cregit-Linux how code gets into the kernel

Release 4.13 kernel/crash_core.c

Directory: kernel
/*
 * crash.c - kernel crash support code.
 * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */

#include <linux/crash_core.h>
#include <linux/utsname.h>
#include <linux/vmalloc.h>

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

/* vmcoreinfo stuff */

static unsigned char *vmcoreinfo_data;

static 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;

/*
 * parsing the "crashkernel" commandline
 *
 * this code is intended to be called from architecture specific code
 */


/*
 * This function parses command lines in the format
 *
 *   crashkernel=ramsize-range:size[,...][@offset]
 *
 * The function returns 0 on success and -EINVAL on failure.
 */

static int __init parse_crashkernel_mem(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base) { char *cur = cmdline, *tmp; /* for each entry of the comma-separated list */ do { unsigned long long start, end = ULLONG_MAX, size; /* get the start of the range */ start = memparse(cur, &tmp); if (cur == tmp) { pr_warn("crashkernel: Memory value expected\n"); return -EINVAL; } cur = tmp; if (*cur != '-') { pr_warn("crashkernel: '-' expected\n"); return -EINVAL; } cur++; /* if no ':' is here, than we read the end */ if (*cur != ':') { end = memparse(cur, &tmp); if (cur == tmp) { pr_warn("crashkernel: Memory value expected\n"); return -EINVAL; } cur = tmp; if (end <= start) { pr_warn("crashkernel: end <= start\n"); return -EINVAL; } } if (*cur != ':') { pr_warn("crashkernel: ':' expected\n"); return -EINVAL; } cur++; size = memparse(cur, &tmp); if (cur == tmp) { pr_warn("Memory value expected\n"); return -EINVAL; } cur = tmp; if (size >= system_ram) { pr_warn("crashkernel: invalid size\n"); return -EINVAL; } /* match ? */ if (system_ram >= start && system_ram < end) { *crash_size = size; break; } } while (*cur++ == ','); if (*crash_size > 0) { while (*cur && *cur != ' ' && *cur != '@') cur++; if (*cur == '@') { cur++; *crash_base = memparse(cur, &tmp); if (cur == tmp) { pr_warn("Memory value expected after '@'\n"); return -EINVAL; } } } return 0; }

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/* * That function parses "simple" (old) crashkernel command lines like * * crashkernel=size[@offset] * * It returns 0 on success and -EINVAL on failure. */
static int __init parse_crashkernel_simple(char *cmdline, unsigned long long *crash_size, unsigned long long *crash_base) { char *cur = cmdline; *crash_size = memparse(cmdline, &cur); if (cmdline == cur) { pr_warn("crashkernel: memory value expected\n"); return -EINVAL; } if (*cur == '@') *crash_base = memparse(cur+1, &cur); else if (*cur != ' ' && *cur != '\0') { pr_warn("crashkernel: unrecognized char: %c\n", *cur); return -EINVAL; } return 0; }

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#define SUFFIX_HIGH 0 #define SUFFIX_LOW 1 #define SUFFIX_NULL 2 static __initdata char *suffix_tbl[] = { [SUFFIX_HIGH] = ",high", [SUFFIX_LOW] = ",low", [SUFFIX_NULL] = NULL, }; /* * That function parses "suffix" crashkernel command lines like * * crashkernel=size,[high|low] * * It returns 0 on success and -EINVAL on failure. */
static int __init parse_crashkernel_suffix(char *cmdline, unsigned long long *crash_size, const char *suffix) { char *cur = cmdline; *crash_size = memparse(cmdline, &cur); if (cmdline == cur) { pr_warn("crashkernel: memory value expected\n"); return -EINVAL; } /* check with suffix */ if (strncmp(cur, suffix, strlen(suffix))) { pr_warn("crashkernel: unrecognized char: %c\n", *cur); return -EINVAL; } cur += strlen(suffix); if (*cur != ' ' && *cur != '\0') { pr_warn("crashkernel: unrecognized char: %c\n", *cur); return -EINVAL; } return 0; }

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static __init char *get_last_crashkernel(char *cmdline, const char *name, const char *suffix) { char *p = cmdline, *ck_cmdline = NULL; /* find crashkernel and use the last one if there are more */ p = strstr(p, name); while (p) { char *end_p = strchr(p, ' '); char *q; if (!end_p) end_p = p + strlen(p); if (!suffix) { int i; /* skip the one with any known suffix */ for (i = 0; suffix_tbl[i]; i++) { q = end_p - strlen(suffix_tbl[i]); if (!strncmp(q, suffix_tbl[i], strlen(suffix_tbl[i]))) goto next; } ck_cmdline = p; } else { q = end_p - strlen(suffix); if (!strncmp(q, suffix, strlen(suffix))) ck_cmdline = p; } next: p = strstr(p+1, name); } if (!ck_cmdline) return NULL; return ck_cmdline; }

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static int __init __parse_crashkernel(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base, const char *name, const char *suffix) { char *first_colon, *first_space; char *ck_cmdline; BUG_ON(!crash_size || !crash_base); *crash_size = 0; *crash_base = 0; ck_cmdline = get_last_crashkernel(cmdline, name, suffix); if (!ck_cmdline) return -EINVAL; ck_cmdline += strlen(name); if (suffix) return parse_crashkernel_suffix(ck_cmdline, crash_size, suffix); /* * if the commandline contains a ':', then that's the extended * syntax -- if not, it must be the classic syntax */ first_colon = strchr(ck_cmdline, ':'); first_space = strchr(ck_cmdline, ' '); if (first_colon && (!first_space || first_colon < first_space)) return parse_crashkernel_mem(ck_cmdline, system_ram, crash_size, crash_base); return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base); }

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/* * That function is the entry point for command line parsing and should be * called from the arch-specific code. */
int __init parse_crashkernel(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base) { return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, "crashkernel=", NULL); }

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int __init parse_crashkernel_high(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base) { return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, "crashkernel=", suffix_tbl[SUFFIX_HIGH]); }

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int __init parse_crashkernel_low(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base) { return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base, "crashkernel=", suffix_tbl[SUFFIX_LOW]); }

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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; }

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

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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); }

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

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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=%ld\n", get_seconds()); update_vmcoreinfo_note(); }

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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; }

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

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

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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_PAGESIZE(PAGE_SIZE); VMCOREINFO_SYMBOL(init_uts_ns); VMCOREINFO_SYMBOL(node_online_map); #ifdef CONFIG_MMU VMCOREINFO_SYMBOL(swapper_pg_dir); #endif VMCOREINFO_SYMBOL(_stext); VMCOREINFO_SYMBOL(vmap_area_list); #ifndef CONFIG_NEED_MULTIPLE_NODES VMCOREINFO_SYMBOL(mem_map); VMCOREINFO_SYMBOL(contig_page_data); #endif #ifdef CONFIG_SPARSEMEM VMCOREINFO_SYMBOL(mem_section); VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS); VMCOREINFO_STRUCT_SIZE(mem_section); VMCOREINFO_OFFSET(mem_section, section_mem_map); #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_dtor); VMCOREINFO_OFFSET(page, compound_order); VMCOREINFO_OFFSET(page, compound_head); VMCOREINFO_OFFSET(pglist_data, node_zones); VMCOREINFO_OFFSET(pglist_data, nr_zones); #ifdef CONFIG_FLAT_NODE_MEM_MAP 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_OFFSET(vmap_area, va_start); VMCOREINFO_OFFSET(vmap_area, list); VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER); 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_slab); #ifdef CONFIG_MEMORY_FAILURE VMCOREINFO_NUMBER(PG_hwpoison); #endif VMCOREINFO_NUMBER(PG_head_mask); VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE); #ifdef CONFIG_HUGETLB_PAGE VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR); #endif arch_crash_save_vmcoreinfo(); update_vmcoreinfo_note(); return 0; }

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subsys_initcall(crash_save_vmcoreinfo_init);

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Directory: kernel
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