ACPI: make some IO ports off-limits to AML

ACPICA exports acpi_os_validate_address() so the OS
can prevent BIOS AML from accessing specified addresses.

Start using this interface to prevent AML from accessing
some well known IO addresses that the OS "owns".

Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 6729a4992f2bd73543a561f36454f037db01298d..4fb01b0133c77629bbdf5eef0b2f9ef659600b34 100644 (file)
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -1317,6 +1317,54 @@ acpi_os_validate_interface (char *interface)
        return AE_SUPPORT;
 }
 
+#ifdef CONFIG_X86
+
+struct aml_port_desc {
+       uint    start;
+       uint    end;
+       char*   name;
+       char    warned;
+};
+
+static struct aml_port_desc aml_invalid_port_list[] = {
+       {0x20, 0x21, "PIC0", 0},
+       {0xA0, 0xA1, "PIC1", 0},
+       {0x4D0, 0x4D1, "ELCR", 0}
+};
+
+/*
+ * valid_aml_io_address()
+ *
+ * if valid, return true
+ * else invalid, warn once, return false
+ */
+static bool valid_aml_io_address(uint address, uint length)
+{
+       int i;
+       int entries = sizeof(aml_invalid_port_list) / sizeof(struct aml_port_desc);
+
+       for (i = 0; i < entries; ++i) {
+               if ((address >= aml_invalid_port_list[i].start &&
+                       address <= aml_invalid_port_list[i].end) ||
+                       (address + length >= aml_invalid_port_list[i].start &&
+                       address  + length <= aml_invalid_port_list[i].end))
+               {
+                       if (!aml_invalid_port_list[i].warned)
+                       {
+                               printk(KERN_ERR "ACPI: Denied BIOS AML access"
+                                       " to invalid port 0x%x+0x%x (%s)\n",
+                                       address, length,
+                                       aml_invalid_port_list[i].name);
+                               aml_invalid_port_list[i].warned = 1;
+                       }
+                       return false;   /* invalid */
+               }
+       }
+       return true;    /* valid */
+}
+#else
+static inline bool valid_aml_io_address(uint address, uint length) { return true; }
+#endif
 /******************************************************************************
  *
  * FUNCTION:    acpi_os_validate_address
@@ -1346,6 +1394,8 @@ acpi_os_validate_address (
 
        switch (space_id) {
        case ACPI_ADR_SPACE_SYSTEM_IO:
+               if (!valid_aml_io_address(address, length))
+                       return AE_AML_ILLEGAL_ADDRESS;
        case ACPI_ADR_SPACE_SYSTEM_MEMORY:
                /* Only interference checks against SystemIO and SytemMemory
                   are needed */