linux-kernel - Re: [PATCH v3 1/3] ioremap: Update pgtable free interfaces with addr

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Date:   Tue, 20 Mar 2018 12:34:20 +0530
From:   Chintan Pandya <cpandya@...eaurora.org>
To:     "Kani, Toshi" <toshi.kani@....com>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "catalin.marinas@....com" <catalin.marinas@....com>,
        "will.deacon@....com" <will.deacon@....com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "takahiro.akashi@...aro.org" <takahiro.akashi@...aro.org>,
        "james.morse@....com" <james.morse@....com>,
        "kristina.martsenko@....com" <kristina.martsenko@....com>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "marc.zyngier@....com" <marc.zyngier@....com>,
        "arnd@...db.de" <arnd@...db.de>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
Subject: Re: [PATCH v3 1/3] ioremap: Update pgtable free interfaces with addr



On 3/20/2018 12:31 AM, Kani, Toshi wrote:
> On Mon, 2018-03-19 at 18:10 +0530, Chintan Pandya wrote:
>> This patch ("mm/vmalloc: Add interfaces to free unmapped
>> page table") adds following 2 interfaces to free the page
>> table in case we implement huge mapping.
>>
>> pud_free_pmd_page() and pmd_free_pte_page()
>>
>> Some architectures (like arm64) needs to do proper TLB
>> maintanance after updating pagetable entry even in map.
>> Why ? Read this,
>> https://patchwork.kernel.org/patch/10134581/
>>
>> Pass 'addr' in these interfaces so that proper TLB ops
>> can be performed.
>>
>> Signed-off-by: Chintan Pandya <cpandya@...eaurora.org>
>   :
>> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
>> index 34cda7e..20b0322 100644
>> --- a/arch/x86/mm/pgtable.c
>> +++ b/arch/x86/mm/pgtable.c
>> @@ -710,7 +710,7 @@ int pmd_clear_huge(pmd_t *pmd)
>>    * Context: The pud range has been unmaped and TLB purged.
>>    * Return: 1 if clearing the entry succeeded. 0 otherwise.
>>    */
>> -int pud_free_pmd_page(pud_t *pud)
>> +int pud_free_pmd_page(pud_t *pud, unsigned long addr)
> 
> Please update the function header as well.  Same for pmd.
> 
> + * @addr: Virtual address associated with pud.
Noted.
> 
> --- a/include/asm-generic/pgtable.h
>> +++ b/include/asm-generic/pgtable.h
>> @@ -983,8 +983,8 @@ static inline int p4d_clear_huge(p4d_t *p4d)
>>   int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
>>   int pud_clear_huge(pud_t *pud);
>>   int pmd_clear_huge(pmd_t *pmd);
>> -int pud_free_pmd_page(pud_t *pud);
>> -int pmd_free_pte_page(pmd_t *pmd);
>> +int pud_free_pmd_page(pud_t *pud, unsigned long addr);
>> +int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
>>   #else	/* !CONFIG_HAVE_ARCH_HUGE_VMAP */
>>   static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t
> prot)
>>   {
>> @@ -1010,11 +1010,11 @@ static inline int pmd_clear_huge(pmd_t *pmd)
>>   {
>>   	return 0;
>>   }
>> -static inline int pud_free_pmd_page(pud_t *pud)
>> +static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
>>   {
>>   	return 0;
>>   }
>> -static inline int pmd_free_pte_page(pud_t *pmd)
>> +static inline int pmd_free_pte_page(pud_t *pmd, unsigned long addr)
> 
> Please base your patches on top of the mm tree or at least pick up
> 8cab93de994f6 in the mm tree.  Andrew fixed the typo; the 'pud_t' above
> should have been 'pmd_t'.

Right. Noted.

> 
> Thanks,
> -Toshi
> 

Chintan
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