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

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Message-ID: <4BEEB4B9B4B77DC9+01857891-fef2-4160-8981-939adb46368a@uniontech.com>
Date: Fri, 24 Oct 2025 21:01:44 +0800
From: Qiang Ma <maqianga@...ontech.com>
To: Youling Tang <youling.tang@...ux.dev>
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


在 2025/10/24 17:27, Youling Tang 写道:
>
> 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.

I see.

But I think it's not necessary to add this print information to both

kexec_load and kexec_file_load. Just keep one.


Qiang.


>
> 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
>>>>>
>>>
>>
>