Re: [PATCH v1 1/1] DynamicTablesPkg: Add frame number validation to GTDT generator

["Sami Mujawar" <sami.mujawar@arm.com>]

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

-----Original Message-----
From: Krzysztof Koch <krzysztof.koch@arm.com> 
Sent: 08 May 2019 03:05 PM
To: devel@edk2.groups.io
Cc: ard.biesheuvel@linaro.org; Sami Mujawar <Sami.Mujawar@arm.com>; Alexei Fedorov <Alexei.Fedorov@arm.com>; Girish Pathak <Girish.Pathak@arm.com>; Pierre Gondois <Pierre.Gondois@arm.com>; Matteo Carlini <Matteo.Carlini@arm.com>; Stephanie Hughes-Fitt <Stephanie.Hughes-Fitt@arm.com>; nd <nd@arm.com>
Subject: [PATCH v1 1/1] DynamicTablesPkg: Add frame number validation to GTDT generator

Added code to check if the Generic Timer Block Structure's frame number provided by the platform repository is within the allowed range (0-7).

References:
- ACPI 6.2 Errata A, Table 5-122, September 2017

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
---

The changes can be seen at: https://github.com/KrzysztofKoch1/edk2/tree/woa_522_gt_frame_number_validate_v1

Notes:
    v1:
    - Add GTDT Frame Number validation [Krzysztof]

 DynamicTablesPkg/Library/Acpi/Arm/AcpiGtdtLibArm/GtdtGenerator.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/DynamicTablesPkg/Library/Acpi/Arm/AcpiGtdtLibArm/GtdtGenerator.c b/DynamicTablesPkg/Library/Acpi/Arm/AcpiGtdtLibArm/GtdtGenerator.c
index 8d9ddcf9244b9f8b795edf7a53dd8a071bb121bc..543e6f442f2ab93bc7c9cd5e563d305c0f400060 100644
--- a/DynamicTablesPkg/Library/Acpi/Arm/AcpiGtdtLibArm/GtdtGenerator.c
+++ b/DynamicTablesPkg/Library/Acpi/Arm/AcpiGtdtLibArm/GtdtGenerator.c
@@ -218,6 +218,15 @@ AddGTBlockTimerFrames (
       GtBlockFrame
       ));
 
+    if (GTBlockTimerFrameList->FrameNumber >= 8) {
+      DEBUG ((
+        DEBUG_ERROR,
+        "ERROR: GTDT: Frame number %d is not in the range 0-7\n",
+        GTBlockTimerFrameList->FrameNumber
+      ));
+      return EFI_INVALID_PARAMETER;
+    }
+
     GtBlockFrame->GTFrameNumber = GTBlockTimerFrameList->FrameNumber;
     GtBlockFrame->Reserved[0] = EFI_ACPI_RESERVED_BYTE;
     GtBlockFrame->Reserved[1] = EFI_ACPI_RESERVED_BYTE;
--
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'