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

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Message-ID: <4FED52AA3D608E61+96b50af7-cc24-40b0-a723-3b01f8428831@uniontech.com>
Date: Fri, 24 Oct 2025 17:04:23 +0800
From: Qiang Ma <maqianga@...ontech.com>
To: Youling Tang <youling.tang@...ux.dev>, Huacai Chen <chenhuacai@...nel.org>
Cc: 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 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?


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
>>>
>