[PATCH] i386: Preserve EFI run time regions with memmap parameter

When using memmap kernel parameter in EFI boot we should also add to memory map
memory regions of runtime services to enable their mapping later.

AK: merged and cleaned up the patch
Signed-off-by: Artiom Myaskouvskey <artiom.myaskouvskey@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>

arch/i386/kernel/e820.c

@@ -742,29 +742,55 @@ void __init print_memory_map(char *who)
 	}
 }
 
-void __init limit_regions(unsigned long long size)
+static __init __always_inline void efi_limit_regions(unsigned long long size)
 {
 	unsigned long long current_addr = 0;
+	efi_memory_desc_t *md, *next_md;
+	void *p, *p1;
+	int i, j;
+
+	j = 0;
+	p1 = memmap.map;
+	for (p = p1, i = 0; p < memmap.map_end; p += memmap.desc_size, i++) {
+		md = p;
+		next_md = p1;
+		current_addr = md->phys_addr +
+			PFN_PHYS(md->num_pages);
+		if (is_available_memory(md)) {
+			if (md->phys_addr >= size) continue;
+			memcpy(next_md, md, memmap.desc_size);
+			if (current_addr >= size) {
+				next_md->num_pages -=
+					PFN_UP(current_addr-size);
+			}
+			p1 += memmap.desc_size;
+			next_md = p1;
+			j++;
+		} else if ((md->attribute & EFI_MEMORY_RUNTIME) ==
+			   EFI_MEMORY_RUNTIME) {
+			/* In order to make runtime services
+			 * available we have to include runtime
+			 * memory regions in memory map */
+			memcpy(next_md, md, memmap.desc_size);
+			p1 += memmap.desc_size;
+			next_md = p1;
+			j++;
+		}
+	}
+	memmap.nr_map = j;
+	memmap.map_end = memmap.map +
+		(memmap.nr_map * memmap.desc_size);
+}
+
+void __init limit_regions(unsigned long long size)
+{
+	unsigned long long current_addr;
 	int i;
 
 	print_memory_map("limit_regions start");
 	if (efi_enabled) {
-		efi_memory_desc_t *md;
-		void *p;
-
-		for (p = memmap.map, i = 0; p < memmap.map_end;
-			p += memmap.desc_size, i++) {
-			md = p;
-			current_addr = md->phys_addr + (md->num_pages << 12);
-			if (md->type == EFI_CONVENTIONAL_MEMORY) {
-				if (current_addr >= size) {
-					md->num_pages -=
-						(((current_addr-size) + PAGE_SIZE-1) >> PAGE_SHIFT);
-					memmap.nr_map = i + 1;
-					return;
-				}
-			}
-		}
+		efi_limit_regions(size);
+		return;
 	}
 	for (i = 0; i < e820.nr_map; i++) {
 		current_addr = e820.map[i].addr + e820.map[i].size;

arch/i386/mm/init.c

@@ -192,8 +192,6 @@ static inline int page_kills_ppro(unsigned long pagenr)
 	return 0;
 }
 
-extern int is_available_memory(efi_memory_desc_t *);
-
 int page_is_ram(unsigned long pagenr)
 {
 	int i;

include/linux/efi.h

@@ -302,6 +302,7 @@ extern void efi_initialize_iomem_resources(struct resource *code_resource,
 					struct resource *data_resource);
 extern unsigned long efi_get_time(void);
 extern int __init efi_set_rtc_mmss(unsigned long nowtime);
+extern int is_available_memory(efi_memory_desc_t * md);
 extern struct efi_memory_map memmap;
 
 /**