Commit aa714d28 authored Mar 04, 2015 by Jiang Liu Committed by Rafael J. Wysocki Mar 04, 2015

x86/PCI/ACPI: Relax ACPI resource descriptor checks to work around BIOS bugs

Some BIOSes report incorrect length for ACPI address space descriptors,
so relax the checks to avoid regressions. This issue has appeared several
times as:
 3162b6f0 ("PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
 d558b483 ("x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
 f238b414 ("PNPACPI: compute Address Space length rather than using _LEN")
 48728e07 ("x86/PCI: compute Address Space length rather than using _LEN")

Please refer to https://bugzilla.kernel.org/show_bug.cgi?id=94221
for more details and example malformed ACPI resource descriptors.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=94221


Fixes: 593669c2 (x86/PCI/ACPI: Use common ACPI resource interfaces ...)
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Tested-by: Dave Airlie <airlied@redhat.com>
Tested-by: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent 63f1789e

drivers/acpi/resource.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -42,8 +42,10 @@ static bool acpi_dev_resource_len_valid(u64 start, u64 end, u64 len, bool io)
	* CHECKME: len might be required to check versus a minimum		* CHECKME: len might be required to check versus a minimum
	* length as well. 1 for io is fine, but for memory it does		* length as well. 1 for io is fine, but for memory it does
	* not make any sense at all.		* not make any sense at all.
			* Note: some BIOSes report incorrect length for ACPI address space
			* descriptor, so remove check of 'reslen == len' to avoid regression.
	*/		*/
	if (len && reslen && reslen == len && start <= end)		if (len && reslen && start <= end)
	return true;		return true;

	pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",		pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",

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