[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
diff --git a/include/asm-mips/io.h b/include/asm-mips/io.h
index d77b657..67f0810 100644
--- a/include/asm-mips/io.h
+++ b/include/asm-mips/io.h
@@ -115,7 +115,7 @@
*/
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 void * phys_to_virt(unsigned long address)
{
- return (void *)(address + PAGE_OFFSET);
+ return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);
}
/*
diff --git a/include/asm-mips/page.h b/include/asm-mips/page.h
index 2f9e1a9..d3fbd83 100644
--- a/include/asm-mips/page.h
+++ b/include/asm-mips/page.h
@@ -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 @@
/* 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)