linux/include/asm-x86/e820_32.h
Yinghai Lu 093af8d7f0 x86_32: trim memory by updating e820
when MTRRs are not covering the whole e820 table, we need to trim the
RAM and need to update e820.

reuse some code on 64-bit as well.

here need to add early_get_cap and use it in early_cpu_detect, and move
mtrr_bp_init early.

The code successfully trimmed the memory map on Justin's system:

from:

 [    0.000000]  BIOS-e820: 0000000100000000 - 000000022c000000 (usable)

to:

 [    0.000000]   modified: 0000000100000000 - 0000000228000000 (usable)
 [    0.000000]   modified: 0000000228000000 - 000000022c000000 (reserved)

According to Justin it makes quite a difference:

|  When I boot the box without any trimming it acts like a 286 or 386,
|  takes about 10 minutes to boot (using raptor disks).

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:32 +01:00

49 lines
1.4 KiB
C

/*
* structures and definitions for the int 15, ax=e820 memory map
* scheme.
*
* In a nutshell, arch/i386/boot/setup.S populates a scratch table
* in the empty_zero_block that contains a list of usable address/size
* duples. In arch/i386/kernel/setup.c, this information is
* transferred into the e820map, and in arch/i386/mm/init.c, that
* new information is used to mark pages reserved or not.
*
*/
#ifndef __E820_HEADER
#define __E820_HEADER
#include <linux/ioport.h>
#define HIGH_MEMORY (1024*1024)
#ifndef __ASSEMBLY__
extern struct e820map e820;
extern void update_e820(void);
extern int e820_all_mapped(unsigned long start, unsigned long end,
unsigned type);
extern int e820_any_mapped(u64 start, u64 end, unsigned type);
extern void find_max_pfn(void);
extern void register_bootmem_low_pages(unsigned long max_low_pfn);
extern void add_memory_region(unsigned long long start,
unsigned long long size, int type);
extern void e820_register_memory(void);
extern void limit_regions(unsigned long long size);
extern void print_memory_map(char *who);
extern void init_iomem_resources(struct resource *code_resource,
struct resource *data_resource,
struct resource *bss_resource);
#if defined(CONFIG_PM) && defined(CONFIG_HIBERNATION)
extern void e820_mark_nosave_regions(void);
#else
static inline void e820_mark_nosave_regions(void)
{
}
#endif
#endif/*!__ASSEMBLY__*/
#endif/*__E820_HEADER*/