From 85fcde402db191b5f222ebfecda653777d7d084e Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Wed, 24 Jan 2024 13:12:41 +0800 Subject: 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 Acked-by: Hari Bathini Cc: Al Viro Cc: Eric W. Biederman Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton --- arch/powerpc/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/powerpc/Kconfig') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index b9fc064d38d2..7f704ae5c5ef 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -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 -- cgit From 443cbaf9e2fdbef7d7cae457434a6cb8a679441b Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Wed, 24 Jan 2024 13:12:42 +0800 Subject: crash: split vmcoreinfo exporting code out from crash_core.c Now move the relevant codes into separate files: kernel/crash_reserve.c, include/linux/crash_reserve.h. And add config item CRASH_RESERVE to control its enabling. And also update the old ifdeffery of CONFIG_CRASH_CORE, including of and config item dependency on CRASH_CORE accordingly. And also do renaming as follows: - arch/xxx/kernel/{crash_core.c => vmcore_info.c} because they are only related to vmcoreinfo exporting on x86, arm64, riscv. And also Remove config item CRASH_CORE, and rely on CONFIG_KEXEC_CORE to decide if build in crash_core.c. [yang.lee@linux.alibaba.com: remove duplicated include in vmcore_info.c] Link: https://lkml.kernel.org/r/20240126005744.16561-1-yang.lee@linux.alibaba.com Link: https://lkml.kernel.org/r/20240124051254.67105-3-bhe@redhat.com Signed-off-by: Baoquan He Signed-off-by: Yang Li Acked-by: Hari Bathini Cc: Al Viro Cc: Eric W. Biederman Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton --- arch/powerpc/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/Kconfig') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 7f704ae5c5ef..495d197c9b27 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -690,7 +690,7 @@ config ARCH_SELECTS_CRASH_DUMP config FA_DUMP bool "Firmware-assisted dump" depends on PPC64 && (PPC_RTAS || PPC_POWERNV) - select CRASH_CORE + select VMCORE_INFO select CRASH_RESERVE select CRASH_DUMP help -- cgit From 2c44b67e2ef345c44095d241530c10cfdd610960 Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Wed, 24 Jan 2024 13:12:43 +0800 Subject: crash: remove dependency of FA_DUMP on CRASH_DUMP In kdump kernel, /proc/vmcore is an elf file mapping the crashed kernel's old memory content. Its elf header is constructed in 1st kernel and passed to kdump kernel via elfcorehdr_addr. Config CRASH_DUMP enables the code of 1st kernel's old memory accessing in different architectures. Currently, config FA_DUMP has dependency on CRASH_DUMP because fadump needs access global variable 'elfcorehdr_addr' to judge if it's in kdump kernel within function is_kdump_kernel(). In the current kernel/crash_dump.c, variable 'elfcorehdr_addr' is defined, and function setup_elfcorehdr() used to parse kernel parameter to fetch the passed value of elfcorehdr_addr. Only for accessing elfcorehdr_addr, FA_DUMP really doesn't have to depends on CRASH_DUMP. To remove the dependency of FA_DUMP on CRASH_DUMP to avoid confusion, rename kernel/crash_dump.c to kernel/elfcorehdr.c, and build it when CONFIG_VMCORE_INFO is ebabled. With this, FA_DUMP doesn't need to depend on CRASH_DUMP. [bhe@redhat.com: power/fadump: make FA_DUMP select CRASH_DUMP] Link: https://lkml.kernel.org/r/Zb8D1ASrgX0qVm9z@MiWiFi-R3L-srv Link: https://lkml.kernel.org/r/20240124051254.67105-4-bhe@redhat.com Signed-off-by: Baoquan He Acked-by: Hari Bathini Cc: Al Viro Cc: Eric W. Biederman Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton --- arch/powerpc/Kconfig | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/powerpc/Kconfig') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 495d197c9b27..a9efaf87966d 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -690,8 +690,6 @@ config ARCH_SELECTS_CRASH_DUMP config FA_DUMP bool "Firmware-assisted dump" depends on PPC64 && (PPC_RTAS || PPC_POWERNV) - select VMCORE_INFO - select CRASH_RESERVE select CRASH_DUMP help A robust mechanism to get reliable kernel crash dump with -- cgit From 086d67ef33ecd07ef58f271bb35c1efd20c5acbf Mon Sep 17 00:00:00 2001 From: Baoquan He Date: Wed, 24 Jan 2024 13:12:48 +0800 Subject: ppc, crash: enforce KEXEC and KEXEC_FILE to select CRASH_DUMP In PowerPC, the crash dumping and kexec reboot share code in arch_kexec_locate_mem_hole(), in which struct crash_mem is used. Here enfoce enforce KEXEC and KEXEC_FILE to select CRASH_DUMP for now. [bhe@redhat.com: fix allnoconfig on ppc] Link: https://lkml.kernel.org/r/ZbJwMyCpz4HDySoo@MiWiFi-R3L-srv Link: https://lkml.kernel.org/r/20240124051254.67105-9-bhe@redhat.com Signed-off-by: Baoquan He Acked-by: Hari Bathini Cc: Al Viro Cc: Eric W. Biederman Cc: Pingfan Liu Cc: Klara Modin Cc: Michael Kelley Cc: Nathan Chancellor Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton --- arch/powerpc/Kconfig | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/powerpc/Kconfig') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index a9efaf87966d..c3b44eba0533 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -608,6 +608,11 @@ config PPC64_SUPPORTS_MEMORY_FAILURE config ARCH_SUPPORTS_KEXEC def_bool PPC_BOOK3S || PPC_E500 || (44x && !SMP) +config ARCH_SELECTS_KEXEC + def_bool y + depends on KEXEC + select CRASH_DUMP + config ARCH_SUPPORTS_KEXEC_FILE def_bool PPC64 @@ -618,6 +623,7 @@ config ARCH_SELECTS_KEXEC_FILE def_bool y depends on KEXEC_FILE select KEXEC_ELF + select CRASH_DUMP select HAVE_IMA_KEXEC if IMA config PPC64_BIG_ENDIAN_ELF_ABI_V2 -- cgit