1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * ip28-berr.c: Bus error handling. 4 * 5 * Copyright (C) 2002, 2003 Ladislav Michl (ladis@linux-mips.org) 6 * Copyright (C) 2005 Peter Fuerst (pf@net.alphadv.de) - IP28 7 */ 8 9 #include <linux/init.h> 10 #include <linux/kernel.h> 11 #include <linux/sched.h> 12 #include <linux/sched/debug.h> 13 #include <linux/sched/signal.h> 14 #include <linux/seq_file.h> 15 16 #include <asm/addrspace.h> 17 #include <asm/traps.h> 18 #include <asm/branch.h> 19 #include <asm/irq_regs.h> 20 #include <asm/sgi/mc.h> 21 #include <asm/sgi/hpc3.h> 22 #include <asm/sgi/ioc.h> 23 #include <asm/sgi/ip22.h> 24 #include <asm/r4kcache.h> 25 #include <linux/uaccess.h> 26 #include <asm/bootinfo.h> 27 28 static unsigned int count_be_is_fixup; 29 static unsigned int count_be_handler; 30 static unsigned int count_be_interrupt; 31 static int debug_be_interrupt; 32 33 static unsigned int cpu_err_stat; /* Status reg for CPU */ 34 static unsigned int gio_err_stat; /* Status reg for GIO */ 35 static unsigned int cpu_err_addr; /* Error address reg for CPU */ 36 static unsigned int gio_err_addr; /* Error address reg for GIO */ 37 static unsigned int extio_stat; 38 static unsigned int hpc3_berr_stat; /* Bus error interrupt status */ 39 40 struct hpc3_stat { 41 unsigned long addr; 42 unsigned int ctrl; 43 unsigned int cbp; 44 unsigned int ndptr; 45 }; 46 47 static struct { 48 struct hpc3_stat pbdma[8]; 49 struct hpc3_stat scsi[2]; 50 struct hpc3_stat ethrx, ethtx; 51 } hpc3; 52 53 static struct { 54 unsigned long err_addr; 55 struct { 56 u32 lo; 57 u32 hi; 58 } tags[1][2], tagd[4][2], tagi[4][2]; /* Way 0/1 */ 59 } cache_tags; 60 61 static inline void save_cache_tags(unsigned busaddr) 62 { 63 unsigned long addr = CAC_BASE | busaddr; 64 int i; 65 cache_tags.err_addr = addr; 66 67 /* 68 * Starting with a bus-address, save secondary cache (indexed by 69 * PA[23..18:7..6]) tags first. 70 */ 71 addr &= ~1L; 72 #define tag cache_tags.tags[0] 73 cache_op(Index_Load_Tag_S, addr); 74 tag[0].lo = read_c0_taglo(); /* PA[35:18], VA[13:12] */ 75 tag[0].hi = read_c0_taghi(); /* PA[39:36] */ 76 cache_op(Index_Load_Tag_S, addr | 1L); 77 tag[1].lo = read_c0_taglo(); /* PA[35:18], VA[13:12] */ 78 tag[1].hi = read_c0_taghi(); /* PA[39:36] */ 79 #undef tag 80 81 /* 82 * Save all primary data cache (indexed by VA[13:5]) tags which 83 * might fit to this bus-address, knowing that VA[11:0] == PA[11:0]. 84 * Saving all tags and evaluating them later is easier and safer 85 * than relying on VA[13:12] from the secondary cache tags to pick 86 * matching primary tags here already. 87 */ 88 addr &= (0xffL << 56) | ((1 << 12) - 1); 89 #define tag cache_tags.tagd[i] 90 for (i = 0; i < 4; ++i, addr += (1 << 12)) { 91 cache_op(Index_Load_Tag_D, addr); 92 tag[0].lo = read_c0_taglo(); /* PA[35:12] */ 93 tag[0].hi = read_c0_taghi(); /* PA[39:36] */ 94 cache_op(Index_Load_Tag_D, addr | 1L); 95 tag[1].lo = read_c0_taglo(); /* PA[35:12] */ 96 tag[1].hi = read_c0_taghi(); /* PA[39:36] */ 97 } 98 #undef tag 99 100 /* 101 * Save primary instruction cache (indexed by VA[13:6]) tags 102 * the same way. 103 */ 104 addr &= (0xffL << 56) | ((1 << 12) - 1); 105 #define tag cache_tags.tagi[i] 106 for (i = 0; i < 4; ++i, addr += (1 << 12)) { 107 cache_op(Index_Load_Tag_I, addr); 108 tag[0].lo = read_c0_taglo(); /* PA[35:12] */ 109 tag[0].hi = read_c0_taghi(); /* PA[39:36] */ 110 cache_op(Index_Load_Tag_I, addr | 1L); 111 tag[1].lo = read_c0_taglo(); /* PA[35:12] */ 112 tag[1].hi = read_c0_taghi(); /* PA[39:36] */ 113 } 114 #undef tag 115 } 116 117 #define GIO_ERRMASK 0xff00 118 #define CPU_ERRMASK 0x3f00 119 120 static void save_and_clear_buserr(void) 121 { 122 int i; 123 124 /* save status registers */ 125 cpu_err_addr = sgimc->cerr; 126 cpu_err_stat = sgimc->cstat; 127 gio_err_addr = sgimc->gerr; 128 gio_err_stat = sgimc->gstat; 129 extio_stat = sgioc->extio; 130 hpc3_berr_stat = hpc3c0->bestat; 131 132 hpc3.scsi[0].addr = (unsigned long)&hpc3c0->scsi_chan0; 133 hpc3.scsi[0].ctrl = hpc3c0->scsi_chan0.ctrl; /* HPC3_SCTRL_ACTIVE ? */ 134 hpc3.scsi[0].cbp = hpc3c0->scsi_chan0.cbptr; 135 hpc3.scsi[0].ndptr = hpc3c0->scsi_chan0.ndptr; 136 137 hpc3.scsi[1].addr = (unsigned long)&hpc3c0->scsi_chan1; 138 hpc3.scsi[1].ctrl = hpc3c0->scsi_chan1.ctrl; /* HPC3_SCTRL_ACTIVE ? */ 139 hpc3.scsi[1].cbp = hpc3c0->scsi_chan1.cbptr; 140 hpc3.scsi[1].ndptr = hpc3c0->scsi_chan1.ndptr; 141 142 hpc3.ethrx.addr = (unsigned long)&hpc3c0->ethregs.rx_cbptr; 143 hpc3.ethrx.ctrl = hpc3c0->ethregs.rx_ctrl; /* HPC3_ERXCTRL_ACTIVE ? */ 144 hpc3.ethrx.cbp = hpc3c0->ethregs.rx_cbptr; 145 hpc3.ethrx.ndptr = hpc3c0->ethregs.rx_ndptr; 146 147 hpc3.ethtx.addr = (unsigned long)&hpc3c0->ethregs.tx_cbptr; 148 hpc3.ethtx.ctrl = hpc3c0->ethregs.tx_ctrl; /* HPC3_ETXCTRL_ACTIVE ? */ 149 hpc3.ethtx.cbp = hpc3c0->ethregs.tx_cbptr; 150 hpc3.ethtx.ndptr = hpc3c0->ethregs.tx_ndptr; 151 152 for (i = 0; i < 8; ++i) { 153 /* HPC3_PDMACTRL_ISACT ? */ 154 hpc3.pbdma[i].addr = (unsigned long)&hpc3c0->pbdma[i]; 155 hpc3.pbdma[i].ctrl = hpc3c0->pbdma[i].pbdma_ctrl; 156 hpc3.pbdma[i].cbp = hpc3c0->pbdma[i].pbdma_bptr; 157 hpc3.pbdma[i].ndptr = hpc3c0->pbdma[i].pbdma_dptr; 158 } 159 i = 0; 160 if (gio_err_stat & CPU_ERRMASK) 161 i = gio_err_addr; 162 if (cpu_err_stat & CPU_ERRMASK) 163 i = cpu_err_addr; 164 save_cache_tags(i); 165 166 sgimc->cstat = sgimc->gstat = 0; 167 } 168 169 static void print_cache_tags(void) 170 { 171 u32 scb, scw; 172 int i; 173 174 printk(KERN_ERR "Cache tags @ %08x:\n", (unsigned)cache_tags.err_addr); 175 176 /* PA[31:12] shifted to PTag0 (PA[35:12]) format */ 177 scw = (cache_tags.err_addr >> 4) & 0x0fffff00; 178 179 scb = cache_tags.err_addr & ((1 << 12) - 1) & ~((1 << 5) - 1); 180 for (i = 0; i < 4; ++i) { /* for each possible VA[13:12] value */ 181 if ((cache_tags.tagd[i][0].lo & 0x0fffff00) != scw && 182 (cache_tags.tagd[i][1].lo & 0x0fffff00) != scw) 183 continue; 184 printk(KERN_ERR 185 "D: 0: %08x %08x, 1: %08x %08x (VA[13:5] %04x)\n", 186 cache_tags.tagd[i][0].hi, cache_tags.tagd[i][0].lo, 187 cache_tags.tagd[i][1].hi, cache_tags.tagd[i][1].lo, 188 scb | (1 << 12)*i); 189 } 190 scb = cache_tags.err_addr & ((1 << 12) - 1) & ~((1 << 6) - 1); 191 for (i = 0; i < 4; ++i) { /* for each possible VA[13:12] value */ 192 if ((cache_tags.tagi[i][0].lo & 0x0fffff00) != scw && 193 (cache_tags.tagi[i][1].lo & 0x0fffff00) != scw) 194 continue; 195 printk(KERN_ERR 196 "I: 0: %08x %08x, 1: %08x %08x (VA[13:6] %04x)\n", 197 cache_tags.tagi[i][0].hi, cache_tags.tagi[i][0].lo, 198 cache_tags.tagi[i][1].hi, cache_tags.tagi[i][1].lo, 199 scb | (1 << 12)*i); 200 } 201 i = read_c0_config(); 202 scb = i & (1 << 13) ? 7:6; /* scblksize = 2^[7..6] */ 203 scw = ((i >> 16) & 7) + 19 - 1; /* scwaysize = 2^[24..19] / 2 */ 204 205 i = ((1 << scw) - 1) & ~((1 << scb) - 1); 206 printk(KERN_ERR "S: 0: %08x %08x, 1: %08x %08x (PA[%u:%u] %05x)\n", 207 cache_tags.tags[0][0].hi, cache_tags.tags[0][0].lo, 208 cache_tags.tags[0][1].hi, cache_tags.tags[0][1].lo, 209 scw-1, scb, i & (unsigned)cache_tags.err_addr); 210 } 211 212 static inline const char *cause_excode_text(int cause) 213 { 214 static const char *txt[32] = 215 { "Interrupt", 216 "TLB modification", 217 "TLB (load or instruction fetch)", 218 "TLB (store)", 219 "Address error (load or instruction fetch)", 220 "Address error (store)", 221 "Bus error (instruction fetch)", 222 "Bus error (data: load or store)", 223 "Syscall", 224 "Breakpoint", 225 "Reserved instruction", 226 "Coprocessor unusable", 227 "Arithmetic Overflow", 228 "Trap", 229 "14", 230 "Floating-Point", 231 "16", "17", "18", "19", "20", "21", "22", 232 "Watch Hi/Lo", 233 "24", "25", "26", "27", "28", "29", "30", "31", 234 }; 235 return txt[(cause & 0x7c) >> 2]; 236 } 237 238 static void print_buserr(const struct pt_regs *regs) 239 { 240 const int field = 2 * sizeof(unsigned long); 241 int error = 0; 242 243 if (extio_stat & EXTIO_MC_BUSERR) { 244 printk(KERN_ERR "MC Bus Error\n"); 245 error |= 1; 246 } 247 if (extio_stat & EXTIO_HPC3_BUSERR) { 248 printk(KERN_ERR "HPC3 Bus Error 0x%x:<id=0x%x,%s,lane=0x%x>\n", 249 hpc3_berr_stat, 250 (hpc3_berr_stat & HPC3_BESTAT_PIDMASK) >> 251 HPC3_BESTAT_PIDSHIFT, 252 (hpc3_berr_stat & HPC3_BESTAT_CTYPE) ? "PIO" : "DMA", 253 hpc3_berr_stat & HPC3_BESTAT_BLMASK); 254 error |= 2; 255 } 256 if (extio_stat & EXTIO_EISA_BUSERR) { 257 printk(KERN_ERR "EISA Bus Error\n"); 258 error |= 4; 259 } 260 if (cpu_err_stat & CPU_ERRMASK) { 261 printk(KERN_ERR "CPU error 0x%x<%s%s%s%s%s%s> @ 0x%08x\n", 262 cpu_err_stat, 263 cpu_err_stat & SGIMC_CSTAT_RD ? "RD " : "", 264 cpu_err_stat & SGIMC_CSTAT_PAR ? "PAR " : "", 265 cpu_err_stat & SGIMC_CSTAT_ADDR ? "ADDR " : "", 266 cpu_err_stat & SGIMC_CSTAT_SYSAD_PAR ? "SYSAD " : "", 267 cpu_err_stat & SGIMC_CSTAT_SYSCMD_PAR ? "SYSCMD " : "", 268 cpu_err_stat & SGIMC_CSTAT_BAD_DATA ? "BAD_DATA " : "", 269 cpu_err_addr); 270 error |= 8; 271 } 272 if (gio_err_stat & GIO_ERRMASK) { 273 printk(KERN_ERR "GIO error 0x%x:<%s%s%s%s%s%s%s%s> @ 0x%08x\n", 274 gio_err_stat, 275 gio_err_stat & SGIMC_GSTAT_RD ? "RD " : "", 276 gio_err_stat & SGIMC_GSTAT_WR ? "WR " : "", 277 gio_err_stat & SGIMC_GSTAT_TIME ? "TIME " : "", 278 gio_err_stat & SGIMC_GSTAT_PROM ? "PROM " : "", 279 gio_err_stat & SGIMC_GSTAT_ADDR ? "ADDR " : "", 280 gio_err_stat & SGIMC_GSTAT_BC ? "BC " : "", 281 gio_err_stat & SGIMC_GSTAT_PIO_RD ? "PIO_RD " : "", 282 gio_err_stat & SGIMC_GSTAT_PIO_WR ? "PIO_WR " : "", 283 gio_err_addr); 284 error |= 16; 285 } 286 if (!error) 287 printk(KERN_ERR "MC: Hmm, didn't find any error condition.\n"); 288 else { 289 printk(KERN_ERR "CP0: config %08x, " 290 "MC: cpuctrl0/1: %08x/%05x, giopar: %04x\n" 291 "MC: cpu/gio_memacc: %08x/%05x, memcfg0/1: %08x/%08x\n", 292 read_c0_config(), 293 sgimc->cpuctrl0, sgimc->cpuctrl0, sgimc->giopar, 294 sgimc->cmacc, sgimc->gmacc, 295 sgimc->mconfig0, sgimc->mconfig1); 296 print_cache_tags(); 297 } 298 printk(KERN_ALERT "%s, epc == %0*lx, ra == %0*lx\n", 299 cause_excode_text(regs->cp0_cause), 300 field, regs->cp0_epc, field, regs->regs[31]); 301 } 302 303 /* 304 * Check, whether MC's (virtual) DMA address caused the bus error. 305 * See "Virtual DMA Specification", Draft 1.5, Feb 13 1992, SGI 306 */ 307 308 static int addr_is_ram(unsigned long addr, unsigned sz) 309 { 310 int i; 311 312 for (i = 0; i < boot_mem_map.nr_map; i++) { 313 unsigned long a = boot_mem_map.map[i].addr; 314 if (a <= addr && addr+sz <= a+boot_mem_map.map[i].size) 315 return 1; 316 } 317 return 0; 318 } 319 320 static int check_microtlb(u32 hi, u32 lo, unsigned long vaddr) 321 { 322 /* This is likely rather similar to correct code ;-) */ 323 324 vaddr &= 0x7fffffff; /* Doc. states that top bit is ignored */ 325 326 /* If tlb-entry is valid and VPN-high (bits [30:21] ?) matches... */ 327 if ((lo & 2) && (vaddr >> 21) == ((hi<<1) >> 22)) { 328 u32 ctl = sgimc->dma_ctrl; 329 if (ctl & 1) { 330 unsigned int pgsz = (ctl & 2) ? 14:12; /* 16k:4k */ 331 /* PTEIndex is VPN-low (bits [22:14]/[20:12] ?) */ 332 unsigned long pte = (lo >> 6) << 12; /* PTEBase */ 333 pte += 8*((vaddr >> pgsz) & 0x1ff); 334 if (addr_is_ram(pte, 8)) { 335 /* 336 * Note: Since DMA hardware does look up 337 * translation on its own, this PTE *must* 338 * match the TLB/EntryLo-register format ! 339 */ 340 unsigned long a = *(unsigned long *) 341 PHYS_TO_XKSEG_UNCACHED(pte); 342 a = (a & 0x3f) << 6; /* PFN */ 343 a += vaddr & ((1 << pgsz) - 1); 344 return cpu_err_addr == a; 345 } 346 } 347 } 348 return 0; 349 } 350 351 static int check_vdma_memaddr(void) 352 { 353 if (cpu_err_stat & CPU_ERRMASK) { 354 u32 a = sgimc->maddronly; 355 356 if (!(sgimc->dma_ctrl & 0x100)) /* Xlate-bit clear ? */ 357 return cpu_err_addr == a; 358 359 if (check_microtlb(sgimc->dtlb_hi0, sgimc->dtlb_lo0, a) || 360 check_microtlb(sgimc->dtlb_hi1, sgimc->dtlb_lo1, a) || 361 check_microtlb(sgimc->dtlb_hi2, sgimc->dtlb_lo2, a) || 362 check_microtlb(sgimc->dtlb_hi3, sgimc->dtlb_lo3, a)) 363 return 1; 364 } 365 return 0; 366 } 367 368 static int check_vdma_gioaddr(void) 369 { 370 if (gio_err_stat & GIO_ERRMASK) { 371 u32 a = sgimc->gio_dma_trans; 372 a = (sgimc->gmaddronly & ~a) | (sgimc->gio_dma_sbits & a); 373 return gio_err_addr == a; 374 } 375 return 0; 376 } 377 378 /* 379 * MC sends an interrupt whenever bus or parity errors occur. In addition, 380 * if the error happened during a CPU read, it also asserts the bus error 381 * pin on the R4K. Code in bus error handler save the MC bus error registers 382 * and then clear the interrupt when this happens. 383 */ 384 385 static int ip28_be_interrupt(const struct pt_regs *regs) 386 { 387 int i; 388 389 save_and_clear_buserr(); 390 /* 391 * Try to find out, whether we got here by a mispredicted speculative 392 * load/store operation. If so, it's not fatal, we can go on. 393 */ 394 /* Any cause other than "Interrupt" (ExcCode 0) is fatal. */ 395 if (regs->cp0_cause & CAUSEF_EXCCODE) 396 goto mips_be_fatal; 397 398 /* Any cause other than "Bus error interrupt" (IP6) is weird. */ 399 if ((regs->cp0_cause & CAUSEF_IP6) != CAUSEF_IP6) 400 goto mips_be_fatal; 401 402 if (extio_stat & (EXTIO_HPC3_BUSERR | EXTIO_EISA_BUSERR)) 403 goto mips_be_fatal; 404 405 /* Any state other than "Memory bus error" is fatal. */ 406 if (cpu_err_stat & CPU_ERRMASK & ~SGIMC_CSTAT_ADDR) 407 goto mips_be_fatal; 408 409 /* GIO errors other than timeouts are fatal */ 410 if (gio_err_stat & GIO_ERRMASK & ~SGIMC_GSTAT_TIME) 411 goto mips_be_fatal; 412 413 /* 414 * Now we have an asynchronous bus error, speculatively or DMA caused. 415 * Need to search all DMA descriptors for the error address. 416 */ 417 for (i = 0; i < sizeof(hpc3)/sizeof(struct hpc3_stat); ++i) { 418 struct hpc3_stat *hp = (struct hpc3_stat *)&hpc3 + i; 419 if ((cpu_err_stat & CPU_ERRMASK) && 420 (cpu_err_addr == hp->ndptr || cpu_err_addr == hp->cbp)) 421 break; 422 if ((gio_err_stat & GIO_ERRMASK) && 423 (gio_err_addr == hp->ndptr || gio_err_addr == hp->cbp)) 424 break; 425 } 426 if (i < sizeof(hpc3)/sizeof(struct hpc3_stat)) { 427 struct hpc3_stat *hp = (struct hpc3_stat *)&hpc3 + i; 428 printk(KERN_ERR "at DMA addresses: HPC3 @ %08lx:" 429 " ctl %08x, ndp %08x, cbp %08x\n", 430 CPHYSADDR(hp->addr), hp->ctrl, hp->ndptr, hp->cbp); 431 goto mips_be_fatal; 432 } 433 /* Check MC's virtual DMA stuff. */ 434 if (check_vdma_memaddr()) { 435 printk(KERN_ERR "at GIO DMA: mem address 0x%08x.\n", 436 sgimc->maddronly); 437 goto mips_be_fatal; 438 } 439 if (check_vdma_gioaddr()) { 440 printk(KERN_ERR "at GIO DMA: gio address 0x%08x.\n", 441 sgimc->gmaddronly); 442 goto mips_be_fatal; 443 } 444 /* A speculative bus error... */ 445 if (debug_be_interrupt) { 446 print_buserr(regs); 447 printk(KERN_ERR "discarded!\n"); 448 } 449 return MIPS_BE_DISCARD; 450 451 mips_be_fatal: 452 print_buserr(regs); 453 return MIPS_BE_FATAL; 454 } 455 456 void ip22_be_interrupt(int irq) 457 { 458 struct pt_regs *regs = get_irq_regs(); 459 460 count_be_interrupt++; 461 462 if (ip28_be_interrupt(regs) != MIPS_BE_DISCARD) { 463 /* Assume it would be too dangerous to continue ... */ 464 die_if_kernel("Oops", regs); 465 force_sig(SIGBUS, current); 466 } else if (debug_be_interrupt) 467 show_regs((struct pt_regs *)regs); 468 } 469 470 static int ip28_be_handler(struct pt_regs *regs, int is_fixup) 471 { 472 /* 473 * We arrive here only in the unusual case of do_be() invocation, 474 * i.e. by a bus error exception without a bus error interrupt. 475 */ 476 if (is_fixup) { 477 count_be_is_fixup++; 478 save_and_clear_buserr(); 479 return MIPS_BE_FIXUP; 480 } 481 count_be_handler++; 482 return ip28_be_interrupt(regs); 483 } 484 485 void __init ip22_be_init(void) 486 { 487 board_be_handler = ip28_be_handler; 488 } 489 490 int ip28_show_be_info(struct seq_file *m) 491 { 492 seq_printf(m, "IP28 be fixups\t\t: %u\n", count_be_is_fixup); 493 seq_printf(m, "IP28 be interrupts\t: %u\n", count_be_interrupt); 494 seq_printf(m, "IP28 be handler\t\t: %u\n", count_be_handler); 495 496 return 0; 497 } 498 499 static int __init debug_be_setup(char *str) 500 { 501 debug_be_interrupt++; 502 return 1; 503 } 504 __setup("ip28_debug_be", debug_be_setup); 505