On Fri, Feb 04, 2022 at 08:27:37AM +0530, Anshuman Khandual wrote:
>
> On 2/3/22 11:45 PM, Mike Rapoport wrote:
> > On Mon, Jan 24, 2022 at 06:26:41PM +0530, Anshuman Khandual wrote:
> >> This defines and exports a platform specific custom vm_get_page_prot() via
> >> subscribing ARCH_HAS_VM_GET_PAGE_PROT. Subsequently all __SXXX and __PXXX
> >> macros can be dropped which are no longer needed. While here, this also
> >> localizes arch_vm_get_page_prot() as powerpc_vm_get_page_prot().
> >>
> >> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> >> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> >> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> >> Cc: linux-kernel@xxxxxxxxxxxxxxx
> >> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> >> ---
> >> arch/powerpc/Kconfig | 1 +
> >> arch/powerpc/include/asm/mman.h | 3 +-
> >> arch/powerpc/include/asm/pgtable.h | 19 ------------
> >> arch/powerpc/mm/mmap.c | 47 ++++++++++++++++++++++++++++++
> >> 4 files changed, 49 insertions(+), 21 deletions(-)
> >>
> >> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> >> index b779603978e1..ddb4a3687c05 100644
> >> --- a/arch/powerpc/Kconfig
> >> +++ b/arch/powerpc/Kconfig
> >> @@ -135,6 +135,7 @@ config PPC
> >> select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
> >> select ARCH_HAS_UACCESS_FLUSHCACHE
> >> select ARCH_HAS_UBSAN_SANITIZE_ALL
> >> + select ARCH_HAS_VM_GET_PAGE_PROT
> >> select ARCH_HAVE_NMI_SAFE_CMPXCHG
> >> select ARCH_KEEP_MEMBLOCK
> >> select ARCH_MIGHT_HAVE_PC_PARPORT
> >> diff --git a/arch/powerpc/include/asm/mman.h b/arch/powerpc/include/asm/mman.h
> >> index 7cb6d18f5cd6..7b10c2031e82 100644
> >> --- a/arch/powerpc/include/asm/mman.h
> >> +++ b/arch/powerpc/include/asm/mman.h
> >> @@ -24,7 +24,7 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
> >> }
> >> #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
> >>
> >> -static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
> >> +static inline pgprot_t powerpc_vm_get_page_prot(unsigned long vm_flags)
> >> {
> >> #ifdef CONFIG_PPC_MEM_KEYS
> >> return (vm_flags & VM_SAO) ?
> >> @@ -34,7 +34,6 @@ static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
> >> return (vm_flags & VM_SAO) ? __pgprot(_PAGE_SAO) : __pgprot(0);
> >> #endif
> >> }
> >> -#define arch_vm_get_page_prot(vm_flags) arch_vm_get_page_prot(vm_flags)
> >>
> >> static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
> >> {
> >> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> >> index d564d0ecd4cd..3cbb6de20f9d 100644
> >> --- a/arch/powerpc/include/asm/pgtable.h
> >> +++ b/arch/powerpc/include/asm/pgtable.h
> >> @@ -20,25 +20,6 @@ struct mm_struct;
> >> #include <asm/nohash/pgtable.h>
> >> #endif /* !CONFIG_PPC_BOOK3S */
> >>
> >> -/* Note due to the way vm flags are laid out, the bits are XWR */
> >> -#define __P000 PAGE_NONE
> >> -#define __P001 PAGE_READONLY
> >> -#define __P010 PAGE_COPY
> >> -#define __P011 PAGE_COPY
> >> -#define __P100 PAGE_READONLY_X
> >> -#define __P101 PAGE_READONLY_X
> >> -#define __P110 PAGE_COPY_X
> >> -#define __P111 PAGE_COPY_X
> >> -
> >> -#define __S000 PAGE_NONE
> >> -#define __S001 PAGE_READONLY
> >> -#define __S010 PAGE_SHARED
> >> -#define __S011 PAGE_SHARED
> >> -#define __S100 PAGE_READONLY_X
> >> -#define __S101 PAGE_READONLY_X
> >> -#define __S110 PAGE_SHARED_X
> >> -#define __S111 PAGE_SHARED_X
> >> -
> >> #ifndef __ASSEMBLY__
> >>
> >> #ifndef MAX_PTRS_PER_PGD
> >> diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c
> >> index c475cf810aa8..7f05e7903bd2 100644
> >> --- a/arch/powerpc/mm/mmap.c
> >> +++ b/arch/powerpc/mm/mmap.c
> >> @@ -254,3 +254,50 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
> >> mm->get_unmapped_area = arch_get_unmapped_area_topdown;
> >> }
> >> }
> >> +
> >> +static inline pgprot_t __vm_get_page_prot(unsigned long vm_flags)
> >> +{
> >> + switch (vm_flags & (VM_READ | VM_WRITE | VM_EXEC | VM_SHARED)) {
> >> + case VM_NONE:
> >> + return PAGE_NONE;
> >> + case VM_READ:
> >> + return PAGE_READONLY;
> >> + case VM_WRITE:
> >> + return PAGE_COPY;
> >> + case VM_READ | VM_WRITE:
> >> + return PAGE_COPY;
> >> + case VM_EXEC:
> >> + return PAGE_READONLY_X;
> >> + case VM_EXEC | VM_READ:
> >> + return PAGE_READONLY_X;
> >> + case VM_EXEC | VM_WRITE:
> >> + return PAGE_COPY_X;
> >> + case VM_EXEC | VM_READ | VM_WRITE:
> >> + return PAGE_COPY_X;
> >> + case VM_SHARED:
> >> + return PAGE_NONE;
> >> + case VM_SHARED | VM_READ:
> >> + return PAGE_READONLY;
> >> + case VM_SHARED | VM_WRITE:
> >> + return PAGE_SHARED;
> >> + case VM_SHARED | VM_READ | VM_WRITE:
> >> + return PAGE_SHARED;
> >> + case VM_SHARED | VM_EXEC:
> >> + return PAGE_READONLY_X;
> >> + case VM_SHARED | VM_EXEC | VM_READ:
> >> + return PAGE_READONLY_X;
> >> + case VM_SHARED | VM_EXEC | VM_WRITE:
> >> + return PAGE_SHARED_X;
> >> + case VM_SHARED | VM_EXEC | VM_READ | VM_WRITE:
> >> + return PAGE_SHARED_X;
> >> + default:
> >> + BUILD_BUG();
> >> + }
> >> +}
> >> +
> >> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
> >> +{
> >> + return __pgprot(pgprot_val(__vm_get_page_prot(vm_flags)) |
> >> + pgprot_val(powerpc_vm_get_page_prot(vm_flags)));
> > Any reason to keep powerpc_vm_get_page_prot() rather than open code it
> > here?
> >
> > This applies to other architectures that implement arch_vm_get_page_prot()
> > and/or arch_filter_pgprot() as well.
>
> Just to minimize the code churn ! But I will be happy to open code them
> here (and in other platforms) if that will be preferred.
I think this will be clearer because all the processing will be at one place.
Besides, this way include/asm/pgtable.h becomes shorter and less crowded.
--
Sincerely yours,
Mike.
