BUFFER(regs->gpr[3])) { 230 printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]); 231 return NULL; 232 } 233 234 savep = __va(regs->gpr[3]); 235 regs->gpr[3] = savep[0]; /* restore original r3 */ 236 237 /* If it isn't an extended log we can use the per cpu 64bit buffer */ 238 h = (struct rtas_error_log *)&savep[1]; 239 if (!h->extended) { 240 memcpy(&__get_cpu_var(mce_data_buf), h, sizeof(__u64)); 241 errhdr = (struct rtas_error_log *)&__get_cpu_var(mce_data_buf); 242 } else { 243 int len; 244 245 len = max_t(int, 8+h->extended_log_length, RTAS_ERROR_LOG_MAX); 246 memset(global_mce_data_buf, 0, RTAS_ERROR_LOG_MAX); 247 memcpy(global_mce_data_buf, h, len); 248 errhdr = (struct rtas_error_log *)global_mce_data_buf; 249 } 250 251 return errhdr; 252 } 253 254 /* Call this when done with the data returned by FWNMI_get_errinfo. 255 * It will release the saved data area for other CPUs in the 256 * partition to receive FWNMI errors. 257 */ 258 static void fwnmi_release_errinfo(void) 259 { 260 int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL); 261 if (ret != 0) 262 printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret); 263 } 264 265 int pSeries_system_reset_exception(struct pt_regs *regs) 266 { 267 if (fwnmi_active) { 268 struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs); 269 if (errhdr) { 270 /* XXX Should look at FWNMI information */ 271 } 272 fwnmi_release_errinfo(); 273 } 274 return 0; /* need to perform reset */ 275 } 276 277 /* 278 * See if we can recover from a machine check exception. 279 * This is only called on power4 (or above) and only via 280 * the Firmware Non-Maskable Interrupts (fwnmi) handler 281 * which provides the error analysis for us. 282 * 283 * Return 1 if corrected (or delivered a signal). 284 * Return 0 if there is nothing we can do. 285 */ 286 static int recover_mce(struct pt_regs *regs, struct rtas_error_log *err) 287 { 288 int recovered = 0; 289 290 if (!(regs->msr & MSR_RI)) { 291 /* If MSR_RI isn't set, we cannot recover */ 292 recovered = 0; 293 294 } else if (err->disposition == RTAS_DISP_FULLY_RECOVERED) { 295 /* Platform corrected itself */ 296 recovered = 1; 297 298 } else if (err->disposition == RTAS_DISP_LIMITED_RECOVERY) { 299 /* Platform corrected itself but could be degraded */ 300 printk(KERN_ERR "MCE: limited recovery, system may " 301 "be degraded\n"); 302 recovered = 1; 303 304 } else if (user_mode(regs) && !is_global_init(current) && 305 err->severity == RTAS_SEVERITY_ERROR_SYNC) { 306 307 /* 308 * If we received a synchronous error when in userspace 309 * kill the task. Firmware may report details of the fail 310 * asynchronously, so we can't rely on the target and type 311 * fields being valid here. 312 */ 313 printk(KERN_ERR "MCE: uncorrectable error, killing task " 314 "%s:%d\n", current->comm, current->pid); 315 316 _exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip); 317 recovered = 1; 318 } 319 320 log_error((char *)err, ERR_TYPE_RTAS_LOG, 0); 321 322 return recovered; 323 } 324 325 /* 326 * Handle a machine check. 327 * 328 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi) 329 * should be present. If so the handler which called us tells us if the 330 * error was recovered (never true if RI=0). 331 * 332 * On hardware prior to Power 4 these exceptions were asynchronous which 333 * means we can't tell exactly where it occurred and so we can't recover. 334 */ 335 int pSeries_machine_check_exception(struct pt_regs *regs) 336 { 337 struct rtas_error_log *errp; 338 339 if (fwnmi_active) { 340 errp = fwnmi_get_errinfo(regs); 341 fwnmi_release_errinfo(); 342 if (errp && recover_mce(regs, errp)) 343 return 1; 344 } 345 346 return 0; 347 } 348