On Tue, Aug 31, 2021 at 09:15:30AM +0530, Anshuman Khandual wrote:

On 8/21/21 12:05 AM, Catalin Marinas wrote:

quoted

On Fri, Aug 20, 2021 at 04:35:16PM +0530, Anshuman Khandual wrote:

quoted

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.

quoted

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

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