1 files changed, 83 insertions, 39 deletions

diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
index d8b1b39aa9db..1a0bfd43f8f0 100644
--- a/drivers/platform/x86/dell-laptop.c
+++ b/drivers/platform/x86/dell-laptop.c
@@ -22,6 +22,7 @@
 #include <linux/rfkill.h>
 #include <linux/power_supply.h>
 #include <linux/acpi.h>
+#include <linux/mm.h>
 #include <linux/i8042.h>
 #include "../../firmware/dcdbas.h"
 
@@ -123,6 +124,21 @@ static struct dmi_system_id __devinitdata dell_blacklist[] = {
         {}
 };
 
+static struct calling_interface_buffer *buffer;
+struct page *bufferpage;
+DEFINE_MUTEX(buffer_mutex);
+
+static void get_buffer(void)
+{
+        mutex_lock(&buffer_mutex);
+        memset(buffer, 0, sizeof(struct calling_interface_buffer));
+}
+
+static void release_buffer(void)
+{
+        mutex_unlock(&buffer_mutex);
+}
+
 static void __init parse_da_table(const struct dmi_header *dm)
 {
         /* Final token is a terminator, so we don't want to copy it */
@@ -225,30 +241,35 @@ dell_send_request(struct calling_interface_buffer *buffer, int class,
 
 static int dell_rfkill_set(void *data, bool blocked)
 {
-        struct calling_interface_buffer buffer;
         int disable = blocked ? 1 : 0;
         unsigned long radio = (unsigned long)data;
+        int ret = 0;
 
-        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
-        dell_send_request(&buffer, 17, 11);
-        if (!(buffer.output[1] & BIT(16)))
-                return -EINVAL;
+        get_buffer();
+        dell_send_request(buffer, 17, 11);
 
-        buffer.input[0] = (1 | (radio<<8) | (disable << 16));
-        dell_send_request(&buffer, 17, 11);
+        if (!(buffer->output[1] & BIT(16))) {
+                ret = -EINVAL;
+                goto out;
+        }
 
-        return 0;
+        buffer->input[0] = (1 | (radio<<8) | (disable << 16));
+        dell_send_request(buffer, 17, 11);
+
+out:
+        release_buffer();
+        return ret;
 }
 
 static void dell_rfkill_query(struct rfkill *rfkill, void *data)
 {
-        struct calling_interface_buffer buffer;
         int status;
         int bit = (unsigned long)data + 16;
 
-        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
-        dell_send_request(&buffer, 17, 11);
-        status = buffer.output[1];
+        get_buffer();
+        dell_send_request(buffer, 17, 11);
+        status = buffer->output[1];
+        release_buffer();
 
         rfkill_set_sw_state(rfkill, !!(status & BIT(bit)));
         rfkill_set_hw_state(rfkill, !(status & BIT(16)));
@@ -273,7 +294,6 @@ static DECLARE_DELAYED_WORK(dell_rfkill_work, dell_update_rfkill);
 
 static int __init dell_setup_rfkill(void)
 {
-        struct calling_interface_buffer buffer;
         int status;
         int ret;
 
@@ -283,9 +303,10 @@ static int __init dell_setup_rfkill(void)
                 return 0;
         }
 
-        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
-        dell_send_request(&buffer, 17, 11);
-        status = buffer.output[1];
+        get_buffer();
+        dell_send_request(buffer, 17, 11);
+        status = buffer->output[1];
+        release_buffer();
 
         if ((status & (1<<2|1<<8)) == (1<<2|1<<8)) {
                 wifi_rfkill = rfkill_alloc("dell-wifi", &platform_device->dev,
@@ -361,39 +382,49 @@ static void dell_cleanup_rfkill(void)
 
 static int dell_send_intensity(struct backlight_device *bd)
 {
-        struct calling_interface_buffer buffer;
+        int ret = 0;
 
-        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
-        buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
-        buffer.input[1] = bd->props.brightness;
+        get_buffer();
+        buffer->input[0] = find_token_location(BRIGHTNESS_TOKEN);
+        buffer->input[1] = bd->props.brightness;
 
-        if (buffer.input[0] == -1)
-                return -ENODEV;
+        if (buffer->input[0] == -1) {
+                ret = -ENODEV;
+                goto out;
+        }
 
         if (power_supply_is_system_supplied() > 0)
-                dell_send_request(&buffer, 1, 2);
+                dell_send_request(buffer, 1, 2);
         else
-                dell_send_request(&buffer, 1, 1);
+                dell_send_request(buffer, 1, 1);
 
+out:
+        release_buffer();
         return 0;
 }
 
 static int dell_get_intensity(struct backlight_device *bd)
 {
-        struct calling_interface_buffer buffer;
+        int ret = 0;
 
-        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
-        buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
+        get_buffer();
+        buffer->input[0] = find_token_location(BRIGHTNESS_TOKEN);
 
-        if (buffer.input[0] == -1)
-                return -ENODEV;
+        if (buffer->input[0] == -1) {
+                ret = -ENODEV;
+                goto out;
+        }
 
         if (power_supply_is_system_supplied() > 0)
-                dell_send_request(&buffer, 0, 2);
+                dell_send_request(buffer, 0, 2);
         else
-                dell_send_request(&buffer, 0, 1);
+                dell_send_request(buffer, 0, 1);
 
-        return buffer.output[1];
+out:
+        release_buffer();
+        if (ret)
+                return ret;
+        return buffer->output[1];
 }
 
 static struct backlight_ops dell_ops = {
@@ -427,7 +458,6 @@ bool dell_laptop_i8042_filter(unsigned char data, unsigned char str,
 
 static int __init dell_init(void)
 {
-        struct calling_interface_buffer buffer;
         int max_intensity = 0;
         int ret;
 
@@ -453,6 +483,17 @@ static int __init dell_init(void)
         if (ret)
                 goto fail_platform_device2;
 
+        /*
+         * Allocate buffer below 4GB for SMI data--only 32-bit physical addr
+         * is passed to SMI handler.
+         */
+        bufferpage = alloc_page(GFP_KERNEL | GFP_DMA32);
+
+        if (!bufferpage)
+                goto fail_buffer;
+        buffer = page_address(bufferpage);
+        mutex_init(&buffer_mutex);
+
         ret = dell_setup_rfkill();
 
         if (ret) {
@@ -475,13 +516,13 @@ static int __init dell_init(void)
                 return 0;
 #endif
 
-        memset(&buffer, 0, sizeof(struct calling_interface_buffer));
-        buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
-
-        if (buffer.input[0] != -1) {
-                dell_send_request(&buffer, 0, 2);
-                max_intensity = buffer.output[3];
+        get_buffer();
+        buffer->input[0] = find_token_location(BRIGHTNESS_TOKEN);
+        if (buffer->input[0] != -1) {
+                dell_send_request(buffer, 0, 2);
+                max_intensity = buffer->output[3];
         }
+        release_buffer();
 
         if (max_intensity) {
                 dell_backlight_device = backlight_device_register(
@@ -508,6 +549,8 @@ fail_backlight:
 fail_filter:
         dell_cleanup_rfkill();
 fail_rfkill:
+        free_page((unsigned long)bufferpage);
+fail_buffer:
         platform_device_del(platform_device);
 fail_platform_device2:
         platform_device_put(platform_device);
@@ -529,6 +572,7 @@ static void __exit dell_exit(void)
                 platform_driver_unregister(&platform_driver);
         }
         kfree(da_tokens);
+        free_page((unsigned long)buffer);
 }
 
 module_init(dell_init);