linux-kernel - [PATCH 3/4] drm/amd/display: avoid large on-stack structures

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Date: Tue, 28 May 2024 13:51:20 +0200
From: Arnd Bergmann <arnd@...nel.org>
To: Harry Wentland <harry.wentland@....com>,
	Leo Li <sunpeng.li@....com>,
	Rodrigo Siqueira <Rodrigo.Siqueira@....com>
Cc: Arnd Bergmann <arnd@...db.de>,
	Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>,
	"Pan, Xinhui" <Xinhui.Pan@....com>,
	David Airlie <airlied@...il.com>,
	Daniel Vetter <daniel@...ll.ch>,
	Dillon Varone <dillon.varone@....com>,
	Alex Hung <alex.hung@....com>,
	Chaitanya Dhere <chaitanya.dhere@....com>,
	Alvin Lee <alvin.lee2@....com>,
	Joshua Aberback <joshua.aberback@....com>,
	Charlene Liu <charlene.liu@....com>,
	Mario Limonciello <mario.limonciello@....com>,
	Wenjing Liu <wenjing.liu@....com>,
	Aurabindo Pillai <aurabindo.pillai@....com>,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] drm/amd/display: avoid large on-stack structures

From: Arnd Bergmann <arnd@...db.de>

Putting excessively large objects on a function stack causes
a warning about possibly overflowing the 8KiB of kernel stack:

drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn401/dcn401_resource.c: In function 'dcn401_update_bw_bounding_box':
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn401/dcn401_resource.c:1599:1: error: the frame size of 1196 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
 1599 | }
      | ^
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_state.c: In function 'dc_state_create':
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_state.c:221:1: error: the frame size of 1196 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
  221 | }
      | ^

Use dynamic allocation instead.

Fixes: e779f4587f61 ("drm/amd/display: Add handling for DC power mode")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/gpu/drm/amd/display/dc/core/dc_state.c   | 16 +++++++++++-----
 .../display/dc/resource/dcn401/dcn401_resource.c | 16 +++++++++++-----
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_state.c b/drivers/gpu/drm/amd/display/dc/core/dc_state.c
index 70928223b642..8ea9391c60b7 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_state.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_state.c
@@ -193,7 +193,11 @@ static void init_state(struct dc *dc, struct dc_state *state)
 struct dc_state *dc_state_create(struct dc *dc, struct dc_state_create_params *params)
 {
 #ifdef CONFIG_DRM_AMD_DC_FP
-	struct dml2_configuration_options dml2_opt = dc->dml2_options;
+	struct dml2_configuration_options *dml2_opt;
+
+	dml2_opt = kmemdup(&dc->dml2_options, sizeof(*dml2_opt), GFP_KERNEL);
+	if (!dml2_opt)
+		return NULL;
 #endif
 	struct dc_state *state = kvzalloc(sizeof(struct dc_state),
 			GFP_KERNEL);
@@ -207,12 +211,14 @@ struct dc_state *dc_state_create(struct dc *dc, struct dc_state_create_params *p
 
 #ifdef CONFIG_DRM_AMD_DC_FP
 	if (dc->debug.using_dml2) {
-		dml2_opt.use_clock_dc_limits = false;
-		dml2_create(dc, &dml2_opt, &state->bw_ctx.dml2);
+		dml2_opt->use_clock_dc_limits = false;
+		dml2_create(dc, dml2_opt, &state->bw_ctx.dml2);
 
-		dml2_opt.use_clock_dc_limits = true;
-		dml2_create(dc, &dml2_opt, &state->bw_ctx.dml2_dc_power_source);
+		dml2_opt->use_clock_dc_limits = true;
+		dml2_create(dc, dml2_opt, &state->bw_ctx.dml2_dc_power_source);
 	}
+
+	kfree(dml2_opt);
 #endif
 
 	kref_init(&state->refcount);
diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c
index 247bac177d1b..8dfb0a3d21cb 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn401/dcn401_resource.c
@@ -1581,21 +1581,27 @@ static struct dc_cap_funcs cap_funcs = {
 
 static void dcn401_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *bw_params)
 {
-	struct dml2_configuration_options dml2_opt = dc->dml2_options;
+	struct dml2_configuration_options *dml2_opt;
+
+	dml2_opt = kmemdup(&dc->dml2_options, sizeof(*dml2_opt), GFP_KERNEL);
+	if (!dml2_opt)
+		return;
 
 	DC_FP_START();
 
 	dcn401_update_bw_bounding_box_fpu(dc, bw_params);
 
-	dml2_opt.use_clock_dc_limits = false;
+	dml2_opt->use_clock_dc_limits = false;
 	if (dc->debug.using_dml2 && dc->current_state && dc->current_state->bw_ctx.dml2)
-		dml2_reinit(dc, &dml2_opt, &dc->current_state->bw_ctx.dml2);
+		dml2_reinit(dc, dml2_opt, &dc->current_state->bw_ctx.dml2);
 
-	dml2_opt.use_clock_dc_limits = true;
+	dml2_opt->use_clock_dc_limits = true;
 	if (dc->debug.using_dml2 && dc->current_state && dc->current_state->bw_ctx.dml2_dc_power_source)
-		dml2_reinit(dc, &dml2_opt, &dc->current_state->bw_ctx.dml2_dc_power_source);
+		dml2_reinit(dc, dml2_opt, &dc->current_state->bw_ctx.dml2_dc_power_source);
 
 	DC_FP_END();
+
+	kfree(dml2_opt);
 }
 
 enum dc_status dcn401_patch_unknown_plane_state(struct dc_plane_state *plane_state)
-- 
2.39.2