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/module.h>
24 #include <linux/slab.h>
26 #include <asm/processor.h>
27 #include <asm/hardirq.h>
29 #include <asm/hw_irq.h>
31 #include <asm/io_apic.h>
33 #include <linux/kdebug.h>
35 #include <asm/reboot.h>
36 #include <asm/virtext.h>
38 /* Alignment required for elf header segment */
39 #define ELF_CORE_HEADER_ALIGN 4096
41 /* This primarily represents number of split ranges due to exclusion */
42 #define CRASH_MAX_RANGES 16
44 struct crash_mem_range
{
49 unsigned int nr_ranges
;
50 struct crash_mem_range ranges
[CRASH_MAX_RANGES
];
53 /* Misc data about ram ranges needed to prepare elf headers */
54 struct crash_elf_data
{
57 * Total number of ram ranges we have after various adjustments for
58 * GART, crash reserved region etc.
60 unsigned int max_nr_ranges
;
61 unsigned long gart_start
, gart_end
;
63 /* Pointer to elf header */
65 /* Pointer to next phdr */
70 /* Used while preparing memory map entries for second kernel */
71 struct crash_memmap_data
{
72 struct boot_params
*params
;
80 * This is used to VMCLEAR all VMCSs loaded on the
81 * processor. And when loading kvm_intel module, the
82 * callback function pointer will be assigned.
86 crash_vmclear_fn __rcu
*crash_vmclear_loaded_vmcss
= NULL
;
87 EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss
);
88 unsigned long crash_zero_bytes
;
90 static inline void cpu_crash_vmclear_loaded_vmcss(void)
92 crash_vmclear_fn
*do_vmclear_operation
= NULL
;
95 do_vmclear_operation
= rcu_dereference(crash_vmclear_loaded_vmcss
);
96 if (do_vmclear_operation
)
97 do_vmclear_operation();
101 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
103 static void kdump_nmi_callback(int cpu
, struct pt_regs
*regs
)
106 struct pt_regs fixed_regs
;
108 if (!user_mode_vm(regs
)) {
109 crash_fixup_ss_esp(&fixed_regs
, regs
);
113 crash_save_cpu(regs
, cpu
);
116 * VMCLEAR VMCSs loaded on all cpus if needed.
118 cpu_crash_vmclear_loaded_vmcss();
120 /* Disable VMX or SVM if needed.
122 * We need to disable virtualization on all CPUs.
123 * Having VMX or SVM enabled on any CPU may break rebooting
124 * after the kdump kernel has finished its task.
126 cpu_emergency_vmxoff();
127 cpu_emergency_svm_disable();
129 disable_local_APIC();
132 static void kdump_nmi_shootdown_cpus(void)
135 nmi_shootdown_cpus(kdump_nmi_callback
);
137 disable_local_APIC();
141 static void kdump_nmi_shootdown_cpus(void)
143 /* There are no cpus to shootdown */
147 void native_machine_crash_shutdown(struct pt_regs
*regs
)
149 /* This function is only called after the system
150 * has panicked or is otherwise in a critical state.
151 * The minimum amount of code to allow a kexec'd kernel
152 * to run successfully needs to happen here.
154 * In practice this means shooting down the other cpus in
157 /* The kernel is broken so disable interrupts */
160 kdump_nmi_shootdown_cpus();
163 * VMCLEAR VMCSs loaded on this cpu if needed.
165 cpu_crash_vmclear_loaded_vmcss();
167 /* Booting kdump kernel with VMX or SVM enabled won't work,
168 * because (among other limitations) we can't disable paging
169 * with the virt flags.
171 cpu_emergency_vmxoff();
172 cpu_emergency_svm_disable();
174 #ifdef CONFIG_X86_IO_APIC
175 /* Prevent crash_kexec() from deadlocking on ioapic_lock. */
180 #ifdef CONFIG_HPET_TIMER
183 crash_save_cpu(regs
, safe_smp_processor_id());
186 #ifdef CONFIG_KEXEC_FILE
187 static int get_nr_ram_ranges_callback(unsigned long start_pfn
,
188 unsigned long nr_pfn
, void *arg
)
190 int *nr_ranges
= arg
;
196 static int get_gart_ranges_callback(u64 start
, u64 end
, void *arg
)
198 struct crash_elf_data
*ced
= arg
;
200 ced
->gart_start
= start
;
203 /* Not expecting more than 1 gart aperture */
208 /* Gather all the required information to prepare elf headers for ram regions */
209 static void fill_up_crash_elf_data(struct crash_elf_data
*ced
,
210 struct kimage
*image
)
212 unsigned int nr_ranges
= 0;
216 walk_system_ram_range(0, -1, &nr_ranges
,
217 get_nr_ram_ranges_callback
);
219 ced
->max_nr_ranges
= nr_ranges
;
222 * We don't create ELF headers for GART aperture as an attempt
223 * to dump this memory in second kernel leads to hang/crash.
224 * If gart aperture is present, one needs to exclude that region
225 * and that could lead to need of extra phdr.
227 walk_iomem_res("GART", IORESOURCE_MEM
, 0, -1,
228 ced
, get_gart_ranges_callback
);
231 * If we have gart region, excluding that could potentially split
232 * a memory range, resulting in extra header. Account for that.
235 ced
->max_nr_ranges
++;
237 /* Exclusion of crash region could split memory ranges */
238 ced
->max_nr_ranges
++;
240 /* If crashk_low_res is not 0, another range split possible */
241 if (crashk_low_res
.end
)
242 ced
->max_nr_ranges
++;
245 static int exclude_mem_range(struct crash_mem
*mem
,
246 unsigned long long mstart
, unsigned long long mend
)
249 unsigned long long start
, end
;
250 struct crash_mem_range temp_range
= {0, 0};
252 for (i
= 0; i
< mem
->nr_ranges
; i
++) {
253 start
= mem
->ranges
[i
].start
;
254 end
= mem
->ranges
[i
].end
;
256 if (mstart
> end
|| mend
< start
)
259 /* Truncate any area outside of range */
265 /* Found completely overlapping range */
266 if (mstart
== start
&& mend
== end
) {
267 mem
->ranges
[i
].start
= 0;
268 mem
->ranges
[i
].end
= 0;
269 if (i
< mem
->nr_ranges
- 1) {
270 /* Shift rest of the ranges to left */
271 for (j
= i
; j
< mem
->nr_ranges
- 1; j
++) {
272 mem
->ranges
[j
].start
=
273 mem
->ranges
[j
+1].start
;
275 mem
->ranges
[j
+1].end
;
282 if (mstart
> start
&& mend
< end
) {
283 /* Split original range */
284 mem
->ranges
[i
].end
= mstart
- 1;
285 temp_range
.start
= mend
+ 1;
286 temp_range
.end
= end
;
287 } else if (mstart
!= start
)
288 mem
->ranges
[i
].end
= mstart
- 1;
290 mem
->ranges
[i
].start
= mend
+ 1;
294 /* If a split happend, add the split to array */
299 if (i
== CRASH_MAX_RANGES
- 1) {
300 pr_err("Too many crash ranges after split\n");
304 /* Location where new range should go */
306 if (j
< mem
->nr_ranges
) {
307 /* Move over all ranges one slot towards the end */
308 for (i
= mem
->nr_ranges
- 1; i
>= j
; i
--)
309 mem
->ranges
[i
+ 1] = mem
->ranges
[i
];
312 mem
->ranges
[j
].start
= temp_range
.start
;
313 mem
->ranges
[j
].end
= temp_range
.end
;
319 * Look for any unwanted ranges between mstart, mend and remove them. This
320 * might lead to split and split ranges are put in ced->mem.ranges[] array
322 static int elf_header_exclude_ranges(struct crash_elf_data
*ced
,
323 unsigned long long mstart
, unsigned long long mend
)
325 struct crash_mem
*cmem
= &ced
->mem
;
328 memset(cmem
->ranges
, 0, sizeof(cmem
->ranges
));
330 cmem
->ranges
[0].start
= mstart
;
331 cmem
->ranges
[0].end
= mend
;
334 /* Exclude crashkernel region */
335 ret
= exclude_mem_range(cmem
, crashk_res
.start
, crashk_res
.end
);
339 if (crashk_low_res
.end
) {
340 ret
= exclude_mem_range(cmem
, crashk_low_res
.start
, crashk_low_res
.end
);
345 /* Exclude GART region */
347 ret
= exclude_mem_range(cmem
, ced
->gart_start
, ced
->gart_end
);
355 static int prepare_elf64_ram_headers_callback(u64 start
, u64 end
, void *arg
)
357 struct crash_elf_data
*ced
= arg
;
360 unsigned long mstart
, mend
;
361 struct kimage
*image
= ced
->image
;
362 struct crash_mem
*cmem
;
367 /* Exclude unwanted mem ranges */
368 ret
= elf_header_exclude_ranges(ced
, start
, end
);
372 /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */
375 for (i
= 0; i
< cmem
->nr_ranges
; i
++) {
376 mstart
= cmem
->ranges
[i
].start
;
377 mend
= cmem
->ranges
[i
].end
;
380 ced
->bufp
+= sizeof(Elf64_Phdr
);
382 phdr
->p_type
= PT_LOAD
;
383 phdr
->p_flags
= PF_R
|PF_W
|PF_X
;
384 phdr
->p_offset
= mstart
;
387 * If a range matches backup region, adjust offset to backup
390 if (mstart
== image
->arch
.backup_src_start
&&
391 (mend
- mstart
+ 1) == image
->arch
.backup_src_sz
)
392 phdr
->p_offset
= image
->arch
.backup_load_addr
;
394 phdr
->p_paddr
= mstart
;
395 phdr
->p_vaddr
= (unsigned long long) __va(mstart
);
396 phdr
->p_filesz
= phdr
->p_memsz
= mend
- mstart
+ 1;
399 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",
400 phdr
, phdr
->p_vaddr
, phdr
->p_paddr
, phdr
->p_filesz
,
401 ehdr
->e_phnum
, phdr
->p_offset
);
407 static int prepare_elf64_headers(struct crash_elf_data
*ced
,
408 void **addr
, unsigned long *sz
)
412 unsigned long nr_cpus
= num_possible_cpus(), nr_phdr
, elf_sz
;
413 unsigned char *buf
, *bufp
;
415 unsigned long long notes_addr
;
418 /* extra phdr for vmcoreinfo elf note */
419 nr_phdr
= nr_cpus
+ 1;
420 nr_phdr
+= ced
->max_nr_ranges
;
423 * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
424 * area on x86_64 (ffffffff80000000 - ffffffffa0000000).
425 * I think this is required by tools like gdb. So same physical
426 * memory will be mapped in two elf headers. One will contain kernel
427 * text virtual addresses and other will have __va(physical) addresses.
431 elf_sz
= sizeof(Elf64_Ehdr
) + nr_phdr
* sizeof(Elf64_Phdr
);
432 elf_sz
= ALIGN(elf_sz
, ELF_CORE_HEADER_ALIGN
);
434 buf
= vzalloc(elf_sz
);
439 ehdr
= (Elf64_Ehdr
*)bufp
;
440 bufp
+= sizeof(Elf64_Ehdr
);
441 memcpy(ehdr
->e_ident
, ELFMAG
, SELFMAG
);
442 ehdr
->e_ident
[EI_CLASS
] = ELFCLASS64
;
443 ehdr
->e_ident
[EI_DATA
] = ELFDATA2LSB
;
444 ehdr
->e_ident
[EI_VERSION
] = EV_CURRENT
;
445 ehdr
->e_ident
[EI_OSABI
] = ELF_OSABI
;
446 memset(ehdr
->e_ident
+ EI_PAD
, 0, EI_NIDENT
- EI_PAD
);
447 ehdr
->e_type
= ET_CORE
;
448 ehdr
->e_machine
= ELF_ARCH
;
449 ehdr
->e_version
= EV_CURRENT
;
450 ehdr
->e_phoff
= sizeof(Elf64_Ehdr
);
451 ehdr
->e_ehsize
= sizeof(Elf64_Ehdr
);
452 ehdr
->e_phentsize
= sizeof(Elf64_Phdr
);
454 /* Prepare one phdr of type PT_NOTE for each present cpu */
455 for_each_present_cpu(cpu
) {
456 phdr
= (Elf64_Phdr
*)bufp
;
457 bufp
+= sizeof(Elf64_Phdr
);
458 phdr
->p_type
= PT_NOTE
;
459 notes_addr
= per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes
, cpu
));
460 phdr
->p_offset
= phdr
->p_paddr
= notes_addr
;
461 phdr
->p_filesz
= phdr
->p_memsz
= sizeof(note_buf_t
);
465 /* Prepare one PT_NOTE header for vmcoreinfo */
466 phdr
= (Elf64_Phdr
*)bufp
;
467 bufp
+= sizeof(Elf64_Phdr
);
468 phdr
->p_type
= PT_NOTE
;
469 phdr
->p_offset
= phdr
->p_paddr
= paddr_vmcoreinfo_note();
470 phdr
->p_filesz
= phdr
->p_memsz
= sizeof(vmcoreinfo_note
);
474 /* Prepare PT_LOAD type program header for kernel text region */
475 phdr
= (Elf64_Phdr
*)bufp
;
476 bufp
+= sizeof(Elf64_Phdr
);
477 phdr
->p_type
= PT_LOAD
;
478 phdr
->p_flags
= PF_R
|PF_W
|PF_X
;
479 phdr
->p_vaddr
= (Elf64_Addr
)_text
;
480 phdr
->p_filesz
= phdr
->p_memsz
= _end
- _text
;
481 phdr
->p_offset
= phdr
->p_paddr
= __pa_symbol(_text
);
485 /* Prepare PT_LOAD headers for system ram chunks. */
488 ret
= walk_system_ram_res(0, -1, ced
,
489 prepare_elf64_ram_headers_callback
);
498 /* Prepare elf headers. Return addr and size */
499 static int prepare_elf_headers(struct kimage
*image
, void **addr
,
502 struct crash_elf_data
*ced
;
505 ced
= kzalloc(sizeof(*ced
), GFP_KERNEL
);
509 fill_up_crash_elf_data(ced
, image
);
511 /* By default prepare 64bit headers */
512 ret
= prepare_elf64_headers(ced
, addr
, sz
);
517 static int add_e820_entry(struct boot_params
*params
, struct e820entry
*entry
)
519 unsigned int nr_e820_entries
;
521 nr_e820_entries
= params
->e820_entries
;
522 if (nr_e820_entries
>= E820MAX
)
525 memcpy(¶ms
->e820_map
[nr_e820_entries
], entry
,
526 sizeof(struct e820entry
));
527 params
->e820_entries
++;
531 static int memmap_entry_callback(u64 start
, u64 end
, void *arg
)
533 struct crash_memmap_data
*cmd
= arg
;
534 struct boot_params
*params
= cmd
->params
;
538 ei
.size
= end
- start
+ 1;
540 add_e820_entry(params
, &ei
);
545 static int memmap_exclude_ranges(struct kimage
*image
, struct crash_mem
*cmem
,
546 unsigned long long mstart
,
547 unsigned long long mend
)
549 unsigned long start
, end
;
552 cmem
->ranges
[0].start
= mstart
;
553 cmem
->ranges
[0].end
= mend
;
556 /* Exclude Backup region */
557 start
= image
->arch
.backup_load_addr
;
558 end
= start
+ image
->arch
.backup_src_sz
- 1;
559 ret
= exclude_mem_range(cmem
, start
, end
);
563 /* Exclude elf header region */
564 start
= image
->arch
.elf_load_addr
;
565 end
= start
+ image
->arch
.elf_headers_sz
- 1;
566 return exclude_mem_range(cmem
, start
, end
);
569 /* Prepare memory map for crash dump kernel */
570 int crash_setup_memmap_entries(struct kimage
*image
, struct boot_params
*params
)
575 struct crash_memmap_data cmd
;
576 struct crash_mem
*cmem
;
578 cmem
= vzalloc(sizeof(struct crash_mem
));
582 memset(&cmd
, 0, sizeof(struct crash_memmap_data
));
585 /* Add first 640K segment */
586 ei
.addr
= image
->arch
.backup_src_start
;
587 ei
.size
= image
->arch
.backup_src_sz
;
589 add_e820_entry(params
, &ei
);
591 /* Add ACPI tables */
592 cmd
.type
= E820_ACPI
;
593 flags
= IORESOURCE_MEM
| IORESOURCE_BUSY
;
594 walk_iomem_res("ACPI Tables", flags
, 0, -1, &cmd
,
595 memmap_entry_callback
);
597 /* Add ACPI Non-volatile Storage */
599 walk_iomem_res("ACPI Non-volatile Storage", flags
, 0, -1, &cmd
,
600 memmap_entry_callback
);
602 /* Add crashk_low_res region */
603 if (crashk_low_res
.end
) {
604 ei
.addr
= crashk_low_res
.start
;
605 ei
.size
= crashk_low_res
.end
- crashk_low_res
.start
+ 1;
607 add_e820_entry(params
, &ei
);
610 /* Exclude some ranges from crashk_res and add rest to memmap */
611 ret
= memmap_exclude_ranges(image
, cmem
, crashk_res
.start
,
616 for (i
= 0; i
< cmem
->nr_ranges
; i
++) {
617 ei
.size
= cmem
->ranges
[i
].end
- cmem
->ranges
[i
].start
+ 1;
619 /* If entry is less than a page, skip it */
620 if (ei
.size
< PAGE_SIZE
)
622 ei
.addr
= cmem
->ranges
[i
].start
;
624 add_e820_entry(params
, &ei
);
632 static int determine_backup_region(u64 start
, u64 end
, void *arg
)
634 struct kimage
*image
= arg
;
636 image
->arch
.backup_src_start
= start
;
637 image
->arch
.backup_src_sz
= end
- start
+ 1;
639 /* Expecting only one range for backup region */
643 int crash_load_segments(struct kimage
*image
)
645 unsigned long src_start
, src_sz
, elf_sz
;
650 * Determine and load a segment for backup area. First 640K RAM
651 * region is backup source
654 ret
= walk_system_ram_res(KEXEC_BACKUP_SRC_START
, KEXEC_BACKUP_SRC_END
,
655 image
, determine_backup_region
);
657 /* Zero or postive return values are ok */
661 src_start
= image
->arch
.backup_src_start
;
662 src_sz
= image
->arch
.backup_src_sz
;
664 /* Add backup segment. */
667 * Ideally there is no source for backup segment. This is
668 * copied in purgatory after crash. Just add a zero filled
669 * segment for now to make sure checksum logic works fine.
671 ret
= kexec_add_buffer(image
, (char *)&crash_zero_bytes
,
672 sizeof(crash_zero_bytes
), src_sz
,
674 &image
->arch
.backup_load_addr
);
677 pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
678 image
->arch
.backup_load_addr
, src_start
, src_sz
);
681 /* Prepare elf headers and add a segment */
682 ret
= prepare_elf_headers(image
, &elf_addr
, &elf_sz
);
686 image
->arch
.elf_headers
= elf_addr
;
687 image
->arch
.elf_headers_sz
= elf_sz
;
689 ret
= kexec_add_buffer(image
, (char *)elf_addr
, elf_sz
, elf_sz
,
690 ELF_CORE_HEADER_ALIGN
, 0, -1, 0,
691 &image
->arch
.elf_load_addr
);
693 vfree((void *)image
->arch
.elf_headers
);
696 pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
697 image
->arch
.elf_load_addr
, elf_sz
, elf_sz
);
701 #endif /* CONFIG_KEXEC_FILE */