| Message ID | 20230705142004.3605799-4-eric.devolder@oracle.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | refactor Kconfig to consolidate KEXEC and CRASH options | expand |
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: * 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
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
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(-)