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* [PATCH v4] riscv: mm: Remove the copy operation of pmd
@ 2022-04-01  2:43 ` Chuanhua Han
  0 siblings, 0 replies; 4+ messages in thread
From: Chuanhua Han @ 2022-04-01  2:43 UTC (permalink / raw)
  To: paul.walmsley, palmer, aou
  Cc: alexandre.ghiti, jszhang, mhiramat, akpm, zhengqi.arch, ebiederm,
	liushixin2, linux-riscv, linux-kernel, Chuanhua Han

Since all processes share the kernel address space,
we only need to copy pgd in case of a vmalloc page
fault exception, the other levels of page tables are
shared, so the operation of copying pmd is unnecessary.

Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
---
Changes in v4:
  -Modify incorrect author name.

Changes in v3:
  -Change the real name of signed-off-by.

Changes in v2:
  -Delete incorrect default signatures.


 arch/riscv/mm/fault.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 4e9efbe46d5f..40694f0cab9e 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code
 static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
 {
 	pgd_t *pgd, *pgd_k;
-	pud_t *pud, *pud_k;
-	p4d_t *p4d, *p4d_k;
-	pmd_t *pmd, *pmd_k;
+	pud_t *pud_k;
+	p4d_t *p4d_k;
+	pmd_t *pmd_k;
 	pte_t *pte_k;
 	int index;
 	unsigned long pfn;
@@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
 	}
 	set_pgd(pgd, *pgd_k);
 
-	p4d = p4d_offset(pgd, addr);
 	p4d_k = p4d_offset(pgd_k, addr);
 	if (!p4d_present(*p4d_k)) {
 		no_context(regs, addr);
 		return;
 	}
 
-	pud = pud_offset(p4d, addr);
 	pud_k = pud_offset(p4d_k, addr);
 	if (!pud_present(*pud_k)) {
 		no_context(regs, addr);
@@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
 	 * Since the vmalloc area is global, it is unnecessary
 	 * to copy individual PTEs
 	 */
-	pmd = pmd_offset(pud, addr);
 	pmd_k = pmd_offset(pud_k, addr);
 	if (!pmd_present(*pmd_k)) {
 		no_context(regs, addr);
 		return;
 	}
-	set_pmd(pmd, *pmd_k);
 
 	/*
 	 * Make sure the actual PTE exists as well to
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH v4] riscv: mm: Remove the copy operation of pmd
@ 2022-04-01  2:43 ` Chuanhua Han
  0 siblings, 0 replies; 4+ messages in thread
From: Chuanhua Han @ 2022-04-01  2:43 UTC (permalink / raw)
  To: paul.walmsley, palmer, aou
  Cc: alexandre.ghiti, jszhang, mhiramat, akpm, zhengqi.arch, ebiederm,
	liushixin2, linux-riscv, linux-kernel, Chuanhua Han

Since all processes share the kernel address space,
we only need to copy pgd in case of a vmalloc page
fault exception, the other levels of page tables are
shared, so the operation of copying pmd is unnecessary.

Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
---
Changes in v4:
  -Modify incorrect author name.

Changes in v3:
  -Change the real name of signed-off-by.

Changes in v2:
  -Delete incorrect default signatures.


 arch/riscv/mm/fault.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 4e9efbe46d5f..40694f0cab9e 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code
 static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
 {
 	pgd_t *pgd, *pgd_k;
-	pud_t *pud, *pud_k;
-	p4d_t *p4d, *p4d_k;
-	pmd_t *pmd, *pmd_k;
+	pud_t *pud_k;
+	p4d_t *p4d_k;
+	pmd_t *pmd_k;
 	pte_t *pte_k;
 	int index;
 	unsigned long pfn;
@@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
 	}
 	set_pgd(pgd, *pgd_k);
 
-	p4d = p4d_offset(pgd, addr);
 	p4d_k = p4d_offset(pgd_k, addr);
 	if (!p4d_present(*p4d_k)) {
 		no_context(regs, addr);
 		return;
 	}
 
-	pud = pud_offset(p4d, addr);
 	pud_k = pud_offset(p4d_k, addr);
 	if (!pud_present(*pud_k)) {
 		no_context(regs, addr);
@@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
 	 * Since the vmalloc area is global, it is unnecessary
 	 * to copy individual PTEs
 	 */
-	pmd = pmd_offset(pud, addr);
 	pmd_k = pmd_offset(pud_k, addr);
 	if (!pmd_present(*pmd_k)) {
 		no_context(regs, addr);
 		return;
 	}
-	set_pmd(pmd, *pmd_k);
 
 	/*
 	 * Make sure the actual PTE exists as well to
-- 
2.25.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: [PATCH v4] riscv: mm: Remove the copy operation of pmd
  2022-04-01  2:43 ` Chuanhua Han
@ 2022-04-21 17:05   ` Palmer Dabbelt
  -1 siblings, 0 replies; 4+ messages in thread
From: Palmer Dabbelt @ 2022-04-21 17:05 UTC (permalink / raw)
  To: hanchuanhua
  Cc: Paul Walmsley, aou, alexandre.ghiti, jszhang, mhiramat, akpm,
	zhengqi.arch, ebiederm, liushixin2, linux-riscv, linux-kernel,
	hanchuanhua

On Thu, 31 Mar 2022 19:43:20 PDT (-0700), hanchuanhua@oppo.com wrote:
> Since all processes share the kernel address space,
> we only need to copy pgd in case of a vmalloc page
> fault exception, the other levels of page tables are
> shared, so the operation of copying pmd is unnecessary.
>
> Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
> ---
> Changes in v4:
>   -Modify incorrect author name.
>
> Changes in v3:
>   -Change the real name of signed-off-by.
>
> Changes in v2:
>   -Delete incorrect default signatures.
>
>
>  arch/riscv/mm/fault.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index 4e9efbe46d5f..40694f0cab9e 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code
>  static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
>  {
>  	pgd_t *pgd, *pgd_k;
> -	pud_t *pud, *pud_k;
> -	p4d_t *p4d, *p4d_k;
> -	pmd_t *pmd, *pmd_k;
> +	pud_t *pud_k;
> +	p4d_t *p4d_k;
> +	pmd_t *pmd_k;
>  	pte_t *pte_k;
>  	int index;
>  	unsigned long pfn;
> @@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
>  	}
>  	set_pgd(pgd, *pgd_k);
>
> -	p4d = p4d_offset(pgd, addr);
>  	p4d_k = p4d_offset(pgd_k, addr);
>  	if (!p4d_present(*p4d_k)) {
>  		no_context(regs, addr);
>  		return;
>  	}
>
> -	pud = pud_offset(p4d, addr);
>  	pud_k = pud_offset(p4d_k, addr);
>  	if (!pud_present(*pud_k)) {
>  		no_context(regs, addr);
> @@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
>  	 * Since the vmalloc area is global, it is unnecessary
>  	 * to copy individual PTEs
>  	 */
> -	pmd = pmd_offset(pud, addr);
>  	pmd_k = pmd_offset(pud_k, addr);
>  	if (!pmd_present(*pmd_k)) {
>  		no_context(regs, addr);
>  		return;
>  	}
> -	set_pmd(pmd, *pmd_k);
>
>  	/*
>  	 * Make sure the actual PTE exists as well to

Thanks, this is on for-next (it was last night, but looks like I forgot 
to send the email).

^ permalink raw reply	[flat|nested] 4+ messages in thread
* Re: [PATCH v4] riscv: mm: Remove the copy operation of pmd
@ 2022-04-21 17:05   ` Palmer Dabbelt
  0 siblings, 0 replies; 4+ messages in thread
From: Palmer Dabbelt @ 2022-04-21 17:05 UTC (permalink / raw)
  To: hanchuanhua
  Cc: Paul Walmsley, aou, alexandre.ghiti, jszhang, mhiramat, akpm,
	zhengqi.arch, ebiederm, liushixin2, linux-riscv, linux-kernel,
	hanchuanhua

On Thu, 31 Mar 2022 19:43:20 PDT (-0700), hanchuanhua@oppo.com wrote:
> Since all processes share the kernel address space,
> we only need to copy pgd in case of a vmalloc page
> fault exception, the other levels of page tables are
> shared, so the operation of copying pmd is unnecessary.
>
> Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
> ---
> Changes in v4:
>   -Modify incorrect author name.
>
> Changes in v3:
>   -Change the real name of signed-off-by.
>
> Changes in v2:
>   -Delete incorrect default signatures.
>
>
>  arch/riscv/mm/fault.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
> index 4e9efbe46d5f..40694f0cab9e 100644
> --- a/arch/riscv/mm/fault.c
> +++ b/arch/riscv/mm/fault.c
> @@ -102,9 +102,9 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code
>  static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
>  {
>  	pgd_t *pgd, *pgd_k;
> -	pud_t *pud, *pud_k;
> -	p4d_t *p4d, *p4d_k;
> -	pmd_t *pmd, *pmd_k;
> +	pud_t *pud_k;
> +	p4d_t *p4d_k;
> +	pmd_t *pmd_k;
>  	pte_t *pte_k;
>  	int index;
>  	unsigned long pfn;
> @@ -132,14 +132,12 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
>  	}
>  	set_pgd(pgd, *pgd_k);
>
> -	p4d = p4d_offset(pgd, addr);
>  	p4d_k = p4d_offset(pgd_k, addr);
>  	if (!p4d_present(*p4d_k)) {
>  		no_context(regs, addr);
>  		return;
>  	}
>
> -	pud = pud_offset(p4d, addr);
>  	pud_k = pud_offset(p4d_k, addr);
>  	if (!pud_present(*pud_k)) {
>  		no_context(regs, addr);
> @@ -150,13 +148,11 @@ static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long a
>  	 * Since the vmalloc area is global, it is unnecessary
>  	 * to copy individual PTEs
>  	 */
> -	pmd = pmd_offset(pud, addr);
>  	pmd_k = pmd_offset(pud_k, addr);
>  	if (!pmd_present(*pmd_k)) {
>  		no_context(regs, addr);
>  		return;
>  	}
> -	set_pmd(pmd, *pmd_k);
>
>  	/*
>  	 * Make sure the actual PTE exists as well to

Thanks, this is on for-next (it was last night, but looks like I forgot 
to send the email).

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-04-21 17:05 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-01  2:43 [PATCH v4] riscv: mm: Remove the copy operation of pmd Chuanhua Han
2022-04-01  2:43 ` Chuanhua Han
2022-04-21 17:05 ` Palmer Dabbelt
2022-04-21 17:05   ` Palmer Dabbelt

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