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[MIPS] FLATMEM: introduce PHYS_OFFSET.

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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: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Franck Bui-Huu 2007-01-10 09:44:05 +01:00 committed by Ralf Baechle
parent db84dc6155
commit 6f284a2ce7
3 changed files with 31 additions and 10 deletions
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12
arch/mips/kernel/setup.c
View file

@ -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

4
include/asm-mips/io.h
View file

@ -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);
}
/*

25
include/asm-mips/page.h
View file

@ -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_symbol(x) __pa(RELOC_HIDE((unsigned long)(x),0))
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
#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 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)