releases/5.4.285/drm-amdgpu-replace-one-element-array-with-flexible-a.patch

From 25ea5a34abadb9fccc9ce2cc812d7425addddbe3 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Sat, 29 Oct 2022 14:30:44 +1300
Subject: drm/amdgpu: Replace one-element array with flexible-array member

From: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>

[ Upstream commit 320e2590e281d0a7865e861f50155b5b435e9813 ]

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 struct _ATOM_FAKE_EDID_PATCH_RECORD and
refactor the rest of the code accordingly.

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>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Stable-dep-of: 8155566a26b8 ("drm/amdgpu: properly handle vbios fake edid sizing")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/atombios_encoders.c | 7 +++++--
 drivers/gpu/drm/amd/include/atombios.h         | 2 +-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c b/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
index 1e94a9b652f70..754d1e1387155 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
@@ -2113,8 +2113,11 @@ amdgpu_atombios_encoder_get_lcd_info(struct amdgpu_encoder *encoder)
 						}
 					}
 					record += fake_edid_record->ucFakeEDIDLength ?
-						fake_edid_record->ucFakeEDIDLength + 2 :
-						sizeof(ATOM_FAKE_EDID_PATCH_RECORD);
+						  struct_size(fake_edid_record,
+							      ucFakeEDIDString,
+							      fake_edid_record->ucFakeEDIDLength) :
+						  /* empty fake edid record must be 3 bytes long */
+						  sizeof(ATOM_FAKE_EDID_PATCH_RECORD) + 1;
 					break;
 				case LCD_PANEL_RESOLUTION_RECORD_TYPE:
 					panel_res_record = (ATOM_PANEL_RESOLUTION_PATCH_RECORD *)record;
diff --git a/drivers/gpu/drm/amd/include/atombios.h b/drivers/gpu/drm/amd/include/atombios.h
index 8ba21747b40a3..c9f70accd46d8 100644
--- a/drivers/gpu/drm/amd/include/atombios.h
+++ b/drivers/gpu/drm/amd/include/atombios.h
@@ -4107,7 +4107,7 @@ typedef struct _ATOM_FAKE_EDID_PATCH_RECORD
 {
   UCHAR ucRecordType;
   UCHAR ucFakeEDIDLength;       // = 128 means EDID length is 128 bytes, otherwise the EDID length = ucFakeEDIDLength*128
-  UCHAR ucFakeEDIDString[1];    // This actually has ucFakeEdidLength elements.
+  UCHAR ucFakeEDIDString[];     // This actually has ucFakeEdidLength elements.
 } ATOM_FAKE_EDID_PATCH_RECORD;
 
 typedef struct  _ATOM_PANEL_RESOLUTION_PATCH_RECORD
-- 
2.43.0