Hi Pedro,
Firstly, thanks for your comments, let me explain.
- "C99 flexible array members have been well defined and well
supported
for maybe 20 years in GCC (https://godbolt.org/z/9qxKar4f6)" =>
Yes, I agree and there's no
comment from my side but this is completely
different with current issue, why? Please see the bellow
explanation.
- When we define the PCD to map with any structure in .dec file,
BaseTools will gen PcdValueInit.c.
In this file, there're a lot of using "__FIELD_SIZE(REST_EX_SERVICE_DEVICE_PATH_DATA,
DevicePath);"
and this is the definiton of this macro "#define
__FIELD_SIZE(TYPE, Field) (sizeof((TYPE *)0)->Field)".
When using "__STATIC_ASSERT((__FIELD_SIZE(REST_EX_SERVICE_DEVICE_PATH_DATA,
DevicePath) >= 3) ||
(__FIELD_SIZE(REST_EX_SERVICE_DEVICE_PATH_DATA,
DevicePath) == 0), "Input buffer exceeds the buffer array");",
"(sizeof((TYPE *)0)->Field" will be an error (error:
invalid application of ‘sizeof’ to incomplete type
EFI_DEVICE_PATH_PROTOCOL[]) => will
cause error on "__STATIC_ASSERT" because _Static_assert requires
its first parameter
to be a constant expression => the error message when compile
this code is "Line 257 Value {0x03,0x0b,0x25,0x00,0x00,0x1b,
0x21,0xdc,0x35,0xb0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x01,0x7f,0xff,0x04,0x00}:293:19:
error: expression in static assertion is not an integer"
- An other demonstation on other platforms in this behavior: you
can check at edk2-platforms/Features/Intel/SystemInformation/SmbiosFeaturePkg/SmbiosFeaturePkg.dec.
gSmbiosFeaturePkgTokenSpaceGuid.PcdSmbiosType0BiosInformation|{0x0}|SMBIOS_TABLE_TYPE0|0xD0000001
{
<HeaderFiles>
IndustryStandard/SmBios.h
<Packages>
MdePkg/MdePkg.dec
SystemInformation/SmbiosFeaturePkg/SmbiosFeaturePkg.dec
}
gSmbiosFeaturePkgTokenSpaceGuid.PcdSmbiosType0BiosInformation.BIOSCharacteristicsExtensionBytes[0]|0x33
gSmbiosFeaturePkgTokenSpaceGuid.PcdSmbiosType0BiosInformation.BIOSCharacteristicsExtensionBytes[1]|0x0F
This is the declaration to map PcdSmbiosType0BiosInformation with
SMBIOS_TABLE_TYPE0 structure and
the declaration of BIOSCharacteristicsExtensionBytes is "UINT8
BIOSCharacteristicsExtensionBytes[2];". If
we remove the number of elements (2) to flexible array, we will
see the same error like "Index of
BIOSCharacteristicsExtensionBytes[0]:361:19:
error: expression in static assertion is not an
integer".
=> Conclusion: This is not problem on compiler, it just comes
from the way BasTools gen PcdValueInit.c
and define macros for this case (map PCD structure to any
structure). I hope it satisfy your concerns.
Thanks,
Minh Nguyen.
On Fri, May 5, 2023 at 6:12 PM Minh Nguyen via groups.io <minhnguyen1=os.amperecomputing.com@groups.io> wrote:From: Vu Nguyen <vunguyen@os.amperecomputing.com> It requires a fixed size array to store the content of device path PCD. Add the array size to solve this issue. Signed-off-by: Minh Nguyen <minhnguyen1@os.amperecomputing.com> Cc: Abner Chang <abner.chang@amd.com> Cc: Igor Kulchytskyy <igork@ami.com> Cc: Nick Ramirez <nramirez@nvidia.com> Reviewed-by: Abner Chang <Abner.Chang@amd.com> --- RedfishPkg/Include/Pcd/RestExServiceDevicePath.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/RedfishPkg/Include/Pcd/RestExServiceDevicePath.h b/RedfishPkg/Include/Pcd/RestExServiceDevicePath.h index 91b1198297c2..57fc199f61f2 100644 --- a/RedfishPkg/Include/Pcd/RestExServiceDevicePath.h +++ b/RedfishPkg/Include/Pcd/RestExServiceDevicePath.h @@ -4,6 +4,7 @@ Copyright (c) 2019, Intel Corporation. All rights reserved.<BR> (C) Copyright 2020 Hewlett Packard Enterprise Development LP<BR> + Copyright (c) 2023, Ampere Computing LLC. All rights reserved.<BR> SPDX-License-Identifier: BSD-2-Clause-Patent @@ -14,6 +15,8 @@ #include <Protocol/DevicePath.h> +#define MAX_DEVICE_PATH_NODE 40 + typedef enum { DEVICE_PATH_MATCH_MAC_NODE = 1, DEVICE_PATH_MATCH_PCI_NODE = 2, @@ -32,7 +35,7 @@ typedef struct { // 0x03,0x0b,0x25,0x00,0x00,0x50,0x56,0xc0,0x00,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01, // 0x7f,0xff,0x04,0x00} // - EFI_DEVICE_PATH_PROTOCOL DevicePath[]; + EFI_DEVICE_PATH_PROTOCOL DevicePath[MAX_DEVICE_PATH_NODE]; } REST_EX_SERVICE_DEVICE_PATH_DATA;This doesn't work (changes the meaning) and may possibly break ABI. What error do you get? What compiler? C99 flexible array members have been well defined and well supported for maybe 20 years in GCC (https://godbolt.org/z/9qxKar4f6)