x86: e820: Remove conditional early mapping in parse_e820_ext

This patch ensures that the memory passed from parse_setup_data() is
large enough to cover the complete data structure. That means that the
conditional mapping in parse_e820_ext() can go.

While here, I also attempt not to map two pages if the address is not
aligned to a page boundary.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Cc: sodaville@linutronix.de
Cc: devicetree-discuss@lists.ozlabs.org
LKML-Reference: <1298405266-1624-2-git-send-email-bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 15 insertions, 10 deletions

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 294f26da0c0c..5fad62684651 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -667,21 +667,15 @@ __init void e820_setup_gap(void)
  * boot_params.e820_map, others are passed via SETUP_E820_EXT node of
  * linked list of struct setup_data, which is parsed here.
  */
-void __init parse_e820_ext(struct setup_data *sdata, unsigned long pa_data)
+void __init parse_e820_ext(struct setup_data *sdata)
 {
-        u32 map_len;
         int entries;
         struct e820entry *extmap;
 
         entries = sdata->len / sizeof(struct e820entry);
-        map_len = sdata->len + sizeof(struct setup_data);
-        if (map_len > PAGE_SIZE)
-                sdata = early_ioremap(pa_data, map_len);
         extmap = (struct e820entry *)(sdata->data);
         __append_e820_map(extmap, entries);
         sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
-        if (map_len > PAGE_SIZE)
-                early_iounmap(sdata, map_len);
         printk(KERN_INFO "extended physical RAM map:\n");
         e820_print_map("extended");
 }
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index ca2f10622a79..9521483ce58c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -429,16 +429,27 @@ static void __init parse_setup_data(void)
                 return;
         pa_data = boot_params.hdr.setup_data;
         while (pa_data) {
-                data = early_memremap(pa_data, PAGE_SIZE);
+                u32 data_len, map_len;
+
+                map_len = max(PAGE_SIZE - (pa_data & ~PAGE_MASK),
+                              (u64)sizeof(struct setup_data));
+                data = early_memremap(pa_data, map_len);
+                data_len = data->len + sizeof(struct setup_data);
+                if (data_len > map_len) {
+                        early_iounmap(data, map_len);
+                        data = early_memremap(pa_data, data_len);
+                        map_len = data_len;
+                }
+
                 switch (data->type) {
                 case SETUP_E820_EXT:
-                        parse_e820_ext(data, pa_data);
+                        parse_e820_ext(data);
                         break;
                 default:
                         break;
                 }
                 pa_data = data->next;
-                early_iounmap(data, PAGE_SIZE);
+                early_iounmap(data, map_len);
         }
 }