[PATCH 2/2] powerpc/fadump: make is_kdump_kernel() return false when fadump is active

Hari Bathini hbathini at linux.ibm.com
Sat Sep 2 05:04:38 AEST 2023

Currently, is_kdump_kernel() returns true in crash dump capture kernel
for both kdump and fadump crash dump capturing methods, as both these
methods set elfcorehdr_addr. Some restrictions enforced for crash dump
capture kernel, based on is_kdump_kernel(), are specifically meant for
kdump case and not desirable for fadump - eg. IO queues restriction in
device drivers. So, define is_kdump_kernel() to return false when f/w
assisted adump is active. For fadump case, is_fadump_active() can be
used for capture kernel specific checks.

Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
 arch/powerpc/include/asm/kexec.h |  8 ++++++--
 arch/powerpc/kernel/crash_dump.c | 12 ++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index a1ddba01e7d1..e1b43aa12175 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -99,10 +99,14 @@ void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_co
 void kexec_copy_flush(struct kimage *image);
-#if defined(CONFIG_CRASH_DUMP) && defined(CONFIG_PPC_RTAS)
+#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 */
 extern const struct kexec_file_ops kexec_elf64_ops;
diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c
index 9a3b85bfc83f..2086fa6cdc25 100644
--- a/arch/powerpc/kernel/crash_dump.c
+++ b/arch/powerpc/kernel/crash_dump.c
@@ -19,6 +19,7 @@
 #include <linux/uio.h>
 #include <asm/rtas.h>
 #include <asm/inst.h>
+#include <asm/fadump.h>
 #ifdef DEBUG
 #include <asm/udbg.h>
@@ -92,6 +93,17 @@ ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
 	return csize;
+ * Return true only when kexec based kernel dump capturing method is used.
+ * This ensures all restritions applied for kdump case are not automatically
+ * applied for fadump case.
+ */
+bool is_kdump_kernel(void)
+	return !is_fadump_active() && elfcorehdr_addr != ELFCORE_ADDR_MAX;
  * The crashkernel region will almost always overlap the RTAS region, so

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