[ 066/122] ACPI, APEI: Fixup common access width firmware bug

[Greg Kroah-Hartman]

From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>

3.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jean Delvare <jdelvare@xxxxxxx>

commit f712c71f7b2b43b894d1e92e1b77385fcad8815f upstream.

Many firmwares have a common register definition bug where 8-bit
access width is specified for a 32-bit register. Ideally this should
be fixed in the BIOS, but earlier versions of the kernel did not
complain, so fix that up silently.

This closes kernel bug #43282:
https://bugzilla.kernel.org/show_bug.cgi?id=43282

Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
Acked-by: Huang Ying <ying.huang@xxxxxxxxx>
Acked-by: Gary Hade <garyhade@xxxxxxxxxx>
Signed-off-by: Len Brown <len.brown@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/acpi/apei/apei-base.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/acpi/apei/apei-base.c
+++ b/drivers/acpi/apei/apei-base.c
@@ -586,6 +586,11 @@ static int apei_check_gar(struct acpi_ge
 	}
 	*access_bit_width = 1UL << (access_size_code + 2);
 
+	/* Fixup common BIOS bug */
+	if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 &&
+	    *access_bit_width < 32)
+		*access_bit_width = 32;
+
 	if ((bit_width + bit_offset) > *access_bit_width) {
 		pr_warning(FW_BUG APEI_PFX
 			   "Invalid bit width + offset in GAR [0x%llx/%u/%u/%u/%u]\n",


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