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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/*
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 * Copyright (C) Red Hat Inc., 2014. All rights reserved.
8 * Authors:
9 * Vivek Goyal <vgoyal@redhat.com>
10 *
11 */
12
13#define pr_fmt(fmt) "kexec: " fmt
14
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/smp.h>
18#include <linux/reboot.h>
19#include <linux/kexec.h>
20#include <linux/delay.h>
21#include <linux/elf.h>
22#include <linux/elfcore.h>
23#include <linux/export.h>
24#include <linux/slab.h>
25#include <linux/vmalloc.h>
26
27#include <asm/processor.h>
28#include <asm/hardirq.h>
29#include <asm/nmi.h>
30#include <asm/hw_irq.h>
31#include <asm/apic.h>
32#include <asm/e820/types.h>
33#include <asm/io_apic.h>
34#include <asm/hpet.h>
35#include <linux/kdebug.h>
36#include <asm/cpu.h>
37#include <asm/reboot.h>
38#include <asm/virtext.h>
39#include <asm/intel_pt.h>
40
41/* Used while preparing memory map entries for second kernel */
42struct crash_memmap_data {
43 struct boot_params *params;
44 /* Type of memory */
45 unsigned int type;
46};
47
48/*
49 * This is used to VMCLEAR all VMCSs loaded on the
50 * processor. And when loading kvm_intel module, the
51 * callback function pointer will be assigned.
52 *
53 * protected by rcu.
54 */
55crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
56EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
57unsigned long crash_zero_bytes;
58
59static inline void cpu_crash_vmclear_loaded_vmcss(void)
60{
61 crash_vmclear_fn *do_vmclear_operation = NULL;
62
63 rcu_read_lock();
64 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
65 if (do_vmclear_operation)
66 do_vmclear_operation();
67 rcu_read_unlock();
68}
69
70#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
71
72static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
73{
74#ifdef CONFIG_X86_32
75 struct pt_regs fixed_regs;
76
77 if (!user_mode(regs)) {
78 crash_fixup_ss_esp(&fixed_regs, regs);
79 regs = &fixed_regs;
80 }
81#endif
82 crash_save_cpu(regs, cpu);
83
84 /*
85 * VMCLEAR VMCSs loaded on all cpus if needed.
86 */
87 cpu_crash_vmclear_loaded_vmcss();
88
89 /* Disable VMX or SVM if needed.
90 *
91 * We need to disable virtualization on all CPUs.
92 * Having VMX or SVM enabled on any CPU may break rebooting
93 * after the kdump kernel has finished its task.
94 */
95 cpu_emergency_vmxoff();
96 cpu_emergency_svm_disable();
97
98 /*
99 * Disable Intel PT to stop its logging
100 */
101 cpu_emergency_stop_pt();
102
103 disable_local_APIC();
104}
105
106void kdump_nmi_shootdown_cpus(void)
107{
108 nmi_shootdown_cpus(kdump_nmi_callback);
109
110 disable_local_APIC();
111}
112
113/* Override the weak function in kernel/panic.c */
114void crash_smp_send_stop(void)
115{
116 static int cpus_stopped;
117
118 if (cpus_stopped)
119 return;
120
121 if (smp_ops.crash_stop_other_cpus)
122 smp_ops.crash_stop_other_cpus();
123 else
124 smp_send_stop();
125
126 cpus_stopped = 1;
127}
128
129#else
130void crash_smp_send_stop(void)
131{
132 /* There are no cpus to shootdown */
133}
134#endif
135
136void native_machine_crash_shutdown(struct pt_regs *regs)
137{
138 /* This function is only called after the system
139 * has panicked or is otherwise in a critical state.
140 * The minimum amount of code to allow a kexec'd kernel
141 * to run successfully needs to happen here.
142 *
143 * In practice this means shooting down the other cpus in
144 * an SMP system.
145 */
146 /* The kernel is broken so disable interrupts */
147 local_irq_disable();
148
149 crash_smp_send_stop();
150
151 /*
152 * VMCLEAR VMCSs loaded on this cpu if needed.
153 */
154 cpu_crash_vmclear_loaded_vmcss();
155
156 /* Booting kdump kernel with VMX or SVM enabled won't work,
157 * because (among other limitations) we can't disable paging
158 * with the virt flags.
159 */
160 cpu_emergency_vmxoff();
161 cpu_emergency_svm_disable();
162
163 /*
164 * Disable Intel PT to stop its logging
165 */
166 cpu_emergency_stop_pt();
167
168#ifdef CONFIG_X86_IO_APIC
169 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
170 ioapic_zap_locks();
171 clear_IO_APIC();
172#endif
173 lapic_shutdown();
174 restore_boot_irq_mode();
175#ifdef CONFIG_HPET_TIMER
176 hpet_disable();
177#endif
178 crash_save_cpu(regs, safe_smp_processor_id());
179}
180
181#ifdef CONFIG_KEXEC_FILE
182static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
183{
184 unsigned int *nr_ranges = arg;
185
186 (*nr_ranges)++;
187 return 0;
188}
189
190/* Gather all the required information to prepare elf headers for ram regions */
191static struct crash_mem *fill_up_crash_elf_data(void)
192{
193 unsigned int nr_ranges = 0;
194 struct crash_mem *cmem;
195
196 walk_system_ram_res(0, -1, &nr_ranges,
197 get_nr_ram_ranges_callback);
198 if (!nr_ranges)
199 return NULL;
200
201 /*
202 * Exclusion of crash region and/or crashk_low_res may cause
203 * another range split. So add extra two slots here.
204 */
205 nr_ranges += 2;
206 cmem = vzalloc(sizeof(struct crash_mem) +
207 sizeof(struct crash_mem_range) * nr_ranges);
208 if (!cmem)
209 return NULL;
210
211 cmem->max_nr_ranges = nr_ranges;
212 cmem->nr_ranges = 0;
213
214 return cmem;
215}
216
217/*
218 * Look for any unwanted ranges between mstart, mend and remove them. This
219 * might lead to split and split ranges are put in cmem->ranges[] array
220 */
221static int elf_header_exclude_ranges(struct crash_mem *cmem)
222{
223 int ret = 0;
224
225 /* Exclude crashkernel region */
226 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
227 if (ret)
228 return ret;
229
230 if (crashk_low_res.end) {
231 ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
232 crashk_low_res.end);
233 if (ret)
234 return ret;
235 }
236
237 return ret;
238}
239
240static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
241{
242 struct crash_mem *cmem = arg;
243
244 cmem->ranges[cmem->nr_ranges].start = res->start;
245 cmem->ranges[cmem->nr_ranges].end = res->end;
246 cmem->nr_ranges++;
247
248 return 0;
249}
250
251/* Prepare elf headers. Return addr and size */
252static int prepare_elf_headers(struct kimage *image, void **addr,
253 unsigned long *sz)
254{
255 struct crash_mem *cmem;
256 Elf64_Ehdr *ehdr;
257 Elf64_Phdr *phdr;
258 int ret, i;
259
260 cmem = fill_up_crash_elf_data();
261 if (!cmem)
262 return -ENOMEM;
263
264 ret = walk_system_ram_res(0, -1, cmem,
265 prepare_elf64_ram_headers_callback);
266 if (ret)
267 goto out;
268
269 /* Exclude unwanted mem ranges */
270 ret = elf_header_exclude_ranges(cmem);
271 if (ret)
272 goto out;
273
274 /* By default prepare 64bit headers */
275 ret = crash_prepare_elf64_headers(cmem,
276 IS_ENABLED(CONFIG_X86_64), addr, sz);
277 if (ret)
278 goto out;
279
280 /*
281 * If a range matches backup region, adjust offset to backup
282 * segment.
283 */
284 ehdr = (Elf64_Ehdr *)*addr;
285 phdr = (Elf64_Phdr *)(ehdr + 1);
286 for (i = 0; i < ehdr->e_phnum; phdr++, i++)
287 if (phdr->p_type == PT_LOAD &&
288 phdr->p_paddr == image->arch.backup_src_start &&
289 phdr->p_memsz == image->arch.backup_src_sz) {
290 phdr->p_offset = image->arch.backup_load_addr;
291 break;
292 }
293out:
294 vfree(cmem);
295 return ret;
296}
297
298static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
299{
300 unsigned int nr_e820_entries;
301
302 nr_e820_entries = params->e820_entries;
303 if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
304 return 1;
305
306 memcpy(¶ms->e820_table[nr_e820_entries], entry,
307 sizeof(struct e820_entry));
308 params->e820_entries++;
309 return 0;
310}
311
312static int memmap_entry_callback(struct resource *res, void *arg)
313{
314 struct crash_memmap_data *cmd = arg;
315 struct boot_params *params = cmd->params;
316 struct e820_entry ei;
317
318 ei.addr = res->start;
319 ei.size = resource_size(res);
320 ei.type = cmd->type;
321 add_e820_entry(params, &ei);
322
323 return 0;
324}
325
326static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
327 unsigned long long mstart,
328 unsigned long long mend)
329{
330 unsigned long start, end;
331 int ret = 0;
332
333 cmem->ranges[0].start = mstart;
334 cmem->ranges[0].end = mend;
335 cmem->nr_ranges = 1;
336
337 /* Exclude Backup region */
338 start = image->arch.backup_load_addr;
339 end = start + image->arch.backup_src_sz - 1;
340 ret = crash_exclude_mem_range(cmem, start, end);
341 if (ret)
342 return ret;
343
344 /* Exclude elf header region */
345 start = image->arch.elf_load_addr;
346 end = start + image->arch.elf_headers_sz - 1;
347 return crash_exclude_mem_range(cmem, start, end);
348}
349
350/* Prepare memory map for crash dump kernel */
351int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
352{
353 int i, ret = 0;
354 unsigned long flags;
355 struct e820_entry ei;
356 struct crash_memmap_data cmd;
357 struct crash_mem *cmem;
358
359 cmem = vzalloc(sizeof(struct crash_mem));
360 if (!cmem)
361 return -ENOMEM;
362
363 memset(&cmd, 0, sizeof(struct crash_memmap_data));
364 cmd.params = params;
365
366 /* Add first 640K segment */
367 ei.addr = image->arch.backup_src_start;
368 ei.size = image->arch.backup_src_sz;
369 ei.type = E820_TYPE_RAM;
370 add_e820_entry(params, &ei);
371
372 /* Add ACPI tables */
373 cmd.type = E820_TYPE_ACPI;
374 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
375 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
376 memmap_entry_callback);
377
378 /* Add ACPI Non-volatile Storage */
379 cmd.type = E820_TYPE_NVS;
380 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
381 memmap_entry_callback);
382
383 /* Add crashk_low_res region */
384 if (crashk_low_res.end) {
385 ei.addr = crashk_low_res.start;
386 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
387 ei.type = E820_TYPE_RAM;
388 add_e820_entry(params, &ei);
389 }
390
391 /* Exclude some ranges from crashk_res and add rest to memmap */
392 ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
393 crashk_res.end);
394 if (ret)
395 goto out;
396
397 for (i = 0; i < cmem->nr_ranges; i++) {
398 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
399
400 /* If entry is less than a page, skip it */
401 if (ei.size < PAGE_SIZE)
402 continue;
403 ei.addr = cmem->ranges[i].start;
404 ei.type = E820_TYPE_RAM;
405 add_e820_entry(params, &ei);
406 }
407
408out:
409 vfree(cmem);
410 return ret;
411}
412
413static int determine_backup_region(struct resource *res, void *arg)
414{
415 struct kimage *image = arg;
416
417 image->arch.backup_src_start = res->start;
418 image->arch.backup_src_sz = resource_size(res);
419
420 /* Expecting only one range for backup region */
421 return 1;
422}
423
424int crash_load_segments(struct kimage *image)
425{
426 int ret;
427 struct kexec_buf kbuf = { .image = image, .buf_min = 0,
428 .buf_max = ULONG_MAX, .top_down = false };
429
430 /*
431 * Determine and load a segment for backup area. First 640K RAM
432 * region is backup source
433 */
434
435 ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
436 image, determine_backup_region);
437
438 /* Zero or postive return values are ok */
439 if (ret < 0)
440 return ret;
441
442 /* Add backup segment. */
443 if (image->arch.backup_src_sz) {
444 kbuf.buffer = &crash_zero_bytes;
445 kbuf.bufsz = sizeof(crash_zero_bytes);
446 kbuf.memsz = image->arch.backup_src_sz;
447 kbuf.buf_align = PAGE_SIZE;
448 /*
449 * Ideally there is no source for backup segment. This is
450 * copied in purgatory after crash. Just add a zero filled
451 * segment for now to make sure checksum logic works fine.
452 */
453 ret = kexec_add_buffer(&kbuf);
454 if (ret)
455 return ret;
456 image->arch.backup_load_addr = kbuf.mem;
457 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
458 image->arch.backup_load_addr,
459 image->arch.backup_src_start, kbuf.memsz);
460 }
461
462 /* Prepare elf headers and add a segment */
463 ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
464 if (ret)
465 return ret;
466
467 image->arch.elf_headers = kbuf.buffer;
468 image->arch.elf_headers_sz = kbuf.bufsz;
469
470 kbuf.memsz = kbuf.bufsz;
471 kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
472 ret = kexec_add_buffer(&kbuf);
473 if (ret) {
474 vfree((void *)image->arch.elf_headers);
475 return ret;
476 }
477 image->arch.elf_load_addr = kbuf.mem;
478 pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
479 image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
480
481 return ret;
482}
483#endif /* CONFIG_KEXEC_FILE */