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c1ad12ee0e
The cleanup for the CONFIG_KEXEC Kconfig logic accidentally changed the
'depends on CRYPTO=y' dependency to a plain 'depends on CRYPTO', which
causes a link failure when all the crypto support is in a loadable module
and kexec_file support is built-in:
x86_64-linux-ld: vmlinux.o: in function `__x64_sys_kexec_file_load':
(.text+0x32e30a): undefined reference to `crypto_alloc_shash'
x86_64-linux-ld: (.text+0x32e58e): undefined reference to `crypto_shash_update'
x86_64-linux-ld: (.text+0x32e6ee): undefined reference to `crypto_shash_final'
Both s390 and x86 have this problem, while ppc64 and riscv have the
correct dependency already. On riscv, the dependency is only used for the
purgatory, not for the kexec_file code itself, which may be a bit
surprising as it means that with CONFIG_CRYPTO=m, it is possible to enable
KEXEC_FILE but then the purgatory code is silently left out.
Move this into the common Kconfig.kexec file in a way that is correct
everywhere, using the dependency on CRYPTO_SHA256=y only when the
purgatory code is available. This requires reversing the dependency
between ARCH_SUPPORTS_KEXEC_PURGATORY and KEXEC_FILE, but the effect
remains the same, other than making riscv behave like the other ones.
On s390, there is an additional dependency on CRYPTO_SHA256_S390, which
should technically not be required but gives better performance. Remove
this dependency here, noting that it was not present in the initial
Kconfig code but was brought in without an explanation in commit
71406883fd357 ("s390/kexec_file: Add kexec_file_load system call").
[arnd@arndb.de: fix riscv build]
Link: https://lkml.kernel.org/r/67ddd260-d424-4229-a815-e3fcfb864a77@app.fastmail.com
Link: https://lkml.kernel.org/r/20231023110308.1202042-1-arnd@kernel.org
Fixes: 6af5138083005 ("x86/kexec: refactor for kernel/Kconfig.kexec")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Tested-by: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Conor Dooley <conor@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
150 lines
5.1 KiB
Plaintext
150 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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depends on CRYPTO_SHA256=y || !ARCH_SUPPORTS_KEXEC_PURGATORY
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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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