Le 24/06/2022 à 06:43, Anshuman Khandual a écrit :
> This moves protection_map[] inside the platform and while here, also enable
> ARCH_HAS_VM_GET_PAGE_PROT on 32 bit platforms via DECLARE_VM_GET_PAGE_PROT.
Not only 32 bit platforms, also nohash 64 (aka book3e/64)
>
> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
> Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> arch/powerpc/Kconfig | 2 +-
> arch/powerpc/include/asm/pgtable.h | 20 +-------------------
> arch/powerpc/mm/pgtable.c | 24 ++++++++++++++++++++++++
> 3 files changed, 26 insertions(+), 20 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index c2ce2e60c8f0..1035d172c7dd 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -140,7 +140,7 @@ 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 if PPC_BOOK3S_64
> + 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/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> index d564d0ecd4cd..bf98db844579 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
> @@ -79,6 +60,7 @@ extern void paging_init(void);
> void poking_init(void);
>
> extern unsigned long ioremap_bot;
> +extern pgprot_t protection_map[16] __ro_after_init;
>
> /*
> * kern_addr_valid is intended to indicate whether an address is a valid
> diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
> index e6166b71d36d..618f30d35b17 100644
> --- a/arch/powerpc/mm/pgtable.c
> +++ b/arch/powerpc/mm/pgtable.c
> @@ -472,3 +472,27 @@ pte_t *__find_linux_pte(pgd_t *pgdir, unsigned long ea,
> return ret_pte;
> }
> EXPORT_SYMBOL_GPL(__find_linux_pte);
> +
> +/* Note due to the way vm flags are laid out, the bits are XWR */
> +pgprot_t protection_map[16] __ro_after_init = {
I can't see any place where protection_map[] gets modified. This could
be made const.
> + [VM_NONE] = PAGE_NONE,
> + [VM_READ] = PAGE_READONLY,
> + [VM_WRITE] = PAGE_COPY,
> + [VM_WRITE | VM_READ] = PAGE_COPY,
> + [VM_EXEC] = PAGE_READONLY_X,
> + [VM_EXEC | VM_READ] = PAGE_READONLY_X,
> + [VM_EXEC | VM_WRITE] = PAGE_COPY_X,
> + [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_X,
> + [VM_SHARED] = PAGE_NONE,
> + [VM_SHARED | VM_READ] = PAGE_READONLY,
> + [VM_SHARED | VM_WRITE] = PAGE_SHARED,
> + [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
> + [VM_SHARED | VM_EXEC] = PAGE_READONLY_X,
> + [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY_X,
> + [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED_X,
> + [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_X
> +};
> +
> +#ifndef CONFIG_PPC_BOOK3S_64
> +DECLARE_VM_GET_PAGE_PROT
> +#endif
