Commit a9ff6961 authored by Linus Walleij's avatar Linus Walleij
Browse files

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: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 2d78057f

arch/arm/common/sharpsl_param.c

+1 −1
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ 
#include <linux/module.h>

#include <linux/string.h>

#include <asm/mach/sharpsl_param.h>

#include <asm/memory.h>

#include <asm/page.h>



/*

 * Certain hardware parameters determined at the time of device manufacture,

arch/arm/include/asm/delay.h

+1 −1
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ 
#ifndef __ASM_ARM_DELAY_H

#define __ASM_ARM_DELAY_H



#include <asm/memory.h>

#include <asm/page.h>

#include <asm/param.h>	/* HZ */



/*

arch/arm/include/asm/io.h

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 
#include <linux/string.h>

#include <linux/types.h>

#include <asm/byteorder.h>

#include <asm/memory.h>

#include <asm/page.h>

#include <asm-generic/pci_iomap.h>



/*

arch/arm/include/asm/memory.h

+12 −5
Original line number Diff line number Diff line
@@ -5,11 +5,16 @@ 
 *  Copyright (C) 2000-2002 Russell King

 *  modification for nommu, Hyok S. Choi, 2004

 *

 *  Note: this file should not be included by non-asm/.h files

 *  Note: this file should not be included explicitly, include <asm/page.h>

 *  to get access to these definitions.

 */

#ifndef __ASM_ARM_MEMORY_H

#define __ASM_ARM_MEMORY_H



#ifndef _ASMARM_PAGE_H

#error "Do not include <asm/memory.h> directly"

#endif



#include <linux/compiler.h>

#include <linux/const.h>

#include <linux/types.h>
@@ -288,10 +293,12 @@ static inline unsigned long __phys_to_virt(phys_addr_t x) 


#endif



#define virt_to_pfn(kaddr) \

	((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \

	 PHYS_PFN_OFFSET)



static inline unsigned long virt_to_pfn(const void *p)

{

	unsigned long kaddr = (unsigned long)p;

	return (((kaddr - PAGE_OFFSET) >> PAGE_SHIFT) +

		PHYS_PFN_OFFSET);

}

#define __pa_symbol_nodebug(x)	__virt_to_phys_nodebug((x))



#ifdef CONFIG_DEBUG_VIRTUAL

arch/arm/include/asm/page.h

+2 −2
Original line number Diff line number Diff line
@@ -161,10 +161,10 @@ extern int pfn_valid(unsigned long); 
#define pfn_valid pfn_valid

#endif



#include <asm/memory.h>



#endif /* !__ASSEMBLY__ */



#include <asm/memory.h>



#define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_TSK_EXEC



#include <asm-generic/getorder.h>