arch/x86/platform/uv/uv_nmi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * SGI NMI support routines
   4  *
   5  * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
   6  * Copyright (C) 2007-2017 Silicon Graphics, Inc. All rights reserved.
   7  * Copyright (c) Mike Travis
   8  */
   9
  10 #include <linux/cpu.h>
  11 #include <linux/delay.h>
  12 #include <linux/kdb.h>
  13 #include <linux/kexec.h>
  14 #include <linux/kgdb.h>
  15 #include <linux/moduleparam.h>
  16 #include <linux/nmi.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/debug.h>
  19 #include <linux/slab.h>
  20 #include <linux/clocksource.h>
  21
  22 #include <asm/apic.h>
  23 #include <asm/current.h>
  24 #include <asm/kdebug.h>
  25 #include <asm/local64.h>
  26 #include <asm/nmi.h>
  27 #include <asm/reboot.h>
  28 #include <asm/traps.h>
  29 #include <asm/uv/uv.h>
  30 #include <asm/uv/uv_hub.h>
  31 #include <asm/uv/uv_mmrs.h>
  32
  33 /*
  34  * UV handler for NMI
  35  *
  36  * Handle system-wide NMI events generated by the global 'power nmi' command.
  37  *
  38  * Basic operation is to field the NMI interrupt on each CPU and wait
  39  * until all CPU's have arrived into the nmi handler.  If some CPU's do not
  40  * make it into the handler, try and force them in with the IPI(NMI) signal.
  41  *
  42  * We also have to lessen UV Hub MMR accesses as much as possible as this
  43  * disrupts the UV Hub's primary mission of directing NumaLink traffic and
  44  * can cause system problems to occur.
  45  *
  46  * To do this we register our primary NMI notifier on the NMI_UNKNOWN
  47  * chain.  This reduces the number of false NMI calls when the perf
  48  * tools are running which generate an enormous number of NMIs per
  49  * second (~4M/s for 1024 CPU threads).  Our secondary NMI handler is
  50  * very short as it only checks that if it has been "pinged" with the
  51  * IPI(NMI) signal as mentioned above, and does not read the UV Hub's MMR.
  52  *
  53  */
  54
  55 static struct uv_hub_nmi_s **uv_hub_nmi_list;
  56
  57 DEFINE_PER_CPU(struct uv_cpu_nmi_s, uv_cpu_nmi);
  58
  59 /* Newer SMM NMI handler, not present in all systems */
  60 static unsigned long uvh_nmi_mmrx;              /* UVH_EVENT_OCCURRED0/1 */
  61 static unsigned long uvh_nmi_mmrx_clear;        /* UVH_EVENT_OCCURRED0/1_ALIAS */
  62 static int uvh_nmi_mmrx_shift;                  /* UVH_EVENT_OCCURRED0/1_EXTIO_INT0_SHFT */
  63 static char *uvh_nmi_mmrx_type;                 /* "EXTIO_INT0" */
  64
  65 /* Non-zero indicates newer SMM NMI handler present */
  66 static unsigned long uvh_nmi_mmrx_supported;    /* UVH_EXTIO_INT0_BROADCAST */
  67
  68 /* Indicates to BIOS that we want to use the newer SMM NMI handler */
  69 static unsigned long uvh_nmi_mmrx_req;          /* UVH_BIOS_KERNEL_MMR_ALIAS_2 */
  70 static int uvh_nmi_mmrx_req_shift;              /* 62 */
  71
  72 /* UV hubless values */
  73 #define NMI_CONTROL_PORT        0x70
  74 #define NMI_DUMMY_PORT          0x71
  75 #define PAD_OWN_GPP_D_0         0x2c
  76 #define GPI_NMI_STS_GPP_D_0     0x164
  77 #define GPI_NMI_ENA_GPP_D_0     0x174
  78 #define STS_GPP_D_0_MASK        0x1
  79 #define PAD_CFG_DW0_GPP_D_0     0x4c0
  80 #define GPIROUTNMI              (1ul << 17)
  81 #define PCH_PCR_GPIO_1_BASE     0xfdae0000ul
  82 #define PCH_PCR_GPIO_ADDRESS(offset) (int *)((u64)(pch_base) | (u64)(offset))
  83
  84 static u64 *pch_base;
  85 static unsigned long nmi_mmr;
  86 static unsigned long nmi_mmr_clear;
  87 static unsigned long nmi_mmr_pending;
  88
  89 static atomic_t uv_in_nmi;
  90 static atomic_t uv_nmi_cpu = ATOMIC_INIT(-1);
  91 static atomic_t uv_nmi_cpus_in_nmi = ATOMIC_INIT(-1);
  92 static atomic_t uv_nmi_slave_continue;
  93 static cpumask_var_t uv_nmi_cpu_mask;
  94
  95 static atomic_t uv_nmi_kexec_failed;
  96
  97 /* Values for uv_nmi_slave_continue */
  98 #define SLAVE_CLEAR     0
  99 #define SLAVE_CONTINUE  1
 100 #define SLAVE_EXIT      2
 101
 102 /*
 103  * Default is all stack dumps go to the console and buffer.
 104  * Lower level to send to log buffer only.
 105  */
 106 static int uv_nmi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
 107 module_param_named(dump_loglevel, uv_nmi_loglevel, int, 0644);
 108
 109 /*
 110  * The following values show statistics on how perf events are affecting
 111  * this system.
 112  */
 113 static int param_get_local64(char *buffer, const struct kernel_param *kp)
 114 {
 115         return sprintf(buffer, "%lu\n", local64_read((local64_t *)kp->arg));
 116 }
 117
 118 static int param_set_local64(const char *val, const struct kernel_param *kp)
 119 {
 120         /* Clear on any write */
 121         local64_set((local64_t *)kp->arg, 0);
 122         return 0;
 123 }
 124
 125 static const struct kernel_param_ops param_ops_local64 = {
 126         .get = param_get_local64,
 127         .set = param_set_local64,
 128 };
 129 #define param_check_local64(name, p) __param_check(name, p, local64_t)
 130
 131 static local64_t uv_nmi_count;
 132 module_param_named(nmi_count, uv_nmi_count, local64, 0644);
 133
 134 static local64_t uv_nmi_misses;
 135 module_param_named(nmi_misses, uv_nmi_misses, local64, 0644);
 136
 137 static local64_t uv_nmi_ping_count;
 138 module_param_named(ping_count, uv_nmi_ping_count, local64, 0644);
 139
 140 static local64_t uv_nmi_ping_misses;
 141 module_param_named(ping_misses, uv_nmi_ping_misses, local64, 0644);
 142
 143 /*
 144  * Following values allow tuning for large systems under heavy loading
 145  */
 146 static int uv_nmi_initial_delay = 100;
 147 module_param_named(initial_delay, uv_nmi_initial_delay, int, 0644);
 148
 149 static int uv_nmi_slave_delay = 100;
 150 module_param_named(slave_delay, uv_nmi_slave_delay, int, 0644);
 151
 152 static int uv_nmi_loop_delay = 100;
 153 module_param_named(loop_delay, uv_nmi_loop_delay, int, 0644);
 154
 155 static int uv_nmi_trigger_delay = 10000;
 156 module_param_named(trigger_delay, uv_nmi_trigger_delay, int, 0644);
 157
 158 static int uv_nmi_wait_count = 100;
 159 module_param_named(wait_count, uv_nmi_wait_count, int, 0644);
 160
 161 static int uv_nmi_retry_count = 500;
 162 module_param_named(retry_count, uv_nmi_retry_count, int, 0644);
 163
 164 static bool uv_pch_intr_enable = true;
 165 static bool uv_pch_intr_now_enabled;
 166 module_param_named(pch_intr_enable, uv_pch_intr_enable, bool, 0644);
 167
 168 static bool uv_pch_init_enable = true;
 169 module_param_named(pch_init_enable, uv_pch_init_enable, bool, 0644);
 170
 171 static int uv_nmi_debug;
 172 module_param_named(debug, uv_nmi_debug, int, 0644);
 173
 174 #define nmi_debug(fmt, ...)                             \
 175         do {                                            \
 176                 if (uv_nmi_debug)                       \
 177                         pr_info(fmt, ##__VA_ARGS__);    \
 178         } while (0)
 179
 180 /* Valid NMI Actions */
 181 #define ACTION_LEN      16
 182 static struct nmi_action {
 183         char    *action;
 184         char    *desc;
 185 } valid_acts[] = {
 186         {       "kdump",        "do kernel crash dump"                  },
 187         {       "dump",         "dump process stack for each cpu"       },
 188         {       "ips",          "dump Inst Ptr info for each cpu"       },
 189         {       "kdb",          "enter KDB (needs kgdboc= assignment)"  },
 190         {       "kgdb",         "enter KGDB (needs gdb target remote)"  },
 191         {       "health",       "check if CPUs respond to NMI"          },
 192 };
 193 typedef char action_t[ACTION_LEN];
 194 static action_t uv_nmi_action = { "dump" };
 195
 196 static int param_get_action(char *buffer, const struct kernel_param *kp)
 197 {
 198         return sprintf(buffer, "%s\n", uv_nmi_action);
 199 }
 200
 201 static int param_set_action(const char *val, const struct kernel_param *kp)
 202 {
 203         int i;
 204         int n = ARRAY_SIZE(valid_acts);
 205         char arg[ACTION_LEN], *p;
 206
 207         /* (remove possible '\n') */
 208         strncpy(arg, val, ACTION_LEN - 1);
 209         arg[ACTION_LEN - 1] = '\0';
 210         p = strchr(arg, '\n');
 211         if (p)
 212                 *p = '\0';
 213
 214         for (i = 0; i < n; i++)
 215                 if (!strcmp(arg, valid_acts[i].action))
 216                         break;
 217
 218         if (i < n) {
 219                 strcpy(uv_nmi_action, arg);
 220                 pr_info("UV: New NMI action:%s\n", uv_nmi_action);
 221                 return 0;
 222         }
 223
 224         pr_err("UV: Invalid NMI action:%s, valid actions are:\n", arg);
 225         for (i = 0; i < n; i++)
 226                 pr_err("UV: %-8s - %s\n",
 227                         valid_acts[i].action, valid_acts[i].desc);
 228         return -EINVAL;
 229 }
 230
 231 static const struct kernel_param_ops param_ops_action = {
 232         .get = param_get_action,
 233         .set = param_set_action,
 234 };
 235 #define param_check_action(name, p) __param_check(name, p, action_t)
 236
 237 module_param_named(action, uv_nmi_action, action, 0644);
 238
 239 static inline bool uv_nmi_action_is(const char *action)
 240 {
 241         return (strncmp(uv_nmi_action, action, strlen(action)) == 0);
 242 }
 243
 244 /* Setup which NMI support is present in system */
 245 static void uv_nmi_setup_mmrs(void)
 246 {
 247         /* First determine arch specific MMRs to handshake with BIOS */
 248         if (UVH_EVENT_OCCURRED0_EXTIO_INT0_MASK) {
 249                 uvh_nmi_mmrx = UVH_EVENT_OCCURRED0;
 250                 uvh_nmi_mmrx_clear = UVH_EVENT_OCCURRED0_ALIAS;
 251                 uvh_nmi_mmrx_shift = UVH_EVENT_OCCURRED0_EXTIO_INT0_SHFT;
 252                 uvh_nmi_mmrx_type = "OCRD0-EXTIO_INT0";
 253
 254                 uvh_nmi_mmrx_supported = UVH_EXTIO_INT0_BROADCAST;
 255                 uvh_nmi_mmrx_req = UVH_BIOS_KERNEL_MMR_ALIAS_2;
 256                 uvh_nmi_mmrx_req_shift = 62;
 257
 258         } else if (UVH_EVENT_OCCURRED1_EXTIO_INT0_MASK) {
 259                 uvh_nmi_mmrx = UVH_EVENT_OCCURRED1;
 260                 uvh_nmi_mmrx_clear = UVH_EVENT_OCCURRED1_ALIAS;
 261                 uvh_nmi_mmrx_shift = UVH_EVENT_OCCURRED1_EXTIO_INT0_SHFT;
 262                 uvh_nmi_mmrx_type = "OCRD1-EXTIO_INT0";
 263
 264                 uvh_nmi_mmrx_supported = UVH_EXTIO_INT0_BROADCAST;
 265                 uvh_nmi_mmrx_req = UVH_BIOS_KERNEL_MMR_ALIAS_2;
 266                 uvh_nmi_mmrx_req_shift = 62;
 267
 268         } else {
 269                 pr_err("UV:%s:cannot find EVENT_OCCURRED*_EXTIO_INT0\n",
 270                         __func__);
 271                 return;
 272         }
 273
 274         /* Then find out if new NMI is supported */
 275         if (likely(uv_read_local_mmr(uvh_nmi_mmrx_supported))) {
 276                 uv_write_local_mmr(uvh_nmi_mmrx_req,
 277                                         1UL << uvh_nmi_mmrx_req_shift);
 278                 nmi_mmr = uvh_nmi_mmrx;
 279                 nmi_mmr_clear = uvh_nmi_mmrx_clear;
 280                 nmi_mmr_pending = 1UL << uvh_nmi_mmrx_shift;
 281                 pr_info("UV: SMI NMI support: %s\n", uvh_nmi_mmrx_type);
 282         } else {
 283                 nmi_mmr = UVH_NMI_MMR;
 284                 nmi_mmr_clear = UVH_NMI_MMR_CLEAR;
 285                 nmi_mmr_pending = 1UL << UVH_NMI_MMR_SHIFT;
 286                 pr_info("UV: SMI NMI support: %s\n", UVH_NMI_MMR_TYPE);
 287         }
 288 }
 289
 290 /* Read NMI MMR and check if NMI flag was set by BMC. */
 291 static inline int uv_nmi_test_mmr(struct uv_hub_nmi_s *hub_nmi)
 292 {
 293         hub_nmi->nmi_value = uv_read_local_mmr(nmi_mmr);
 294         atomic_inc(&hub_nmi->read_mmr_count);
 295         return !!(hub_nmi->nmi_value & nmi_mmr_pending);
 296 }
 297
 298 static inline void uv_local_mmr_clear_nmi(void)
 299 {
 300         uv_write_local_mmr(nmi_mmr_clear, nmi_mmr_pending);
 301 }
 302
 303 /*
 304  * UV hubless NMI handler functions
 305  */
 306 static inline void uv_reassert_nmi(void)
 307 {
 308         /* (from arch/x86/include/asm/mach_traps.h) */
 309         outb(0x8f, NMI_CONTROL_PORT);
 310         inb(NMI_DUMMY_PORT);            /* dummy read */
 311         outb(0x0f, NMI_CONTROL_PORT);
 312         inb(NMI_DUMMY_PORT);            /* dummy read */
 313 }
 314
 315 static void uv_init_hubless_pch_io(int offset, int mask, int data)
 316 {
 317         int *addr = PCH_PCR_GPIO_ADDRESS(offset);
 318         int readd = readl(addr);
 319
 320         if (mask) {                     /* OR in new data */
 321                 int writed = (readd & ~mask) | data;
 322
 323                 nmi_debug("UV:PCH: %p = %x & %x | %x (%x)\n",
 324                         addr, readd, ~mask, data, writed);
 325                 writel(writed, addr);
 326         } else if (readd & data) {      /* clear status bit */
 327                 nmi_debug("UV:PCH: %p = %x\n", addr, data);
 328                 writel(data, addr);
 329         }
 330
 331         (void)readl(addr);              /* flush write data */
 332 }
 333
 334 static void uv_nmi_setup_hubless_intr(void)
 335 {
 336         uv_pch_intr_now_enabled = uv_pch_intr_enable;
 337
 338         uv_init_hubless_pch_io(
 339                 PAD_CFG_DW0_GPP_D_0, GPIROUTNMI,
 340                 uv_pch_intr_now_enabled ? GPIROUTNMI : 0);
 341
 342         nmi_debug("UV:NMI: GPP_D_0 interrupt %s\n",
 343                 uv_pch_intr_now_enabled ? "enabled" : "disabled");
 344 }
 345
 346 static struct init_nmi {
 347         unsigned int    offset;
 348         unsigned int    mask;
 349         unsigned int    data;
 350 } init_nmi[] = {
 351         {       /* HOSTSW_OWN_GPP_D_0 */
 352         .offset = 0x84,
 353         .mask = 0x1,
 354         .data = 0x0,    /* ACPI Mode */
 355         },
 356
 357 /* Clear status: */
 358         {       /* GPI_INT_STS_GPP_D_0 */
 359         .offset = 0x104,
 360         .mask = 0x0,
 361         .data = 0x1,    /* Clear Status */
 362         },
 363         {       /* GPI_GPE_STS_GPP_D_0 */
 364         .offset = 0x124,
 365         .mask = 0x0,
 366         .data = 0x1,    /* Clear Status */
 367         },
 368         {       /* GPI_SMI_STS_GPP_D_0 */
 369         .offset = 0x144,
 370         .mask = 0x0,
 371         .data = 0x1,    /* Clear Status */
 372         },
 373         {       /* GPI_NMI_STS_GPP_D_0 */
 374         .offset = 0x164,
 375         .mask = 0x0,
 376         .data = 0x1,    /* Clear Status */
 377         },
 378
 379 /* Disable interrupts: */
 380         {       /* GPI_INT_EN_GPP_D_0 */
 381         .offset = 0x114,
 382         .mask = 0x1,
 383         .data = 0x0,    /* Disable interrupt generation */
 384         },
 385         {       /* GPI_GPE_EN_GPP_D_0 */
 386         .offset = 0x134,
 387         .mask = 0x1,
 388         .data = 0x0,    /* Disable interrupt generation */
 389         },
 390         {       /* GPI_SMI_EN_GPP_D_0 */
 391         .offset = 0x154,
 392         .mask = 0x1,
 393         .data = 0x0,    /* Disable interrupt generation */
 394         },
 395         {       /* GPI_NMI_EN_GPP_D_0 */
 396         .offset = 0x174,
 397         .mask = 0x1,
 398         .data = 0x0,    /* Disable interrupt generation */
 399         },
 400
 401 /* Setup GPP_D_0 Pad Config: */
 402         {       /* PAD_CFG_DW0_GPP_D_0 */
 403         .offset = 0x4c0,
 404         .mask = 0xffffffff,
 405         .data = 0x82020100,
 406 /*
 407  *  31:30 Pad Reset Config (PADRSTCFG): = 2h  # PLTRST# (default)
 408  *
 409  *  29    RX Pad State Select (RXPADSTSEL): = 0 # Raw RX pad state directly
 410  *                                                from RX buffer (default)
 411  *
 412  *  28    RX Raw Override to '1' (RXRAW1): = 0 # No Override
 413  *
 414  *  26:25 RX Level/Edge Configuration (RXEVCFG):
 415  *      = 0h # Level
 416  *      = 1h # Edge
 417  *
 418  *  23    RX Invert (RXINV): = 0 # No Inversion (signal active high)
 419  *
 420  *  20    GPIO Input Route IOxAPIC (GPIROUTIOXAPIC):
 421  * = 0 # Routing does not cause peripheral IRQ...
 422  *     # (we want an NMI not an IRQ)
 423  *
 424  *  19    GPIO Input Route SCI (GPIROUTSCI): = 0 # Routing does not cause SCI.
 425  *  18    GPIO Input Route SMI (GPIROUTSMI): = 0 # Routing does not cause SMI.
 426  *  17    GPIO Input Route NMI (GPIROUTNMI): = 1 # Routing can cause NMI.
 427  *
 428  *  11:10 Pad Mode (PMODE1/0): = 0h = GPIO control the Pad.
 429  *   9    GPIO RX Disable (GPIORXDIS):
 430  * = 0 # Enable the input buffer (active low enable)
 431  *
 432  *   8    GPIO TX Disable (GPIOTXDIS):
 433  * = 1 # Disable the output buffer; i.e. Hi-Z
 434  *
 435  *   1 GPIO RX State (GPIORXSTATE): This is the current internal RX pad state..
 436  *   0 GPIO TX State (GPIOTXSTATE):
 437  * = 0 # (Leave at default)
 438  */
 439         },
 440
 441 /* Pad Config DW1 */
 442         {       /* PAD_CFG_DW1_GPP_D_0 */
 443         .offset = 0x4c4,
 444         .mask = 0x3c00,
 445         .data = 0,      /* Termination = none (default) */
 446         },
 447 };
 448
 449 static void uv_init_hubless_pch_d0(void)
 450 {
 451         int i, read;
 452
 453         read = *PCH_PCR_GPIO_ADDRESS(PAD_OWN_GPP_D_0);
 454         if (read != 0) {
 455                 pr_info("UV: Hubless NMI already configured\n");
 456                 return;
 457         }
 458
 459         nmi_debug("UV: Initializing UV Hubless NMI on PCH\n");
 460         for (i = 0; i < ARRAY_SIZE(init_nmi); i++) {
 461                 uv_init_hubless_pch_io(init_nmi[i].offset,
 462                                         init_nmi[i].mask,
 463                                         init_nmi[i].data);
 464         }
 465 }
 466
 467 static int uv_nmi_test_hubless(struct uv_hub_nmi_s *hub_nmi)
 468 {
 469         int *pstat = PCH_PCR_GPIO_ADDRESS(GPI_NMI_STS_GPP_D_0);
 470         int status = *pstat;
 471
 472         hub_nmi->nmi_value = status;
 473         atomic_inc(&hub_nmi->read_mmr_count);
 474
 475         if (!(status & STS_GPP_D_0_MASK))       /* Not a UV external NMI */
 476                 return 0;
 477
 478         *pstat = STS_GPP_D_0_MASK;      /* Is a UV NMI: clear GPP_D_0 status */
 479         (void)*pstat;                   /* Flush write */
 480
 481         return 1;
 482 }
 483
 484 static int uv_test_nmi(struct uv_hub_nmi_s *hub_nmi)
 485 {
 486         if (hub_nmi->hub_present)
 487                 return uv_nmi_test_mmr(hub_nmi);
 488
 489         if (hub_nmi->pch_owner)         /* Only PCH owner can check status */
 490                 return uv_nmi_test_hubless(hub_nmi);
 491
 492         return -1;
 493 }
 494
 495 /*
 496  * If first CPU in on this hub, set hub_nmi "in_nmi" and "owner" values and
 497  * return true.  If first CPU in on the system, set global "in_nmi" flag.
 498  */
 499 static int uv_set_in_nmi(int cpu, struct uv_hub_nmi_s *hub_nmi)
 500 {
 501         int first = atomic_add_unless(&hub_nmi->in_nmi, 1, 1);
 502
 503         if (first) {
 504                 atomic_set(&hub_nmi->cpu_owner, cpu);
 505                 if (atomic_add_unless(&uv_in_nmi, 1, 1))
 506                         atomic_set(&uv_nmi_cpu, cpu);
 507
 508                 atomic_inc(&hub_nmi->nmi_count);
 509         }
 510         return first;
 511 }
 512
 513 /* Check if this is a system NMI event */
 514 static int uv_check_nmi(struct uv_hub_nmi_s *hub_nmi)
 515 {
 516         int cpu = smp_processor_id();
 517         int nmi = 0;
 518         int nmi_detected = 0;
 519
 520         local64_inc(&uv_nmi_count);
 521         this_cpu_inc(uv_cpu_nmi.queries);
 522
 523         do {
 524                 nmi = atomic_read(&hub_nmi->in_nmi);
 525                 if (nmi)
 526                         break;
 527
 528                 if (raw_spin_trylock(&hub_nmi->nmi_lock)) {
 529                         nmi_detected = uv_test_nmi(hub_nmi);
 530
 531                         /* Check flag for UV external NMI */
 532                         if (nmi_detected > 0) {
 533                                 uv_set_in_nmi(cpu, hub_nmi);
 534                                 nmi = 1;
 535                                 break;
 536                         }
 537
 538                         /* A non-PCH node in a hubless system waits for NMI */
 539                         else if (nmi_detected < 0)
 540                                 goto slave_wait;
 541
 542                         /* MMR/PCH NMI flag is clear */
 543                         raw_spin_unlock(&hub_nmi->nmi_lock);
 544
 545                 } else {
 546
 547                         /* Wait a moment for the HUB NMI locker to set flag */
 548 slave_wait:             cpu_relax();
 549                         udelay(uv_nmi_slave_delay);
 550
 551                         /* Re-check hub in_nmi flag */
 552                         nmi = atomic_read(&hub_nmi->in_nmi);
 553                         if (nmi)
 554                                 break;
 555                 }
 556
 557                 /*
 558                  * Check if this BMC missed setting the MMR NMI flag (or)
 559                  * UV hubless system where only PCH owner can check flag
 560                  */
 561                 if (!nmi) {
 562                         nmi = atomic_read(&uv_in_nmi);
 563                         if (nmi)
 564                                 uv_set_in_nmi(cpu, hub_nmi);
 565                 }
 566
 567                 /* If we're holding the hub lock, release it now */
 568                 if (nmi_detected < 0)
 569                         raw_spin_unlock(&hub_nmi->nmi_lock);
 570
 571         } while (0);
 572
 573         if (!nmi)
 574                 local64_inc(&uv_nmi_misses);
 575
 576         return nmi;
 577 }
 578
 579 /* Need to reset the NMI MMR register, but only once per hub. */
 580 static inline void uv_clear_nmi(int cpu)
 581 {
 582         struct uv_hub_nmi_s *hub_nmi = uv_hub_nmi;
 583
 584         if (cpu == atomic_read(&hub_nmi->cpu_owner)) {
 585                 atomic_set(&hub_nmi->cpu_owner, -1);
 586                 atomic_set(&hub_nmi->in_nmi, 0);
 587                 if (hub_nmi->hub_present)
 588                         uv_local_mmr_clear_nmi();
 589                 else
 590                         uv_reassert_nmi();
 591                 raw_spin_unlock(&hub_nmi->nmi_lock);
 592         }
 593 }
 594
 595 /* Ping non-responding CPU's attempting to force them into the NMI handler */
 596 static void uv_nmi_nr_cpus_ping(void)
 597 {
 598         int cpu;
 599
 600         for_each_cpu(cpu, uv_nmi_cpu_mask)
 601                 uv_cpu_nmi_per(cpu).pinging = 1;
 602
 603         apic->send_IPI_mask(uv_nmi_cpu_mask, APIC_DM_NMI);
 604 }
 605
 606 /* Clean up flags for CPU's that ignored both NMI and ping */
 607 static void uv_nmi_cleanup_mask(void)
 608 {
 609         int cpu;
 610
 611         for_each_cpu(cpu, uv_nmi_cpu_mask) {
 612                 uv_cpu_nmi_per(cpu).pinging =  0;
 613                 uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_OUT;
 614                 cpumask_clear_cpu(cpu, uv_nmi_cpu_mask);
 615         }
 616 }
 617
 618 /* Loop waiting as CPU's enter NMI handler */
 619 static int uv_nmi_wait_cpus(int first)
 620 {
 621         int i, j, k, n = num_online_cpus();
 622         int last_k = 0, waiting = 0;
 623         int cpu = smp_processor_id();
 624
 625         if (first) {
 626                 cpumask_copy(uv_nmi_cpu_mask, cpu_online_mask);
 627                 k = 0;
 628         } else {
 629                 k = n - cpumask_weight(uv_nmi_cpu_mask);
 630         }
 631
 632         /* PCH NMI causes only one CPU to respond */
 633         if (first && uv_pch_intr_now_enabled) {
 634                 cpumask_clear_cpu(cpu, uv_nmi_cpu_mask);
 635                 return n - k - 1;
 636         }
 637
 638         udelay(uv_nmi_initial_delay);
 639         for (i = 0; i < uv_nmi_retry_count; i++) {
 640                 int loop_delay = uv_nmi_loop_delay;
 641
 642                 for_each_cpu(j, uv_nmi_cpu_mask) {
 643                         if (uv_cpu_nmi_per(j).state) {
 644                                 cpumask_clear_cpu(j, uv_nmi_cpu_mask);
 645                                 if (++k >= n)
 646                                         break;
 647                         }
 648                 }
 649                 if (k >= n) {           /* all in? */
 650                         k = n;
 651                         break;
 652                 }
 653                 if (last_k != k) {      /* abort if no new CPU's coming in */
 654                         last_k = k;
 655                         waiting = 0;
 656                 } else if (++waiting > uv_nmi_wait_count)
 657                         break;
 658
 659                 /* Extend delay if waiting only for CPU 0: */
 660                 if (waiting && (n - k) == 1 &&
 661                     cpumask_test_cpu(0, uv_nmi_cpu_mask))
 662                         loop_delay *= 100;
 663
 664                 udelay(loop_delay);
 665         }
 666         atomic_set(&uv_nmi_cpus_in_nmi, k);
 667         return n - k;
 668 }
 669
 670 /* Wait until all slave CPU's have entered UV NMI handler */
 671 static void uv_nmi_wait(int master)
 672 {
 673         /* Indicate this CPU is in: */
 674         this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_IN);
 675
 676         /* If not the first CPU in (the master), then we are a slave CPU */
 677         if (!master)
 678                 return;
 679
 680         do {
 681                 /* Wait for all other CPU's to gather here */
 682                 if (!uv_nmi_wait_cpus(1))
 683                         break;
 684
 685                 /* If not all made it in, send IPI NMI to them */
 686                 pr_alert("UV: Sending NMI IPI to %d CPUs: %*pbl\n",
 687                          cpumask_weight(uv_nmi_cpu_mask),
 688                          cpumask_pr_args(uv_nmi_cpu_mask));
 689
 690                 uv_nmi_nr_cpus_ping();
 691
 692                 /* If all CPU's are in, then done */
 693                 if (!uv_nmi_wait_cpus(0))
 694                         break;
 695
 696                 pr_alert("UV: %d CPUs not in NMI loop: %*pbl\n",
 697                          cpumask_weight(uv_nmi_cpu_mask),
 698                          cpumask_pr_args(uv_nmi_cpu_mask));
 699         } while (0);
 700
 701         pr_alert("UV: %d of %d CPUs in NMI\n",
 702                 atomic_read(&uv_nmi_cpus_in_nmi), num_online_cpus());
 703 }
 704
 705 /* Dump Instruction Pointer header */
 706 static void uv_nmi_dump_cpu_ip_hdr(void)
 707 {
 708         pr_info("\nUV: %4s %6s %-32s %s   (Note: PID 0 not listed)\n",
 709                 "CPU", "PID", "COMMAND", "IP");
 710 }
 711
 712 /* Dump Instruction Pointer info */
 713 static void uv_nmi_dump_cpu_ip(int cpu, struct pt_regs *regs)
 714 {
 715         pr_info("UV: %4d %6d %-32.32s %pS",
 716                 cpu, current->pid, current->comm, (void *)regs->ip);
 717 }
 718
 719 /*
 720  * Dump this CPU's state.  If action was set to "kdump" and the crash_kexec
 721  * failed, then we provide "dump" as an alternate action.  Action "dump" now
 722  * also includes the show "ips" (instruction pointers) action whereas the
 723  * action "ips" only displays instruction pointers for the non-idle CPU's.
 724  * This is an abbreviated form of the "ps" command.
 725  */
 726 static void uv_nmi_dump_state_cpu(int cpu, struct pt_regs *regs)
 727 {
 728         const char *dots = " ................................. ";
 729
 730         if (cpu == 0)
 731                 uv_nmi_dump_cpu_ip_hdr();
 732
 733         if (current->pid != 0 || !uv_nmi_action_is("ips"))
 734                 uv_nmi_dump_cpu_ip(cpu, regs);
 735
 736         if (uv_nmi_action_is("dump")) {
 737                 pr_info("UV:%sNMI process trace for CPU %d\n", dots, cpu);
 738                 show_regs(regs);
 739         }
 740
 741         this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_DUMP_DONE);
 742 }
 743
 744 /* Trigger a slave CPU to dump it's state */
 745 static void uv_nmi_trigger_dump(int cpu)
 746 {
 747         int retry = uv_nmi_trigger_delay;
 748
 749         if (uv_cpu_nmi_per(cpu).state != UV_NMI_STATE_IN)
 750                 return;
 751
 752         uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_DUMP;
 753         do {
 754                 cpu_relax();
 755                 udelay(10);
 756                 if (uv_cpu_nmi_per(cpu).state
 757                                 != UV_NMI_STATE_DUMP)
 758                         return;
 759         } while (--retry > 0);
 760
 761         pr_crit("UV: CPU %d stuck in process dump function\n", cpu);
 762         uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_DUMP_DONE;
 763 }
 764
 765 /* Wait until all CPU's ready to exit */
 766 static void uv_nmi_sync_exit(int master)
 767 {
 768         atomic_dec(&uv_nmi_cpus_in_nmi);
 769         if (master) {
 770                 while (atomic_read(&uv_nmi_cpus_in_nmi) > 0)
 771                         cpu_relax();
 772                 atomic_set(&uv_nmi_slave_continue, SLAVE_CLEAR);
 773         } else {
 774                 while (atomic_read(&uv_nmi_slave_continue))
 775                         cpu_relax();
 776         }
 777 }
 778
 779 /* Current "health" check is to check which CPU's are responsive */
 780 static void uv_nmi_action_health(int cpu, struct pt_regs *regs, int master)
 781 {
 782         if (master) {
 783                 int in = atomic_read(&uv_nmi_cpus_in_nmi);
 784                 int out = num_online_cpus() - in;
 785
 786                 pr_alert("UV: NMI CPU health check (non-responding:%d)\n", out);
 787                 atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT);
 788         } else {
 789                 while (!atomic_read(&uv_nmi_slave_continue))
 790                         cpu_relax();
 791         }
 792         uv_nmi_sync_exit(master);
 793 }
 794
 795 /* Walk through CPU list and dump state of each */
 796 static void uv_nmi_dump_state(int cpu, struct pt_regs *regs, int master)
 797 {
 798         if (master) {
 799                 int tcpu;
 800                 int ignored = 0;
 801                 int saved_console_loglevel = console_loglevel;
 802
 803                 pr_alert("UV: tracing %s for %d CPUs from CPU %d\n",
 804                         uv_nmi_action_is("ips") ? "IPs" : "processes",
 805                         atomic_read(&uv_nmi_cpus_in_nmi), cpu);
 806
 807                 console_loglevel = uv_nmi_loglevel;
 808                 atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT);
 809                 for_each_online_cpu(tcpu) {
 810                         if (cpumask_test_cpu(tcpu, uv_nmi_cpu_mask))
 811                                 ignored++;
 812                         else if (tcpu == cpu)
 813                                 uv_nmi_dump_state_cpu(tcpu, regs);
 814                         else
 815                                 uv_nmi_trigger_dump(tcpu);
 816                 }
 817                 if (ignored)
 818                         pr_alert("UV: %d CPUs ignored NMI\n", ignored);
 819
 820                 console_loglevel = saved_console_loglevel;
 821                 pr_alert("UV: process trace complete\n");
 822         } else {
 823                 while (!atomic_read(&uv_nmi_slave_continue))
 824                         cpu_relax();
 825                 while (this_cpu_read(uv_cpu_nmi.state) != UV_NMI_STATE_DUMP)
 826                         cpu_relax();
 827                 uv_nmi_dump_state_cpu(cpu, regs);
 828         }
 829         uv_nmi_sync_exit(master);
 830 }
 831
 832 static void uv_nmi_touch_watchdogs(void)
 833 {
 834         touch_softlockup_watchdog_sync();
 835         clocksource_touch_watchdog();
 836         rcu_cpu_stall_reset();
 837         touch_nmi_watchdog();
 838 }
 839
 840 static void uv_nmi_kdump(int cpu, int main, struct pt_regs *regs)
 841 {
 842         /* Check if kdump kernel loaded for both main and secondary CPUs */
 843         if (!kexec_crash_image) {
 844                 if (main)
 845                         pr_err("UV: NMI error: kdump kernel not loaded\n");
 846                 return;
 847         }
 848
 849         /* Call crash to dump system state */
 850         if (main) {
 851                 pr_emerg("UV: NMI executing crash_kexec on CPU%d\n", cpu);
 852                 crash_kexec(regs);
 853
 854                 pr_emerg("UV: crash_kexec unexpectedly returned\n");
 855                 atomic_set(&uv_nmi_kexec_failed, 1);
 856
 857         } else { /* secondary */
 858
 859                 /* If kdump kernel fails, secondaries will exit this loop */
 860                 while (atomic_read(&uv_nmi_kexec_failed) == 0) {
 861
 862                         /* Once shootdown cpus starts, they do not return */
 863                         run_crash_ipi_callback(regs);
 864
 865                         mdelay(10);
 866                 }
 867         }
 868 }
 869
 870 #ifdef CONFIG_KGDB
 871 #ifdef CONFIG_KGDB_KDB
 872 static inline int uv_nmi_kdb_reason(void)
 873 {
 874         return KDB_REASON_SYSTEM_NMI;
 875 }
 876 #else /* !CONFIG_KGDB_KDB */
 877 static inline int uv_nmi_kdb_reason(void)
 878 {
 879         /* Ensure user is expecting to attach gdb remote */
 880         if (uv_nmi_action_is("kgdb"))
 881                 return 0;
 882
 883         pr_err("UV: NMI error: KDB is not enabled in this kernel\n");
 884         return -1;
 885 }
 886 #endif /* CONFIG_KGDB_KDB */
 887
 888 /*
 889  * Call KGDB/KDB from NMI handler
 890  *
 891  * Note that if both KGDB and KDB are configured, then the action of 'kgdb' or
 892  * 'kdb' has no affect on which is used.  See the KGDB documentation for further
 893  * information.
 894  */
 895 static void uv_call_kgdb_kdb(int cpu, struct pt_regs *regs, int master)
 896 {
 897         if (master) {
 898                 int reason = uv_nmi_kdb_reason();
 899                 int ret;
 900
 901                 if (reason < 0)
 902                         return;
 903
 904                 /* Call KGDB NMI handler as MASTER */
 905                 ret = kgdb_nmicallin(cpu, X86_TRAP_NMI, regs, reason,
 906                                 &uv_nmi_slave_continue);
 907                 if (ret) {
 908                         pr_alert("KGDB returned error, is kgdboc set?\n");
 909                         atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT);
 910                 }
 911         } else {
 912                 /* Wait for KGDB signal that it's ready for slaves to enter */
 913                 int sig;
 914
 915                 do {
 916                         cpu_relax();
 917                         sig = atomic_read(&uv_nmi_slave_continue);
 918                 } while (!sig);
 919
 920                 /* Call KGDB as slave */
 921                 if (sig == SLAVE_CONTINUE)
 922                         kgdb_nmicallback(cpu, regs);
 923         }
 924         uv_nmi_sync_exit(master);
 925 }
 926
 927 #else /* !CONFIG_KGDB */
 928 static inline void uv_call_kgdb_kdb(int cpu, struct pt_regs *regs, int master)
 929 {
 930         pr_err("UV: NMI error: KGDB is not enabled in this kernel\n");
 931 }
 932 #endif /* !CONFIG_KGDB */
 933
 934 /*
 935  * UV NMI handler
 936  */
 937 static int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
 938 {
 939         struct uv_hub_nmi_s *hub_nmi = uv_hub_nmi;
 940         int cpu = smp_processor_id();
 941         int master = 0;
 942         unsigned long flags;
 943
 944         local_irq_save(flags);
 945
 946         /* If not a UV System NMI, ignore */
 947         if (!this_cpu_read(uv_cpu_nmi.pinging) && !uv_check_nmi(hub_nmi)) {
 948                 local_irq_restore(flags);
 949                 return NMI_DONE;
 950         }
 951
 952         /* Indicate we are the first CPU into the NMI handler */
 953         master = (atomic_read(&uv_nmi_cpu) == cpu);
 954
 955         /* If NMI action is "kdump", then attempt to do it */
 956         if (uv_nmi_action_is("kdump")) {
 957                 uv_nmi_kdump(cpu, master, regs);
 958
 959                 /* Unexpected return, revert action to "dump" */
 960                 if (master)
 961                         strncpy(uv_nmi_action, "dump", strlen(uv_nmi_action));
 962         }
 963
 964         /* Pause as all CPU's enter the NMI handler */
 965         uv_nmi_wait(master);
 966
 967         /* Process actions other than "kdump": */
 968         if (uv_nmi_action_is("health")) {
 969                 uv_nmi_action_health(cpu, regs, master);
 970         } else if (uv_nmi_action_is("ips") || uv_nmi_action_is("dump")) {
 971                 uv_nmi_dump_state(cpu, regs, master);
 972         } else if (uv_nmi_action_is("kdb") || uv_nmi_action_is("kgdb")) {
 973                 uv_call_kgdb_kdb(cpu, regs, master);
 974         } else {
 975                 if (master)
 976                         pr_alert("UV: unknown NMI action: %s\n", uv_nmi_action);
 977                 uv_nmi_sync_exit(master);
 978         }
 979
 980         /* Clear per_cpu "in_nmi" flag */
 981         this_cpu_write(uv_cpu_nmi.state, UV_NMI_STATE_OUT);
 982
 983         /* Clear MMR NMI flag on each hub */
 984         uv_clear_nmi(cpu);
 985
 986         /* Clear global flags */
 987         if (master) {
 988                 if (cpumask_weight(uv_nmi_cpu_mask))
 989                         uv_nmi_cleanup_mask();
 990                 atomic_set(&uv_nmi_cpus_in_nmi, -1);
 991                 atomic_set(&uv_nmi_cpu, -1);
 992                 atomic_set(&uv_in_nmi, 0);
 993                 atomic_set(&uv_nmi_kexec_failed, 0);
 994                 atomic_set(&uv_nmi_slave_continue, SLAVE_CLEAR);
 995         }
 996
 997         uv_nmi_touch_watchdogs();
 998         local_irq_restore(flags);
 999
1000         return NMI_HANDLED;
1001 }
1002
1003 /*
1004  * NMI handler for pulling in CPU's when perf events are grabbing our NMI
1005  */
1006 static int uv_handle_nmi_ping(unsigned int reason, struct pt_regs *regs)
1007 {
1008         int ret;
1009
1010         this_cpu_inc(uv_cpu_nmi.queries);
1011         if (!this_cpu_read(uv_cpu_nmi.pinging)) {
1012                 local64_inc(&uv_nmi_ping_misses);
1013                 return NMI_DONE;
1014         }
1015
1016         this_cpu_inc(uv_cpu_nmi.pings);
1017         local64_inc(&uv_nmi_ping_count);
1018         ret = uv_handle_nmi(reason, regs);
1019         this_cpu_write(uv_cpu_nmi.pinging, 0);
1020         return ret;
1021 }
1022
1023 static void uv_register_nmi_notifier(void)
1024 {
1025         if (register_nmi_handler(NMI_UNKNOWN, uv_handle_nmi, 0, "uv"))
1026                 pr_warn("UV: NMI handler failed to register\n");
1027
1028         if (register_nmi_handler(NMI_LOCAL, uv_handle_nmi_ping, 0, "uvping"))
1029                 pr_warn("UV: PING NMI handler failed to register\n");
1030 }
1031
1032 void uv_nmi_init(void)
1033 {
1034         unsigned int value;
1035
1036         /*
1037          * Unmask NMI on all CPU's
1038          */
1039         value = apic_read(APIC_LVT1) | APIC_DM_NMI;
1040         value &= ~APIC_LVT_MASKED;
1041         apic_write(APIC_LVT1, value);
1042 }
1043
1044 /* Setup HUB NMI info */
1045 static void __init uv_nmi_setup_common(bool hubbed)
1046 {
1047         int size = sizeof(void *) * (1 << NODES_SHIFT);
1048         int cpu;
1049
1050         uv_hub_nmi_list = kzalloc(size, GFP_KERNEL);
1051         nmi_debug("UV: NMI hub list @ 0x%p (%d)\n", uv_hub_nmi_list, size);
1052         BUG_ON(!uv_hub_nmi_list);
1053         size = sizeof(struct uv_hub_nmi_s);
1054         for_each_present_cpu(cpu) {
1055                 int nid = cpu_to_node(cpu);
1056                 if (uv_hub_nmi_list[nid] == NULL) {
1057                         uv_hub_nmi_list[nid] = kzalloc_node(size,
1058                                                             GFP_KERNEL, nid);
1059                         BUG_ON(!uv_hub_nmi_list[nid]);
1060                         raw_spin_lock_init(&(uv_hub_nmi_list[nid]->nmi_lock));
1061                         atomic_set(&uv_hub_nmi_list[nid]->cpu_owner, -1);
1062                         uv_hub_nmi_list[nid]->hub_present = hubbed;
1063                         uv_hub_nmi_list[nid]->pch_owner = (nid == 0);
1064                 }
1065                 uv_hub_nmi_per(cpu) = uv_hub_nmi_list[nid];
1066         }
1067         BUG_ON(!alloc_cpumask_var(&uv_nmi_cpu_mask, GFP_KERNEL));
1068 }
1069
1070 /* Setup for UV Hub systems */
1071 void __init uv_nmi_setup(void)
1072 {
1073         uv_nmi_setup_mmrs();
1074         uv_nmi_setup_common(true);
1075         uv_register_nmi_notifier();
1076         pr_info("UV: Hub NMI enabled\n");
1077 }
1078
1079 /* Setup for UV Hubless systems */
1080 void __init uv_nmi_setup_hubless(void)
1081 {
1082         uv_nmi_setup_common(false);
1083         pch_base = xlate_dev_mem_ptr(PCH_PCR_GPIO_1_BASE);
1084         nmi_debug("UV: PCH base:%p from 0x%lx, GPP_D_0\n",
1085                 pch_base, PCH_PCR_GPIO_1_BASE);
1086         if (uv_pch_init_enable)
1087                 uv_init_hubless_pch_d0();
1088         uv_init_hubless_pch_io(GPI_NMI_ENA_GPP_D_0,
1089                                 STS_GPP_D_0_MASK, STS_GPP_D_0_MASK);
1090         uv_nmi_setup_hubless_intr();
1091         /* Ensure NMI enabled in Processor Interface Reg: */
1092         uv_reassert_nmi();
1093         uv_register_nmi_notifier();
1094         pr_info("UV: PCH NMI enabled\n");
1095 }