[v3] ARC: mm: remove __ARCH_USE_5LEVEL_HACK
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Message ID 20191009185731.25814-1-vgupta@synopsys.com
State New
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Series
  • [v3] ARC: mm: remove __ARCH_USE_5LEVEL_HACK
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Commit Message

Vineet Gupta Oct. 9, 2019, 6:57 p.m. UTC
Add the intermediate p4d accessors to make it 5 level compliant.

This is a non-functional change anyways since ARC has software page walker
with 2 lookup levels (pgd -> pte)

There is slight code bloat due to pulling in needless p*d_free_tlb()
macros which needs to be addressed seperately.

| bloat-o-meter2 vmlinux-with-5LEVEL_HACK vmlinux-patched
| add/remove: 0/0 grow/shrink: 2/0 up/down: 128/0 (128)
| function                                     old     new   delta
| free_pgd_range                               546     656    +110
| p4d_clear_bad                                  2      20     +18
| Total: Before=4137148, After=4137276, chg 0.000000%

Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
v3 <- v2
  - fix highmem build error

v2 <- v1
 - fix highmem code
---
 arch/arc/include/asm/pgtable.h |  1 -
 arch/arc/mm/fault.c            | 10 ++++++++--
 arch/arc/mm/highmem.c          |  4 +++-
 3 files changed, 11 insertions(+), 4 deletions(-)

Comments

Kirill A. Shutemov Oct. 10, 2019, 8:28 a.m. UTC | #1
On Wed, Oct 09, 2019 at 06:57:31PM +0000, Vineet Gupta wrote:
> Add the intermediate p4d accessors to make it 5 level compliant.
> 
> This is a non-functional change anyways since ARC has software page walker
> with 2 lookup levels (pgd -> pte)
> 
> There is slight code bloat due to pulling in needless p*d_free_tlb()
> macros which needs to be addressed seperately.
> 
> | bloat-o-meter2 vmlinux-with-5LEVEL_HACK vmlinux-patched
> | add/remove: 0/0 grow/shrink: 2/0 up/down: 128/0 (128)
> | function                                     old     new   delta
> | free_pgd_range                               546     656    +110
> | p4d_clear_bad                                  2      20     +18
> | Total: Before=4137148, After=4137276, chg 0.000000%
> 
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Mike Rapoport Oct. 22, 2019, 3:23 p.m. UTC | #2
On Wed, Oct 09, 2019 at 11:57:31AM -0700, Vineet Gupta wrote:
> Add the intermediate p4d accessors to make it 5 level compliant.
> 
> This is a non-functional change anyways since ARC has software page walker
> with 2 lookup levels (pgd -> pte)
> 
> There is slight code bloat due to pulling in needless p*d_free_tlb()
> macros which needs to be addressed seperately.
> 
> | bloat-o-meter2 vmlinux-with-5LEVEL_HACK vmlinux-patched
> | add/remove: 0/0 grow/shrink: 2/0 up/down: 128/0 (128)
> | function                                     old     new   delta
> | free_pgd_range                               546     656    +110
> | p4d_clear_bad                                  2      20     +18
> | Total: Before=4137148, After=4137276, chg 0.000000%
> 
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Acked-by: Mike Rapoport <rppt@linux.ibm.com>

> ---
> v3 <- v2
>   - fix highmem build error
> 
> v2 <- v1
>  - fix highmem code
> ---
>  arch/arc/include/asm/pgtable.h |  1 -
>  arch/arc/mm/fault.c            | 10 ++++++++--
>  arch/arc/mm/highmem.c          |  4 +++-
>  3 files changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
> index 976b5931372e..902d45428cea 100644
> --- a/arch/arc/include/asm/pgtable.h
> +++ b/arch/arc/include/asm/pgtable.h
> @@ -33,7 +33,6 @@
>  #define _ASM_ARC_PGTABLE_H
>  
>  #include <linux/bits.h>
> -#define __ARCH_USE_5LEVEL_HACK
>  #include <asm-generic/pgtable-nopmd.h>
>  #include <asm/page.h>
>  #include <asm/mmu.h>	/* to propagate CONFIG_ARC_MMU_VER <n> */
> diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
> index 3861543b66a0..fb86bc3e9b35 100644
> --- a/arch/arc/mm/fault.c
> +++ b/arch/arc/mm/fault.c
> @@ -30,6 +30,7 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address)
>  	 * with the 'reference' page table.
>  	 */
>  	pgd_t *pgd, *pgd_k;
> +	p4d_t *p4d, *p4d_k;
>  	pud_t *pud, *pud_k;
>  	pmd_t *pmd, *pmd_k;
>  
> @@ -39,8 +40,13 @@ noinline static int handle_kernel_vaddr_fault(unsigned long address)
>  	if (!pgd_present(*pgd_k))
>  		goto bad_area;
>  
> -	pud = pud_offset(pgd, address);
> -	pud_k = pud_offset(pgd_k, address);
> +	p4d = p4d_offset(pgd, address);
> +	p4d_k = p4d_offset(pgd_k, address);
> +	if (!p4d_present(*p4d_k))
> +		goto bad_area;
> +
> +	pud = pud_offset(p4d, address);
> +	pud_k = pud_offset(p4d_k, address);
>  	if (!pud_present(*pud_k))
>  		goto bad_area;
>  
> diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
> index a4856bfaedf3..fc8849e4f72e 100644
> --- a/arch/arc/mm/highmem.c
> +++ b/arch/arc/mm/highmem.c
> @@ -111,12 +111,14 @@ EXPORT_SYMBOL(__kunmap_atomic);
>  static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
>  {
>  	pgd_t *pgd_k;
> +	p4d_t *p4d_k;
>  	pud_t *pud_k;
>  	pmd_t *pmd_k;
>  	pte_t *pte_k;
>  
>  	pgd_k = pgd_offset_k(kvaddr);
> -	pud_k = pud_offset(pgd_k, kvaddr);
> +	p4d_k = p4d_offset(pgd_k, kvaddr);
> +	pud_k = pud_offset(p4d_k, kvaddr);
>  	pmd_k = pmd_offset(pud_k, kvaddr);
>  
>  	pte_k = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
> -- 
> 2.20.1
> 
>

Patch
diff mbox series

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 976b5931372e..902d45428cea 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -33,7 +33,6 @@ 
 #define _ASM_ARC_PGTABLE_H
 
 #include <linux/bits.h>
-#define __ARCH_USE_5LEVEL_HACK
 #include <asm-generic/pgtable-nopmd.h>
 #include <asm/page.h>
 #include <asm/mmu.h>	/* to propagate CONFIG_ARC_MMU_VER <n> */
diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index 3861543b66a0..fb86bc3e9b35 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -30,6 +30,7 @@  noinline static int handle_kernel_vaddr_fault(unsigned long address)
 	 * with the 'reference' page table.
 	 */
 	pgd_t *pgd, *pgd_k;
+	p4d_t *p4d, *p4d_k;
 	pud_t *pud, *pud_k;
 	pmd_t *pmd, *pmd_k;
 
@@ -39,8 +40,13 @@  noinline static int handle_kernel_vaddr_fault(unsigned long address)
 	if (!pgd_present(*pgd_k))
 		goto bad_area;
 
-	pud = pud_offset(pgd, address);
-	pud_k = pud_offset(pgd_k, address);
+	p4d = p4d_offset(pgd, address);
+	p4d_k = p4d_offset(pgd_k, address);
+	if (!p4d_present(*p4d_k))
+		goto bad_area;
+
+	pud = pud_offset(p4d, address);
+	pud_k = pud_offset(p4d_k, address);
 	if (!pud_present(*pud_k))
 		goto bad_area;
 
diff --git a/arch/arc/mm/highmem.c b/arch/arc/mm/highmem.c
index a4856bfaedf3..fc8849e4f72e 100644
--- a/arch/arc/mm/highmem.c
+++ b/arch/arc/mm/highmem.c
@@ -111,12 +111,14 @@  EXPORT_SYMBOL(__kunmap_atomic);
 static noinline pte_t * __init alloc_kmap_pgtable(unsigned long kvaddr)
 {
 	pgd_t *pgd_k;
+	p4d_t *p4d_k;
 	pud_t *pud_k;
 	pmd_t *pmd_k;
 	pte_t *pte_k;
 
 	pgd_k = pgd_offset_k(kvaddr);
-	pud_k = pud_offset(pgd_k, kvaddr);
+	p4d_k = p4d_offset(pgd_k, kvaddr);
+	pud_k = pud_offset(p4d_k, kvaddr);
 	pmd_k = pmd_offset(pud_k, kvaddr);
 
 	pte_k = (pte_t *)memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);