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>

11 files changed, 11 insertions, 14 deletions

diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index 38121c59cbc2..6a80d4be743b 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -17,7 +17,7 @@
 #include <asm/glue-pf.h>
 #include <asm/mach/arch.h>
 #include <asm/thread_info.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/mpu.h>
 #include <asm/procinfo.h>
 #include <asm/suspend.h>
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index c39303e5c234..112fd6cd3f26 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -15,7 +15,7 @@
 #include <linux/init.h>
 
 #include <asm/assembler.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/glue-df.h>
 #include <asm/glue-pf.h>
 #include <asm/vfpmacros.h>
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 03d4c5578c5c..bcc4c9ec3aa4 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -9,7 +9,7 @@
 #include <asm/unistd.h>
 #include <asm/ftrace.h>
 #include <asm/unwind.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #ifdef CONFIG_AEABI
 #include <asm/unistd-oabi.h>
 #endif
diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
index de8a60363c85..52bacf07ba16 100644
--- a/arch/arm/kernel/entry-v7m.S
+++ b/arch/arm/kernel/entry-v7m.S
@@ -6,7 +6,7 @@
  *
  * Low-level vector interface routines for the ARMv7-M architecture
  */
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/glue.h>
 #include <asm/thread_notify.h>
 #include <asm/v7m.h>
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index 950bef83339f..b9d6818f1ee1 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -14,12 +14,11 @@
 #include <asm/assembler.h>
 #include <asm/ptrace.h>
 #include <asm/asm-offsets.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/cp15.h>
 #include <asm/thread_info.h>
 #include <asm/v7m.h>
 #include <asm/mpu.h>
-#include <asm/page.h>
 
 /*
  * Kernel startup entry point.
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 656991055bc1..1ec35f065617 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -17,7 +17,7 @@
 #include <asm/domain.h>
 #include <asm/ptrace.h>
 #include <asm/asm-offsets.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/thread_info.h>
 
 #if defined(CONFIG_DEBUG_LL) && !defined(CONFIG_DEBUG_SEMIHOSTING)
diff --git a/arch/arm/kernel/hibernate.c b/arch/arm/kernel/hibernate.c
index 2373020af965..38a90a3d12b2 100644
--- a/arch/arm/kernel/hibernate.c
+++ b/arch/arm/kernel/hibernate.c
@@ -19,7 +19,7 @@
 #include <asm/system_misc.h>
 #include <asm/idmap.h>
 #include <asm/suspend.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/sections.h>
 #include "reboot.h"
 
diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
index 43f0a3ebf390..c3ec3861dd07 100644
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -8,7 +8,7 @@
 #include <asm/bugs.h>
 #include <asm/cacheflush.h>
 #include <asm/idmap.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/smp_plat.h>
 #include <asm/suspend.h>
 #include <asm/tlbflush.h>
diff --git a/arch/arm/kernel/tcm.c b/arch/arm/kernel/tcm.c
index d3a85f01b328..f59927bcfbce 100644
--- a/arch/arm/kernel/tcm.c
+++ b/arch/arm/kernel/tcm.c
@@ -15,7 +15,7 @@
 #include <linux/string.h> /* memcpy */
 #include <asm/cputype.h>
 #include <asm/mach/map.h>
-#include <asm/memory.h>
+#include <asm/page.h>
 #include <asm/system_info.h>
 #include <asm/traps.h>
 #include <asm/tcm.h>
diff --git a/arch/arm/kernel/vmlinux-xip.lds.S b/arch/arm/kernel/vmlinux-xip.lds.S
index 76678732c60d..c16d196b5aad 100644
--- a/arch/arm/kernel/vmlinux-xip.lds.S
+++ b/arch/arm/kernel/vmlinux-xip.lds.S
@@ -12,9 +12,8 @@
 #include <asm/vmlinux.lds.h>
 #include <asm/cache.h>
 #include <asm/thread_info.h>
-#include <asm/memory.h>
-#include <asm/mpu.h>
 #include <asm/page.h>
+#include <asm/mpu.h>
 
 OUTPUT_ARCH(arm)
 ENTRY(stext)
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index aa12b65a7fd6..bd9127c4b451 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -12,9 +12,8 @@
 #include <asm/vmlinux.lds.h>
 #include <asm/cache.h>
 #include <asm/thread_info.h>
-#include <asm/memory.h>
-#include <asm/mpu.h>
 #include <asm/page.h>
+#include <asm/mpu.h>
 
 OUTPUT_ARCH(arm)
 ENTRY(stext)