From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
According to the STAO table, hide UART used by Xen from Dom0.
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
---
drivers/acpi/bus.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index a212cef..e93806b 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -46,6 +46,7 @@ ACPI_MODULE_NAME("bus");
struct acpi_device *acpi_root;
struct proc_dir_entry *acpi_root_dir;
EXPORT_SYMBOL(acpi_root_dir);
+static u64 uart_addr;
#ifdef CONFIG_X86
#ifdef CONFIG_ACPI_CUSTOM_DSDT
@@ -93,6 +94,16 @@ acpi_status acpi_bus_get_status_handle(acpi_handle handle,
{
acpi_status status;
+ if (uart_addr) {
+ u64 addr;
+ status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL,
+ &addr);
+ if (ACPI_SUCCESS(status) && (addr == uart_addr)) {
+ *sta = 0;
+ return AE_OK;
+ }
+ }
+
status = acpi_evaluate_integer(handle, "_STA", NULL, sta);
if (ACPI_SUCCESS(status))
return AE_OK;
@@ -1069,6 +1080,7 @@ EXPORT_SYMBOL_GPL(acpi_kobj);
static int __init acpi_init(void)
{
int result;
+ struct acpi_table_stao *stao_ptr;
if (acpi_disabled) {
printk(KERN_INFO PREFIX "Interpreter disabled.\n");
@@ -1081,6 +1093,16 @@ static int __init acpi_init(void)
acpi_kobj = NULL;
}
+ acpi_get_table(ACPI_SIG_STAO, 1,
+ (struct acpi_table_header **)&stao_ptr);
+ if(stao_ptr->ignore_uart)
+ {
+ struct acpi_table_spcr *spcr_ptr;
+ acpi_get_table(ACPI_SIG_SPCR, 1,
+ (struct acpi_table_header **)&spcr_ptr);
+ uart_addr = spcr_ptr->serial_port.address;
+ }
+
init_acpi_device_notify();
result = acpi_bus_init();
if (result) {
--
2.1.0
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