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1/*
2 * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
3 *
4 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
5 *
6 * Copyright (C) IBM Corporation, 2004. All rights reserved.
7 *
8 */
9
10#include <linux/init.h>
11#include <linux/types.h>
12#include <linux/kernel.h>
13#include <linux/smp.h>
14#include <linux/reboot.h>
15#include <linux/kexec.h>
16#include <linux/delay.h>
17#include <linux/elf.h>
18#include <linux/elfcore.h>
19
20#include <asm/processor.h>
21#include <asm/hardirq.h>
22#include <asm/nmi.h>
23#include <asm/hw_irq.h>
24#include <asm/apic.h>
25#include <asm/hpet.h>
26#include <linux/kdebug.h>
27#include <asm/cpu.h>
28#include <asm/reboot.h>
29#include <asm/virtext.h>
30
31int in_crash_kexec;
32
33#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
34
35static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
36{
37#ifdef CONFIG_X86_32
38 struct pt_regs fixed_regs;
39#endif
40
41#ifdef CONFIG_X86_32
42 if (!user_mode_vm(regs)) {
43 crash_fixup_ss_esp(&fixed_regs, regs);
44 regs = &fixed_regs;
45 }
46#endif
47 crash_save_cpu(regs, cpu);
48
49 /* Disable VMX or SVM if needed.
50 *
51 * We need to disable virtualization on all CPUs.
52 * Having VMX or SVM enabled on any CPU may break rebooting
53 * after the kdump kernel has finished its task.
54 */
55 cpu_emergency_vmxoff();
56 cpu_emergency_svm_disable();
57
58 disable_local_APIC();
59}
60
61static void kdump_nmi_shootdown_cpus(void)
62{
63 in_crash_kexec = 1;
64 nmi_shootdown_cpus(kdump_nmi_callback);
65
66 disable_local_APIC();
67}
68
69#else
70static void kdump_nmi_shootdown_cpus(void)
71{
72 /* There are no cpus to shootdown */
73}
74#endif
75
76void native_machine_crash_shutdown(struct pt_regs *regs)
77{
78 /* This function is only called after the system
79 * has panicked or is otherwise in a critical state.
80 * The minimum amount of code to allow a kexec'd kernel
81 * to run successfully needs to happen here.
82 *
83 * In practice this means shooting down the other cpus in
84 * an SMP system.
85 */
86 /* The kernel is broken so disable interrupts */
87 local_irq_disable();
88
89 kdump_nmi_shootdown_cpus();
90
91 /* Booting kdump kernel with VMX or SVM enabled won't work,
92 * because (among other limitations) we can't disable paging
93 * with the virt flags.
94 */
95 cpu_emergency_vmxoff();
96 cpu_emergency_svm_disable();
97
98 lapic_shutdown();
99#if defined(CONFIG_X86_IO_APIC)
100 disable_IO_APIC();
101#endif
102#ifdef CONFIG_HPET_TIMER
103 hpet_disable();
104#endif
105 crash_save_cpu(regs, safe_smp_processor_id());
106}
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/bootparam.h>
30#include <asm/processor.h>
31#include <asm/hardirq.h>
32#include <asm/nmi.h>
33#include <asm/hw_irq.h>
34#include <asm/apic.h>
35#include <asm/e820/types.h>
36#include <asm/io_apic.h>
37#include <asm/hpet.h>
38#include <linux/kdebug.h>
39#include <asm/cpu.h>
40#include <asm/reboot.h>
41#include <asm/intel_pt.h>
42#include <asm/crash.h>
43#include <asm/cmdline.h>
44#include <asm/sev.h>
45
46/* Used while preparing memory map entries for second kernel */
47struct crash_memmap_data {
48 struct boot_params *params;
49 /* Type of memory */
50 unsigned int type;
51};
52
53#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
54
55static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
56{
57 crash_save_cpu(regs, cpu);
58
59 /*
60 * Disable Intel PT to stop its logging
61 */
62 cpu_emergency_stop_pt();
63
64 kdump_sev_callback();
65
66 disable_local_APIC();
67}
68
69void kdump_nmi_shootdown_cpus(void)
70{
71 nmi_shootdown_cpus(kdump_nmi_callback);
72
73 disable_local_APIC();
74}
75
76/* Override the weak function in kernel/panic.c */
77void crash_smp_send_stop(void)
78{
79 static int cpus_stopped;
80
81 if (cpus_stopped)
82 return;
83
84 if (smp_ops.crash_stop_other_cpus)
85 smp_ops.crash_stop_other_cpus();
86 else
87 smp_send_stop();
88
89 cpus_stopped = 1;
90}
91
92#else
93void crash_smp_send_stop(void)
94{
95 /* There are no cpus to shootdown */
96}
97#endif
98
99void native_machine_crash_shutdown(struct pt_regs *regs)
100{
101 /* This function is only called after the system
102 * has panicked or is otherwise in a critical state.
103 * The minimum amount of code to allow a kexec'd kernel
104 * to run successfully needs to happen here.
105 *
106 * In practice this means shooting down the other cpus in
107 * an SMP system.
108 */
109 /* The kernel is broken so disable interrupts */
110 local_irq_disable();
111
112 crash_smp_send_stop();
113
114 cpu_emergency_disable_virtualization();
115
116 /*
117 * Disable Intel PT to stop its logging
118 */
119 cpu_emergency_stop_pt();
120
121#ifdef CONFIG_X86_IO_APIC
122 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
123 ioapic_zap_locks();
124 clear_IO_APIC();
125#endif
126 lapic_shutdown();
127 restore_boot_irq_mode();
128#ifdef CONFIG_HPET_TIMER
129 hpet_disable();
130#endif
131 crash_save_cpu(regs, safe_smp_processor_id());
132}
133
134#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_HOTPLUG)
135static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
136{
137 unsigned int *nr_ranges = arg;
138
139 (*nr_ranges)++;
140 return 0;
141}
142
143/* Gather all the required information to prepare elf headers for ram regions */
144static struct crash_mem *fill_up_crash_elf_data(void)
145{
146 unsigned int nr_ranges = 0;
147 struct crash_mem *cmem;
148
149 walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
150 if (!nr_ranges)
151 return NULL;
152
153 /*
154 * Exclusion of crash region and/or crashk_low_res may cause
155 * another range split. So add extra two slots here.
156 */
157 nr_ranges += 2;
158 cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
159 if (!cmem)
160 return NULL;
161
162 cmem->max_nr_ranges = nr_ranges;
163 cmem->nr_ranges = 0;
164
165 return cmem;
166}
167
168/*
169 * Look for any unwanted ranges between mstart, mend and remove them. This
170 * might lead to split and split ranges are put in cmem->ranges[] array
171 */
172static int elf_header_exclude_ranges(struct crash_mem *cmem)
173{
174 int ret = 0;
175
176 /* Exclude the low 1M because it is always reserved */
177 ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
178 if (ret)
179 return ret;
180
181 /* Exclude crashkernel region */
182 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
183 if (ret)
184 return ret;
185
186 if (crashk_low_res.end)
187 ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
188 crashk_low_res.end);
189
190 return ret;
191}
192
193static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
194{
195 struct crash_mem *cmem = arg;
196
197 cmem->ranges[cmem->nr_ranges].start = res->start;
198 cmem->ranges[cmem->nr_ranges].end = res->end;
199 cmem->nr_ranges++;
200
201 return 0;
202}
203
204/* Prepare elf headers. Return addr and size */
205static int prepare_elf_headers(void **addr, unsigned long *sz,
206 unsigned long *nr_mem_ranges)
207{
208 struct crash_mem *cmem;
209 int ret;
210
211 cmem = fill_up_crash_elf_data();
212 if (!cmem)
213 return -ENOMEM;
214
215 ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
216 if (ret)
217 goto out;
218
219 /* Exclude unwanted mem ranges */
220 ret = elf_header_exclude_ranges(cmem);
221 if (ret)
222 goto out;
223
224 /* Return the computed number of memory ranges, for hotplug usage */
225 *nr_mem_ranges = cmem->nr_ranges;
226
227 /* By default prepare 64bit headers */
228 ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
229
230out:
231 vfree(cmem);
232 return ret;
233}
234#endif
235
236#ifdef CONFIG_KEXEC_FILE
237static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
238{
239 unsigned int nr_e820_entries;
240
241 nr_e820_entries = params->e820_entries;
242 if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
243 return 1;
244
245 memcpy(¶ms->e820_table[nr_e820_entries], entry, sizeof(struct e820_entry));
246 params->e820_entries++;
247 return 0;
248}
249
250static int memmap_entry_callback(struct resource *res, void *arg)
251{
252 struct crash_memmap_data *cmd = arg;
253 struct boot_params *params = cmd->params;
254 struct e820_entry ei;
255
256 ei.addr = res->start;
257 ei.size = resource_size(res);
258 ei.type = cmd->type;
259 add_e820_entry(params, &ei);
260
261 return 0;
262}
263
264static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
265 unsigned long long mstart,
266 unsigned long long mend)
267{
268 unsigned long start, end;
269
270 cmem->ranges[0].start = mstart;
271 cmem->ranges[0].end = mend;
272 cmem->nr_ranges = 1;
273
274 /* Exclude elf header region */
275 start = image->elf_load_addr;
276 end = start + image->elf_headers_sz - 1;
277 return crash_exclude_mem_range(cmem, start, end);
278}
279
280/* Prepare memory map for crash dump kernel */
281int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
282{
283 int i, ret = 0;
284 unsigned long flags;
285 struct e820_entry ei;
286 struct crash_memmap_data cmd;
287 struct crash_mem *cmem;
288
289 cmem = vzalloc(struct_size(cmem, ranges, 1));
290 if (!cmem)
291 return -ENOMEM;
292
293 memset(&cmd, 0, sizeof(struct crash_memmap_data));
294 cmd.params = params;
295
296 /* Add the low 1M */
297 cmd.type = E820_TYPE_RAM;
298 flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
299 walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, (1<<20)-1, &cmd,
300 memmap_entry_callback);
301
302 /* Add ACPI tables */
303 cmd.type = E820_TYPE_ACPI;
304 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
305 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
306 memmap_entry_callback);
307
308 /* Add ACPI Non-volatile Storage */
309 cmd.type = E820_TYPE_NVS;
310 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
311 memmap_entry_callback);
312
313 /* Add e820 reserved ranges */
314 cmd.type = E820_TYPE_RESERVED;
315 flags = IORESOURCE_MEM;
316 walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd,
317 memmap_entry_callback);
318
319 /* Add crashk_low_res region */
320 if (crashk_low_res.end) {
321 ei.addr = crashk_low_res.start;
322 ei.size = resource_size(&crashk_low_res);
323 ei.type = E820_TYPE_RAM;
324 add_e820_entry(params, &ei);
325 }
326
327 /* Exclude some ranges from crashk_res and add rest to memmap */
328 ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end);
329 if (ret)
330 goto out;
331
332 for (i = 0; i < cmem->nr_ranges; i++) {
333 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
334
335 /* If entry is less than a page, skip it */
336 if (ei.size < PAGE_SIZE)
337 continue;
338 ei.addr = cmem->ranges[i].start;
339 ei.type = E820_TYPE_RAM;
340 add_e820_entry(params, &ei);
341 }
342
343out:
344 vfree(cmem);
345 return ret;
346}
347
348int crash_load_segments(struct kimage *image)
349{
350 int ret;
351 unsigned long pnum = 0;
352 struct kexec_buf kbuf = { .image = image, .buf_min = 0,
353 .buf_max = ULONG_MAX, .top_down = false };
354
355 /* Prepare elf headers and add a segment */
356 ret = prepare_elf_headers(&kbuf.buffer, &kbuf.bufsz, &pnum);
357 if (ret)
358 return ret;
359
360 image->elf_headers = kbuf.buffer;
361 image->elf_headers_sz = kbuf.bufsz;
362 kbuf.memsz = kbuf.bufsz;
363
364#ifdef CONFIG_CRASH_HOTPLUG
365 /*
366 * The elfcorehdr segment size accounts for VMCOREINFO, kernel_map,
367 * maximum CPUs and maximum memory ranges.
368 */
369 if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
370 pnum = 2 + CONFIG_NR_CPUS_DEFAULT + CONFIG_CRASH_MAX_MEMORY_RANGES;
371 else
372 pnum += 2 + CONFIG_NR_CPUS_DEFAULT;
373
374 if (pnum < (unsigned long)PN_XNUM) {
375 kbuf.memsz = pnum * sizeof(Elf64_Phdr);
376 kbuf.memsz += sizeof(Elf64_Ehdr);
377
378 image->elfcorehdr_index = image->nr_segments;
379
380 /* Mark as usable to crash kernel, else crash kernel fails on boot */
381 image->elf_headers_sz = kbuf.memsz;
382 } else {
383 pr_err("number of Phdrs %lu exceeds max\n", pnum);
384 }
385#endif
386
387 kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
388 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
389 ret = kexec_add_buffer(&kbuf);
390 if (ret)
391 return ret;
392 image->elf_load_addr = kbuf.mem;
393 kexec_dprintk("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
394 image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
395
396 return ret;
397}
398#endif /* CONFIG_KEXEC_FILE */
399
400#ifdef CONFIG_CRASH_HOTPLUG
401
402#undef pr_fmt
403#define pr_fmt(fmt) "crash hp: " fmt
404
405/* These functions provide the value for the sysfs crash_hotplug nodes */
406#ifdef CONFIG_HOTPLUG_CPU
407int arch_crash_hotplug_cpu_support(void)
408{
409 return crash_check_update_elfcorehdr();
410}
411#endif
412
413#ifdef CONFIG_MEMORY_HOTPLUG
414int arch_crash_hotplug_memory_support(void)
415{
416 return crash_check_update_elfcorehdr();
417}
418#endif
419
420unsigned int arch_crash_get_elfcorehdr_size(void)
421{
422 unsigned int sz;
423
424 /* kernel_map, VMCOREINFO and maximum CPUs */
425 sz = 2 + CONFIG_NR_CPUS_DEFAULT;
426 if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
427 sz += CONFIG_CRASH_MAX_MEMORY_RANGES;
428 sz *= sizeof(Elf64_Phdr);
429 return sz;
430}
431
432/**
433 * arch_crash_handle_hotplug_event() - Handle hotplug elfcorehdr changes
434 * @image: a pointer to kexec_crash_image
435 *
436 * Prepare the new elfcorehdr and replace the existing elfcorehdr.
437 */
438void arch_crash_handle_hotplug_event(struct kimage *image)
439{
440 void *elfbuf = NULL, *old_elfcorehdr;
441 unsigned long nr_mem_ranges;
442 unsigned long mem, memsz;
443 unsigned long elfsz = 0;
444
445 /*
446 * As crash_prepare_elf64_headers() has already described all
447 * possible CPUs, there is no need to update the elfcorehdr
448 * for additional CPU changes.
449 */
450 if ((image->file_mode || image->elfcorehdr_updated) &&
451 ((image->hp_action == KEXEC_CRASH_HP_ADD_CPU) ||
452 (image->hp_action == KEXEC_CRASH_HP_REMOVE_CPU)))
453 return;
454
455 /*
456 * Create the new elfcorehdr reflecting the changes to CPU and/or
457 * memory resources.
458 */
459 if (prepare_elf_headers(&elfbuf, &elfsz, &nr_mem_ranges)) {
460 pr_err("unable to create new elfcorehdr");
461 goto out;
462 }
463
464 /*
465 * Obtain address and size of the elfcorehdr segment, and
466 * check it against the new elfcorehdr buffer.
467 */
468 mem = image->segment[image->elfcorehdr_index].mem;
469 memsz = image->segment[image->elfcorehdr_index].memsz;
470 if (elfsz > memsz) {
471 pr_err("update elfcorehdr elfsz %lu > memsz %lu",
472 elfsz, memsz);
473 goto out;
474 }
475
476 /*
477 * Copy new elfcorehdr over the old elfcorehdr at destination.
478 */
479 old_elfcorehdr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
480 if (!old_elfcorehdr) {
481 pr_err("mapping elfcorehdr segment failed\n");
482 goto out;
483 }
484
485 /*
486 * Temporarily invalidate the crash image while the
487 * elfcorehdr is updated.
488 */
489 xchg(&kexec_crash_image, NULL);
490 memcpy_flushcache(old_elfcorehdr, elfbuf, elfsz);
491 xchg(&kexec_crash_image, image);
492 kunmap_local(old_elfcorehdr);
493 pr_debug("updated elfcorehdr\n");
494
495out:
496 vfree(elfbuf);
497}
498#endif