acpi/x86: introduce __apci_map_table, v4

to prevent wrongly overwriting fixmap that still want to use.

ACPI used to rely on low mappings being all linearly mapped and
grew a habit: it never really unmapped certain kinds of tables
after use.

This can cause problems - for example the hypothetical case
when some spurious access still references it.

v2: remove prev_map and prev_size in __apci_map_table
v3: let acpi_os_unmap_memory() call early_iounmap too, so remove extral calling to
early_acpi_os_unmap_memory
v4: fix typo in one acpi_get_table_with_size calling
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/ia64/kernel/acpi.c

@@ -199,6 +199,10 @@ char *__init __acpi_map_table(unsigned long phys_addr, unsigned long size)
 	return __va(phys_addr);
 }
 
+char *__init __acpi_unmap_table(unsigned long virt_addr, unsigned long size)
+{
+}
+
 /* --------------------------------------------------------------------------
                             Boot-time Table Parsing
    -------------------------------------------------------------------------- */

arch/x86/kernel/acpi/boot.c

@@ -121,21 +121,18 @@ enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_PIC;
  */
 char *__init __acpi_map_table(unsigned long phys, unsigned long size)
 {
-	static char *prev_map;
-	static unsigned long prev_size;
-
-	if (prev_map) {
-		early_iounmap(prev_map, prev_size);
-		prev_map = NULL;
-	}
 
 	if (!phys || !size)
 		return NULL;
 
-	prev_size = size;
-	prev_map = early_ioremap(phys, size);
+	return early_ioremap(phys, size);
+}
+void __init __acpi_unmap_table(char *map, unsigned long size)
+{
+	if (!map || !size)
+		return;
 
-	return prev_map;
+	early_iounmap(map, size);
 }
 
 #ifdef CONFIG_PCI_MMCONFIG

drivers/acpi/acpica/tbxface.c

@@ -365,7 +365,7 @@ ACPI_EXPORT_SYMBOL(acpi_unload_table_id)
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_get_table
+ * FUNCTION:    acpi_get_table_with_size
  *
  * PARAMETERS:  Signature           - ACPI signature of needed table
  *              Instance            - Which instance (for SSDTs)
@@ -377,8 +377,9 @@ ACPI_EXPORT_SYMBOL(acpi_unload_table_id)
  *
  *****************************************************************************/
 acpi_status
-acpi_get_table(char *signature,
-	       u32 instance, struct acpi_table_header **out_table)
+acpi_get_table_with_size(char *signature,
+	       u32 instance, struct acpi_table_header **out_table,
+	       acpi_size *tbl_size)
 {
        u32 i;
        u32 j;
@@ -408,6 +409,7 @@ acpi_get_table(char *signature,
 		    acpi_tb_verify_table(&acpi_gbl_root_table_list.tables[i]);
 		if (ACPI_SUCCESS(status)) {
 			*out_table = acpi_gbl_root_table_list.tables[i].pointer;
+			*tbl_size = acpi_gbl_root_table_list.tables[i].length;
 		}
 
 		if (!acpi_gbl_permanent_mmap) {
@@ -420,6 +422,15 @@ acpi_get_table(char *signature,
 	return (AE_NOT_FOUND);
 }
 
+acpi_status
+acpi_get_table(char *signature,
+	       u32 instance, struct acpi_table_header **out_table)
+{
+	acpi_size tbl_size;
+
+	return acpi_get_table_with_size(signature,
+		       instance, out_table, &tbl_size);
+}
 ACPI_EXPORT_SYMBOL(acpi_get_table)
 
 /*******************************************************************************

drivers/acpi/bus.c

@@ -694,12 +694,6 @@ void __init acpi_early_init(void)
 	if (!acpi_strict)
 		acpi_gbl_enable_interpreter_slack = TRUE;
 
-	/*
-	 * Doing a zero-sized mapping will clear out the previous
-	 * __acpi_map_table() mapping, if any.
-	 */
-	__acpi_map_table(0, 0);
-
 	acpi_gbl_permanent_mmap = 1;
 
 	status = acpi_reallocate_root_table();

drivers/acpi/osl.c

@@ -274,12 +274,19 @@ EXPORT_SYMBOL_GPL(acpi_os_map_memory);
 
 void acpi_os_unmap_memory(void __iomem * virt, acpi_size size)
 {
-	if (acpi_gbl_permanent_mmap) {
+	if (acpi_gbl_permanent_mmap)
 		iounmap(virt);
-	}
+	else
+		__acpi_unmap_table(virt, size);
 }
 EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
 
+void early_acpi_os_unmap_memory(void __iomem * virt, acpi_size size)
+{
+	if (!acpi_gbl_permanent_mmap)
+		__acpi_unmap_table(virt, size);
+}
+
 #ifdef ACPI_FUTURE_USAGE
 acpi_status
 acpi_os_get_physical_address(void *virt, acpi_physical_address * phys)

drivers/acpi/tables.c

@@ -181,14 +181,15 @@ acpi_table_parse_entries(char *id,
 	struct acpi_subtable_header *entry;
 	unsigned int count = 0;
 	unsigned long table_end;
+	acpi_size tbl_size;
 
 	if (!handler)
 		return -EINVAL;
 
 	if (strncmp(id, ACPI_SIG_MADT, 4) == 0)
-		acpi_get_table(id, acpi_apic_instance, &table_header);
+		acpi_get_table_with_size(id, acpi_apic_instance, &table_header, &tbl_size);
 	else
-		acpi_get_table(id, 0, &table_header);
+		acpi_get_table_with_size(id, 0, &table_header, &tbl_size);
 
 	if (!table_header) {
 		printk(KERN_WARNING PREFIX "%4.4s not present\n", id);
@@ -206,8 +207,10 @@ acpi_table_parse_entries(char *id,
 	       table_end) {
 		if (entry->type == entry_id
 		    && (!max_entries || count++ < max_entries))
-			if (handler(entry, table_end))
+			if (handler(entry, table_end)) {
+				early_acpi_os_unmap_memory((char *)table_header, tbl_size);
 				return -EINVAL;
+			}
 
 		entry = (struct acpi_subtable_header *)
 		    ((unsigned long)entry + entry->length);
@@ -217,6 +220,7 @@ acpi_table_parse_entries(char *id,
 		       "%i found\n", id, entry_id, count - max_entries, count);
 	}
 
+	early_acpi_os_unmap_memory((char *)table_header, tbl_size);
 	return count;
 }
 
@@ -241,17 +245,19 @@ acpi_table_parse_madt(enum acpi_madt_type id,
 int __init acpi_table_parse(char *id, acpi_table_handler handler)
 {
 	struct acpi_table_header *table = NULL;
+	acpi_size tbl_size;
 
 	if (!handler)
 		return -EINVAL;
 
 	if (strncmp(id, ACPI_SIG_MADT, 4) == 0)
-		acpi_get_table(id, acpi_apic_instance, &table);
+		acpi_get_table_with_size(id, acpi_apic_instance, &table, &tbl_size);
 	else
-		acpi_get_table(id, 0, &table);
+		acpi_get_table_with_size(id, 0, &table, &tbl_size);
 
 	if (table) {
 		handler(table);
+		early_acpi_os_unmap_memory(table, tbl_size);
 		return 0;
 	} else
 		return 1;
@@ -265,8 +271,9 @@ int __init acpi_table_parse(char *id, acpi_table_handler handler)
 static void __init check_multiple_madt(void)
 {
 	struct acpi_table_header *table = NULL;
+	acpi_size tbl_size;
 
-	acpi_get_table(ACPI_SIG_MADT, 2, &table);
+	acpi_get_table_with_size(ACPI_SIG_MADT, 2, &table, &tbl_size);
 	if (table) {
 		printk(KERN_WARNING PREFIX
 		       "BIOS bug: multiple APIC/MADT found,"
@@ -275,6 +282,7 @@ static void __init check_multiple_madt(void)
 		       "If \"acpi_apic_instance=%d\" works better, "
 		       "notify linux-acpi@vger.kernel.org\n",
 		       acpi_apic_instance ? 0 : 2);
+		early_acpi_os_unmap_memory(table, tbl_size);
 
 	} else
 		acpi_apic_instance = 0;

include/acpi/acpiosxf.h

@@ -144,6 +144,7 @@ void __iomem *acpi_os_map_memory(acpi_physical_address where,
 				acpi_size length);
 
 void acpi_os_unmap_memory(void __iomem * logical_address, acpi_size size);
+void early_acpi_os_unmap_memory(void __iomem * virt, acpi_size size);
 
 #ifdef ACPI_FUTURE_USAGE
 acpi_status

include/acpi/acpixf.h

@@ -130,6 +130,10 @@ acpi_get_table_header(acpi_string signature,
 		      struct acpi_table_header *out_table_header);
 
 acpi_status
+acpi_get_table_with_size(acpi_string signature,
+	       u32 instance, struct acpi_table_header **out_table,
+	       acpi_size *tbl_size);
+acpi_status
 acpi_get_table(acpi_string signature,
 	       u32 instance, struct acpi_table_header **out_table);
 

include/linux/acpi.h

@@ -79,6 +79,7 @@ typedef int (*acpi_table_handler) (struct acpi_table_header *table);
 typedef int (*acpi_table_entry_handler) (struct acpi_subtable_header *header, const unsigned long end);
 
 char * __acpi_map_table (unsigned long phys_addr, unsigned long size);
+void __init __acpi_unmap_table(char *map, unsigned long size);
 int early_acpi_boot_init(void);
 int acpi_boot_init (void);
 int acpi_boot_table_init (void);