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>

1 files changed, 14 insertions, 6 deletions

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index a8852952fac4..fec1ae36d431 100644
--- a/drivers/acpi/tables.c
+++ b/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;