[Blackfin] arch: fix bug kernel boot message: memory information is not reasonable

Some of the information in kernel boot message is not reasonable.
http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3846

 - use _rambase as the start of kernel image.
   kernel is in the region [_rambase, _ramstart]
 - count in pages in per-cpu-page list as available memory
 - reserved memory now include: [0 - 4K] for bad pointer catching,
   memory reserved for abnormaly 05000263, memory reserved by kernel itself.
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

arch/blackfin/kernel/setup.c

@@ -238,6 +238,7 @@ void __init setup_arch(char **cmdline_p)
 	memory_end = _ramend - DMA_UNCACHED_REGION;
 
 	_ramstart = (unsigned long)__bss_stop;
+	_rambase = (unsigned long)_stext;
 #ifdef CONFIG_MPU
 	/* Round up to multiple of 4MB.  */
 	memory_start = (_ramstart + 0x3fffff) & ~0x3fffff;

arch/blackfin/mm/init.c

@@ -128,8 +128,8 @@ void __init paging_init(void)
 void __init mem_init(void)
 {
 	unsigned int codek = 0, datak = 0, initk = 0;
+	unsigned int reservedpages = 0, freepages = 0;
 	unsigned long tmp;
-	unsigned int len = _ramend - _rambase;
 	unsigned long start_mem = memory_start;
 	unsigned long end_mem = memory_end;
 
@@ -138,19 +138,36 @@ void __init mem_init(void)
 
 	start_mem = PAGE_ALIGN(start_mem);
 	max_mapnr = num_physpages = MAP_NR(high_memory);
-	printk(KERN_INFO "Physical pages: %lx\n", num_physpages);
+	printk(KERN_INFO "Kernel managed physical pages: %lu\n",
+		num_physpages);
 
 	/* This will put all memory onto the freelists. */
 	totalram_pages = free_all_bootmem();
 
+	reservedpages = 0;
+	for (tmp = 0; tmp < max_mapnr; tmp++)
+		if (PageReserved(pfn_to_page(tmp)))
+			reservedpages++;
+	freepages =  max_mapnr - reservedpages;
+
+	/* do not count in kernel image between _rambase and _ramstart */
+	reservedpages -= (_ramstart - _rambase) >> PAGE_SHIFT;
+#if (defined(CONFIG_BFIN_ICACHE) && ANOMALY_05000263)
+	reservedpages += (_ramend - memory_end - DMA_UNCACHED_REGION) >>
+				PAGE_SHIFT;
+#endif
+
 	codek = (_etext - _stext) >> 10;
-	datak = (__bss_stop - __bss_start) >> 10;
 	initk = (__init_end - __init_begin) >> 10;
+	datak = ((_ramstart - _rambase) >> 10) - codek - initk;
 
-	tmp = nr_free_pages() << PAGE_SHIFT;
 	printk(KERN_INFO
-	     "Memory available: %luk/%uk RAM, (%uk init code, %uk kernel code, %uk data, %uk dma)\n",
-	     tmp >> 10, len >> 10, initk, codek, datak, DMA_UNCACHED_REGION >> 10);
+	     "Memory available: %luk/%luk RAM, "
+		"(%uk init code, %uk kernel code, "
+		"%uk data, %uk dma, %uk reserved)\n",
+		(unsigned long) freepages << (PAGE_SHIFT-10), _ramend >> 10,
+		initk, codek, datak, DMA_UNCACHED_REGION >> 10,
+		(reservedpages << (PAGE_SHIFT-10)));
 
 	/* Initialize the blackfin L1 Memory. */
 	l1sram_init();