powerpc/kexec: split CONFIG_CRASH_DUMP out from CONFIG_KEXEC_CORE

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/[email protected]/
[2] https://lore.kernel.org/all/[email protected]/

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


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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.

---

* No changes in v2.

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

index 23270b16e1db..d33352c2e386 100644
@@ -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

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.

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.

---

* 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(-)

index 904016cf89ea..6d8951e8e966 100644
@@ -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");

2.43.2


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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.

---

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(-)

index 5cf8ad8d7e8e..e377deefa2dc 100644
@@ -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,

index 1dc32a058156..cd8d8883de90 100644
@@ -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;

index 8cb84d46319e..34aef8f753f9 100644
@@ -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

index 693334c20d07..aa81c95c73a4 100644
@@ -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;

index 91e96f5168b7..8e469c4da3f8 100644
@@ -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

index 3ff4411ed496..b8333a49ea5d 100644
@@ -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 */

index 9e1a25398f98..8f14f0581a21 100644
@@ -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

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.

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