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From: maobibo <maobibo@loongson.cn>
To: Huang Pei <huangpei@loongson.cn>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	ambrosehua@gmail.com, Andrew Morton <akpm@linux-foundation.org>,
	linux-mips@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-mm@kvack.org, Jiaxun Yang <jiaxun.yang@flygoat.com>,
	Paul Burton <paulburton@kernel.org>,
	Li Xuefeng <lixuefeng@loongson.cn>,
	Yang Tiezhu <yangtiezhu@loongson.cn>,
	Gao Juxin <gaojuxin@loongson.cn>,
	Fuxin Zhang <zhangfx@lemote.com>, Huacai Chen <chenhc@lemote.com>
Subject: Re: [PATCH] MIPS: make userspace mapping young by default
Date: Mon, 7 Sep 2020 21:10:41 +0800	[thread overview]
Message-ID: <3802163b-0182-9b5e-4230-1b337ccba361@loongson.cn> (raw)
In-Reply-To: <20200907103551.2pkntwm66t3yma6u@ambrosehua-HP-xw6600-Workstation>



On 09/07/2020 06:35 PM, Huang Pei wrote:
> On Mon, Sep 07, 2020 at 04:50:45PM +0800, maobibo wrote:
>> Sorry for the late reply.
>>
>> Would you like to remove definition of macro pte_sw_mkyoung in header
>> file include/linux/pgtable.h, since it is not used any more.
>>
>> The others look good to me.
>>
>> regards
>> bibo,mao
>>
>> On 09/04/2020 04:49 PM, Huang Pei wrote:
>>> This version removes pte_sw_mkyoung without polluting MM code and covers
>>> both no-RIXI and RIXI MIPS CPUs and makes page fault delay of MIPS on par
>>> with other architecture 
>>>
>>> MIPS page fault path take 3 exceptions (1 TLB Miss + 2 TLB Invalid), but
>>> the second TLB Invalid exception is just triggered by __update_tlb from
>>> do_page_fault writing tlb without _PAGE_VALID set. By making userspace
>>> mapping young by default, aka _PAGE_VALID and _PAGE_ACCESSED both set in
>>> prot, it only take 1 TLB Miss + 1 TLB Invalid exceptions
>>>
>>> [1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email
>>> -maobibo@loongson.cn/
>>>
>>> Co-developed-by: Bibo Mao <maobibo@loonson.cn>
>>> Co-developed-by: Huang Pei <huangpei@loongson.cn>
>>> Signed-off-by: Huang Pei <huangpei@loongson.cn>
>>> ---
>>>  arch/mips/include/asm/pgtable.h | 32 +++++++++++++++-----------------
>>>  arch/mips/mm/cache.c            | 25 +++++++++++++------------
>>>  mm/memory.c                     |  3 ---
>>>  3 files changed, 28 insertions(+), 32 deletions(-)
>>>
>>> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
>>> index dd7a0f552cac..aaafe3d6a0a1 100644
>>> --- a/arch/mips/include/asm/pgtable.h
>>> +++ b/arch/mips/include/asm/pgtable.h
>>> @@ -25,22 +25,22 @@
>>>  struct mm_struct;
>>>  struct vm_area_struct;
>>>  
>>> -#define PAGE_NONE	__pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
>>> -				 _page_cachable_default)
>>> -#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
>>> -				 _page_cachable_default)
>>> -#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
>>> -				 _page_cachable_default)
>>> -#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | \
>>> -				 _page_cachable_default)
>>> -#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
>>> -				 _PAGE_GLOBAL | _page_cachable_default)
>>> -#define PAGE_KERNEL_NC	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
>>> -				 _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
>>> -#define PAGE_USERIO	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
>>> -				 _page_cachable_default)
>>> +#define PAGE_NONE      __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
>>> +                                _page_cachable_default)
>>> +#define PAGE_SHARED    __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
>>> +                                __READABLE | _page_cachable_default)
>>> +#define PAGE_COPY      __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \
>>> +                                __READABLE | _page_cachable_default)
>>> +#define PAGE_READONLY  __pgprot(_PAGE_PRESENT |  __READABLE | \
>>> +                                _page_cachable_default)
>>> +#define PAGE_KERNEL    __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
>>> +                                _PAGE_GLOBAL | _page_cachable_default)
>>> +#define PAGE_KERNEL_NC __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
>>> +                                _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
>>> +#define PAGE_USERIO    __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
>>> +                                _page_cachable_default)
>>>  #define PAGE_KERNEL_UNCACHED __pgprot(_PAGE_PRESENT | __READABLE | \
>>> -			__WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
>>> +                       __WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
>>>  
>>>  /*
>>>   * If _PAGE_NO_EXEC is not defined, we can't do page protection for
>>> @@ -414,8 +414,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
>>>  	return pte;
>>>  }
>>>  
>>> -#define pte_sw_mkyoung	pte_mkyoung
>>> -
>>>  #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
>>>  static inline int pte_huge(pte_t pte)	{ return pte_val(pte) & _PAGE_HUGE; }
>>>  
>>> diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
>>> index 3e81ba000096..ed75f2871aad 100644
>>> --- a/arch/mips/mm/cache.c
>>> +++ b/arch/mips/mm/cache.c
>>> @@ -159,22 +159,23 @@ static inline void setup_protection_map(void)
>>>  {
>>>  	if (cpu_has_rixi) {
>>>  		protection_map[0]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
>>> -		protection_map[1]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
>>> +		protection_map[1]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
>>>  		protection_map[2]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
>>> -		protection_map[3]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
>>> -		protection_map[4]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
>>> -		protection_map[5]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
>>> -		protection_map[6]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
>>> -		protection_map[7]  = __pgprot(_page_cachable_default | _PAGE_PRESENT);
>>> +		protection_map[3]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
>>> +		protection_map[4]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>>> +		protection_map[5]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>>> +		protection_map[6]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>>> +		protection_map[7]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>>>  
>>>  		protection_map[8]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ);
>>> -		protection_map[9]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC);
>>> +		protection_map[9]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
>>>  		protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ);
>>> -		protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE);
>>> -		protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
>>> -		protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT);
>>> -		protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
>>> -		protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE);
>>> +		protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | __READABLE);
>>> +		protection_map[12]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>>> +		protection_map[13]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | __READABLE);
>>> +		protection_map[14]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
>>> +		protection_map[15]  = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | __READABLE);
>>> +
>>>  
>>>  	} else {
>>>  		protection_map[0] = PAGE_NONE;
>>> diff --git a/mm/memory.c b/mm/memory.c
>>> index 602f4283122f..5100ab5bcf77 100644
>>> --- a/mm/memory.c
>>> +++ b/mm/memory.c
>>> @@ -2705,7 +2705,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
>>>  		}
>>>  		flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
>>>  		entry = mk_pte(new_page, vma->vm_page_prot);
>>> -		entry = pte_sw_mkyoung(entry);
>>>  		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
>>>  		/*
>>>  		 * Clear the pte entry and flush it first, before updating the
>>> @@ -3386,7 +3385,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
>>>  	__SetPageUptodate(page);
>>>  
>>>  	entry = mk_pte(page, vma->vm_page_prot);
>>> -	entry = pte_sw_mkyoung(entry);
>>>  	if (vma->vm_flags & VM_WRITE)
>>>  		entry = pte_mkwrite(pte_mkdirty(entry));
>>>  
>>> @@ -3661,7 +3659,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct page *page)
>>>  
>>>  	flush_icache_page(vma, page);
>>>  	entry = mk_pte(page, vma->vm_page_prot);
>>> -	entry = pte_sw_mkyoung(entry);
>>>  	if (write)
>>>  		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
>>>  	/* copy-on-write page */
>>>
> 
> I search for pte_sw_mkyoung/pte_{clear,mk,}_savewrite, none of which is
> used, do I really need to remove pte_sw_mkyoung in this patch just for
> *not used* ?
> 
macro pte_sw_mkyoung is added by me previously, and it is defined as empty excepts mips
system. If it is not used any more on mips sytem, I suggest that it should be removed here.

regards
bibo,mao


  reply	other threads:[~2020-09-07 13:11 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-04  8:49 [PATCH] MIPS: make userspace mapping young by default Huang Pei
2020-09-07  8:50 ` maobibo
2020-09-07 10:35   ` Huang Pei
2020-09-07 13:10     ` maobibo [this message]
  -- strict thread matches above, loose matches on Subject: below --
2021-02-04  1:39 Huang Pei
2021-02-04  3:29 ` Nicholas Piggin
2021-02-04  4:46   ` 黄沛
2021-02-04 10:34   ` Thomas Bogendoerfer
2021-02-04 11:27     ` Nicholas Piggin
2021-02-04 15:22 ` Thomas Bogendoerfer
2021-02-05 23:41   ` Andrew Morton
2021-02-08 17:44     ` Christophe Leroy
2021-02-08 19:48       ` Andrew Morton
2020-09-19  7:39 Huang Pei
2020-07-26  8:32 [PATCH v2 1/2] MIPS: Set page access bit with pgprot on platforms with RIXI Thomas Bogendoerfer
2020-08-25  3:20 ` [PATCH v2 1/2] MIPS: Set page access bit with pgprot on Huang Pei
2020-08-25  3:20   ` [PATCH] MIPS: make userspace mapping young by default Huang Pei

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