[PATCH] swsusp: add architecture special saveable pages support

1. Add architecture specific pages save/restore support.  Next two patches
   will use this to save/restore 'ACPI NVS' pages.

2. Allow reserved pages 'nosave'.  This could avoid save/restore BIOS
   reserved pages.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Nigel Cunningham <nigel@suspend2.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/suspend.h

@@ -71,6 +71,7 @@ struct saved_context;
 void __save_processor_state(struct saved_context *ctxt);
 void __restore_processor_state(struct saved_context *ctxt);
 unsigned long get_safe_page(gfp_t gfp_mask);
+int swsusp_add_arch_pages(unsigned long start, unsigned long end);
 
 /*
  * XXX: We try to keep some more pages free so that I/O operations succeed

kernel/power/power.h

@@ -105,6 +105,10 @@ extern struct bitmap_page *alloc_bitmap(unsigned int nr_bits);
 extern unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap);
 extern void free_all_swap_pages(int swap, struct bitmap_page *bitmap);
 
+extern unsigned int count_special_pages(void);
+extern int save_special_mem(void);
+extern int restore_special_mem(void);
+
 extern int swsusp_check(void);
 extern int swsusp_shrink_memory(void);
 extern void swsusp_free(void);

kernel/power/snapshot.c

@@ -39,6 +39,88 @@ static unsigned int nr_copy_pages;
 static unsigned int nr_meta_pages;
 static unsigned long *buffer;
 
+struct arch_saveable_page {
+	unsigned long start;
+	unsigned long end;
+	char *data;
+	struct arch_saveable_page *next;
+};
+static struct arch_saveable_page *arch_pages;
+
+int swsusp_add_arch_pages(unsigned long start, unsigned long end)
+{
+	struct arch_saveable_page *tmp;
+
+	while (start < end) {
+		tmp = kzalloc(sizeof(struct arch_saveable_page), GFP_KERNEL);
+		if (!tmp)
+			return -ENOMEM;
+		tmp->start = start;
+		tmp->end = ((start >> PAGE_SHIFT) + 1) << PAGE_SHIFT;
+		if (tmp->end > end)
+			tmp->end = end;
+		tmp->next = arch_pages;
+		start = tmp->end;
+		arch_pages = tmp;
+	}
+	return 0;
+}
+
+static unsigned int count_arch_pages(void)
+{
+	unsigned int count = 0;
+	struct arch_saveable_page *tmp = arch_pages;
+	while (tmp) {
+		count++;
+		tmp = tmp->next;
+	}
+	return count;
+}
+
+static int save_arch_mem(void)
+{
+	char *kaddr;
+	struct arch_saveable_page *tmp = arch_pages;
+	int offset;
+
+	pr_debug("swsusp: Saving arch specific memory");
+	while (tmp) {
+		tmp->data = (char *)__get_free_page(GFP_ATOMIC);
+		if (!tmp->data)
+			return -ENOMEM;
+		offset = tmp->start - (tmp->start & PAGE_MASK);
+		/* arch pages might haven't a 'struct page' */
+		kaddr = kmap_atomic_pfn(tmp->start >> PAGE_SHIFT, KM_USER0);
+		memcpy(tmp->data + offset, kaddr + offset,
+			tmp->end - tmp->start);
+		kunmap_atomic(kaddr, KM_USER0);
+
+		tmp = tmp->next;
+	}
+	return 0;
+}
+
+static int restore_arch_mem(void)
+{
+	char *kaddr;
+	struct arch_saveable_page *tmp = arch_pages;
+	int offset;
+
+	while (tmp) {
+		if (!tmp->data)
+			continue;
+		offset = tmp->start - (tmp->start & PAGE_MASK);
+		kaddr = kmap_atomic_pfn(tmp->start >> PAGE_SHIFT, KM_USER0);
+		memcpy(kaddr + offset, tmp->data + offset,
+			tmp->end - tmp->start);
+		kunmap_atomic(kaddr, KM_USER0);
+		free_page((long)tmp->data);
+		tmp->data = NULL;
+		tmp = tmp->next;
+	}
+	return 0;
+}
+
 #ifdef CONFIG_HIGHMEM
 unsigned int count_highmem_pages(void)
 {
@@ -150,8 +232,35 @@ int restore_highmem(void)
 	}
 	return 0;
 }
+#else
+static unsigned int count_highmem_pages(void) {return 0;}
+static int save_highmem(void) {return 0;}
+static int restore_highmem(void) {return 0;}
 #endif
 
+unsigned int count_special_pages(void)
+{
+	return count_arch_pages() + count_highmem_pages();
+}
+
+int save_special_mem(void)
+{
+	int ret;
+	ret = save_arch_mem();
+	if (!ret)
+		ret = save_highmem();
+	return ret;
+}
+
+int restore_special_mem(void)
+{
+	int ret;
+	ret = restore_arch_mem();
+	if (!ret)
+		ret = restore_highmem();
+	return ret;
+}
+
 static int pfn_is_nosave(unsigned long pfn)
 {
 	unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
@@ -177,7 +286,6 @@ static int saveable(struct zone *zone, unsigned long *zone_pfn)
 		return 0;
 
 	page = pfn_to_page(pfn);
-	BUG_ON(PageReserved(page) && PageNosave(page));
 	if (PageNosave(page))
 		return 0;
 	if (PageReserved(page) && pfn_is_nosave(pfn))

kernel/power/swsusp.c

@@ -62,16 +62,6 @@ unsigned long image_size = 500 * 1024 * 1024;
 
 int in_suspend __nosavedata = 0;
 
-#ifdef CONFIG_HIGHMEM
-unsigned int count_highmem_pages(void);
-int save_highmem(void);
-int restore_highmem(void);
-#else
-static int save_highmem(void) { return 0; }
-static int restore_highmem(void) { return 0; }
-static unsigned int count_highmem_pages(void) { return 0; }
-#endif
-
 /**
  *	The following functions are used for tracing the allocated
  *	swap pages, so that they can be freed in case of an error.
@@ -192,7 +182,7 @@ int swsusp_shrink_memory(void)
 
 	printk("Shrinking memory...  ");
 	do {
-		size = 2 * count_highmem_pages();
+		size = 2 * count_special_pages();
 		size += size / 50 + count_data_pages();
 		size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE +
 			PAGES_FOR_IO;
@@ -234,7 +224,7 @@ int swsusp_suspend(void)
 		goto Enable_irqs;
 	}
 
-	if ((error = save_highmem())) {
+	if ((error = save_special_mem())) {
 		printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
 		goto Restore_highmem;
 	}
@@ -245,7 +235,7 @@ int swsusp_suspend(void)
 	/* Restore control flow magically appears here */
 	restore_processor_state();
 Restore_highmem:
-	restore_highmem();
+	restore_special_mem();
 	device_power_up();
 Enable_irqs:
 	local_irq_enable();
@@ -271,7 +261,7 @@ int swsusp_resume(void)
 	 */
 	swsusp_free();
 	restore_processor_state();
-	restore_highmem();
+	restore_special_mem();
 	touch_softlockup_watchdog();
 	device_power_up();
 	local_irq_enable();