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In commit f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for
CRASH_DUMP") we tried to fix a config regression, where CONFIG_CRASH_DUMP
required CONFIG_KEXEC.
However, it was not enough at least for arm64 platforms. While further
testing the patch with our arm64 config I noticed that CONFIG_CRASH_DUMP
is unavailable in menuconfig. This is because CONFIG_CRASH_DUMP still
depends on the new CONFIG_ARCH_SUPPORTS_KEXEC introduced in commit
91506f7e5d ("arm64/kexec: refactor for kernel/Kconfig.kexec") and on
arm64 CONFIG_ARCH_SUPPORTS_KEXEC requires CONFIG_PM_SLEEP_SMP=y, which in
turn requires either CONFIG_SUSPEND=y or CONFIG_HIBERNATION=y neither of
which are set in our config.
Given that we already established that CONFIG_KEXEC (which is a switch for
kexec system call itself) is not required for CONFIG_CRASH_DUMP drop
CONFIG_ARCH_SUPPORTS_KEXEC dependency as well. The arm64 kernel builds
just fine with CONFIG_CRASH_DUMP=y and with both CONFIG_KEXEC=n and
CONFIG_KEXEC_FILE=n after f8ff23429c62 ("kernel/Kconfig.kexec: drop select
of KEXEC for CRASH_DUMP") and this patch are applied given that the
necessary shared bits are included via CONFIG_KEXEC_CORE dependency.
[bhe@redhat.com: don't export some symbols when CONFIG_MMU=n]
Link: https://lkml.kernel.org/r/ZW03ODUKGGhP1ZGU@MiWiFi-R3L-srv
[bhe@redhat.com: riscv, kexec: fix dependency of two items]
Link: https://lkml.kernel.org/r/ZW04G/SKnhbE5mnX@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20231129220409.55006-1-ignat@cloudflare.com
Fixes: 91506f7e5d ("arm64/kexec: refactor for kernel/Kconfig.kexec")
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 6.6+: f8ff234: kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP
Cc: <stable@vger.kernel.org> # 6.6+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
149 lines
5.1 KiB
Plaintext
149 lines
5.1 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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menu "Kexec and crash features"
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config CRASH_CORE
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bool
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config KEXEC_CORE
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select CRASH_CORE
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bool
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config KEXEC_ELF
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bool
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config HAVE_IMA_KEXEC
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bool
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config KEXEC
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bool "Enable kexec system call"
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depends on ARCH_SUPPORTS_KEXEC
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select KEXEC_CORE
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help
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kexec is a system call that implements the ability to shutdown your
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current kernel, and to start another kernel. It is like a reboot
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but it is independent of the system firmware. And like a reboot
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you can start any kernel with it, not just Linux.
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The name comes from the similarity to the exec system call.
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It is an ongoing process to be certain the hardware in a machine
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is properly shutdown, so do not be surprised if this code does not
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initially work for you. As of this writing the exact hardware
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interface is strongly in flux, so no good recommendation can be
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made.
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config KEXEC_FILE
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bool "Enable kexec file based system call"
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depends on ARCH_SUPPORTS_KEXEC_FILE
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select KEXEC_CORE
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help
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This is new version of kexec system call. This system call is
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file based and takes file descriptors as system call argument
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for kernel and initramfs as opposed to list of segments as
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accepted by kexec system call.
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config KEXEC_SIG
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bool "Verify kernel signature during kexec_file_load() syscall"
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depends on ARCH_SUPPORTS_KEXEC_SIG
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depends on KEXEC_FILE
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help
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This option makes the kexec_file_load() syscall check for a valid
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signature of the kernel image. The image can still be loaded without
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a valid signature unless you also enable KEXEC_SIG_FORCE, though if
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there's a signature that we can check, then it must be valid.
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In addition to this option, you need to enable signature
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verification for the corresponding kernel image type being
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loaded in order for this to work.
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config KEXEC_SIG_FORCE
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bool "Require a valid signature in kexec_file_load() syscall"
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depends on ARCH_SUPPORTS_KEXEC_SIG_FORCE
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depends on KEXEC_SIG
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help
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This option makes kernel signature verification mandatory for
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the kexec_file_load() syscall.
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config KEXEC_IMAGE_VERIFY_SIG
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bool "Enable Image signature verification support (ARM)"
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default ARCH_DEFAULT_KEXEC_IMAGE_VERIFY_SIG
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depends on ARCH_SUPPORTS_KEXEC_IMAGE_VERIFY_SIG
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depends on KEXEC_SIG
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depends on EFI && SIGNED_PE_FILE_VERIFICATION
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help
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Enable Image signature verification support.
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config KEXEC_BZIMAGE_VERIFY_SIG
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bool "Enable bzImage signature verification support"
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depends on ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
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depends on KEXEC_SIG
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depends on SIGNED_PE_FILE_VERIFICATION
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select SYSTEM_TRUSTED_KEYRING
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help
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Enable bzImage signature verification support.
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config KEXEC_JUMP
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bool "kexec jump"
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depends on ARCH_SUPPORTS_KEXEC_JUMP
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depends on KEXEC && HIBERNATION
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help
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Jump between original kernel and kexeced kernel and invoke
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code in physical address mode via KEXEC
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config CRASH_DUMP
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bool "kernel crash dumps"
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depends on ARCH_SUPPORTS_CRASH_DUMP
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select CRASH_CORE
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select KEXEC_CORE
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help
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Generate crash dump after being started by kexec.
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This should be normally only set in special crash dump kernels
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which are loaded in the main kernel with kexec-tools into
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a specially reserved region and then later executed after
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a crash by kdump/kexec. The crash dump kernel must be compiled
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to a memory address not used by the main kernel or BIOS using
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PHYSICAL_START, or it must be built as a relocatable image
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(CONFIG_RELOCATABLE=y).
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For more details see Documentation/admin-guide/kdump/kdump.rst
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For s390, this option also enables zfcpdump.
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See also <file:Documentation/arch/s390/zfcpdump.rst>
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config CRASH_HOTPLUG
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bool "Update the crash elfcorehdr on system configuration changes"
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default y
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depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG)
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depends on ARCH_SUPPORTS_CRASH_HOTPLUG
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help
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Enable direct update to the crash elfcorehdr (which contains
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the list of CPUs and memory regions to be dumped upon a crash)
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in response to hot plug/unplug or online/offline of CPUs or
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memory. This is a much more advanced approach than userspace
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attempting that.
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If unsure, say Y.
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config CRASH_MAX_MEMORY_RANGES
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int "Specify the maximum number of memory regions for the elfcorehdr"
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default 8192
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depends on CRASH_HOTPLUG
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help
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For the kexec_file_load() syscall path, specify the maximum number of
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memory regions that the elfcorehdr buffer/segment can accommodate.
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These regions are obtained via walk_system_ram_res(); eg. the
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'System RAM' entries in /proc/iomem.
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This value is combined with NR_CPUS_DEFAULT and multiplied by
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sizeof(Elf64_Phdr) to determine the final elfcorehdr memory buffer/
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segment size.
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The value 8192, for example, covers a (sparsely populated) 1TiB system
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consisting of 128MiB memblocks, while resulting in an elfcorehdr
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memory buffer/segment size under 1MiB. This represents a sane choice
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to accommodate both baremetal and virtual machine configurations.
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For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of
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the computation behind the value provided through the
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/sys/kernel/crash_elfcorehdr_size attribute.
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endmenu
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