From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Mike Rapoport <rppt@kernel.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
hch@infradead.org, akpm@linux-foundation.org
Subject: Re: [RFC V1 02/31] mm/mmap: Clarify protection_map[] indices
Date: Mon, 31 Jan 2022 08:55:12 +0530 [thread overview]
Message-ID: <904f9623-0f02-9530-1d66-017baa082349@arm.com> (raw)
In-Reply-To: <YfKSn6u3YsErB/Ky@kernel.org>
On 1/27/22 6:09 PM, Mike Rapoport wrote:
> On Mon, Jan 24, 2022 at 06:26:39PM +0530, Anshuman Khandual wrote:
>> protection_map[] maps vm_flags access combinations into page protection
>> value as defined by the platform via __PXXX and __SXXX macros. The array
>> indices in protection_map[], represents vm_flags access combinations but
>> it's not very intuitive to derive. This makes it clear and explicit.
>
> The protection_map is going to be removed in one of the next patches, why
> bother with this patch at all?
This makes the transition from protection_map[] into __vm_get_page_prot()
more intuitive, where protection_map[] gets dropped. This helps platforms
(first ones subscribing ARCH_HAS_VM_GET_PAGE_PROT before this drop) create
/formulate the required switch case elements in their vm_get_page_prot().
The existing protection_map[] is not clear in demonstrating how exactly
the vm_flags combination is mapped into page protection map. This helps
clarify the underlying switch before we move on defining it on platforms.
>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> mm/mmap.c | 18 ++++++++++++++++--
>> 1 file changed, 16 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/mmap.c b/mm/mmap.c
>> index 1e8fdb0b51ed..254d716220df 100644
>> --- a/mm/mmap.c
>> +++ b/mm/mmap.c
>> @@ -102,8 +102,22 @@ static void unmap_region(struct mm_struct *mm,
>> * x: (yes) yes
>> */
>> pgprot_t protection_map[16] __ro_after_init = {
>> - __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
>> - __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
>> + [VM_NONE] = __P000,
>> + [VM_READ] = __P001,
>> + [VM_WRITE] = __P010,
>> + [VM_READ|VM_WRITE] = __P011,
>> + [VM_EXEC] = __P100,
>> + [VM_EXEC|VM_READ] = __P101,
>> + [VM_EXEC|VM_WRITE] = __P110,
>> + [VM_EXEC|VM_READ|VM_WRITE] = __P111,
>> + [VM_SHARED] = __S000,
>> + [VM_SHARED|VM_READ] = __S001,
>> + [VM_SHARED|VM_WRITE] = __S010,
>> + [VM_SHARED|VM_READ|VM_WRITE] = __S011,
>> + [VM_SHARED|VM_EXEC] = __S100,
>> + [VM_SHARED|VM_READ|VM_EXEC] = __S101,
>> + [VM_SHARED|VM_WRITE|VM_EXEC] = __S110,
>> + [VM_SHARED|VM_READ|VM_WRITE|VM_EXEC] = __S111
>> };
>>
>> #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT
>> --
>> 2.25.1
>>
>>
>
next prev parent reply other threads:[~2022-01-31 3:25 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 12:56 [RFC V1 00/31] mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 01/31] mm/debug_vm_pgtable: Directly use vm_get_page_prot() Anshuman Khandual
2022-01-26 7:15 ` Christoph Hellwig
2022-01-27 4:16 ` Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 02/31] mm/mmap: Clarify protection_map[] indices Anshuman Khandual
2022-01-26 7:16 ` Christoph Hellwig
2022-01-27 4:07 ` Anshuman Khandual
2022-01-27 12:39 ` Mike Rapoport
2022-01-31 3:25 ` Anshuman Khandual [this message]
2022-02-05 9:10 ` Firo Yang
2022-02-09 3:23 ` Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 03/31] mm/mmap: Add new config ARCH_HAS_VM_GET_PAGE_PROT Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 04/31] powerpc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT Anshuman Khandual
2022-02-03 18:15 ` Mike Rapoport
2022-02-04 2:57 ` Anshuman Khandual
2022-02-04 4:44 ` Mike Rapoport
2022-01-24 12:56 ` [RFC V1 05/31] arm64/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 06/31] sparc/mm: " Anshuman Khandual
2022-01-24 12:58 ` David Miller
2022-01-24 18:21 ` Khalid Aziz
2022-01-24 12:56 ` [RFC V1 07/31] mips/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 08/31] m68k/mm: " Anshuman Khandual
2022-01-24 14:13 ` Andreas Schwab
2022-01-25 3:42 ` Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 09/31] arm/mm: " Anshuman Khandual
2022-01-24 17:06 ` Russell King (Oracle)
2022-01-25 3:36 ` Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 10/31] x86/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 11/31] mm/mmap: Drop protection_map[] Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 12/31] mm/mmap: Drop arch_filter_pgprot() Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 13/31] mm/mmap: Drop arch_vm_get_page_pgprot() Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 14/31] s390/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 15/31] riscv/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 16/31] alpha/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 17/31] sh/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 18/31] arc/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 19/31] csky/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 20/31] extensa/mm: " Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 21/31] parisc/mm: " Anshuman Khandual
2022-01-25 16:53 ` Rolf Eike Beer
2022-01-27 4:06 ` Anshuman Khandual
2022-01-24 12:56 ` [RFC V1 22/31] openrisc/mm: " Anshuman Khandual
2022-02-05 6:58 ` [OpenRISC] " Stafford Horne
2022-01-24 12:57 ` [RFC V1 23/31] um/mm: " Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 24/31] microblaze/mm: " Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 25/31] nios2/mm: " Anshuman Khandual
2022-01-26 16:38 ` Dinh Nguyen
2022-01-24 12:57 ` [RFC V1 26/31] hexagon/mm: " Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 27/31] nds32/mm: " Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 28/31] ia64/mm: " Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 29/31] mm/mmap: Drop generic vm_get_page_prot() Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 30/31] mm/mmap: Drop ARCH_HAS_VM_GET_PAGE_PROT Anshuman Khandual
2022-01-24 12:57 ` [RFC V1 31/31] mm/mmap: Define macros for vm_flags access permission combinations Anshuman Khandual
2022-02-03 5:24 ` Anshuman Khandual
2022-01-27 12:38 ` [RFC V1 00/31] mm/mmap: Drop protection_map[] and platform's __SXXX/__PXXX requirements Mike Rapoport
2022-01-31 3:35 ` Anshuman Khandual
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