[PATCH linux-next v2 0/3] powerpc/kexec: split CONFIG_CRASH_DUMP out from CONFIG_KEXEC_CORE

[PATCH linux-next v2 0/3] powerpc/kexec: split CONFIG_CRASH_DUMP out from CONFIG_KEXEC_CORE

[Hari Bathini]

This patch series is a follow-up to [1] based on discussions at [2]
about additional work needed to get it working on powerpc.

The first patch in the series makes struct crash_mem available with or
without CONFIG_CRASH_DUMP enabled. The next patch moves kdump specific
code for kexec_file_load syscall under CONFIG_CRASH_DUMP and the last
patch splits other kdump specific code under CONFIG_CRASH_DUMP and
removes dependency with CONFIG_CRASH_DUMP for CONFIG_KEXEC_CORE.

[1] https://lore.kernel.org/all/20240124051254.67105-1-bhe@redhat.com/
[2] https://lore.kernel.org/all/9101bb07-70f1-476c-bec9-ec67e9899744@linux.ibm.com/

Changes in v2:
* Fixed a compile error for POWERNV build reported by Sourabh.

Hari Bathini (3):
  kexec/kdump: make struct crash_mem available without CONFIG_CRASH_DUMP
  powerpc/kexec: split CONFIG_KEXEC_FILE and CONFIG_CRASH_DUMP
  powerpc/kdump: Split KEXEC_CORE and CRASH_DUMP dependency

 arch/powerpc/Kconfig                 |   9 +-
 arch/powerpc/include/asm/kexec.h     |  98 +++++-----
 arch/powerpc/kernel/prom.c           |   2 +-
 arch/powerpc/kernel/setup-common.c   |   2 +-
 arch/powerpc/kernel/smp.c            |   4 +-
 arch/powerpc/kexec/Makefile          |   3 +-
 arch/powerpc/kexec/core.c            |   4 +
 arch/powerpc/kexec/elf_64.c          |   4 +-
 arch/powerpc/kexec/file_load_64.c    | 269 ++++++++++++++-------------
 arch/powerpc/platforms/powernv/smp.c |   2 +-
 include/linux/crash_core.h           |  12 +-
 11 files changed, 209 insertions(+), 200 deletions(-)

-- 
2.43.2

[PATCH linux-next v2 1/3] kexec/kdump: make struct crash_mem available without CONFIG_CRASH_DUMP

[Hari Bathini]

struct crash_mem defined under include/linux/crash_core.h represents
a list of memory ranges. While it is used to represent memory ranges
for kdump kernel, it can also be used for other kind of memory ranges.
In fact, KEXEC_FILE_LOAD syscall in powerpc uses this structure to
represent reserved memory ranges and exclude memory ranges needed to
find the right memory regions to load kexec kernel. So, make the
definition of crash_mem structure available for !CONFIG_CRASH_DUMP
case too.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---

* No changes in v2.

 include/linux/crash_core.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 23270b16e1db..d33352c2e386 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -8,6 +8,12 @@
 
 struct kimage;
 
+struct crash_mem {
+	unsigned int max_nr_ranges;
+	unsigned int nr_ranges;
+	struct range ranges[] __counted_by(max_nr_ranges);
+};
+
 #ifdef CONFIG_CRASH_DUMP
 
 int crash_shrink_memory(unsigned long new_size);
@@ -51,12 +57,6 @@ static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
 /* Alignment required for elf header segment */
 #define ELF_CORE_HEADER_ALIGN   4096
 
-struct crash_mem {
-	unsigned int max_nr_ranges;
-	unsigned int nr_ranges;
-	struct range ranges[] __counted_by(max_nr_ranges);
-};
-
 extern int crash_exclude_mem_range(struct crash_mem *mem,
 				   unsigned long long mstart,
 				   unsigned long long mend);
-- 
2.43.2

Re: [PATCH linux-next v2 1/3] kexec/kdump: make struct crash_mem available without CONFIG_CRASH_DUMP

[Baoquan He]

On 02/26/24 at 04:00pm, Hari Bathini wrote:
> struct crash_mem defined under include/linux/crash_core.h represents
> a list of memory ranges. While it is used to represent memory ranges
> for kdump kernel, it can also be used for other kind of memory ranges.
> In fact, KEXEC_FILE_LOAD syscall in powerpc uses this structure to
> represent reserved memory ranges and exclude memory ranges needed to
> find the right memory regions to load kexec kernel. So, make the

We may be able to refactor code to make struct crash_mem only used for
crash handling, or get another data structure for loading kexec kernel.
Anyway, for the time being, this is the simplest way we can take. Thanks
for the work on ppc to make crash split out from the kexec code.

Acked-by: Baoquan He <bhe@redhat.com>

> definition of crash_mem structure available for !CONFIG_CRASH_DUMP
> case too.
> 
> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
> ---
> 
> * No changes in v2.
> 
>  include/linux/crash_core.h | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
> index 23270b16e1db..d33352c2e386 100644
> --- a/include/linux/crash_core.h
> +++ b/include/linux/crash_core.h
> @@ -8,6 +8,12 @@
>  
>  struct kimage;
>  
> +struct crash_mem {
> +	unsigned int max_nr_ranges;
> +	unsigned int nr_ranges;
> +	struct range ranges[] __counted_by(max_nr_ranges);
> +};
> +
>  #ifdef CONFIG_CRASH_DUMP
>  
>  int crash_shrink_memory(unsigned long new_size);
> @@ -51,12 +57,6 @@ static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
>  /* Alignment required for elf header segment */
>  #define ELF_CORE_HEADER_ALIGN   4096
>  
> -struct crash_mem {
> -	unsigned int max_nr_ranges;
> -	unsigned int nr_ranges;
> -	struct range ranges[] __counted_by(max_nr_ranges);
> -};
> -
>  extern int crash_exclude_mem_range(struct crash_mem *mem,
>  				   unsigned long long mstart,
>  				   unsigned long long mend);
> -- 
> 2.43.2
> 

[PATCH linux-next v2 2/3] powerpc/kexec: split CONFIG_KEXEC_FILE and CONFIG_CRASH_DUMP

[Hari Bathini]

CONFIG_KEXEC_FILE does not have to select CONFIG_CRASH_DUMP. Move
some code under CONFIG_CRASH_DUMP to support CONFIG_KEXEC_FILE and
!CONFIG_CRASH_DUMP case.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
---

* No changes in v2.

 arch/powerpc/kexec/elf_64.c       |   4 +-
 arch/powerpc/kexec/file_load_64.c | 269 ++++++++++++++++--------------
 2 files changed, 142 insertions(+), 131 deletions(-)

diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index 904016cf89ea..6d8951e8e966 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -47,7 +47,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
 	if (ret)
 		return ERR_PTR(ret);
 
-	if (image->type == KEXEC_TYPE_CRASH) {
+	if (IS_ENABLED(CONFIG_CRASH_DUMP) && image->type == KEXEC_TYPE_CRASH) {
 		/* min & max buffer values for kdump case */
 		kbuf.buf_min = pbuf.buf_min = crashk_res.start;
 		kbuf.buf_max = pbuf.buf_max =
@@ -70,7 +70,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
 	kexec_dprintk("Loaded purgatory at 0x%lx\n", pbuf.mem);
 
 	/* Load additional segments needed for panic kernel */
-	if (image->type == KEXEC_TYPE_CRASH) {
+	if (IS_ENABLED(CONFIG_CRASH_DUMP) && image->type == KEXEC_TYPE_CRASH) {
 		ret = load_crashdump_segments_ppc64(image, &kbuf);
 		if (ret) {
 			pr_err("Failed to load kdump kernel segments\n");
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index 5b4c5cb23354..1bc65de6174f 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -96,119 +96,6 @@ static int get_exclude_memory_ranges(struct crash_mem **mem_ranges)
 	return ret;
 }
 
-/**
- * get_usable_memory_ranges - Get usable memory ranges. This list includes
- *                            regions like crashkernel, opal/rtas & tce-table,
- *                            that kdump kernel could use.
- * @mem_ranges:               Range list to add the memory ranges to.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int get_usable_memory_ranges(struct crash_mem **mem_ranges)
-{
-	int ret;
-
-	/*
-	 * Early boot failure observed on guests when low memory (first memory
-	 * block?) is not added to usable memory. So, add [0, crashk_res.end]
-	 * instead of [crashk_res.start, crashk_res.end] to workaround it.
-	 * Also, crashed kernel's memory must be added to reserve map to
-	 * avoid kdump kernel from using it.
-	 */
-	ret = add_mem_range(mem_ranges, 0, crashk_res.end + 1);
-	if (ret)
-		goto out;
-
-	ret = add_rtas_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_opal_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_tce_mem_ranges(mem_ranges);
-out:
-	if (ret)
-		pr_err("Failed to setup usable memory ranges\n");
-	return ret;
-}
-
-/**
- * get_crash_memory_ranges - Get crash memory ranges. This list includes
- *                           first/crashing kernel's memory regions that
- *                           would be exported via an elfcore.
- * @mem_ranges:              Range list to add the memory ranges to.
- *
- * Returns 0 on success, negative errno on error.
- */
-static int get_crash_memory_ranges(struct crash_mem **mem_ranges)
-{
-	phys_addr_t base, end;
-	struct crash_mem *tmem;
-	u64 i;
-	int ret;
-
-	for_each_mem_range(i, &base, &end) {
-		u64 size = end - base;
-
-		/* Skip backup memory region, which needs a separate entry */
-		if (base == BACKUP_SRC_START) {
-			if (size > BACKUP_SRC_SIZE) {
-				base = BACKUP_SRC_END + 1;
-				size -= BACKUP_SRC_SIZE;
-			} else
-				continue;
-		}
-
-		ret = add_mem_range(mem_ranges, base, size);
-		if (ret)
-			goto out;
-
-		/* Try merging adjacent ranges before reallocation attempt */
-		if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
-			sort_memory_ranges(*mem_ranges, true);
-	}
-
-	/* Reallocate memory ranges if there is no space to split ranges */
-	tmem = *mem_ranges;
-	if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
-		tmem = realloc_mem_ranges(mem_ranges);
-		if (!tmem)
-			goto out;
-	}
-
-	/* Exclude crashkernel region */
-	ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.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
-	 *        crash, they should actually be backed up just like the
-	 *        first 64K bytes of memory.
-	 */
-	ret = add_rtas_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	ret = add_opal_mem_range(mem_ranges);
-	if (ret)
-		goto out;
-
-	/* create a separate program header for the backup region */
-	ret = add_mem_range(mem_ranges, BACKUP_SRC_START, BACKUP_SRC_SIZE);
-	if (ret)
-		goto out;
-
-	sort_memory_ranges(*mem_ranges, false);
-out:
-	if (ret)
-		pr_err("Failed to setup crash memory ranges\n");
-	return ret;
-}
-
 /**
  * get_reserved_memory_ranges - Get reserve memory ranges. This list includes
  *                              memory regions that should be added to the
@@ -434,6 +321,120 @@ static int locate_mem_hole_bottom_up_ppc64(struct kexec_buf *kbuf,
 	return ret;
 }
 
+#ifdef CONFIG_CRASH_DUMP
+/**
+ * get_usable_memory_ranges - Get usable memory ranges. This list includes
+ *                            regions like crashkernel, opal/rtas & tce-table,
+ *                            that kdump kernel could use.
+ * @mem_ranges:               Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int get_usable_memory_ranges(struct crash_mem **mem_ranges)
+{
+	int ret;
+
+	/*
+	 * Early boot failure observed on guests when low memory (first memory
+	 * block?) is not added to usable memory. So, add [0, crashk_res.end]
+	 * instead of [crashk_res.start, crashk_res.end] to workaround it.
+	 * Also, crashed kernel's memory must be added to reserve map to
+	 * avoid kdump kernel from using it.
+	 */
+	ret = add_mem_range(mem_ranges, 0, crashk_res.end + 1);
+	if (ret)
+		goto out;
+
+	ret = add_rtas_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_opal_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_tce_mem_ranges(mem_ranges);
+out:
+	if (ret)
+		pr_err("Failed to setup usable memory ranges\n");
+	return ret;
+}
+
+/**
+ * get_crash_memory_ranges - Get crash memory ranges. This list includes
+ *                           first/crashing kernel's memory regions that
+ *                           would be exported via an elfcore.
+ * @mem_ranges:              Range list to add the memory ranges to.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+static int get_crash_memory_ranges(struct crash_mem **mem_ranges)
+{
+	phys_addr_t base, end;
+	struct crash_mem *tmem;
+	u64 i;
+	int ret;
+
+	for_each_mem_range(i, &base, &end) {
+		u64 size = end - base;
+
+		/* Skip backup memory region, which needs a separate entry */
+		if (base == BACKUP_SRC_START) {
+			if (size > BACKUP_SRC_SIZE) {
+				base = BACKUP_SRC_END + 1;
+				size -= BACKUP_SRC_SIZE;
+			} else
+				continue;
+		}
+
+		ret = add_mem_range(mem_ranges, base, size);
+		if (ret)
+			goto out;
+
+		/* Try merging adjacent ranges before reallocation attempt */
+		if ((*mem_ranges)->nr_ranges == (*mem_ranges)->max_nr_ranges)
+			sort_memory_ranges(*mem_ranges, true);
+	}
+
+	/* Reallocate memory ranges if there is no space to split ranges */
+	tmem = *mem_ranges;
+	if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
+		tmem = realloc_mem_ranges(mem_ranges);
+		if (!tmem)
+			goto out;
+	}
+
+	/* Exclude crashkernel region */
+	ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.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
+	 *        crash, they should actually be backed up just like the
+	 *        first 64K bytes of memory.
+	 */
+	ret = add_rtas_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	ret = add_opal_mem_range(mem_ranges);
+	if (ret)
+		goto out;
+
+	/* create a separate program header for the backup region */
+	ret = add_mem_range(mem_ranges, BACKUP_SRC_START, BACKUP_SRC_SIZE);
+	if (ret)
+		goto out;
+
+	sort_memory_ranges(*mem_ranges, false);
+out:
+	if (ret)
+		pr_err("Failed to setup crash memory ranges\n");
+	return ret;
+}
+
 /**
  * check_realloc_usable_mem - Reallocate buffer if it can't accommodate entries
  * @um_info:                  Usable memory buffer and ranges info.
@@ -863,6 +864,7 @@ int load_crashdump_segments_ppc64(struct kimage *image,
 
 	return 0;
 }
+#endif
 
 /**
  * setup_purgatory_ppc64 - initialize PPC64 specific purgatory's global
@@ -972,26 +974,14 @@ static unsigned int cpu_node_size(void)
 	return size;
 }
 
-/**
- * kexec_extra_fdt_size_ppc64 - Return the estimated additional size needed to
- *                              setup FDT for kexec/kdump kernel.
- * @image:                      kexec image being loaded.
- *
- * Returns the estimated extra size needed for kexec/kdump kernel FDT.
- */
-unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
+static unsigned int kdump_extra_fdt_size_ppc64(struct kimage *image)
 {
 	unsigned int cpu_nodes, extra_size = 0;
 	struct device_node *dn;
 	u64 usm_entries;
 
-	// Budget some space for the password blob. There's already extra space
-	// for the key name
-	if (plpks_is_available())
-		extra_size += (unsigned int)plpks_get_passwordlen();
-
-	if (image->type != KEXEC_TYPE_CRASH)
-		return extra_size;
+	if (!IS_ENABLED(CONFIG_CRASH_DUMP) || image->type != KEXEC_TYPE_CRASH)
+		return 0;
 
 	/*
 	 * For kdump kernel, account for linux,usable-memory and
@@ -1019,6 +1009,25 @@ unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
 	return extra_size;
 }
 
+/**
+ * kexec_extra_fdt_size_ppc64 - Return the estimated additional size needed to
+ *                              setup FDT for kexec/kdump kernel.
+ * @image:                      kexec image being loaded.
+ *
+ * Returns the estimated extra size needed for kexec/kdump kernel FDT.
+ */
+unsigned int kexec_extra_fdt_size_ppc64(struct kimage *image)
+{
+	unsigned int extra_size = 0;
+
+	// Budget some space for the password blob. There's already extra space
+	// for the key name
+	if (plpks_is_available())
+		extra_size += (unsigned int)plpks_get_passwordlen();
+
+	return extra_size + kdump_extra_fdt_size_ppc64(image);
+}
+
 /**
  * add_node_props - Reads node properties from device node structure and add
  *                  them to fdt.
@@ -1171,6 +1180,7 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
 	struct crash_mem *umem = NULL, *rmem = NULL;
 	int i, nr_ranges, ret;
 
+#ifdef CONFIG_CRASH_DUMP
 	/*
 	 * Restrict memory usage for kdump kernel by setting up
 	 * usable memory ranges and memory reserve map.
@@ -1207,6 +1217,7 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
 			goto out;
 		}
 	}
+#endif
 
 	/* Update cpus nodes information to account hotplug CPUs. */
 	ret =  update_cpus_node(fdt);
@@ -1278,7 +1289,7 @@ int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
 	buf_min = kbuf->buf_min;
 	buf_max = kbuf->buf_max;
 	/* Segments for kdump kernel should be within crashkernel region */
-	if (kbuf->image->type == KEXEC_TYPE_CRASH) {
+	if (IS_ENABLED(CONFIG_CRASH_DUMP) && kbuf->image->type == KEXEC_TYPE_CRASH) {
 		buf_min = (buf_min < crashk_res.start ?
 			   crashk_res.start : buf_min);
 		buf_max = (buf_max > crashk_res.end ?
-- 
2.43.2

[PATCH linux-next v2 3/3] powerpc/kdump: Split KEXEC_CORE and CRASH_DUMP dependency

[Hari Bathini]

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 <hbathini@linux.ibm.com>
---

Changes in v2:
* Fixed a compile error for POWERNV build reported by Sourabh.

 arch/powerpc/Kconfig                 |  9 +--
 arch/powerpc/include/asm/kexec.h     | 98 ++++++++++++++--------------
 arch/powerpc/kernel/prom.c           |  2 +-
 arch/powerpc/kernel/setup-common.c   |  2 +-
 arch/powerpc/kernel/smp.c            |  4 +-
 arch/powerpc/kexec/Makefile          |  3 +-
 arch/powerpc/kexec/core.c            |  4 ++
 arch/powerpc/platforms/powernv/smp.c |  2 +-
 8 files changed, 61 insertions(+), 63 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 5cf8ad8d7e8e..e377deefa2dc 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -607,11 +607,6 @@ 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
 
@@ -622,7 +617,6 @@ 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
@@ -694,8 +688,7 @@ config ARCH_SELECTS_CRASH_DUMP
 
 config FA_DUMP
 	bool "Firmware-assisted dump"
-	depends on PPC64 && (PPC_RTAS || PPC_POWERNV)
-	select CRASH_DUMP
+	depends on CRASH_DUMP && PPC64 && (PPC_RTAS || PPC_POWERNV)
 	help
 	  A robust mechanism to get reliable kernel crash dump with
 	  assistance from firmware. This approach does not use kexec,
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index e1b43aa12175..fdb90e24dc74 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -55,59 +55,18 @@
 typedef void (*crash_shutdown_t)(void);
 
 #ifdef CONFIG_KEXEC_CORE
-
-/*
- * This function is responsible for capturing register states if coming
- * via panic or invoking dump using sysrq-trigger.
- */
-static inline void crash_setup_regs(struct pt_regs *newregs,
-					struct pt_regs *oldregs)
-{
-	if (oldregs)
-		memcpy(newregs, oldregs, sizeof(*newregs));
-	else
-		ppc_save_regs(newregs);
-}
+struct kimage;
+struct pt_regs;
 
 extern void kexec_smp_wait(void);	/* get and clear naca physid, wait for
 					  master to copy new code to 0 */
-extern int crashing_cpu;
-extern void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *));
-extern void crash_ipi_callback(struct pt_regs *);
-extern int crash_wake_offline;
-
-struct kimage;
-struct pt_regs;
 extern void default_machine_kexec(struct kimage *image);
-extern void default_machine_crash_shutdown(struct pt_regs *regs);
-extern int crash_shutdown_register(crash_shutdown_t handler);
-extern int crash_shutdown_unregister(crash_shutdown_t handler);
-
-extern void crash_kexec_prepare(void);
-extern void crash_kexec_secondary(struct pt_regs *regs);
-int __init overlaps_crashkernel(unsigned long start, unsigned long size);
-extern void reserve_crashkernel(void);
 extern void machine_kexec_mask_interrupts(void);
 
-static inline bool kdump_in_progress(void)
-{
-	return crashing_cpu >= 0;
-}
-
 void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_code_buffer,
 			 unsigned long start_address) __noreturn;
-
 void kexec_copy_flush(struct kimage *image);
 
-#if defined(CONFIG_CRASH_DUMP)
-bool is_kdump_kernel(void);
-#define is_kdump_kernel			is_kdump_kernel
-#if defined(CONFIG_PPC_RTAS)
-void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);
-#define crash_free_reserved_phys_range crash_free_reserved_phys_range
-#endif /* CONFIG_PPC_RTAS */
-#endif /* CONFIG_CRASH_DUMP */
-
 #ifdef CONFIG_KEXEC_FILE
 extern const struct kexec_file_ops kexec_elf64_ops;
 
@@ -152,15 +111,56 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
 
 #endif /* CONFIG_KEXEC_FILE */
 
-#else /* !CONFIG_KEXEC_CORE */
-static inline void crash_kexec_secondary(struct pt_regs *regs) { }
+#endif /* CONFIG_KEXEC_CORE */
+
+#ifdef CONFIG_CRASH_RESERVE
+int __init overlaps_crashkernel(unsigned long start, unsigned long size);
+extern void reserve_crashkernel(void);
+#else
+static inline void reserve_crashkernel(void) {}
+static inline int overlaps_crashkernel(unsigned long start, unsigned long size) { return 0; }
+#endif
 
-static inline int overlaps_crashkernel(unsigned long start, unsigned long size)
+#if defined(CONFIG_CRASH_DUMP)
+/*
+ * This function is responsible for capturing register states if coming
+ * via panic or invoking dump using sysrq-trigger.
+ */
+static inline void crash_setup_regs(struct pt_regs *newregs,
+					struct pt_regs *oldregs)
 {
-	return 0;
+	if (oldregs)
+		memcpy(newregs, oldregs, sizeof(*newregs));
+	else
+		ppc_save_regs(newregs);
+}
+
+extern int crashing_cpu;
+extern void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *));
+extern void crash_ipi_callback(struct pt_regs *regs);
+extern int crash_wake_offline;
+
+extern int crash_shutdown_register(crash_shutdown_t handler);
+extern int crash_shutdown_unregister(crash_shutdown_t handler);
+extern void default_machine_crash_shutdown(struct pt_regs *regs);
+
+extern void crash_kexec_prepare(void);
+extern void crash_kexec_secondary(struct pt_regs *regs);
+
+static inline bool kdump_in_progress(void)
+{
+	return crashing_cpu >= 0;
 }
 
-static inline void reserve_crashkernel(void) { ; }
+bool is_kdump_kernel(void);
+#define is_kdump_kernel			is_kdump_kernel
+#if defined(CONFIG_PPC_RTAS)
+void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);
+#define crash_free_reserved_phys_range crash_free_reserved_phys_range
+#endif /* CONFIG_PPC_RTAS */
+
+#else /* !CONFIG_CRASH_DUMP */
+static inline void crash_kexec_secondary(struct pt_regs *regs) { }
 
 static inline int crash_shutdown_register(crash_shutdown_t handler)
 {
@@ -183,7 +183,7 @@ static inline void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 {
 }
 
-#endif /* CONFIG_KEXEC_CORE */
+#endif /* CONFIG_CRASH_DUMP */
 
 #ifdef CONFIG_PPC_BOOK3S_64
 #include <asm/book3s/64/kexec.h>
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 1dc32a058156..cd8d8883de90 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -475,7 +475,7 @@ static int __init early_init_dt_scan_chosen_ppc(unsigned long node,
 		tce_alloc_end = *lprop;
 #endif
 
-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_RESERVE
 	lprop = of_get_flat_dt_prop(node, "linux,crashkernel-base", NULL);
 	if (lprop)
 		crashk_res.start = *lprop;
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 8cb84d46319e..34aef8f753f9 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -110,7 +110,7 @@ int ppc_do_canonicalize_irqs;
 EXPORT_SYMBOL(ppc_do_canonicalize_irqs);
 #endif
 
-#ifdef CONFIG_VMCORE_INFO
+#ifdef CONFIG_CRASH_DUMP
 /* This keeps a track of which one is the crashing cpu. */
 int crashing_cpu = -1;
 #endif
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 693334c20d07..aa81c95c73a4 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -588,7 +588,7 @@ void smp_send_debugger_break(void)
 }
 #endif
 
-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_DUMP
 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 {
 	int cpu;
@@ -631,7 +631,7 @@ void crash_smp_send_stop(void)
 
 	stopped = true;
 
-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_DUMP
 	if (kexec_crash_image) {
 		crash_kexec_prepare();
 		return;
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 91e96f5168b7..8e469c4da3f8 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -3,12 +3,13 @@
 # Makefile for the linux kernel.
 #
 
-obj-y				+= core.o crash.o core_$(BITS).o
+obj-y				+= core.o core_$(BITS).o
 
 obj-$(CONFIG_PPC32)		+= relocate_32.o
 
 obj-$(CONFIG_KEXEC_FILE)	+= file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o
 obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
+obj-$(CONFIG_CRASH_DUMP)	+= crash.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_core_$(BITS).o := n
diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
index 3ff4411ed496..b8333a49ea5d 100644
--- a/arch/powerpc/kexec/core.c
+++ b/arch/powerpc/kexec/core.c
@@ -44,10 +44,12 @@ void machine_kexec_mask_interrupts(void) {
 	}
 }
 
+#ifdef CONFIG_CRASH_DUMP
 void machine_crash_shutdown(struct pt_regs *regs)
 {
 	default_machine_crash_shutdown(regs);
 }
+#endif
 
 void machine_kexec_cleanup(struct kimage *image)
 {
@@ -77,6 +79,7 @@ void machine_kexec(struct kimage *image)
 	for(;;);
 }
 
+#ifdef CONFIG_CRASH_RESERVE
 void __init reserve_crashkernel(void)
 {
 	unsigned long long crash_size, crash_base, total_mem_sz;
@@ -251,3 +254,4 @@ static int __init kexec_setup(void)
 	return 0;
 }
 late_initcall(kexec_setup);
+#endif /* CONFIG_CRASH_RESERVE */
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 9e1a25398f98..8f14f0581a21 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -434,7 +434,7 @@ void __init pnv_smp_init(void)
 	smp_ops = &pnv_smp_ops;
 
 #ifdef CONFIG_HOTPLUG_CPU
-#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_CRASH_DUMP
 	crash_wake_offline = 1;
 #endif
 #endif
-- 
2.43.2

Re: [PATCH linux-next v2 0/3] powerpc/kexec: split CONFIG_CRASH_DUMP out from CONFIG_KEXEC_CORE

[Baoquan He]

On 02/26/24 at 04:00pm, Hari Bathini wrote:
> This patch series is a follow-up to [1] based on discussions at [2]
> about additional work needed to get it working on powerpc.
> 
> The first patch in the series makes struct crash_mem available with or
> without CONFIG_CRASH_DUMP enabled. The next patch moves kdump specific
> code for kexec_file_load syscall under CONFIG_CRASH_DUMP and the last
> patch splits other kdump specific code under CONFIG_CRASH_DUMP and
> removes dependency with CONFIG_CRASH_DUMP for CONFIG_KEXEC_CORE.
> 
> [1] https://lore.kernel.org/all/20240124051254.67105-1-bhe@redhat.com/
> [2] https://lore.kernel.org/all/9101bb07-70f1-476c-bec9-ec67e9899744@linux.ibm.com/
> 
> Changes in v2:
> * Fixed a compile error for POWERNV build reported by Sourabh.
> 
> Hari Bathini (3):
>   kexec/kdump: make struct crash_mem available without CONFIG_CRASH_DUMP
>   powerpc/kexec: split CONFIG_KEXEC_FILE and CONFIG_CRASH_DUMP
>   powerpc/kdump: Split KEXEC_CORE and CRASH_DUMP dependency

I have acked patch 1. And patch 2 and 3 looks good to me, leave these
two to powerpc experts to have a careful reviewing. Thanks for these
great work.


> 
>  arch/powerpc/Kconfig                 |   9 +-
>  arch/powerpc/include/asm/kexec.h     |  98 +++++-----
>  arch/powerpc/kernel/prom.c           |   2 +-
>  arch/powerpc/kernel/setup-common.c   |   2 +-
>  arch/powerpc/kernel/smp.c            |   4 +-
>  arch/powerpc/kexec/Makefile          |   3 +-
>  arch/powerpc/kexec/core.c            |   4 +
>  arch/powerpc/kexec/elf_64.c          |   4 +-
>  arch/powerpc/kexec/file_load_64.c    | 269 ++++++++++++++-------------
>  arch/powerpc/platforms/powernv/smp.c |   2 +-
>  include/linux/crash_core.h           |  12 +-
>  11 files changed, 209 insertions(+), 200 deletions(-)
> 
> -- 
> 2.43.2
> 

Re: [PATCH linux-next v2 0/3] powerpc/kexec: split CONFIG_CRASH_DUMP out from CONFIG_KEXEC_CORE

[Michael Ellerman]

On Mon, 26 Feb 2024 16:00:07 +0530, Hari Bathini wrote:
> This patch series is a follow-up to [1] based on discussions at [2]
> about additional work needed to get it working on powerpc.
> 
> The first patch in the series makes struct crash_mem available with or
> without CONFIG_CRASH_DUMP enabled. The next patch moves kdump specific
> code for kexec_file_load syscall under CONFIG_CRASH_DUMP and the last
> patch splits other kdump specific code under CONFIG_CRASH_DUMP and
> removes dependency with CONFIG_CRASH_DUMP for CONFIG_KEXEC_CORE.
> 
> [...]

Applied to powerpc/next.

[1/3] kexec/kdump: make struct crash_mem available without CONFIG_CRASH_DUMP
      https://git.kernel.org/powerpc/c/56a34d799bfa53064e7b8bd354aacd176aeaecc8
[2/3] powerpc/kexec: split CONFIG_KEXEC_FILE and CONFIG_CRASH_DUMP
      https://git.kernel.org/powerpc/c/33f2cc0a2e90f7177c49559b434191b02efd0cd5
[3/3] powerpc/kdump: Split KEXEC_CORE and CRASH_DUMP dependency
      https://git.kernel.org/powerpc/c/5c4233cc0920cc90787aafe950b90f6c57a35b88

cheers