On Tue, Feb 28, 2023 at 09:37:05PM +0000, Matthew Wilcox (Oracle) wrote:
> flush_icache_page() is deprecated but not yet removed, so add
> a range version of it. Change the documentation to refer to
> update_mmu_cache_range() instead of update_mmu_cache().
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> ---
> Documentation/core-api/cachetlb.rst | 35 +++++++++++++++--------------
> include/asm-generic/cacheflush.h | 5 +++++
> 2 files changed, 23 insertions(+), 17 deletions(-)
>
> diff --git a/Documentation/core-api/cachetlb.rst b/Documentation/core-api/cachetlb.rst
> index 5c0552e78c58..d4c9e2a28d36 100644
> --- a/Documentation/core-api/cachetlb.rst
> +++ b/Documentation/core-api/cachetlb.rst
> @@ -88,13 +88,13 @@ changes occur:
>
> This is used primarily during fault processing.
>
> -5) ``void update_mmu_cache(struct vm_area_struct *vma,
> - unsigned long address, pte_t *ptep)``
> +5) ``void update_mmu_cache_range(struct vm_area_struct *vma,
> + unsigned long address, pte_t *ptep, unsigned int nr)``
>
> - At the end of every page fault, this routine is invoked to
> - tell the architecture specific code that a translation
> - now exists at virtual address "address" for address space
> - "vma->vm_mm", in the software page tables.
> + At the end of every page fault, this routine is invoked to tell
> + the architecture specific code that translations now exists
> + in the software page tables for address space "vma->vm_mm"
> + at virtual address "address" for "nr" consecutive pages.
>
> A port may use this information in any way it so chooses.
> For example, it could use this event to pre-load TLB
> @@ -306,17 +306,18 @@ maps this page at its virtual address.
> private". The kernel guarantees that, for pagecache pages, it will
> clear this bit when such a page first enters the pagecache.
>
> - This allows these interfaces to be implemented much more efficiently.
> - It allows one to "defer" (perhaps indefinitely) the actual flush if
> - there are currently no user processes mapping this page. See sparc64's
> - flush_dcache_page and update_mmu_cache implementations for an example
> - of how to go about doing this.
> + This allows these interfaces to be implemented much more
> + efficiently. It allows one to "defer" (perhaps indefinitely) the
> + actual flush if there are currently no user processes mapping this
> + page. See sparc64's flush_dcache_page and update_mmu_cache_range
> + implementations for an example of how to go about doing this.
>
> - The idea is, first at flush_dcache_page() time, if page_file_mapping()
> - returns a mapping, and mapping_mapped on that mapping returns %false,
> - just mark the architecture private page flag bit. Later, in
> - update_mmu_cache(), a check is made of this flag bit, and if set the
> - flush is done and the flag bit is cleared.
> + The idea is, first at flush_dcache_page() time, if
> + page_file_mapping() returns a mapping, and mapping_mapped on that
> + mapping returns %false, just mark the architecture private page
> + flag bit. Later, in update_mmu_cache_range(), a check is made
> + of this flag bit, and if set the flush is done and the flag bit
> + is cleared.
>
> .. important::
>
> @@ -369,7 +370,7 @@ maps this page at its virtual address.
> ``void flush_icache_page(struct vm_area_struct *vma, struct page *page)``
>
> All the functionality of flush_icache_page can be implemented in
> - flush_dcache_page and update_mmu_cache. In the future, the hope
> + flush_dcache_page and update_mmu_cache_range. In the future, the hope
> is to remove this interface completely.
>
> The final category of APIs is for I/O to deliberately aliased address
> diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cacheflush.h
> index f46258d1a080..09d51a680765 100644
> --- a/include/asm-generic/cacheflush.h
> +++ b/include/asm-generic/cacheflush.h
> @@ -78,6 +78,11 @@ static inline void flush_icache_range(unsigned long start, unsigned long end)
> #endif
>
> #ifndef flush_icache_page
> +static inline void flush_icache_pages(struct vm_area_struct *vma,
> + struct page *page, unsigned int nr)
> +{
> +}
> +
> static inline void flush_icache_page(struct vm_area_struct *vma,
> struct page *page)
> {
> --
> 2.39.1
>
>
--
Sincerely yours,
Mike.
