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![Baoquan He](/assets/img/avatar_default.png)
There are regression reports[1][2] that crashkernel region on x86_64 can't be added into iomem tree sometime. This causes the later failure of kdump loading. This happened after commit4a693ce65b
("kdump: defer the insertion of crashkernel resources") was merged. Even though, these reported issues are proved to be related to other component, they are just exposed after above commmit applied, I still would like to keep crashk_res and crashk_low_res being added into iomem early as before because the early adding has been always there on x86_64 and working very well. For safety of kdump, Let's change it back. Here, add a macro HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY to limit that only ARCH defining the macro can have the early adding crashk_res/_low_res into iomem. Then define HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY on x86 to enable it. Note: In reserve_crashkernel_low(), there's a remnant of crashk_low_res handling which was mistakenly added back in commit85fcde402d
("kexec: split crashkernel reservation code out from crash_core.c"). [1] [PATCH V2] x86/kexec: do not update E820 kexec table for setup_data https://lore.kernel.org/all/Zfv8iCL6CT2JqLIC@darkstar.users.ipa.redhat.com/T/#u [2] Question about Address Range Validation in Crash Kernel Allocation https://lore.kernel.org/all/4eeac1f733584855965a2ea62fa4da58@huawei.com/T/#u Link: https://lkml.kernel.org/r/ZgDYemRQ2jxjLkq+@MiWiFi-R3L-srv Fixes:4a693ce65b
("kdump: defer the insertion of crashkernel resources") Signed-off-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Huacai Chen <chenhuacai@loongson.cn> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Li Huafei <lihuafei1@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
472 lines
11 KiB
C
472 lines
11 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/buildid.h>
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#include <linux/init.h>
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#include <linux/utsname.h>
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#include <linux/vmalloc.h>
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#include <linux/sizes.h>
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#include <linux/kexec.h>
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#include <linux/memory.h>
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#include <linux/cpuhotplug.h>
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#include <linux/memblock.h>
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#include <linux/kexec.h>
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#include <linux/kmemleak.h>
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#include <asm/page.h>
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#include <asm/sections.h>
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#include <crypto/sha1.h>
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#include "kallsyms_internal.h"
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#include "kexec_internal.h"
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/* Location of the reserved area for the crash kernel */
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struct resource crashk_res = {
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.name = "Crash kernel",
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.start = 0,
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.end = 0,
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.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
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.desc = IORES_DESC_CRASH_KERNEL
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};
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struct resource crashk_low_res = {
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.name = "Crash kernel",
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.start = 0,
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.end = 0,
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.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
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.desc = IORES_DESC_CRASH_KERNEL
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};
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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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unsigned long long total_mem = system_ram;
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/*
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* Firmware sometimes reserves some memory regions for its own use,
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* so the system memory size is less than the actual physical memory
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* size. Work around this by rounding up the total size to 128M,
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* which is enough for most test cases.
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*/
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total_mem = roundup(total_mem, SZ_128M);
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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 >= total_mem) {
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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 (total_mem >= start && total_mem < 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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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 *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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char *name = "crashkernel=";
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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 -ENOENT;
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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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* If crashkernel=,high|low is supported on architecture, non-NULL values
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* should be passed to parameters 'low_size' and 'high'.
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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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unsigned long long *low_size,
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bool *high)
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{
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int ret;
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/* crashkernel=X[@offset] */
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ret = __parse_crashkernel(cmdline, system_ram, crash_size,
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crash_base, NULL);
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#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
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/*
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* If non-NULL 'high' passed in and no normal crashkernel
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* setting detected, try parsing crashkernel=,high|low.
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*/
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if (high && ret == -ENOENT) {
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ret = __parse_crashkernel(cmdline, 0, crash_size,
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crash_base, suffix_tbl[SUFFIX_HIGH]);
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if (ret || !*crash_size)
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return -EINVAL;
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/*
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* crashkernel=Y,low can be specified or not, but invalid value
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* is not allowed.
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*/
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ret = __parse_crashkernel(cmdline, 0, low_size,
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crash_base, suffix_tbl[SUFFIX_LOW]);
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if (ret == -ENOENT) {
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*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
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ret = 0;
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} else if (ret) {
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return ret;
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}
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*high = true;
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}
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#endif
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if (!*crash_size)
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ret = -EINVAL;
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return ret;
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}
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/*
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* Add a dummy early_param handler to mark crashkernel= as a known command line
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* parameter and suppress incorrect warnings in init/main.c.
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*/
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static int __init parse_crashkernel_dummy(char *arg)
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{
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return 0;
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}
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early_param("crashkernel", parse_crashkernel_dummy);
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#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
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static int __init reserve_crashkernel_low(unsigned long long low_size)
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{
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#ifdef CONFIG_64BIT
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unsigned long long low_base;
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low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
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if (!low_base) {
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pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
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return -ENOMEM;
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}
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pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
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low_base, low_base + low_size, low_size >> 20);
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crashk_low_res.start = low_base;
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crashk_low_res.end = low_base + low_size - 1;
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#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
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insert_resource(&iomem_resource, &crashk_low_res);
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#endif
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#endif
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return 0;
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}
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void __init reserve_crashkernel_generic(char *cmdline,
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unsigned long long crash_size,
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unsigned long long crash_base,
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unsigned long long crash_low_size,
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bool high)
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{
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unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
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bool fixed_base = false;
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/* User specifies base address explicitly. */
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if (crash_base) {
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fixed_base = true;
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search_base = crash_base;
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search_end = crash_base + crash_size;
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} else if (high) {
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search_base = CRASH_ADDR_LOW_MAX;
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search_end = CRASH_ADDR_HIGH_MAX;
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}
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retry:
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crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
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search_base, search_end);
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if (!crash_base) {
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/*
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* For crashkernel=size[KMG]@offset[KMG], print out failure
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* message if can't reserve the specified region.
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*/
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if (fixed_base) {
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pr_warn("crashkernel reservation failed - memory is in use.\n");
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return;
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}
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/*
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* For crashkernel=size[KMG], if the first attempt was for
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* low memory, fall back to high memory, the minimum required
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* low memory will be reserved later.
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*/
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if (!high && search_end == CRASH_ADDR_LOW_MAX) {
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search_end = CRASH_ADDR_HIGH_MAX;
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search_base = CRASH_ADDR_LOW_MAX;
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crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
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goto retry;
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}
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/*
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* For crashkernel=size[KMG],high, if the first attempt was
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* for high memory, fall back to low memory.
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*/
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if (high && search_end == CRASH_ADDR_HIGH_MAX) {
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search_end = CRASH_ADDR_LOW_MAX;
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search_base = 0;
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goto retry;
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}
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pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
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crash_size);
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return;
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}
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if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
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crash_low_size && reserve_crashkernel_low(crash_low_size)) {
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memblock_phys_free(crash_base, crash_size);
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return;
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}
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pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
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crash_base, crash_base + crash_size, crash_size >> 20);
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/*
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* The crashkernel memory will be removed from the kernel linear
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* map. Inform kmemleak so that it won't try to access it.
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*/
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kmemleak_ignore_phys(crash_base);
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if (crashk_low_res.end)
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kmemleak_ignore_phys(crashk_low_res.start);
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crashk_res.start = crash_base;
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crashk_res.end = crash_base + crash_size - 1;
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#ifdef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
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insert_resource(&iomem_resource, &crashk_res);
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#endif
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}
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#ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
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static __init int insert_crashkernel_resources(void)
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{
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if (crashk_res.start < crashk_res.end)
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insert_resource(&iomem_resource, &crashk_res);
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if (crashk_low_res.start < crashk_low_res.end)
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insert_resource(&iomem_resource, &crashk_low_res);
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return 0;
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}
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early_initcall(insert_crashkernel_resources);
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#endif
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#endif
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