* [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform
@ 2020-06-05 9:11 Bibo Mao
2020-06-05 9:11 ` [PATCH 2/2] MIPS: Add writable-applies-readable policy with pgrot Bibo Mao
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Bibo Mao @ 2020-06-05 9:11 UTC (permalink / raw)
To: Thomas Bogendoerfer, Andrew Morton, Paul Burton, Jiaxun Yang
Cc: linux-mips, linux-kernel, linux-arch, linux-mm
On MIPS system which has rixi hardware bit, page access bit is not
set in pgrot. For memory reading, there will be one page fault to
allocate physical page; however valid bit is not set, there will
be the second fast tlb-miss fault handling to set valid/access bit.
This patch set page access/valid bit with pgrot if there is reading
access privilege. It will reduce one tlb-miss handling for memory
reading access.
The valid/access bit will be cleared in order to track memory
accessing activity. If the page is accessed, tlb-miss fast handling
will set valid/access bit, pte_sw_mkyoung is not necessary in slow
page fault path. This patch removes pte_sw_mkyoung function which
is defined as empty function except MIPS system.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
arch/mips/include/asm/pgtable.h | 11 +++++++++--
arch/mips/mm/cache.c | 34 +++++++++++++++++-----------------
include/asm-generic/pgtable.h | 16 ----------------
mm/memory.c | 3 ---
4 files changed, 26 insertions(+), 38 deletions(-)
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 85b39c9..e2452ab 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -25,6 +25,15 @@
struct mm_struct;
struct vm_area_struct;
+#define __PP _PAGE_PRESENT
+#define __NX _PAGE_NO_EXEC
+#define __NR _PAGE_NO_READ
+#define ___W _PAGE_WRITE
+#define ___A _PAGE_ACCESSED
+#define ___R (_PAGE_SILENT_READ | _PAGE_ACCESSED)
+#define __PC _page_cachable_default
+
+
#define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \
_page_cachable_default)
#define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \
@@ -414,8 +423,6 @@ 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 ad6df1c..f814e43 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -158,23 +158,23 @@ void __update_cache(unsigned long address, pte_t pte)
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[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[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[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[0] = __pgprot(__PC | __PP | __NX | __NR);
+ protection_map[1] = __pgprot(__PC | __PP | __NX | ___R);
+ protection_map[2] = __pgprot(__PC | __PP | __NX | __NR);
+ protection_map[3] = __pgprot(__PC | __PP | __NX | ___R);
+ protection_map[4] = __pgprot(__PC | __PP | ___R);
+ protection_map[5] = __pgprot(__PC | __PP | ___R);
+ protection_map[6] = __pgprot(__PC | __PP | ___R);
+ protection_map[7] = __pgprot(__PC | __PP | ___R);
+
+ protection_map[8] = __pgprot(__PC | __PP | __NX | __NR);
+ protection_map[9] = __pgprot(__PC | __PP | __NX | ___R);
+ protection_map[10] = __pgprot(__PC | __PP | __NX | ___W | __NR);
+ protection_map[11] = __pgprot(__PC | __PP | __NX | ___W | ___R);
+ protection_map[12] = __pgprot(__PC | __PP | ___R);
+ protection_map[13] = __pgprot(__PC | __PP | ___R);
+ protection_map[14] = __pgprot(__PC | __PP | ___W | ___R);
+ protection_map[15] = __pgprot(__PC | __PP | ___W | ___R);
} else {
protection_map[0] = PAGE_NONE;
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index b5278ec..fa5c73f 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -244,22 +244,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres
}
#endif
-/*
- * On some architectures hardware does not set page access bit when accessing
- * memory page, it is responsibilty of software setting this bit. It brings
- * out extra page fault penalty to track page access bit. For optimization page
- * access bit can be set during all page fault flow on these arches.
- * To be differentiate with macro pte_mkyoung, this macro is used on platforms
- * where software maintains page access bit.
- */
-#ifndef pte_sw_mkyoung
-static inline pte_t pte_sw_mkyoung(pte_t pte)
-{
- return pte;
-}
-#define pte_sw_mkyoung pte_sw_mkyoung
-#endif
-
#ifndef pte_savedwrite
#define pte_savedwrite pte_write
#endif
diff --git a/mm/memory.c b/mm/memory.c
index c7c8960..8bb31c4 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2704,7 +2704,6 @@ 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
@@ -3379,7 +3378,6 @@ 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));
@@ -3662,7 +3660,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
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 */
--
1.8.3.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] MIPS: Add writable-applies-readable policy with pgrot
2020-06-05 9:11 [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform Bibo Mao
@ 2020-06-05 9:11 ` Bibo Mao
2020-06-05 9:39 ` [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform Jiaxun Yang
2020-06-06 1:08 ` Andrew Morton
2 siblings, 0 replies; 5+ messages in thread
From: Bibo Mao @ 2020-06-05 9:11 UTC (permalink / raw)
To: Thomas Bogendoerfer, Andrew Morton, Paul Burton, Jiaxun Yang
Cc: linux-mips, linux-kernel, linux-arch, linux-mm
On Linux system, writable applies readable privilege in most
architectures, this patch adds this policy on MIPS platform
where hardware rixi is supported.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
arch/mips/mm/cache.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c
index f814e43..dae0617 100644
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -160,7 +160,7 @@ static inline void setup_protection_map(void)
if (cpu_has_rixi) {
protection_map[0] = __pgprot(__PC | __PP | __NX | __NR);
protection_map[1] = __pgprot(__PC | __PP | __NX | ___R);
- protection_map[2] = __pgprot(__PC | __PP | __NX | __NR);
+ protection_map[2] = __pgprot(__PC | __PP | __NX | ___R);
protection_map[3] = __pgprot(__PC | __PP | __NX | ___R);
protection_map[4] = __pgprot(__PC | __PP | ___R);
protection_map[5] = __pgprot(__PC | __PP | ___R);
@@ -169,7 +169,7 @@ static inline void setup_protection_map(void)
protection_map[8] = __pgprot(__PC | __PP | __NX | __NR);
protection_map[9] = __pgprot(__PC | __PP | __NX | ___R);
- protection_map[10] = __pgprot(__PC | __PP | __NX | ___W | __NR);
+ protection_map[10] = __pgprot(__PC | __PP | __NX | ___W | ___R);
protection_map[11] = __pgprot(__PC | __PP | __NX | ___W | ___R);
protection_map[12] = __pgprot(__PC | __PP | ___R);
protection_map[13] = __pgprot(__PC | __PP | ___R);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform
2020-06-05 9:11 [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform Bibo Mao
2020-06-05 9:11 ` [PATCH 2/2] MIPS: Add writable-applies-readable policy with pgrot Bibo Mao
@ 2020-06-05 9:39 ` Jiaxun Yang
2020-06-05 9:51 ` maobibo
2020-06-06 1:08 ` Andrew Morton
2 siblings, 1 reply; 5+ messages in thread
From: Jiaxun Yang @ 2020-06-05 9:39 UTC (permalink / raw)
To: Bibo Mao
Cc: Thomas Bogendoerfer, Andrew Morton, Paul Burton, linux-mips,
linux-kernel, linux-arch, linux-mm
On Fri, 5 Jun 2020 17:11:05 +0800
Bibo Mao <maobibo@loongson.cn> wrote:
> On MIPS system which has rixi hardware bit, page access bit is not
> set in pgrot. For memory reading, there will be one page fault to
> allocate physical page; however valid bit is not set, there will
> be the second fast tlb-miss fault handling to set valid/access bit.
>
> This patch set page access/valid bit with pgrot if there is reading
> access privilege. It will reduce one tlb-miss handling for memory
> reading access.
>
> The valid/access bit will be cleared in order to track memory
> accessing activity. If the page is accessed, tlb-miss fast handling
> will set valid/access bit, pte_sw_mkyoung is not necessary in slow
> page fault path. This patch removes pte_sw_mkyoung function which
> is defined as empty function except MIPS system.
>
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
Thanks for tracking it down.
Could you please make the patch tittle more clear?
"Some" looks confuse to me, "systems with RIXI" would be better.
- Jiaxun
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform
2020-06-05 9:39 ` [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform Jiaxun Yang
@ 2020-06-05 9:51 ` maobibo
0 siblings, 0 replies; 5+ messages in thread
From: maobibo @ 2020-06-05 9:51 UTC (permalink / raw)
To: Jiaxun Yang
Cc: Thomas Bogendoerfer, Andrew Morton, Paul Burton, linux-mips,
linux-kernel, linux-arch, linux-mm
On 06/05/2020 05:39 PM, Jiaxun Yang wrote:
> On Fri, 5 Jun 2020 17:11:05 +0800
> Bibo Mao <maobibo@loongson.cn> wrote:
>
>> On MIPS system which has rixi hardware bit, page access bit is not
>> set in pgrot. For memory reading, there will be one page fault to
>> allocate physical page; however valid bit is not set, there will
>> be the second fast tlb-miss fault handling to set valid/access bit.
>>
>> This patch set page access/valid bit with pgrot if there is reading
>> access privilege. It will reduce one tlb-miss handling for memory
>> reading access.
>>
>> The valid/access bit will be cleared in order to track memory
>> accessing activity. If the page is accessed, tlb-miss fast handling
>> will set valid/access bit, pte_sw_mkyoung is not necessary in slow
>> page fault path. This patch removes pte_sw_mkyoung function which
>> is defined as empty function except MIPS system.
>>
>> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
>> ---
>
> Thanks for tracking it down.
>
> Could you please make the patch tittle more clear?
> "Some" looks confuse to me, "systems with RIXI" would be better.
Sure, will add it.
>
> - Jiaxun
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform
2020-06-05 9:11 [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform Bibo Mao
2020-06-05 9:11 ` [PATCH 2/2] MIPS: Add writable-applies-readable policy with pgrot Bibo Mao
2020-06-05 9:39 ` [PATCH 1/2] MIPS: set page access bit with pgprot on some MIPS platform Jiaxun Yang
@ 2020-06-06 1:08 ` Andrew Morton
2 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2020-06-06 1:08 UTC (permalink / raw)
To: Bibo Mao
Cc: Thomas Bogendoerfer, Paul Burton, Jiaxun Yang, linux-mips,
linux-kernel, linux-arch, linux-mm
On Fri, 5 Jun 2020 17:11:05 +0800 Bibo Mao <maobibo@loongson.cn> wrote:
> On MIPS system which has rixi hardware bit, page access bit is not
> set in pgrot. For memory reading, there will be one page fault to
> allocate physical page; however valid bit is not set, there will
> be the second fast tlb-miss fault handling to set valid/access bit.
>
> This patch set page access/valid bit with pgrot if there is reading
> access privilege. It will reduce one tlb-miss handling for memory
> reading access.
>
> The valid/access bit will be cleared in order to track memory
> accessing activity. If the page is accessed, tlb-miss fast handling
> will set valid/access bit, pte_sw_mkyoung is not necessary in slow
> page fault path. This patch removes pte_sw_mkyoung function which
> is defined as empty function except MIPS system.
>
> ...
>
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2704,7 +2704,6 @@ 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
> @@ -3379,7 +3378,6 @@ 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));
>
> @@ -3662,7 +3660,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
>
> 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 */
Only affects mips, so cheerily
Acked-by: Andrew Morton <akpm@linux-foundation.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
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