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From: Robin Murphy <robin.murphy@arm.com>
To: Will Deacon <will.deacon@arm.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
	catalin.marinas@arm.com, anshuman.khandual@arm.com,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 4/4] arm64: mm: Implement pte_devmap support
Date: Fri, 24 May 2019 19:38:45 +0100	[thread overview]
Message-ID: <9ef54c1b-b9a5-ed13-b9d6-65e7c4af0a75@arm.com> (raw)
In-Reply-To: <20190524180805.GA9697@fuggles.cambridge.arm.com>

On 24/05/2019 19:08, Will Deacon wrote:
> On Thu, May 23, 2019 at 04:03:16PM +0100, Robin Murphy wrote:
>> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
>> index 2c41b04708fe..a6378625d47c 100644
>> --- a/arch/arm64/include/asm/pgtable.h
>> +++ b/arch/arm64/include/asm/pgtable.h
>> @@ -90,6 +90,7 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
>>   #define pte_write(pte)		(!!(pte_val(pte) & PTE_WRITE))
>>   #define pte_user_exec(pte)	(!(pte_val(pte) & PTE_UXN))
>>   #define pte_cont(pte)		(!!(pte_val(pte) & PTE_CONT))
>> +#define pte_devmap(pte)		(!!(pte_val(pte) & PTE_DEVMAP))
>>   
>>   #define pte_cont_addr_end(addr, end)						\
>>   ({	unsigned long __boundary = ((addr) + CONT_PTE_SIZE) & CONT_PTE_MASK;	\
>> @@ -217,6 +218,11 @@ static inline pmd_t pmd_mkcont(pmd_t pmd)
>>   	return __pmd(pmd_val(pmd) | PMD_SECT_CONT);
>>   }
>>   
>> +static inline pte_t pte_mkdevmap(pte_t pte)
>> +{
>> +	return set_pte_bit(pte, __pgprot(PTE_DEVMAP));
>> +}
>> +
>>   static inline void set_pte(pte_t *ptep, pte_t pte)
>>   {
>>   	WRITE_ONCE(*ptep, pte);
>> @@ -381,6 +387,9 @@ static inline int pmd_protnone(pmd_t pmd)
>>   
>>   #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
>>   
>> +#define pmd_devmap(pmd)		pte_devmap(pmd_pte(pmd))
>> +#define pmd_mkdevmap(pmd)	pte_pmd(pte_mkdevmap(pmd_pte(pmd)))
>> +
>>   #define __pmd_to_phys(pmd)	__pte_to_phys(pmd_pte(pmd))
>>   #define __phys_to_pmd_val(phys)	__phys_to_pte_val(phys)
>>   #define pmd_pfn(pmd)		((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT)
>> @@ -537,6 +546,11 @@ static inline phys_addr_t pud_page_paddr(pud_t pud)
>>   	return __pud_to_phys(pud);
>>   }
>>   
>> +static inline int pud_devmap(pud_t pud)
>> +{
>> +	return 0;
>> +}
>> +
>>   /* Find an entry in the second-level page table. */
>>   #define pmd_index(addr)		(((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
>>   
>> @@ -624,6 +638,11 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
>>   
>>   #define pgd_ERROR(pgd)		__pgd_error(__FILE__, __LINE__, pgd_val(pgd))
>>   
>> +static inline int pgd_devmap(pgd_t pgd)
>> +{
>> +	return 0;
>> +}
> 
> I think you need to guard this and pXd_devmap() with
> CONFIG_TRANSPARENT_HUGEPAGE, otherwise you'll conflict with the dummy
> definitions in mm.h and the build will fail.

Ah, right you are - I got as far as catching similar issues with 
CONFIG_PGTABLE_LEVELS, but apparently I failed to spot the !THP guards 
in x86 and powerpc. Let me give this one a tweak and test a wider range 
of configs...

Robin.

  reply	other threads:[~2019-05-24 18:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23 15:03 [PATCH v3 0/4] Devmap cleanups + arm64 support Robin Murphy
2019-05-23 15:03 ` [PATCH v3 1/4] mm/memremap: Rename and consolidate SECTION_SIZE Robin Murphy
2019-05-23 15:03 ` [PATCH v3 2/4] mm: clean up is_device_*_page() definitions Robin Murphy
2019-05-23 15:03 ` [PATCH v3 3/4] mm: introduce ARCH_HAS_PTE_DEVMAP Robin Murphy
2019-05-23 15:03 ` [PATCH v3 4/4] arm64: mm: Implement pte_devmap support Robin Murphy
2019-05-24 18:08   ` Will Deacon
2019-05-24 18:38     ` Robin Murphy [this message]
2019-05-27  6:23     ` Anshuman Khandual
2019-05-28 13:46   ` [PATCH v3.1 " Robin Murphy
2019-05-29 10:03     ` Will Deacon
2019-06-26  7:35 ` [PATCH v3 0/4] Devmap cleanups + arm64 support Christoph Hellwig
2019-06-26 12:31   ` Mark Rutland
2019-06-26 15:38     ` Christoph Hellwig
2019-06-26 15:45       ` Jason Gunthorpe
2019-06-27  3:35         ` Andrew Morton
2019-07-04 18:53           ` Andrew Morton
2019-07-04 19:59             ` Jason Gunthorpe
2019-07-04 20:53               ` Andrew Morton
2019-07-04 21:28                 ` Jason Gunthorpe
2019-07-05 15:47                   ` Jason Gunthorpe
2019-07-04 20:54               ` Robin Murphy
2019-07-04 21:13                 ` Andrew Morton
2019-07-05 11:16                   ` Robin Murphy
2019-07-04 23:37               ` Dan Williams
2019-07-05 12:32                 ` Jason Gunthorpe

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