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

Anshuman Khandual
2022-06-28T03:12:49Z

On 6/27/22 22:44, Sam Ravnborg wrote:
> 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.

Indeed protection_map[] arrays are independent both for sparc32 and spacr64.
sparc32 platform never changes the protection_map[] array during boot. Sure,
will make it into a const instead. Thanks for pointing this out.

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