The kexec and crash kernel options are provided in the common
kernel/Kconfig.kexec. Utilize the common options and provide
the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the
equivalent set of KEXEC and CRASH options.
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
---
arch/arm/Kconfig | 29 ++++-------------------------
1 file changed, 4 insertions(+), 25 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 7a27550ff3c1..1a6a6eb48a15 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1645,20 +1645,8 @@ config XIP_DEFLATED_DATA
copied, saving some precious ROM space. A possible drawback is a
slightly longer boot delay.
-config KEXEC
- bool "Kexec system call (EXPERIMENTAL)"
- depends on (!SMP || PM_SLEEP_SMP)
- depends on MMU
- select KEXEC_CORE
- help
- kexec is a system call that implements the ability to shutdown your
- current kernel, and to start another kernel. It is like a reboot
- but it is independent of the system firmware. And like a reboot
- you can start any kernel with it, not just Linux.
-
- It is an ongoing process to be certain the hardware in a machine
- is properly shutdown, so do not be surprised if this code does not
- initially work for you.
+config ARCH_SUPPORTS_KEXEC
+ def_bool (!SMP || PM_SLEEP_SMP) && MMU
config ATAGS_PROC
bool "Export atags in procfs"
@@ -1668,17 +1656,8 @@ config ATAGS_PROC
Should the atags used to boot the kernel be exported in an "atags"
file in procfs. Useful with kexec.
-config CRASH_DUMP
- bool "Build kdump crash kernel (EXPERIMENTAL)"
- help
- Generate crash dump after being started by kexec. This should
- be normally only set in special crash dump kernels which are
- loaded in the main kernel with kexec-tools into a specially
- reserved region and then later executed after a crash by
- kdump/kexec. The crash dump kernel must be compiled to a
- memory address not used by the main kernel
-
- For more details see Documentation/admin-guide/kdump/kdump.rst
+config ARCH_SUPPORTS_CRASH_DUMP
+ def_bool y
config AUTO_ZRELADDR
bool "Auto calculation of the decompressed kernel image address" if !ARCH_MULTIPLATFORM
--
2.31.1On Wed, Jul 5, 2023, at 16:19, Eric DeVolder wrote: > The kexec and crash kernel options are provided in the common > kernel/Kconfig.kexec. Utilize the common options and provide > the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the > equivalent set of KEXEC and CRASH options. > > Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> > +config ARCH_SUPPORTS_KEXEC > + def_bool (!SMP || PM_SLEEP_SMP) && MMU > > config ATAGS_PROC > bool "Export atags in procfs" > @@ -1668,17 +1656,8 @@ config ATAGS_PROC > Should the atags used to boot the kernel be exported in an "atags" > file in procfs. Useful with kexec. > > -config CRASH_DUMP > - bool "Build kdump crash kernel (EXPERIMENTAL)" > - help > - Generate crash dump after being started by kexec. This should > - be normally only set in special crash dump kernels which are > - loaded in the main kernel with kexec-tools into a specially > - reserved region and then later executed after a crash by > - kdump/kexec. The crash dump kernel must be compiled to a > - memory address not used by the main kernel > - > - For more details see Documentation/admin-guide/kdump/kdump.rst > +config ARCH_SUPPORTS_CRASH_DUMP > + def_bool y > I see this is now in linux-next, and it caused a few randconfig build issues, these never happened in the past: * The #ifdef CONFIG_KEXEC check in arch/arm/include/asm/kexec.h needs to be changed to CONFIG_KEXEC_CORE: include/linux/kexec.h:41:2: error: #error KEXEC_SOURCE_MEMORY_LIMIT not defined same thing on m68k * ARCH_SUPPORTS_CRASH_DUMP needs the same dependency as ARCH_SUPPORTS_KEXEC, otherwise we seem to run into an obscure assembler error building the kdump core on architectures that do not support kdump: /tmp/ccpYl6w9.s:1546: Error: selected processor does not support requested special purpose register -- `mrs r2,cpsr' * Most architectures build machine_kexec.o only when KEXEC is enabled, this also needs to be changed to KEXEC_CORE: --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -59,7 +59,7 @@ obj-$(CONFIG_FUNCTION_TRACER) += entry-ftrace.o obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o patch.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o patch.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o -obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o +obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o # Main staffs in KPROBES are in arch/arm/probes/ . obj-$(CONFIG_KPROBES) += patch.o insn.o obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o Arnd
On 7/5/23 10:05, Arnd Bergmann wrote: > On Wed, Jul 5, 2023, at 16:19, Eric DeVolder wrote: >> The kexec and crash kernel options are provided in the common >> kernel/Kconfig.kexec. Utilize the common options and provide >> the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the >> equivalent set of KEXEC and CRASH options. >> >> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> > >> +config ARCH_SUPPORTS_KEXEC >> + def_bool (!SMP || PM_SLEEP_SMP) && MMU >> >> config ATAGS_PROC >> bool "Export atags in procfs" >> @@ -1668,17 +1656,8 @@ config ATAGS_PROC >> Should the atags used to boot the kernel be exported in an "atags" >> file in procfs. Useful with kexec. >> >> -config CRASH_DUMP >> - bool "Build kdump crash kernel (EXPERIMENTAL)" >> - help >> - Generate crash dump after being started by kexec. This should >> - be normally only set in special crash dump kernels which are >> - loaded in the main kernel with kexec-tools into a specially >> - reserved region and then later executed after a crash by >> - kdump/kexec. The crash dump kernel must be compiled to a >> - memory address not used by the main kernel >> - >> - For more details see Documentation/admin-guide/kdump/kdump.rst >> +config ARCH_SUPPORTS_CRASH_DUMP >> + def_bool y >> > > I see this is now in linux-next, and it caused a few randconfig > build issues, these never happened in the past: Arnd, Thanks for looking at this! I received randconfig errors from Andrew Morton's machinery. When investigating I found that randconfig was able to specify CRASH_DUMP without KEXEC, and that lead to problems. I believe this situation existed prior to this series as well. Specifically CRASH_DUMP does not have a dependency on KEXEC, or select (only s390 has this hole closed). For CRASH_DUMP, this series now selects KEXEC to close this gap, which is what a sane config would have (ie both CRASH_DUMP and KEXEC). Do you think the changes outlined below are still needed? eric > > * The #ifdef CONFIG_KEXEC check in arch/arm/include/asm/kexec.h > needs to be changed to CONFIG_KEXEC_CORE: > > include/linux/kexec.h:41:2: error: #error KEXEC_SOURCE_MEMORY_LIMIT not defined > > same thing on m68k > > * ARCH_SUPPORTS_CRASH_DUMP needs the same dependency as ARCH_SUPPORTS_KEXEC, > otherwise we seem to run into an obscure assembler error building the kdump > core on architectures that do not support kdump: > > /tmp/ccpYl6w9.s:1546: Error: selected processor does not support requested special purpose register -- `mrs r2,cpsr' > > * Most architectures build machine_kexec.o only when KEXEC is enabled, > this also needs to be changed to KEXEC_CORE: > > --- a/arch/arm/kernel/Makefile > +++ b/arch/arm/kernel/Makefile > @@ -59,7 +59,7 @@ obj-$(CONFIG_FUNCTION_TRACER) += entry-ftrace.o > obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o patch.o > obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o patch.o > obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o > -obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o > +obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o > # Main staffs in KPROBES are in arch/arm/probes/ . > obj-$(CONFIG_KPROBES) += patch.o insn.o > obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o > > > Arnd
On Wed, Jul 5, 2023, at 17:22, Eric DeVolder wrote:
> On 7/5/23 10:05, Arnd Bergmann wrote:
>> On Wed, Jul 5, 2023, at 16:19, Eric DeVolder wrote:
>>
>> I see this is now in linux-next, and it caused a few randconfig
>> build issues, these never happened in the past:
>
> Arnd,
> Thanks for looking at this!
>
> I received randconfig errors from Andrew Morton's machinery. When
> investigating I
> found that randconfig was able to specify CRASH_DUMP without KEXEC, and
> that lead
> to problems. I believe this situation existed prior to this series as
> well.
On Arm, there was definitely a bug because one could enable CRASH_DUMP
without enabling KEXEC, but that had no effect at all. I only noticed
the problem testing linux-next because it turned from silently broken
into a build failure
> Specifically CRASH_DUMP does not have a dependency on KEXEC, or select
> (only s390
> has this hole closed).
>
> For CRASH_DUMP, this series now selects KEXEC to close this gap, which is what a
> sane config would have (ie both CRASH_DUMP and KEXEC).
Right, that is the easier way out here.
> Do you think the changes outlined below are still needed?
I think only the first one still applies on arm, you need to ensure
that ARCH_SUPPORTS_CRASH_DUMP has the same dependency as
ARCH_SUPPORTS_KEXEC, or it just depends on ARCH_SUPPORTS_KEXEC.
Arnd
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