Subject: Re: [PATCH] powerpc/mm: export symbols for lazy_mmu_mode KUnit tests

From: Ritesh Harjani (IBM) <[email-masked]>
Date: Wed, 17 Dec 2025 22:15:16 +0530

Kevin Brodsky <[email-masked]> writes:

> Upcoming KUnit tests will call lazy_mmu_mode_{enable,disable}.
> These tests may be built as a module, and because of inlining this
> means that symbols referenced by arch_{enter,leave}_lazy_mmu_mode
> need to be exported.
>
> Suggested-by: Ryan Roberts <[email-masked]>
> Suggested-by: Ritesh Harjani (IBM) <[email-masked]>
> Signed-off-by: Kevin Brodsky <[email-masked]>
> ---

Hi Kevin, 

I guess, this can give following errors:

../arch/powerpc/mm/book3s64/hash_tlb.c:33:1: error: data definition has no type or storage class [-Werror]
   33 | EXPORT_SYMBOL_IF_KUNIT(ppc64_tlb_batch); /* For lazy_mmu_mode KUnit tests */
      | ^~~~~~~~~~~~~~~~~~~~~~
../arch/powerpc/mm/book3s64/hash_tlb.c:33:1: error: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL_IF_KUNIT’ [-Werror=implicit-int]
../arch/powerpc/mm/book3s64/hash_tlb.c:33:1: error: parameter names (without types) in function declaration [-Werror]
../arch/powerpc/mm/book3s64/hash_tlb.c:158:1: error: data definition has no type or storage class [-Werror]
  158 | EXPORT_SYMBOL_IF_KUNIT(__flush_tlb_pending); /* For lazy_mmu_mode KUnit tests */
      | ^~~~~~~~~~~~~~~~~~~~~~
../arch/powerpc/mm/book3s64/hash_tlb.c:158:1: error: type defaults to ‘int’ in declaration of ‘EXPORT_SYMBOL_IF_KUNIT’ [-Werror=implicit-int]
../arch/powerpc/mm/book3s64/hash_tlb.c:158:1: error: parameter names (without types) in function declaration [-Werror]
  AR      init/built-in.a
cc1: all warnings being treated as errors
make[6]: *** [../scripts/Makefile.build:287: arch/powerpc/mm/book3s64/hash_tlb.o] Error 1
make[5]: *** [../scripts/Makefile.build:556: arch/powerpc/mm/book3s64] Error 2

IMO, we will need the following header in hash_tlb.c

+#include <kunit/visibility.h>

-ritesh

>
> Andrew, please add this patch just before the last patch in the series
> ("mm: Add basic tests for lazy_mmu"). Thanks!
> ---
>  arch/powerpc/mm/book3s64/hash_tlb.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c
> index fbdeb8981ae7..9e622519a423 100644
> --- a/arch/powerpc/mm/book3s64/hash_tlb.c
> +++ b/arch/powerpc/mm/book3s64/hash_tlb.c
> @@ -30,6 +30,7 @@
>  #include <trace/events/thp.h>
>  
>  DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch);
> +EXPORT_SYMBOL_IF_KUNIT(ppc64_tlb_batch); /* For lazy_mmu_mode KUnit tests */
>  
>  /*
>   * A linux PTE was changed and the corresponding hash table entry
> @@ -154,6 +155,7 @@ void __flush_tlb_pending(struct ppc64_tlb_batch *batch)
>  		flush_hash_range(i, local);
>  	batch->index = 0;
>  }
> +EXPORT_SYMBOL_IF_KUNIT(__flush_tlb_pending); /* For lazy_mmu_mode KUnit tests */
>  
>  void hash__tlb_flush(struct mmu_gather *tlb)
>  {
>
> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
> -- 
> 2.51.2