[PATCH] [v2] arm64: hugetlbpage: avoid unused-but-set-parameter warning (gcc-16)

[PATCH] [v2] arm64: hugetlbpage: avoid unused-but-set-parameter warning (gcc-16)

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

gcc-16 warns about an instance that older compilers did not:

arch/arm64/mm/hugetlbpage.c: In function 'huge_pte_clear':
arch/arm64/mm/hugetlbpage.c:369:57: error: parameter 'addr' set but not used [-Werror=unused-but-set-parameter=]

The issue here is that __pte_clear() does not actually use its second
argument when CONFIG_ARM64_CONTPTE is disabled.

Replace the macro with an inline function to let the compiler see
how the argument is used.

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: replace my original patch with Catalin's suggestion
---
 arch/arm64/include/asm/pgtable.h | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index a17eb8a76788..b3e58735c49b 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -144,8 +144,6 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
 	__pte(__phys_to_pte_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
 
 #define pte_none(pte)		(!pte_val(pte))
-#define __pte_clear(mm, addr, ptep) \
-				__set_pte(ptep, __pte(0))
 #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
 
 /*
@@ -1284,6 +1282,13 @@ static inline bool pud_user_accessible_page(pud_t pud, unsigned long addr)
 /*
  * Atomic pte/pmd modifications.
  */
+
+static inline void __pte_clear(struct mm_struct *mm,
+			       unsigned long addr, pte_t *ptep)
+{
+	__set_pte(ptep, __pte(0));
+}
+
 static inline int __ptep_test_and_clear_young(struct vm_area_struct *vma,
 					      unsigned long address,
 					      pte_t *ptep)
-- 
2.39.5

Re: [PATCH] [v2] arm64: hugetlbpage: avoid unused-but-set-parameter warning (gcc-16)

[Dev Jain]

On 13/02/26 9:52 pm, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> gcc-16 warns about an instance that older compilers did not:
>
> arch/arm64/mm/hugetlbpage.c: In function 'huge_pte_clear':
> arch/arm64/mm/hugetlbpage.c:369:57: error: parameter 'addr' set but not used [-Werror=unused-but-set-parameter=]
>
> The issue here is that __pte_clear() does not actually use its second
> argument when CONFIG_ARM64_CONTPTE is disabled.

But that is true even when the config is on? __pte_clear has an unconditional definition.

>
> Replace the macro with an inline function to let the compiler see
> how the argument is used.
>
> Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> v2: replace my original patch with Catalin's suggestion
> ---
>  arch/arm64/include/asm/pgtable.h | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index a17eb8a76788..b3e58735c49b 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -144,8 +144,6 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
>  	__pte(__phys_to_pte_val((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
>  
>  #define pte_none(pte)		(!pte_val(pte))
> -#define __pte_clear(mm, addr, ptep) \
> -				__set_pte(ptep, __pte(0))
>  #define pte_page(pte)		(pfn_to_page(pte_pfn(pte)))
>  
>  /*
> @@ -1284,6 +1282,13 @@ static inline bool pud_user_accessible_page(pud_t pud, unsigned long addr)
>  /*
>   * Atomic pte/pmd modifications.
>   */
> +
> +static inline void __pte_clear(struct mm_struct *mm,
> +			       unsigned long addr, pte_t *ptep)
> +{
> +	__set_pte(ptep, __pte(0));
> +}
> +
>  static inline int __ptep_test_and_clear_young(struct vm_area_struct *vma,
>  					      unsigned long address,
>  					      pte_t *ptep)

Re: [PATCH] [v2] arm64: hugetlbpage: avoid unused-but-set-parameter warning (gcc-16)

[Arnd Bergmann]

On Mon, Feb 16, 2026, at 07:31, Dev Jain wrote:
> On 13/02/26 9:52 pm, Arnd Bergmann wrote:

>>
>> The issue here is that __pte_clear() does not actually use its second
>> argument when CONFIG_ARM64_CONTPTE is disabled.
>
> But that is true even when the config is on? __pte_clear has an 
> unconditional definition.
>

No, you're right. I'll rephrase the changelog and send a v3.

When CONFIG_ARM64_CONTPTE is disabled, the warning doesn't
appear because the argument is unused by never changed as the
loop collapses into a single call.

     Arnd