Re: [PATCH v8 01/10] arm64/mm: add pte_set_huge() and pte_clear_huge()

[Barry Song]

On Thu, Sep 17, 2026 at 1:29 PM Wen Jiang <jiangwenxiaomi@xxxxxxxxx> wrote:
>
> From: Wen Jiang <jiangwen6@xxxxxxxxxx>
>
> vmap installs PTE-level block mappings (PTE_CONT on arm64) by reusing
> set_huge_pte_at() and huge_ptep_get_and_clear(), which are HugeTLB
> helpers gated by CONFIG_HUGETLB_PAGE. This makes the feature silently
> unavailable on CONFIG_HUGETLB_PAGE=n kernels and couples mm/vmalloc.c to
> HugeTLB internals it does not otherwise need.
>
> Add pte_set_huge()/pte_clear_huge() to arm64, joining the existing
> pmd_set_huge()/pud_set_huge() family in mm/mmu.c. They build on
> __set_ptes() and __get_and_clear_full_ptes() directly, so they do not
> depend on CONFIG_HUGETLB_PAGE.
>
> There is no caller yet: mm/vmalloc.c is converted later in this series,
> once the generic fallbacks are in place.
>
> Signed-off-by: Wen Jiang <jiangwen6@xxxxxxxxxx>

I tried to apply the patch to mm-new, but it doesn't apply.

% git am raw
Applying: arm64/mm: add pte_set_huge() and pte_clear_huge()
error: patch failed: arch/arm64/mm/mmu.c:1872
error: arch/arm64/mm/mmu.c: patch does not apply
Patch failed at 0001 arm64/mm: add pte_set_huge() and pte_clear_huge()
hint: Use 'git am --show-current-patch=diff' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

% patch -p1 < raw
patching file 'arch/arm64/include/asm/pgtable.h'
patching file 'arch/arm64/mm/mmu.c'
1 out of 1 hunks failed--saving rejects to 'arch/arm64/mm/mmu.c.rej'


[...]

> +void pte_set_huge(pte_t *ptep, unsigned long addr, phys_addr_t phys,
> +                 pgprot_t prot, unsigned long size)
> +{
> +       unsigned long pfn = __phys_to_pfn(phys);
> +       pte_t new_pte = pte_mkcont(pfn_pte(pfn, prot));

Maybe we can drop the `new_` prefix.

> +       unsigned int nr = size >> PAGE_SHIFT;
> +
> +       VM_WARN_ON(!IS_ALIGNED(pfn, CONT_PTES));
> +       VM_WARN_ON(!IS_ALIGNED(size, CONT_PTE_SIZE));

Do we also need to check that `addr` is aligned?

Best Regards
Barry