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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
28#include <asm/processor.h>
29#include <asm/hardirq.h>
30#include <asm/nmi.h>
31#include <asm/hw_irq.h>
32#include <asm/apic.h>
33#include <asm/e820/types.h>
34#include <asm/io_apic.h>
35#include <asm/hpet.h>
36#include <linux/kdebug.h>
37#include <asm/cpu.h>
38#include <asm/reboot.h>
39#include <asm/virtext.h>
40#include <asm/intel_pt.h>
41#include <asm/crash.h>
42
43/* Used while preparing memory map entries for second kernel */
44struct crash_memmap_data {
45 struct boot_params *params;
46 /* Type of memory */
47 unsigned int type;
48};
49
50/*
51 * This is used to VMCLEAR all VMCSs loaded on the
52 * processor. And when loading kvm_intel module, the
53 * callback function pointer will be assigned.
54 *
55 * protected by rcu.
56 */
57crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
58EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
59
60static inline void cpu_crash_vmclear_loaded_vmcss(void)
61{
62 crash_vmclear_fn *do_vmclear_operation = NULL;
63
64 rcu_read_lock();
65 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
66 if (do_vmclear_operation)
67 do_vmclear_operation();
68 rcu_read_unlock();
69}
70
71#if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
72
73static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
74{
75 crash_save_cpu(regs, cpu);
76
77 /*
78 * VMCLEAR VMCSs loaded on all cpus if needed.
79 */
80 cpu_crash_vmclear_loaded_vmcss();
81
82 /* Disable VMX or SVM if needed.
83 *
84 * We need to disable virtualization on all CPUs.
85 * Having VMX or SVM enabled on any CPU may break rebooting
86 * after the kdump kernel has finished its task.
87 */
88 cpu_emergency_vmxoff();
89 cpu_emergency_svm_disable();
90
91 /*
92 * Disable Intel PT to stop its logging
93 */
94 cpu_emergency_stop_pt();
95
96 disable_local_APIC();
97}
98
99void kdump_nmi_shootdown_cpus(void)
100{
101 nmi_shootdown_cpus(kdump_nmi_callback);
102
103 disable_local_APIC();
104}
105
106/* Override the weak function in kernel/panic.c */
107void crash_smp_send_stop(void)
108{
109 static int cpus_stopped;
110
111 if (cpus_stopped)
112 return;
113
114 if (smp_ops.crash_stop_other_cpus)
115 smp_ops.crash_stop_other_cpus();
116 else
117 smp_send_stop();
118
119 cpus_stopped = 1;
120}
121
122#else
123void crash_smp_send_stop(void)
124{
125 /* There are no cpus to shootdown */
126}
127#endif
128
129void native_machine_crash_shutdown(struct pt_regs *regs)
130{
131 /* This function is only called after the system
132 * has panicked or is otherwise in a critical state.
133 * The minimum amount of code to allow a kexec'd kernel
134 * to run successfully needs to happen here.
135 *
136 * In practice this means shooting down the other cpus in
137 * an SMP system.
138 */
139 /* The kernel is broken so disable interrupts */
140 local_irq_disable();
141
142 crash_smp_send_stop();
143
144 /*
145 * VMCLEAR VMCSs loaded on this cpu if needed.
146 */
147 cpu_crash_vmclear_loaded_vmcss();
148
149 /* Booting kdump kernel with VMX or SVM enabled won't work,
150 * because (among other limitations) we can't disable paging
151 * with the virt flags.
152 */
153 cpu_emergency_vmxoff();
154 cpu_emergency_svm_disable();
155
156 /*
157 * Disable Intel PT to stop its logging
158 */
159 cpu_emergency_stop_pt();
160
161#ifdef CONFIG_X86_IO_APIC
162 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
163 ioapic_zap_locks();
164 clear_IO_APIC();
165#endif
166 lapic_shutdown();
167 restore_boot_irq_mode();
168#ifdef CONFIG_HPET_TIMER
169 hpet_disable();
170#endif
171 crash_save_cpu(regs, safe_smp_processor_id());
172}
173
174#ifdef CONFIG_KEXEC_FILE
175
176static unsigned long crash_zero_bytes;
177
178static 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 */
187static 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,
193 get_nr_ram_ranges_callback);
194 if (!nr_ranges)
195 return NULL;
196
197 /*
198 * Exclusion of crash region and/or crashk_low_res may cause
199 * another range split. So add extra two slots here.
200 */
201 nr_ranges += 2;
202 cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
203 if (!cmem)
204 return NULL;
205
206 cmem->max_nr_ranges = nr_ranges;
207 cmem->nr_ranges = 0;
208
209 return cmem;
210}
211
212/*
213 * Look for any unwanted ranges between mstart, mend and remove them. This
214 * might lead to split and split ranges are put in cmem->ranges[] array
215 */
216static int elf_header_exclude_ranges(struct crash_mem *cmem)
217{
218 int ret = 0;
219
220 /* Exclude crashkernel region */
221 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
222 if (ret)
223 return ret;
224
225 if (crashk_low_res.end) {
226 ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
227 crashk_low_res.end);
228 }
229
230 return ret;
231}
232
233static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
234{
235 struct crash_mem *cmem = arg;
236
237 cmem->ranges[cmem->nr_ranges].start = res->start;
238 cmem->ranges[cmem->nr_ranges].end = res->end;
239 cmem->nr_ranges++;
240
241 return 0;
242}
243
244/* Prepare elf headers. Return addr and size */
245static int prepare_elf_headers(struct kimage *image, void **addr,
246 unsigned long *sz)
247{
248 struct crash_mem *cmem;
249 Elf64_Ehdr *ehdr;
250 Elf64_Phdr *phdr;
251 int ret, i;
252
253 cmem = fill_up_crash_elf_data();
254 if (!cmem)
255 return -ENOMEM;
256
257 ret = walk_system_ram_res(0, -1, cmem,
258 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,
269 IS_ENABLED(CONFIG_X86_64), addr, sz);
270 if (ret)
271 goto out;
272
273 /*
274 * If a range matches backup region, adjust offset to backup
275 * segment.
276 */
277 ehdr = (Elf64_Ehdr *)*addr;
278 phdr = (Elf64_Phdr *)(ehdr + 1);
279 for (i = 0; i < ehdr->e_phnum; phdr++, i++)
280 if (phdr->p_type == PT_LOAD &&
281 phdr->p_paddr == image->arch.backup_src_start &&
282 phdr->p_memsz == image->arch.backup_src_sz) {
283 phdr->p_offset = image->arch.backup_load_addr;
284 break;
285 }
286out:
287 vfree(cmem);
288 return ret;
289}
290
291static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
292{
293 unsigned int nr_e820_entries;
294
295 nr_e820_entries = params->e820_entries;
296 if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
297 return 1;
298
299 memcpy(¶ms->e820_table[nr_e820_entries], entry,
300 sizeof(struct e820_entry));
301 params->e820_entries++;
302 return 0;
303}
304
305static int memmap_entry_callback(struct resource *res, void *arg)
306{
307 struct crash_memmap_data *cmd = arg;
308 struct boot_params *params = cmd->params;
309 struct e820_entry ei;
310
311 ei.addr = res->start;
312 ei.size = resource_size(res);
313 ei.type = cmd->type;
314 add_e820_entry(params, &ei);
315
316 return 0;
317}
318
319static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
320 unsigned long long mstart,
321 unsigned long long mend)
322{
323 unsigned long start, end;
324 int ret = 0;
325
326 cmem->ranges[0].start = mstart;
327 cmem->ranges[0].end = mend;
328 cmem->nr_ranges = 1;
329
330 /* Exclude Backup region */
331 start = image->arch.backup_load_addr;
332 end = start + image->arch.backup_src_sz - 1;
333 ret = crash_exclude_mem_range(cmem, start, end);
334 if (ret)
335 return ret;
336
337 /* Exclude elf header region */
338 start = image->arch.elf_load_addr;
339 end = start + image->arch.elf_headers_sz - 1;
340 return crash_exclude_mem_range(cmem, start, end);
341}
342
343/* Prepare memory map for crash dump kernel */
344int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
345{
346 int i, ret = 0;
347 unsigned long flags;
348 struct e820_entry ei;
349 struct crash_memmap_data cmd;
350 struct crash_mem *cmem;
351
352 cmem = vzalloc(sizeof(struct crash_mem));
353 if (!cmem)
354 return -ENOMEM;
355
356 memset(&cmd, 0, sizeof(struct crash_memmap_data));
357 cmd.params = params;
358
359 /* Add first 640K segment */
360 ei.addr = image->arch.backup_src_start;
361 ei.size = image->arch.backup_src_sz;
362 ei.type = E820_TYPE_RAM;
363 add_e820_entry(params, &ei);
364
365 /* Add ACPI tables */
366 cmd.type = E820_TYPE_ACPI;
367 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
368 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
369 memmap_entry_callback);
370
371 /* Add ACPI Non-volatile Storage */
372 cmd.type = E820_TYPE_NVS;
373 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
374 memmap_entry_callback);
375
376 /* Add e820 reserved ranges */
377 cmd.type = E820_TYPE_RESERVED;
378 flags = IORESOURCE_MEM;
379 walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd,
380 memmap_entry_callback);
381
382 /* Add crashk_low_res region */
383 if (crashk_low_res.end) {
384 ei.addr = crashk_low_res.start;
385 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
386 ei.type = E820_TYPE_RAM;
387 add_e820_entry(params, &ei);
388 }
389
390 /* Exclude some ranges from crashk_res and add rest to memmap */
391 ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
392 crashk_res.end);
393 if (ret)
394 goto out;
395
396 for (i = 0; i < cmem->nr_ranges; i++) {
397 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
398
399 /* If entry is less than a page, skip it */
400 if (ei.size < PAGE_SIZE)
401 continue;
402 ei.addr = cmem->ranges[i].start;
403 ei.type = E820_TYPE_RAM;
404 add_e820_entry(params, &ei);
405 }
406
407out:
408 vfree(cmem);
409 return ret;
410}
411
412static int determine_backup_region(struct resource *res, void *arg)
413{
414 struct kimage *image = arg;
415
416 image->arch.backup_src_start = res->start;
417 image->arch.backup_src_sz = resource_size(res);
418
419 /* Expecting only one range for backup region */
420 return 1;
421}
422
423int crash_load_segments(struct kimage *image)
424{
425 int ret;
426 struct kexec_buf kbuf = { .image = image, .buf_min = 0,
427 .buf_max = ULONG_MAX, .top_down = false };
428
429 /*
430 * Determine and load a segment for backup area. First 640K RAM
431 * region is backup source
432 */
433
434 ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
435 image, determine_backup_region);
436
437 /* Zero or postive return values are ok */
438 if (ret < 0)
439 return ret;
440
441 /* Add backup segment. */
442 if (image->arch.backup_src_sz) {
443 kbuf.buffer = &crash_zero_bytes;
444 kbuf.bufsz = sizeof(crash_zero_bytes);
445 kbuf.memsz = image->arch.backup_src_sz;
446 kbuf.buf_align = PAGE_SIZE;
447 /*
448 * Ideally there is no source for backup segment. This is
449 * copied in purgatory after crash. Just add a zero filled
450 * segment for now to make sure checksum logic works fine.
451 */
452 ret = kexec_add_buffer(&kbuf);
453 if (ret)
454 return ret;
455 image->arch.backup_load_addr = kbuf.mem;
456 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
457 image->arch.backup_load_addr,
458 image->arch.backup_src_start, kbuf.memsz);
459 }
460
461 /* Prepare elf headers and add a segment */
462 ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
463 if (ret)
464 return ret;
465
466 image->arch.elf_headers = kbuf.buffer;
467 image->arch.elf_headers_sz = kbuf.bufsz;
468
469 kbuf.memsz = kbuf.bufsz;
470 kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
471 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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 */