x86: Make sure wakeup trampoline code is below 1MB

Instead of using bootmem, try find_e820_area()/reserve_early(),
and call acpi_reserve_memory() early, to allocate the wakeup
trampoline code area below 1M.

This is more reliable, and it also removes a dependency on
bootmem.

-v2: change function name to acpi_reserve_wakeup_memory(),
     as suggested by Rafael.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: pm list <linux-pm@lists.linux-foundation.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4AFA210B.3020207@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/setup.c

@@ -897,6 +897,13 @@ void __init setup_arch(char **cmdline_p)
 
 	reserve_brk();
 
+#ifdef CONFIG_ACPI_SLEEP
+	/*
+	 * Reserve low memory region for sleep support.
+	 * even before init_memory_mapping
+	 */
+	acpi_reserve_wakeup_memory();
+#endif
 	init_gbpages();
 
 	/* max_pfn_mapped is updated here */
@@ -948,12 +955,6 @@ void __init setup_arch(char **cmdline_p)
 
 	initmem_init(0, max_pfn, acpi, k8);
 
-#ifdef CONFIG_ACPI_SLEEP
-	/*
-	 * Reserve low memory region for sleep support.
-	 */
-	acpi_reserve_bootmem();
-#endif
 	/*
 	 * Find and reserve possible boot-time SMP configuration:
 	 */