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* [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 17:25 ` Gustavo A. R. Silva
  0 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 17:25 UTC (permalink / raw)
  To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter
  Cc: amd-gfx, dri-devel, linux-kernel, Gustavo A. R. Silva, linux-hardening

Fix the following Wstringop-overflow warnings when building with GCC-11:

drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:1491:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]

by removing the over-specified array size from the argument declarations.

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/181
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 4 ++--
 drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index f11a8d97fb60..81952e07acf6 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -823,7 +823,7 @@ bool dp_is_interlane_aligned(union lane_align_status_updated align_status)
 void dp_hw_to_dpcd_lane_settings(
 		const struct link_training_settings *lt_settings,
 		const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
+		union dpcd_training_lane dpcd_lane_settings[])
 {
 	uint8_t lane = 0;
 
@@ -853,7 +853,7 @@ void dp_decide_lane_settings(
 		const struct link_training_settings *lt_settings,
 		const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
 		struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
+		union dpcd_training_lane dpcd_lane_settings[])
 {
 	uint32_t lane;
 
diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
index ab9939db8cea..0d00da1640a7 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
@@ -147,12 +147,12 @@ bool dp_is_max_vs_reached(
 void dp_hw_to_dpcd_lane_settings(
 	const struct link_training_settings *lt_settings,
 	const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
+	union dpcd_training_lane dpcd_lane_settings[]);
 void dp_decide_lane_settings(
 	const struct link_training_settings *lt_settings,
 	const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
 	struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
+	union dpcd_training_lane dpcd_lane_settings[]);
 
 uint32_t dp_translate_training_aux_read_interval(uint32_t dpcd_aux_read_interval);
 
-- 
2.27.0


^ permalink raw reply related	[flat|nested] 15+ messages in thread
* [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 17:25 ` Gustavo A. R. Silva
  0 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 17:25 UTC (permalink / raw)
  To: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter
  Cc: Gustavo A. R. Silva, linux-hardening, dri-devel, amd-gfx, linux-kernel

Fix the following Wstringop-overflow warnings when building with GCC-11:

drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:1491:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]

by removing the over-specified array size from the argument declarations.

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/181
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 4 ++--
 drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index f11a8d97fb60..81952e07acf6 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -823,7 +823,7 @@ bool dp_is_interlane_aligned(union lane_align_status_updated align_status)
 void dp_hw_to_dpcd_lane_settings(
 		const struct link_training_settings *lt_settings,
 		const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
+		union dpcd_training_lane dpcd_lane_settings[])
 {
 	uint8_t lane = 0;
 
@@ -853,7 +853,7 @@ void dp_decide_lane_settings(
 		const struct link_training_settings *lt_settings,
 		const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
 		struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
+		union dpcd_training_lane dpcd_lane_settings[])
 {
 	uint32_t lane;
 
diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
index ab9939db8cea..0d00da1640a7 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
@@ -147,12 +147,12 @@ bool dp_is_max_vs_reached(
 void dp_hw_to_dpcd_lane_settings(
 	const struct link_training_settings *lt_settings,
 	const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
+	union dpcd_training_lane dpcd_lane_settings[]);
 void dp_decide_lane_settings(
 	const struct link_training_settings *lt_settings,
 	const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
 	struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
-	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
+	union dpcd_training_lane dpcd_lane_settings[]);
 
 uint32_t dp_translate_training_aux_read_interval(uint32_t dpcd_aux_read_interval);
 
-- 
2.27.0


^ permalink raw reply related	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
  2022-03-03 17:25 ` Gustavo A. R. Silva
  (?)
@ 2022-03-03 17:43   ` Kees Cook
  -1 siblings, 0 replies; 15+ messages in thread
From: Kees Cook @ 2022-03-03 17:43 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter,
	amd-gfx, dri-devel, linux-kernel, linux-hardening

On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> Fix the following Wstringop-overflow warnings when building with GCC-11:
> 
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]

Can you "show your work" a little more here? I don't actually see the
what is getting fixed:

enum dc_lane_count {
	...
        LANE_COUNT_FOUR = 4,
	...
        LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
};

struct link_training_settings {
	...
        union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
};

void dp_hw_to_dpcd_lane_settings(
		...
		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
{
	...
}

static enum link_training_result dpia_training_cr_transparent(
		...
                struct link_training_settings *lt_settings)
{
	...
                dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
                                lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
	...
}

Everything looks to be the correct size?

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 17:43   ` Kees Cook
  0 siblings, 0 replies; 15+ messages in thread
From: Kees Cook @ 2022-03-03 17:43 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Leo Li, Pan, Xinhui, Rodrigo Siqueira, linux-kernel, amd-gfx,
	David Airlie, dri-devel, Alex Deucher, Christian König,
	linux-hardening

On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> Fix the following Wstringop-overflow warnings when building with GCC-11:
> 
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]

Can you "show your work" a little more here? I don't actually see the
what is getting fixed:

enum dc_lane_count {
	...
        LANE_COUNT_FOUR = 4,
	...
        LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
};

struct link_training_settings {
	...
        union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
};

void dp_hw_to_dpcd_lane_settings(
		...
		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
{
	...
}

static enum link_training_result dpia_training_cr_transparent(
		...
                struct link_training_settings *lt_settings)
{
	...
                dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
                                lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
	...
}

Everything looks to be the correct size?

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 17:43   ` Kees Cook
  0 siblings, 0 replies; 15+ messages in thread
From: Kees Cook @ 2022-03-03 17:43 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Leo Li, Pan, Xinhui, Rodrigo Siqueira, linux-kernel, amd-gfx,
	David Airlie, dri-devel, Daniel Vetter, Alex Deucher,
	Harry Wentland, Christian König, linux-hardening

On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> Fix the following Wstringop-overflow warnings when building with GCC-11:
> 
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]

Can you "show your work" a little more here? I don't actually see the
what is getting fixed:

enum dc_lane_count {
	...
        LANE_COUNT_FOUR = 4,
	...
        LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
};

struct link_training_settings {
	...
        union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
};

void dp_hw_to_dpcd_lane_settings(
		...
		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
{
	...
}

static enum link_training_result dpia_training_cr_transparent(
		...
                struct link_training_settings *lt_settings)
{
	...
                dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
                                lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
	...
}

Everything looks to be the correct size?

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
  2022-03-03 17:43   ` Kees Cook
  (?)
@ 2022-03-03 18:19     ` Gustavo A. R. Silva
  -1 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 18:19 UTC (permalink / raw)
  To: Kees Cook
  Cc: Leo Li, Pan, Xinhui, Rodrigo Siqueira, linux-kernel, amd-gfx,
	David Airlie, dri-devel, Alex Deucher, Christian König,
	linux-hardening

On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > 
> > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> 
> Can you "show your work" a little more here? I don't actually see the
> what is getting fixed:
> 
> enum dc_lane_count {
> 	...
>         LANE_COUNT_FOUR = 4,
> 	...
>         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> };
> 
> struct link_training_settings {
> 	...
>         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> };
> 
> void dp_hw_to_dpcd_lane_settings(
> 		...
> 		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> {
> 	...
> }
> 
> static enum link_training_result dpia_training_cr_transparent(
> 		...
>                 struct link_training_settings *lt_settings)
> {
> 	...
>                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
>                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> 	...
> }
> 
> Everything looks to be the correct size?

Yep; this fix is similar to the one for intel_pm.c in this

	commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2

where the array size of 8 seems to be fine for all the
struct members related (pri_latency, spr_latency, cur_latency
and skl_latency):

drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
...

drivers/gpu/drm/i915/i915_drv.h-739-    struct {

...
drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
drivers/gpu/drm/i915/i915_drv.h-751-            /*
drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
drivers/gpu/drm/i915/i915_drv.h-755-             */
drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];

...
drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
...
}

however GCC warns about accessing bytes beyond the limits, and turning the
argument declarations into pointers (removing the over-specified array
size from the argument declaration) silence the warnings.

--
Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 18:19     ` Gustavo A. R. Silva
  0 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 18:19 UTC (permalink / raw)
  To: Kees Cook
  Cc: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter,
	amd-gfx, dri-devel, linux-kernel, linux-hardening

On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > 
> > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> 
> Can you "show your work" a little more here? I don't actually see the
> what is getting fixed:
> 
> enum dc_lane_count {
> 	...
>         LANE_COUNT_FOUR = 4,
> 	...
>         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> };
> 
> struct link_training_settings {
> 	...
>         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> };
> 
> void dp_hw_to_dpcd_lane_settings(
> 		...
> 		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> {
> 	...
> }
> 
> static enum link_training_result dpia_training_cr_transparent(
> 		...
>                 struct link_training_settings *lt_settings)
> {
> 	...
>                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
>                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> 	...
> }
> 
> Everything looks to be the correct size?

Yep; this fix is similar to the one for intel_pm.c in this

	commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2

where the array size of 8 seems to be fine for all the
struct members related (pri_latency, spr_latency, cur_latency
and skl_latency):

drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
...

drivers/gpu/drm/i915/i915_drv.h-739-    struct {

...
drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
drivers/gpu/drm/i915/i915_drv.h-751-            /*
drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
drivers/gpu/drm/i915/i915_drv.h-755-             */
drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];

...
drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
...
}

however GCC warns about accessing bytes beyond the limits, and turning the
argument declarations into pointers (removing the over-specified array
size from the argument declaration) silence the warnings.

--
Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 18:19     ` Gustavo A. R. Silva
  0 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 18:19 UTC (permalink / raw)
  To: Kees Cook
  Cc: Leo Li, Pan, Xinhui, Rodrigo Siqueira, linux-kernel, amd-gfx,
	David Airlie, dri-devel, Daniel Vetter, Alex Deucher,
	Harry Wentland, Christian König, linux-hardening

On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > 
> > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> 
> Can you "show your work" a little more here? I don't actually see the
> what is getting fixed:
> 
> enum dc_lane_count {
> 	...
>         LANE_COUNT_FOUR = 4,
> 	...
>         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> };
> 
> struct link_training_settings {
> 	...
>         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> };
> 
> void dp_hw_to_dpcd_lane_settings(
> 		...
> 		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> {
> 	...
> }
> 
> static enum link_training_result dpia_training_cr_transparent(
> 		...
>                 struct link_training_settings *lt_settings)
> {
> 	...
>                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
>                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> 	...
> }
> 
> Everything looks to be the correct size?

Yep; this fix is similar to the one for intel_pm.c in this

	commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2

where the array size of 8 seems to be fine for all the
struct members related (pri_latency, spr_latency, cur_latency
and skl_latency):

drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
...

drivers/gpu/drm/i915/i915_drv.h-739-    struct {

...
drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
drivers/gpu/drm/i915/i915_drv.h-751-            /*
drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
drivers/gpu/drm/i915/i915_drv.h-755-             */
drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];

...
drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
...
}

however GCC warns about accessing bytes beyond the limits, and turning the
argument declarations into pointers (removing the over-specified array
size from the argument declaration) silence the warnings.

--
Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
  2022-03-03 17:25 ` Gustavo A. R. Silva
@ 2022-03-03 18:41   ` Harry Wentland
  -1 siblings, 0 replies; 15+ messages in thread
From: Harry Wentland @ 2022-03-03 18:41 UTC (permalink / raw)
  To: Gustavo A. R. Silva, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter
  Cc: amd-gfx, dri-devel, linux-kernel, linux-hardening



On 2022-03-03 12:25, Gustavo A. R. Silva wrote:
> Fix the following Wstringop-overflow warnings when building with GCC-11:
> 
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:1491:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> 
> by removing the over-specified array size from the argument declarations.
> 
> This helps with the ongoing efforts to globally enable
> -Wstringop-overflow.
> 
> Link: https://github.com/KSPP/linux/issues/181>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Acked-by: Harry Wentland <harry.wentland@amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 4 ++--
>  drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h  | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> index f11a8d97fb60..81952e07acf6 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> @@ -823,7 +823,7 @@ bool dp_is_interlane_aligned(union lane_align_status_updated align_status)
>  void dp_hw_to_dpcd_lane_settings(
>  		const struct link_training_settings *lt_settings,
>  		const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> +		union dpcd_training_lane dpcd_lane_settings[])
>  {
>  	uint8_t lane = 0;
>  
> @@ -853,7 +853,7 @@ void dp_decide_lane_settings(
>  		const struct link_training_settings *lt_settings,
>  		const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
>  		struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> +		union dpcd_training_lane dpcd_lane_settings[])
>  {
>  	uint32_t lane;
>  
> diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
> index ab9939db8cea..0d00da1640a7 100644
> --- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
> +++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
> @@ -147,12 +147,12 @@ bool dp_is_max_vs_reached(
>  void dp_hw_to_dpcd_lane_settings(
>  	const struct link_training_settings *lt_settings,
>  	const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
> +	union dpcd_training_lane dpcd_lane_settings[]);
>  void dp_decide_lane_settings(
>  	const struct link_training_settings *lt_settings,
>  	const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
>  	struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
> +	union dpcd_training_lane dpcd_lane_settings[]);
>  
>  uint32_t dp_translate_training_aux_read_interval(uint32_t dpcd_aux_read_interval);
>  


^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 18:41   ` Harry Wentland
  0 siblings, 0 replies; 15+ messages in thread
From: Harry Wentland @ 2022-03-03 18:41 UTC (permalink / raw)
  To: Gustavo A. R. Silva, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter
  Cc: linux-hardening, dri-devel, amd-gfx, linux-kernel



On 2022-03-03 12:25, Gustavo A. R. Silva wrote:
> Fix the following Wstringop-overflow warnings when building with GCC-11:
> 
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:388:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:1491:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dp.c:2613:25: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> 
> by removing the over-specified array size from the argument declarations.
> 
> This helps with the ongoing efforts to globally enable
> -Wstringop-overflow.
> 
> Link: https://github.com/KSPP/linux/issues/181>> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Acked-by: Harry Wentland <harry.wentland@amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 4 ++--
>  drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h  | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> index f11a8d97fb60..81952e07acf6 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> @@ -823,7 +823,7 @@ bool dp_is_interlane_aligned(union lane_align_status_updated align_status)
>  void dp_hw_to_dpcd_lane_settings(
>  		const struct link_training_settings *lt_settings,
>  		const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> +		union dpcd_training_lane dpcd_lane_settings[])
>  {
>  	uint8_t lane = 0;
>  
> @@ -853,7 +853,7 @@ void dp_decide_lane_settings(
>  		const struct link_training_settings *lt_settings,
>  		const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
>  		struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> +		union dpcd_training_lane dpcd_lane_settings[])
>  {
>  	uint32_t lane;
>  
> diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
> index ab9939db8cea..0d00da1640a7 100644
> --- a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
> +++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dp.h
> @@ -147,12 +147,12 @@ bool dp_is_max_vs_reached(
>  void dp_hw_to_dpcd_lane_settings(
>  	const struct link_training_settings *lt_settings,
>  	const struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
> +	union dpcd_training_lane dpcd_lane_settings[]);
>  void dp_decide_lane_settings(
>  	const struct link_training_settings *lt_settings,
>  	const union lane_adjust ln_adjust[LANE_COUNT_DP_MAX],
>  	struct dc_lane_settings hw_lane_settings[LANE_COUNT_DP_MAX],
> -	union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX]);
> +	union dpcd_training_lane dpcd_lane_settings[]);
>  
>  uint32_t dp_translate_training_aux_read_interval(uint32_t dpcd_aux_read_interval);
>  


^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
  2022-03-03 18:19     ` Gustavo A. R. Silva
  (?)
@ 2022-03-03 20:45       ` Gustavo A. R. Silva
  -1 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 20:45 UTC (permalink / raw)
  To: Kees Cook
  Cc: Harry Wentland, Leo Li, Rodrigo Siqueira, Alex Deucher,
	Christian König, Pan, Xinhui, David Airlie, Daniel Vetter,
	amd-gfx, dri-devel, linux-kernel, linux-hardening

On Thu, Mar 03, 2022 at 12:19:57PM -0600, Gustavo A. R. Silva wrote:
> On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> > On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > > 
> > > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> > 
> > Can you "show your work" a little more here? I don't actually see the
> > what is getting fixed:
> > 
> > enum dc_lane_count {
> > 	...
> >         LANE_COUNT_FOUR = 4,
> > 	...
> >         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> > };
> > 
> > struct link_training_settings {
> > 	...
> >         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> > };
> > 
> > void dp_hw_to_dpcd_lane_settings(
> > 		...
> > 		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> > {
> > 	...
> > }
> > 
> > static enum link_training_result dpia_training_cr_transparent(
> > 		...
> >                 struct link_training_settings *lt_settings)
> > {
> > 	...
> >                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
> >                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> > 	...
> > }
> > 
> > Everything looks to be the correct size?
> 
> Yep; this fix is similar to the one for intel_pm.c in this
> 
> 	commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2
> 
> where the array size of 8 seems to be fine for all the
> struct members related (pri_latency, spr_latency, cur_latency
> and skl_latency):
> 
> drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
> ...
> 
> drivers/gpu/drm/i915/i915_drv.h-739-    struct {
> 
> ...
> drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
> drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
> drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
> drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-751-            /*
> drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
> drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
> drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
> drivers/gpu/drm/i915/i915_drv.h-755-             */
> drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];
> 
> ...
> drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
> ...
> }

and in this case the ilk_wm_max_level() returns the right maximum size for the
corresponding 'struct wm' member:

drivers/gpu/drm/i915/intel_pm.c:2993:int ilk_wm_max_level(const struct drm_i915_private *dev_priv)
drivers/gpu/drm/i915/intel_pm.c-2994-{
drivers/gpu/drm/i915/intel_pm.c-2995-   /* how many WM levels are we expecting */
drivers/gpu/drm/i915/intel_pm.c-2996-   if (HAS_HW_SAGV_WM(dev_priv))
drivers/gpu/drm/i915/intel_pm.c-2997-           return 5;
drivers/gpu/drm/i915/intel_pm.c-2998-   else if (DISPLAY_VER(dev_priv) >= 9)
drivers/gpu/drm/i915/intel_pm.c-2999-           return 7;
drivers/gpu/drm/i915/intel_pm.c-3000-   else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
drivers/gpu/drm/i915/intel_pm.c-3001-           return 4;
drivers/gpu/drm/i915/intel_pm.c-3002-   else if (DISPLAY_VER(dev_priv) >= 6)
drivers/gpu/drm/i915/intel_pm.c-3003-           return 3;
drivers/gpu/drm/i915/intel_pm.c-3004-   else
drivers/gpu/drm/i915/intel_pm.c-3005-           return 2;
drivers/gpu/drm/i915/intel_pm.c-3006-}

drivers/gpu/drm/i915/intel_pm.c:3009:static void intel_print_wm_latency(struct drm_i915_private *dev_priv,
drivers/gpu/drm/i915/intel_pm.c-3010-                              const char *name,
drivers/gpu/drm/i915/intel_pm.c-3011-                              const u16 wm[])
drivers/gpu/drm/i915/intel_pm.c-3012-{
drivers/gpu/drm/i915/intel_pm.c-3013-   int level, max_level = ilk_wm_max_level(dev_priv);
drivers/gpu/drm/i915/intel_pm.c-3014-
drivers/gpu/drm/i915/intel_pm.c-3015-   for (level = 0; level <= max_level; level++) {
drivers/gpu/drm/i915/intel_pm.c-3016-           unsigned int latency = wm[level];
drivers/gpu/drm/i915/intel_pm.c-3017-
...
}

still GCC warns about this with Wstringop-overread, as it is explained
in commit e7c6e405e171.

--
Gustavo

> 
> however GCC warns about accessing bytes beyond the limits, and turning the
> argument declarations into pointers (removing the over-specified array
> size from the argument declaration) silence the warnings.
> 
> --
> Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 20:45       ` Gustavo A. R. Silva
  0 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 20:45 UTC (permalink / raw)
  To: Kees Cook
  Cc: Leo Li, Pan, Xinhui, Rodrigo Siqueira, linux-kernel, amd-gfx,
	David Airlie, dri-devel, Alex Deucher, Christian König,
	linux-hardening

On Thu, Mar 03, 2022 at 12:19:57PM -0600, Gustavo A. R. Silva wrote:
> On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> > On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > > 
> > > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> > 
> > Can you "show your work" a little more here? I don't actually see the
> > what is getting fixed:
> > 
> > enum dc_lane_count {
> > 	...
> >         LANE_COUNT_FOUR = 4,
> > 	...
> >         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> > };
> > 
> > struct link_training_settings {
> > 	...
> >         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> > };
> > 
> > void dp_hw_to_dpcd_lane_settings(
> > 		...
> > 		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> > {
> > 	...
> > }
> > 
> > static enum link_training_result dpia_training_cr_transparent(
> > 		...
> >                 struct link_training_settings *lt_settings)
> > {
> > 	...
> >                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
> >                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> > 	...
> > }
> > 
> > Everything looks to be the correct size?
> 
> Yep; this fix is similar to the one for intel_pm.c in this
> 
> 	commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2
> 
> where the array size of 8 seems to be fine for all the
> struct members related (pri_latency, spr_latency, cur_latency
> and skl_latency):
> 
> drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
> ...
> 
> drivers/gpu/drm/i915/i915_drv.h-739-    struct {
> 
> ...
> drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
> drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
> drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
> drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-751-            /*
> drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
> drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
> drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
> drivers/gpu/drm/i915/i915_drv.h-755-             */
> drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];
> 
> ...
> drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
> ...
> }

and in this case the ilk_wm_max_level() returns the right maximum size for the
corresponding 'struct wm' member:

drivers/gpu/drm/i915/intel_pm.c:2993:int ilk_wm_max_level(const struct drm_i915_private *dev_priv)
drivers/gpu/drm/i915/intel_pm.c-2994-{
drivers/gpu/drm/i915/intel_pm.c-2995-   /* how many WM levels are we expecting */
drivers/gpu/drm/i915/intel_pm.c-2996-   if (HAS_HW_SAGV_WM(dev_priv))
drivers/gpu/drm/i915/intel_pm.c-2997-           return 5;
drivers/gpu/drm/i915/intel_pm.c-2998-   else if (DISPLAY_VER(dev_priv) >= 9)
drivers/gpu/drm/i915/intel_pm.c-2999-           return 7;
drivers/gpu/drm/i915/intel_pm.c-3000-   else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
drivers/gpu/drm/i915/intel_pm.c-3001-           return 4;
drivers/gpu/drm/i915/intel_pm.c-3002-   else if (DISPLAY_VER(dev_priv) >= 6)
drivers/gpu/drm/i915/intel_pm.c-3003-           return 3;
drivers/gpu/drm/i915/intel_pm.c-3004-   else
drivers/gpu/drm/i915/intel_pm.c-3005-           return 2;
drivers/gpu/drm/i915/intel_pm.c-3006-}

drivers/gpu/drm/i915/intel_pm.c:3009:static void intel_print_wm_latency(struct drm_i915_private *dev_priv,
drivers/gpu/drm/i915/intel_pm.c-3010-                              const char *name,
drivers/gpu/drm/i915/intel_pm.c-3011-                              const u16 wm[])
drivers/gpu/drm/i915/intel_pm.c-3012-{
drivers/gpu/drm/i915/intel_pm.c-3013-   int level, max_level = ilk_wm_max_level(dev_priv);
drivers/gpu/drm/i915/intel_pm.c-3014-
drivers/gpu/drm/i915/intel_pm.c-3015-   for (level = 0; level <= max_level; level++) {
drivers/gpu/drm/i915/intel_pm.c-3016-           unsigned int latency = wm[level];
drivers/gpu/drm/i915/intel_pm.c-3017-
...
}

still GCC warns about this with Wstringop-overread, as it is explained
in commit e7c6e405e171.

--
Gustavo

> 
> however GCC warns about accessing bytes beyond the limits, and turning the
> argument declarations into pointers (removing the over-specified array
> size from the argument declaration) silence the warnings.
> 
> --
> Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-03 20:45       ` Gustavo A. R. Silva
  0 siblings, 0 replies; 15+ messages in thread
From: Gustavo A. R. Silva @ 2022-03-03 20:45 UTC (permalink / raw)
  To: Kees Cook
  Cc: Leo Li, Pan, Xinhui, Rodrigo Siqueira, linux-kernel, amd-gfx,
	David Airlie, dri-devel, Daniel Vetter, Alex Deucher,
	Harry Wentland, Christian König, linux-hardening

On Thu, Mar 03, 2022 at 12:19:57PM -0600, Gustavo A. R. Silva wrote:
> On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> > On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > > 
> > > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> > 
> > Can you "show your work" a little more here? I don't actually see the
> > what is getting fixed:
> > 
> > enum dc_lane_count {
> > 	...
> >         LANE_COUNT_FOUR = 4,
> > 	...
> >         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> > };
> > 
> > struct link_training_settings {
> > 	...
> >         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> > };
> > 
> > void dp_hw_to_dpcd_lane_settings(
> > 		...
> > 		union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> > {
> > 	...
> > }
> > 
> > static enum link_training_result dpia_training_cr_transparent(
> > 		...
> >                 struct link_training_settings *lt_settings)
> > {
> > 	...
> >                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
> >                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> > 	...
> > }
> > 
> > Everything looks to be the correct size?
> 
> Yep; this fix is similar to the one for intel_pm.c in this
> 
> 	commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2
> 
> where the array size of 8 seems to be fine for all the
> struct members related (pri_latency, spr_latency, cur_latency
> and skl_latency):
> 
> drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
> ...
> 
> drivers/gpu/drm/i915/i915_drv.h-739-    struct {
> 
> ...
> drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
> drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
> drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
> drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
> drivers/gpu/drm/i915/i915_drv.h-751-            /*
> drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
> drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
> drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
> drivers/gpu/drm/i915/i915_drv.h-755-             */
> drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];
> 
> ...
> drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
> ...
> }

and in this case the ilk_wm_max_level() returns the right maximum size for the
corresponding 'struct wm' member:

drivers/gpu/drm/i915/intel_pm.c:2993:int ilk_wm_max_level(const struct drm_i915_private *dev_priv)
drivers/gpu/drm/i915/intel_pm.c-2994-{
drivers/gpu/drm/i915/intel_pm.c-2995-   /* how many WM levels are we expecting */
drivers/gpu/drm/i915/intel_pm.c-2996-   if (HAS_HW_SAGV_WM(dev_priv))
drivers/gpu/drm/i915/intel_pm.c-2997-           return 5;
drivers/gpu/drm/i915/intel_pm.c-2998-   else if (DISPLAY_VER(dev_priv) >= 9)
drivers/gpu/drm/i915/intel_pm.c-2999-           return 7;
drivers/gpu/drm/i915/intel_pm.c-3000-   else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
drivers/gpu/drm/i915/intel_pm.c-3001-           return 4;
drivers/gpu/drm/i915/intel_pm.c-3002-   else if (DISPLAY_VER(dev_priv) >= 6)
drivers/gpu/drm/i915/intel_pm.c-3003-           return 3;
drivers/gpu/drm/i915/intel_pm.c-3004-   else
drivers/gpu/drm/i915/intel_pm.c-3005-           return 2;
drivers/gpu/drm/i915/intel_pm.c-3006-}

drivers/gpu/drm/i915/intel_pm.c:3009:static void intel_print_wm_latency(struct drm_i915_private *dev_priv,
drivers/gpu/drm/i915/intel_pm.c-3010-                              const char *name,
drivers/gpu/drm/i915/intel_pm.c-3011-                              const u16 wm[])
drivers/gpu/drm/i915/intel_pm.c-3012-{
drivers/gpu/drm/i915/intel_pm.c-3013-   int level, max_level = ilk_wm_max_level(dev_priv);
drivers/gpu/drm/i915/intel_pm.c-3014-
drivers/gpu/drm/i915/intel_pm.c-3015-   for (level = 0; level <= max_level; level++) {
drivers/gpu/drm/i915/intel_pm.c-3016-           unsigned int latency = wm[level];
drivers/gpu/drm/i915/intel_pm.c-3017-
...
}

still GCC warns about this with Wstringop-overread, as it is explained
in commit e7c6e405e171.

--
Gustavo

> 
> however GCC warns about accessing bytes beyond the limits, and turning the
> argument declarations into pointers (removing the over-specified array
> size from the argument declaration) silence the warnings.
> 
> --
> Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
  2022-03-03 20:45       ` Gustavo A. R. Silva
@ 2022-03-04 17:08         ` Alex Deucher
  -1 siblings, 0 replies; 15+ messages in thread
From: Alex Deucher @ 2022-03-04 17:08 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Kees Cook, Leo Li, Pan, Xinhui, Rodrigo Siqueira, LKML,
	amd-gfx list, David Airlie, Maling list - DRI developers,
	Daniel Vetter, Alex Deucher, Harry Wentland,
	Christian König, linux-hardening

On Thu, Mar 3, 2022 at 3:37 PM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> On Thu, Mar 03, 2022 at 12:19:57PM -0600, Gustavo A. R. Silva wrote:
> > On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> > > On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > > > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > > >
> > > > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> > >
> > > Can you "show your work" a little more here? I don't actually see the
> > > what is getting fixed:
> > >
> > > enum dc_lane_count {
> > >     ...
> > >         LANE_COUNT_FOUR = 4,
> > >     ...
> > >         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> > > };
> > >
> > > struct link_training_settings {
> > >     ...
> > >         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> > > };
> > >
> > > void dp_hw_to_dpcd_lane_settings(
> > >             ...
> > >             union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> > > {
> > >     ...
> > > }
> > >
> > > static enum link_training_result dpia_training_cr_transparent(
> > >             ...
> > >                 struct link_training_settings *lt_settings)
> > > {
> > >     ...
> > >                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
> > >                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> > >     ...
> > > }
> > >
> > > Everything looks to be the correct size?
> >
> > Yep; this fix is similar to the one for intel_pm.c in this
> >
> >       commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2
> >
> > where the array size of 8 seems to be fine for all the
> > struct members related (pri_latency, spr_latency, cur_latency
> > and skl_latency):
> >
> > drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
> > ...
> >
> > drivers/gpu/drm/i915/i915_drv.h-739-    struct {
> >
> > ...
> > drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
> > drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
> > drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
> > drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
> > drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
> > drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
> > drivers/gpu/drm/i915/i915_drv.h-751-            /*
> > drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
> > drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
> > drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
> > drivers/gpu/drm/i915/i915_drv.h-755-             */
> > drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];
> >
> > ...
> > drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
> > ...
> > }
>
> and in this case the ilk_wm_max_level() returns the right maximum size for the
> corresponding 'struct wm' member:
>
> drivers/gpu/drm/i915/intel_pm.c:2993:int ilk_wm_max_level(const struct drm_i915_private *dev_priv)
> drivers/gpu/drm/i915/intel_pm.c-2994-{
> drivers/gpu/drm/i915/intel_pm.c-2995-   /* how many WM levels are we expecting */
> drivers/gpu/drm/i915/intel_pm.c-2996-   if (HAS_HW_SAGV_WM(dev_priv))
> drivers/gpu/drm/i915/intel_pm.c-2997-           return 5;
> drivers/gpu/drm/i915/intel_pm.c-2998-   else if (DISPLAY_VER(dev_priv) >= 9)
> drivers/gpu/drm/i915/intel_pm.c-2999-           return 7;
> drivers/gpu/drm/i915/intel_pm.c-3000-   else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
> drivers/gpu/drm/i915/intel_pm.c-3001-           return 4;
> drivers/gpu/drm/i915/intel_pm.c-3002-   else if (DISPLAY_VER(dev_priv) >= 6)
> drivers/gpu/drm/i915/intel_pm.c-3003-           return 3;
> drivers/gpu/drm/i915/intel_pm.c-3004-   else
> drivers/gpu/drm/i915/intel_pm.c-3005-           return 2;
> drivers/gpu/drm/i915/intel_pm.c-3006-}
>
> drivers/gpu/drm/i915/intel_pm.c:3009:static void intel_print_wm_latency(struct drm_i915_private *dev_priv,
> drivers/gpu/drm/i915/intel_pm.c-3010-                              const char *name,
> drivers/gpu/drm/i915/intel_pm.c-3011-                              const u16 wm[])
> drivers/gpu/drm/i915/intel_pm.c-3012-{
> drivers/gpu/drm/i915/intel_pm.c-3013-   int level, max_level = ilk_wm_max_level(dev_priv);
> drivers/gpu/drm/i915/intel_pm.c-3014-
> drivers/gpu/drm/i915/intel_pm.c-3015-   for (level = 0; level <= max_level; level++) {
> drivers/gpu/drm/i915/intel_pm.c-3016-           unsigned int latency = wm[level];
> drivers/gpu/drm/i915/intel_pm.c-3017-
> ...
> }
>
> still GCC warns about this with Wstringop-overread, as it is explained
> in commit e7c6e405e171.

Did you want to respin with expanded explanation?

Alex

>
> --
> Gustavo
>
> >
> > however GCC warns about accessing bytes beyond the limits, and turning the
> > argument declarations into pointers (removing the over-specified array
> > size from the argument declaration) silence the warnings.
> >
> > --
> > Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
* Re: [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c
@ 2022-03-04 17:08         ` Alex Deucher
  0 siblings, 0 replies; 15+ messages in thread
From: Alex Deucher @ 2022-03-04 17:08 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: Kees Cook, Leo Li, Pan, Xinhui, Rodrigo Siqueira, LKML,
	amd-gfx list, David Airlie, Maling list - DRI developers,
	Alex Deucher, Christian König, linux-hardening

On Thu, Mar 3, 2022 at 3:37 PM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> On Thu, Mar 03, 2022 at 12:19:57PM -0600, Gustavo A. R. Silva wrote:
> > On Thu, Mar 03, 2022 at 09:43:28AM -0800, Kees Cook wrote:
> > > On Thu, Mar 03, 2022 at 11:25:03AM -0600, Gustavo A. R. Silva wrote:
> > > > Fix the following Wstringop-overflow warnings when building with GCC-11:
> > > >
> > > > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_link_dpia.c:493:17: warning: ‘dp_decide_lane_settings’ accessing 4 bytes in a region of size 1 [-Wstringop-overflow=]
> > >
> > > Can you "show your work" a little more here? I don't actually see the
> > > what is getting fixed:
> > >
> > > enum dc_lane_count {
> > >     ...
> > >         LANE_COUNT_FOUR = 4,
> > >     ...
> > >         LANE_COUNT_DP_MAX = LANE_COUNT_FOUR
> > > };
> > >
> > > struct link_training_settings {
> > >     ...
> > >         union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX];
> > > };
> > >
> > > void dp_hw_to_dpcd_lane_settings(
> > >             ...
> > >             union dpcd_training_lane dpcd_lane_settings[LANE_COUNT_DP_MAX])
> > > {
> > >     ...
> > > }
> > >
> > > static enum link_training_result dpia_training_cr_transparent(
> > >             ...
> > >                 struct link_training_settings *lt_settings)
> > > {
> > >     ...
> > >                 dp_decide_lane_settings(lt_settings, dpcd_lane_adjust,
> > >                                 lt_settings->hw_lane_settings, lt_settings->dpcd_lane_settings);
> > >     ...
> > > }
> > >
> > > Everything looks to be the correct size?
> >
> > Yep; this fix is similar to the one for intel_pm.c in this
> >
> >       commit e7c6e405e171fb33990a12ecfd14e6500d9e5cf2
> >
> > where the array size of 8 seems to be fine for all the
> > struct members related (pri_latency, spr_latency, cur_latency
> > and skl_latency):
> >
> > drivers/gpu/drm/i915/i915_drv.h:465:struct drm_i915_private {
> > ...
> >
> > drivers/gpu/drm/i915/i915_drv.h-739-    struct {
> >
> > ...
> > drivers/gpu/drm/i915/i915_drv.h-745-            /* primary */
> > drivers/gpu/drm/i915/i915_drv.h-746-            u16 pri_latency[5];
> > drivers/gpu/drm/i915/i915_drv.h-747-            /* sprite */
> > drivers/gpu/drm/i915/i915_drv.h-748-            u16 spr_latency[5];
> > drivers/gpu/drm/i915/i915_drv.h-749-            /* cursor */
> > drivers/gpu/drm/i915/i915_drv.h-750-            u16 cur_latency[5];
> > drivers/gpu/drm/i915/i915_drv.h-751-            /*
> > drivers/gpu/drm/i915/i915_drv.h-752-             * Raw watermark memory latency values
> > drivers/gpu/drm/i915/i915_drv.h-753-             * for SKL for all 8 levels
> > drivers/gpu/drm/i915/i915_drv.h-754-             * in 1us units.
> > drivers/gpu/drm/i915/i915_drv.h-755-             */
> > drivers/gpu/drm/i915/i915_drv.h-756-            u16 skl_latency[8];
> >
> > ...
> > drivers/gpu/drm/i915/i915_drv.h-773-    } wm;
> > ...
> > }
>
> and in this case the ilk_wm_max_level() returns the right maximum size for the
> corresponding 'struct wm' member:
>
> drivers/gpu/drm/i915/intel_pm.c:2993:int ilk_wm_max_level(const struct drm_i915_private *dev_priv)
> drivers/gpu/drm/i915/intel_pm.c-2994-{
> drivers/gpu/drm/i915/intel_pm.c-2995-   /* how many WM levels are we expecting */
> drivers/gpu/drm/i915/intel_pm.c-2996-   if (HAS_HW_SAGV_WM(dev_priv))
> drivers/gpu/drm/i915/intel_pm.c-2997-           return 5;
> drivers/gpu/drm/i915/intel_pm.c-2998-   else if (DISPLAY_VER(dev_priv) >= 9)
> drivers/gpu/drm/i915/intel_pm.c-2999-           return 7;
> drivers/gpu/drm/i915/intel_pm.c-3000-   else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
> drivers/gpu/drm/i915/intel_pm.c-3001-           return 4;
> drivers/gpu/drm/i915/intel_pm.c-3002-   else if (DISPLAY_VER(dev_priv) >= 6)
> drivers/gpu/drm/i915/intel_pm.c-3003-           return 3;
> drivers/gpu/drm/i915/intel_pm.c-3004-   else
> drivers/gpu/drm/i915/intel_pm.c-3005-           return 2;
> drivers/gpu/drm/i915/intel_pm.c-3006-}
>
> drivers/gpu/drm/i915/intel_pm.c:3009:static void intel_print_wm_latency(struct drm_i915_private *dev_priv,
> drivers/gpu/drm/i915/intel_pm.c-3010-                              const char *name,
> drivers/gpu/drm/i915/intel_pm.c-3011-                              const u16 wm[])
> drivers/gpu/drm/i915/intel_pm.c-3012-{
> drivers/gpu/drm/i915/intel_pm.c-3013-   int level, max_level = ilk_wm_max_level(dev_priv);
> drivers/gpu/drm/i915/intel_pm.c-3014-
> drivers/gpu/drm/i915/intel_pm.c-3015-   for (level = 0; level <= max_level; level++) {
> drivers/gpu/drm/i915/intel_pm.c-3016-           unsigned int latency = wm[level];
> drivers/gpu/drm/i915/intel_pm.c-3017-
> ...
> }
>
> still GCC warns about this with Wstringop-overread, as it is explained
> in commit e7c6e405e171.

Did you want to respin with expanded explanation?

Alex

>
> --
> Gustavo
>
> >
> > however GCC warns about accessing bytes beyond the limits, and turning the
> > argument declarations into pointers (removing the over-specified array
> > size from the argument declaration) silence the warnings.
> >
> > --
> > Gustavo

^ permalink raw reply	[flat|nested] 15+ messages in thread
end of thread, other threads:[~2022-03-04 17:08 UTC | newest]

Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-03 17:25 [PATCH][next] drm/amd/display: Fix Wstringop-overflow warnings in dc_link_dp.c Gustavo A. R. Silva
2022-03-03 17:25 ` Gustavo A. R. Silva
2022-03-03 17:43 ` Kees Cook
2022-03-03 17:43   ` Kees Cook
2022-03-03 17:43   ` Kees Cook
2022-03-03 18:19   ` Gustavo A. R. Silva
2022-03-03 18:19     ` Gustavo A. R. Silva
2022-03-03 18:19     ` Gustavo A. R. Silva
2022-03-03 20:45     ` Gustavo A. R. Silva
2022-03-03 20:45       ` Gustavo A. R. Silva
2022-03-03 20:45       ` Gustavo A. R. Silva
2022-03-04 17:08       ` Alex Deucher
2022-03-04 17:08         ` Alex Deucher
2022-03-03 18:41 ` Harry Wentland
2022-03-03 18:41   ` Harry Wentland

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