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kexec: split crashkernel reservation code out from crash_core.c

Browse source 
Patch series "Split crash out from kexec and clean up related config
items", v3.

Motivation:
=============
Previously, LKP reported a building error. When investigating, it can't
be resolved reasonablly with the present messy kdump config items.

 https://lore.kernel.org/oe-kbuild-all/202312182200.Ka7MzifQ-lkp@intel.com/

The kdump (crash dumping) related config items could causes confusions:

Firstly,

CRASH_CORE enables codes including
 - crashkernel reservation;
 - elfcorehdr updating;
 - vmcoreinfo exporting;
 - crash hotplug handling;

Now fadump of powerpc, kcore dynamic debugging and kdump all selects
CRASH_CORE, while fadump
 - fadump needs crashkernel parsing, vmcoreinfo exporting, and accessing
   global variable 'elfcorehdr_addr';
 - kcore only needs vmcoreinfo exporting;
 - kdump needs all of the current kernel/crash_core.c.

So only enabling PROC_CORE or FA_DUMP will enable CRASH_CORE, this
mislead people that we enable crash dumping, actual it's not.

Secondly,

It's not reasonable to allow KEXEC_CORE select CRASH_CORE.

Because KEXEC_CORE enables codes which allocate control pages, copy
kexec/kdump segments, and prepare for switching. These codes are
shared by both kexec reboot and kdump. We could want kexec reboot,
but disable kdump. In that case, CRASH_CORE should not be selected.

 --------------------
 CONFIG_CRASH_CORE=y
 CONFIG_KEXEC_CORE=y
 CONFIG_KEXEC=y
 CONFIG_KEXEC_FILE=y
 ---------------------

Thirdly,

It's not reasonable to allow CRASH_DUMP select KEXEC_CORE.

That could make KEXEC_CORE, CRASH_DUMP are enabled independently from
KEXEC or KEXEC_FILE. However, w/o KEXEC or KEXEC_FILE, the KEXEC_CORE
code built in doesn't make any sense because no kernel loading or
switching will happen to utilize the KEXEC_CORE code.
 ---------------------
 CONFIG_CRASH_CORE=y
 CONFIG_KEXEC_CORE=y
 CONFIG_CRASH_DUMP=y
 ---------------------

In this case, what is worse, on arch sh and arm, KEXEC relies on MMU,
while CRASH_DUMP can still be enabled when !MMU, then compiling error is
seen as the lkp test robot reported in above link.

 ------arch/sh/Kconfig------
 config ARCH_SUPPORTS_KEXEC
         def_bool MMU

 config ARCH_SUPPORTS_CRASH_DUMP
         def_bool BROKEN_ON_SMP
 ---------------------------

Changes:
===========
1, split out crash_reserve.c from crash_core.c;
2, split out vmcore_infoc. from crash_core.c;
3, move crash related codes in kexec_core.c into crash_core.c;
4, remove dependency of FA_DUMP on CRASH_DUMP;
5, clean up kdump related config items;
6, wrap up crash codes in crash related ifdefs on all 8 arch-es
   which support crash dumping, except of ppc;

Achievement:
===========
With above changes, I can rearrange the config item logic as below (the right
item depends on or is selected by the left item):

    PROC_KCORE -----------> VMCORE_INFO

               |----------> VMCORE_INFO
    FA_DUMP----|
               |----------> CRASH_RESERVE

                                                    ---->VMCORE_INFO
                                                   /
                                                   |---->CRASH_RESERVE
    KEXEC      --|                                /|
                 |--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE
    KEXEC_FILE --|                               \ |
                                                   \---->CRASH_HOTPLUG


    KEXEC      --|
                 |--> KEXEC_CORE (for kexec reboot only)
    KEXEC_FILE --|

Test
========
On all 8 architectures, including x86_64, arm64, s390x, sh, arm, mips,
riscv, loongarch, I did below three cases of config item setting and
building all passed. Take configs on x86_64 as exampmle here:

(1) Both CONFIG_KEXEC and KEXEC_FILE is unset, then all kexec/kdump
items are unset automatically:
# Kexec and crash features
# CONFIG_KEXEC is not set
# CONFIG_KEXEC_FILE is not set
# end of Kexec and crash features

(2) set CONFIG_KEXEC_FILE and 'make olddefconfig':
---------------
# Kexec and crash features
CONFIG_CRASH_RESERVE=y
CONFIG_VMCORE_INFO=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC_FILE=y
CONFIG_CRASH_DUMP=y
CONFIG_CRASH_HOTPLUG=y
CONFIG_CRASH_MAX_MEMORY_RANGES=8192
# end of Kexec and crash features
---------------

(3) unset CONFIG_CRASH_DUMP in case 2 and execute 'make olddefconfig':
------------------------
# Kexec and crash features
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC_FILE=y
# end of Kexec and crash features
------------------------

Note:
For ppc, it needs investigation to make clear how to split out crash
code in arch folder. Hope Hari and Pingfan can help have a look, see if
it's doable. Now, I make it either have both kexec and crash enabled, or
disable both of them altogether.


This patch (of 14):

Both kdump and fa_dump of ppc rely on crashkernel reservation.  Move the
relevant codes into separate files: crash_reserve.c,
include/linux/crash_reserve.h.

And also add config item CRASH_RESERVE to control its enabling of the
codes.  And update config items which has relationship with crashkernel
reservation.

And also change ifdeffery from CONFIG_CRASH_CORE to CONFIG_CRASH_RESERVE
when those scopes are only crashkernel reservation related.

And also rename arch/XXX/include/asm/{crash_core.h => crash_reserve.h} on
arm64, x86 and risc-v because those architectures' crash_core.h is only
related to crashkernel reservation.

[akpm@linux-foundation.org: s/CRASH_RESEERVE/CRASH_RESERVE/, per Klara Modin]
Link: https://lkml.kernel.org/r/20240124051254.67105-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20240124051254.67105-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Baoquan He 2024-01-24 13:12:41 +08:00 committed by Andrew Morton
parent 8be4d46e12
commit 85fcde402d
15 changed files with 531 additions and 491 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
arch/arm64/Kconfig
View file

@ -1519,7 +1519,7 @@ config ARCH_SUPPORTS_CRASH_DUMP
def_bool y
config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
def_bool CRASH_CORE
def_bool CRASH_RESERVE
config TRANS_TABLE
def_bool y

4
arch/arm64/include/asm/crash_core.h → arch/arm64/include/asm/crash_reserve.h
View file

@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _ARM64_CRASH_CORE_H
#define _ARM64_CRASH_CORE_H
#ifndef _ARM64_CRASH_RESERVE_H
#define _ARM64_CRASH_RESERVE_H
/* Current arm64 boot protocol requires 2MB alignment */
#define CRASH_ALIGN SZ_2M

1
arch/powerpc/Kconfig
View file

@ -691,6 +691,7 @@ config FA_DUMP
bool "Firmware-assisted dump"
depends on PPC64 && (PPC_RTAS || PPC_POWERNV)
select CRASH_CORE
select CRASH_RESERVE
select CRASH_DUMP
help
A robust mechanism to get reliable kernel crash dump with

4
arch/powerpc/mm/nohash/kaslr_booke.c
View file

@ -13,7 +13,7 @@
#include <linux/delay.h>
#include <linux/memblock.h>
#include <linux/libfdt.h>
#include <linux/crash_core.h>
#include <linux/crash_reserve.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <asm/cacheflush.h>
@ -173,7 +173,7 @@ static __init bool overlaps_region(const void *fdt, u32 start,
static void __init get_crash_kernel(void *fdt, unsigned long size)
{
#ifdef CONFIG_CRASH_CORE
#ifdef CONFIG_CRASH_RESERVE
unsigned long long crash_size, crash_base;
int ret;

2
arch/riscv/Kconfig
View file

@ -767,7 +767,7 @@ config ARCH_SUPPORTS_CRASH_DUMP
def_bool y
config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
def_bool CRASH_CORE
def_bool CRASH_RESERVE
config COMPAT
bool "Kernel support for 32-bit U-mode"

4
arch/riscv/include/asm/crash_core.h → arch/riscv/include/asm/crash_reserve.h
View file

@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef _RISCV_CRASH_CORE_H
#define _RISCV_CRASH_CORE_H
#ifndef _RISCV_CRASH_RESERVE_H
#define _RISCV_CRASH_RESERVE_H
#define CRASH_ALIGN PMD_SIZE

2
arch/x86/Kconfig
View file

@ -2106,7 +2106,7 @@ config ARCH_SUPPORTS_CRASH_HOTPLUG
def_bool y
config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
def_bool CRASH_CORE
def_bool CRASH_RESERVE
config PHYSICAL_START
hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)

6
arch/x86/include/asm/crash_core.h → arch/x86/include/asm/crash_reserve.h
View file

@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _X86_CRASH_CORE_H
#define _X86_CRASH_CORE_H
#ifndef _X86_CRASH_RESERVE_H
#define _X86_CRASH_RESERVE_H
/* 16M alignment for crash kernel regions */
#define CRASH_ALIGN SZ_16M
@ -39,4 +39,4 @@ static inline unsigned long crash_low_size_default(void)
#endif
}
#endif /* _X86_CRASH_CORE_H */
#endif /* _X86_CRASH_RESERVE_H */

40
include/linux/crash_core.h
View file

@ -5,14 +5,6 @@
#include <linux/linkage.h>
#include <linux/elfcore.h>
#include <linux/elf.h>
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
#include <asm/crash_core.h>
#endif
/* Location of a reserved region to hold the crash kernel.
*/
extern struct resource crashk_res;
extern struct resource crashk_low_res;
#define CRASH_CORE_NOTE_NAME "CORE"
#define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
@ -87,38 +79,6 @@ Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
void *data, size_t data_len);
void final_note(Elf_Word *buf);
int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
unsigned long long *crash_size, unsigned long long *crash_base,
unsigned long long *low_size, bool *high);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
#ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
#define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20)
#endif
#ifndef CRASH_ALIGN
#define CRASH_ALIGN SZ_2M
#endif
#ifndef CRASH_ADDR_LOW_MAX
#define CRASH_ADDR_LOW_MAX SZ_4G
#endif
#ifndef CRASH_ADDR_HIGH_MAX
#define CRASH_ADDR_HIGH_MAX memblock_end_of_DRAM()
#endif
void __init reserve_crashkernel_generic(char *cmdline,
unsigned long long crash_size,
unsigned long long crash_base,
unsigned long long crash_low_size,
bool high);
#else
static inline void __init reserve_crashkernel_generic(char *cmdline,
unsigned long long crash_size,
unsigned long long crash_base,
unsigned long long crash_low_size,
bool high)
{}
#endif
/* Alignment required for elf header segment */
#define ELF_CORE_HEADER_ALIGN 4096

48
include/linux/crash_reserve.h Normal file
View file

@ -0,0 +1,48 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef LINUX_CRASH_RESERVE_H
#define LINUX_CRASH_RESERVE_H
#include <linux/linkage.h>
#include <linux/elfcore.h>
#include <linux/elf.h>
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
#include <asm/crash_reserve.h>
#endif
/* Location of a reserved region to hold the crash kernel.
*/
extern struct resource crashk_res;
extern struct resource crashk_low_res;
int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
unsigned long long *crash_size, unsigned long long *crash_base,
unsigned long long *low_size, bool *high);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
#ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
#define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20)
#endif
#ifndef CRASH_ALIGN
#define CRASH_ALIGN SZ_2M
#endif
#ifndef CRASH_ADDR_LOW_MAX
#define CRASH_ADDR_LOW_MAX SZ_4G
#endif
#ifndef CRASH_ADDR_HIGH_MAX
#define CRASH_ADDR_HIGH_MAX memblock_end_of_DRAM()
#endif
void __init reserve_crashkernel_generic(char *cmdline,
unsigned long long crash_size,
unsigned long long crash_base,
unsigned long long crash_low_size,
bool high);
#else
static inline void __init reserve_crashkernel_generic(char *cmdline,
unsigned long long crash_size,
unsigned long long crash_base,
unsigned long long crash_low_size,
bool high)
{}
#endif
#endif /* LINUX_CRASH_RESERVE_H */

1
include/linux/kexec.h
View file

@ -16,6 +16,7 @@
#if !defined(__ASSEMBLY__)
#include <linux/crash_core.h>
#include <linux/crash_reserve.h>
#include <asm/io.h>
#include <linux/range.h>

5
kernel/Kconfig.kexec
View file

@ -2,11 +2,15 @@
menu "Kexec and crash features"
config CRASH_RESERVE
bool
config CRASH_CORE
bool
config KEXEC_CORE
select CRASH_CORE
select CRASH_RESERVE
bool
config KEXEC_ELF
@ -96,7 +100,6 @@ config KEXEC_JUMP
config CRASH_DUMP
bool "kernel crash dumps"
depends on ARCH_SUPPORTS_CRASH_DUMP
select CRASH_CORE
select KEXEC_CORE
help
Generate crash dump after being started by kexec.

1
kernel/Makefile
View file

@ -69,6 +69,7 @@ obj-$(CONFIG_KALLSYMS) += kallsyms.o
obj-$(CONFIG_KALLSYMS_SELFTEST) += kallsyms_selftest.o
obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
obj-$(CONFIG_CRASH_CORE) += crash_core.o
obj-$(CONFIG_CRASH_RESERVE) += crash_reserve.o
obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
obj-$(CONFIG_KEXEC) += kexec.o
obj-$(CONFIG_KEXEC_FILE) += kexec_file.o

438
kernel/crash_core.c
View file

@ -34,444 +34,6 @@ u32 *vmcoreinfo_note;
/* trusted vmcoreinfo, e.g. we can make a copy in the crash memory */
static unsigned char *vmcoreinfo_data_safecopy;
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
struct resource crashk_low_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
/*
* 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;
unsigned long long total_mem = system_ram;
/*
* Firmware sometimes reserves some memory regions for its own use,
* so the system memory size is less than the actual physical memory
* size. Work around this by rounding up the total size to 128M,
* which is enough for most test cases.
*/
total_mem = roundup(total_mem, SZ_128M);
/* 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 >= total_mem) {
pr_warn("crashkernel: invalid size\n");
return -EINVAL;
}
/* match ? */
if (total_mem >= start && total_mem < 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;
}
}
} else
pr_info("crashkernel size resulted in zero bytes\n");
return 0;
}
/*
* 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;
}
#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;
}
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);
}
return ck_cmdline;
}
static int __init __parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
const char *suffix)
{
char *first_colon, *first_space;
char *ck_cmdline;
char *name = "crashkernel=";
BUG_ON(!crash_size || !crash_base);
*crash_size = 0;
*crash_base = 0;
ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
if (!ck_cmdline)
return -ENOENT;
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);
}
/*
* That function is the entry point for command line parsing and should be
* called from the arch-specific code.
*
* If crashkernel=,high|low is supported on architecture, non-NULL values
* should be passed to parameters 'low_size' and 'high'.
*/
int __init parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
unsigned long long *low_size,
bool *high)
{
int ret;
/* crashkernel=X[@offset] */
ret = __parse_crashkernel(cmdline, system_ram, crash_size,
crash_base, NULL);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
/*
* If non-NULL 'high' passed in and no normal crashkernel
* setting detected, try parsing crashkernel=,high|low.
*/
if (high && ret == -ENOENT) {
ret = __parse_crashkernel(cmdline, 0, crash_size,
crash_base, suffix_tbl[SUFFIX_HIGH]);
if (ret || !*crash_size)
return -EINVAL;
/*
* crashkernel=Y,low can be specified or not, but invalid value
* is not allowed.
*/
ret = __parse_crashkernel(cmdline, 0, low_size,
crash_base, suffix_tbl[SUFFIX_LOW]);
if (ret == -ENOENT) {
*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
ret = 0;
} else if (ret) {
return ret;
}
*high = true;
}
#endif
if (!*crash_size)
ret = -EINVAL;
return ret;
}
/*
* Add a dummy early_param handler to mark crashkernel= as a known command line
* parameter and suppress incorrect warnings in init/main.c.
*/
static int __init parse_crashkernel_dummy(char *arg)
{
return 0;
}
early_param("crashkernel", parse_crashkernel_dummy);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
static int __init reserve_crashkernel_low(unsigned long long low_size)
{
#ifdef CONFIG_64BIT
unsigned long long low_base;
low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
if (!low_base) {
pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
return -ENOMEM;
}
pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
low_base, low_base + low_size, low_size >> 20);
crashk_low_res.start = low_base;
crashk_low_res.end = low_base + low_size - 1;
#endif
return 0;
}
void __init reserve_crashkernel_generic(char *cmdline,
unsigned long long crash_size,
unsigned long long crash_base,
unsigned long long crash_low_size,
bool high)
{
unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
bool fixed_base = false;
/* User specifies base address explicitly. */
if (crash_base) {
fixed_base = true;
search_base = crash_base;
search_end = crash_base + crash_size;
} else if (high) {
search_base = CRASH_ADDR_LOW_MAX;
search_end = CRASH_ADDR_HIGH_MAX;
}
retry:
crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
search_base, search_end);
if (!crash_base) {
/*
* For crashkernel=size[KMG]@offset[KMG], print out failure
* message if can't reserve the specified region.
*/
if (fixed_base) {
pr_warn("crashkernel reservation failed - memory is in use.\n");
return;
}
/*
* For crashkernel=size[KMG], if the first attempt was for
* low memory, fall back to high memory, the minimum required
* low memory will be reserved later.
*/
if (!high && search_end == CRASH_ADDR_LOW_MAX) {
search_end = CRASH_ADDR_HIGH_MAX;
search_base = CRASH_ADDR_LOW_MAX;
crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
goto retry;
}
/*
* For crashkernel=size[KMG],high, if the first attempt was
* for high memory, fall back to low memory.
*/
if (high && search_end == CRASH_ADDR_HIGH_MAX) {
search_end = CRASH_ADDR_LOW_MAX;
search_base = 0;
goto retry;
}
pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
crash_size);
return;
}
if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
crash_low_size && reserve_crashkernel_low(crash_low_size)) {
memblock_phys_free(crash_base, crash_size);
return;
}
pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
crash_base, crash_base + crash_size, crash_size >> 20);
/*
* The crashkernel memory will be removed from the kernel linear
* map. Inform kmemleak so that it won't try to access it.
*/
kmemleak_ignore_phys(crash_base);
if (crashk_low_res.end)
kmemleak_ignore_phys(crashk_low_res.start);
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
}
static __init int insert_crashkernel_resources(void)
{
if (crashk_res.start < crashk_res.end)
insert_resource(&iomem_resource, &crashk_res);
if (crashk_low_res.start < crashk_low_res.end)
insert_resource(&iomem_resource, &crashk_low_res);
return 0;
}
early_initcall(insert_crashkernel_resources);
#endif
int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
void **addr, unsigned long *sz)
{

464
kernel/crash_reserve.c Normal file
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@ -0,0 +1,464 @@
// 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/kexec.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"
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
struct resource crashk_low_res = {
.name = "Crash kernel",
.start = 0,
.end = 0,
.flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM,
.desc = IORES_DESC_CRASH_KERNEL
};
/*
* 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;
unsigned long long total_mem = system_ram;
/*
* Firmware sometimes reserves some memory regions for its own use,
* so the system memory size is less than the actual physical memory
* size. Work around this by rounding up the total size to 128M,
* which is enough for most test cases.
*/
total_mem = roundup(total_mem, SZ_128M);
/* 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 >= total_mem) {
pr_warn("crashkernel: invalid size\n");
return -EINVAL;
}
/* match ? */
if (total_mem >= start && total_mem < 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;
}
}
} else
pr_info("crashkernel size resulted in zero bytes\n");
return 0;
}
/*
* 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;
}
#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;
}
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);
}
return ck_cmdline;
}
static int __init __parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
const char *suffix)
{
char *first_colon, *first_space;
char *ck_cmdline;
char *name = "crashkernel=";
BUG_ON(!crash_size || !crash_base);
*crash_size = 0;
*crash_base = 0;
ck_cmdline = get_last_crashkernel(cmdline, name, suffix);
if (!ck_cmdline)
return -ENOENT;
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);
}
/*
* That function is the entry point for command line parsing and should be
* called from the arch-specific code.
*
* If crashkernel=,high|low is supported on architecture, non-NULL values
* should be passed to parameters 'low_size' and 'high'.
*/
int __init parse_crashkernel(char *cmdline,
unsigned long long system_ram,
unsigned long long *crash_size,
unsigned long long *crash_base,
unsigned long long *low_size,
bool *high)
{
int ret;
/* crashkernel=X[@offset] */
ret = __parse_crashkernel(cmdline, system_ram, crash_size,
crash_base, NULL);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
/*
* If non-NULL 'high' passed in and no normal crashkernel
* setting detected, try parsing crashkernel=,high|low.
*/
if (high && ret == -ENOENT) {
ret = __parse_crashkernel(cmdline, 0, crash_size,
crash_base, suffix_tbl[SUFFIX_HIGH]);
if (ret || !*crash_size)
return -EINVAL;
/*
* crashkernel=Y,low can be specified or not, but invalid value
* is not allowed.
*/
ret = __parse_crashkernel(cmdline, 0, low_size,
crash_base, suffix_tbl[SUFFIX_LOW]);
if (ret == -ENOENT) {
*low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
ret = 0;
} else if (ret) {
return ret;
}
*high = true;
}
#endif
if (!*crash_size)
ret = -EINVAL;
return ret;
}
/*
* Add a dummy early_param handler to mark crashkernel= as a known command line
* parameter and suppress incorrect warnings in init/main.c.
*/
static int __init parse_crashkernel_dummy(char *arg)
{
return 0;
}
early_param("crashkernel", parse_crashkernel_dummy);
#ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
static int __init reserve_crashkernel_low(unsigned long long low_size)
{
#ifdef CONFIG_64BIT
unsigned long long low_base;
low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX);
if (!low_base) {
pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size);
return -ENOMEM;
}
pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n",
low_base, low_base + low_size, low_size >> 20);
crashk_low_res.start = low_base;
crashk_low_res.end = low_base + low_size - 1;
insert_resource(&iomem_resource, &crashk_low_res);
#endif
return 0;
}
void __init reserve_crashkernel_generic(char *cmdline,
unsigned long long crash_size,
unsigned long long crash_base,
unsigned long long crash_low_size,
bool high)
{
unsigned long long search_end = CRASH_ADDR_LOW_MAX, search_base = 0;
bool fixed_base = false;
/* User specifies base address explicitly. */
if (crash_base) {
fixed_base = true;
search_base = crash_base;
search_end = crash_base + crash_size;
} else if (high) {
search_base = CRASH_ADDR_LOW_MAX;
search_end = CRASH_ADDR_HIGH_MAX;
}
retry:
crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
search_base, search_end);
if (!crash_base) {
/*
* For crashkernel=size[KMG]@offset[KMG], print out failure
* message if can't reserve the specified region.
*/
if (fixed_base) {
pr_warn("crashkernel reservation failed - memory is in use.\n");
return;
}
/*
* For crashkernel=size[KMG], if the first attempt was for
* low memory, fall back to high memory, the minimum required
* low memory will be reserved later.
*/
if (!high && search_end == CRASH_ADDR_LOW_MAX) {
search_end = CRASH_ADDR_HIGH_MAX;
search_base = CRASH_ADDR_LOW_MAX;
crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
goto retry;
}
/*
* For crashkernel=size[KMG],high, if the first attempt was
* for high memory, fall back to low memory.
*/
if (high && search_end == CRASH_ADDR_HIGH_MAX) {
search_end = CRASH_ADDR_LOW_MAX;
search_base = 0;
goto retry;
}
pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
crash_size);
return;
}
if ((crash_base >= CRASH_ADDR_LOW_MAX) &&
crash_low_size && reserve_crashkernel_low(crash_low_size)) {
memblock_phys_free(crash_base, crash_size);
return;
}
pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n",
crash_base, crash_base + crash_size, crash_size >> 20);
/*
* The crashkernel memory will be removed from the kernel linear
* map. Inform kmemleak so that it won't try to access it.
*/
kmemleak_ignore_phys(crash_base);
if (crashk_low_res.end)
kmemleak_ignore_phys(crashk_low_res.start);
crashk_res.start = crash_base;
crashk_res.end = crash_base + crash_size - 1;
}
static __init int insert_crashkernel_resources(void)
{
if (crashk_res.start < crashk_res.end)
insert_resource(&iomem_resource, &crashk_res);
if (crashk_low_res.start < crashk_low_res.end)
insert_resource(&iomem_resource, &crashk_low_res);
return 0;
}
early_initcall(insert_crashkernel_resources);
#endif