Re: [PATCH V5 04/26] sparc/mm: Move protection_map[] inside the platform

Sam Ravnborg
2022-06-27T17:16:15Z

Hi Anshuman,

On Mon, Jun 27, 2022 at 10:28:11AM +0530, Anshuman Khandual wrote:
> 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.
>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: sparclinux@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/sparc/Kconfig | 2 +-
> arch/sparc/include/asm/pgtable_32.h | 19 -------------------
> arch/sparc/include/asm/pgtable_64.h | 19 -------------------
> arch/sparc/mm/init_32.c | 20 ++++++++++++++++++++
> arch/sparc/mm/init_64.c | 3 +++
> 5 files changed, 24 insertions(+), 39 deletions(-)
>
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index ba449c47effd..09f868613a4d 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -13,6 +13,7 @@ config 64BIT
> config SPARC
> bool
> default y
> + select ARCH_HAS_VM_GET_PAGE_PROT
> select ARCH_MIGHT_HAVE_PC_PARPORT if SPARC64 && PCI
> select ARCH_MIGHT_HAVE_PC_SERIO
> select DMA_OPS
> @@ -84,7 +85,6 @@ config SPARC64
> select PERF_USE_VMALLOC
> select ARCH_HAVE_NMI_SAFE_CMPXCHG
> select HAVE_C_RECORDMCOUNT
> - select ARCH_HAS_VM_GET_PAGE_PROT
> select HAVE_ARCH_AUDITSYSCALL
> select ARCH_SUPPORTS_ATOMIC_RMW
> select ARCH_SUPPORTS_DEBUG_PAGEALLOC
> diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
> index 4866625da314..8ff549004fac 100644
> --- a/arch/sparc/include/asm/pgtable_32.h
> +++ b/arch/sparc/include/asm/pgtable_32.h
> @@ -64,25 +64,6 @@ void paging_init(void);
>
> extern unsigned long ptr_in_current_pgd;
>
> -/* xwr */
> -#define __P000 PAGE_NONE
> -#define __P001 PAGE_READONLY
> -#define __P010 PAGE_COPY
> -#define __P011 PAGE_COPY
> -#define __P100 PAGE_READONLY
> -#define __P101 PAGE_READONLY
> -#define __P110 PAGE_COPY
> -#define __P111 PAGE_COPY
> -
> -#define __S000 PAGE_NONE
> -#define __S001 PAGE_READONLY
> -#define __S010 PAGE_SHARED
> -#define __S011 PAGE_SHARED
> -#define __S100 PAGE_READONLY
> -#define __S101 PAGE_READONLY
> -#define __S110 PAGE_SHARED
> -#define __S111 PAGE_SHARED
> -
> /* First physical page can be anywhere, the following is needed so that
> * va-->pa and vice versa conversions work properly without performance
> * hit for all __pa()/__va() operations.
> diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
> index 4679e45c8348..a779418ceba9 100644
> --- a/arch/sparc/include/asm/pgtable_64.h
> +++ b/arch/sparc/include/asm/pgtable_64.h
> @@ -187,25 +187,6 @@ bool kern_addr_valid(unsigned long addr);
> #define _PAGE_SZHUGE_4U _PAGE_SZ4MB_4U
> #define _PAGE_SZHUGE_4V _PAGE_SZ4MB_4V
>
> -/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
> -#define __P000 __pgprot(0)
> -#define __P001 __pgprot(0)
> -#define __P010 __pgprot(0)
> -#define __P011 __pgprot(0)
> -#define __P100 __pgprot(0)
> -#define __P101 __pgprot(0)
> -#define __P110 __pgprot(0)
> -#define __P111 __pgprot(0)
> -
> -#define __S000 __pgprot(0)
> -#define __S001 __pgprot(0)
> -#define __S010 __pgprot(0)
> -#define __S011 __pgprot(0)
> -#define __S100 __pgprot(0)
> -#define __S101 __pgprot(0)
> -#define __S110 __pgprot(0)
> -#define __S111 __pgprot(0)
> -
> #ifndef __ASSEMBLY__
>
> pte_t mk_pte_io(unsigned long, pgprot_t, int, unsigned long);
> diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
> index 1e9f577f084d..8693e4e28b86 100644
> --- a/arch/sparc/mm/init_32.c
> +++ b/arch/sparc/mm/init_32.c
> @@ -302,3 +302,23 @@ void sparc_flush_page_to_ram(struct page *page)
> __flush_page_to_ram(vaddr);
> }
> EXPORT_SYMBOL(sparc_flush_page_to_ram);
> +
> +static pgprot_t protection_map[16] __ro_after_init = {
This can be const - like done for powerpc and others.
sparc32 and sparc64 uses each their own - and I do not see sparc32 do
any modifications to protection_map.

With this change:
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

> + [VM_NONE] = PAGE_NONE,
> + [VM_READ] = PAGE_READONLY,
> + [VM_WRITE] = PAGE_COPY,
> + [VM_WRITE | VM_READ] = PAGE_COPY,
> + [VM_EXEC] = PAGE_READONLY,
> + [VM_EXEC | VM_READ] = PAGE_READONLY,
> + [VM_EXEC | VM_WRITE] = PAGE_COPY,
> + [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
> + [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,
> + [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
> + [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
> + [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
> +};
> +DECLARE_VM_GET_PAGE_PROT
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index f6174df2d5af..d6faee23c77d 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -2634,6 +2634,9 @@ void vmemmap_free(unsigned long start, unsigned long end,
> }
> #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>
> +/* These are actually filled in at boot time by sun4{u,v}_pgprot_init() */
> +static pgprot_t protection_map[16] __ro_after_init;
> +
> static void prot_init_common(unsigned long page_none,
> unsigned long page_shared,
> unsigned long page_copy,
> --
> 2.25.1