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kexec: split crashkernel reservation code out from crash_core.c 

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
Show 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