Re: [PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Ard Biesheuvel]

On 2 September 2015 at 11:42, Suzuki K. Poulose  wrote:
> On 02/09/15 10:38, Ard Biesheuvel wrote:
>>
>> On 13 August 2015 at 13:33, Suzuki K. Poulose 
>> wrote:
>>>
>>> From: "Suzuki K. Poulose" 
>>>
>>> We use section maps with 4K page size to create the
>>> swapper/idmaps. So far we have used !64K or 4K checks
>>> to handle the case where we use the section maps. This
>>> patch adds a symbol to make it clear those cases.
>>>
>>
>> That sentence does not make sense.
>
>
> I agree. How about :
>
> "This patch adds a new symbol, 'ARM64_SWAPPER_USES_SECTION_MAPS', to
> handle cases where we use section maps, instead of using the page size
> symbols."
>

Yep, much better
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Suzuki K. Poulose]

On 02/09/15 10:38, Ard Biesheuvel wrote:

On 13 August 2015 at 13:33, Suzuki K. Poulose  wrote:

From: "Suzuki K. Poulose" 

We use section maps with 4K page size to create the
swapper/idmaps. So far we have used !64K or 4K checks
to handle the case where we use the section maps. This
patch adds a symbol to make it clear those cases.



That sentence does not make sense.


I agree. How about :

"This patch adds a new symbol, 'ARM64_SWAPPER_USES_SECTION_MAPS', to
handle cases where we use section maps, instead of using the page size
symbols."

Suzuki


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Ard Biesheuvel]

On 13 August 2015 at 13:33, Suzuki K. Poulose  wrote:
> From: "Suzuki K. Poulose" 
>
> We use section maps with 4K page size to create the
> swapper/idmaps. So far we have used !64K or 4K checks
> to handle the case where we use the section maps. This
> patch adds a symbol to make it clear those cases.
>

That sentence does not make sense.

> Cc: Ard Biesheuvel 
> Cc: Mark Rutland 
> Cc: Catalin Marinas 
> Cc: Will Deacon 
> Signed-off-by: Suzuki K. Poulose 
> ---
>  arch/arm64/include/asm/kernel-pgtable.h |   31 +-
>  arch/arm64/mm/mmu.c |   70 
> ++-
>  2 files changed, 51 insertions(+), 50 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kernel-pgtable.h 
> b/arch/arm64/include/asm/kernel-pgtable.h
> index 622929d..5876a36 100644
> --- a/arch/arm64/include/asm/kernel-pgtable.h
> +++ b/arch/arm64/include/asm/kernel-pgtable.h
> @@ -19,6 +19,13 @@
>  #ifndef __ASM_KERNEL_PGTABLE_H
>  #define __ASM_KERNEL_PGTABLE_H
>
> +/* With 4K pages, we use section maps. */
> +#ifdef CONFIG_ARM64_4K_PAGES
> +#define ARM64_SWAPPER_USES_SECTION_MAPS 1
> +#else
> +#define ARM64_SWAPPER_USES_SECTION_MAPS 0
> +#endif
> +
>  /*
>   * The idmap and swapper page tables need some space reserved in the kernel
>   * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
> @@ -28,26 +35,28 @@
>   * could be increased on the fly if system RAM is out of reach for the 
> default
>   * VA range, so 3 pages are reserved in all cases.
>   */
> -#ifdef CONFIG_ARM64_64K_PAGES
> -#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
> -#else
> +#if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
> +#else
> +#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
>  #endif
>
>  #define SWAPPER_DIR_SIZE   (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
>  #define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
>
>  /* Initial memory map size */
> -#ifdef CONFIG_ARM64_64K_PAGES
> -#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
> -#define SWAPPER_BLOCK_SIZE PAGE_SIZE
> -#define SWAPPER_TABLE_SHIFTPMD_SHIFT
> -#else
> +#if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_BLOCK_SHIFTSECTION_SHIFT
>  #define SWAPPER_BLOCK_SIZE SECTION_SIZE
>  #define SWAPPER_TABLE_SHIFTPUD_SHIFT
> +#else
> +#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
> +#define SWAPPER_BLOCK_SIZE PAGE_SIZE
> +#define SWAPPER_TABLE_SHIFTPMD_SHIFT
>  #endif
>
> +/* The size of the initial kernel direct mapping */
> +#define SWAPPER_INIT_MAP_SIZE  (_AC(1, UL) << SWAPPER_TABLE_SHIFT)
>
>  /*
>   * Initial memory map attributes.
> @@ -55,10 +64,10 @@
>  #define SWAPPER_PTE_FLAGS  PTE_TYPE_PAGE | PTE_AF | PTE_SHARED
>  #define SWAPPER_PMD_FLAGS  PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S
>
> -#ifdef CONFIG_ARM64_64K_PAGES
> -#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
> -#else
> +#if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_MM_MMUFLAGSPMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS
> +#else
> +#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
>  #endif
>
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 9211b85..71230488 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -32,6 +32,7 @@
>
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -353,14 +354,11 @@ static void __init map_mem(void)
>  * memory addressable from the initial direct kernel mapping.
>  *
>  * The initial direct kernel mapping, located at swapper_pg_dir, gives
> -* us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
> -* PHYS_OFFSET (which must be aligned to 2MB as per
> -* Documentation/arm64/booting.txt).
> +* us PUD_SIZE (with SECTION maps, i.e, 4K) or PMD_SIZE (without
> +* SECTION maps, i.e, 64K pages) memory starting from PHYS_OFFSET
> +* (which must be aligned to 2MB as per 
> Documentation/arm64/booting.txt).
>  */
> -   if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
> -   limit = PHYS_OFFSET + PMD_SIZE;
> -   else
> -   limit = PHYS_OFFSET + PUD_SIZE;
> +   limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE;
> memblock_set_current_limit(limit);
>
> /* map all the memory banks */
> @@ -371,21 +369,24 @@ static void __init map_mem(void)
> if (start >= end)
> break;
>
> -#ifndef CONFIG_ARM64_64K_PAGES
> -   /*
> -* For the first memory bank align the start address and
> -* current memblock limit to prevent create_mapping() from
> -* allocating pte page tables from unmapped memory.
> -* When 64K pages are enabled, the pte page table for the
> -* first PGDIR_SIZE is already present in swapper_pg_dir.
> -*/
> -   if (start < limit)
> -   

Re: [PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Ard Biesheuvel]

On 2 September 2015 at 11:42, Suzuki K. Poulose  wrote:
> On 02/09/15 10:38, Ard Biesheuvel wrote:
>>
>> On 13 August 2015 at 13:33, Suzuki K. Poulose 
>> wrote:
>>>
>>> From: "Suzuki K. Poulose" 
>>>
>>> We use section maps with 4K page size to create the
>>> swapper/idmaps. So far we have used !64K or 4K checks
>>> to handle the case where we use the section maps. This
>>> patch adds a symbol to make it clear those cases.
>>>
>>
>> That sentence does not make sense.
>
>
> I agree. How about :
>
> "This patch adds a new symbol, 'ARM64_SWAPPER_USES_SECTION_MAPS', to
> handle cases where we use section maps, instead of using the page size
> symbols."
>

Yep, much better
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Ard Biesheuvel]

On 13 August 2015 at 13:33, Suzuki K. Poulose  wrote:
> From: "Suzuki K. Poulose" 
>
> We use section maps with 4K page size to create the
> swapper/idmaps. So far we have used !64K or 4K checks
> to handle the case where we use the section maps. This
> patch adds a symbol to make it clear those cases.
>

That sentence does not make sense.

> Cc: Ard Biesheuvel 
> Cc: Mark Rutland 
> Cc: Catalin Marinas 
> Cc: Will Deacon 
> Signed-off-by: Suzuki K. Poulose 
> ---
>  arch/arm64/include/asm/kernel-pgtable.h |   31 +-
>  arch/arm64/mm/mmu.c |   70 
> ++-
>  2 files changed, 51 insertions(+), 50 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kernel-pgtable.h 
> b/arch/arm64/include/asm/kernel-pgtable.h
> index 622929d..5876a36 100644
> --- a/arch/arm64/include/asm/kernel-pgtable.h
> +++ b/arch/arm64/include/asm/kernel-pgtable.h
> @@ -19,6 +19,13 @@
>  #ifndef __ASM_KERNEL_PGTABLE_H
>  #define __ASM_KERNEL_PGTABLE_H
>
> +/* With 4K pages, we use section maps. */
> +#ifdef CONFIG_ARM64_4K_PAGES
> +#define ARM64_SWAPPER_USES_SECTION_MAPS 1
> +#else
> +#define ARM64_SWAPPER_USES_SECTION_MAPS 0
> +#endif
> +
>  /*
>   * The idmap and swapper page tables need some space reserved in the kernel
>   * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
> @@ -28,26 +35,28 @@
>   * could be increased on the fly if system RAM is out of reach for the 
> default
>   * VA range, so 3 pages are reserved in all cases.
>   */
> -#ifdef CONFIG_ARM64_64K_PAGES
> -#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
> -#else
> +#if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
> +#else
> +#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
>  #endif
>
>  #define SWAPPER_DIR_SIZE   (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
>  #define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
>
>  /* Initial memory map size */
> -#ifdef CONFIG_ARM64_64K_PAGES
> -#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
> -#define SWAPPER_BLOCK_SIZE PAGE_SIZE
> -#define SWAPPER_TABLE_SHIFTPMD_SHIFT
> -#else
> +#if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_BLOCK_SHIFTSECTION_SHIFT
>  #define SWAPPER_BLOCK_SIZE SECTION_SIZE
>  #define SWAPPER_TABLE_SHIFTPUD_SHIFT
> +#else
> +#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
> +#define SWAPPER_BLOCK_SIZE PAGE_SIZE
> +#define SWAPPER_TABLE_SHIFTPMD_SHIFT
>  #endif
>
> +/* The size of the initial kernel direct mapping */
> +#define SWAPPER_INIT_MAP_SIZE  (_AC(1, UL) << SWAPPER_TABLE_SHIFT)
>
>  /*
>   * Initial memory map attributes.
> @@ -55,10 +64,10 @@
>  #define SWAPPER_PTE_FLAGS  PTE_TYPE_PAGE | PTE_AF | PTE_SHARED
>  #define SWAPPER_PMD_FLAGS  PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S
>
> -#ifdef CONFIG_ARM64_64K_PAGES
> -#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
> -#else
> +#if ARM64_SWAPPER_USES_SECTION_MAPS
>  #define SWAPPER_MM_MMUFLAGSPMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS
> +#else
> +#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
>  #endif
>
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 9211b85..71230488 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -32,6 +32,7 @@
>
>  #include 
>  #include 
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -353,14 +354,11 @@ static void __init map_mem(void)
>  * memory addressable from the initial direct kernel mapping.
>  *
>  * The initial direct kernel mapping, located at swapper_pg_dir, gives
> -* us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
> -* PHYS_OFFSET (which must be aligned to 2MB as per
> -* Documentation/arm64/booting.txt).
> +* us PUD_SIZE (with SECTION maps, i.e, 4K) or PMD_SIZE (without
> +* SECTION maps, i.e, 64K pages) memory starting from PHYS_OFFSET
> +* (which must be aligned to 2MB as per 
> Documentation/arm64/booting.txt).
>  */
> -   if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
> -   limit = PHYS_OFFSET + PMD_SIZE;
> -   else
> -   limit = PHYS_OFFSET + PUD_SIZE;
> +   limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE;
> memblock_set_current_limit(limit);
>
> /* map all the memory banks */
> @@ -371,21 +369,24 @@ static void __init map_mem(void)
> if (start >= end)
> break;
>
> -#ifndef CONFIG_ARM64_64K_PAGES
> -   /*
> -* For the first memory bank align the start address and
> -* current memblock limit to prevent create_mapping() from
> -* allocating pte page tables from unmapped memory.
> -* When 64K pages are enabled, the pte page table for 

Re: [PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Suzuki K. Poulose]

On 02/09/15 10:38, Ard Biesheuvel wrote:

On 13 August 2015 at 13:33, Suzuki K. Poulose  wrote:

From: "Suzuki K. Poulose" 

We use section maps with 4K page size to create the
swapper/idmaps. So far we have used !64K or 4K checks
to handle the case where we use the section maps. This
patch adds a symbol to make it clear those cases.



That sentence does not make sense.


I agree. How about :

"This patch adds a new symbol, 'ARM64_SWAPPER_USES_SECTION_MAPS', to
handle cases where we use section maps, instead of using the page size
symbols."

Suzuki


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Suzuki K. Poulose]

From: "Suzuki K. Poulose" 

We use section maps with 4K page size to create the
swapper/idmaps. So far we have used !64K or 4K checks
to handle the case where we use the section maps. This
patch adds a symbol to make it clear those cases.

Cc: Ard Biesheuvel 
Cc: Mark Rutland 
Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Suzuki K. Poulose 
---
 arch/arm64/include/asm/kernel-pgtable.h |   31 +-
 arch/arm64/mm/mmu.c |   70 ++-
 2 files changed, 51 insertions(+), 50 deletions(-)

diff --git a/arch/arm64/include/asm/kernel-pgtable.h 
b/arch/arm64/include/asm/kernel-pgtable.h
index 622929d..5876a36 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -19,6 +19,13 @@
 #ifndef __ASM_KERNEL_PGTABLE_H
 #define __ASM_KERNEL_PGTABLE_H
 
+/* With 4K pages, we use section maps. */
+#ifdef CONFIG_ARM64_4K_PAGES
+#define ARM64_SWAPPER_USES_SECTION_MAPS 1
+#else
+#define ARM64_SWAPPER_USES_SECTION_MAPS 0
+#endif
+
 /*
  * The idmap and swapper page tables need some space reserved in the kernel
  * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
@@ -28,26 +35,28 @@
  * could be increased on the fly if system RAM is out of reach for the default
  * VA range, so 3 pages are reserved in all cases.
  */
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
+#else
+#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
 #endif
 
 #define SWAPPER_DIR_SIZE   (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
 #define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
 
 /* Initial memory map size */
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
-#define SWAPPER_BLOCK_SIZE PAGE_SIZE
-#define SWAPPER_TABLE_SHIFTPMD_SHIFT
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_BLOCK_SHIFTSECTION_SHIFT
 #define SWAPPER_BLOCK_SIZE SECTION_SIZE
 #define SWAPPER_TABLE_SHIFTPUD_SHIFT
+#else
+#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
+#define SWAPPER_BLOCK_SIZE PAGE_SIZE
+#define SWAPPER_TABLE_SHIFTPMD_SHIFT
 #endif
 
+/* The size of the initial kernel direct mapping */
+#define SWAPPER_INIT_MAP_SIZE  (_AC(1, UL) << SWAPPER_TABLE_SHIFT)
 
 /*
  * Initial memory map attributes.
@@ -55,10 +64,10 @@
 #define SWAPPER_PTE_FLAGS  PTE_TYPE_PAGE | PTE_AF | PTE_SHARED
 #define SWAPPER_PMD_FLAGS  PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S
 
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_MM_MMUFLAGSPMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS
+#else
+#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
 #endif
 
 
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9211b85..71230488 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -32,6 +32,7 @@
 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -353,14 +354,11 @@ static void __init map_mem(void)
 * memory addressable from the initial direct kernel mapping.
 *
 * The initial direct kernel mapping, located at swapper_pg_dir, gives
-* us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
-* PHYS_OFFSET (which must be aligned to 2MB as per
-* Documentation/arm64/booting.txt).
+* us PUD_SIZE (with SECTION maps, i.e, 4K) or PMD_SIZE (without
+* SECTION maps, i.e, 64K pages) memory starting from PHYS_OFFSET
+* (which must be aligned to 2MB as per 
Documentation/arm64/booting.txt).
 */
-   if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
-   limit = PHYS_OFFSET + PMD_SIZE;
-   else
-   limit = PHYS_OFFSET + PUD_SIZE;
+   limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE;
memblock_set_current_limit(limit);
 
/* map all the memory banks */
@@ -371,21 +369,24 @@ static void __init map_mem(void)
if (start >= end)
break;
 
-#ifndef CONFIG_ARM64_64K_PAGES
-   /*
-* For the first memory bank align the start address and
-* current memblock limit to prevent create_mapping() from
-* allocating pte page tables from unmapped memory.
-* When 64K pages are enabled, the pte page table for the
-* first PGDIR_SIZE is already present in swapper_pg_dir.
-*/
-   if (start < limit)
-   start = ALIGN(start, PMD_SIZE);
-   if (end < limit) {
-   limit = end & PMD_MASK;
-   memblock_set_current_limit(limit);
+   if (ARM64_SWAPPER_USES_SECTION_MAPS) {
+   /*
+* For the first memory bank align the start address and
+  

[PATCH 02/14] arm64: Handle section maps for swapper/idmap

[Suzuki K. Poulose]

From: Suzuki K. Poulose suzuki.poul...@arm.com

We use section maps with 4K page size to create the
swapper/idmaps. So far we have used !64K or 4K checks
to handle the case where we use the section maps. This
patch adds a symbol to make it clear those cases.

Cc: Ard Biesheuvel ard.biesheu...@linaro.org
Cc: Mark Rutland mark.rutl...@arm.com
Cc: Catalin Marinas catalin.mari...@arm.com
Cc: Will Deacon will.dea...@arm.com
Signed-off-by: Suzuki K. Poulose suzuki.poul...@arm.com
---
 arch/arm64/include/asm/kernel-pgtable.h |   31 +-
 arch/arm64/mm/mmu.c |   70 ++-
 2 files changed, 51 insertions(+), 50 deletions(-)

diff --git a/arch/arm64/include/asm/kernel-pgtable.h 
b/arch/arm64/include/asm/kernel-pgtable.h
index 622929d..5876a36 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -19,6 +19,13 @@
 #ifndef __ASM_KERNEL_PGTABLE_H
 #define __ASM_KERNEL_PGTABLE_H
 
+/* With 4K pages, we use section maps. */
+#ifdef CONFIG_ARM64_4K_PAGES
+#define ARM64_SWAPPER_USES_SECTION_MAPS 1
+#else
+#define ARM64_SWAPPER_USES_SECTION_MAPS 0
+#endif
+
 /*
  * The idmap and swapper page tables need some space reserved in the kernel
  * image. Both require pgd, pud (4 levels only) and pmd tables to (section)
@@ -28,26 +35,28 @@
  * could be increased on the fly if system RAM is out of reach for the default
  * VA range, so 3 pages are reserved in all cases.
  */
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
+#else
+#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
 #endif
 
 #define SWAPPER_DIR_SIZE   (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
 #define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
 
 /* Initial memory map size */
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
-#define SWAPPER_BLOCK_SIZE PAGE_SIZE
-#define SWAPPER_TABLE_SHIFTPMD_SHIFT
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_BLOCK_SHIFTSECTION_SHIFT
 #define SWAPPER_BLOCK_SIZE SECTION_SIZE
 #define SWAPPER_TABLE_SHIFTPUD_SHIFT
+#else
+#define SWAPPER_BLOCK_SHIFTPAGE_SHIFT
+#define SWAPPER_BLOCK_SIZE PAGE_SIZE
+#define SWAPPER_TABLE_SHIFTPMD_SHIFT
 #endif
 
+/* The size of the initial kernel direct mapping */
+#define SWAPPER_INIT_MAP_SIZE  (_AC(1, UL)  SWAPPER_TABLE_SHIFT)
 
 /*
  * Initial memory map attributes.
@@ -55,10 +64,10 @@
 #define SWAPPER_PTE_FLAGS  PTE_TYPE_PAGE | PTE_AF | PTE_SHARED
 #define SWAPPER_PMD_FLAGS  PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S
 
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
 #define SWAPPER_MM_MMUFLAGSPMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS
+#else
+#define SWAPPER_MM_MMUFLAGSPTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS
 #endif
 
 
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 9211b85..71230488 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -32,6 +32,7 @@
 
 #include asm/cputype.h
 #include asm/fixmap.h
+#include asm/kernel-pgtable.h
 #include asm/sections.h
 #include asm/setup.h
 #include asm/sizes.h
@@ -353,14 +354,11 @@ static void __init map_mem(void)
 * memory addressable from the initial direct kernel mapping.
 *
 * The initial direct kernel mapping, located at swapper_pg_dir, gives
-* us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
-* PHYS_OFFSET (which must be aligned to 2MB as per
-* Documentation/arm64/booting.txt).
+* us PUD_SIZE (with SECTION maps, i.e, 4K) or PMD_SIZE (without
+* SECTION maps, i.e, 64K pages) memory starting from PHYS_OFFSET
+* (which must be aligned to 2MB as per 
Documentation/arm64/booting.txt).
 */
-   if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
-   limit = PHYS_OFFSET + PMD_SIZE;
-   else
-   limit = PHYS_OFFSET + PUD_SIZE;
+   limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE;
memblock_set_current_limit(limit);
 
/* map all the memory banks */
@@ -371,21 +369,24 @@ static void __init map_mem(void)
if (start = end)
break;
 
-#ifndef CONFIG_ARM64_64K_PAGES
-   /*
-* For the first memory bank align the start address and
-* current memblock limit to prevent create_mapping() from
-* allocating pte page tables from unmapped memory.
-* When 64K pages are enabled, the pte page table for the
-* first PGDIR_SIZE is already present in swapper_pg_dir.
-*/
-   if (start  limit)
-   start = ALIGN(start, PMD_SIZE);
-   if (end  limit) {
-   limit = end  PMD_MASK;
-