[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>
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index f352cd9..e1d76b8 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -315,13 +315,17 @@
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