RE: [buggy index field handling] [patch]

[Nate Lawson <nate-Y6VGUYTwhu0@public.gmane.org>]

No, that is not the right patch.  The better one is at the bottom of my
email, by Robert Vollmert.

-Nate

On Tue, 23 Sep 2003, Moore, Robert wrote:
> Is this the final patch?  If so, we will integrate it into the ACPI CA
> core
> Bob
>
> -----Original Message-----
> From: acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
> [mailto:acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org] On Behalf Of Ducrot
> Bruno
> Sent: Monday, September 22, 2003 10:19 AM
> To: Grover, Andrew
> Cc: acpi-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org; Robert Vollmert; Mads Paulin
> Subject: [ACPI] [buggy index field handling] [patch]
>
> Hi Andy,
>
> There is a funny bug in acpi/executer/exfldio.c::acpi_ex_field_datum_io
> When the field come from an indexed one, we read all the time from the
> address obj_desc->index_field.value
> Unfortunately, this is wrong, since the correct address is
> obviously &obj_desc->index_field.value + field_datum_byte_offset
>
> --- linux-2.6.0-test5/drivers/acpi/executer/exfldio.c	2003/09/22
> 17:09:20	1.1
> +++ linux-2.6.0-test5/drivers/acpi/executer/exfldio.c	2003/09/22
> 17:10:11
> @@ -425,7 +425,7 @@
>  		/* Write the index value to the index_register (itself a
> region_field) */
>
>  		status = acpi_ex_insert_into_field
> (obj_desc->index_field.index_obj,
> -				 &obj_desc->index_field.value,
> +				 &obj_desc->index_field.value +
> field_datum_byte_offset,
>  				 sizeof (obj_desc->index_field.value));
>  		if (ACPI_FAILURE (status)) {
>  			return_ACPI_STATUS (status);

Here's a patch.

--- exfldio.c.orig	2003-09-22 18:22:09.000000000 +0200
+++ exfldio.c	2003-09-22 19:16:11.000000000 +0200
@@ -346,6 +346,7 @@
 {
 	acpi_status                     status;
 	acpi_integer                    local_value;
+	acpi_integer                    index_field_value;


 	ACPI_FUNCTION_TRACE_U32 ("ex_field_datum_io", field_datum_byte_offset);
@@ -448,18 +449,22 @@

 	case ACPI_TYPE_LOCAL_INDEX_FIELD:

+		/* Compute index value to access the current datum */
+
+		index_field_value = (acpi_integer) obj_desc->index_field.value
+			+ field_datum_byte_offset;

 		/* Ensure that the index_value is not beyond the capacity of the register */

 		if (acpi_ex_register_overflow (obj_desc->index_field.index_obj,
-				  (acpi_integer) obj_desc->index_field.value)) {
+					       index_field_value)) {
 			return_ACPI_STATUS (AE_AML_REGISTER_LIMIT);
 		}

 		/* Write the index value to the index_register (itself a region_field) */

 		status = acpi_ex_insert_into_field (obj_desc->index_field.index_obj,
-				 &obj_desc->index_field.value,
+				 &index_field_value,
 				 sizeof (obj_desc->index_field.value));
 		if (ACPI_FAILURE (status)) {
 			return_ACPI_STATUS (status);




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