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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	akpm@linux-foundation.org, suzuki.poulose@arm.com,
	mark.rutland@arm.com, will@kernel.org, maz@kernel.org,
	james.morse@arm.com, steven.price@arm.com
Subject: Re: [RFC V2 01/10] mm/mmap: Dynamically initialize protection_map[]
Date: Thu, 12 Aug 2021 14:45:37 +0530	[thread overview]
Message-ID: <d52e8af9-61af-45c2-837b-5a489e7e2916@arm.com> (raw)
In-Reply-To: <20210805170318.GB6719@arm.com>



On 8/5/21 10:33 PM, Catalin Marinas wrote:
> On Mon, Jul 26, 2021 at 12:07:16PM +0530, Anshuman Khandual wrote:
>> The protection_map[] elements (__PXXX and __SXXX) might sometimes contain
>> runtime variables in certain platforms like arm64 preventing a successful
>> build because of the current static initialization. So it just defers the
>> initialization until mmmap_init() via a new helper init_protection_map().
>>
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>>  mm/mmap.c | 26 ++++++++++++++++++++++----
>>  1 file changed, 22 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/mmap.c b/mm/mmap.c
>> index ca54d36..a95b078 100644
>> --- a/mm/mmap.c
>> +++ b/mm/mmap.c
>> @@ -100,10 +100,7 @@ static void unmap_region(struct mm_struct *mm,
>>   *								w: (no) no
>>   *								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
>> -};
>> +pgprot_t protection_map[16] __ro_after_init;
> 
> Mips, x86, sparc, arm32, m68k all adjust protection_map[] during boot.
> Could we do something similar here and avoid changing the generic code?

If __P[000..111] and __S[000..111] be made dummy values (e.g 0 or something
standard prot temporarily), hence the compilation problem could be avoided.
Later in the platform code, protection_map[] could be adjusted with actual
prot values which would involve variable.

  reply	other threads:[~2021-08-12  9:14 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-26  6:37 [RFC V2 00/10] arm64/mm: Enable FEAT_LPA2 (52 bits PA support on 4K|16K pages) Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 01/10] mm/mmap: Dynamically initialize protection_map[] Anshuman Khandual
2021-08-05 17:03   ` Catalin Marinas
2021-08-12  9:15     ` Anshuman Khandual [this message]
2021-08-13  7:16       ` Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 02/10] arm64/mm: Consolidate TCR_EL1 fields Anshuman Khandual
2021-08-05 17:05   ` Catalin Marinas
2021-07-26  6:37 ` [RFC V2 03/10] arm64/mm: Add FEAT_LPA2 specific TCR_EL1.DS field Anshuman Khandual
2021-08-05 17:06   ` Catalin Marinas
2021-07-26  6:37 ` [RFC V2 04/10] arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2] Anshuman Khandual
2021-08-05 17:06   ` Catalin Marinas
2021-07-26  6:37 ` [RFC V2 05/10] arm64/mm: Add CONFIG_ARM64_PA_BITS_52_[LPA|LPA2] Anshuman Khandual
2021-08-05 17:25   ` Catalin Marinas
2021-08-12 10:09     ` Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 06/10] arm64/mm: Add FEAT_LPA2 specific encoding Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 07/10] arm64/mm: Detect and enable FEAT_LPA2 Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 08/10] arm64/mm: Add FEAT_LPA2 specific PTE_SHARED and PMD_SECT_S Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 09/10] arm64/mm: Add FEAT_LPA2 specific fallback (48 bits PA) when not implemented Anshuman Khandual
2021-07-26  6:37 ` [RFC V2 10/10] arm64/mm: Enable CONFIG_ARM64_PA_BITS_52 on CONFIG_ARM64_[4K|16K]_PAGES Anshuman Khandual
2021-08-05 17:23   ` Catalin Marinas
2021-08-12  9:13     ` Anshuman Khandual

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