[PATCH v6 2/7] arm64: Introduce VA_BITS and translation level options

From: Jungseok Lee
Date: Mon May 12 2014 - 05:40:48 EST

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This patch adds virtual address space size and a level of translation
tables to kernel configuration. It facilicates introduction of
different MMU options, such as 4KB + 4 levels, 16KB + 4 levels and
64KB + 3 levels, easily.

The idea is based on the discussion with Catalin Marinas:
http://www.spinics.net/linux/lists/arm-kernel/msg319552.html

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxxxxx>
Signed-off-by: Jungseok Lee <jays.lee@xxxxxxxxxxx>
Reviewed-by: Sungjinn Chung <sungjinn.chung@xxxxxxxxxxx>
Acked-by: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
---
arch/arm64/Kconfig | 45 +++++++++++++++++++++++++++++++-
arch/arm64/include/asm/memory.h | 6 +----
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 +-
7 files changed, 54 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9a5b5fe..9a28cbe 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -144,14 +144,57 @@ 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 "Virtual address space size"
+ default ARM64_VA_BITS_39 if ARM64_4K_PAGES
+ default ARM64_VA_BITS_42 if ARM64_64K_PAGES
+ help
+ Allows choosing one of multiple possible virtual address
+ space sizes. The level of translation table is determined by
+ a combination of page size and virtual address space size.
+
+config ARM64_VA_BITS_39
+ bool "39-bit"
+ depends on ARM64_4K_PAGES
+
+config ARM64_VA_BITS_42
+ bool "42-bit"
+ depends on ARM64_64K_PAGES
+
+endchoice
+
+config ARM64_VA_BITS
+ int
+ default 39 if ARM64_VA_BITS_39
+ default 42 if ARM64_VA_BITS_42
+
+config ARM64_2_LEVELS
+ def_bool y if ARM64_64K_PAGES && ARM64_VA_BITS_42
+
+config ARM64_3_LEVELS
+ def_bool y if ARM64_4K_PAGES && ARM64_VA_BITS_39
+
config CPU_BIG_ENDIAN
bool "Build big-endian kernel"
help
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index e94f945..f6e7480 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -41,11 +41,7 @@
* The module space lives between the addresses given by TASK_SIZE
* and PAGE_OFFSET - it must be within 128MB of the kernel text.
*/
-#ifdef CONFIG_ARM64_64K_PAGES
-#define VA_BITS (42)
-#else
-#define VA_BITS (39)
-#endif
+#define VA_BITS (CONFIG_ARM64_VA_BITS)
#define PAGE_OFFSET (UL(0xffffffffffffffff) << (VA_BITS - 1))
#define MODULES_END (PAGE_OFFSET)
#define MODULES_VADDR (MODULES_END - SZ_64M)
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 955e8c5..c7c603b 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 e4c60d6..4a350af 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))
@@ -324,7 +324,7 @@ 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))
@@ -346,7 +346,7 @@ 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))
@@ -357,7 +357,7 @@ 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

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Next message: Jungseok Lee: "[PATCH v6 5/7] arm64: mm: Implement 4 levels of translation tables"
Previous message: Jungseok Lee: "[PATCH v6 1/7] arm64: Use pr_* instead of printk"
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