When specifying 'kexec -c -d', kexec_load interface will print loading
information, e.g the regions where kernel/initrd/purgatory/cmdline
are put, the memmap passed to 2nd kernel taken as system RAM ranges,
and printing all contents of struct kexec_segment, etc. These are
very helpful for analyzing or positioning what's happening when
kexec/kdump itself failed. The debugging printing for kexec_load
interface is made in user space utility kexec-tools.
Whereas, with kexec_file_load interface, 'kexec -s -d' print nothing.
Because kexec_file code is mostly implemented in kernel space, and the
debugging printing functionality is missed. It's not convenient when
debugging kexec/kdump loading and jumping with kexec_file_load
interface.
Now add KEXEC_FILE_DEBUG to kexec_file flag to control the debugging
message printing. And add global variable kexec_file_dbg_print and
macro kexec_dprintk() to facilitate the printing.
This is a preparation, later kexec_dprintk() will be used to replace the
existing pr_debug(). Once 'kexec -s -d' is specified, it will print out
kexec/kdump loading information. If '-d' is not specified, it regresses
to pr_debug().
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
---
include/linux/kexec.h | 14 +++++++++++++-
include/uapi/linux/kexec.h | 1 +
kernel/kexec_file.c | 5 +++++
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 8227455192b7..189a6c5bec84 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -264,6 +264,18 @@ arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section,
return -ENOEXEC;
}
#endif
+
+extern bool kexec_file_dbg_print;
+
+#define kexec_dprintk(fmt, args...) \
+ do { \
+ if (kexec_file_dbg_print) \
+ printk(KERN_INFO fmt, ##args); \
+ else \
+ printk(KERN_DEBUG fmt, ##args); \
+ } while (0)
+
+
#endif /* CONFIG_KEXEC_FILE */
#ifdef CONFIG_KEXEC_ELF
@@ -403,7 +415,7 @@ bool kexec_load_permitted(int kexec_image_type);
/* List of defined/legal kexec file flags */
#define KEXEC_FILE_FLAGS (KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
- KEXEC_FILE_NO_INITRAMFS)
+ KEXEC_FILE_NO_INITRAMFS | KEXEC_FILE_DEBUG)
/* flag to track if kexec reboot is in progress */
extern bool kexec_in_progress;
diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h
index 01766dd839b0..c17bb096ea68 100644
--- a/include/uapi/linux/kexec.h
+++ b/include/uapi/linux/kexec.h
@@ -25,6 +25,7 @@
#define KEXEC_FILE_UNLOAD 0x00000001
#define KEXEC_FILE_ON_CRASH 0x00000002
#define KEXEC_FILE_NO_INITRAMFS 0x00000004
+#define KEXEC_FILE_DEBUG 0x00000008
/* These values match the ELF architecture values.
* Unless there is a good reason that should continue to be the case.
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index f9a419cd22d4..4c35500ae40a 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -38,6 +38,8 @@ void set_kexec_sig_enforced(void)
}
#endif
+bool kexec_file_dbg_print;
+
static int kexec_calculate_store_digests(struct kimage *image);
/* Maximum size in bytes for kernel/initrd files. */
@@ -123,6 +125,8 @@ void kimage_file_post_load_cleanup(struct kimage *image)
*/
kfree(image->image_loader_data);
image->image_loader_data = NULL;
+
+ kexec_file_dbg_print = false;
}
#ifdef CONFIG_KEXEC_SIG
@@ -278,6 +282,7 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
if (!image)
return -ENOMEM;
+ kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
image->file_mode = 1;
if (kexec_on_panic) {
--
2.41.0
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