Re: [PATCH] kexec_file: remove unused arch_kexec_locate_mem_hole hook

[Mukesh Pilaniya]

Hi Sourabh,

On 29/08/26 10:28 am, Sourabh Jain wrote:
> Hello Mukesh,
> 
> On 28/08/26 18:50, Mukesh Pilaniya wrote:
>> Hi Sourabh,
>>
>> The patch touches three files across three subsystems so kexec: would be
>> a more accurate prefix than kexec_file, for e.g.:
>>
>> kexec: remove unused arch_kexec_locate_mem_hole hook
> 
> As I understand it, the kexec: prefix is generally used when the changes
> apply to both
> the kexec_load and kexec_file_load syscalls.
> 
> Since these changes are specific to kexec_file_load, I used the
> kexec_file: prefix for the patch title.
> 
> That said, I’m happy to follow the convention if you and others feel the
> patch should use the
> kexec: prefix. Otherwise, I would prefer to keep the kexec_file: prefix.
>

You're right, I hadn't noticed that the hook is entirely within the
CONFIG_KEXEC_FILE block and both callers are in the kexec_file_load
path. kexec_file: is the correct prefix here. Thanks for the clarification.

> 
>>
>> On 27/08/26 8:14 pm, Sourabh Jain wrote:
>>> No architecture provides an implementation of
>>> arch_kexec_locate_mem_hole(). Use kexec_locate_mem_hole() directly
>>> and remove the unused fallback wrapper from the kexec header.
>>>
>>> This simplifies the kexec memory allocation path without changing
>>> its behavior.
>>>
>> Also, it might be worth mentioning in the commit message that this hook
>> was originally introduced by commit f891f19736bd and that the last arch
>> override was removed in commit 6e5250eaa665; making it safe to remove
>> now.
> 
> Sure, I don’t mind including this in v2.
> 
> 
>>
>> Otherwise, the change looks good to me. Feel free to add:
>> Reviewed-by: Mukesh Pilaniya <mpilaniy@xxxxxxxxxx>
> 
> Thanks for the review.
> 
> - Sourabh Jain
> 
>>
>>> Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
>>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>>> Cc: Baoquan He <baoquan.he@xxxxxxxxx>
>>> Cc: Mike Rapoport <rppt@xxxxxxxxxx>
>>> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
>>> Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
>>> Cc: Paul Walmsley <pjw@xxxxxxxxxx>
>>> Cc: Pratyush Yadav <pratyush@xxxxxxxxxx>
>>> Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
>>> Cc: kexec@xxxxxxxxxxxxxxxxxxx
>>> Signed-off-by: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
>>> ---
>>>   arch/riscv/kernel/kexec_elf.c |  2 +-
>>>   include/linux/kexec.h         | 15 ---------------
>>>   kernel/kexec_file.c           |  2 +-
>>>   3 files changed, 2 insertions(+), 17 deletions(-)
>>>
>>> diff --git a/arch/riscv/kernel/kexec_elf.c b/arch/riscv/kernel/
>>> kexec_elf.c
>>> index 3e9a32acb8f2..ca5abbad59e5 100644
>>> --- a/arch/riscv/kernel/kexec_elf.c
>>> +++ b/arch/riscv/kernel/kexec_elf.c
>>> @@ -91,7 +91,7 @@ static int elf_find_pbase(struct kimage *image,
>>> unsigned long kernel_len,
>>>       kbuf.memsz = ALIGN(kernel_len, PAGE_SIZE);
>>>       kbuf.cma = NULL;
>>>       kbuf.top_down = false;
>>> -    ret = arch_kexec_locate_mem_hole(&kbuf);
>>> +    ret = kexec_locate_mem_hole(&kbuf);
>>>       if (!ret) {
>>>           *old_pbase = lowest_paddr;
>>>           *new_pbase = kbuf.mem;
>>> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
>>> index 0af8ae4fdd08..e5f1cfc11fef 100644
>>> --- a/include/linux/kexec.h
>>> +++ b/include/linux/kexec.h
>>> @@ -259,21 +259,6 @@ int kexec_kernel_verify_pe_sig(const char
>>> *kernel, unsigned long kernel_len);
>>>   extern int kexec_add_buffer(struct kexec_buf *kbuf);
>>>   int kexec_locate_mem_hole(struct kexec_buf *kbuf);
>>>   -#ifndef arch_kexec_locate_mem_hole
>>> -/**
>>> - * arch_kexec_locate_mem_hole - Find free memory to place the segments.
>>> - * @kbuf:                       Parameters for the memory search.
>>> - *
>>> - * On success, kbuf->mem will have the start address of the memory
>>> region found.
>>> - *
>>> - * Return: 0 on success, negative errno on error.
>>> - */
>>> -static inline int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
>>> -{
>>> -    return kexec_locate_mem_hole(kbuf);
>>> -}
>>> -#endif
>>> -
>>>   #ifndef arch_kexec_apply_relocations_add
>>>   /*
>>>    * arch_kexec_apply_relocations_add - apply relocations of type RELA
>>> diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
>>> index 59fb9d71e9d8..9a981359addd 100644
>>> --- a/kernel/kexec_file.c
>>> +++ b/kernel/kexec_file.c
>>> @@ -784,7 +784,7 @@ int kexec_add_buffer(struct kexec_buf *kbuf)
>>>       kbuf->cma = NULL;
>>>         /* Walk the RAM ranges and allocate a suitable range for the
>>> buffer */
>>> -    ret = arch_kexec_locate_mem_hole(kbuf);
>>> +    ret = kexec_locate_mem_hole(kbuf);
>>>       if (ret)
>>>           return ret;
>>>   
> 

-- 
Regards,
Mukesh Pilaniya