[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: 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

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