1 /* 2 * Copyright 2014 IBM Corp. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 */ 9 10 #include <linux/interrupt.h> 11 #include <linux/workqueue.h> 12 #include <linux/sched.h> 13 #include <linux/wait.h> 14 #include <linux/slab.h> 15 #include <linux/pid.h> 16 #include <asm/cputable.h> 17 #include <misc/cxl-base.h> 18 19 #include "cxl.h" 20 #include "trace.h" 21 22 static int afu_irq_range_start(void) 23 { 24 if (cpu_has_feature(CPU_FTR_HVMODE)) 25 return 1; 26 return 0; 27 } 28 29 static irqreturn_t schedule_cxl_fault(struct cxl_context *ctx, u64 dsisr, u64 dar) 30 { 31 ctx->dsisr = dsisr; 32 ctx->dar = dar; 33 schedule_work(&ctx->fault_work); 34 return IRQ_HANDLED; 35 } 36 37 irqreturn_t cxl_irq(int irq, struct cxl_context *ctx, struct cxl_irq_info *irq_info) 38 { 39 u64 dsisr, dar; 40 41 dsisr = irq_info->dsisr; 42 dar = irq_info->dar; 43 44 trace_cxl_psl_irq(ctx, irq, dsisr, dar); 45 46 pr_devel("CXL interrupt %i for afu pe: %i DSISR: %#llx DAR: %#llx\n", irq, ctx->pe, dsisr, dar); 47 48 if (dsisr & CXL_PSL_DSISR_An_DS) { 49 /* 50 * We don't inherently need to sleep to handle this, but we do 51 * need to get a ref to the task's mm, which we can't do from 52 * irq context without the potential for a deadlock since it 53 * takes the task_lock. An alternate option would be to keep a 54 * reference to the task's mm the entire time it has cxl open, 55 * but to do that we need to solve the issue where we hold a 56 * ref to the mm, but the mm can hold a ref to the fd after an 57 * mmap preventing anything from being cleaned up. 58 */ 59 pr_devel("Scheduling segment miss handling for later pe: %i\n", ctx->pe); 60 return schedule_cxl_fault(ctx, dsisr, dar); 61 } 62 63 if (dsisr & CXL_PSL_DSISR_An_M) 64 pr_devel("CXL interrupt: PTE not found\n"); 65 if (dsisr & CXL_PSL_DSISR_An_P) 66 pr_devel("CXL interrupt: Storage protection violation\n"); 67 if (dsisr & CXL_PSL_DSISR_An_A) 68 pr_devel("CXL interrupt: AFU lock access to write through or cache inhibited storage\n"); 69 if (dsisr & CXL_PSL_DSISR_An_S) 70 pr_devel("CXL interrupt: Access was afu_wr or afu_zero\n"); 71 if (dsisr & CXL_PSL_DSISR_An_K) 72 pr_devel("CXL interrupt: Access not permitted by virtual page class key protection\n"); 73 74 if (dsisr & CXL_PSL_DSISR_An_DM) { 75 /* 76 * In some cases we might be able to handle the fault 77 * immediately if hash_page would succeed, but we still need 78 * the task's mm, which as above we can't get without a lock 79 */ 80 pr_devel("Scheduling page fault handling for later pe: %i\n", ctx->pe); 81 return schedule_cxl_fault(ctx, dsisr, dar); 82 } 83 if (dsisr & CXL_PSL_DSISR_An_ST) 84 WARN(1, "CXL interrupt: Segment Table PTE not found\n"); 85 if (dsisr & CXL_PSL_DSISR_An_UR) 86 pr_devel("CXL interrupt: AURP PTE not found\n"); 87 if (dsisr & CXL_PSL_DSISR_An_PE) 88 return cxl_ops->handle_psl_slice_error(ctx, dsisr, 89 irq_info->errstat); 90 if (dsisr & CXL_PSL_DSISR_An_AE) { 91 pr_devel("CXL interrupt: AFU Error 0x%016llx\n", irq_info->afu_err); 92 93 if (ctx->pending_afu_err) { 94 /* 95 * This shouldn't happen - the PSL treats these errors 96 * as fatal and will have reset the AFU, so there's not 97 * much point buffering multiple AFU errors. 98 * OTOH if we DO ever see a storm of these come in it's 99 * probably best that we log them somewhere: 100 */ 101 dev_err_ratelimited(&ctx->afu->dev, "CXL AFU Error " 102 "undelivered to pe %i: 0x%016llx\n", 103 ctx->pe, irq_info->afu_err); 104 } else { 105 spin_lock(&ctx->lock); 106 ctx->afu_err = irq_info->afu_err; 107 ctx->pending_afu_err = 1; 108 spin_unlock(&ctx->lock); 109 110 wake_up_all(&ctx->wq); 111 } 112 113 cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_A, 0); 114 return IRQ_HANDLED; 115 } 116 if (dsisr & CXL_PSL_DSISR_An_OC) 117 pr_devel("CXL interrupt: OS Context Warning\n"); 118 119 WARN(1, "Unhandled CXL PSL IRQ\n"); 120 return IRQ_HANDLED; 121 } 122 123 static irqreturn_t cxl_irq_afu(int irq, void *data) 124 { 125 struct cxl_context *ctx = data; 126 irq_hw_number_t hwirq = irqd_to_hwirq(irq_get_irq_data(irq)); 127 int irq_off, afu_irq = 0; 128 __u16 range; 129 int r; 130 131 /* 132 * Look for the interrupt number. 133 * On bare-metal, we know range 0 only contains the PSL 134 * interrupt so we could start counting at range 1 and initialize 135 * afu_irq at 1. 136 * In a guest, range 0 also contains AFU interrupts, so it must 137 * be counted for. Therefore we initialize afu_irq at 0 to take into 138 * account the PSL interrupt. 139 * 140 * For code-readability, it just seems easier to go over all 141 * the ranges on bare-metal and guest. The end result is the same. 142 */ 143 for (r = 0; r < CXL_IRQ_RANGES; r++) { 144 irq_off = hwirq - ctx->irqs.offset[r]; 145 range = ctx->irqs.range[r]; 146 if (irq_off >= 0 && irq_off < range) { 147 afu_irq += irq_off; 148 break; 149 } 150 afu_irq += range; 151 } 152 if (unlikely(r >= CXL_IRQ_RANGES)) { 153 WARN(1, "Received AFU IRQ out of range for pe %i (virq %i hwirq %lx)\n", 154 ctx->pe, irq, hwirq); 155 return IRQ_HANDLED; 156 } 157 158 trace_cxl_afu_irq(ctx, afu_irq, irq, hwirq); 159 pr_devel("Received AFU interrupt %i for pe: %i (virq %i hwirq %lx)\n", 160 afu_irq, ctx->pe, irq, hwirq); 161 162 if (unlikely(!ctx->irq_bitmap)) { 163 WARN(1, "Received AFU IRQ for context with no IRQ bitmap\n"); 164 return IRQ_HANDLED; 165 } 166 spin_lock(&ctx->lock); 167 set_bit(afu_irq - 1, ctx->irq_bitmap); 168 ctx->pending_irq = true; 169 spin_unlock(&ctx->lock); 170 171 wake_up_all(&ctx->wq); 172 173 return IRQ_HANDLED; 174 } 175 176 unsigned int cxl_map_irq(struct cxl *adapter, irq_hw_number_t hwirq, 177 irq_handler_t handler, void *cookie, const char *name) 178 { 179 unsigned int virq; 180 int result; 181 182 /* IRQ Domain? */ 183 virq = irq_create_mapping(NULL, hwirq); 184 if (!virq) { 185 dev_warn(&adapter->dev, "cxl_map_irq: irq_create_mapping failed\n"); 186 return 0; 187 } 188 189 if (cxl_ops->setup_irq) 190 cxl_ops->setup_irq(adapter, hwirq, virq); 191 192 pr_devel("hwirq %#lx mapped to virq %u\n", hwirq, virq); 193 194 result = request_irq(virq, handler, 0, name, cookie); 195 if (result) { 196 dev_warn(&adapter->dev, "cxl_map_irq: request_irq failed: %i\n", result); 197 return 0; 198 } 199 200 return virq; 201 } 202 203 void cxl_unmap_irq(unsigned int virq, void *cookie) 204 { 205 free_irq(virq, cookie); 206 } 207 208 int cxl_register_one_irq(struct cxl *adapter, 209 irq_handler_t handler, 210 void *cookie, 211 irq_hw_number_t *dest_hwirq, 212 unsigned int *dest_virq, 213 const char *name) 214 { 215 int hwirq, virq; 216 217 if ((hwirq = cxl_ops->alloc_one_irq(adapter)) < 0) 218 return hwirq; 219 220 if (!(virq = cxl_map_irq(adapter, hwirq, handler, cookie, name))) 221 goto err; 222 223 *dest_hwirq = hwirq; 224 *dest_virq = virq; 225 226 return 0; 227 228 err: 229 cxl_ops->release_one_irq(adapter, hwirq); 230 return -ENOMEM; 231 } 232 233 void afu_irq_name_free(struct cxl_context *ctx) 234 { 235 struct cxl_irq_name *irq_name, *tmp; 236 237 list_for_each_entry_safe(irq_name, tmp, &ctx->irq_names, list) { 238 kfree(irq_name->name); 239 list_del(&irq_name->list); 240 kfree(irq_name); 241 } 242 } 243 244 int afu_allocate_irqs(struct cxl_context *ctx, u32 count) 245 { 246 int rc, r, i, j = 1; 247 struct cxl_irq_name *irq_name; 248 int alloc_count; 249 250 /* 251 * In native mode, range 0 is reserved for the multiplexed 252 * PSL interrupt. It has been allocated when the AFU was initialized. 253 * 254 * In a guest, the PSL interrupt is not mutliplexed, but per-context, 255 * and is the first interrupt from range 0. It still needs to be 256 * allocated, so bump the count by one. 257 */ 258 if (cpu_has_feature(CPU_FTR_HVMODE)) 259 alloc_count = count; 260 else 261 alloc_count = count + 1; 262 263 /* Initialize the list head to hold irq names */ 264 INIT_LIST_HEAD(&ctx->irq_names); 265 266 if ((rc = cxl_ops->alloc_irq_ranges(&ctx->irqs, ctx->afu->adapter, 267 alloc_count))) 268 return rc; 269 270 if (cpu_has_feature(CPU_FTR_HVMODE)) { 271 /* Multiplexed PSL Interrupt */ 272 ctx->irqs.offset[0] = ctx->afu->native->psl_hwirq; 273 ctx->irqs.range[0] = 1; 274 } 275 276 ctx->irq_count = count; 277 ctx->irq_bitmap = kcalloc(BITS_TO_LONGS(count), 278 sizeof(*ctx->irq_bitmap), GFP_KERNEL); 279 if (!ctx->irq_bitmap) 280 goto out; 281 282 /* 283 * Allocate names first. If any fail, bail out before allocating 284 * actual hardware IRQs. 285 */ 286 for (r = afu_irq_range_start(); r < CXL_IRQ_RANGES; r++) { 287 for (i = 0; i < ctx->irqs.range[r]; i++) { 288 irq_name = kmalloc(sizeof(struct cxl_irq_name), 289 GFP_KERNEL); 290 if (!irq_name) 291 goto out; 292 irq_name->name = kasprintf(GFP_KERNEL, "cxl-%s-pe%i-%i", 293 dev_name(&ctx->afu->dev), 294 ctx->pe, j); 295 if (!irq_name->name) { 296 kfree(irq_name); 297 goto out; 298 } 299 /* Add to tail so next look get the correct order */ 300 list_add_tail(&irq_name->list, &ctx->irq_names); 301 j++; 302 } 303 } 304 return 0; 305 306 out: 307 cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter); 308 afu_irq_name_free(ctx); 309 return -ENOMEM; 310 } 311 312 static void afu_register_hwirqs(struct cxl_context *ctx) 313 { 314 irq_hw_number_t hwirq; 315 struct cxl_irq_name *irq_name; 316 int r, i; 317 irqreturn_t (*handler)(int irq, void *data); 318 319 /* We've allocated all memory now, so let's do the irq allocations */ 320 irq_name = list_first_entry(&ctx->irq_names, struct cxl_irq_name, list); 321 for (r = afu_irq_range_start(); r < CXL_IRQ_RANGES; r++) { 322 hwirq = ctx->irqs.offset[r]; 323 for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) { 324 if (r == 0 && i == 0) 325 /* 326 * The very first interrupt of range 0 is 327 * always the PSL interrupt, but we only 328 * need to connect a handler for guests, 329 * because there's one PSL interrupt per 330 * context. 331 * On bare-metal, the PSL interrupt is 332 * multiplexed and was setup when the AFU 333 * was configured. 334 */ 335 handler = cxl_ops->psl_interrupt; 336 else 337 handler = cxl_irq_afu; 338 cxl_map_irq(ctx->afu->adapter, hwirq, handler, ctx, 339 irq_name->name); 340 irq_name = list_next_entry(irq_name, list); 341 } 342 } 343 } 344 345 int afu_register_irqs(struct cxl_context *ctx, u32 count) 346 { 347 int rc; 348 349 rc = afu_allocate_irqs(ctx, count); 350 if (rc) 351 return rc; 352 353 afu_register_hwirqs(ctx); 354 return 0; 355 } 356 357 void afu_release_irqs(struct cxl_context *ctx, void *cookie) 358 { 359 irq_hw_number_t hwirq; 360 unsigned int virq; 361 int r, i; 362 363 for (r = afu_irq_range_start(); r < CXL_IRQ_RANGES; r++) { 364 hwirq = ctx->irqs.offset[r]; 365 for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) { 366 virq = irq_find_mapping(NULL, hwirq); 367 if (virq) 368 cxl_unmap_irq(virq, cookie); 369 } 370 } 371 372 afu_irq_name_free(ctx); 373 cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter); 374 375 ctx->irq_count = 0; 376 } 377