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>

10 files changed, 98 insertions, 65 deletions

diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h
index 3ab0537872fb..476b574de99e 100644
--- a/arch/x86/include/asm/e820.h
+++ b/arch/x86/include/asm/e820.h
@@ -10,8 +10,8 @@
 #include <uapi/asm/e820.h>
 #ifndef __ASSEMBLY__
 /* see comment in arch/x86/kernel/e820.c */
-extern struct e820map e820;
-extern struct e820map e820_saved;
+extern struct e820map *e820;
+extern struct e820map *e820_saved;
 
 extern unsigned long pci_mem_start;
 extern int e820_any_mapped(u64 start, u64 end, unsigned type);
@@ -53,6 +53,8 @@ extern void e820_reserve_resources_late(void);
 extern void setup_memory_map(void);
 extern char *default_machine_specific_memory_setup(void);
 
+extern void e820_reallocate_tables(void);
+
 /*
  * Returns true iff the specified range [s,e) is completely contained inside
  * the ISA region.
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)
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index de7501edb21c..18bb3a639197 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/arch/x86/kernel/early-quirks.c
@@ -555,7 +555,7 @@ intel_graphics_stolen(int num, int slot, int func,
 
         /* Mark this space as reserved */
         e820_add_region(base, size, E820_RESERVED);
-        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+        sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
 }
 
 static void __init intel_graphics_quirks(int num, int slot, int func)
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index f2356bda2b05..3407b148c240 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -99,14 +99,14 @@ static int setup_e820_entries(struct boot_params *params)
 {
         unsigned int nr_e820_entries;
 
-        nr_e820_entries = e820_saved.nr_map;
+        nr_e820_entries = e820_saved->nr_map;
 
         /* TODO: Pass entries more than E820MAX in bootparams setup data */
         if (nr_e820_entries > E820MAX)
                 nr_e820_entries = E820MAX;
 
         params->e820_entries = nr_e820_entries;
-        memcpy(&params->e820_map, &e820_saved.map,
+        memcpy(&params->e820_map, &e820_saved->map,
                nr_e820_entries * sizeof(struct e820entry));
 
         return 0;
diff --git a/arch/x86/kernel/resource.c b/arch/x86/kernel/resource.c
index 80eab01c1a68..2408c1603438 100644
--- a/arch/x86/kernel/resource.c
+++ b/arch/x86/kernel/resource.c
@@ -27,8 +27,8 @@ static void remove_e820_regions(struct resource *avail)
         int i;
         struct e820entry *entry;
 
-        for (i = 0; i < e820.nr_map; i++) {
-                entry = &e820.map[i];
+        for (i = 0; i < e820->nr_map; i++) {
+                entry = &e820->map[i];
 
                 resource_clip(avail, entry->addr,
                               entry->addr + entry->size - 1);
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 0fa60f5f5a16..cc43d660c990 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -458,8 +458,8 @@ static void __init e820_reserve_setup_data(void)
                 early_memunmap(data, sizeof(*data));
         }
 
-        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
-        memcpy(&e820_saved, &e820, sizeof(struct e820map));
+        sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
+        memcpy(e820_saved, e820, sizeof(struct e820map));
         printk(KERN_INFO "extended physical RAM map:\n");
         e820_print_map("reserve setup_data");
 }
@@ -763,7 +763,7 @@ static void __init trim_bios_range(void)
          */
         e820_remove_range(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_RAM, 1);
 
-        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+        sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
 }
 
 /* called before trim_bios_range() to spare extra sanitize */
@@ -1032,7 +1032,7 @@ void __init setup_arch(char **cmdline_p)
         if (ppro_with_ram_bug()) {
                 e820_update_range(0x70000000ULL, 0x40000ULL, E820_RAM,
                                   E820_RESERVED);
-                sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+                sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
                 printk(KERN_INFO "fixed physical RAM map:\n");
                 e820_print_map("bad_ppro");
         }
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index 654f6c66fe45..8402907825b0 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -188,12 +188,12 @@ static int tboot_setup_sleep(void)
 
         tboot->num_mac_regions = 0;
 
-        for (i = 0; i < e820.nr_map; i++) {
-                if ((e820.map[i].type != E820_RAM)
-                 && (e820.map[i].type != E820_RESERVED_KERN))
+        for (i = 0; i < e820->nr_map; i++) {
+                if ((e820->map[i].type != E820_RAM)
+                 && (e820->map[i].type != E820_RESERVED_KERN))
                         continue;
 
-                add_mac_region(e820.map[i].addr, e820.map[i].size);
+                add_mac_region(e820->map[i].addr, e820->map[i].size);
         }
 
         tboot->acpi_sinfo.kernel_s3_resume_vector =
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index d28a2d741f9e..167deae767cb 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -701,6 +701,8 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
 
 void free_initmem(void)
 {
+        /* e820_reallocate_tables(); - disabled for now */
+
         free_init_pages("unused kernel",
                         (unsigned long)(&__init_begin),
                         (unsigned long)(&__init_end));
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 1fbb408e2e72..2e3433444b65 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -166,7 +166,7 @@ static void __init do_add_efi_memmap(void)
                 }
                 e820_add_region(start, size, e820_type);
         }
-        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+        sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
 }
 
 int __init efi_memblock_x86_reserve_range(void)
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 176425233e4d..f8960fca0827 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -861,7 +861,7 @@ char * __init xen_memory_setup(void)
         e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
                         E820_RESERVED);
 
-        sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+        sanitize_e820_map(e820->map, ARRAY_SIZE(e820->map), &e820->nr_map);
 
         /*
          * Check whether the kernel itself conflicts with the target E820 map.