On 12/02/26 08:58, Jinjie Ruan wrote:
On 2026/2/10 20:30, Sourabh Jain wrote:
Hello Jinjie,
On 09/02/26 15:29, Jinjie Ruan wrote:
The exclude of crashk_res, crashk_low_res and crashk_cma memory
are almost identical across different architectures, handling them
in the crash core would eliminate a lot of duplication, so do
them in the common code.
And move the size calculation (and the realloc if needed) into the
generic crash core so that:
- New CMA regions or future crash-memory types can automatically
accounted for in crash core;
- Each architecture no longer has to play whack-a-mole with
its private array size.
To achieve the above goal, 4 architecture-specific functions are
introduced:
- arch_get_system_nr_ranges() and arch_prepare_elf64_ram_headers().
The 1st function pre-counts the number of memory ranges, and
the 2st function fill the memory ranges into the cmem->ranges[] array,
and count the actual number of ranges filled. The default
implementation
is consistent with arm64 and loongson.
- arch_crash_exclude_mem_range(). Realloc for powerpc. The default
implementation is crash_exclude_mem_range(), and use
crash_exclude_mem_range_guarded() to implement the arch version
for powerpc.
- arch_get_crash_memory_ranges(). Get crash memory ranges for arch and
the default implementation is generic across x86, arm64, riscv, and
loongson by using the first two arch functions above. powerpc has its
own implementation by calling get_crash_memory_ranges().
Tested on x86, arm64 and riscv with QEMU.
Signed-off-by: Jinjie Ruan <[email protected]>
---
arch/arm64/kernel/machine_kexec_file.c | 47 +--------
arch/loongarch/kernel/machine_kexec_file.c | 45 +-------
arch/powerpc/include/asm/kexec.h | 13 +++
arch/powerpc/kexec/crash.c | 52 ++++++----
arch/powerpc/kexec/file_load_64.c | 17 ++-
arch/powerpc/kexec/ranges.c | 18 +---
arch/riscv/include/asm/kexec.h | 10 ++
arch/riscv/kernel/machine_kexec_file.c | 37 ++-----
arch/x86/include/asm/kexec.h | 10 ++
arch/x86/kernel/crash.c | 104 ++-----------------
include/linux/crash_core.h | 114 +++++++++++++++++++--
kernel/crash_core.c | 71 +++++++++++--
12 files changed, 269 insertions(+), 269 deletions(-)
[...]
extern void crash_ipi_callback(struct pt_regs *regs);
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
index a325c1c02f96..5ade9a853fb0 100644
--- a/arch/powerpc/kexec/crash.c
+++ b/arch/powerpc/kexec/crash.c
@@ -419,30 +419,21 @@ unsigned int arch_crash_get_elfcorehdr_size(void)
return sizeof(struct elfhdr) + (phdr_cnt * sizeof(Elf64_Phdr));
}
-/**
- * update_crash_elfcorehdr() - Recreate the elfcorehdr and replace it
with old
- * elfcorehdr in the kexec segment array.
- * @image: the active struct kimage
- * @mn: struct memory_notify data handler
- */
-static void update_crash_elfcorehdr(struct kimage *image, struct
memory_notify *mn)
+int arch_get_crash_memory_ranges(struct crash_mem **cmem, unsigned
long *nr_mem_ranges,
+ struct kimage *image, struct memory_notify *mn)
{
+ unsigned long base_addr, size;
int ret;
- struct crash_mem *cmem = NULL;
- struct kexec_segment *ksegment;
- void *ptr, *mem, *elfbuf = NULL;
- unsigned long elfsz, memsz, base_addr, size;
- ksegment = &image->segment[image->elfcorehdr_index];
- mem = (void *) ksegment->mem;
- memsz = ksegment->memsz;
-
- ret = get_crash_memory_ranges(&cmem);
+ ret = get_crash_memory_ranges(cmem);
if (ret) {
pr_err("Failed to get crash mem range\n");
- return;
+ return ret;
}
+ if (!image || !mn)
+ return 0;
+
/*
* The hot unplugged memory is part of crash memory ranges,
* remove it here.
@@ -450,14 +441,34 @@ static void update_crash_elfcorehdr(struct
kimage *image, struct memory_notify *
if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) {
base_addr = PFN_PHYS(mn->start_pfn);
size = mn->nr_pages * PAGE_SIZE;
- ret = remove_mem_range(&cmem, base_addr, size);
+ ret = remove_mem_range(cmem, base_addr, size);
I like the overall design for handling crashkernel memory exclusion
in this patch series, especially the way you managed to free the
crash_mem object (mem) in the generic code (crash_prepare_elf64_headers()).
Thanks for the review.
However, the way crash memory is prepared after a memory hotplug
event on powerpc by calling remove_mem_range(), can leave the crash
memory ranges unsorted. This can cause issues in the generic code
when excluding crashkernel memory, because crash_exclude_mem_range()
expects crash_mem to be sorted.
You are absolutely correct.
So I wrote a simple patch to cover this scenario. Including the
patch below as the first patch in this series would be helpful.
https://lore.kernel.org/all/[email protected]/
Thanks for the additional patch. I'll add it as the first patch in the
next revision to ensure crash_mem remains sorted after memory hotplug
events on powerpc.
Thanks you.
Please use the latest version (v2) available here:
https://lore.kernel.org/all/[email protected]/
Regards,
Sourabh Jain
