diff mbox

[Bugfix,2/2] x86/PCI/ACPI: Relax ACPI resource descriptor checks to work around BIOS bugs

Message ID 1425458832-28777-2-git-send-email-jiang.liu@linux.intel.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Jiang Liu March 4, 2015, 8:47 a.m. UTC
Some BIOSes report incorrect length for ACPI address space descriptors,
so relax the checks to avoid regressions. This issue has appeared several
times as:
3162b6f0c5e1 ("PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
d558b483d5a7 ("x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
f238b414a74a ("PNPACPI: compute Address Space length rather than using _LEN")
48728e077480 ("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.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Tested-by: Dave Airlie <airlied@redhat.com>
Tested-by: Prakash Punnoor <prakash@punnoor.de>
---
 drivers/acpi/resource.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Rafael J. Wysocki March 4, 2015, 2:26 p.m. UTC | #1
On Wednesday, March 04, 2015 04:47:12 PM Jiang Liu wrote:
> Some BIOSes report incorrect length for ACPI address space descriptors,
> so relax the checks to avoid regressions. This issue has appeared several
> times as:
> 3162b6f0c5e1 ("PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
> d558b483d5a7 ("x86/PCI: truncate _CRS windows with _LEN > _MAX - _MIN + 1")
> f238b414a74a ("PNPACPI: compute Address Space length rather than using _LEN")
> 48728e077480 ("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.
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> Tested-by: Dave Airlie <airlied@redhat.com>
> Tested-by: Prakash Punnoor <prakash@punnoor.de>

Queued up for 4.0-rc3, thanks!

Bjorn, please let me know if you have any objections.

> ---
>  drivers/acpi/resource.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
> index c723668e3e27..5589a6e2a023 100644
> --- a/drivers/acpi/resource.c
> +++ b/drivers/acpi/resource.c
> @@ -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
>  	 * length as well. 1 for io is fine, but for memory it does
>  	 * 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;
>  
>  	pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",
>
diff mbox

Patch

diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index c723668e3e27..5589a6e2a023 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -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
 	 * length as well. 1 for io is fine, but for memory it does
 	 * 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;
 
 	pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",