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/include/asm/acpi.h

@@ -118,7 +118,7 @@ extern void acpi_restore_state_mem(void);
 extern unsigned long acpi_wakeup_address;
 
 /* early initialization routine */
-extern void acpi_reserve_bootmem(void);
+extern void acpi_reserve_wakeup_memory(void);
 
 /*
  * Check if the CPU can handle C2 and deeper

arch/x86/kernel/acpi/sleep.c

@@ -119,29 +119,32 @@ void acpi_restore_state_mem(void)
 
 
 /**
- * acpi_reserve_bootmem - do _very_ early ACPI initialisation
+ * acpi_reserve_wakeup_memory - do _very_ early ACPI initialisation
  *
  * We allocate a page from the first 1MB of memory for the wakeup
  * routine for when we come back from a sleep state. The
  * runtime allocator allows specification of <16MB pages, but not
  * <1MB pages.
  */
-void __init acpi_reserve_bootmem(void)
+void __init acpi_reserve_wakeup_memory(void)
 {
+	unsigned long mem;
+
 	if ((&wakeup_code_end - &wakeup_code_start) > WAKEUP_SIZE) {
 		printk(KERN_ERR
 		       "ACPI: Wakeup code way too big, S3 disabled.\n");
 		return;
 	}
 
-	acpi_realmode = (unsigned long)alloc_bootmem_low(WAKEUP_SIZE);
+	mem = find_e820_area(0, 1<<20, WAKEUP_SIZE, PAGE_SIZE);
 
-	if (!acpi_realmode) {
+	if (mem == -1L) {
 		printk(KERN_ERR "ACPI: Cannot allocate lowmem, S3 disabled.\n");
 		return;
 	}
-
-	acpi_wakeup_address = virt_to_phys((void *)acpi_realmode);
+	acpi_realmode = (unsigned long) phys_to_virt(mem);
+	acpi_wakeup_address = mem;
+	reserve_early(mem, mem + WAKEUP_SIZE, "ACPI WAKEUP");
 }
 
 

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:
 	 */