[PATCH] alpha: initrd vs. "mem=" fix

As the aboot always puts initrd image near the top of physical memory,
initrd is not accessible if we limit memory size with "mem=" argument.
Fixed by moving the image to the "low" memory if needed.

Also, some of these routines will be used by marvel (in non-NUMA config)
and up1500.

Ivan.

arch/alpha/kernel/setup.c

@@ -251,6 +251,27 @@ get_mem_size_limit(char *s)
         return end >> PAGE_SHIFT; /* Return the PFN of the limit. */
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void * __init
+move_initrd(unsigned long mem_limit)
+{
+	void *start;
+	unsigned long size;
+
+	size = initrd_end - initrd_start;
+	start = __alloc_bootmem(size, PAGE_SIZE, 0);
+	if (!start || __pa(start) + size > mem_limit) {
+		initrd_start = initrd_end = 0;
+		return NULL;
+	}
+	memmove(start, (void *)initrd_start, size);
+	initrd_start = (unsigned long)start;
+	initrd_end = initrd_start + size;
+	printk("initrd moved to %p\n", start);
+	return start;
+}
+#endif
+
 #ifndef CONFIG_DISCONTIGMEM
 static void __init
 setup_memory(void *kernel_end)
@@ -379,11 +400,11 @@ setup_memory(void *kernel_end)
 		       (void *) initrd_start, INITRD_SIZE);
 
 		if ((void *)initrd_end > phys_to_virt(PFN_PHYS(max_low_pfn))) {
-			printk("initrd extends beyond end of memory "
-			       "(0x%08lx > 0x%p)\ndisabling initrd\n",
-			       initrd_end,
-			       phys_to_virt(PFN_PHYS(max_low_pfn)));
-			initrd_start = initrd_end = 0;
+			if (!move_initrd(PFN_PHYS(max_low_pfn)))
+				printk("initrd extends beyond end of memory "
+				       "(0x%08lx > 0x%p)\ndisabling initrd\n",
+				       initrd_end,
+				       phys_to_virt(PFN_PHYS(max_low_pfn)));
 		} else {
 			reserve_bootmem(virt_to_phys((void *)initrd_start),
 					INITRD_SIZE);

arch/alpha/mm/init.c

@@ -357,18 +357,23 @@ mem_init(void)
 #endif /* CONFIG_DISCONTIGMEM */
 
 void
-free_initmem (void)
+free_reserved_mem(void *start, void *end)
 {
-	extern char __init_begin, __init_end;
-	unsigned long addr;
-
-	addr = (unsigned long)(&__init_begin);
-	for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(addr));
-		set_page_count(virt_to_page(addr), 1);
-		free_page(addr);
+	void *__start = start;
+	for (; __start < end; __start += PAGE_SIZE) {
+		ClearPageReserved(virt_to_page(__start));
+		set_page_count(virt_to_page(__start), 1);
+		free_page((long)__start);
 		totalram_pages++;
 	}
+}
+
+void
+free_initmem(void)
+{
+	extern char __init_begin, __init_end;
+
+	free_reserved_mem(&__init_begin, &__init_end);
 	printk ("Freeing unused kernel memory: %ldk freed\n",
 		(&__init_end - &__init_begin) >> 10);
 }
@@ -377,13 +382,7 @@ free_initmem (void)
 void
 free_initrd_mem(unsigned long start, unsigned long end)
 {
-	unsigned long __start = start;
-	for (; start < end; start += PAGE_SIZE) {
-		ClearPageReserved(virt_to_page(start));
-		set_page_count(virt_to_page(start), 1);
-		free_page(start);
-		totalram_pages++;
-	}
-	printk ("Freeing initrd memory: %ldk freed\n", (end - __start) >> 10);
+	free_reserved_mem((void *)start, (void *)end);
+	printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 }
 #endif

arch/alpha/mm/numa.c

@@ -249,16 +249,18 @@ setup_memory(void *kernel_end)
 #ifdef CONFIG_BLK_DEV_INITRD
 	initrd_start = INITRD_START;
 	if (initrd_start) {
+		extern void *move_initrd(unsigned long);
+
 		initrd_end = initrd_start+INITRD_SIZE;
 		printk("Initial ramdisk at: 0x%p (%lu bytes)\n",
 		       (void *) initrd_start, INITRD_SIZE);
 
 		if ((void *)initrd_end > phys_to_virt(PFN_PHYS(max_low_pfn))) {
-			printk("initrd extends beyond end of memory "
-			       "(0x%08lx > 0x%p)\ndisabling initrd\n",
-			       initrd_end,
-			       phys_to_virt(PFN_PHYS(max_low_pfn)));
-			initrd_start = initrd_end = 0;
+			if (!move_initrd(PFN_PHYS(max_low_pfn)))
+				printk("initrd extends beyond end of memory "
+				       "(0x%08lx > 0x%p)\ndisabling initrd\n",
+				       initrd_end,
+				       phys_to_virt(PFN_PHYS(max_low_pfn)));
 		} else {
 			reserve_bootmem_node(NODE_DATA(KVADDR_TO_NID(initrd_start)),
 					     virt_to_phys((void *)initrd_start),