2014-04-29 04:59:26

by Jungseok Lee

[permalink] [raw]
Subject: [PATCH v4 2/7] arm64: Decouple page size from level of translation tables

This patch separates page size from level of translation tables in
configuration. It facilitates introduction of different options,
such as 4KB + 4 levels, 16KB + 4 levels and 64KB + 3 levels, easily.

Cc: Catalin Marinas <[email protected]>
Cc: Steve Capper <[email protected]>
Signed-off-by: Jungseok Lee <[email protected]>
Reviewed-by: Sungjinn Chung <[email protected]>
---
arch/arm64/Kconfig | 36 +++++++++++++++++++++++++++++++-
arch/arm64/include/asm/page.h | 2 +-
arch/arm64/include/asm/pgalloc.h | 4 ++--
arch/arm64/include/asm/pgtable-hwdef.h | 2 +-
arch/arm64/include/asm/pgtable.h | 8 +++----
arch/arm64/include/asm/tlb.h | 2 +-
6 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index e759af5..c7f5d65 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -144,14 +144,48 @@ endmenu

menu "Kernel Features"

+choice
+ prompt "Page size"
+ default ARM64_4K_PAGES
+ help
+ Allows page size.
+
+config ARM64_4K_PAGES
+ bool "4KB"
+ help
+ This feature enables 4KB pages support.
+
config ARM64_64K_PAGES
- bool "Enable 64KB pages support"
+ bool "64KB"
help
This feature enables 64KB pages support (4KB by default)
allowing only two levels of page tables and faster TLB
look-up. AArch32 emulation is not available when this feature
is enabled.

+endchoice
+
+choice
+ prompt "Level of translation tables"
+ default ARM64_3_LEVELS if ARM64_4K_PAGES
+ default ARM64_2_LEVELS if ARM64_64K_PAGES
+ help
+ Allows level of translation tables.
+
+config ARM64_2_LEVELS
+ bool "2 level"
+ depends on ARM64_64K_PAGES
+ help
+ This feature enables 2 levels of translation tables.
+
+config ARM64_3_LEVELS
+ bool "3 level"
+ depends on ARM64_4K_PAGES
+ help
+ This feature enables 3 levels of translation tables.
+
+endchoice
+
config CPU_BIG_ENDIAN
bool "Build big-endian kernel"
help
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 46bf666..268e53d 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -33,7 +33,7 @@

#ifndef __ASSEMBLY__

-#ifdef CONFIG_ARM64_64K_PAGES
+#ifdef CONFIG_ARM64_2_LEVELS
#include <asm/pgtable-2level-types.h>
#else
#include <asm/pgtable-3level-types.h>
diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 9bea6e7..4829837 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -26,7 +26,7 @@

#define check_pgt_cache() do { } while (0)

-#ifndef CONFIG_ARM64_64K_PAGES
+#ifndef CONFIG_ARM64_2_LEVELS

static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
{
@@ -44,7 +44,7 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
}

-#endif /* CONFIG_ARM64_64K_PAGES */
+#endif /* CONFIG_ARM64_2_LEVELS */

extern pgd_t *pgd_alloc(struct mm_struct *mm);
extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index 5fc8a66..9cd86c6 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -16,7 +16,7 @@
#ifndef __ASM_PGTABLE_HWDEF_H
#define __ASM_PGTABLE_HWDEF_H

-#ifdef CONFIG_ARM64_64K_PAGES
+#ifdef CONFIG_ARM64_2_LEVELS
#include <asm/pgtable-2level-hwdef.h>
#else
#include <asm/pgtable-3level-hwdef.h>
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 90c811f..a64ce5e 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -47,7 +47,7 @@ extern void __pmd_error(const char *file, int line, unsigned long val);
extern void __pgd_error(const char *file, int line, unsigned long val);

#define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte))
-#ifndef CONFIG_ARM64_64K_PAGES
+#ifndef CONFIG_ARM64_2_LEVELS
#define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
#endif
#define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
@@ -320,7 +320,7 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)
*/
#define mk_pte(page,prot) pfn_pte(page_to_pfn(page),prot)

-#ifndef CONFIG_ARM64_64K_PAGES
+#ifndef CONFIG_ARM64_2_LEVELS

#define pud_none(pud) (!pud_val(pud))
#define pud_bad(pud) (!(pud_val(pud) & 2))
@@ -342,7 +342,7 @@ static inline pmd_t *pud_page_vaddr(pud_t pud)
return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
}

-#endif /* CONFIG_ARM64_64K_PAGES */
+#endif /* CONFIG_ARM64_2_LEVELS */

/* to find an entry in a page-table-directory */
#define pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
@@ -353,7 +353,7 @@ static inline pmd_t *pud_page_vaddr(pud_t pud)
#define pgd_offset_k(addr) pgd_offset(&init_mm, addr)

/* Find an entry in the second-level page table.. */
-#ifndef CONFIG_ARM64_64K_PAGES
+#ifndef CONFIG_ARM64_2_LEVELS
#define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
{
diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index 80e2c08..bc19101 100644
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -91,7 +91,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
tlb_remove_page(tlb, pte);
}

-#ifndef CONFIG_ARM64_64K_PAGES
+#ifndef CONFIG_ARM64_2_LEVELS
static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
unsigned long addr)
{
--
1.7.10.4


2014-04-29 14:41:34

by Catalin Marinas

[permalink] [raw]
Subject: Re: [PATCH v4 2/7] arm64: Decouple page size from level of translation tables

Jungseok,

On Tue, Apr 29, 2014 at 05:59:20AM +0100, Jungseok Lee wrote:
> +choice
> + prompt "Level of translation tables"
> + default ARM64_3_LEVELS if ARM64_4K_PAGES
> + default ARM64_2_LEVELS if ARM64_64K_PAGES
> + help
> + Allows level of translation tables.
> +
> +config ARM64_2_LEVELS
> + bool "2 level"
> + depends on ARM64_64K_PAGES
> + help
> + This feature enables 2 levels of translation tables.
> +
> +config ARM64_3_LEVELS
> + bool "3 level"
> + depends on ARM64_4K_PAGES
> + help
> + This feature enables 3 levels of translation tables.
> +
> +endchoice

As I mentioned previously
(http://www.spinics.net/linux/lists/arm-kernel/msg319552.html), just
expose options for the VA space bits rather than the number of levels.
You can still keep the number of levels config options but not visible
in menuconfig (though I think you could also hide them in some header
and avoid config altogether). The VA bits config options can be:

VA_BITS_39 if 4K (3 levels)
VA_BITS_42 if 64K (2 levels)
VA_BITS_47 if 16K (3 levels)
VA_BITS_48 if 4K || 16K || 64K (4/4/3 levels depending on page size)

That's more meaningful to people configuring the kernel.

--
Catalin

2014-04-30 02:44:22

by Jungseok Lee

[permalink] [raw]
Subject: Re: [PATCH v4 2/7] arm64: Decouple page size from level of translation tables

On Tuesday, April 29, 2014 11:41 PM, Catalin Marinas wrote:
> Jungseok,

Hi, Catalin

> On Tue, Apr 29, 2014 at 05:59:20AM +0100, Jungseok Lee wrote:
> > +choice
> > + prompt "Level of translation tables"
> > + default ARM64_3_LEVELS if ARM64_4K_PAGES
> > + default ARM64_2_LEVELS if ARM64_64K_PAGES
> > + help
> > + Allows level of translation tables.
> > +
> > +config ARM64_2_LEVELS
> > + bool "2 level"
> > + depends on ARM64_64K_PAGES
> > + help
> > + This feature enables 2 levels of translation tables.
> > +
> > +config ARM64_3_LEVELS
> > + bool "3 level"
> > + depends on ARM64_4K_PAGES
> > + help
> > + This feature enables 3 levels of translation tables.
> > +
> > +endchoice
>
> As I mentioned previously
> (http://www.spinics.net/linux/lists/arm-kernel/msg319552.html), just expose options for the VA space
> bits rather than the number of levels.
> You can still keep the number of levels config options but not visible in menuconfig (though I think
> you could also hide them in some header and avoid config altogether). The VA bits config options can
> be:
>
> VA_BITS_39 if 4K (3 levels)
> VA_BITS_42 if 64K (2 levels)
> VA_BITS_47 if 16K (3 levels)
> VA_BITS_48 if 4K || 16K || 64K (4/4/3 levels depending on page size)
>
> That's more meaningful to people configuring the kernel.

Okay, I will revise VA_BITS config as hiding the number of levels.

Best Regards
Jungseok Lee