[PATCH V2] arm64/mm: Drop <asm/page-def.h>

[PATCH V2] arm64/mm: Drop <asm/page-def.h>

[Anshuman Khandual]

PAGE_SHIFT (PAGE_SIZE and PAGE_MASK) which is derived from ARM64_PAGE_SHIFT
should be moved into <asm/page.h> instead like in case for other platforms,
and then subsequently <asm/page-def.h> can be just dropped off completely.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on 5.14-rc6.

Changes in V2:

- Moved PAGE_XXX macros into <asm/page.h> instead of <asm/pgtable-hwdef.h>
- Changed the commit message accordingly

Changes in V1:

https://lore.kernel.org/lkml/1629441331-19530-1-git-send-email-anshuman.khandual@arm.com/

 arch/arm64/include/asm/memory.h   |  2 +-
 arch/arm64/include/asm/page-def.h | 18 ------------------
 arch/arm64/include/asm/page.h     |  4 +++-
 3 files changed, 4 insertions(+), 20 deletions(-)
 delete mode 100644 arch/arm64/include/asm/page-def.h

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 824a3655dd93..649d26396f9e 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -12,7 +12,7 @@
 
 #include <linux/const.h>
 #include <linux/sizes.h>
-#include <asm/page-def.h>
+#include <asm/page.h>
 
 /*
  * Size of the PCI I/O space. This must remain a power of two so that
diff --git a/arch/arm64/include/asm/page-def.h b/arch/arm64/include/asm/page-def.h
deleted file mode 100644
index 2403f7b4cdbf..000000000000
--- a/arch/arm64/include/asm/page-def.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Based on arch/arm/include/asm/page.h
- *
- * Copyright (C) 1995-2003 Russell King
- * Copyright (C) 2017 ARM Ltd.
- */
-#ifndef __ASM_PAGE_DEF_H
-#define __ASM_PAGE_DEF_H
-
-#include <linux/const.h>
-
-/* PAGE_SHIFT determines the page size */
-#define PAGE_SHIFT		CONFIG_ARM64_PAGE_SHIFT
-#define PAGE_SIZE		(_AC(1, UL) << PAGE_SHIFT)
-#define PAGE_MASK		(~(PAGE_SIZE-1))
-
-#endif /* __ASM_PAGE_DEF_H */
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 993a27ea6f54..95c58b00bb71 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -8,7 +8,9 @@
 #ifndef __ASM_PAGE_H
 #define __ASM_PAGE_H
 
-#include <asm/page-def.h>
+#define PAGE_SHIFT		CONFIG_ARM64_PAGE_SHIFT
+#define PAGE_SIZE		(_AC(1, UL) << PAGE_SHIFT)
+#define PAGE_MASK		(~(PAGE_SIZE-1))
 
 #ifndef __ASSEMBLY__
 
-- 
2.20.1

Re: [PATCH V2] arm64/mm: Drop <asm/page-def.h>

[Catalin Marinas]

On Fri, Aug 20, 2021 at 04:35:16PM +0530, Anshuman Khandual wrote:
> PAGE_SHIFT (PAGE_SIZE and PAGE_MASK) which is derived from ARM64_PAGE_SHIFT
> should be moved into <asm/page.h> instead like in case for other platforms,
> and then subsequently <asm/page-def.h> can be just dropped off completely.

These were moved to page-def.h as part of commit b6531456ba27 ("arm64:
factor out PAGE_* and CONT_* definitions") to avoid some circular header
dependencies.

> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index 824a3655dd93..649d26396f9e 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -12,7 +12,7 @@
>  
>  #include <linux/const.h>
>  #include <linux/sizes.h>
> -#include <asm/page-def.h>
> +#include <asm/page.h>

In 5.14-rc3, asm/page.h still includes asm/memory.h.

-- 
Catalin

Re: [PATCH V2] arm64/mm: Drop <asm/page-def.h>

[Anshuman Khandual]

On 8/21/21 12:05 AM, Catalin Marinas wrote:
> On Fri, Aug 20, 2021 at 04:35:16PM +0530, Anshuman Khandual wrote:
>> PAGE_SHIFT (PAGE_SIZE and PAGE_MASK) which is derived from ARM64_PAGE_SHIFT
>> should be moved into <asm/page.h> instead like in case for other platforms,
>> and then subsequently <asm/page-def.h> can be just dropped off completely.
> 
> These were moved to page-def.h as part of commit b6531456ba27 ("arm64:
> factor out PAGE_* and CONT_* definitions") to avoid some circular header
> dependencies.
> 
>> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
>> index 824a3655dd93..649d26396f9e 100644
>> --- a/arch/arm64/include/asm/memory.h
>> +++ b/arch/arm64/include/asm/memory.h
>> @@ -12,7 +12,7 @@
>>  
>>  #include <linux/const.h>
>>  #include <linux/sizes.h>
>> -#include <asm/page-def.h>
>> +#include <asm/page.h>
> 
> In 5.14-rc3, asm/page.h still includes asm/memory.h.

Dropping <asm/memory.h> from <asm/page.h> does not seem to cause
any problem, will change that. Afterwards build tested it across
page sizes and also with some random configs. Is that circular
dependency still present ? Also wondering why was <asm/memory.h>
included in <asm/page.h> to begin with ?

Re: [PATCH V2] arm64/mm: Drop <asm/page-def.h>

[Catalin Marinas]

On Tue, Aug 31, 2021 at 09:15:30AM +0530, Anshuman Khandual wrote:
> On 8/21/21 12:05 AM, Catalin Marinas wrote:
> > On Fri, Aug 20, 2021 at 04:35:16PM +0530, Anshuman Khandual wrote:
> >> PAGE_SHIFT (PAGE_SIZE and PAGE_MASK) which is derived from ARM64_PAGE_SHIFT
> >> should be moved into <asm/page.h> instead like in case for other platforms,
> >> and then subsequently <asm/page-def.h> can be just dropped off completely.
> > 
> > These were moved to page-def.h as part of commit b6531456ba27 ("arm64:
> > factor out PAGE_* and CONT_* definitions") to avoid some circular header
> > dependencies.
> > 
> >> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> >> index 824a3655dd93..649d26396f9e 100644
> >> --- a/arch/arm64/include/asm/memory.h
> >> +++ b/arch/arm64/include/asm/memory.h
> >> @@ -12,7 +12,7 @@
> >>  
> >>  #include <linux/const.h>
> >>  #include <linux/sizes.h>
> >> -#include <asm/page-def.h>
> >> +#include <asm/page.h>
> > 
> > In 5.14-rc3, asm/page.h still includes asm/memory.h.
> 
> Dropping <asm/memory.h> from <asm/page.h> does not seem to cause
> any problem, will change that. Afterwards build tested it across
> page sizes and also with some random configs. Is that circular
> dependency still present ? Also wondering why was <asm/memory.h>
> included in <asm/page.h> to begin with ?

asm/memory.h is not included by any of the generic files, however it has
essential definitions like PAGE_OFFSET, THREAD_SIZE. The expectations
from the arch code is to have these defined in asm/page.h (see the
asm-generic/page.h), hence the inclusion. It probably gets included by
other arch headers and that's why you don't get any errors, but I
wouldn't rely on this.

I don't remember how we ended up with a separate memory.h file. On arm64
we inherited it from arch/arm.

-- 
Catalin