linux-kernel - Re: [PATCH] LoongArch: kexec_file: print out debugging message if required

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Message-ID: <1b865cb8-5262-432f-a090-c0bd9064dae2@linux.dev>
Date: Fri, 24 Oct 2025 17:27:57 +0800
From: Youling Tang <youling.tang@...ux.dev>
To: Qiang Ma <maqianga@...ontech.com>
Cc: Huacai Chen <chenhuacai@...nel.org>, kernel@...0n.name,
 loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] LoongArch: kexec_file: print out debugging message if
 required


On 10/24/25 17:04, Qiang Ma wrote:
>
> 在 2025/10/24 15:26, Youling Tang 写道:
>> On 10/24/25 15:04, Huacai Chen wrote:
>>
>>> Hi, Youling,
>>>
>>> What do you think about this?
>>>
>>> Huacai
>>>
>>> On Tue, Oct 21, 2025 at 5:12 PM Qiang Ma <maqianga@...ontech.com> 
>>> wrote:
>>>> When specifying '-d' for kexec_file_load interface, loaded locations
>>>> of kernel/initrd/cmdline etc can be printed out to help debug.
>>
>> Although kexec_image_info() could be considered for removal in the 
>> case of kexec_file,
>> in the context of kexec_load, when using the -d parameter of 
>> kexec-tools, although the
>> userspace program outputs extensive debugging information, it is 
>> recommended to retain
>> this information during the debugging phase to verify the accuracy of 
>> data transmission
>> after it is passed into the kernel.
>>
> In the system call kexec_file_load(), after machine_kexec_prepare() is 
> executed,
>
> there will be the same print information as the kexec_image_info(), 
> and no modifications
>
> were made to the printed information during this period. Therefore, it 
> can also verify
>
> the accuracy of the data, right?


If only for kexec_file_load, we can directly remove kexec_image_info().
But for kexec_load, I suggest keeping it.

Youling.
>
>
> Thanks,
>
> Qiang.
>
>
>> Thanks,
>> Youling.
>>>>
>>>> Commit eb7622d908a0 ("kexec_file, riscv: print out debugging message
>>>> if required") fixes the same issue on RISC-V.
>>>>
>>>> So, remove kexec_image_info() because the content has been printed
>>>> out in generic code.
>>>>
>>>> And on Loongson-3A5000, the printed messages look like below:
>>>>
>>>> [  288.667939] kexec_file: kernel: 00000000d9aad283 kernel_size: 
>>>> 0x2e77f30
>>>> [  288.668414] kexec_file(EFI): No LoongArch PE image header.
>>>> [  288.703104] kexec_file: Loaded initrd at 0x80000000 
>>>> bufsz=0x1637cd0 memsz=0x1638000
>>>> [  288.703674] kexec_file(ELF): Loaded kernel at 0x9c20000 
>>>> bufsz=0x27f1800 memsz=0x2950000
>>>> [  288.704092] kexec_file: nr_segments = 2
>>>> [  288.704277] kexec_file: segment[0]: buf=0x00000000cc3e6c33 
>>>> bufsz=0x27f1800 mem=0x9c20000 memsz=0x2950000
>>>> [  288.741213] kexec_file: segment[1]: buf=0x00000000bb75a541 
>>>> bufsz=0x1637cd0 mem=0x80000000 memsz=0x1638000
>>>> [  288.757182] kexec_file: kexec_file_load: type:0, start:0xb15d000 
>>>> head:0x18db60002 flags:0x8
>>>>
>>>> Signed-off-by: Qiang Ma <maqianga@...ontech.com>
>>>> ---
>>>>   arch/loongarch/kernel/machine_kexec.c | 22 ----------------------
>>>>   1 file changed, 22 deletions(-)
>>>>
>>>> diff --git a/arch/loongarch/kernel/machine_kexec.c 
>>>> b/arch/loongarch/kernel/machine_kexec.c
>>>> index e4b2bbc47e62..2d64b7c81e5e 100644
>>>> --- a/arch/loongarch/kernel/machine_kexec.c
>>>> +++ b/arch/loongarch/kernel/machine_kexec.c
>>>> @@ -39,34 +39,12 @@ static unsigned long systable_ptr;
>>>>   static unsigned long start_addr;
>>>>   static unsigned long first_ind_entry;
>>>>
>>>> -static void kexec_image_info(const struct kimage *kimage)
>>>> -{
>>>> -       unsigned long i;
>>>> -
>>>> -       pr_debug("kexec kimage info:\n");
>>>> -       pr_debug("\ttype:        %d\n", kimage->type);
>>>> -       pr_debug("\tstart:       %lx\n", kimage->start);
>>>> -       pr_debug("\thead:        %lx\n", kimage->head);
>>>> -       pr_debug("\tnr_segments: %lu\n", kimage->nr_segments);
>>>> -
>>>> -       for (i = 0; i < kimage->nr_segments; i++) {
>>>> -               pr_debug("\t    segment[%lu]: %016lx - %016lx", i,
>>>> -                       kimage->segment[i].mem,
>>>> -                       kimage->segment[i].mem + 
>>>> kimage->segment[i].memsz);
>>>> -               pr_debug("\t\t0x%lx bytes, %lu pages\n",
>>>> -                       (unsigned long)kimage->segment[i].memsz,
>>>> -                       (unsigned long)kimage->segment[i].memsz /  
>>>> PAGE_SIZE);
>>>> -       }
>>>> -}
>>>> -
>>>>   int machine_kexec_prepare(struct kimage *kimage)
>>>>   {
>>>>          int i;
>>>>          char *bootloader = "kexec";
>>>>          void *cmdline_ptr = (void *)KEXEC_CMDLINE_ADDR;
>>>>
>>>> -       kexec_image_info(kimage);
>>>> -
>>>>          kimage->arch.efi_boot = fw_arg0;
>>>>          kimage->arch.systable_ptr = fw_arg2;
>>>>
>>>> -- 
>>>> 2.20.1
>>>>
>>
>