Re: [PATCH v2 2/4] kexec: add kexec_core flag to control debug printing

[Qiang Ma]

在 2025/11/5 11:09, Baoquan He 写道:

On 11/03/25 at 02:34pm, Qiang Ma wrote:

The commit a85ee18c7900 ("kexec_file: print out debugging message
if required") has added general code printing in kexec_file_load(),
but not in kexec_load().

Since kexec_load and kexec_file_load are not triggered
simultaneously, we can unify the debug flag of kexec and kexec_file
as kexec_core_dbg_print.

After reconsidering this, I regret calling it kexec_core_dbg_print.
That sounds a printing only happening in kexec_core. Maybe
kexec_dbg_print is better. Because here kexec refers to a generic
concept, but not limited to kexec_load interface only. Just my personal
thinking.

This sounds reasonable. The next version will be renamed kexec_dbg_print.

Other than the naming, the whole patch looks good to me. Thanks.

Next, we need to do four things:

1. rename kexec_file_dbg_print to kexec_core_dbg_print
2. Add KEXEC_DEBUG
3. Initialize kexec_core_dbg_print for kexec
4. Set the reset of kexec_file_dbg_print to kimage_free

Signed-off-by: Qiang Ma <maqia...@uniontech.com>
---
  include/linux/kexec.h      | 9 +++++----
  include/uapi/linux/kexec.h | 1 +
  kernel/kexec.c             | 1 +
  kernel/kexec_core.c        | 4 +++-
  kernel/kexec_file.c        | 4 +---
  5 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index ff7e231b0485..cad8b5c362af 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -455,10 +455,11 @@ bool kexec_load_permitted(int kexec_image_type);

/* List of defined/legal kexec flags */

  #ifndef CONFIG_KEXEC_JUMP
-#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR | 
KEXEC_CRASH_HOTPLUG_SUPPORT)
+#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR | 
KEXEC_CRASH_HOTPLUG_SUPPORT | \
+                       KEXEC_DEBUG)
  #else
  #define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | 
KEXEC_UPDATE_ELFCOREHDR | \
-                       KEXEC_CRASH_HOTPLUG_SUPPORT)
+                       KEXEC_CRASH_HOTPLUG_SUPPORT | KEXEC_DEBUG)
  #endif

/* List of defined/legal kexec file flags */

@@ -525,10 +526,10 @@ static inline int arch_kexec_post_alloc_pages(void 
*vaddr, unsigned int pages, g
  static inline void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) 
{ }
  #endif

-extern bool kexec_file_dbg_print;

+extern bool kexec_core_dbg_print;

#define kexec_dprintk(fmt, arg...) \

-        do { if (kexec_file_dbg_print) pr_info(fmt, ##arg); } while (0)
+       do { if (kexec_core_dbg_print) pr_info(fmt, ##arg); } while (0)

extern void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size);

  extern void kimage_unmap_segment(void *buffer);
diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h
index 55749cb0b81d..819c600af125 100644
--- a/include/uapi/linux/kexec.h
+++ b/include/uapi/linux/kexec.h
@@ -14,6 +14,7 @@
  #define KEXEC_PRESERVE_CONTEXT        0x00000002
  #define KEXEC_UPDATE_ELFCOREHDR       0x00000004
  #define KEXEC_CRASH_HOTPLUG_SUPPORT 0x00000008
+#define KEXEC_DEBUG            0x00000010
  #define KEXEC_ARCH_MASK               0xffff0000

/*

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 9bb1f2b6b268..c7a869d32f87 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -42,6 +42,7 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned 
long entry,
        if (!image)
                return -ENOMEM;

+ kexec_core_dbg_print = !!(flags & KEXEC_DEBUG);

        image->start = entry;
        image->nr_segments = nr_segments;
        memcpy(image->segment, segments, nr_segments * sizeof(*segments));
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index fa00b239c5d9..865f2b14f23b 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -53,7 +53,7 @@ atomic_t __kexec_lock = ATOMIC_INIT(0);
  /* Flag to indicate we are going to kexec a new kernel */
  bool kexec_in_progress = false;

-bool kexec_file_dbg_print;

+bool kexec_core_dbg_print;

/*

   * When kexec transitions to the new kernel there is a one-to-one
@@ -576,6 +576,8 @@ void kimage_free(struct kimage *image)
        kimage_entry_t *ptr, entry;
        kimage_entry_t ind = 0;

+ kexec_core_dbg_print = false;

+
        if (!image)
                return;

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c

index eb62a9794242..4a24aadbad02 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -138,8 +138,6 @@ 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

@@ -314,7 +312,7 @@ kimage_file_alloc_init(struct kimage **rimage, int 
kernel_fd,
        if (!image)
                return -ENOMEM;

- kexec_file_dbg_print = !!(flags & KEXEC_FILE_DEBUG);

+       kexec_core_dbg_print = !!(flags & KEXEC_FILE_DEBUG);
        image->file_mode = 1;

#ifdef CONFIG_CRASH_DUMP

--
2.20.1