On Sat, Mar 4, 2023 at 10:51 PM Jiaqi Yan <jiaqiyan@xxxxxxxxxx> wrote:
>
> Similar to how copy_mc_user_highpage is implemented for
> copy_user_highpage on #MC supported architecture, introduce
> the #MC handled version of copy_highpage.
>
> This helper has immediate usage when khugepaged wants to copy
> file-backed memory pages and tolerate #MC.
>
> Signed-off-by: Jiaqi Yan <jiaqiyan@xxxxxxxxxx>
> ---
> include/linux/highmem.h | 54 +++++++++++++++++++++++++++++++----------
> 1 file changed, 41 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/highmem.h b/include/linux/highmem.h
> index 1128b7114931f..7cbecae39b3eb 100644
> --- a/include/linux/highmem.h
> +++ b/include/linux/highmem.h
> @@ -315,7 +315,29 @@ static inline void copy_user_highpage(struct page *to, struct page *from,
>
> #endif
>
> +#ifndef __HAVE_ARCH_COPY_HIGHPAGE
> +
> +static inline void copy_highpage(struct page *to, struct page *from)
> +{
> + char *vfrom, *vto;
> +
> + vfrom = kmap_local_page(from);
> + vto = kmap_local_page(to);
> + copy_page(vto, vfrom);
> + kmsan_copy_page_meta(to, from);
> + kunmap_local(vto);
> + kunmap_local(vfrom);
> +}
> +
> +#endif
> +
> #ifdef copy_mc_to_kernel
> +/*
> + * If architecture supports machine check exception handling, define the
> + * #MC versions of copy_user_highpage and copy_highpage. They copy a memory
> + * page with #MC in source page (@from) handled, and return the number
> + * of bytes not copied if there was a #MC, otherwise 0 for success.
> + */
I know that back in v8, Andrew said copy_mc_* should not be inline,
but I am still putting them here as inline functions because to me
they blend in this file well. However, if you have strong opinions,
let me know and I will move copy_mc_user_highpage + copy_mc_highpage
to a .c file (maybe highmem.c?).
> static inline int copy_mc_user_highpage(struct page *to, struct page *from,
> unsigned long vaddr, struct vm_area_struct *vma)
> {
> @@ -332,29 +354,35 @@ static inline int copy_mc_user_highpage(struct page *to, struct page *from,
>
> return ret;
> }
> -#else
> -static inline int copy_mc_user_highpage(struct page *to, struct page *from,
> - unsigned long vaddr, struct vm_area_struct *vma)
> -{
> - copy_user_highpage(to, from, vaddr, vma);
> - return 0;
> -}
> -#endif
>
> -#ifndef __HAVE_ARCH_COPY_HIGHPAGE
> -
> -static inline void copy_highpage(struct page *to, struct page *from)
> +static inline int copy_mc_highpage(struct page *to, struct page *from)
> {
> + unsigned long ret;
> char *vfrom, *vto;
>
> vfrom = kmap_local_page(from);
> vto = kmap_local_page(to);
> - copy_page(vto, vfrom);
> - kmsan_copy_page_meta(to, from);
> + ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE);
> + if (!ret)
> + kmsan_copy_page_meta(to, from);
> kunmap_local(vto);
> kunmap_local(vfrom);
> +
> + return ret;
> +}
> +#else
> +static inline int copy_mc_user_highpage(struct page *to, struct page *from,
> + unsigned long vaddr, struct vm_area_struct *vma)
> +{
> + copy_user_highpage(to, from, vaddr, vma);
> + return 0;
> }
>
> +static inline int copy_mc_highpage(struct page *to, struct page *from)
> +{
> + copy_highpage(to, from);
> + return 0;
> +}
> #endif
>
> static inline void memcpy_page(struct page *dst_page, size_t dst_off,
> --
> 2.40.0.rc0.216.gc4246ad0f0-goog
>
