Quelle  vmcore_info.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * crash.c - kernel crash support code.
 * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
 */

#include <linux/buildid.h>
#include <linux/init.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
#include <linux/kexec.h>
#include <linux/memory.h>
#include <linux/cpuhotplug.h>
#include <linux/memblock.h>
#include <linux/kmemleak.h>

#include <asm/page.h>
#include <asm/sections.h>

#include <crypto/sha1.h>

#include "kallsyms_internal.h"
#include "kexec_internal.h"

/* vmcoreinfo stuff */
unsigned char *vmcoreinfo_data;
size_t vmcoreinfo_size;
u32 *vmcoreinfo_note;

/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
static unsigned char *vmcoreinfo_data_safecopy;

Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
     void *data, size_t data_len)
{
 struct elf_note *note = (struct elf_note *)buf;

 note->n_namesz = strlen(name) + 1;
 note->n_descsz = data_len;
 note->n_type   = type;
 buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
 memcpy(buf, name, note->n_namesz);
 buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
 memcpy(buf, data, data_len);
 buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));

 return buf;
}

void final_note(Elf_Word *buf)
{
 memset(buf, 0, sizeof(struct elf_note));
}

static void update_vmcoreinfo_note(void)
{
 u32 *buf = vmcoreinfo_note;

 if (!vmcoreinfo_size)
  return;
 buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
         vmcoreinfo_size);
 final_note(buf);
}

void crash_update_vmcoreinfo_safecopy(void *ptr)
{
 if (ptr)
  memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);

 vmcoreinfo_data_safecopy = ptr;
}

void crash_save_vmcoreinfo(void)
{
 if (!vmcoreinfo_note)
  return;

 /* Use the safe copy to generate vmcoreinfo note if have */
 if (vmcoreinfo_data_safecopy)
  vmcoreinfo_data = vmcoreinfo_data_safecopy;

 vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
 update_vmcoreinfo_note();
}

void vmcoreinfo_append_str(const char *fmt, ...)
{
 va_list args;
 char buf[0x50];
 size_t r;

 va_start(args, fmt);
 r = vscnprintf(buf, sizeof(buf), fmt, args);
 va_end(args);

 r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);

 memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);

 vmcoreinfo_size += r;

 WARN_ONCE(vmcoreinfo_size == VMCOREINFO_BYTES,
    "vmcoreinfo data exceeds allocated size, truncating");
}

/*
 * provide an empty default implementation here -- architecture
 * code may override this
 */
void __weak arch_crash_save_vmcoreinfo(void)
{}

phys_addr_t __weak paddr_vmcoreinfo_note(void)
{
 return __pa(vmcoreinfo_note);
}
EXPORT_SYMBOL(paddr_vmcoreinfo_note);

static int __init crash_save_vmcoreinfo_init(void)
{
 vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
 if (!vmcoreinfo_data) {
  pr_warn("Memory allocation for vmcoreinfo_data failed\n");
  return -ENOMEM;
 }

 vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
      GFP_KERNEL | __GFP_ZERO);
 if (!vmcoreinfo_note) {
  free_page((unsigned long)vmcoreinfo_data);
  vmcoreinfo_data = NULL;
  pr_warn("Memory allocation for vmcoreinfo_note failed\n");
  return -ENOMEM;
 }

 VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
 VMCOREINFO_BUILD_ID();
 VMCOREINFO_PAGESIZE(PAGE_SIZE);

 VMCOREINFO_SYMBOL(init_uts_ns);
 VMCOREINFO_OFFSET(uts_namespace, name);
 VMCOREINFO_SYMBOL(node_online_map);
#ifdef CONFIG_MMU
 VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
#endif
 VMCOREINFO_SYMBOL(_stext);
 vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", (unsigned long) VMALLOC_START);

#ifndef CONFIG_NUMA
 VMCOREINFO_SYMBOL(mem_map);
 VMCOREINFO_SYMBOL(contig_page_data);
#endif
#ifdef CONFIG_SPARSEMEM_VMEMMAP
 VMCOREINFO_SYMBOL_ARRAY(vmemmap);
#endif
#ifdef CONFIG_SPARSEMEM
 VMCOREINFO_SYMBOL_ARRAY(mem_section);
 VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
 VMCOREINFO_STRUCT_SIZE(mem_section);
 VMCOREINFO_OFFSET(mem_section, section_mem_map);
 VMCOREINFO_NUMBER(SECTION_SIZE_BITS);
 VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
#endif
 VMCOREINFO_STRUCT_SIZE(page);
 VMCOREINFO_STRUCT_SIZE(pglist_data);
 VMCOREINFO_STRUCT_SIZE(zone);
 VMCOREINFO_STRUCT_SIZE(free_area);
 VMCOREINFO_STRUCT_SIZE(list_head);
 VMCOREINFO_SIZE(nodemask_t);
 VMCOREINFO_OFFSET(page, flags);
 VMCOREINFO_OFFSET(page, _refcount);
 VMCOREINFO_OFFSET(page, mapping);
 VMCOREINFO_OFFSET(page, lru);
 VMCOREINFO_OFFSET(page, _mapcount);
 VMCOREINFO_OFFSET(page, private);
 VMCOREINFO_OFFSET(page, compound_head);
 VMCOREINFO_OFFSET(pglist_data, node_zones);
 VMCOREINFO_OFFSET(pglist_data, nr_zones);
#ifdef CONFIG_FLATMEM
 VMCOREINFO_OFFSET(pglist_data, node_mem_map);
#endif
 VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
 VMCOREINFO_OFFSET(pglist_data, node_spanned_pages);
 VMCOREINFO_OFFSET(pglist_data, node_id);
 VMCOREINFO_OFFSET(zone, free_area);
 VMCOREINFO_OFFSET(zone, vm_stat);
 VMCOREINFO_OFFSET(zone, spanned_pages);
 VMCOREINFO_OFFSET(free_area, free_list);
 VMCOREINFO_OFFSET(list_head, next);
 VMCOREINFO_OFFSET(list_head, prev);
 VMCOREINFO_LENGTH(zone.free_area, NR_PAGE_ORDERS);
 log_buf_vmcoreinfo_setup();
 VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
 VMCOREINFO_NUMBER(NR_FREE_PAGES);
 VMCOREINFO_NUMBER(PG_lru);
 VMCOREINFO_NUMBER(PG_private);
 VMCOREINFO_NUMBER(PG_swapcache);
 VMCOREINFO_NUMBER(PG_swapbacked);
#define PAGE_SLAB_MAPCOUNT_VALUE (PGTY_slab << 24)
 VMCOREINFO_NUMBER(PAGE_SLAB_MAPCOUNT_VALUE);
#ifdef CONFIG_MEMORY_FAILURE
 VMCOREINFO_NUMBER(PG_hwpoison);
#endif
 VMCOREINFO_NUMBER(PG_head_mask);
#define PAGE_BUDDY_MAPCOUNT_VALUE (PGTY_buddy << 24)
 VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
#define PAGE_HUGETLB_MAPCOUNT_VALUE (PGTY_hugetlb << 24)
 VMCOREINFO_NUMBER(PAGE_HUGETLB_MAPCOUNT_VALUE);
#define PAGE_OFFLINE_MAPCOUNT_VALUE (PGTY_offline << 24)
 VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
#ifdef CONFIG_UNACCEPTED_MEMORY
#define PAGE_UNACCEPTED_MAPCOUNT_VALUE (PGTY_unaccepted << 24)
 VMCOREINFO_NUMBER(PAGE_UNACCEPTED_MAPCOUNT_VALUE);
#endif

#ifdef CONFIG_KALLSYMS
 VMCOREINFO_SYMBOL(kallsyms_names);
 VMCOREINFO_SYMBOL(kallsyms_num_syms);
 VMCOREINFO_SYMBOL(kallsyms_token_table);
 VMCOREINFO_SYMBOL(kallsyms_token_index);
 VMCOREINFO_SYMBOL(kallsyms_offsets);
 VMCOREINFO_SYMBOL(kallsyms_relative_base);
#endif /* CONFIG_KALLSYMS */

 arch_crash_save_vmcoreinfo();
 update_vmcoreinfo_note();

 return 0;
}

subsys_initcall(crash_save_vmcoreinfo_init);