1 // SPDX-License-Identifier: GPL-2.0-only
3 * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
7 * Copyright (C) IBM Corporation, 2004. All rights reserved.
8 * Copyright (C) Red Hat Inc., 2014. All rights reserved.
10 * Vivek Goyal <vgoyal@redhat.com>
14 #define pr_fmt(fmt) "kexec: " fmt
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>
28 #include <asm/processor.h>
29 #include <asm/hardirq.h>
31 #include <asm/hw_irq.h>
33 #include <asm/e820/types.h>
34 #include <asm/io_apic.h>
36 #include <linux/kdebug.h>
38 #include <asm/reboot.h>
39 #include <asm/virtext.h>
40 #include <asm/intel_pt.h>
41 #include <asm/crash.h>
43 /* Used while preparing memory map entries for second kernel */
44 struct crash_memmap_data {
45 struct boot_params *params;
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.
57 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
58 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
60 static inline void cpu_crash_vmclear_loaded_vmcss(void)
62 crash_vmclear_fn *do_vmclear_operation = NULL;
65 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
66 if (do_vmclear_operation)
67 do_vmclear_operation();
71 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
73 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
76 struct pt_regs fixed_regs;
78 if (!user_mode(regs)) {
79 crash_fixup_ss_esp(&fixed_regs, regs);
83 crash_save_cpu(regs, cpu);
86 * VMCLEAR VMCSs loaded on all cpus if needed.
88 cpu_crash_vmclear_loaded_vmcss();
90 /* Disable VMX or SVM if needed.
92 * We need to disable virtualization on all CPUs.
93 * Having VMX or SVM enabled on any CPU may break rebooting
94 * after the kdump kernel has finished its task.
96 cpu_emergency_vmxoff();
97 cpu_emergency_svm_disable();
100 * Disable Intel PT to stop its logging
102 cpu_emergency_stop_pt();
104 disable_local_APIC();
107 void kdump_nmi_shootdown_cpus(void)
109 nmi_shootdown_cpus(kdump_nmi_callback);
111 disable_local_APIC();
114 /* Override the weak function in kernel/panic.c */
115 void crash_smp_send_stop(void)
117 static int cpus_stopped;
122 if (smp_ops.crash_stop_other_cpus)
123 smp_ops.crash_stop_other_cpus();
131 void crash_smp_send_stop(void)
133 /* There are no cpus to shootdown */
137 void native_machine_crash_shutdown(struct pt_regs *regs)
139 /* This function is only called after the system
140 * has panicked or is otherwise in a critical state.
141 * The minimum amount of code to allow a kexec'd kernel
142 * to run successfully needs to happen here.
144 * In practice this means shooting down the other cpus in
147 /* The kernel is broken so disable interrupts */
150 crash_smp_send_stop();
153 * VMCLEAR VMCSs loaded on this cpu if needed.
155 cpu_crash_vmclear_loaded_vmcss();
157 /* Booting kdump kernel with VMX or SVM enabled won't work,
158 * because (among other limitations) we can't disable paging
159 * with the virt flags.
161 cpu_emergency_vmxoff();
162 cpu_emergency_svm_disable();
165 * Disable Intel PT to stop its logging
167 cpu_emergency_stop_pt();
169 #ifdef CONFIG_X86_IO_APIC
170 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
175 restore_boot_irq_mode();
176 #ifdef CONFIG_HPET_TIMER
179 crash_save_cpu(regs, safe_smp_processor_id());
182 #ifdef CONFIG_KEXEC_FILE
184 static unsigned long crash_zero_bytes;
186 static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
188 unsigned int *nr_ranges = arg;
194 /* Gather all the required information to prepare elf headers for ram regions */
195 static struct crash_mem *fill_up_crash_elf_data(void)
197 unsigned int nr_ranges = 0;
198 struct crash_mem *cmem;
200 walk_system_ram_res(0, -1, &nr_ranges,
201 get_nr_ram_ranges_callback);
206 * Exclusion of crash region and/or crashk_low_res may cause
207 * another range split. So add extra two slots here.
210 cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
214 cmem->max_nr_ranges = nr_ranges;
221 * Look for any unwanted ranges between mstart, mend and remove them. This
222 * might lead to split and split ranges are put in cmem->ranges[] array
224 static int elf_header_exclude_ranges(struct crash_mem *cmem)
228 /* Exclude crashkernel region */
229 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
233 if (crashk_low_res.end) {
234 ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
243 static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
245 struct crash_mem *cmem = arg;
247 cmem->ranges[cmem->nr_ranges].start = res->start;
248 cmem->ranges[cmem->nr_ranges].end = res->end;
254 /* Prepare elf headers. Return addr and size */
255 static int prepare_elf_headers(struct kimage *image, void **addr,
258 struct crash_mem *cmem;
263 cmem = fill_up_crash_elf_data();
267 ret = walk_system_ram_res(0, -1, cmem,
268 prepare_elf64_ram_headers_callback);
272 /* Exclude unwanted mem ranges */
273 ret = elf_header_exclude_ranges(cmem);
277 /* By default prepare 64bit headers */
278 ret = crash_prepare_elf64_headers(cmem,
279 IS_ENABLED(CONFIG_X86_64), addr, sz);
284 * If a range matches backup region, adjust offset to backup
287 ehdr = (Elf64_Ehdr *)*addr;
288 phdr = (Elf64_Phdr *)(ehdr + 1);
289 for (i = 0; i < ehdr->e_phnum; phdr++, i++)
290 if (phdr->p_type == PT_LOAD &&
291 phdr->p_paddr == image->arch.backup_src_start &&
292 phdr->p_memsz == image->arch.backup_src_sz) {
293 phdr->p_offset = image->arch.backup_load_addr;
301 static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
303 unsigned int nr_e820_entries;
305 nr_e820_entries = params->e820_entries;
306 if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
309 memcpy(¶ms->e820_table[nr_e820_entries], entry,
310 sizeof(struct e820_entry));
311 params->e820_entries++;
315 static int memmap_entry_callback(struct resource *res, void *arg)
317 struct crash_memmap_data *cmd = arg;
318 struct boot_params *params = cmd->params;
319 struct e820_entry ei;
321 ei.addr = res->start;
322 ei.size = resource_size(res);
324 add_e820_entry(params, &ei);
329 static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
330 unsigned long long mstart,
331 unsigned long long mend)
333 unsigned long start, end;
336 cmem->ranges[0].start = mstart;
337 cmem->ranges[0].end = mend;
340 /* Exclude Backup region */
341 start = image->arch.backup_load_addr;
342 end = start + image->arch.backup_src_sz - 1;
343 ret = crash_exclude_mem_range(cmem, start, end);
347 /* Exclude elf header region */
348 start = image->arch.elf_load_addr;
349 end = start + image->arch.elf_headers_sz - 1;
350 return crash_exclude_mem_range(cmem, start, end);
353 /* Prepare memory map for crash dump kernel */
354 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
358 struct e820_entry ei;
359 struct crash_memmap_data cmd;
360 struct crash_mem *cmem;
362 cmem = vzalloc(sizeof(struct crash_mem));
366 memset(&cmd, 0, sizeof(struct crash_memmap_data));
369 /* Add first 640K segment */
370 ei.addr = image->arch.backup_src_start;
371 ei.size = image->arch.backup_src_sz;
372 ei.type = E820_TYPE_RAM;
373 add_e820_entry(params, &ei);
375 /* Add ACPI tables */
376 cmd.type = E820_TYPE_ACPI;
377 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
378 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
379 memmap_entry_callback);
381 /* Add ACPI Non-volatile Storage */
382 cmd.type = E820_TYPE_NVS;
383 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
384 memmap_entry_callback);
386 /* Add crashk_low_res region */
387 if (crashk_low_res.end) {
388 ei.addr = crashk_low_res.start;
389 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
390 ei.type = E820_TYPE_RAM;
391 add_e820_entry(params, &ei);
394 /* Exclude some ranges from crashk_res and add rest to memmap */
395 ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
400 for (i = 0; i < cmem->nr_ranges; i++) {
401 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
403 /* If entry is less than a page, skip it */
404 if (ei.size < PAGE_SIZE)
406 ei.addr = cmem->ranges[i].start;
407 ei.type = E820_TYPE_RAM;
408 add_e820_entry(params, &ei);
416 static int determine_backup_region(struct resource *res, void *arg)
418 struct kimage *image = arg;
420 image->arch.backup_src_start = res->start;
421 image->arch.backup_src_sz = resource_size(res);
423 /* Expecting only one range for backup region */
427 int crash_load_segments(struct kimage *image)
430 struct kexec_buf kbuf = { .image = image, .buf_min = 0,
431 .buf_max = ULONG_MAX, .top_down = false };
434 * Determine and load a segment for backup area. First 640K RAM
435 * region is backup source
438 ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
439 image, determine_backup_region);
441 /* Zero or postive return values are ok */
445 /* Add backup segment. */
446 if (image->arch.backup_src_sz) {
447 kbuf.buffer = &crash_zero_bytes;
448 kbuf.bufsz = sizeof(crash_zero_bytes);
449 kbuf.memsz = image->arch.backup_src_sz;
450 kbuf.buf_align = PAGE_SIZE;
452 * Ideally there is no source for backup segment. This is
453 * copied in purgatory after crash. Just add a zero filled
454 * segment for now to make sure checksum logic works fine.
456 ret = kexec_add_buffer(&kbuf);
459 image->arch.backup_load_addr = kbuf.mem;
460 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
461 image->arch.backup_load_addr,
462 image->arch.backup_src_start, kbuf.memsz);
465 /* Prepare elf headers and add a segment */
466 ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
470 image->arch.elf_headers = kbuf.buffer;
471 image->arch.elf_headers_sz = kbuf.bufsz;
473 kbuf.memsz = kbuf.bufsz;
474 kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
475 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
476 ret = kexec_add_buffer(&kbuf);
478 vfree((void *)image->arch.elf_headers);
481 image->arch.elf_load_addr = kbuf.mem;
482 pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
483 image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
487 #endif /* CONFIG_KEXEC_FILE */