[PATCH 1/2] Remove length test for ACPI 1.0 RSDPs, fix checks against revision field

[Alex Hung]

From: Chris Goldsworthy <goldswo at amazon.com>

Remove RSDP length test for ACPI 1.0 RSDPs.  Fix RSDP revision field checks to
check against revision values 0 and 2 only.

The RSDP length field test for ACPI 1.0 RSDPs is invalid, since a ACPI 1.0 RSDP
has no length field.  FWTS also checks the RSDP revision number incorrectly -
the revision field of a ACPI 1.0 RSDP has a value of 0, not 1 (as per ACPI
specification version 6.2, page 122).

Add descriptions for specific RSDP tests.

Fix a typo in a RSDT error message.

Signed-off-by: Christopher Goldsworthy <goldswo at amazon.de>
---
 src/acpi/rsdp/rsdp.c | 27 ++++++++++++---------------
 src/acpi/rsdt/rsdt.c |  2 +-
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/src/acpi/rsdp/rsdp.c b/src/acpi/rsdp/rsdp.c
index becdbb2..2f537be 100644
--- a/src/acpi/rsdp/rsdp.c
+++ b/src/acpi/rsdp/rsdp.c
@@ -80,6 +80,7 @@ static int rsdp_test1(fwts_framework *fw)
 			    "RSDPBadFirstChecksum",
 			    "RSDP first checksum is incorrect: 0x%x", checksum);
 
+	/* ensure oem_id only contains printable characters */
 	for (i = 0; i < 6; i++) {
 		if (!isprint(rsdp->oem_id[i])) {
 			passed = false;
@@ -102,27 +103,23 @@ static int rsdp_test1(fwts_framework *fw)
 			"firmware ACPI complaint.");
 	}
 
-	/* ACPI 6.1 errata clarifies revision 1 must have length 20 */
-	if (rsdp->revision == 1) {
-		if (rsdp->length == 20)
-			fwts_passed(fw, "RSDP: the table is the correct length.");
-		else
-			fwts_failed(fw, LOG_LEVEL_MEDIUM,
-				"RSDPBadLength",
-				"RSDP: length of Revision 1 is %d bytes but should be 20.",
-				rsdp->length);
-
-		return FWTS_OK;
-	}
-
-	if (rsdp->revision <= 2)
+	/* check if revision number is valid. note: revision field for
+	 * ACPI 1.0 RSDP is 0, not 1, as per ACPI specification version
+	 * 6.2, p.122. */
+	if (rsdp->revision == 0 || rsdp->revision == 2)
 		fwts_passed(fw,
 			    "RSDP: revision is %" PRIu8 ".", rsdp->revision);
 	else
 		fwts_failed(fw, LOG_LEVEL_MEDIUM,
 			"RSDPBadRevisionId",
 			"RSDP: revision is %" PRIu8 ", expected "
-			"value less than 2.", rsdp->revision);
+			"value to be 0 or 2.", rsdp->revision);
+
+	/* all proceeding tests involve fields which are only
+	 * defined in ACPI specifications 2.0 and greater, skip
+	 * if ACPI version is 1.0 */
+	if (rsdp->revision == 0)
+		return FWTS_OK;
 
 	/* whether RSDT or XSDT depends arch */
 	if (rsdp->rsdt_address == 0 && rsdp->xsdt_address == 0)
diff --git a/src/acpi/rsdt/rsdt.c b/src/acpi/rsdt/rsdt.c
index bb28e20..3374b8b 100644
--- a/src/acpi/rsdt/rsdt.c
+++ b/src/acpi/rsdt/rsdt.c
@@ -60,7 +60,7 @@ static int rsdt_test1(fwts_framework *fw)
 				"RSDTEntryNull",
 				"RSDT Entry %zd is null, should not be non-zero.", i);
 			fwts_advice(fw,
-				"A XSDT pointer is null and therefore erroneously "
+				"A RSDT pointer is null and therefore erroneously "
 				"points to an invalid 32 bit ACPI table header. "
 				"At worse this will cause the kernel to oops, at "
 				"best the kernel may ignore this.  However, it "
-- 
2.10.1 (Apple Git-78)