From: Len Brown <len.brown@xxxxxxxxx>
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@xxxxxxxxx>
---
drivers/acpi/osl.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 6729a49..4fb01b0 100644
--- 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 */
--
1.6.1.2.319.gbd9e
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