Re: [PATCH 2/3] mm: Pass vm_flags to generic_get_unmapped_area()

[Lorenzo Stoakes]

On Mon, Sep 02, 2024 at 08:08:14PM GMT, Mark Brown wrote:
> In preparation for using vm_flags to ensure guard pages for shadow stacks
> supply them as an argument to generic_get_unmapped_area(). The only user
> outside of the core code is the PowerPC book3s64 implementation which is
> trivially wrapping the generic implementation in the radix_enabled() case.
>
> Signed-off-by: Mark Brown <broo...@kernel.org>

Acked-by: Lorenzo Stoakes <lorenzo.stoa...@oracle.com> (for mm/mmap.c part)

> ---
>  arch/powerpc/mm/book3s64/slice.c |  4 ++--
>  include/linux/sched/mm.h         |  4 ++--
>  mm/mmap.c                        | 10 ++++++----
>  3 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s64/slice.c 
> b/arch/powerpc/mm/book3s64/slice.c
> index ada6bf896ef8..87307d0fc3b8 100644
> --- a/arch/powerpc/mm/book3s64/slice.c
> +++ b/arch/powerpc/mm/book3s64/slice.c
> @@ -641,7 +641,7 @@ unsigned long arch_get_unmapped_area(struct file *filp,
>                                    vm_flags_t vm_flags)
>  {
>       if (radix_enabled())
> -             return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
> +             return generic_get_unmapped_area(filp, addr, len, pgoff, flags, 
> vm_flags);
>
>       return slice_get_unmapped_area(addr, len, flags,
>                                      
> mm_ctx_user_psize(&current->mm->context), 0);
> @@ -655,7 +655,7 @@ unsigned long arch_get_unmapped_area_topdown(struct file 
> *filp,
>                                            vm_flags_t vm_flags)
>  {
>       if (radix_enabled())
> -             return generic_get_unmapped_area_topdown(filp, addr0, len, 
> pgoff, flags);
> +             return generic_get_unmapped_area_topdown(filp, addr0, len, 
> pgoff, flags, vm_flags);
>
>       return slice_get_unmapped_area(addr0, len, flags,
>                                      
> mm_ctx_user_psize(&current->mm->context), 1);
> diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
> index c4d34abc45d4..07bb8d4181d7 100644
> --- a/include/linux/sched/mm.h
> +++ b/include/linux/sched/mm.h
> @@ -204,11 +204,11 @@ unsigned long mm_get_unmapped_area_vmflags(struct 
> mm_struct *mm,
>  unsigned long
>  generic_get_unmapped_area(struct file *filp, unsigned long addr,
>                         unsigned long len, unsigned long pgoff,
> -                       unsigned long flags);
> +                       unsigned long flags, vm_flags_t vm_flags);
>  unsigned long
>  generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
>                                 unsigned long len, unsigned long pgoff,
> -                               unsigned long flags);
> +                               unsigned long flags, vm_flags_t vm_flags);
>  #else
>  static inline void arch_pick_mmap_layout(struct mm_struct *mm,
>                                        struct rlimit *rlim_stack) {}
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 7528146f886f..b06ba847c96e 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1789,7 +1789,7 @@ unsigned long vm_unmapped_area(struct 
> vm_unmapped_area_info *info)
>  unsigned long
>  generic_get_unmapped_area(struct file *filp, unsigned long addr,
>                         unsigned long len, unsigned long pgoff,
> -                       unsigned long flags)
> +                       unsigned long flags, vm_flags_t vm_flags)
>  {
>       struct mm_struct *mm = current->mm;
>       struct vm_area_struct *vma, *prev;
> @@ -1823,7 +1823,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long 
> addr,
>                      unsigned long len, unsigned long pgoff,
>                      unsigned long flags, vm_flags_t vm_flags)
>  {
> -     return generic_get_unmapped_area(filp, addr, len, pgoff, flags);
> +     return generic_get_unmapped_area(filp, addr, len, pgoff, flags,
> +                                      vm_flags);
>  }
>  #endif
>
> @@ -1834,7 +1835,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long 
> addr,
>  unsigned long
>  generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
>                                 unsigned long len, unsigned long pgoff,
> -                               unsigned long flags)
> +                               unsigned long flags, vm_flags_t vm_flags)
>  {
>       struct vm_area_struct *vma, *prev;
>       struct mm_struct *mm = current->mm;
> @@ -1887,7 +1888,8 @@ arch_get_unmapped_area_topdown(struct file *filp, 
> unsigned long addr,
>                              unsigned long len, unsigned long pgoff,
>                              unsigned long flags, vm_flags_t vm_flags)
>  {
> -     return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);
> +     return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags,
> +                                              vm_flags);
>  }
>  #endif
>
>
> --
> 2.39.2
>