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>

1 files changed, 14 insertions, 3 deletions

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);
 	}
 }