1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Architecture specific (i386/x86_64) functions for kexec based crash dumps. 4 * 5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) 6 * 7 * Copyright (C) IBM Corporation, 2004. All rights reserved. 8 * Copyright (C) Red Hat Inc., 2014. All rights reserved. 9 * Authors: 10 * Vivek Goyal <vgoyal@redhat.com> 11 * 12 */ 13 14 #define pr_fmt(fmt) "kexec: " fmt 15 16 #include <linux/types.h> 17 #include <linux/kernel.h> 18 #include <linux/smp.h> 19 #include <linux/reboot.h> 20 #include <linux/kexec.h> 21 #include <linux/delay.h> 22 #include <linux/elf.h> 23 #include <linux/elfcore.h> 24 #include <linux/export.h> 25 #include <linux/slab.h> 26 #include <linux/vmalloc.h> 27 #include <linux/memblock.h> 28 29 #include <asm/processor.h> 30 #include <asm/hardirq.h> 31 #include <asm/nmi.h> 32 #include <asm/hw_irq.h> 33 #include <asm/apic.h> 34 #include <asm/e820/types.h> 35 #include <asm/io_apic.h> 36 #include <asm/hpet.h> 37 #include <linux/kdebug.h> 38 #include <asm/cpu.h> 39 #include <asm/reboot.h> 40 #include <asm/virtext.h> 41 #include <asm/intel_pt.h> 42 #include <asm/crash.h> 43 #include <asm/cmdline.h> 44 45 /* Used while preparing memory map entries for second kernel */ 46 struct crash_memmap_data { 47 struct boot_params *params; 48 /* Type of memory */ 49 unsigned int type; 50 }; 51 52 /* 53 * This is used to VMCLEAR all VMCSs loaded on the 54 * processor. And when loading kvm_intel module, the 55 * callback function pointer will be assigned. 56 * 57 * protected by rcu. 58 */ 59 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL; 60 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss); 61 62 static inline void cpu_crash_vmclear_loaded_vmcss(void) 63 { 64 crash_vmclear_fn *do_vmclear_operation = NULL; 65 66 rcu_read_lock(); 67 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss); 68 if (do_vmclear_operation) 69 do_vmclear_operation(); 70 rcu_read_unlock(); 71 } 72 73 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC) 74 75 static void kdump_nmi_callback(int cpu, struct pt_regs *regs) 76 { 77 crash_save_cpu(regs, cpu); 78 79 /* 80 * VMCLEAR VMCSs loaded on all cpus if needed. 81 */ 82 cpu_crash_vmclear_loaded_vmcss(); 83 84 /* Disable VMX or SVM if needed. 85 * 86 * We need to disable virtualization on all CPUs. 87 * Having VMX or SVM enabled on any CPU may break rebooting 88 * after the kdump kernel has finished its task. 89 */ 90 cpu_emergency_vmxoff(); 91 cpu_emergency_svm_disable(); 92 93 /* 94 * Disable Intel PT to stop its logging 95 */ 96 cpu_emergency_stop_pt(); 97 98 disable_local_APIC(); 99 } 100 101 void kdump_nmi_shootdown_cpus(void) 102 { 103 nmi_shootdown_cpus(kdump_nmi_callback); 104 105 disable_local_APIC(); 106 } 107 108 /* Override the weak function in kernel/panic.c */ 109 void crash_smp_send_stop(void) 110 { 111 static int cpus_stopped; 112 113 if (cpus_stopped) 114 return; 115 116 if (smp_ops.crash_stop_other_cpus) 117 smp_ops.crash_stop_other_cpus(); 118 else 119 smp_send_stop(); 120 121 cpus_stopped = 1; 122 } 123 124 #else 125 void crash_smp_send_stop(void) 126 { 127 /* There are no cpus to shootdown */ 128 } 129 #endif 130 131 void native_machine_crash_shutdown(struct pt_regs *regs) 132 { 133 /* This function is only called after the system 134 * has panicked or is otherwise in a critical state. 135 * The minimum amount of code to allow a kexec'd kernel 136 * to run successfully needs to happen here. 137 * 138 * In practice this means shooting down the other cpus in 139 * an SMP system. 140 */ 141 /* The kernel is broken so disable interrupts */ 142 local_irq_disable(); 143 144 crash_smp_send_stop(); 145 146 /* 147 * VMCLEAR VMCSs loaded on this cpu if needed. 148 */ 149 cpu_crash_vmclear_loaded_vmcss(); 150 151 /* Booting kdump kernel with VMX or SVM enabled won't work, 152 * because (among other limitations) we can't disable paging 153 * with the virt flags. 154 */ 155 cpu_emergency_vmxoff(); 156 cpu_emergency_svm_disable(); 157 158 /* 159 * Disable Intel PT to stop its logging 160 */ 161 cpu_emergency_stop_pt(); 162 163 #ifdef CONFIG_X86_IO_APIC 164 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */ 165 ioapic_zap_locks(); 166 clear_IO_APIC(); 167 #endif 168 lapic_shutdown(); 169 restore_boot_irq_mode(); 170 #ifdef CONFIG_HPET_TIMER 171 hpet_disable(); 172 #endif 173 crash_save_cpu(regs, safe_smp_processor_id()); 174 } 175 176 #ifdef CONFIG_KEXEC_FILE 177 178 static int get_nr_ram_ranges_callback(struct resource *res, void *arg) 179 { 180 unsigned int *nr_ranges = arg; 181 182 (*nr_ranges)++; 183 return 0; 184 } 185 186 /* Gather all the required information to prepare elf headers for ram regions */ 187 static struct crash_mem *fill_up_crash_elf_data(void) 188 { 189 unsigned int nr_ranges = 0; 190 struct crash_mem *cmem; 191 192 walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); 193 if (!nr_ranges) 194 return NULL; 195 196 /* 197 * Exclusion of crash region and/or crashk_low_res may cause 198 * another range split. So add extra two slots here. 199 */ 200 nr_ranges += 2; 201 cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); 202 if (!cmem) 203 return NULL; 204 205 cmem->max_nr_ranges = nr_ranges; 206 cmem->nr_ranges = 0; 207 208 return cmem; 209 } 210 211 /* 212 * Look for any unwanted ranges between mstart, mend and remove them. This 213 * might lead to split and split ranges are put in cmem->ranges[] array 214 */ 215 static int elf_header_exclude_ranges(struct crash_mem *cmem) 216 { 217 int ret = 0; 218 219 /* Exclude the low 1M because it is always reserved */ 220 ret = crash_exclude_mem_range(cmem, 0, (1<<20)-1); 221 if (ret) 222 return ret; 223 224 /* Exclude crashkernel region */ 225 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); 226 if (ret) 227 return ret; 228 229 if (crashk_low_res.end) 230 ret = crash_exclude_mem_range(cmem, crashk_low_res.start, 231 crashk_low_res.end); 232 233 return ret; 234 } 235 236 static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) 237 { 238 struct crash_mem *cmem = arg; 239 240 cmem->ranges[cmem->nr_ranges].start = res->start; 241 cmem->ranges[cmem->nr_ranges].end = res->end; 242 cmem->nr_ranges++; 243 244 return 0; 245 } 246 247 /* Prepare elf headers. Return addr and size */ 248 static int prepare_elf_headers(struct kimage *image, void **addr, 249 unsigned long *sz) 250 { 251 struct crash_mem *cmem; 252 int ret; 253 254 cmem = fill_up_crash_elf_data(); 255 if (!cmem) 256 return -ENOMEM; 257 258 ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); 259 if (ret) 260 goto out; 261 262 /* Exclude unwanted mem ranges */ 263 ret = elf_header_exclude_ranges(cmem); 264 if (ret) 265 goto out; 266 267 /* By default prepare 64bit headers */ 268 ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz); 269 270 out: 271 vfree(cmem); 272 return ret; 273 } 274 275 static int add_e820_entry(struct boot_params *params, struct e820_entry *entry) 276 { 277 unsigned int nr_e820_entries; 278 279 nr_e820_entries = params->e820_entries; 280 if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE) 281 return 1; 282 283 memcpy(¶ms->e820_table[nr_e820_entries], entry, sizeof(struct e820_entry)); 284 params->e820_entries++; 285 return 0; 286 } 287 288 static int memmap_entry_callback(struct resource *res, void *arg) 289 { 290 struct crash_memmap_data *cmd = arg; 291 struct boot_params *params = cmd->params; 292 struct e820_entry ei; 293 294 ei.addr = res->start; 295 ei.size = resource_size(res); 296 ei.type = cmd->type; 297 add_e820_entry(params, &ei); 298 299 return 0; 300 } 301 302 static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem, 303 unsigned long long mstart, 304 unsigned long long mend) 305 { 306 unsigned long start, end; 307 308 cmem->ranges[0].start = mstart; 309 cmem->ranges[0].end = mend; 310 cmem->nr_ranges = 1; 311 312 /* Exclude elf header region */ 313 start = image->elf_load_addr; 314 end = start + image->elf_headers_sz - 1; 315 return crash_exclude_mem_range(cmem, start, end); 316 } 317 318 /* Prepare memory map for crash dump kernel */ 319 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params) 320 { 321 int i, ret = 0; 322 unsigned long flags; 323 struct e820_entry ei; 324 struct crash_memmap_data cmd; 325 struct crash_mem *cmem; 326 327 cmem = vzalloc(struct_size(cmem, ranges, 1)); 328 if (!cmem) 329 return -ENOMEM; 330 331 memset(&cmd, 0, sizeof(struct crash_memmap_data)); 332 cmd.params = params; 333 334 /* Add the low 1M */ 335 cmd.type = E820_TYPE_RAM; 336 flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; 337 walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, (1<<20)-1, &cmd, 338 memmap_entry_callback); 339 340 /* Add ACPI tables */ 341 cmd.type = E820_TYPE_ACPI; 342 flags = IORESOURCE_MEM | IORESOURCE_BUSY; 343 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd, 344 memmap_entry_callback); 345 346 /* Add ACPI Non-volatile Storage */ 347 cmd.type = E820_TYPE_NVS; 348 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd, 349 memmap_entry_callback); 350 351 /* Add e820 reserved ranges */ 352 cmd.type = E820_TYPE_RESERVED; 353 flags = IORESOURCE_MEM; 354 walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd, 355 memmap_entry_callback); 356 357 /* Add crashk_low_res region */ 358 if (crashk_low_res.end) { 359 ei.addr = crashk_low_res.start; 360 ei.size = resource_size(&crashk_low_res); 361 ei.type = E820_TYPE_RAM; 362 add_e820_entry(params, &ei); 363 } 364 365 /* Exclude some ranges from crashk_res and add rest to memmap */ 366 ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end); 367 if (ret) 368 goto out; 369 370 for (i = 0; i < cmem->nr_ranges; i++) { 371 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1; 372 373 /* If entry is less than a page, skip it */ 374 if (ei.size < PAGE_SIZE) 375 continue; 376 ei.addr = cmem->ranges[i].start; 377 ei.type = E820_TYPE_RAM; 378 add_e820_entry(params, &ei); 379 } 380 381 out: 382 vfree(cmem); 383 return ret; 384 } 385 386 int crash_load_segments(struct kimage *image) 387 { 388 int ret; 389 struct kexec_buf kbuf = { .image = image, .buf_min = 0, 390 .buf_max = ULONG_MAX, .top_down = false }; 391 392 /* Prepare elf headers and add a segment */ 393 ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz); 394 if (ret) 395 return ret; 396 397 image->elf_headers = kbuf.buffer; 398 image->elf_headers_sz = kbuf.bufsz; 399 400 kbuf.memsz = kbuf.bufsz; 401 kbuf.buf_align = ELF_CORE_HEADER_ALIGN; 402 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; 403 ret = kexec_add_buffer(&kbuf); 404 if (ret) 405 return ret; 406 image->elf_load_addr = kbuf.mem; 407 pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 408 image->elf_load_addr, kbuf.bufsz, kbuf.memsz); 409 410 return ret; 411 } 412 #endif /* CONFIG_KEXEC_FILE */ 413