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);
59 unsigned long crash_zero_bytes;
61 static inline void cpu_crash_vmclear_loaded_vmcss(void)
63 crash_vmclear_fn *do_vmclear_operation = NULL;
66 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
67 if (do_vmclear_operation)
68 do_vmclear_operation();
72 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
74 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
77 struct pt_regs fixed_regs;
79 if (!user_mode(regs)) {
80 crash_fixup_ss_esp(&fixed_regs, regs);
84 crash_save_cpu(regs, cpu);
87 * VMCLEAR VMCSs loaded on all cpus if needed.
89 cpu_crash_vmclear_loaded_vmcss();
91 /* Disable VMX or SVM if needed.
93 * We need to disable virtualization on all CPUs.
94 * Having VMX or SVM enabled on any CPU may break rebooting
95 * after the kdump kernel has finished its task.
97 cpu_emergency_vmxoff();
98 cpu_emergency_svm_disable();
101 * Disable Intel PT to stop its logging
103 cpu_emergency_stop_pt();
105 disable_local_APIC();
108 void kdump_nmi_shootdown_cpus(void)
110 nmi_shootdown_cpus(kdump_nmi_callback);
112 disable_local_APIC();
115 /* Override the weak function in kernel/panic.c */
116 void crash_smp_send_stop(void)
118 static int cpus_stopped;
123 if (smp_ops.crash_stop_other_cpus)
124 smp_ops.crash_stop_other_cpus();
132 void crash_smp_send_stop(void)
134 /* There are no cpus to shootdown */
138 void native_machine_crash_shutdown(struct pt_regs *regs)
140 /* This function is only called after the system
141 * has panicked or is otherwise in a critical state.
142 * The minimum amount of code to allow a kexec'd kernel
143 * to run successfully needs to happen here.
145 * In practice this means shooting down the other cpus in
148 /* The kernel is broken so disable interrupts */
151 crash_smp_send_stop();
154 * VMCLEAR VMCSs loaded on this cpu if needed.
156 cpu_crash_vmclear_loaded_vmcss();
158 /* Booting kdump kernel with VMX or SVM enabled won't work,
159 * because (among other limitations) we can't disable paging
160 * with the virt flags.
162 cpu_emergency_vmxoff();
163 cpu_emergency_svm_disable();
166 * Disable Intel PT to stop its logging
168 cpu_emergency_stop_pt();
170 #ifdef CONFIG_X86_IO_APIC
171 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
176 restore_boot_irq_mode();
177 #ifdef CONFIG_HPET_TIMER
180 crash_save_cpu(regs, safe_smp_processor_id());
183 #ifdef CONFIG_KEXEC_FILE
184 static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
186 unsigned int *nr_ranges = arg;
192 /* Gather all the required information to prepare elf headers for ram regions */
193 static struct crash_mem *fill_up_crash_elf_data(void)
195 unsigned int nr_ranges = 0;
196 struct crash_mem *cmem;
198 walk_system_ram_res(0, -1, &nr_ranges,
199 get_nr_ram_ranges_callback);
204 * Exclusion of crash region and/or crashk_low_res may cause
205 * another range split. So add extra two slots here.
208 cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
212 cmem->max_nr_ranges = nr_ranges;
219 * Look for any unwanted ranges between mstart, mend and remove them. This
220 * might lead to split and split ranges are put in cmem->ranges[] array
222 static int elf_header_exclude_ranges(struct crash_mem *cmem)
226 /* Exclude crashkernel region */
227 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
231 if (crashk_low_res.end) {
232 ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
241 static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
243 struct crash_mem *cmem = arg;
245 cmem->ranges[cmem->nr_ranges].start = res->start;
246 cmem->ranges[cmem->nr_ranges].end = res->end;
252 /* Prepare elf headers. Return addr and size */
253 static int prepare_elf_headers(struct kimage *image, void **addr,
256 struct crash_mem *cmem;
261 cmem = fill_up_crash_elf_data();
265 ret = walk_system_ram_res(0, -1, cmem,
266 prepare_elf64_ram_headers_callback);
270 /* Exclude unwanted mem ranges */
271 ret = elf_header_exclude_ranges(cmem);
275 /* By default prepare 64bit headers */
276 ret = crash_prepare_elf64_headers(cmem,
277 IS_ENABLED(CONFIG_X86_64), addr, sz);
282 * If a range matches backup region, adjust offset to backup
285 ehdr = (Elf64_Ehdr *)*addr;
286 phdr = (Elf64_Phdr *)(ehdr + 1);
287 for (i = 0; i < ehdr->e_phnum; phdr++, i++)
288 if (phdr->p_type == PT_LOAD &&
289 phdr->p_paddr == image->arch.backup_src_start &&
290 phdr->p_memsz == image->arch.backup_src_sz) {
291 phdr->p_offset = image->arch.backup_load_addr;
299 static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
301 unsigned int nr_e820_entries;
303 nr_e820_entries = params->e820_entries;
304 if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
307 memcpy(¶ms->e820_table[nr_e820_entries], entry,
308 sizeof(struct e820_entry));
309 params->e820_entries++;
313 static int memmap_entry_callback(struct resource *res, void *arg)
315 struct crash_memmap_data *cmd = arg;
316 struct boot_params *params = cmd->params;
317 struct e820_entry ei;
319 ei.addr = res->start;
320 ei.size = resource_size(res);
322 add_e820_entry(params, &ei);
327 static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
328 unsigned long long mstart,
329 unsigned long long mend)
331 unsigned long start, end;
334 cmem->ranges[0].start = mstart;
335 cmem->ranges[0].end = mend;
338 /* Exclude Backup region */
339 start = image->arch.backup_load_addr;
340 end = start + image->arch.backup_src_sz - 1;
341 ret = crash_exclude_mem_range(cmem, start, end);
345 /* Exclude elf header region */
346 start = image->arch.elf_load_addr;
347 end = start + image->arch.elf_headers_sz - 1;
348 return crash_exclude_mem_range(cmem, start, end);
351 /* Prepare memory map for crash dump kernel */
352 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
356 struct e820_entry ei;
357 struct crash_memmap_data cmd;
358 struct crash_mem *cmem;
360 cmem = vzalloc(sizeof(struct crash_mem));
364 memset(&cmd, 0, sizeof(struct crash_memmap_data));
367 /* Add first 640K segment */
368 ei.addr = image->arch.backup_src_start;
369 ei.size = image->arch.backup_src_sz;
370 ei.type = E820_TYPE_RAM;
371 add_e820_entry(params, &ei);
373 /* Add ACPI tables */
374 cmd.type = E820_TYPE_ACPI;
375 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
376 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
377 memmap_entry_callback);
379 /* Add ACPI Non-volatile Storage */
380 cmd.type = E820_TYPE_NVS;
381 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
382 memmap_entry_callback);
384 /* Add crashk_low_res region */
385 if (crashk_low_res.end) {
386 ei.addr = crashk_low_res.start;
387 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
388 ei.type = E820_TYPE_RAM;
389 add_e820_entry(params, &ei);
392 /* Exclude some ranges from crashk_res and add rest to memmap */
393 ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
398 for (i = 0; i < cmem->nr_ranges; i++) {
399 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
401 /* If entry is less than a page, skip it */
402 if (ei.size < PAGE_SIZE)
404 ei.addr = cmem->ranges[i].start;
405 ei.type = E820_TYPE_RAM;
406 add_e820_entry(params, &ei);
414 static int determine_backup_region(struct resource *res, void *arg)
416 struct kimage *image = arg;
418 image->arch.backup_src_start = res->start;
419 image->arch.backup_src_sz = resource_size(res);
421 /* Expecting only one range for backup region */
425 int crash_load_segments(struct kimage *image)
428 struct kexec_buf kbuf = { .image = image, .buf_min = 0,
429 .buf_max = ULONG_MAX, .top_down = false };
432 * Determine and load a segment for backup area. First 640K RAM
433 * region is backup source
436 ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
437 image, determine_backup_region);
439 /* Zero or postive return values are ok */
443 /* Add backup segment. */
444 if (image->arch.backup_src_sz) {
445 kbuf.buffer = &crash_zero_bytes;
446 kbuf.bufsz = sizeof(crash_zero_bytes);
447 kbuf.memsz = image->arch.backup_src_sz;
448 kbuf.buf_align = PAGE_SIZE;
450 * Ideally there is no source for backup segment. This is
451 * copied in purgatory after crash. Just add a zero filled
452 * segment for now to make sure checksum logic works fine.
454 ret = kexec_add_buffer(&kbuf);
457 image->arch.backup_load_addr = kbuf.mem;
458 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
459 image->arch.backup_load_addr,
460 image->arch.backup_src_start, kbuf.memsz);
463 /* Prepare elf headers and add a segment */
464 ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
468 image->arch.elf_headers = kbuf.buffer;
469 image->arch.elf_headers_sz = kbuf.bufsz;
471 kbuf.memsz = kbuf.bufsz;
472 kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
473 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
474 ret = kexec_add_buffer(&kbuf);
476 vfree((void *)image->arch.elf_headers);
479 image->arch.elf_load_addr = kbuf.mem;
480 pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
481 image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
485 #endif /* CONFIG_KEXEC_FILE */