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>

diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 5c96ef1..f4b5f7d 100644 (file)
--- 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: