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Commit 7e90560c authored by Luca Tettamanti's avatar Luca Tettamanti Committed by Len Brown
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ACPI: acpi_enforce_resource=strict by default 

Enforce strict resource checking - disallowing access by native
drivers to IO ports and memory regions claimed by ACPI firmware.

The patch is mainly aimed to block native hwmon drivers from touching
monitoring chips that ACPI thinks it own.

If this causes a regression, boot with "acpi_enforce_resources=lax"
which was the previous default.

http://bugzilla.kernel.org/show_bug.cgi?id=12376
http://bugzilla.kernel.org/show_bug.cgi?id=12541



Signed-off-by: default avatarLuca Tettamanti <kronos.it@gmail.com>
Acked-by: default avatarPavel Machek <pavel@suse.cz>
Acked-by: default avatarJean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 8e0ee43b

Documentation/kernel-parameters.txt

+16 −0
Original line number Diff line number Diff line
@@ -258,6 +258,22 @@ and is between 256 and 4096 characters. It is defined in the file 
			to assume that this machine's pmtimer latches its value

			and always returns good values.



	acpi_enforce_resources=	[ACPI]

			{ strict | lax | no }

			Check for resource conflicts between native drivers

			and ACPI OperationRegions (SystemIO and SystemMemory

			only). IO ports and memory declared in ACPI might be

			used by the ACPI subsystem in arbitrary AML code and

			can interfere with legacy drivers.

			strict (default): access to resources claimed by ACPI

			is denied; legacy drivers trying to access reserved

			resources will fail to bind to device using them.

			lax: access to resources claimed by ACPI is allowed;

			legacy drivers trying to access reserved resources

			will bind successfully but a warning message is logged.

			no: ACPI OperationRegions are not marked as reserved,

			no further checks are performed.



	agp=		[AGP]

			{ off | try_unsupported }

			off: disable AGP support

drivers/acpi/osl.c

+3 −3
Original line number Diff line number Diff line
@@ -1063,9 +1063,9 @@ __setup("acpi_wake_gpes_always_on", acpi_wake_gpes_always_on_setup); 
 * in arbitrary AML code and can interfere with legacy drivers.

 * acpi_enforce_resources= can be set to:

 *

 *   - strict           (2)

 *   - strict (default) (2)

 *     -> further driver trying to access the resources will not load

 *   - lax (default)    (1)

 *   - lax              (1)

 *     -> further driver trying to access the resources will load, but you

 *     get a system message that something might go wrong...

 *
@@ -1077,7 +1077,7 @@ __setup("acpi_wake_gpes_always_on", acpi_wake_gpes_always_on_setup); 
#define ENFORCE_RESOURCES_LAX    1

#define ENFORCE_RESOURCES_NO     0



static unsigned int acpi_enforce_resources = ENFORCE_RESOURCES_LAX;

static unsigned int acpi_enforce_resources = ENFORCE_RESOURCES_STRICT;



static int __init acpi_enforce_resources_setup(char *str)

{