x86: use early_ioremap in __acpi_map_table

__acpi_map_table() effectively reimplements early_ioremap().  Rather
than have that duplication, just implement it in terms of
early_ioremap().

However, unlike early_ioremap(), __acpi_map_table() just maintains a
single mapping which gets replaced each call, and has no corresponding
unmap function.  Implement this by just removing the previous mapping
each time its called.  Unfortunately, this will leave a stray mapping
at the end.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/acpi.h

@@ -102,9 +102,6 @@ static inline void disable_acpi(void)
 	acpi_noirq = 1;
 }
 
-/* Fixmap pages to reserve for ACPI boot-time tables (see fixmap.h) */
-#define FIX_ACPI_PAGES 4
-
 extern int acpi_gsi_to_irq(u32 gsi, unsigned int *irq);
 
 static inline void acpi_noirq_set(void) { acpi_noirq = 1; }

arch/x86/include/asm/fixmap_32.h

@@ -95,10 +95,6 @@ enum fixed_addresses {
 			(__end_of_permanent_fixed_addresses & 255),
 	FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS*FIX_BTMAPS_SLOTS - 1,
 	FIX_WP_TEST,
-#ifdef CONFIG_ACPI
-	FIX_ACPI_BEGIN,
-	FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
-#endif
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 	FIX_OHCI1394_BASE,
 #endif

arch/x86/include/asm/fixmap_64.h

@@ -50,10 +50,6 @@ enum fixed_addresses {
 	FIX_PARAVIRT_BOOTMAP,
 #endif
 	__end_of_permanent_fixed_addresses,
-#ifdef CONFIG_ACPI
-	FIX_ACPI_BEGIN,
-	FIX_ACPI_END = FIX_ACPI_BEGIN + FIX_ACPI_PAGES - 1,
-#endif
 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 	FIX_OHCI1394_BASE,
 #endif

arch/x86/kernel/acpi/boot.c

@@ -121,8 +121,8 @@ enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_PIC;
  */
 char *__init __acpi_map_table(unsigned long phys, unsigned long size)
 {
-	unsigned long base, offset, mapped_size;
-	int idx;
+	static char *prev_map;
+	static unsigned long prev_size;
 
 	if (!phys || !size)
 		return NULL;
@@ -130,26 +130,13 @@ char *__init __acpi_map_table(unsigned long phys, unsigned long size)
 	if (phys+size <= (max_low_pfn_mapped << PAGE_SHIFT))
 		return __va(phys);
 
-	offset = phys & (PAGE_SIZE - 1);
-	mapped_size = PAGE_SIZE - offset;
-	clear_fixmap(FIX_ACPI_END);
-	set_fixmap(FIX_ACPI_END, phys);
-	base = fix_to_virt(FIX_ACPI_END);
+	if (prev_map)
+		early_iounmap(prev_map, prev_size);
 
-	/*
-	 * Most cases can be covered by the below.
-	 */
-	idx = FIX_ACPI_END;
-	while (mapped_size < size) {
-		if (--idx < FIX_ACPI_BEGIN)
-			return NULL;	/* cannot handle this */
-		phys += PAGE_SIZE;
-		clear_fixmap(idx);
-		set_fixmap(idx, phys);
-		mapped_size += PAGE_SIZE;
-	}
+	prev_size = size;
+	prev_map = early_ioremap(phys, size);
 
-	return ((unsigned char *)base + offset);
+	return prev_map;
 }
 
 #ifdef CONFIG_PCI_MMCONFIG