* [PATCH v5 1/4] powerpc/crash: sort crash memory ranges before preparing elfcorehdr
2026-02-12 10:09 [PATCH v5 0/4] arm64/riscv: Add support for crashkernel CMA reservation Jinjie Ruan
@ 2026-02-12 10:09 ` Jinjie Ruan
2026-02-12 14:43 ` Mike Rapoport
2026-02-12 10:09 ` [PATCH v5 2/4] crash: Exclude crash kernel memory in crash core Jinjie Ruan
` (2 subsequent siblings)
3 siblings, 1 reply; 9+ messages in thread
From: Jinjie Ruan @ 2026-02-12 10:09 UTC (permalink / raw)
To: corbet, skhan, catalin.marinas, will, chenhuacai, kernel, maddy,
mpe, npiggin, chleroy, pjw, palmer, aou, alex, tglx, mingo, bp,
dave.hansen, hpa, akpm, bhe, vgoyal, dyoung, rdunlap, kees, elver,
paulmck, arnd, ruanjinjie, fvdl, thuth, ardb, leitao, rppt,
osandov, cfsworks, sourabhjain, ryan.roberts, tangyouling,
eajames, hbathini, ritesh.list, songshuaishuai, bjorn,
samuel.holland, kevin.brodsky, junhui.liu, vishal.moola, dwmw,
pbonzini, kai.huang, ubizjak, coxu, fuqiang.wang, liaoyuanhong,
brgerst, jbohac, x86, linux-doc, linux-kernel, linux-arm-kernel,
loongarch, linuxppc-dev, linux-riscv, kexec
From: Sourabh Jain <sourabhjain@linux.ibm.com>
During a memory hot-remove event, the elfcorehdr is rebuilt to exclude
the removed memory. While updating the crash memory ranges for this
operation, the crash memory ranges array can become unsorted. This
happens because remove_mem_range() may split a memory range into two
parts and append the higher-address part as a separate range at the end
of the array.
So far, no issues have been observed due to the unsorted crash memory
ranges. However, this could lead to problems once crash memory range
removal is handled by generic code, as introduced in the upcoming
patches in this series.
Currently, powerpc uses a platform-specific function,
remove_mem_range(), to exclude hot-removed memory from the crash memory
ranges. This function performs the same task as the generic
crash_exclude_mem_range() in crash_core.c. The generic helper also
ensures that the crash memory ranges remain sorted. So remove the
redundant powerpc-specific implementation and instead call
crash_exclude_mem_range_guarded() (which internally calls
crash_exclude_mem_range()) to exclude the hot-removed memory ranges.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan he <bhe@redhat.com>
Cc: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Shivang Upadhyay <shivangu@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---
arch/powerpc/include/asm/kexec_ranges.h | 4 +-
arch/powerpc/kexec/crash.c | 5 +-
arch/powerpc/kexec/ranges.c | 87 +------------------------
3 files changed, 7 insertions(+), 89 deletions(-)
diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h
index 14055896cbcb..ad95e3792d10 100644
--- a/arch/powerpc/include/asm/kexec_ranges.h
+++ b/arch/powerpc/include/asm/kexec_ranges.h
@@ -7,7 +7,9 @@
void sort_memory_ranges(struct crash_mem *mrngs, bool merge);
struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges);
int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size);
-int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size);
+int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
+ unsigned long long mstart,
+ unsigned long long mend);
int get_exclude_memory_ranges(struct crash_mem **mem_ranges);
int get_reserved_memory_ranges(struct crash_mem **mem_ranges);
int get_crash_memory_ranges(struct crash_mem **mem_ranges);
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
index a325c1c02f96..898742a5205c 100644
--- a/arch/powerpc/kexec/crash.c
+++ b/arch/powerpc/kexec/crash.c
@@ -431,7 +431,7 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify *
struct crash_mem *cmem = NULL;
struct kexec_segment *ksegment;
void *ptr, *mem, *elfbuf = NULL;
- unsigned long elfsz, memsz, base_addr, size;
+ unsigned long elfsz, memsz, base_addr, size, end;
ksegment = &image->segment[image->elfcorehdr_index];
mem = (void *) ksegment->mem;
@@ -450,7 +450,8 @@ 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);
+ end = base_addr + size - 1;
+ ret = crash_exclude_mem_range_guarded(&cmem, base_addr, end);
if (ret) {
pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n");
goto out;
diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
index 867135560e5c..6c58bcc3e130 100644
--- a/arch/powerpc/kexec/ranges.c
+++ b/arch/powerpc/kexec/ranges.c
@@ -553,7 +553,7 @@ int get_usable_memory_ranges(struct crash_mem **mem_ranges)
#endif /* CONFIG_KEXEC_FILE */
#ifdef CONFIG_CRASH_DUMP
-static int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
+int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
unsigned long long mstart,
unsigned long long mend)
{
@@ -641,89 +641,4 @@ int get_crash_memory_ranges(struct crash_mem **mem_ranges)
pr_err("Failed to setup crash memory ranges\n");
return ret;
}
-
-/**
- * remove_mem_range - Removes the given memory range from the range list.
- * @mem_ranges: Range list to remove the memory range to.
- * @base: Base address of the range to remove.
- * @size: Size of the memory range to remove.
- *
- * (Re)allocates memory, if needed.
- *
- * Returns 0 on success, negative errno on error.
- */
-int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size)
-{
- u64 end;
- int ret = 0;
- unsigned int i;
- u64 mstart, mend;
- struct crash_mem *mem_rngs = *mem_ranges;
-
- if (!size)
- return 0;
-
- /*
- * Memory range are stored as start and end address, use
- * the same format to do remove operation.
- */
- end = base + size - 1;
-
- for (i = 0; i < mem_rngs->nr_ranges; i++) {
- mstart = mem_rngs->ranges[i].start;
- mend = mem_rngs->ranges[i].end;
-
- /*
- * Memory range to remove is not part of this range entry
- * in the memory range list
- */
- if (!(base >= mstart && end <= mend))
- continue;
-
- /*
- * Memory range to remove is equivalent to this entry in the
- * memory range list. Remove the range entry from the list.
- */
- if (base == mstart && end == mend) {
- for (; i < mem_rngs->nr_ranges - 1; i++) {
- mem_rngs->ranges[i].start = mem_rngs->ranges[i+1].start;
- mem_rngs->ranges[i].end = mem_rngs->ranges[i+1].end;
- }
- mem_rngs->nr_ranges--;
- goto out;
- }
- /*
- * Start address of the memory range to remove and the
- * current memory range entry in the list is same. Just
- * move the start address of the current memory range
- * entry in the list to end + 1.
- */
- else if (base == mstart) {
- mem_rngs->ranges[i].start = end + 1;
- goto out;
- }
- /*
- * End address of the memory range to remove and the
- * current memory range entry in the list is same.
- * Just move the end address of the current memory
- * range entry in the list to base - 1.
- */
- else if (end == mend) {
- mem_rngs->ranges[i].end = base - 1;
- goto out;
- }
- /*
- * Memory range to remove is not at the edge of current
- * memory range entry. Split the current memory entry into
- * two half.
- */
- else {
- size = mem_rngs->ranges[i].end - end + 1;
- mem_rngs->ranges[i].end = base - 1;
- ret = add_mem_range(mem_ranges, end + 1, size);
- }
- }
-out:
- return ret;
-}
#endif /* CONFIG_CRASH_DUMP */
--
2.34.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v5 2/4] crash: Exclude crash kernel memory in crash core
2026-02-12 10:09 [PATCH v5 0/4] arm64/riscv: Add support for crashkernel CMA reservation Jinjie Ruan
2026-02-12 10:09 ` [PATCH v5 1/4] powerpc/crash: sort crash memory ranges before preparing elfcorehdr Jinjie Ruan
@ 2026-02-12 10:09 ` Jinjie Ruan
2026-02-12 18:58 ` Mike Rapoport
2026-02-12 10:10 ` [PATCH v5 3/4] arm64: kexec: Add support for crashkernel CMA reservation Jinjie Ruan
2026-02-12 10:10 ` [PATCH v5 4/4] riscv: " Jinjie Ruan
3 siblings, 1 reply; 9+ messages in thread
From: Jinjie Ruan @ 2026-02-12 10:09 UTC (permalink / raw)
To: corbet, skhan, catalin.marinas, will, chenhuacai, kernel, maddy,
mpe, npiggin, chleroy, pjw, palmer, aou, alex, tglx, mingo, bp,
dave.hansen, hpa, akpm, bhe, vgoyal, dyoung, rdunlap, kees, elver,
paulmck, arnd, ruanjinjie, fvdl, thuth, ardb, leitao, rppt,
osandov, cfsworks, sourabhjain, ryan.roberts, tangyouling,
eajames, hbathini, ritesh.list, songshuaishuai, bjorn,
samuel.holland, kevin.brodsky, junhui.liu, vishal.moola, dwmw,
pbonzini, kai.huang, ubizjak, coxu, fuqiang.wang, liaoyuanhong,
brgerst, jbohac, x86, linux-doc, linux-kernel, linux-arm-kernel,
loongarch, linuxppc-dev, linux-riscv, kexec
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.
- 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 <ruanjinjie@huawei.com>
---
arch/arm64/include/asm/kexec.h | 9 +-
arch/arm64/kernel/machine_kexec_file.c | 41 +++-----
arch/loongarch/include/asm/kexec.h | 9 +-
arch/loongarch/kernel/machine_kexec_file.c | 41 +++-----
arch/powerpc/include/asm/kexec.h | 13 +++
arch/powerpc/include/asm/kexec_ranges.h | 3 -
arch/powerpc/kexec/crash.c | 68 ++++++++------
arch/powerpc/kexec/file_load_64.c | 17 ++--
arch/powerpc/kexec/ranges.c | 18 +---
arch/riscv/include/asm/kexec.h | 9 +-
arch/riscv/kernel/machine_kexec_file.c | 37 +++-----
arch/x86/include/asm/kexec.h | 9 ++
arch/x86/kernel/crash.c | 104 +++------------------
include/linux/crash_core.h | 75 +++++++++++++--
kernel/crash_core.c | 85 +++++++++++++++--
15 files changed, 289 insertions(+), 249 deletions(-)
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 892e5bebda95..67f790e3ba14 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -119,6 +119,7 @@ struct kimage_arch {
};
#ifdef CONFIG_KEXEC_FILE
+struct crash_mem;
extern const struct kexec_file_ops kexec_image_ops;
int arch_kimage_file_post_load_cleanup(struct kimage *image);
@@ -128,7 +129,13 @@ extern int load_other_segments(struct kimage *image,
unsigned long kernel_load_addr, unsigned long kernel_size,
char *initrd, unsigned long initrd_len,
char *cmdline);
-#endif
+
+int arch_get_system_nr_ranges(unsigned int *nr_ranges);
+#define arch_get_system_nr_ranges arch_get_system_nr_ranges
+
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem);
+#define arch_prepare_elf64_ram_headers arch_prepare_elf64_ram_headers
+#endif /* CONFIG_KEXEC_FILE */
#endif /* __ASSEMBLER__ */
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 410060ebd86d..506a165117b1 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -40,23 +40,22 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
}
#ifdef CONFIG_CRASH_DUMP
-static int prepare_elf_headers(void **addr, unsigned long *sz)
+int arch_get_system_nr_ranges(unsigned int *nr_ranges)
{
- struct crash_mem *cmem;
- unsigned int nr_ranges;
- int ret;
- u64 i;
phys_addr_t start, end;
+ u64 i;
- nr_ranges = 2; /* for exclusion of crashkernel region */
for_each_mem_range(i, &start, &end)
- nr_ranges++;
+ (*nr_ranges)++;
+
+ return 0;
+}
- cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
- if (!cmem)
- return -ENOMEM;
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
+{
+ phys_addr_t start, end;
+ u64 i;
- cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
for_each_mem_range(i, &start, &end) {
cmem->ranges[cmem->nr_ranges].start = start;
@@ -64,22 +63,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
cmem->nr_ranges++;
}
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (ret)
- goto out;
-
- if (crashk_low_res.end) {
- ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
- if (ret)
- goto out;
- }
-
- ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-
-out:
- kfree(cmem);
- return ret;
+ return 0;
}
#endif
@@ -109,7 +93,8 @@ int load_other_segments(struct kimage *image,
void *headers;
unsigned long headers_sz;
if (image->type == KEXEC_TYPE_CRASH) {
- ret = prepare_elf_headers(&headers, &headers_sz);
+ ret = crash_prepare_elf64_headers(true, &headers, &headers_sz,
+ NULL, NULL, NULL);
if (ret) {
pr_err("Preparing elf core header failed\n");
goto out_err;
diff --git a/arch/loongarch/include/asm/kexec.h b/arch/loongarch/include/asm/kexec.h
index 209fa43222e1..2cb585f25e3f 100644
--- a/arch/loongarch/include/asm/kexec.h
+++ b/arch/loongarch/include/asm/kexec.h
@@ -42,6 +42,7 @@ struct kimage_arch {
};
#ifdef CONFIG_KEXEC_FILE
+struct crash_mem;
extern const struct kexec_file_ops kexec_efi_ops;
extern const struct kexec_file_ops kexec_elf_ops;
@@ -51,7 +52,13 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image);
extern int load_other_segments(struct kimage *image,
unsigned long kernel_load_addr, unsigned long kernel_size,
char *initrd, unsigned long initrd_len, char *cmdline, unsigned long cmdline_len);
-#endif
+
+int arch_get_system_nr_ranges(unsigned int *nr_ranges);
+#define arch_get_system_nr_ranges arch_get_system_nr_ranges
+
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem);
+#define arch_prepare_elf64_ram_headers arch_prepare_elf64_ram_headers
+#endif /* CONFIG_KEXEC_FILE */
typedef void (*do_kexec_t)(unsigned long efi_boot,
unsigned long cmdline_ptr,
diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c
index fb57026f5f25..e8bc7e65d400 100644
--- a/arch/loongarch/kernel/machine_kexec_file.c
+++ b/arch/loongarch/kernel/machine_kexec_file.c
@@ -56,23 +56,22 @@ static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmpl
}
#ifdef CONFIG_CRASH_DUMP
-
-static int prepare_elf_headers(void **addr, unsigned long *sz)
+int arch_get_system_nr_ranges(unsigned int *nr_ranges)
{
- int ret, nr_ranges;
- uint64_t i;
phys_addr_t start, end;
- struct crash_mem *cmem;
+ uint64_t i;
- nr_ranges = 2; /* for exclusion of crashkernel region */
for_each_mem_range(i, &start, &end)
- nr_ranges++;
+ (*nr_ranges)++;
- cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
- if (!cmem)
- return -ENOMEM;
+ return 0;
+}
+
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
+{
+ phys_addr_t start, end;
+ uint64_t i;
- cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
for_each_mem_range(i, &start, &end) {
cmem->ranges[cmem->nr_ranges].start = start;
@@ -80,22 +79,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
cmem->nr_ranges++;
}
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (ret < 0)
- goto out;
-
- if (crashk_low_res.end) {
- ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
- if (ret < 0)
- goto out;
- }
-
- ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-
-out:
- kfree(cmem);
- return ret;
+ return 0;
}
/*
@@ -163,7 +147,8 @@ int load_other_segments(struct kimage *image,
void *headers;
unsigned long headers_sz;
- ret = prepare_elf_headers(&headers, &headers_sz);
+ ret = crash_prepare_elf64_headers(true, &headers, &headers_sz,
+ NULL, NULL, NULL);
if (ret < 0) {
pr_err("Preparing elf core header failed\n");
goto out_err;
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index bd4a6c42a5f3..1cadf34d8050 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -212,6 +212,19 @@ static inline void reset_sprs(void)
}
#endif
+#ifdef CONFIG_CRASH_DUMP
+struct crash_mem;
+struct memory_notify;
+
+int arch_crash_exclude_mem_range(struct crash_mem **mem, unsigned long long mstart,
+ unsigned long long mend);
+#define arch_crash_exclude_mem_range arch_crash_exclude_mem_range
+
+int arch_get_crash_memory_ranges(struct crash_mem **cmem, unsigned long *nr_mem_ranges,
+ struct kimage *image, struct memory_notify *mn);
+#define arch_get_crash_memory_ranges arch_get_crash_memory_ranges
+#endif
+
#endif /* ! __ASSEMBLER__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_KEXEC_H */
diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h
index ad95e3792d10..8489e844b447 100644
--- a/arch/powerpc/include/asm/kexec_ranges.h
+++ b/arch/powerpc/include/asm/kexec_ranges.h
@@ -7,9 +7,6 @@
void sort_memory_ranges(struct crash_mem *mrngs, bool merge);
struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges);
int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size);
-int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
- unsigned long long mstart,
- unsigned long long mend);
int get_exclude_memory_ranges(struct crash_mem **mem_ranges);
int get_reserved_memory_ranges(struct crash_mem **mem_ranges);
int get_crash_memory_ranges(struct crash_mem **mem_ranges);
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
index 898742a5205c..07463f91b2ec 100644
--- a/arch/powerpc/kexec/crash.c
+++ b/arch/powerpc/kexec/crash.c
@@ -399,6 +399,43 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
ppc_md.kexec_cpu_down(1, 0);
}
+int arch_get_crash_memory_ranges(struct crash_mem **cmem, unsigned long *nr_mem_ranges,
+ struct kimage *image, struct memory_notify *mn)
+{
+#ifdef CONFIG_CRASH_HOTPLUG
+ unsigned long base_addr, size, end;
+#endif
+ int ret;
+
+ ret = get_crash_memory_ranges(cmem);
+ if (ret) {
+ pr_err("Failed to get crash mem range\n");
+ return ret;
+ }
+
+ if (!image || !mn)
+ return 0;
+
+ /*
+ * The hot unplugged memory is part of crash memory ranges,
+ * remove it here.
+ */
+#ifdef CONFIG_CRASH_HOTPLUG
+ if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) {
+ base_addr = PFN_PHYS(mn->start_pfn);
+ size = mn->nr_pages * PAGE_SIZE;
+ end = base_addr + size - 1;
+ ret = arch_crash_exclude_mem_range(cmem, base_addr, end);
+ if (ret) {
+ pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n");
+ return ret;
+ }
+ }
+#endif
+
+ return 0;
+}
+
#ifdef CONFIG_CRASH_HOTPLUG
#undef pr_fmt
#define pr_fmt(fmt) "crash hp: " fmt
@@ -427,38 +464,16 @@ unsigned int arch_crash_get_elfcorehdr_size(void)
*/
static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify *mn)
{
- int ret;
- struct crash_mem *cmem = NULL;
- struct kexec_segment *ksegment;
void *ptr, *mem, *elfbuf = NULL;
- unsigned long elfsz, memsz, base_addr, size, end;
+ struct kexec_segment *ksegment;
+ unsigned long elfsz, memsz;
+ int ret;
ksegment = &image->segment[image->elfcorehdr_index];
mem = (void *) ksegment->mem;
memsz = ksegment->memsz;
- ret = get_crash_memory_ranges(&cmem);
- if (ret) {
- pr_err("Failed to get crash mem range\n");
- return;
- }
-
- /*
- * The hot unplugged memory is part of crash memory ranges,
- * remove it here.
- */
- if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) {
- base_addr = PFN_PHYS(mn->start_pfn);
- size = mn->nr_pages * PAGE_SIZE;
- end = base_addr + size - 1;
- ret = crash_exclude_mem_range_guarded(&cmem, base_addr, end);
- if (ret) {
- pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n");
- goto out;
- }
- }
-
- ret = crash_prepare_elf64_headers(cmem, false, &elfbuf, &elfsz);
+ ret = crash_prepare_elf64_headers(false, &elfbuf, &elfsz, NULL, image, mn);
if (ret) {
pr_err("Failed to prepare elf header\n");
goto out;
@@ -487,7 +502,6 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify *
xchg(&kexec_crash_image, image);
}
out:
- kvfree(cmem);
kvfree(elfbuf);
}
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index e7ef8b2a2554..6fe13031236c 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -401,17 +401,17 @@ static void update_backup_region_phdr(struct kimage *image, Elf64_Ehdr *ehdr)
}
}
-static unsigned int kdump_extra_elfcorehdr_size(struct crash_mem *cmem)
+static unsigned int kdump_extra_elfcorehdr_size(unsigned long nr_mem_ranges)
{
#if defined(CONFIG_CRASH_HOTPLUG) && defined(CONFIG_MEMORY_HOTPLUG)
unsigned int extra_sz = 0;
if (CONFIG_CRASH_MAX_MEMORY_RANGES > (unsigned int)PN_XNUM)
pr_warn("Number of Phdrs %u exceeds max\n", CONFIG_CRASH_MAX_MEMORY_RANGES);
- else if (cmem->nr_ranges >= CONFIG_CRASH_MAX_MEMORY_RANGES)
+ else if (nr_mem_ranges >= CONFIG_CRASH_MAX_MEMORY_RANGES)
pr_warn("Configured crash mem ranges may not be enough\n");
else
- extra_sz = (CONFIG_CRASH_MAX_MEMORY_RANGES - cmem->nr_ranges) * sizeof(Elf64_Phdr);
+ extra_sz = (CONFIG_CRASH_MAX_MEMORY_RANGES - nr_mem_ranges) * sizeof(Elf64_Phdr);
return extra_sz;
#endif
@@ -428,17 +428,13 @@ static unsigned int kdump_extra_elfcorehdr_size(struct crash_mem *cmem)
*/
static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)
{
- struct crash_mem *cmem = NULL;
+ unsigned long nr_mem_ranges;
unsigned long headers_sz;
void *headers = NULL;
int ret;
- ret = get_crash_memory_ranges(&cmem);
- if (ret)
- goto out;
-
/* Setup elfcorehdr segment */
- ret = crash_prepare_elf64_headers(cmem, false, &headers, &headers_sz);
+ ret = crash_prepare_elf64_headers(false, &headers, &headers_sz, &nr_mem_ranges, NULL, NULL);
if (ret) {
pr_err("Failed to prepare elf headers for the core\n");
goto out;
@@ -450,7 +446,7 @@ static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)
kbuf->buffer = headers;
kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
kbuf->bufsz = headers_sz;
- kbuf->memsz = headers_sz + kdump_extra_elfcorehdr_size(cmem);
+ kbuf->memsz = headers_sz + kdump_extra_elfcorehdr_size(nr_mem_ranges);
kbuf->top_down = false;
ret = kexec_add_buffer(kbuf);
@@ -463,7 +459,6 @@ static int load_elfcorehdr_segment(struct kimage *image, struct kexec_buf *kbuf)
image->elf_headers_sz = headers_sz;
image->elf_headers = headers;
out:
- kfree(cmem);
return ret;
}
diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
index 6c58bcc3e130..15dfd3b9d538 100644
--- a/arch/powerpc/kexec/ranges.c
+++ b/arch/powerpc/kexec/ranges.c
@@ -553,9 +553,9 @@ int get_usable_memory_ranges(struct crash_mem **mem_ranges)
#endif /* CONFIG_KEXEC_FILE */
#ifdef CONFIG_CRASH_DUMP
-int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
- unsigned long long mstart,
- unsigned long long mend)
+int arch_crash_exclude_mem_range(struct crash_mem **mem_ranges,
+ unsigned long long mstart,
+ unsigned long long mend)
{
struct crash_mem *tmem = *mem_ranges;
@@ -604,18 +604,6 @@ int get_crash_memory_ranges(struct crash_mem **mem_ranges)
sort_memory_ranges(*mem_ranges, true);
}
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_res.start, crashk_res.end);
- if (ret)
- goto out;
-
- for (i = 0; i < crashk_cma_cnt; ++i) {
- ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_cma_ranges[i].start,
- crashk_cma_ranges[i].end);
- if (ret)
- goto out;
- }
-
/*
* FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL
* regions are exported to save their context at the time of
diff --git a/arch/riscv/include/asm/kexec.h b/arch/riscv/include/asm/kexec.h
index b9ee8346cc8c..1eb28d24a5ef 100644
--- a/arch/riscv/include/asm/kexec.h
+++ b/arch/riscv/include/asm/kexec.h
@@ -73,6 +73,13 @@ int load_extra_segments(struct kimage *image, unsigned long kernel_start,
unsigned long kernel_len, char *initrd,
unsigned long initrd_len, char *cmdline,
unsigned long cmdline_len);
-#endif
+
+int arch_get_system_nr_ranges(unsigned int *nr_ranges);
+#define arch_get_system_nr_ranges arch_get_system_nr_ranges
+
+struct crash_mem;
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem);
+#define arch_prepare_elf64_ram_headers arch_prepare_elf64_ram_headers
+#endif /* CONFIG_KEXEC_FILE */
#endif
diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
index dd9d92a96517..2f0e7bbeb2f0 100644
--- a/arch/riscv/kernel/machine_kexec_file.c
+++ b/arch/riscv/kernel/machine_kexec_file.c
@@ -44,6 +44,13 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
return 0;
}
+int arch_get_system_nr_ranges(unsigned int *nr_ranges)
+{
+ walk_system_ram_res(0, -1, nr_ranges, get_nr_ram_ranges_callback);
+
+ return 0;
+}
+
static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
{
struct crash_mem *cmem = arg;
@@ -55,33 +62,10 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
return 0;
}
-static int prepare_elf_headers(void **addr, unsigned long *sz)
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
{
- struct crash_mem *cmem;
- unsigned int nr_ranges;
- int ret;
-
- nr_ranges = 1; /* For exclusion of crashkernel region */
- walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
-
- cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
- if (!cmem)
- return -ENOMEM;
-
- cmem->max_nr_ranges = nr_ranges;
cmem->nr_ranges = 0;
- ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
- if (ret)
- goto out;
-
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (!ret)
- ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-
-out:
- kfree(cmem);
- return ret;
+ return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
}
static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
@@ -273,7 +257,8 @@ int load_extra_segments(struct kimage *image, unsigned long kernel_start,
if (image->type == KEXEC_TYPE_CRASH) {
void *headers;
unsigned long headers_sz;
- ret = prepare_elf_headers(&headers, &headers_sz);
+
+ ret = crash_prepare_elf64_headers(true, &headers, &headers_sz, NULL, NULL, NULL);
if (ret) {
pr_err("Preparing elf core header failed\n");
goto out;
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 5cfb27f26583..3b04d2b4dee6 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -232,6 +232,15 @@ unsigned int arch_crash_get_elfcorehdr_size(void);
#define crash_get_elfcorehdr_size arch_crash_get_elfcorehdr_size
#endif
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_HOTPLUG)
+struct crash_mem;
+int arch_get_system_nr_ranges(unsigned int *nr_ranges);
+#define arch_get_system_nr_ranges arch_get_system_nr_ranges
+
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem);
+#define arch_prepare_elf64_ram_headers arch_prepare_elf64_ram_headers
+#endif
+
#endif /* __ASSEMBLER__ */
#endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 335fd2ee9766..3fbbd518604a 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -152,73 +152,15 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
return 0;
}
-/* Gather all the required information to prepare elf headers for ram regions */
-static struct crash_mem *fill_up_crash_elf_data(void)
+int arch_get_system_nr_ranges(unsigned int *nr_ranges)
{
- unsigned int nr_ranges = 0;
- struct crash_mem *cmem;
+ int ret;
- walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
+ ret = walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
if (!nr_ranges)
- return NULL;
-
- /*
- * Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges
- * may cause range splits. So add extra slots here.
- *
- * Exclusion of low 1M may not cause another range split, because the
- * range of exclude is [0, 1M] and the condition for splitting a new
- * region is that the start, end parameters are both in a certain
- * existing region in cmem and cannot be equal to existing region's
- * start or end. Obviously, the start of [0, 1M] cannot meet this
- * condition.
- *
- * But in order to lest the low 1M could be changed in the future,
- * (e.g. [start, 1M]), add a extra slot.
- */
- nr_ranges += 3 + crashk_cma_cnt;
- cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
- if (!cmem)
- return NULL;
-
- cmem->max_nr_ranges = nr_ranges;
-
- return cmem;
-}
-
-/*
- * Look for any unwanted ranges between mstart, mend and remove them. This
- * might lead to split and split ranges are put in cmem->ranges[] array
- */
-static int elf_header_exclude_ranges(struct crash_mem *cmem)
-{
- int ret = 0;
- int i;
-
- /* Exclude the low 1M because it is always reserved */
- ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
- if (ret)
- return ret;
-
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (ret)
- return ret;
-
- if (crashk_low_res.end)
- ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
- crashk_low_res.end);
- if (ret)
- return ret;
-
- for (i = 0; i < crashk_cma_cnt; ++i) {
- ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start,
- crashk_cma_ranges[i].end);
- if (ret)
- return ret;
- }
+ return -ENOMEM;
- return 0;
+ return ret;
}
static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
@@ -232,35 +174,9 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
return 0;
}
-/* Prepare elf headers. Return addr and size */
-static int prepare_elf_headers(void **addr, unsigned long *sz,
- unsigned long *nr_mem_ranges)
+int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
{
- struct crash_mem *cmem;
- int ret;
-
- cmem = fill_up_crash_elf_data();
- if (!cmem)
- return -ENOMEM;
-
- ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
- if (ret)
- goto out;
-
- /* Exclude unwanted mem ranges */
- ret = elf_header_exclude_ranges(cmem);
- if (ret)
- goto out;
-
- /* Return the computed number of memory ranges, for hotplug usage */
- *nr_mem_ranges = cmem->nr_ranges;
-
- /* By default prepare 64bit headers */
- ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
-
-out:
- vfree(cmem);
- return ret;
+ return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
}
#endif
@@ -418,7 +334,8 @@ int crash_load_segments(struct kimage *image)
.buf_max = ULONG_MAX, .top_down = false };
/* Prepare elf headers and add a segment */
- ret = prepare_elf_headers(&kbuf.buffer, &kbuf.bufsz, &pnum);
+ ret = crash_prepare_elf64_headers(IS_ENABLED(CONFIG_X86_64), &kbuf.buffer,
+ &kbuf.bufsz, &pnum, NULL, NULL);
if (ret)
return ret;
@@ -529,7 +446,8 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
* Create the new elfcorehdr reflecting the changes to CPU and/or
* memory resources.
*/
- if (prepare_elf_headers(&elfbuf, &elfsz, &nr_mem_ranges)) {
+ if (crash_prepare_elf64_headers(IS_ENABLED(CONFIG_X86_64), &elfbuf, &elfsz,
+ &nr_mem_ranges, NULL, NULL)) {
pr_err("unable to create new elfcorehdr");
goto out;
}
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index d35726d6a415..3105d28fd0c6 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -2,11 +2,14 @@
#ifndef LINUX_CRASH_CORE_H
#define LINUX_CRASH_CORE_H
-#include <linux/linkage.h>
#include <linux/elfcore.h>
#include <linux/elf.h>
+#include <linux/kexec.h>
+#include <linux/linkage.h>
+#include <linux/vmalloc.h>
struct kimage;
+struct memory_notify;
struct crash_mem {
unsigned int max_nr_ranges;
@@ -54,6 +57,66 @@ static inline int arch_crash_hotplug_support(struct kimage *image, unsigned long
}
#endif
+extern int crash_exclude_mem_range(struct crash_mem *mem,
+ unsigned long long mstart,
+ unsigned long long mend);
+
+#ifndef arch_crash_exclude_mem_range
+static __always_inline int arch_crash_exclude_mem_range(struct crash_mem **mem_ranges,
+ unsigned long long mstart,
+ unsigned long long mend)
+{
+ return crash_exclude_mem_range(*mem_ranges, mstart, mend);
+}
+#endif
+
+#ifndef arch_get_system_nr_ranges
+static inline int arch_get_system_nr_ranges(unsigned int *nr_ranges)
+{
+ return -EINVAL;
+}
+#endif
+
+#ifndef arch_prepare_elf64_ram_headers
+static inline int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
+{
+ return -EINVAL;
+}
+#endif
+
+#ifndef arch_get_crash_memory_ranges
+static inline int arch_get_crash_memory_ranges(struct crash_mem **cmem,
+ unsigned long *nr_mem_ranges,
+ struct kimage *image,
+ struct memory_notify *mn)
+{
+ unsigned int nr_ranges;
+ int ret;
+
+ /*
+ * Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges
+ * may cause range splits. So add extra slots here.
+ */
+ nr_ranges = 1 + (crashk_low_res.end != 0) + crashk_cma_cnt;
+ ret = arch_get_system_nr_ranges(&nr_ranges);
+ if (ret)
+ return ret;
+
+ *cmem = kvzalloc(struct_size(*cmem, ranges, nr_ranges), GFP_KERNEL);
+ if (!(*cmem))
+ return -ENOMEM;
+
+ (*cmem)->max_nr_ranges = nr_ranges;
+ ret = arch_prepare_elf64_ram_headers(*cmem);
+ if (ret) {
+ kvfree(*cmem);
+ return ret;
+ }
+
+ return 0;
+}
+#endif
+
#ifndef crash_get_elfcorehdr_size
static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
#endif
@@ -61,11 +124,11 @@ static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
/* Alignment required for elf header segment */
#define ELF_CORE_HEADER_ALIGN 4096
-extern int crash_exclude_mem_range(struct crash_mem *mem,
- unsigned long long mstart,
- unsigned long long mend);
-extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
- void **addr, unsigned long *sz);
+extern int crash_prepare_elf64_headers(int need_kernel_map,
+ void **addr, unsigned long *sz,
+ unsigned long *nr_mem_ranges,
+ struct kimage *image,
+ struct memory_notify *mn);
struct kimage;
struct kexec_segment;
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 99dac1aa972a..99a0d6abf88e 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -18,6 +18,7 @@
#include <linux/memblock.h>
#include <linux/kmemleak.h>
#include <linux/crash_core.h>
+#include <linux/crash_reserve.h>
#include <linux/reboot.h>
#include <linux/btf.h>
#include <linux/objtool.h>
@@ -161,19 +162,80 @@ static inline resource_size_t crash_resource_size(const struct resource *res)
return !res->end ? 0 : resource_size(res);
}
+static int crash_exclude_mem_ranges(struct crash_mem *cmem,
+ unsigned long *nr_mem_ranges)
+{
+ int ret, i;
+
+#if defined(CONFIG_X86_64) || defined(CONFIG_X86_32)
+ /*
+ * Exclusion of low 1M may not cause another range split, because the
+ * range of exclude is [0, 1M] and the condition for splitting a new
+ * region is that the start, end parameters are both in a certain
+ * existing region in cmem and cannot be equal to existing region's
+ * start or end. Obviously, the start of [0, 1M] cannot meet this
+ * condition.
+ *
+ * But in order to lest the low 1M could be changed in the future,
+ * (e.g. [start, 1M]), add a extra slot.
+ */
+ cmem->max_nr_ranges++;
+ /* Exclude the low 1M because it is always reserved */
+ ret = arch_crash_exclude_mem_range(&cmem, 0, SZ_1M - 1);
+ if (ret)
+ return ret;
+#endif
+ /* Exclude crashkernel region */
+ ret = arch_crash_exclude_mem_range(&cmem, crashk_res.start, crashk_res.end);
+ if (ret)
+ return ret;
-int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
- void **addr, unsigned long *sz)
+ if (crashk_low_res.end) {
+ ret = arch_crash_exclude_mem_range(&cmem, crashk_low_res.start, crashk_low_res.end);
+ if (ret)
+ return ret;
+ }
+
+ for (i = 0; i < crashk_cma_cnt; ++i) {
+ ret = arch_crash_exclude_mem_range(&cmem, crashk_cma_ranges[i].start,
+ crashk_cma_ranges[i].end);
+ if (ret)
+ return ret;
+ }
+
+ /* Return the computed number of memory ranges, for hotplug usage */
+ if (nr_mem_ranges)
+ *nr_mem_ranges = cmem->nr_ranges;
+
+ return 0;
+}
+
+int crash_prepare_elf64_headers(int need_kernel_map, void **addr,
+ unsigned long *sz, unsigned long *nr_mem_ranges,
+ struct kimage *image, struct memory_notify *mn)
{
- Elf64_Ehdr *ehdr;
- Elf64_Phdr *phdr;
unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
- unsigned char *buf;
- unsigned int cpu, i;
unsigned long long notes_addr;
+ struct crash_mem *mem = NULL;
unsigned long mstart, mend;
+ unsigned int cpu, i;
+ unsigned char *buf;
+ Elf64_Ehdr *ehdr;
+ Elf64_Phdr *phdr;
+ int ret = 0;
+
+ ret = arch_get_crash_memory_ranges(&mem, nr_mem_ranges, image, mn);
+ if (ret)
+ return ret;
+
+ if (!mem)
+ return -ENOMEM;
+
+ ret = crash_exclude_mem_ranges(mem, nr_mem_ranges);
+ if (ret)
+ goto out;
/* extra phdr for vmcoreinfo ELF note */
nr_phdr = nr_cpus + 1;
@@ -192,8 +254,10 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
buf = vzalloc(elf_sz);
- if (!buf)
- return -ENOMEM;
+ if (!buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
ehdr = (Elf64_Ehdr *)buf;
phdr = (Elf64_Phdr *)(ehdr + 1);
@@ -262,7 +326,10 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
*addr = buf;
*sz = elf_sz;
- return 0;
+
+out:
+ kvfree(mem);
+ return ret;
}
/**
--
2.34.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v5 3/4] arm64: kexec: Add support for crashkernel CMA reservation
2026-02-12 10:09 [PATCH v5 0/4] arm64/riscv: Add support for crashkernel CMA reservation Jinjie Ruan
2026-02-12 10:09 ` [PATCH v5 1/4] powerpc/crash: sort crash memory ranges before preparing elfcorehdr Jinjie Ruan
2026-02-12 10:09 ` [PATCH v5 2/4] crash: Exclude crash kernel memory in crash core Jinjie Ruan
@ 2026-02-12 10:10 ` Jinjie Ruan
2026-02-12 10:10 ` [PATCH v5 4/4] riscv: " Jinjie Ruan
3 siblings, 0 replies; 9+ messages in thread
From: Jinjie Ruan @ 2026-02-12 10:10 UTC (permalink / raw)
To: corbet, skhan, catalin.marinas, will, chenhuacai, kernel, maddy,
mpe, npiggin, chleroy, pjw, palmer, aou, alex, tglx, mingo, bp,
dave.hansen, hpa, akpm, bhe, vgoyal, dyoung, rdunlap, kees, elver,
paulmck, arnd, ruanjinjie, fvdl, thuth, ardb, leitao, rppt,
osandov, cfsworks, sourabhjain, ryan.roberts, tangyouling,
eajames, hbathini, ritesh.list, songshuaishuai, bjorn,
samuel.holland, kevin.brodsky, junhui.liu, vishal.moola, dwmw,
pbonzini, kai.huang, ubizjak, coxu, fuqiang.wang, liaoyuanhong,
brgerst, jbohac, x86, linux-doc, linux-kernel, linux-arm-kernel,
loongarch, linuxppc-dev, linux-riscv, kexec
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.
Crash kernel memory reservation wastes production resources if too
large, risks kdump failure if too small, and faces allocation difficulties
on fragmented systems due to contiguous block constraints. The new
CMA-based crashkernel reservation scheme splits the "large fixed
reservation" into a "small fixed region + large CMA dynamic region": the
CMA memory is available to userspace during normal operation to avoid
waste, and is reclaimed for kdump upon crash—saving memory while
improving reliability.
So extend crashkernel CMA reservation support to arm64. The following
changes are made to enable CMA reservation:
- 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 for kdump kernel to use.
- Exclude the CMA-reserved ranges from the crash kernel memory to
prevent them from being exported through /proc/vmcore, which is already
done in the crash core.
Update kernel-parameters.txt to document CMA support for crashkernel on
arm64 architecture.
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
v3:
- Add Acked-by.
v2:
- Free cmem in prepare_elf_headers()
- Add the mtivation.
---
Documentation/admin-guide/kernel-parameters.txt | 2 +-
arch/arm64/kernel/machine_kexec_file.c | 6 ++++++
arch/arm64/mm/init.c | 5 +++--
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index ef1ba922dc60..a2c7c22c60e4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1121,7 +1121,7 @@ Kernel parameters
It will be ignored when crashkernel=X,high is not used
or memory reserved is below 4G.
crashkernel=size[KMG],cma
- [KNL, X86, ppc] Reserve additional crash kernel memory from
+ [KNL, X86, ARM64, ppc] Reserve additional crash kernel memory from
CMA. This reservation is usable by the first system's
userspace memory and kernel movable allocations (memory
balloon, zswap). Pages allocated from this memory range
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 506a165117b1..474b15eefb62 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -63,6 +63,12 @@ int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
cmem->nr_ranges++;
}
+ for (i = 0; i < crashk_cma_cnt; i++) {
+ cmem->ranges[cmem->nr_ranges].start = crashk_cma_ranges[i].start;
+ cmem->ranges[cmem->nr_ranges].end = crashk_cma_ranges[i].end;
+ cmem->nr_ranges++;
+ }
+
return 0;
}
#endif
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 524d34a0e921..28165d94af08 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -96,8 +96,8 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit;
static void __init arch_reserve_crashkernel(void)
{
+ unsigned long long crash_base, crash_size, cma_size = 0;
unsigned long long low_size = 0;
- unsigned long long crash_base, crash_size;
bool high = false;
int ret;
@@ -106,11 +106,12 @@ static void __init arch_reserve_crashkernel(void)
ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
&crash_size, &crash_base,
- &low_size, NULL, &high);
+ &low_size, &cma_size, &high);
if (ret)
return;
reserve_crashkernel_generic(crash_size, crash_base, low_size, high);
+ reserve_crashkernel_cma(cma_size);
}
static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit)
--
2.34.1
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v5 4/4] riscv: kexec: Add support for crashkernel CMA reservation
2026-02-12 10:09 [PATCH v5 0/4] arm64/riscv: Add support for crashkernel CMA reservation Jinjie Ruan
` (2 preceding siblings ...)
2026-02-12 10:10 ` [PATCH v5 3/4] arm64: kexec: Add support for crashkernel CMA reservation Jinjie Ruan
@ 2026-02-12 10:10 ` Jinjie Ruan
2026-02-13 3:10 ` Paul Walmsley
3 siblings, 1 reply; 9+ messages in thread
From: Jinjie Ruan @ 2026-02-12 10:10 UTC (permalink / raw)
To: corbet, skhan, catalin.marinas, will, chenhuacai, kernel, maddy,
mpe, npiggin, chleroy, pjw, palmer, aou, alex, tglx, mingo, bp,
dave.hansen, hpa, akpm, bhe, vgoyal, dyoung, rdunlap, kees, elver,
paulmck, arnd, ruanjinjie, fvdl, thuth, ardb, leitao, rppt,
osandov, cfsworks, sourabhjain, ryan.roberts, tangyouling,
eajames, hbathini, ritesh.list, songshuaishuai, bjorn,
samuel.holland, kevin.brodsky, junhui.liu, vishal.moola, dwmw,
pbonzini, kai.huang, ubizjak, coxu, fuqiang.wang, liaoyuanhong,
brgerst, jbohac, x86, linux-doc, linux-kernel, linux-arm-kernel,
loongarch, linuxppc-dev, linux-riscv, kexec
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. This allows the kernel to dynamically allocate
contiguous memory for crash dumping when needed, rather than permanently
reserving a fixed region at boot time.
So extend crashkernel CMA reservation support to riscv. The following
changes are made to enable CMA reservation:
- 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 for kdump kernel to use.
- Exclude the CMA-reserved ranges from the crash kernel memory to
prevent them from being exported through /proc/vmcore, which is already
done in the crash core.
Update kernel-parameters.txt to document CMA support for crashkernel on
riscv architecture.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++--------
arch/riscv/kernel/machine_kexec_file.c | 14 +++++++++++++-
arch/riscv/mm/init.c | 5 +++--
3 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a2c7c22c60e4..037002b5b867 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1121,14 +1121,14 @@ Kernel parameters
It will be ignored when crashkernel=X,high is not used
or memory reserved is below 4G.
crashkernel=size[KMG],cma
- [KNL, X86, ARM64, ppc] Reserve additional crash kernel memory from
- CMA. This reservation is usable by the first system's
- userspace memory and kernel movable allocations (memory
- balloon, zswap). Pages allocated from this memory range
- will not be included in the vmcore so this should not
- be used if dumping of userspace memory is intended and
- it has to be expected that some movable kernel pages
- may be missing from the dump.
+ [KNL, X86, ARM64, RISCV, ppc] Reserve additional crash
+ kernel memory from CMA. This reservation is usable by
+ the first system's userspace memory and kernel movable
+ allocations (memory balloon, zswap). Pages allocated
+ from this memory range will not be included in the vmcore
+ so this should not be used if dumping of userspace memory
+ is intended and it has to be expected that some movable
+ kernel pages may be missing from the dump.
A standard crashkernel reservation, as described above,
is still needed to hold the crash kernel and initrd.
diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
index 2f0e7bbeb2f0..bc10ff157cf0 100644
--- a/arch/riscv/kernel/machine_kexec_file.c
+++ b/arch/riscv/kernel/machine_kexec_file.c
@@ -64,8 +64,20 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
int arch_prepare_elf64_ram_headers(struct crash_mem *cmem)
{
+ int ret, i;
+
cmem->nr_ranges = 0;
- return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
+ ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < crashk_cma_cnt; i++) {
+ cmem->ranges[cmem->nr_ranges].start = crashk_cma_ranges[i].start;
+ cmem->ranges[cmem->nr_ranges].end = crashk_cma_ranges[i].end;
+ cmem->nr_ranges++;
+ }
+
+ return 0;
}
static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index addb8a9305be..074d2d5f79ee 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -1404,7 +1404,7 @@ static inline void setup_vm_final(void)
*/
static void __init arch_reserve_crashkernel(void)
{
- unsigned long long low_size = 0;
+ unsigned long long low_size = 0, cma_size = 0;
unsigned long long crash_base, crash_size;
bool high = false;
int ret;
@@ -1414,11 +1414,12 @@ static void __init arch_reserve_crashkernel(void)
ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
&crash_size, &crash_base,
- &low_size, NULL, &high);
+ &low_size, &cma_size, &high);
if (ret)
return;
reserve_crashkernel_generic(crash_size, crash_base, low_size, high);
+ reserve_crashkernel_cma(cma_size);
}
void __init paging_init(void)
--
2.34.1
^ permalink raw reply related [flat|nested] 9+ messages in thread