ACPI: Use _TSS for throttling control, when present. Add error checks.

_TSS was erroneously ignored, in favor of the FADT.

When TSS is used, the access width is included in the PTC control/status
register.  So it is unnecessary that the access bit width is multiplied by 8.
At the same time the bit_offset should be considered for system I/O Access.

It should be checked the bit_width and bit_offset of PTC regsiter in order to
avoid the failure of system I/O access. It means that bit_width plus
bit_offset can't be greater than 32.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Li Shaohua <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 35 insertions, 7 deletions

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 5c96ef18e94c..f4b5f7d5dbe6 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -131,6 +131,7 @@ static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
         union acpi_object *ptc = NULL;
         union acpi_object obj = { 0 };
+        struct acpi_processor_throttling *throttling;
 
         status = acpi_evaluate_object(pr->handle, "_PTC", NULL, &buffer);
         if (ACPI_FAILURE(status)) {
@@ -182,6 +183,22 @@ static int acpi_processor_get_throttling_control(struct acpi_processor *pr)
         memcpy(&pr->throttling.status_register, obj.buffer.pointer,
                sizeof(struct acpi_ptc_register));
 
+        throttling = &pr->throttling;
+
+        if ((throttling->control_register.bit_width +
+                throttling->control_register.bit_offset) > 32) {
+                printk(KERN_ERR PREFIX "Invalid _PTC control register\n");
+                result = -EFAULT;
+                goto end;
+        }
+
+        if ((throttling->status_register.bit_width +
+                throttling->status_register.bit_offset) > 32) {
+                printk(KERN_ERR PREFIX "Invalid _PTC status register\n");
+                result = -EFAULT;
+                goto end;
+        }
+
       end:
         kfree(buffer.pointer);
 
@@ -379,7 +396,9 @@ static int acpi_processor_get_throttling_fadt(struct acpi_processor *pr)
 static int acpi_read_throttling_status(struct acpi_processor *pr,
                                         acpi_integer *value)
 {
+        u32 bit_width, bit_offset;
         u64 ptc_value;
+        u64 ptc_mask;
         struct acpi_processor_throttling *throttling;
         int ret = -1;
 
@@ -387,11 +406,14 @@ static int acpi_read_throttling_status(struct acpi_processor *pr,
         switch (throttling->status_register.space_id) {
         case ACPI_ADR_SPACE_SYSTEM_IO:
                 ptc_value = 0;
+                bit_width = throttling->status_register.bit_width;
+                bit_offset = throttling->status_register.bit_offset;
+
                 acpi_os_read_port((acpi_io_address) throttling->status_register.
                                   address, (u32 *) &ptc_value,
-                                  (u32) throttling->status_register.bit_width *
-                                  8);
-                *value = (acpi_integer) ptc_value;
+                                  (u32) (bit_width + bit_offset));
+                ptc_mask = (1 << bit_width) - 1;
+                *value = (acpi_integer) ((ptc_value >> bit_offset) & ptc_mask);
                 ret = 0;
                 break;
         case ACPI_ADR_SPACE_FIXED_HARDWARE:
@@ -408,18 +430,24 @@ static int acpi_read_throttling_status(struct acpi_processor *pr,
 static int acpi_write_throttling_state(struct acpi_processor *pr,
                                 acpi_integer value)
 {
+        u32 bit_width, bit_offset;
         u64 ptc_value;
+        u64 ptc_mask;
         struct acpi_processor_throttling *throttling;
         int ret = -1;
 
         throttling = &pr->throttling;
         switch (throttling->control_register.space_id) {
         case ACPI_ADR_SPACE_SYSTEM_IO:
-                ptc_value = value;
+                bit_width = throttling->control_register.bit_width;
+                bit_offset = throttling->control_register.bit_offset;
+                ptc_mask = (1 << bit_width) - 1;
+                ptc_value = value & ptc_mask;
+
                 acpi_os_write_port((acpi_io_address) throttling->
-                                   control_register.address, (u32) ptc_value,
-                                   (u32) throttling->control_register.
-                                   bit_width * 8);
+                                        control_register.address,
+                                        (u32) (ptc_value << bit_offset),
+                                        (u32) (bit_width + bit_offset));
                 ret = 0;
                 break;
         case ACPI_ADR_SPACE_FIXED_HARDWARE: