2 * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
4 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
6 * Copyright (C) IBM Corporation, 2004. All rights reserved.
7 * Copyright (C) Red Hat Inc., 2014. All rights reserved.
9 * Vivek Goyal <vgoyal@redhat.com>
13 #define pr_fmt(fmt) "kexec: " fmt
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>
27 #include <asm/processor.h>
28 #include <asm/hardirq.h>
30 #include <asm/hw_irq.h>
32 #include <asm/io_apic.h>
34 #include <linux/kdebug.h>
36 #include <asm/reboot.h>
37 #include <asm/virtext.h>
38 #include <asm/intel_pt.h>
40 /* Alignment required for elf header segment */
41 #define ELF_CORE_HEADER_ALIGN 4096
43 /* This primarily represents number of split ranges due to exclusion */
44 #define CRASH_MAX_RANGES 16
46 struct crash_mem_range {
51 unsigned int nr_ranges;
52 struct crash_mem_range ranges[CRASH_MAX_RANGES];
55 /* Misc data about ram ranges needed to prepare elf headers */
56 struct crash_elf_data {
59 * Total number of ram ranges we have after various adjustments for
60 * crash reserved region, etc.
62 unsigned int max_nr_ranges;
64 /* Pointer to elf header */
66 /* Pointer to next phdr */
71 /* Used while preparing memory map entries for second kernel */
72 struct crash_memmap_data {
73 struct boot_params *params;
79 * This is used to VMCLEAR all VMCSs loaded on the
80 * processor. And when loading kvm_intel module, the
81 * callback function pointer will be assigned.
85 crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
86 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
87 unsigned long crash_zero_bytes;
89 static inline void cpu_crash_vmclear_loaded_vmcss(void)
91 crash_vmclear_fn *do_vmclear_operation = NULL;
94 do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
95 if (do_vmclear_operation)
96 do_vmclear_operation();
100 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
102 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
105 struct pt_regs fixed_regs;
107 if (!user_mode(regs)) {
108 crash_fixup_ss_esp(&fixed_regs, regs);
112 crash_save_cpu(regs, cpu);
115 * VMCLEAR VMCSs loaded on all cpus if needed.
117 cpu_crash_vmclear_loaded_vmcss();
119 /* Disable VMX or SVM if needed.
121 * We need to disable virtualization on all CPUs.
122 * Having VMX or SVM enabled on any CPU may break rebooting
123 * after the kdump kernel has finished its task.
125 cpu_emergency_vmxoff();
126 cpu_emergency_svm_disable();
129 * Disable Intel PT to stop its logging
131 cpu_emergency_stop_pt();
133 disable_local_APIC();
136 void kdump_nmi_shootdown_cpus(void)
138 nmi_shootdown_cpus(kdump_nmi_callback);
140 disable_local_APIC();
143 /* Override the weak function in kernel/panic.c */
144 void crash_smp_send_stop(void)
146 static int cpus_stopped;
151 if (smp_ops.crash_stop_other_cpus)
152 smp_ops.crash_stop_other_cpus();
160 void crash_smp_send_stop(void)
162 /* There are no cpus to shootdown */
166 void native_machine_crash_shutdown(struct pt_regs *regs)
168 /* This function is only called after the system
169 * has panicked or is otherwise in a critical state.
170 * The minimum amount of code to allow a kexec'd kernel
171 * to run successfully needs to happen here.
173 * In practice this means shooting down the other cpus in
176 /* The kernel is broken so disable interrupts */
179 crash_smp_send_stop();
182 * VMCLEAR VMCSs loaded on this cpu if needed.
184 cpu_crash_vmclear_loaded_vmcss();
186 /* Booting kdump kernel with VMX or SVM enabled won't work,
187 * because (among other limitations) we can't disable paging
188 * with the virt flags.
190 cpu_emergency_vmxoff();
191 cpu_emergency_svm_disable();
194 * Disable Intel PT to stop its logging
196 cpu_emergency_stop_pt();
198 #ifdef CONFIG_X86_IO_APIC
199 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
204 #ifdef CONFIG_HPET_TIMER
207 crash_save_cpu(regs, safe_smp_processor_id());
210 #ifdef CONFIG_KEXEC_FILE
211 static int get_nr_ram_ranges_callback(u64 start, u64 end, void *arg)
213 unsigned int *nr_ranges = arg;
220 /* Gather all the required information to prepare elf headers for ram regions */
221 static void fill_up_crash_elf_data(struct crash_elf_data *ced,
222 struct kimage *image)
224 unsigned int nr_ranges = 0;
228 walk_system_ram_res(0, -1, &nr_ranges,
229 get_nr_ram_ranges_callback);
231 ced->max_nr_ranges = nr_ranges;
233 /* Exclusion of crash region could split memory ranges */
234 ced->max_nr_ranges++;
236 /* If crashk_low_res is not 0, another range split possible */
237 if (crashk_low_res.end)
238 ced->max_nr_ranges++;
241 static int exclude_mem_range(struct crash_mem *mem,
242 unsigned long long mstart, unsigned long long mend)
245 unsigned long long start, end;
246 struct crash_mem_range temp_range = {0, 0};
248 for (i = 0; i < mem->nr_ranges; i++) {
249 start = mem->ranges[i].start;
250 end = mem->ranges[i].end;
252 if (mstart > end || mend < start)
255 /* Truncate any area outside of range */
261 /* Found completely overlapping range */
262 if (mstart == start && mend == end) {
263 mem->ranges[i].start = 0;
264 mem->ranges[i].end = 0;
265 if (i < mem->nr_ranges - 1) {
266 /* Shift rest of the ranges to left */
267 for (j = i; j < mem->nr_ranges - 1; j++) {
268 mem->ranges[j].start =
269 mem->ranges[j+1].start;
271 mem->ranges[j+1].end;
278 if (mstart > start && mend < end) {
279 /* Split original range */
280 mem->ranges[i].end = mstart - 1;
281 temp_range.start = mend + 1;
282 temp_range.end = end;
283 } else if (mstart != start)
284 mem->ranges[i].end = mstart - 1;
286 mem->ranges[i].start = mend + 1;
290 /* If a split happend, add the split to array */
295 if (i == CRASH_MAX_RANGES - 1) {
296 pr_err("Too many crash ranges after split\n");
300 /* Location where new range should go */
302 if (j < mem->nr_ranges) {
303 /* Move over all ranges one slot towards the end */
304 for (i = mem->nr_ranges - 1; i >= j; i--)
305 mem->ranges[i + 1] = mem->ranges[i];
308 mem->ranges[j].start = temp_range.start;
309 mem->ranges[j].end = temp_range.end;
315 * Look for any unwanted ranges between mstart, mend and remove them. This
316 * might lead to split and split ranges are put in ced->mem.ranges[] array
318 static int elf_header_exclude_ranges(struct crash_elf_data *ced,
319 unsigned long long mstart, unsigned long long mend)
321 struct crash_mem *cmem = &ced->mem;
324 memset(cmem->ranges, 0, sizeof(cmem->ranges));
326 cmem->ranges[0].start = mstart;
327 cmem->ranges[0].end = mend;
330 /* Exclude crashkernel region */
331 ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
335 if (crashk_low_res.end) {
336 ret = exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
344 static int prepare_elf64_ram_headers_callback(u64 start, u64 end, void *arg)
346 struct crash_elf_data *ced = arg;
349 unsigned long mstart, mend;
350 struct kimage *image = ced->image;
351 struct crash_mem *cmem;
356 /* Exclude unwanted mem ranges */
357 ret = elf_header_exclude_ranges(ced, start, end);
361 /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
364 for (i = 0; i < cmem->nr_ranges; i++) {
365 mstart = cmem->ranges[i].start;
366 mend = cmem->ranges[i].end;
369 ced->bufp += sizeof(Elf64_Phdr);
371 phdr->p_type = PT_LOAD;
372 phdr->p_flags = PF_R|PF_W|PF_X;
373 phdr->p_offset = mstart;
376 * If a range matches backup region, adjust offset to backup
379 if (mstart == image->arch.backup_src_start &&
380 (mend - mstart + 1) == image->arch.backup_src_sz)
381 phdr->p_offset = image->arch.backup_load_addr;
383 phdr->p_paddr = mstart;
384 phdr->p_vaddr = (unsigned long long) __va(mstart);
385 phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
388 pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
389 phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
390 ehdr->e_phnum, phdr->p_offset);
396 static int prepare_elf64_headers(struct crash_elf_data *ced,
397 void **addr, unsigned long *sz)
401 unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
402 unsigned char *buf, *bufp;
404 unsigned long long notes_addr;
407 /* extra phdr for vmcoreinfo elf note */
408 nr_phdr = nr_cpus + 1;
409 nr_phdr += ced->max_nr_ranges;
412 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
413 * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
414 * I think this is required by tools like gdb. So same physical
415 * memory will be mapped in two elf headers. One will contain kernel
416 * text virtual addresses and other will have __va(physical) addresses.
420 elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
421 elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
423 buf = vzalloc(elf_sz);
428 ehdr = (Elf64_Ehdr *)bufp;
429 bufp += sizeof(Elf64_Ehdr);
430 memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
431 ehdr->e_ident[EI_CLASS] = ELFCLASS64;
432 ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
433 ehdr->e_ident[EI_VERSION] = EV_CURRENT;
434 ehdr->e_ident[EI_OSABI] = ELF_OSABI;
435 memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
436 ehdr->e_type = ET_CORE;
437 ehdr->e_machine = ELF_ARCH;
438 ehdr->e_version = EV_CURRENT;
439 ehdr->e_phoff = sizeof(Elf64_Ehdr);
440 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
441 ehdr->e_phentsize = sizeof(Elf64_Phdr);
443 /* Prepare one phdr of type PT_NOTE for each present cpu */
444 for_each_present_cpu(cpu) {
445 phdr = (Elf64_Phdr *)bufp;
446 bufp += sizeof(Elf64_Phdr);
447 phdr->p_type = PT_NOTE;
448 notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
449 phdr->p_offset = phdr->p_paddr = notes_addr;
450 phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
454 /* Prepare one PT_NOTE header for vmcoreinfo */
455 phdr = (Elf64_Phdr *)bufp;
456 bufp += sizeof(Elf64_Phdr);
457 phdr->p_type = PT_NOTE;
458 phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
459 phdr->p_filesz = phdr->p_memsz = sizeof(vmcoreinfo_note);
463 /* Prepare PT_LOAD type program header for kernel text region */
464 phdr = (Elf64_Phdr *)bufp;
465 bufp += sizeof(Elf64_Phdr);
466 phdr->p_type = PT_LOAD;
467 phdr->p_flags = PF_R|PF_W|PF_X;
468 phdr->p_vaddr = (Elf64_Addr)_text;
469 phdr->p_filesz = phdr->p_memsz = _end - _text;
470 phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
474 /* Prepare PT_LOAD headers for system ram chunks. */
477 ret = walk_system_ram_res(0, -1, ced,
478 prepare_elf64_ram_headers_callback);
487 /* Prepare elf headers. Return addr and size */
488 static int prepare_elf_headers(struct kimage *image, void **addr,
491 struct crash_elf_data *ced;
494 ced = kzalloc(sizeof(*ced), GFP_KERNEL);
498 fill_up_crash_elf_data(ced, image);
500 /* By default prepare 64bit headers */
501 ret = prepare_elf64_headers(ced, addr, sz);
506 static int add_e820_entry(struct boot_params *params, struct e820entry *entry)
508 unsigned int nr_e820_entries;
510 nr_e820_entries = params->e820_entries;
511 if (nr_e820_entries >= E820MAX)
514 memcpy(¶ms->e820_map[nr_e820_entries], entry,
515 sizeof(struct e820entry));
516 params->e820_entries++;
520 static int memmap_entry_callback(u64 start, u64 end, void *arg)
522 struct crash_memmap_data *cmd = arg;
523 struct boot_params *params = cmd->params;
527 ei.size = end - start + 1;
529 add_e820_entry(params, &ei);
534 static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
535 unsigned long long mstart,
536 unsigned long long mend)
538 unsigned long start, end;
541 cmem->ranges[0].start = mstart;
542 cmem->ranges[0].end = mend;
545 /* Exclude Backup region */
546 start = image->arch.backup_load_addr;
547 end = start + image->arch.backup_src_sz - 1;
548 ret = exclude_mem_range(cmem, start, end);
552 /* Exclude elf header region */
553 start = image->arch.elf_load_addr;
554 end = start + image->arch.elf_headers_sz - 1;
555 return exclude_mem_range(cmem, start, end);
558 /* Prepare memory map for crash dump kernel */
559 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
564 struct crash_memmap_data cmd;
565 struct crash_mem *cmem;
567 cmem = vzalloc(sizeof(struct crash_mem));
571 memset(&cmd, 0, sizeof(struct crash_memmap_data));
574 /* Add first 640K segment */
575 ei.addr = image->arch.backup_src_start;
576 ei.size = image->arch.backup_src_sz;
578 add_e820_entry(params, &ei);
580 /* Add ACPI tables */
581 cmd.type = E820_ACPI;
582 flags = IORESOURCE_MEM | IORESOURCE_BUSY;
583 walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
584 memmap_entry_callback);
586 /* Add ACPI Non-volatile Storage */
588 walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
589 memmap_entry_callback);
591 /* Add crashk_low_res region */
592 if (crashk_low_res.end) {
593 ei.addr = crashk_low_res.start;
594 ei.size = crashk_low_res.end - crashk_low_res.start + 1;
596 add_e820_entry(params, &ei);
599 /* Exclude some ranges from crashk_res and add rest to memmap */
600 ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
605 for (i = 0; i < cmem->nr_ranges; i++) {
606 ei.size = cmem->ranges[i].end - cmem->ranges[i].start + 1;
608 /* If entry is less than a page, skip it */
609 if (ei.size < PAGE_SIZE)
611 ei.addr = cmem->ranges[i].start;
613 add_e820_entry(params, &ei);
621 static int determine_backup_region(u64 start, u64 end, void *arg)
623 struct kimage *image = arg;
625 image->arch.backup_src_start = start;
626 image->arch.backup_src_sz = end - start + 1;
628 /* Expecting only one range for backup region */
632 int crash_load_segments(struct kimage *image)
634 unsigned long src_start, src_sz, elf_sz;
639 * Determine and load a segment for backup area. First 640K RAM
640 * region is backup source
643 ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
644 image, determine_backup_region);
646 /* Zero or postive return values are ok */
650 src_start = image->arch.backup_src_start;
651 src_sz = image->arch.backup_src_sz;
653 /* Add backup segment. */
656 * Ideally there is no source for backup segment. This is
657 * copied in purgatory after crash. Just add a zero filled
658 * segment for now to make sure checksum logic works fine.
660 ret = kexec_add_buffer(image, (char *)&crash_zero_bytes,
661 sizeof(crash_zero_bytes), src_sz,
663 &image->arch.backup_load_addr);
666 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
667 image->arch.backup_load_addr, src_start, src_sz);
670 /* Prepare elf headers and add a segment */
671 ret = prepare_elf_headers(image, &elf_addr, &elf_sz);
675 image->arch.elf_headers = elf_addr;
676 image->arch.elf_headers_sz = elf_sz;
678 ret = kexec_add_buffer(image, (char *)elf_addr, elf_sz, elf_sz,
679 ELF_CORE_HEADER_ALIGN, 0, -1, 0,
680 &image->arch.elf_load_addr);
682 vfree((void *)image->arch.elf_headers);
685 pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
686 image->arch.elf_load_addr, elf_sz, elf_sz);
690 #endif /* CONFIG_KEXEC_FILE */