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>
diff --git a/include/asm-x86/e820_32.h b/include/asm-x86/e820_32.h
index e2faf5f..f1da7eb 100644
--- a/include/asm-x86/e820_32.h
+++ b/include/asm-x86/e820_32.h
@@ -19,12 +19,15 @@
#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);