[PATCH AUTOSEL 6.11 192/244] drm/amd/display: Fix possible overflow in integer multiplication

Sasha Levin
2024-09-25T11:50:03Z

From: Alex Hung <alex.hung@amd.com>

[ Upstream commit 3f96f545f877ac59d0c967f52d760b4b2b3b9a47 ]

[WHAT & HOW]
Integer multiplies integer may overflow in context that expects an
expression of unsigned long long (64 bits). This can be fixed by casting
integer to unsigned long long to force 64 bits results.

This fixes 2 OVERFLOW_BEFORE_WIDEN issues reported by Coverity.

Signed-off-by: Alex Hung <alex.hung@amd.com>
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../amd/display/dc/resource/dcn32/dcn32_resource_helpers.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c
index 47c8a9fbe7546..f5a4e97c40ced 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c
+++ b/drivers/gpu/drm/amd/display/dc/resource/dcn32/dcn32_resource_helpers.c
@@ -663,7 +663,7 @@ bool dcn32_subvp_drr_admissable(struct dc *dc, struct dc_state *context)

subvp_disallow |= disallow_subvp_in_active_plus_blank(pipe);
refresh_rate = (pipe->stream->timing.pix_clk_100hz * (uint64_t)100 +
- pipe->stream->timing.v_total * pipe->stream->timing.h_total - (uint64_t)1);
+ pipe->stream->timing.v_total * (unsigned long long)pipe->stream->timing.h_total - (uint64_t)1);
refresh_rate = div_u64(refresh_rate, pipe->stream->timing.v_total);
refresh_rate = div_u64(refresh_rate, pipe->stream->timing.h_total);
}
@@ -724,7 +724,7 @@ bool dcn32_subvp_vblank_admissable(struct dc *dc, struct dc_state *context, int

subvp_disallow |= disallow_subvp_in_active_plus_blank(pipe);
refresh_rate = (pipe->stream->timing.pix_clk_100hz * (uint64_t)100 +
- pipe->stream->timing.v_total * pipe->stream->timing.h_total - (uint64_t)1);
+ pipe->stream->timing.v_total * (unsigned long long)pipe->stream->timing.h_total - (uint64_t)1);
refresh_rate = div_u64(refresh_rate, pipe->stream->timing.v_total);
refresh_rate = div_u64(refresh_rate, pipe->stream->timing.h_total);
}
--
2.43.0