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Date:   Mon, 24 Jan 2022 11:21:38 -0700
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Subject: Re: [RFC V1 06/31] sparc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
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To:     Anshuman Khandual <anshuman.khandual@arm.com>, linux-mm@kvack.org
Cc:     linux-kernel@vger.kernel.org, hch@infradead.org,
        akpm@linux-foundation.org, "David S. Miller" <davem@davemloft.net>,
        sparclinux@vger.kernel.org
References: <1643029028-12710-1-git-send-email-anshuman.khandual@arm.com>
 <1643029028-12710-7-git-send-email-anshuman.khandual@arm.com>
From:   Khalid Aziz <khalid.aziz@oracle.com>
In-Reply-To: <1643029028-12710-7-git-send-email-anshuman.khandual@arm.com>
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On 1/24/22 05:56, 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.
> 
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Khalid Aziz <khalid.aziz@oracle.com>
> Cc: sparclinux@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---


Look like reasonable changes to me.

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>

>   arch/sparc/Kconfig                  |  2 +
>   arch/sparc/include/asm/mman.h       |  1 -
>   arch/sparc/include/asm/pgtable_32.h | 19 --------
>   arch/sparc/include/asm/pgtable_64.h | 19 --------
>   arch/sparc/mm/init_32.c             | 41 +++++++++++++++++
>   arch/sparc/mm/init_64.c             | 71 +++++++++++++++++++++--------
>   6 files changed, 95 insertions(+), 58 deletions(-)
> 
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index 1cab1b284f1a..ff29156f2380 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -59,6 +59,7 @@ config SPARC32
>   	select HAVE_UID16
>   	select OLD_SIGACTION
>   	select ZONE_DMA
> +	select ARCH_HAS_VM_GET_PAGE_PROT
>   
>   config SPARC64
>   	def_bool 64BIT
> @@ -84,6 +85,7 @@ 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/mman.h b/arch/sparc/include/asm/mman.h
> index 274217e7ed70..874d21483202 100644
> --- a/arch/sparc/include/asm/mman.h
> +++ b/arch/sparc/include/asm/mman.h
> @@ -46,7 +46,6 @@ static inline unsigned long sparc_calc_vm_prot_bits(unsigned long prot)
>   	}
>   }
>   
> -#define arch_vm_get_page_prot(vm_flags) sparc_vm_get_page_prot(vm_flags)
>   static inline pgprot_t sparc_vm_get_page_prot(unsigned long vm_flags)
>   {
>   	return (vm_flags & VM_SPARC_ADI) ? __pgprot(_PAGE_MCD_4V) : __pgprot(0);
> diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
> index ffccfe3b22ed..060a435f96d6 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..efb3d6e6d7f6 100644
> --- a/arch/sparc/mm/init_32.c
> +++ b/arch/sparc/mm/init_32.c
> @@ -302,3 +302,44 @@ void sparc_flush_page_to_ram(struct page *page)
>   		__flush_page_to_ram(vaddr);
>   }
>   EXPORT_SYMBOL(sparc_flush_page_to_ram);
> +
> +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;
> +	case VM_EXEC | VM_READ:
> +		return PAGE_READONLY;
> +	case VM_EXEC | VM_WRITE:
> +		return PAGE_COPY;
> +	case VM_EXEC | VM_READ | VM_WRITE:
> +		return PAGE_COPY;
> +	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;
> +	case VM_SHARED | VM_EXEC | VM_READ:
> +		return PAGE_READONLY;
> +	case VM_SHARED | VM_EXEC | VM_WRITE:
> +		return PAGE_SHARED;
> +	case VM_SHARED | VM_EXEC | VM_READ | VM_WRITE:
> +		return PAGE_SHARED;
> +	default:
> +		BUILD_BUG();
> +	}
> +}
> +EXPORT_SYMBOL(vm_get_page_prot);
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index 1b23639e2fcd..46b5366f7f69 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -50,6 +50,7 @@
>   #include <asm/cpudata.h>
>   #include <asm/setup.h>
>   #include <asm/irq.h>
> +#include <asm/mman.h>
>   
>   #include "init_64.h"
>   
> @@ -2641,29 +2642,13 @@ static void prot_init_common(unsigned long page_none,
>   {
>   	PAGE_COPY = __pgprot(page_copy);
>   	PAGE_SHARED = __pgprot(page_shared);
> -
> -	protection_map[0x0] = __pgprot(page_none);
> -	protection_map[0x1] = __pgprot(page_readonly & ~page_exec_bit);
> -	protection_map[0x2] = __pgprot(page_copy & ~page_exec_bit);
> -	protection_map[0x3] = __pgprot(page_copy & ~page_exec_bit);
> -	protection_map[0x4] = __pgprot(page_readonly);
> -	protection_map[0x5] = __pgprot(page_readonly);
> -	protection_map[0x6] = __pgprot(page_copy);
> -	protection_map[0x7] = __pgprot(page_copy);
> -	protection_map[0x8] = __pgprot(page_none);
> -	protection_map[0x9] = __pgprot(page_readonly & ~page_exec_bit);
> -	protection_map[0xa] = __pgprot(page_shared & ~page_exec_bit);
> -	protection_map[0xb] = __pgprot(page_shared & ~page_exec_bit);
> -	protection_map[0xc] = __pgprot(page_readonly);
> -	protection_map[0xd] = __pgprot(page_readonly);
> -	protection_map[0xe] = __pgprot(page_shared);
> -	protection_map[0xf] = __pgprot(page_shared);
>   }
>   
> +static unsigned long page_none, page_shared, page_copy, page_readonly;
> +static unsigned long page_exec_bit;
> +
>   static void __init sun4u_pgprot_init(void)
>   {
> -	unsigned long page_none, page_shared, page_copy, page_readonly;
> -	unsigned long page_exec_bit;
>   	int i;
>   
>   	PAGE_KERNEL = __pgprot (_PAGE_PRESENT_4U | _PAGE_VALID |
> @@ -3183,3 +3168,51 @@ void copy_highpage(struct page *to, struct page *from)
>   	}
>   }
>   EXPORT_SYMBOL(copy_highpage);
> +
> +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 __pgprot(page_none);
> +	case VM_READ:
> +		return __pgprot(page_readonly & ~page_exec_bit);
> +	case VM_WRITE:
> +		return __pgprot(page_copy & ~page_exec_bit);
> +	case VM_READ | VM_WRITE:
> +		return __pgprot(page_copy & ~page_exec_bit);
> +	case VM_EXEC:
> +		return __pgprot(page_readonly);
> +	case VM_EXEC | VM_READ:
> +		return __pgprot(page_readonly);
> +	case VM_EXEC | VM_WRITE:
> +		return __pgprot(page_copy);
> +	case VM_EXEC | VM_READ | VM_WRITE:
> +		return __pgprot(page_copy);
> +	case VM_SHARED:
> +		return __pgprot(page_none);
> +	case VM_SHARED | VM_READ:
> +		return __pgprot(page_readonly & ~page_exec_bit);
> +	case VM_SHARED | VM_WRITE:
> +		return __pgprot(page_shared & ~page_exec_bit);
> +	case VM_SHARED | VM_READ | VM_WRITE:
> +		return __pgprot(page_shared & ~page_exec_bit);
> +	case VM_SHARED | VM_EXEC:
> +		return __pgprot(page_readonly);
> +	case VM_SHARED | VM_EXEC | VM_READ:
> +		return __pgprot(page_readonly);
> +	case VM_SHARED | VM_EXEC | VM_WRITE:
> +		return __pgprot(page_shared);
> +	case VM_SHARED | VM_EXEC | VM_READ | VM_WRITE:
> +		return __pgprot(page_shared);
> +	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(sparc_vm_get_page_prot(vm_flags)));
> +
> +}
> +EXPORT_SYMBOL(vm_get_page_prot);
>