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Commit 6f284a2c authored by Franck Bui-Huu's avatar Franck Bui-Huu Committed by Ralf Baechle
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[MIPS] FLATMEM: introduce PHYS_OFFSET. 



The old code was assuming that min_low_pfn was always 0. This
means that platforms having a big hole at their memory start
paid the price of wasting some memory for the allocation of
unused entries in mem_map[].

This patch prevents this waste.

It introduces PHYS_OFFSET define which is the start of the
physical memory and uses it wherever needed. Specially when
converting physical/virtual addresses into virtual/physical
ones.

Currently all platforms defines PHYS_OFFSET to 0.

Signed-off-by: default avatarFranck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent db84dc61

arch/mips/kernel/setup.c

+8 −4
Original line number Diff line number Diff line
@@ -315,13 +315,17 @@ static void __init bootmem_init(void) 


	if (min_low_pfn >= max_low_pfn)

		panic("Incorrect memory mapping !!!");

	if (min_low_pfn > 0) {

	if (min_low_pfn > ARCH_PFN_OFFSET) {

		printk(KERN_INFO

		       "Wasting %lu bytes for tracking %lu unused pages\n",

		       min_low_pfn * sizeof(struct page),

		       min_low_pfn);

		min_low_pfn = 0;

		       (min_low_pfn - ARCH_PFN_OFFSET) * sizeof(struct page),

		       min_low_pfn - ARCH_PFN_OFFSET);

	} else if (min_low_pfn < ARCH_PFN_OFFSET) {

		printk(KERN_INFO

		       "%lu free pages won't be used\n",

		       ARCH_PFN_OFFSET - min_low_pfn);

	}

	min_low_pfn = ARCH_PFN_OFFSET;



	/*

	 * Determine low and high memory ranges

include/asm-mips/io.h

+2 −2
Original line number Diff line number Diff line
@@ -115,7 +115,7 @@ static inline void set_io_port_base(unsigned long base) 
 */

static inline unsigned long virt_to_phys(volatile const void *address)

{

	return (unsigned long)address - PAGE_OFFSET;

	return (unsigned long)address - PAGE_OFFSET + PHYS_OFFSET;

}



/*
@@ -132,7 +132,7 @@ static inline unsigned long virt_to_phys(volatile const void *address) 
 */

static inline void * phys_to_virt(unsigned long address)

{

	return (void *)(address + PAGE_OFFSET);

	return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);

}



/*

include/asm-mips/page.h

+21 −4
Original line number Diff line number Diff line
@@ -34,6 +34,20 @@ 


#ifndef __ASSEMBLY__



/*

 * This gives the physical RAM offset.

 */

#ifndef PHYS_OFFSET

#define PHYS_OFFSET		0UL

#endif



/*

 * It's normally defined only for FLATMEM config but it's

 * used in our early mem init code for all memory models.

 * So always define it.

 */

#define ARCH_PFN_OFFSET		PFN_UP(PHYS_OFFSET)



#include <linux/pfn.h>

#include <asm/io.h>
@@ -132,20 +146,23 @@ typedef struct { unsigned long pgprot; } pgprot_t; 
/* to align the pointer to the (next) page boundary */

#define PAGE_ALIGN(addr)	(((addr) + PAGE_SIZE - 1) & PAGE_MASK)



/*

 * __pa()/__va() should be used only during mem init.

 */

#if defined(CONFIG_64BIT) && !defined(CONFIG_BUILD_ELF64)

#define __pa_page_offset(x)	((unsigned long)(x) < CKSEG0 ? PAGE_OFFSET : CKSEG0)

#else

#define __pa_page_offset(x)	PAGE_OFFSET

#endif

#define __pa(x)			((unsigned long)(x) - __pa_page_offset(x))

#define __pa(x)		((unsigned long)(x) - __pa_page_offset(x) + PHYS_OFFSET)

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

#define __pa_symbol(x)	__pa(RELOC_HIDE((unsigned long)(x),0))

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



#define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)



#ifdef CONFIG_FLATMEM



#define pfn_valid(pfn)		((pfn) < max_mapnr)

#define pfn_valid(pfn)		((pfn) >= ARCH_PFN_OFFSET && (pfn) < max_mapnr)



#elif defined(CONFIG_SPARSEMEM)