kernel/arch/powerpc/kexec/core.c, branch linux-rolling-stable

powerpc/kexec/core: use big-endian types for crash variables

2026-03-19T15:14:45Z

[ Upstream commit 20197b967a6a29dab81495f25a988515bda84cfe ] Use explicit word-sized big-endian types for kexec and crash related variables. This makes the endianness unambiguous and avoids type mismatches that trigger sparse warnings. The change addresses sparse warnings like below (seen on both 32-bit and 64-bit builds): CHECK ../arch/powerpc/kexec/core.c sparse: expected unsigned int static [addressable] [toplevel] [usertype] crashk_base sparse: got restricted __be32 [usertype] sparse: warning: incorrect type in assignment (different base types) sparse: expected unsigned int static [addressable] [toplevel] [usertype] crashk_size sparse: got restricted __be32 [usertype] sparse: warning: incorrect type in assignment (different base types) sparse: expected unsigned long long static [addressable] [toplevel] mem_limit sparse: got restricted __be32 [usertype] sparse: warning: incorrect type in assignment (different base types) sparse: expected unsigned int static [addressable] [toplevel] [usertype] kernel_end sparse: got restricted __be32 [usertype] No functional change intended. Fixes: ea961a828fe7 ("powerpc: Fix endian issues in kexec and crash dump code") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202512221405.VHPKPjnp-lkp@intel.com/ Signed-off-by: Sourabh Jain Tested-by: Venkat Rao Bagalkote Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20251224151257.28672-1-sourabhjain@linux.ibm.com Signed-off-by: Sasha Levin

kexec: Include kernel-end even without crashkernel

2025-11-11T09:04:15Z

Certain versions of kexec don't even work without kernel-end being added to the device-tree. Add it even if crash-kernel is disabled. Signed-off-by: Ben Collins Reviewed-by: Sourabh Jain Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/2025042122-inescapable-mandrill-8a5ff2@boujee-and-buff

powerpc/kdump: Add support for crashkernel CMA reservation

2025-11-11T08:41:08Z

Commit 35c18f2933c5 ("Add a new optional ",cma" suffix to the crashkernel= command line option") and commit ab475510e042 ("kdump: implement reserve_crashkernel_cma") added CMA support for kdump crashkernel reservation. Extend crashkernel CMA reservation support to powerpc. The following changes are made to enable CMA reservation on powerpc: - Parse and obtain the CMA reservation size along with other crashkernel parameters - Call reserve_crashkernel_cma() to allocate the CMA region for kdump - Include the CMA-reserved ranges in the usable memory ranges for the kdump kernel to use. - Exclude the CMA-reserved ranges from the crash kernel memory to prevent them from being exported through /proc/vmcore. With the introduction of the CMA crashkernel regions, crash_exclude_mem_range() needs to be called multiple times to exclude both crashk_res and crashk_cma_ranges from the crash memory ranges. To avoid repetitive logic for validating mem_ranges size and handling reallocation when required, this functionality is moved to a new wrapper function crash_exclude_mem_range_guarded(). To ensure proper CMA reservation, reserve_crashkernel_cma() is called after pageblock_order is initialized. Update kernel-parameters.txt to document CMA support for crashkernel on powerpc architecture. Signed-off-by: Sourabh Jain Reviewed-by: Ritesh Harjani (IBM) Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/20251107080334.708028-1-sourabhjain@linux.ibm.com

Add a new optional ",cma" suffix to the crashkernel= command line option

2025-07-20T02:08:22Z

Patch series "kdump: crashkernel reservation from CMA", v5. This series implements a way to reserve additional crash kernel memory using CMA. Currently, all the memory for the crash kernel is not usable by the 1st (production) kernel. It is also unmapped so that it can't be corrupted by the fault that will eventually trigger the crash. This makes sense for the memory actually used by the kexec-loaded crash kernel image and initrd and the data prepared during the load (vmcoreinfo, ...). However, the reserved space needs to be much larger than that to provide enough run-time memory for the crash kernel and the kdump userspace. Estimating the amount of memory to reserve is difficult. Being too careful makes kdump likely to end in OOM, being too generous takes even more memory from the production system. Also, the reservation only allows reserving a single contiguous block (or two with the "low" suffix). I've seen systems where this fails because the physical memory is fragmented. By reserving additional crashkernel memory from CMA, the main crashkernel reservation can be just large enough to fit the kernel and initrd image, minimizing the memory taken away from the production system. Most of the run-time memory for the crash kernel will be memory previously available to userspace in the production system. As this memory is no longer wasted, the reservation can be done with a generous margin, making kdump more reliable. Kernel memory that we need to preserve for dumping is normally not allocated from CMA, unless it is explicitly allocated as movable. Currently this is only the case for memory ballooning and zswap. Such movable memory will be missing from the vmcore. User data is typically not dumped by makedumpfile. When dumping of user data is intended this new CMA reservation cannot be used. There are five patches in this series: The first adds a new ",cma" suffix to the recenly introduced generic crashkernel parsing code. parse_crashkernel() takes one more argument to store the cma reservation size. The second patch implements reserve_crashkernel_cma() which performs the reservation. If the requested size is not available in a single range, multiple smaller ranges will be reserved. The third patch updates Documentation/, explicitly mentioning the potential DMA corruption of the CMA-reserved memory. The fourth patch adds a short delay before booting the kdump kernel, allowing pending DMA transfers to finish. The fifth patch enables the functionality for x86 as a proof of concept. There are just three things every arch needs to do: - call reserve_crashkernel_cma() - include the CMA-reserved ranges in the physical memory map - exclude the CMA-reserved ranges from the memory available through /proc/vmcore by excluding them from the vmcoreinfo PT_LOAD ranges. Adding other architectures is easy and I can do that as soon as this series is merged. With this series applied, specifying crashkernel=100M craskhernel=1G,cma on the command line will make a standard crashkernel reservation of 100M, where kexec will load the kernel and initrd. An additional 1G will be reserved from CMA, still usable by the production system. The crash kernel will have 1.1G memory available. The 100M can be reliably predicted based on the size of the kernel and initrd. The new cma suffix is completely optional. When no crashkernel=size,cma is specified, everything works as before. This patch (of 5): Add a new cma_size parameter to parse_crashkernel(). When not NULL, call __parse_crashkernel to parse the CMA reservation size from "crashkernel=size,cma" and store it in cma_size. Set cma_size to NULL in all calls to parse_crashkernel(). Link: https://lkml.kernel.org/r/aEqnxxfLZMllMC8I@dwarf.suse.cz Link: https://lkml.kernel.org/r/aEqoQckgoTQNULnh@dwarf.suse.cz Signed-off-by: Jiri Bohac Cc: Baoquan He Cc: Dave Young Cc: Donald Dutile Cc: Michal Hocko Cc: Philipp Rudo Cc: Pingfan Liu Cc: Tao Liu Cc: Vivek Goyal Cc: David Hildenbrand Signed-off-by: Andrew Morton

powerpc/crash: use generic crashkernel reservation

2025-03-17T05:30:48Z

Commit 0ab97169aa05 ("crash_core: add generic function to do reservation") added a generic function to reserve crashkernel memory. So let's use the same function on powerpc and remove the architecture-specific code that essentially does the same thing. The generic crashkernel reservation also provides a way to split the crashkernel reservation into high and low memory reservations, which can be enabled for powerpc in the future. Along with moving to the generic crashkernel reservation, the code related to finding the base address for the crashkernel has been separated into its own function name get_crash_base() for better readability and maintainability. Link: https://lkml.kernel.org/r/20250131113830.925179-8-sourabhjain@linux.ibm.com Signed-off-by: Sourabh Jain Reviewed-by: Mahesh Salgaonkar Acked-by: Hari Bathini Cc: Baoquan he Cc: Madhavan Srinivasan Cc: Michael Ellerman Signed-off-by: Andrew Morton

powerpc/crash: preserve user-specified memory limit

2025-03-17T05:30:48Z

Commit 59d58189f3d9 ("crash: fix crash memory reserve exceed system memory bug") fails crashkernel parsing if the crash size is found to be higher than system RAM, which makes the memory_limit adjustment code ineffective due to an early exit from reserve_crashkernel(). Regardless lets not violate the user-specified memory limit by adjusting it. Remove this adjustment to ensure all reservations stay within the limit. Commit f94f5ac07983 ("powerpc/fadump: Don't update the user-specified memory limit") did the same for fadump. Link: https://lkml.kernel.org/r/20250131113830.925179-6-sourabhjain@linux.ibm.com Signed-off-by: Sourabh Jain Reviewed-by: Mahesh Salgaonkar Acked-by: Hari Bathini Cc: Baoquan he Cc: Madhavan Srinivasan Cc: Michael Ellerman Signed-off-by: Andrew Morton

kexec: Consolidate machine_kexec_mask_interrupts() implementation

2024-12-11T19:32:34Z

Consolidate the machine_kexec_mask_interrupts implementation into a common function located in a new file: kernel/irq/kexec.c. This removes duplicate implementations from architecture-specific files in arch/arm, arch/arm64, arch/powerpc, and arch/riscv, reducing code duplication and improving maintainability. The new implementation retains architecture-specific behavior for CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD, which was previously implemented for ARM64. When enabled (currently for ARM64), it clears the active state of interrupts forwarded to virtual machines (VMs) before handling other interrupt masking operations. Signed-off-by: Eliav Farber Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20241204142003.32859-2-farbere@amazon.com

powerpc/kdump: Split KEXEC_CORE and CRASH_DUMP dependency

2024-03-17T02:34:00Z

Remove CONFIG_CRASH_DUMP dependency on CONFIG_KEXEC. CONFIG_KEXEC_CORE was used at places where CONFIG_CRASH_DUMP or CONFIG_CRASH_RESERVE was appropriate. Replace with appropriate #ifdefs to support CONFIG_KEXEC and !CONFIG_CRASH_DUMP configuration option. Also, make CONFIG_FA_DUMP dependent on CONFIG_CRASH_DUMP to avoid unmet dependencies for FA_DUMP with !CONFIG_KEXEC_CORE configuration option. Signed-off-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://msgid.link/20240226103010.589537-4-hbathini@linux.ibm.com

arch, crash: move arch_crash_save_vmcoreinfo() out to file vmcore_info.c

2024-02-24T01:48:25Z

Nathan reported below building error: ===== $ curl -LSso .config https://git.alpinelinux.org/aports/plain/community/linux-edge/config-edge.armv7 $ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- olddefconfig all .. arm-linux-gnueabi-ld: arch/arm/kernel/machine_kexec.o: in function `arch_crash_save_vmcoreinfo': machine_kexec.c:(.text+0x488): undefined reference to `vmcoreinfo_append_str' ==== On architecutres, like arm, s390, ppc, sh, function arch_crash_save_vmcoreinfo() is located in machine_kexec.c and it can only be compiled in when CONFIG_KEXEC_CORE=y. That's not right because arch_crash_save_vmcoreinfo() is used to export arch specific vmcoreinfo. CONFIG_VMCORE_INFO is supposed to control its compiling in. However, CONFIG_VMVCORE_INFO could be independent of CONFIG_KEXEC_CORE, e.g CONFIG_PROC_KCORE=y will select CONFIG_VMVCORE_INFO. Or CONFIG_KEXEC/CONFIG_KEXEC_FILE is set while CONFIG_CRASH_DUMP is not set, it will report linking error. So, on arm, s390, ppc and sh, move arch_crash_save_vmcoreinfo out to a new file vmcore_info.c. Let CONFIG_VMCORE_INFO decide if compiling in arch_crash_save_vmcoreinfo(). [akpm@linux-foundation.org: remove stray newlines at eof] Link: https://lkml.kernel.org/r/20240129135033.157195-3-bhe@redhat.com Signed-off-by: Baoquan He Reported-by: Nathan Chancellor Closes: https://lore.kernel.org/all/20240126045551.GA126645@dev-arch.thelio-3990X/T/#u Cc: Al Viro Cc: Eric W. Biederman Cc: Hari Bathini Cc: Klara Modin Cc: Michael Kelley Cc: Pingfan Liu Cc: Stephen Rothwell Cc: Yang Li Signed-off-by: Andrew Morton

powerpc: add cpu_spec.cpu_features to vmcoreinfo

2023-12-13T11:26:23Z

CPU features can be determined in makedumpfile, using 'cur_cpu_spec.cpu_features'. This provides more data to makedumpfile about the crashed system, and can help in filtering the vmcore accordingly. Signed-off-by: Aditya Gupta Signed-off-by: Michael Ellerman Link: https://msgid.link/20230920105706.853626-2-adityag@linux.ibm.com