Re: [PATCH v8 4/6] powerpc/tlb: Add local flush for page given mm_struct and psize

[Russell Currey <ruscur@russell.cc>]

On Fri, 2022-10-21 at 16:22 +1100, Benjamin Gray wrote:
> Adds a local TLB flush operation that works given an mm_struct, VA to
> flush, and page size representation.
> 
> This removes the need to create a vm_area_struct, which the temporary
> patching mm work does not need.
> 
> Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/32/tlbflush.h      | 9 +++++++++
>  arch/powerpc/include/asm/book3s/64/tlbflush-hash.h | 5 +++++
>  arch/powerpc/include/asm/book3s/64/tlbflush.h      | 8 ++++++++
>  arch/powerpc/include/asm/nohash/tlbflush.h         | 1 +
>  4 files changed, 23 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/book3s/32/tlbflush.h
> b/arch/powerpc/include/asm/book3s/32/tlbflush.h
> index ba1743c52b56..e5a688cebf69 100644
> --- a/arch/powerpc/include/asm/book3s/32/tlbflush.h
> +++ b/arch/powerpc/include/asm/book3s/32/tlbflush.h
> @@ -2,6 +2,8 @@
>  #ifndef _ASM_POWERPC_BOOK3S_32_TLBFLUSH_H
>  #define _ASM_POWERPC_BOOK3S_32_TLBFLUSH_H
>  
> +#include <linux/build_bug.h>
> +
>  #define MMU_NO_CONTEXT      (0)
>  /*
>   * TLB flushing for "classic" hash-MMU 32-bit CPUs, 6xx, 7xx, 7xxx
> @@ -74,6 +76,13 @@ static inline void local_flush_tlb_page(struct
> vm_area_struct *vma,
>  {
>         flush_tlb_page(vma, vmaddr);
>  }
> +
> +static inline void local_flush_tlb_page_psize(struct mm_struct *mm,
> unsigned long vmaddr, int psize)
> +{
> +       BUILD_BUG_ON(psize != MMU_PAGE_4K);
> +       flush_range(mm, vmaddr, vmaddr + PAGE_SIZE);
> +}
> +
>  static inline void local_flush_tlb_mm(struct mm_struct *mm)
>  {
>         flush_tlb_mm(mm);
> diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
> b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
> index fab8332fe1ad..8fd9dc49b2a1 100644
> --- a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
> +++ b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
> @@ -94,6 +94,11 @@ static inline void
> hash__local_flush_tlb_page(struct vm_area_struct *vma,
>  {
>  }
>  
> +static inline void hash__local_flush_tlb_page_psize(struct mm_struct
> *mm,
> +                                                   unsigned long
> vmaddr, int psize)
> +{
> +}
> +
>  static inline void hash__flush_tlb_page(struct vm_area_struct *vma,
>                                     unsigned long vmaddr)
>  {
> diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush.h
> b/arch/powerpc/include/asm/book3s/64/tlbflush.h
> index 67655cd60545..2d839dd5c08c 100644
> --- a/arch/powerpc/include/asm/book3s/64/tlbflush.h
> +++ b/arch/powerpc/include/asm/book3s/64/tlbflush.h
> @@ -92,6 +92,14 @@ static inline void local_flush_tlb_page(struct
> vm_area_struct *vma,
>         return hash__local_flush_tlb_page(vma, vmaddr);
>  }
>  
> +static inline void local_flush_tlb_page_psize(struct mm_struct *mm,
> +                                             unsigned long vmaddr,
> int psize)
> +{
> +       if (radix_enabled())
> +               return radix__local_flush_tlb_page_psize(mm, vmaddr,
> psize);
> +       return hash__local_flush_tlb_page_psize(mm, vmaddr, psize);
> +}
> +
>  static inline void local_flush_all_mm(struct mm_struct *mm)
>  {
>         if (radix_enabled())
> diff --git a/arch/powerpc/include/asm/nohash/tlbflush.h
> b/arch/powerpc/include/asm/nohash/tlbflush.h
> index bdaf34ad41ea..59bce0ebdcf4 100644
> --- a/arch/powerpc/include/asm/nohash/tlbflush.h
> +++ b/arch/powerpc/include/asm/nohash/tlbflush.h
> @@ -58,6 +58,7 @@ static inline void flush_tlb_kernel_range(unsigned
> long start, unsigned long end
>  extern void flush_tlb_kernel_range(unsigned long start, unsigned
> long end);
>  extern void local_flush_tlb_mm(struct mm_struct *mm);
>  extern void local_flush_tlb_page(struct vm_area_struct *vma,
> unsigned long vmaddr);
> +extern void local_flush_tlb_page_psize(struct mm_struct *mm,
> unsigned long vmaddr, int psize);

This misses a definition for PPC_8xx which leads to a build failure as
found by snowpatch here:
https://github.com/ruscur/linux-ci/actions/runs/3295033018/jobs/5433162658#step:4:116

>  
>  extern void __local_flush_tlb_page(struct mm_struct *mm, unsigned
> long vmaddr,
>                                    int tsize, int ind);