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Date:   Wed, 9 Nov 2022 20:33:34 +1300
From:   Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
To:     Harry Wentland <harry.wentland@amd.com>,
        Leo Li <sunpeng.li@amd.com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Christian =?utf-8?B?S8O2bmln?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>,
        Rongguang Wei <weirongguang@kylinos.cn>,
        Slark Xiao <slark_xiao@163.com>, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org
Cc:     linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
        paulo.miguel.almeida.rodenas@gmail.com
Subject: [PATCH] [next] drm/amdgpu: Replace one-element array with flex-array
 member
Message-ID: <Y2tXzlBDxgg9WMl7@mail.google.com>
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One-element arrays are deprecated, and we are replacing them with
flexible array members instead. So, replace one-element array with
flexible-array member in structs _ATOM_CONNECTOR_DEVICE_TAG_RECORD,
_ATOM_OBJECT_GPIO_CNTL_RECORD, _ATOM_BRACKET_LAYOUT_RECORD,
_ATOM_BRACKET_LAYOUT_RECORD, _ATOM_LEAKAGE_VOLTAGE_OBJECT_V3,
_ATOM_FUSION_SYSTEM_INFO_V3, _ATOM_I2C_DATA_RECORD,
_ATOM_I2C_DEVICE_SETUP_INFO, _ATOM_ASIC_MVDD_INFO and refactor the
rest of the code accordingly. While at it, removed a redundant casting.

Important to mention is that doing a build before/after this patch results
in no binary output differences.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/238
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
---

Alex, I noticed a few structs in atombios.h that were not referenced. Is
there any appetite for removing them? Or is that one of those cases
where the structs are there should one driver ever need it?

Ex.:
	struct _ATOM_I2C_DATA_RECORD
	struct _ATOM_I2C_DEVICE_SETUP_INFO
	struct _ATOM_ASIC_MVDD_INFO
---
 .../gpu/drm/amd/display/dc/bios/bios_parser.c    |  5 ++---
 drivers/gpu/drm/amd/include/atombios.h           | 16 ++++++++--------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/bios/bios_parser.c b/drivers/gpu/drm/amd/display/dc/bios/bios_parser.c
index 39dd8b2dc254..6b9e64cd4379 100644
--- a/drivers/gpu/drm/amd/display/dc/bios/bios_parser.c
+++ b/drivers/gpu/drm/amd/display/dc/bios/bios_parser.c
@@ -2606,8 +2606,7 @@ static enum bp_result update_slot_layout_info(
 
 	for (;;) {
 
-		record_header = (ATOM_COMMON_RECORD_HEADER *)
-			GET_IMAGE(ATOM_COMMON_RECORD_HEADER, record_offset);
+		record_header = GET_IMAGE(ATOM_COMMON_RECORD_HEADER, record_offset);
 		if (record_header == NULL) {
 			result = BP_RESULT_BADBIOSTABLE;
 			break;
@@ -2621,7 +2620,7 @@ static enum bp_result update_slot_layout_info(
 
 		if (record_header->ucRecordType ==
 			ATOM_BRACKET_LAYOUT_RECORD_TYPE &&
-			sizeof(ATOM_BRACKET_LAYOUT_RECORD)
+			struct_size(record, asConnInfo, 1)
 			<= record_header->ucRecordSize) {
 			record = (ATOM_BRACKET_LAYOUT_RECORD *)
 				(record_header);
diff --git a/drivers/gpu/drm/amd/include/atombios.h b/drivers/gpu/drm/amd/include/atombios.h
index 55ae93c1e365..60c44a8a067f 100644
--- a/drivers/gpu/drm/amd/include/atombios.h
+++ b/drivers/gpu/drm/amd/include/atombios.h
@@ -4733,7 +4733,7 @@ typedef struct  _ATOM_CONNECTOR_DEVICE_TAG_RECORD
   ATOM_COMMON_RECORD_HEADER   sheader;
   UCHAR                       ucNumberOfDevice;
   UCHAR                       ucReserved;
-  ATOM_CONNECTOR_DEVICE_TAG   asDeviceTag[1];         //This Id is same as "ATOM_DEVICE_XXX_SUPPORT", 1 is only for allocation
+  ATOM_CONNECTOR_DEVICE_TAG   asDeviceTag[];	       //This Id is same as "ATOM_DEVICE_XXX_SUPPORT"
 }ATOM_CONNECTOR_DEVICE_TAG_RECORD;
 
 
@@ -4793,7 +4793,7 @@ typedef struct  _ATOM_OBJECT_GPIO_CNTL_RECORD
   ATOM_COMMON_RECORD_HEADER   sheader;
   UCHAR                       ucFlags;                // Future expnadibility
   UCHAR                       ucNumberOfPins;         // Number of GPIO pins used to control the object
-  ATOM_GPIO_PIN_CONTROL_PAIR  asGpio[1];              // the real gpio pin pair determined by number of pins ucNumberOfPins
+  ATOM_GPIO_PIN_CONTROL_PAIR  asGpio[];               // the real gpio pin pair determined by number of pins ucNumberOfPins
 }ATOM_OBJECT_GPIO_CNTL_RECORD;
 
 //Definitions for GPIO pin state
@@ -4982,7 +4982,7 @@ typedef struct  _ATOM_BRACKET_LAYOUT_RECORD
   UCHAR                       ucWidth;
   UCHAR                       ucConnNum;
   UCHAR                       ucReserved;
-  ATOM_CONNECTOR_LAYOUT_INFO  asConnInfo[1];
+  ATOM_CONNECTOR_LAYOUT_INFO  asConnInfo[];
 }ATOM_BRACKET_LAYOUT_RECORD;
 
 
@@ -5161,7 +5161,7 @@ typedef struct  _ATOM_GPIO_VOLTAGE_OBJECT_V3
    UCHAR  ucPhaseDelay;                      // phase delay in unit of micro second
    UCHAR  ucReserved;
    ULONG  ulGpioMaskVal;                     // GPIO Mask value
-   VOLTAGE_LUT_ENTRY_V2 asVolGpioLut[1];
+   VOLTAGE_LUT_ENTRY_V2 asVolGpioLut[];
 }ATOM_GPIO_VOLTAGE_OBJECT_V3;
 
 typedef struct  _ATOM_LEAKAGE_VOLTAGE_OBJECT_V3
@@ -5171,7 +5171,7 @@ typedef struct  _ATOM_LEAKAGE_VOLTAGE_OBJECT_V3
    UCHAR    ucLeakageEntryNum;               // indicate the entry number of LeakageId/Voltage Lut table
    UCHAR    ucReserved[2];
    ULONG    ulMaxVoltageLevel;
-   LEAKAGE_VOLTAGE_LUT_ENTRY_V2 asLeakageIdLut[1];
+   LEAKAGE_VOLTAGE_LUT_ENTRY_V2 asLeakageIdLut[];
 }ATOM_LEAKAGE_VOLTAGE_OBJECT_V3;
 
 
@@ -6599,7 +6599,7 @@ typedef struct _ATOM_FUSION_SYSTEM_INFO_V3
 typedef struct _ATOM_I2C_DATA_RECORD
 {
   UCHAR         ucNunberOfBytes;                                              //Indicates how many bytes SW needs to write to the external ASIC for one block, besides to "Start" and "Stop"
-  UCHAR         ucI2CData[1];                                                 //I2C data in bytes, should be less than 16 bytes usually
+  UCHAR         ucI2CData[];                                                  //I2C data in bytes, should be less than 16 bytes usually
 }ATOM_I2C_DATA_RECORD;
 
 
@@ -6610,14 +6610,14 @@ typedef struct _ATOM_I2C_DEVICE_SETUP_INFO
   UCHAR                              ucSSChipID;             //SS chip being used
   UCHAR                              ucSSChipSlaveAddr;      //Slave Address to set up this SS chip
   UCHAR                           ucNumOfI2CDataRecords;  //number of data block
-  ATOM_I2C_DATA_RECORD            asI2CData[1];
+  ATOM_I2C_DATA_RECORD            asI2CData[];
 }ATOM_I2C_DEVICE_SETUP_INFO;
 
 //==========================================================================================
 typedef struct  _ATOM_ASIC_MVDD_INFO
 {
   ATOM_COMMON_TABLE_HEADER         sHeader;
-  ATOM_I2C_DEVICE_SETUP_INFO      asI2CSetup[1];
+  ATOM_I2C_DEVICE_SETUP_INFO      asI2CSetup[];
 }ATOM_ASIC_MVDD_INFO;
 
 //==========================================================================================
-- 
2.37.3