Currently, is_kdump_kernel() returns true when elfcorehdr_addr is set.
While elfcorehdr_addr is set for kexec based kernel dump mechanism,
alternate dump capturing methods like fadump [1] also set it to export
the vmcore. is_kdump_kernel() is used to restrict resources in crash
dump capture kernel but such restrictions may not be desirable for
fadump. Allow is_kdump_kernel() to be defined differently for such
scenarios. With this, is_kdump_kernel() could be false while vmcore
is usable. So, introduce is_crashdump_kernel() to return true when
elfcorehdr_addr is set and use it for vmcore related checks.
[1] https://docs.kernel.org/powerpc/firmware-assisted-dump.html
Signed-off-by: Hari Bathini <[email protected]>
---
include/linux/crash_dump.h | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index 0f3a656293b0..1052a0faf0dd 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -50,6 +50,7 @@ void vmcore_cleanup(void);
#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
#endif
+#ifndef is_kdump_kernel
/*
* is_kdump_kernel() checks whether this kernel is booting after a panic of
* previous kernel or not. This is determined by checking if previous kernel
@@ -64,6 +65,19 @@ static inline bool is_kdump_kernel(void)
{
return elfcorehdr_addr != ELFCORE_ADDR_MAX;
}
+#endif
+
+/*
+ * Return true if this is a dump capture kernel, where vmcore needs to be
+ * exported, irrespective of the dump capture mechanism in use.
+ *
+ * Same as is_kdump_kernel() unless arch specific code defines is_kdump_kernel()
+ * differently while supporting other dump capturing mechanisms.
+ */
+static inline bool is_crashdump_kernel(void)
+{
+ return elfcorehdr_addr != ELFCORE_ADDR_MAX;
+}
/* is_vmcore_usable() checks if the kernel is booting after a panic and
* the vmcore region is usable.
@@ -75,7 +89,7 @@ static inline bool is_kdump_kernel(void)
static inline int is_vmcore_usable(void)
{
- return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
+ return is_crashdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
}
/* vmcore_unusable() marks the vmcore as unusable,
@@ -84,7 +98,7 @@ static inline int is_vmcore_usable(void)
static inline void vmcore_unusable(void)
{
- if (is_kdump_kernel())
+ if (is_crashdump_kernel())
elfcorehdr_addr = ELFCORE_ADDR_ERR;
}
--
2.41.0
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 <[email protected]>
---
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
+#endif /* CONFIG_PPC_RTAS */
+#endif /* CONFIG_CRASH_DUMP */
#ifdef CONFIG_KEXEC_FILE
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;
+}
+EXPORT_SYMBOL_GPL(is_kdump_kernel);
+
#ifdef CONFIG_PPC_RTAS
/*
* The crashkernel region will almost always overlap the RTAS region, so
--
2.41.0