ARM: mm: Make virt_to_pfn() a static inline

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Doing this is a bit intrusive: virt_to_pfn() requires
PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in
<asm/page.h>, so this must be included *before* <asm/memory.h>.

The use of macros were obscuring the unclear inclusion order here,
as the macros would eventually be resolved, but a static inline
like this cannot be compiled with unresolved macros.

The naive solution to include <asm/page.h> at the top of
<asm/memory.h> does not work, because <asm/memory.h> sometimes
includes <asm/page.h> at the end of itself, which would create a
confusing inclusion loop. So instead, take the approach to always
unconditionally include <asm/page.h> at the end of <asm/memory.h>

arch/arm uses <asm/memory.h> explicitly in a lot of places,
however it turns out that if we just unconditionally include
<asm/memory.h> into <asm/page.h> and switch all inclusions of
<asm/memory.h> to <asm/page.h> instead, we enforce the right
order and <asm/memory.h> will always have access to the
definitions.

Put an inclusion guard in place making it impossible to include
<asm/memory.h> explicitly.

Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

12 files changed, 9 insertions, 12 deletions

diff --git a/arch/arm/mm/cache-fa.S b/arch/arm/mm/cache-fa.S
index 3a464d1649b4..71c64e92dead 100644
--- a/arch/arm/mm/cache-fa.S
+++ b/arch/arm/mm/cache-fa.S
@@ -13,7 +13,6 @@
 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/assembler.h>
-#include <asm/memory.h>
 #include <asm/page.h>
 
 #include "proc-macros.S"
diff --git a/arch/arm/mm/cache-v4wb.S b/arch/arm/mm/cache-v4wb.S
index 905ac2fa2b1e..ad382cee0fdb 100644
--- a/arch/arm/mm/cache-v4wb.S
+++ b/arch/arm/mm/cache-v4wb.S
@@ -7,7 +7,6 @@
 #include <linux/linkage.h>
 #include <linux/init.h>
 #include <asm/assembler.h>
-#include <asm/memory.h>
 #include <asm/page.h>
 #include "proc-macros.S"
 
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index b4a33358d2e9..0549bee68a67 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -25,7 +25,7 @@
 #include <linux/sizes.h>
 #include <linux/cma.h>
 
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/highmem.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
index 059eb4cdc9c2..a9381095ab36 100644
--- a/arch/arm/mm/dump.c
+++ b/arch/arm/mm/dump.c
@@ -15,7 +15,7 @@
 
 #include <asm/domain.h>
 #include <asm/fixmap.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/ptdump.h>
 
 static struct addr_marker address_markers[] = {
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index ce64bdb55a16..a42e4cd11db2 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -26,7 +26,7 @@
 #include <asm/cp15.h>
 #include <asm/mach-types.h>
 #include <asm/memblock.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/prom.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c
index 46d9f4a622cb..24d71b5db62d 100644
--- a/arch/arm/mm/kasan_init.c
+++ b/arch/arm/mm/kasan_init.c
@@ -17,7 +17,6 @@
 #include <asm/cputype.h>
 #include <asm/highmem.h>
 #include <asm/mach/map.h>
-#include <asm/memory.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <asm/procinfo.h>
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 463fc2a8448f..22292cf3381c 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -26,7 +26,7 @@
 #include <asm/system_info.h>
 #include <asm/traps.h>
 #include <asm/procinfo.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <asm/kasan_def.h>
 
diff --git a/arch/arm/mm/physaddr.c b/arch/arm/mm/physaddr.c
index cf75819e4c13..3f263c840ebc 100644
--- a/arch/arm/mm/physaddr.c
+++ b/arch/arm/mm/physaddr.c
@@ -6,7 +6,7 @@
 #include <linux/mm.h>
 
 #include <asm/sections.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/fixmap.h>
 #include <asm/dma.h>
 
diff --git a/arch/arm/mm/pmsa-v8.c b/arch/arm/mm/pmsa-v8.c
index 8359748a19a1..28cdc5468406 100644
--- a/arch/arm/mm/pmsa-v8.c
+++ b/arch/arm/mm/pmsa-v8.c
@@ -11,7 +11,7 @@
 #include <asm/cputype.h>
 #include <asm/mpu.h>
 
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/sections.h>
 
 #include "mm.h"
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 6b4ef9539b68..193c7aeb6703 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -14,7 +14,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/hwcap.h>
 #include <asm/pgtable-hwdef.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 
 #include "proc-macros.S"
 
diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
index 335144d50134..d65a12f851a9 100644
--- a/arch/arm/mm/proc-v7m.S
+++ b/arch/arm/mm/proc-v7m.S
@@ -9,7 +9,7 @@
  */
 #include <linux/linkage.h>
 #include <asm/assembler.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/v7m.h>
 #include "proc-macros.S"
 
diff --git a/arch/arm/mm/pv-fixup-asm.S b/arch/arm/mm/pv-fixup-asm.S
index f8e11f7c7880..1d9f52c71ad0 100644
--- a/arch/arm/mm/pv-fixup-asm.S
+++ b/arch/arm/mm/pv-fixup-asm.S
@@ -9,7 +9,7 @@
 #include <linux/pgtable.h>
 #include <asm/asm-offsets.h>
 #include <asm/cp15.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 
 	.section ".idmap.text", "ax"