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Commit 7d74275d authored by Alexander Duyck's avatar Alexander Duyck Committed by H. Peter Anvin
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x86: Make it so that __pa_symbol can only process kernel symbols on x86_64 



I submitted an earlier patch that make __phys_addr an inline.  This obviously
results in an increase in the code size.  One step I can take to reduce that
is to make it so that the __pa_symbol call does a direct translation for
kernel addresses instead of covering all of virtual memory.

On my system this reduced the size for __pa_symbol from 5 instructions
totalling 30 bytes to 3 instructions totalling 16 bytes.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Link: http://lkml.kernel.org/r/20121116215356.8521.92472.stgit@ahduyck-cp1.jf.intel.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 0bdf525f

arch/x86/include/asm/page.h

+2 −1
Original line number Diff line number Diff line
@@ -44,7 +44,8 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr, 
 * case properly. Once all supported versions of gcc understand it, we can

 * remove this Voodoo magic stuff. (i.e. once gcc3.x is deprecated)

 */

#define __pa_symbol(x)	__pa(__phys_reloc_hide((unsigned long)(x)))

#define __pa_symbol(x) \

	__phys_addr_symbol(__phys_reloc_hide((unsigned long)(x)))



#define __va(x)			((void *)((unsigned long)(x)+PAGE_OFFSET))

arch/x86/include/asm/page_32.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ extern unsigned long __phys_addr(unsigned long); 
#else

#define __phys_addr(x)		__phys_addr_nodebug(x)

#endif

#define __phys_addr_symbol(x)	__phys_addr(x)

#define __phys_reloc_hide(x)	RELOC_HIDE((x), 0)



#ifdef CONFIG_FLATMEM

arch/x86/include/asm/page_64.h

+3 −0
Original line number Diff line number Diff line
@@ -21,8 +21,11 @@ static inline unsigned long __phys_addr_nodebug(unsigned long x) 


#ifdef CONFIG_DEBUG_VIRTUAL

extern unsigned long __phys_addr(unsigned long);

extern unsigned long __phys_addr_symbol(unsigned long);

#else

#define __phys_addr(x)		__phys_addr_nodebug(x)

#define __phys_addr_symbol(x) \

	((unsigned long)(x) - __START_KERNEL_map + phys_base)

#endif



#define __phys_reloc_hide(x)	(x)

arch/x86/mm/physaddr.c

+11 −0
Original line number Diff line number Diff line
@@ -28,6 +28,17 @@ unsigned long __phys_addr(unsigned long x) 
	return x;

}

EXPORT_SYMBOL(__phys_addr);



unsigned long __phys_addr_symbol(unsigned long x)

{

	unsigned long y = x - __START_KERNEL_map;



	/* only check upper bounds since lower bounds will trigger carry */

	VIRTUAL_BUG_ON(y >= KERNEL_IMAGE_SIZE);



	return y + phys_base;

}

EXPORT_SYMBOL(__phys_addr_symbol);

#endif



bool __virt_addr_valid(unsigned long x)