x86/e820: Prepare e280 code for switch to dynamic storage

This patch turns e820 and e820_saved into pointers to e820 tables,
of the same size as before.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20160917213927.1787-2-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 77 insertions, 48 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 4d3dd9a713c7..585000c98d3e 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -40,8 +40,10 @@
  * user can e.g. boot the original kernel with mem=1G while still booting the
  * next kernel with full memory.
  */
-struct e820map e820;
-struct e820map e820_saved;
+static struct e820map initial_e820;
+static struct e820map initial_e820_saved;
+struct e820map *e820 = &initial_e820;
+struct e820map *e820_saved = &initial_e820_saved;
 
 /* For PCI or other memory-mapped resources */
 unsigned long pci_mem_start = 0xaeedbabe;
@@ -58,8 +60,8 @@ e820_any_mapped(u64 start, u64 end, unsigned type)
 {
 	int i;
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 
 		if (type && ei->type != type)
 			continue;
@@ -81,8 +83,8 @@ int __init e820_all_mapped(u64 start, u64 end, unsigned type)
 {
 	int i;
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 
 		if (type && ei->type != type)
 			continue;
@@ -128,7 +130,7 @@ static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size,
 
 void __init e820_add_region(u64 start, u64 size, int type)
 {
-	__e820_add_region(&e820, start, size, type);
+	__e820_add_region(e820, start, size, type);
 }
 
 static void __init e820_print_type(u32 type)
@@ -164,12 +166,12 @@ void __init e820_print_map(char *who)
 {
 	int i;
 
-	for (i = 0; i < e820.nr_map; i++) {
+	for (i = 0; i < e820->nr_map; i++) {
 		printk(KERN_INFO "%s: [mem %#018Lx-%#018Lx] ", who,
-		       (unsigned long long) e820.map[i].addr,
+		       (unsigned long long) e820->map[i].addr,
 		       (unsigned long long)
-		       (e820.map[i].addr + e820.map[i].size - 1));
-		e820_print_type(e820.map[i].type);
+		       (e820->map[i].addr + e820->map[i].size - 1));
+		e820_print_type(e820->map[i].type);
 		printk(KERN_CONT "\n");
 	}
 }
@@ -493,13 +495,13 @@ static u64 __init __e820_update_range(struct e820map *e820x, u64 start,
 u64 __init e820_update_range(u64 start, u64 size, unsigned old_type,
 			     unsigned new_type)
 {
-	return __e820_update_range(&e820, start, size, old_type, new_type);
+	return __e820_update_range(e820, start, size, old_type, new_type);
 }
 
 static u64 __init e820_update_range_saved(u64 start, u64 size,
 					  unsigned old_type, unsigned new_type)
 {
-	return __e820_update_range(&e820_saved, start, size, old_type,
+	return __e820_update_range(e820_saved, start, size, old_type,
 				     new_type);
 }
 
@@ -521,8 +523,8 @@ u64 __init e820_remove_range(u64 start, u64 size, unsigned old_type,
 		e820_print_type(old_type);
 	printk(KERN_CONT "\n");
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 		u64 final_start, final_end;
 		u64 ei_end;
 
@@ -566,15 +568,15 @@ u64 __init e820_remove_range(u64 start, u64 size, unsigned old_type,
 
 void __init update_e820(void)
 {
-	if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map))
+	if (sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map))
 		return;
 	printk(KERN_INFO "e820: modified physical RAM map:\n");
 	e820_print_map("modified");
 }
 static void __init update_e820_saved(void)
 {
-	sanitize_e820_map(e820_saved.map, ARRAY_SIZE(e820_saved.map),
-				&e820_saved.nr_map);
+	sanitize_e820_map(e820_saved->map, ARRAY_SIZE(e820_saved->map),
+				&e820_saved->nr_map);
 }
 #define MAX_GAP_END 0x100000000ull
 /*
@@ -584,14 +586,14 @@ __init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
 		unsigned long start_addr, unsigned long long end_addr)
 {
 	unsigned long long last;
-	int i = e820.nr_map;
+	int i = e820->nr_map;
 	int found = 0;
 
 	last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END;
 
 	while (--i >= 0) {
-		unsigned long long start = e820.map[i].addr;
-		unsigned long long end = start + e820.map[i].size;
+		unsigned long long start = e820->map[i].addr;
+		unsigned long long end = start + e820->map[i].size;
 
 		if (end < start_addr)
 			continue;
@@ -649,6 +651,33 @@ __init void e820_setup_gap(void)
 	       gapstart, gapstart + gapsize - 1);
 }
 
+/*
+ * Called late during init, in free_initmem().
+ *
+ * Initial e820 and e820_saved are largish __initdata arrays.
+ * Copy them to (usually much smaller) dynamically allocated area.
+ * This is done after all tweaks we ever do to them:
+ * all functions which modify them are __init functions,
+ * they won't exist after this point.
+ */
+__init void e820_reallocate_tables(void)
+{
+	struct e820map *n;
+	int size;
+
+	size = offsetof(struct e820map, map) + sizeof(struct e820entry) * e820->nr_map;
+	n = kmalloc(size, GFP_KERNEL);
+	BUG_ON(!n);
+	memcpy(n, e820, size);
+	e820 = n;
+
+	size = offsetof(struct e820map, map) + sizeof(struct e820entry) * e820_saved->nr_map;
+	n = kmalloc(size, GFP_KERNEL);
+	BUG_ON(!n);
+	memcpy(n, e820_saved, size);
+	e820_saved = n;
+}
+
 /**
  * Because of the size limitation of struct boot_params, only first
  * 128 E820 memory entries are passed to kernel via
@@ -665,7 +694,7 @@ void __init parse_e820_ext(u64 phys_addr, u32 data_len)
 	entries = sdata->len / sizeof(struct e820entry);
 	extmap = (struct e820entry *)(sdata->data);
 	__append_e820_map(extmap, entries);
-	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+	sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
 	early_memunmap(sdata, data_len);
 	printk(KERN_INFO "e820: extended physical RAM map:\n");
 	e820_print_map("extended");
@@ -686,8 +715,8 @@ void __init e820_mark_nosave_regions(unsigned long limit_pfn)
 	int i;
 	unsigned long pfn = 0;
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 
 		if (pfn < PFN_UP(ei->addr))
 			register_nosave_region(pfn, PFN_UP(ei->addr));
@@ -712,8 +741,8 @@ static int __init e820_mark_nvs_memory(void)
 {
 	int i;
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 
 		if (ei->type == E820_NVS)
 			acpi_nvs_register(ei->addr, ei->size);
@@ -760,8 +789,8 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn)
 	unsigned long last_pfn = 0;
 	unsigned long max_arch_pfn = MAX_ARCH_PFN;
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 		unsigned long start_pfn;
 		unsigned long end_pfn;
 
@@ -856,7 +885,7 @@ static int __init parse_memmap_one(char *p)
 		 */
 		saved_max_pfn = e820_end_of_ram_pfn();
 #endif
-		e820.nr_map = 0;
+		e820->nr_map = 0;
 		userdef = 1;
 		return 0;
 	}
@@ -903,8 +932,8 @@ early_param("memmap", parse_memmap_opt);
 void __init finish_e820_parsing(void)
 {
 	if (userdef) {
-		if (sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map),
-					&e820.nr_map) < 0)
+		if (sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map),
+					&e820->nr_map) < 0)
 			early_panic("Invalid user supplied memory map");
 
 		printk(KERN_INFO "e820: user-defined physical RAM map:\n");
@@ -991,35 +1020,35 @@ void __init e820_reserve_resources(void)
 	struct resource *res;
 	u64 end;
 
-	res = alloc_bootmem(sizeof(struct resource) * e820.nr_map);
+	res = alloc_bootmem(sizeof(struct resource) * e820->nr_map);
 	e820_res = res;
-	for (i = 0; i < e820.nr_map; i++) {
-		end = e820.map[i].addr + e820.map[i].size - 1;
+	for (i = 0; i < e820->nr_map; i++) {
+		end = e820->map[i].addr + e820->map[i].size - 1;
 		if (end != (resource_size_t)end) {
 			res++;
 			continue;
 		}
-		res->name = e820_type_to_string(e820.map[i].type);
-		res->start = e820.map[i].addr;
+		res->name = e820_type_to_string(e820->map[i].type);
+		res->start = e820->map[i].addr;
 		res->end = end;
 
-		res->flags = e820_type_to_iomem_type(e820.map[i].type);
-		res->desc = e820_type_to_iores_desc(e820.map[i].type);
+		res->flags = e820_type_to_iomem_type(e820->map[i].type);
+		res->desc = e820_type_to_iores_desc(e820->map[i].type);
 
 		/*
 		 * don't register the region that could be conflicted with
 		 * pci device BAR resource and insert them later in
 		 * pcibios_resource_survey()
 		 */
-		if (do_mark_busy(e820.map[i].type, res)) {
+		if (do_mark_busy(e820->map[i].type, res)) {
 			res->flags |= IORESOURCE_BUSY;
 			insert_resource(&iomem_resource, res);
 		}
 		res++;
 	}
 
-	for (i = 0; i < e820_saved.nr_map; i++) {
-		struct e820entry *entry = &e820_saved.map[i];
+	for (i = 0; i < e820_saved->nr_map; i++) {
+		struct e820entry *entry = &e820_saved->map[i];
 		firmware_map_add_early(entry->addr,
 			entry->addr + entry->size,
 			e820_type_to_string(entry->type));
@@ -1051,7 +1080,7 @@ void __init e820_reserve_resources_late(void)
 	struct resource *res;
 
 	res = e820_res;
-	for (i = 0; i < e820.nr_map; i++) {
+	for (i = 0; i < e820->nr_map; i++) {
 		if (!res->parent && res->end)
 			insert_resource_expand_to_fit(&iomem_resource, res);
 		res++;
@@ -1061,8 +1090,8 @@ void __init e820_reserve_resources_late(void)
 	 * Try to bump up RAM regions to reasonable boundaries to
 	 * avoid stolen RAM:
 	 */
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *entry = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *entry = &e820->map[i];
 		u64 start, end;
 
 		if (entry->type != E820_RAM)
@@ -1110,7 +1139,7 @@ char *__init default_machine_specific_memory_setup(void)
 			who = "BIOS-e801";
 		}
 
-		e820.nr_map = 0;
+		e820->nr_map = 0;
 		e820_add_region(0, LOWMEMSIZE(), E820_RAM);
 		e820_add_region(HIGH_MEMORY, mem_size << 10, E820_RAM);
 	}
@@ -1124,7 +1153,7 @@ void __init setup_memory_map(void)
 	char *who;
 
 	who = x86_init.resources.memory_setup();
-	memcpy(&e820_saved, &e820, sizeof(struct e820map));
+	memcpy(e820_saved, e820, sizeof(struct e820map));
 	printk(KERN_INFO "e820: BIOS-provided physical RAM map:\n");
 	e820_print_map(who);
 }
@@ -1141,8 +1170,8 @@ void __init memblock_x86_fill(void)
 	 */
 	memblock_allow_resize();
 
-	for (i = 0; i < e820.nr_map; i++) {
-		struct e820entry *ei = &e820.map[i];
+	for (i = 0; i < e820->nr_map; i++) {
+		struct e820entry *ei = &e820->map[i];
 
 		end = ei->addr + ei->size;
 		if (end != (resource_size_t)end)