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![Vijay Balakrishna](/assets/img/avatar_default.png)
Make kernel GNU build-id available in VMCOREINFO. Having build-id in VMCOREINFO facilitates presenting appropriate kernel namelist image with debug information file to kernel crash dump analysis tools. Currently VMCOREINFO lacks uniquely identifiable key for crash analysis automation. Regarding if this patch is necessary or matching of linux_banner and OSRELEASE in VMCOREINFO employed by crash(8) meets the need -- IMO, build-id approach more foolproof, in most instances it is a cryptographic hash generated using internal code/ELF bits unlike kernel version string upon which linux_banner is based that is external to the code. I feel each is intended for a different purpose. Also OSRELEASE is not suitable when two different kernel builds from same version with different features enabled. Currently for most linux (and non-linux) systems build-id can be extracted using standard methods for file types such as user mode crash dumps, shared libraries, loadable kernel modules etc., This is an exception for linux kernel dump. Having build-id in VMCOREINFO brings some uniformity for automation tools. Tyler said: : I think this is a nice improvement over today's linux_banner approach for : correlating vmlinux to a kernel dump. : : The elf notes parsing in this patch lines up with what is described in in : the "Notes (Nhdr)" section of the elf(5) man page. : : BUILD_ID_MAX is sufficient to hold a sha1 build-id, which is the default : build-id type today in GNU ld(2). It is also sufficient to hold the : "fast" build-id, which is the default build-id type today in LLVM lld(2). Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Link: http://lkml.kernel.org/r/1591849672-34104-1-git-send-email-vijayb@linux.microsoft.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
526 lines
13 KiB
C
526 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* crash.c - kernel crash support code.
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* Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com>
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*/
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#include <linux/crash_core.h>
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#include <linux/utsname.h>
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#include <linux/vmalloc.h>
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#include <asm/page.h>
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#include <asm/sections.h>
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#include <crypto/sha.h>
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/* vmcoreinfo stuff */
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unsigned char *vmcoreinfo_data;
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size_t vmcoreinfo_size;
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u32 *vmcoreinfo_note;
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/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
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static unsigned char *vmcoreinfo_data_safecopy;
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/*
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* parsing the "crashkernel" commandline
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*
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* this code is intended to be called from architecture specific code
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*/
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/*
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* This function parses command lines in the format
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*
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* crashkernel=ramsize-range:size[,...][@offset]
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*
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* The function returns 0 on success and -EINVAL on failure.
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*/
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static int __init parse_crashkernel_mem(char *cmdline,
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unsigned long long system_ram,
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unsigned long long *crash_size,
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unsigned long long *crash_base)
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{
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char *cur = cmdline, *tmp;
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/* for each entry of the comma-separated list */
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do {
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unsigned long long start, end = ULLONG_MAX, size;
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/* get the start of the range */
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start = memparse(cur, &tmp);
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if (cur == tmp) {
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pr_warn("crashkernel: Memory value expected\n");
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return -EINVAL;
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}
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cur = tmp;
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if (*cur != '-') {
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pr_warn("crashkernel: '-' expected\n");
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return -EINVAL;
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}
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cur++;
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/* if no ':' is here, than we read the end */
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if (*cur != ':') {
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end = memparse(cur, &tmp);
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if (cur == tmp) {
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pr_warn("crashkernel: Memory value expected\n");
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return -EINVAL;
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}
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cur = tmp;
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if (end <= start) {
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pr_warn("crashkernel: end <= start\n");
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return -EINVAL;
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}
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}
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if (*cur != ':') {
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pr_warn("crashkernel: ':' expected\n");
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return -EINVAL;
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}
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cur++;
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size = memparse(cur, &tmp);
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if (cur == tmp) {
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pr_warn("Memory value expected\n");
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return -EINVAL;
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}
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cur = tmp;
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if (size >= system_ram) {
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pr_warn("crashkernel: invalid size\n");
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return -EINVAL;
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}
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/* match ? */
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if (system_ram >= start && system_ram < end) {
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*crash_size = size;
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break;
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}
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} while (*cur++ == ',');
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if (*crash_size > 0) {
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while (*cur && *cur != ' ' && *cur != '@')
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cur++;
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if (*cur == '@') {
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cur++;
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*crash_base = memparse(cur, &tmp);
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if (cur == tmp) {
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pr_warn("Memory value expected after '@'\n");
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return -EINVAL;
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}
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}
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} else
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pr_info("crashkernel size resulted in zero bytes\n");
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return 0;
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}
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/*
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* That function parses "simple" (old) crashkernel command lines like
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*
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* crashkernel=size[@offset]
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*
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* It returns 0 on success and -EINVAL on failure.
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*/
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static int __init parse_crashkernel_simple(char *cmdline,
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unsigned long long *crash_size,
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unsigned long long *crash_base)
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{
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char *cur = cmdline;
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*crash_size = memparse(cmdline, &cur);
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if (cmdline == cur) {
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pr_warn("crashkernel: memory value expected\n");
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return -EINVAL;
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}
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if (*cur == '@')
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*crash_base = memparse(cur+1, &cur);
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else if (*cur != ' ' && *cur != '\0') {
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pr_warn("crashkernel: unrecognized char: %c\n", *cur);
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return -EINVAL;
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}
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return 0;
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}
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#define SUFFIX_HIGH 0
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#define SUFFIX_LOW 1
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#define SUFFIX_NULL 2
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static __initdata char *suffix_tbl[] = {
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[SUFFIX_HIGH] = ",high",
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[SUFFIX_LOW] = ",low",
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[SUFFIX_NULL] = NULL,
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};
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/*
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* That function parses "suffix" crashkernel command lines like
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*
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* crashkernel=size,[high|low]
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*
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* It returns 0 on success and -EINVAL on failure.
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*/
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static int __init parse_crashkernel_suffix(char *cmdline,
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unsigned long long *crash_size,
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const char *suffix)
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{
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char *cur = cmdline;
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*crash_size = memparse(cmdline, &cur);
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if (cmdline == cur) {
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pr_warn("crashkernel: memory value expected\n");
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return -EINVAL;
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}
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/* check with suffix */
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if (strncmp(cur, suffix, strlen(suffix))) {
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pr_warn("crashkernel: unrecognized char: %c\n", *cur);
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return -EINVAL;
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}
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cur += strlen(suffix);
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if (*cur != ' ' && *cur != '\0') {
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pr_warn("crashkernel: unrecognized char: %c\n", *cur);
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return -EINVAL;
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}
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return 0;
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}
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static __init char *get_last_crashkernel(char *cmdline,
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const char *name,
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const char *suffix)
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{
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char *p = cmdline, *ck_cmdline = NULL;
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/* find crashkernel and use the last one if there are more */
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p = strstr(p, name);
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while (p) {
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char *end_p = strchr(p, ' ');
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char *q;
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if (!end_p)
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end_p = p + strlen(p);
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if (!suffix) {
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int i;
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/* skip the one with any known suffix */
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for (i = 0; suffix_tbl[i]; i++) {
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q = end_p - strlen(suffix_tbl[i]);
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if (!strncmp(q, suffix_tbl[i],
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strlen(suffix_tbl[i])))
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goto next;
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}
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ck_cmdline = p;
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} else {
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q = end_p - strlen(suffix);
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if (!strncmp(q, suffix, strlen(suffix)))
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ck_cmdline = p;
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}
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next:
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p = strstr(p+1, name);
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}
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if (!ck_cmdline)
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return NULL;
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return ck_cmdline;
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}
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static int __init __parse_crashkernel(char *cmdline,
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unsigned long long system_ram,
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unsigned long long *crash_size,
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unsigned long long *crash_base,
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const char *name,
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const char *suffix)
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{
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char *first_colon, *first_space;
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char *ck_cmdline;
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BUG_ON(!crash_size || !crash_base);
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*crash_size = 0;
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*crash_base = 0;
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ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
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if (!ck_cmdline)
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return -EINVAL;
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ck_cmdline += strlen(name);
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if (suffix)
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return parse_crashkernel_suffix(ck_cmdline, crash_size,
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suffix);
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/*
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* if the commandline contains a ':', then that's the extended
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* syntax -- if not, it must be the classic syntax
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*/
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first_colon = strchr(ck_cmdline, ':');
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first_space = strchr(ck_cmdline, ' ');
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if (first_colon && (!first_space || first_colon < first_space))
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return parse_crashkernel_mem(ck_cmdline, system_ram,
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crash_size, crash_base);
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return parse_crashkernel_simple(ck_cmdline, crash_size, crash_base);
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}
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/*
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* That function is the entry point for command line parsing and should be
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* called from the arch-specific code.
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*/
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int __init parse_crashkernel(char *cmdline,
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unsigned long long system_ram,
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unsigned long long *crash_size,
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unsigned long long *crash_base)
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{
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return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
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"crashkernel=", NULL);
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}
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int __init parse_crashkernel_high(char *cmdline,
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unsigned long long system_ram,
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unsigned long long *crash_size,
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unsigned long long *crash_base)
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{
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return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
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"crashkernel=", suffix_tbl[SUFFIX_HIGH]);
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}
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int __init parse_crashkernel_low(char *cmdline,
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unsigned long long system_ram,
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unsigned long long *crash_size,
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unsigned long long *crash_base)
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{
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return __parse_crashkernel(cmdline, system_ram, crash_size, crash_base,
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"crashkernel=", suffix_tbl[SUFFIX_LOW]);
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}
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Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
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void *data, size_t data_len)
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{
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struct elf_note *note = (struct elf_note *)buf;
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note->n_namesz = strlen(name) + 1;
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note->n_descsz = data_len;
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note->n_type = type;
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buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
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memcpy(buf, name, note->n_namesz);
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buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
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memcpy(buf, data, data_len);
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buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
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return buf;
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}
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void final_note(Elf_Word *buf)
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{
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memset(buf, 0, sizeof(struct elf_note));
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}
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static void update_vmcoreinfo_note(void)
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{
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u32 *buf = vmcoreinfo_note;
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if (!vmcoreinfo_size)
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return;
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buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data,
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vmcoreinfo_size);
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final_note(buf);
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}
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void crash_update_vmcoreinfo_safecopy(void *ptr)
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{
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if (ptr)
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memcpy(ptr, vmcoreinfo_data, vmcoreinfo_size);
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vmcoreinfo_data_safecopy = ptr;
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}
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void crash_save_vmcoreinfo(void)
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{
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if (!vmcoreinfo_note)
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return;
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/* Use the safe copy to generate vmcoreinfo note if have */
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if (vmcoreinfo_data_safecopy)
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vmcoreinfo_data = vmcoreinfo_data_safecopy;
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vmcoreinfo_append_str("CRASHTIME=%lld\n", ktime_get_real_seconds());
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update_vmcoreinfo_note();
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}
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void vmcoreinfo_append_str(const char *fmt, ...)
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{
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va_list args;
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char buf[0x50];
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size_t r;
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va_start(args, fmt);
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r = vscnprintf(buf, sizeof(buf), fmt, args);
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va_end(args);
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r = min(r, (size_t)VMCOREINFO_BYTES - vmcoreinfo_size);
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memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);
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vmcoreinfo_size += r;
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}
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/*
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* provide an empty default implementation here -- architecture
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* code may override this
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*/
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void __weak arch_crash_save_vmcoreinfo(void)
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{}
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phys_addr_t __weak paddr_vmcoreinfo_note(void)
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{
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return __pa(vmcoreinfo_note);
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}
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EXPORT_SYMBOL(paddr_vmcoreinfo_note);
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#define NOTES_SIZE (&__stop_notes - &__start_notes)
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#define BUILD_ID_MAX SHA1_DIGEST_SIZE
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#define NT_GNU_BUILD_ID 3
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struct elf_note_section {
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struct elf_note n_hdr;
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u8 n_data[];
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};
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/*
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* Add build ID from .notes section as generated by the GNU ld(1)
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* or LLVM lld(1) --build-id option.
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*/
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static void add_build_id_vmcoreinfo(void)
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{
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char build_id[BUILD_ID_MAX * 2 + 1];
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int n_remain = NOTES_SIZE;
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while (n_remain >= sizeof(struct elf_note)) {
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const struct elf_note_section *note_sec =
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&__start_notes + NOTES_SIZE - n_remain;
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const u32 n_namesz = note_sec->n_hdr.n_namesz;
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if (note_sec->n_hdr.n_type == NT_GNU_BUILD_ID &&
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n_namesz != 0 &&
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!strcmp((char *)¬e_sec->n_data[0], "GNU")) {
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if (note_sec->n_hdr.n_descsz <= BUILD_ID_MAX) {
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const u32 n_descsz = note_sec->n_hdr.n_descsz;
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const u8 *s = ¬e_sec->n_data[n_namesz];
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s = PTR_ALIGN(s, 4);
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bin2hex(build_id, s, n_descsz);
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build_id[2 * n_descsz] = '\0';
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VMCOREINFO_BUILD_ID(build_id);
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return;
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}
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pr_warn("Build ID is too large to include in vmcoreinfo: %u > %u\n",
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note_sec->n_hdr.n_descsz,
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BUILD_ID_MAX);
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return;
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}
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n_remain -= sizeof(struct elf_note) +
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ALIGN(note_sec->n_hdr.n_namesz, 4) +
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ALIGN(note_sec->n_hdr.n_descsz, 4);
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}
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}
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static int __init crash_save_vmcoreinfo_init(void)
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{
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vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL);
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if (!vmcoreinfo_data) {
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pr_warn("Memory allocation for vmcoreinfo_data failed\n");
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return -ENOMEM;
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}
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vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE,
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GFP_KERNEL | __GFP_ZERO);
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if (!vmcoreinfo_note) {
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free_page((unsigned long)vmcoreinfo_data);
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vmcoreinfo_data = NULL;
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pr_warn("Memory allocation for vmcoreinfo_note failed\n");
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return -ENOMEM;
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}
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VMCOREINFO_OSRELEASE(init_uts_ns.name.release);
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add_build_id_vmcoreinfo();
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VMCOREINFO_PAGESIZE(PAGE_SIZE);
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VMCOREINFO_SYMBOL(init_uts_ns);
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VMCOREINFO_SYMBOL(node_online_map);
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#ifdef CONFIG_MMU
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VMCOREINFO_SYMBOL_ARRAY(swapper_pg_dir);
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#endif
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VMCOREINFO_SYMBOL(_stext);
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VMCOREINFO_SYMBOL(vmap_area_list);
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#ifndef CONFIG_NEED_MULTIPLE_NODES
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VMCOREINFO_SYMBOL(mem_map);
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VMCOREINFO_SYMBOL(contig_page_data);
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#endif
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#ifdef CONFIG_SPARSEMEM
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VMCOREINFO_SYMBOL_ARRAY(mem_section);
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VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
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VMCOREINFO_STRUCT_SIZE(mem_section);
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VMCOREINFO_OFFSET(mem_section, section_mem_map);
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VMCOREINFO_NUMBER(MAX_PHYSMEM_BITS);
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#endif
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VMCOREINFO_STRUCT_SIZE(page);
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VMCOREINFO_STRUCT_SIZE(pglist_data);
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VMCOREINFO_STRUCT_SIZE(zone);
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VMCOREINFO_STRUCT_SIZE(free_area);
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VMCOREINFO_STRUCT_SIZE(list_head);
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VMCOREINFO_SIZE(nodemask_t);
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VMCOREINFO_OFFSET(page, flags);
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VMCOREINFO_OFFSET(page, _refcount);
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VMCOREINFO_OFFSET(page, mapping);
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VMCOREINFO_OFFSET(page, lru);
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VMCOREINFO_OFFSET(page, _mapcount);
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VMCOREINFO_OFFSET(page, private);
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VMCOREINFO_OFFSET(page, compound_dtor);
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VMCOREINFO_OFFSET(page, compound_order);
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VMCOREINFO_OFFSET(page, compound_head);
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VMCOREINFO_OFFSET(pglist_data, node_zones);
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VMCOREINFO_OFFSET(pglist_data, nr_zones);
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#ifdef CONFIG_FLAT_NODE_MEM_MAP
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VMCOREINFO_OFFSET(pglist_data, node_mem_map);
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#endif
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VMCOREINFO_OFFSET(pglist_data, node_start_pfn);
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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_swapbacked);
|
|
VMCOREINFO_NUMBER(PG_slab);
|
|
#ifdef CONFIG_MEMORY_FAILURE
|
|
VMCOREINFO_NUMBER(PG_hwpoison);
|
|
#endif
|
|
VMCOREINFO_NUMBER(PG_head_mask);
|
|
#define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy)
|
|
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
|
|
#ifdef CONFIG_HUGETLB_PAGE
|
|
VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);
|
|
#define PAGE_OFFLINE_MAPCOUNT_VALUE (~PG_offline)
|
|
VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
|
|
#endif
|
|
|
|
arch_crash_save_vmcoreinfo();
|
|
update_vmcoreinfo_note();
|
|
|
|
return 0;
|
|
}
|
|
|
|
subsys_initcall(crash_save_vmcoreinfo_init);
|