[PATCH v2 0/4] kexec: print out debugging message if required for kexec_load

[Qiang Ma]

Overview:
=========
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.
    
Next, we need to do some things in this patchset:
    
1. rename kexec_file_dbg_print to kexec_core_dbg_print
2. Add KEXEC_DEBUG
3. Initialize kexec_core_dbg_print for kexec
4. Fix uninitialized struct kimage *image pointer 
5. Set the reset of kexec_file_dbg_print to kimage_free

Testing:
=========
I did testing on x86_64, arm64 and loongarch. On x86_64, the printed messages
look like below:

unset CONFIG_KEXEC_FILE:
[   81.476959] kexec: nr_segments = 7
[   81.477565] kexec: segment[0]: buf=0x00000000c22469d2 bufsz=0x70 mem=0x100000 memsz=0x1000
[   81.478797] kexec: segment[1]: buf=0x00000000dedbb3b1 bufsz=0x140 mem=0x101000 memsz=0x1000
[   81.480075] kexec: segment[2]: buf=0x00000000d7657a33 bufsz=0x30 mem=0x102000 memsz=0x1000
[   81.481288] kexec: segment[3]: buf=0x00000000c7eb60a6 bufsz=0x16f40a8 mem=0x23bd0b000 memsz=0x16f5000
[   81.489018] kexec: segment[4]: buf=0x00000000d1ca53c8 bufsz=0xd73400 mem=0x23d400000 memsz=0x2ab7000
[   81.499697] kexec: segment[5]: buf=0x00000000697bac5a bufsz=0x50dc mem=0x23fff1000 memsz=0x6000
[   81.501084] kexec: segment[6]: buf=0x000000001f743a68 bufsz=0x70e0 mem=0x23fff7000 memsz=0x9000
[   81.502374] kexec: kexec_load: type:0, start:0x23fff7700 head:0x10a4b9002 flags:0x3e0010

set CONFIG_KEXEC_FILE
[   36.774228] kexec_file: kernel: 0000000066c386c8 kernel_size: 0xd78400
[   36.821814] kexec-bzImage64: Loaded purgatory at 0x23fffb000
[   36.821826] kexec-bzImage64: Loaded boot_param, command line and misc at 0x23fff9000 bufsz=0x12d0 memsz=0x2000
[   36.821829] kexec-bzImage64: Loaded 64bit kernel at 0x23d400000 bufsz=0xd73400 memsz=0x2ab7000
[   36.821918] kexec-bzImage64: Loaded initrd at 0x23bd0b000 bufsz=0x16f40a8 memsz=0x16f40a8
[   36.821920] kexec-bzImage64: Final command line is: root=/dev/mapper/test-root crashkernel=auto rd.lvm.lv=test/root
[   36.821925] kexec-bzImage64: E820 memmap:
[   36.821926] kexec-bzImage64: 0000000000000000-000000000009ffff (1)
[   36.821928] kexec-bzImage64: 0000000000100000-0000000000811fff (1)
[   36.821930] kexec-bzImage64: 0000000000812000-0000000000812fff (2)
[   36.821931] kexec-bzImage64: 0000000000813000-00000000bee38fff (1)
[   36.821933] kexec-bzImage64: 00000000bee39000-00000000beec2fff (2)
[   36.821934] kexec-bzImage64: 00000000beec3000-00000000bf8ecfff (1)
[   36.821935] kexec-bzImage64: 00000000bf8ed000-00000000bfb6cfff (2)
[   36.821936] kexec-bzImage64: 00000000bfb6d000-00000000bfb7efff (3)
[   36.821937] kexec-bzImage64: 00000000bfb7f000-00000000bfbfefff (4)
[   36.821938] kexec-bzImage64: 00000000bfbff000-00000000bff7bfff (1)
[   36.821939] kexec-bzImage64: 00000000bff7c000-00000000bfffffff (2)
[   36.821940] kexec-bzImage64: 00000000feffc000-00000000feffffff (2)
[   36.821941] kexec-bzImage64: 00000000ffc00000-00000000ffffffff (2)
[   36.821942] kexec-bzImage64: 0000000100000000-000000023fffffff (1)
[   36.872348] kexec_file: nr_segments = 4
[   36.872356] kexec_file: segment[0]: buf=0x000000005314ece7 bufsz=0x4000 mem=0x23fffb000 memsz=0x5000
[   36.872370] kexec_file: segment[1]: buf=0x000000006e59b143 bufsz=0x12d0 mem=0x23fff9000 memsz=0x2000
[   36.872374] kexec_file: segment[2]: buf=0x00000000eb7b1fc3 bufsz=0xd73400 mem=0x23d400000 memsz=0x2ab7000
[   36.882172] kexec_file: segment[3]: buf=0x000000006af76441 bufsz=0x16f40a8 mem=0x23bd0b000 memsz=0x16f5000
[   36.889113] kexec_file: kexec_file_load: type:0, start:0x23fffb150 head:0x101a2e002 flags:0x8

Changes in v2:
==========
- Unify the debug flag of kexec and kexec_file
- Fix uninitialized struct kimage *image pointer
- Fix the issue of mismatch between loop variable types

Qiang Ma (4):
  kexec: Fix uninitialized struct kimage *image pointer
  kexec: add kexec_core flag to control debug printing
  kexec: print out debugging message if required for kexec_load
  kexec_file: Fix the issue of mismatch between loop variable types

 include/linux/kexec.h      |  9 +++++----
 include/uapi/linux/kexec.h |  1 +
 kernel/kexec.c             | 16 +++++++++++++++-
 kernel/kexec_core.c        |  4 +++-
 kernel/kexec_file.c        |  9 ++++-----
 5 files changed, 28 insertions(+), 11 deletions(-)

-- 
2.20.1