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drm/amd/display: fix a UBSAN warning in DML2.1
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When programming phantom pipe, since cursor_width is explicity set to 0,
this causes calculation logic to trigger overflow for an unsigned int
triggering the kernel's UBSAN check as below:

[   40.962845] UBSAN: shift-out-of-bounds in /tmp/amd.EfpumTkO/amd/amdgpu/../display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c:3312:34
[   40.962849] shift exponent 4294967170 is too large for 32-bit type 'unsigned int'
[   40.962852] CPU: 1 PID: 1670 Comm: gnome-shell Tainted: G        W  OE      6.5.0-41-generic frank-w#41~22.04.2-Ubuntu
[   40.962854] Hardware name: Gigabyte Technology Co., Ltd. X670E AORUS PRO X/X670E AORUS PRO X, BIOS F21 01/10/2024
[   40.962856] Call Trace:
[   40.962857]  <TASK>
[   40.962860]  dump_stack_lvl+0x48/0x70
[   40.962870]  dump_stack+0x10/0x20
[   40.962872]  __ubsan_handle_shift_out_of_bounds+0x1ac/0x360
[   40.962878]  calculate_cursor_req_attributes.cold+0x1b/0x28 [amdgpu]
[   40.963099]  dml_core_mode_support+0x6b91/0x16bc0 [amdgpu]
[   40.963327]  ? srso_alias_return_thunk+0x5/0x7f
[   40.963331]  ? CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport+0x18b8/0x2790 [amdgpu]
[   40.963534]  ? srso_alias_return_thunk+0x5/0x7f
[   40.963536]  ? dml_core_mode_support+0xb3db/0x16bc0 [amdgpu]
[   40.963730]  dml2_core_calcs_mode_support_ex+0x2c/0x90 [amdgpu]
[   40.963906]  ? srso_alias_return_thunk+0x5/0x7f
[   40.963909]  ? dml2_core_calcs_mode_support_ex+0x2c/0x90 [amdgpu]
[   40.964078]  core_dcn4_mode_support+0x72/0xbf0 [amdgpu]
[   40.964247]  dml2_top_optimization_perform_optimization_phase+0x1d3/0x2a0 [amdgpu]
[   40.964420]  dml2_build_mode_programming+0x23d/0x750 [amdgpu]
[   40.964587]  dml21_validate+0x274/0x770 [amdgpu]
[   40.964761]  ? srso_alias_return_thunk+0x5/0x7f
[   40.964763]  ? resource_append_dpp_pipes_for_plane_composition+0x27c/0x3b0 [amdgpu]
[   40.964942]  dml2_validate+0x504/0x750 [amdgpu]
[   40.965117]  ? dml21_copy+0x95/0xb0 [amdgpu]
[   40.965291]  ? srso_alias_return_thunk+0x5/0x7f
[   40.965295]  dcn401_validate_bandwidth+0x4e/0x70 [amdgpu]
[   40.965491]  update_planes_and_stream_state+0x38d/0x5c0 [amdgpu]
[   40.965672]  update_planes_and_stream_v3+0x52/0x1e0 [amdgpu]
[   40.965845]  ? srso_alias_return_thunk+0x5/0x7f
[   40.965849]  dc_update_planes_and_stream+0x71/0xb0 [amdgpu]

Fix this by adding a guard for checking cursor width before triggering
the size calculation.

Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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@alexdeucher
Aurabindo Pillai authored and alexdeucher committed Aug 6, 2024
1 parent 792be2e commit eaf3adb
Showing 1 changed file with 49 additions and 44 deletions.
93 changes: 49 additions & 44 deletions drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7247,10 +7247,9 @@ static bool dml_core_mode_support(struct dml2_core_calcs_mode_support_ex *in_out
/* Cursor Support Check */
mode_lib->ms.support.CursorSupport = true;
for (k = 0; k < mode_lib->ms.num_active_planes; k++) {
if (display_cfg->plane_descriptors[k].cursor.cursor_width > 0.0) {
if (display_cfg->plane_descriptors[k].cursor.cursor_bpp == 64 && mode_lib->ip.cursor_64bpp_support == false) {
if (display_cfg->plane_descriptors[k].cursor.num_cursors > 0) {
if (display_cfg->plane_descriptors[k].cursor.cursor_bpp == 64 && mode_lib->ip.cursor_64bpp_support == false)
mode_lib->ms.support.CursorSupport = false;
}
}
}

Expand Down Expand Up @@ -8111,27 +8110,31 @@ static bool dml_core_mode_support(struct dml2_core_calcs_mode_support_ex *in_out
for (k = 0; k < mode_lib->ms.num_active_planes; ++k) {
double line_time_us = (double)display_cfg->stream_descriptors[display_cfg->plane_descriptors[k].stream_index].timing.h_total / ((double)display_cfg->stream_descriptors[display_cfg->plane_descriptors[k].stream_index].timing.pixel_clock_khz / 1000);
bool cursor_not_enough_urgent_latency_hiding = 0;
calculate_cursor_req_attributes(
display_cfg->plane_descriptors[k].cursor.cursor_width,
display_cfg->plane_descriptors[k].cursor.cursor_bpp,

// output
&s->cursor_lines_per_chunk[k],
&s->cursor_bytes_per_line[k],
&s->cursor_bytes_per_chunk[k],
&s->cursor_bytes[k]);

calculate_cursor_urgent_burst_factor(
mode_lib->ip.cursor_buffer_size,
display_cfg->plane_descriptors[k].cursor.cursor_width,
s->cursor_bytes_per_chunk[k],
s->cursor_lines_per_chunk[k],
line_time_us,
mode_lib->ms.UrgLatency,
if (display_cfg->plane_descriptors[k].cursor.num_cursors > 0) {
calculate_cursor_req_attributes(
display_cfg->plane_descriptors[k].cursor.cursor_width,
display_cfg->plane_descriptors[k].cursor.cursor_bpp,

// output
&s->cursor_lines_per_chunk[k],
&s->cursor_bytes_per_line[k],
&s->cursor_bytes_per_chunk[k],
&s->cursor_bytes[k]);

calculate_cursor_urgent_burst_factor(
mode_lib->ip.cursor_buffer_size,
display_cfg->plane_descriptors[k].cursor.cursor_width,
s->cursor_bytes_per_chunk[k],
s->cursor_lines_per_chunk[k],
line_time_us,
mode_lib->ms.UrgLatency,

// output
&mode_lib->ms.UrgentBurstFactorCursor[k],
&cursor_not_enough_urgent_latency_hiding);
}

// output
&mode_lib->ms.UrgentBurstFactorCursor[k],
&cursor_not_enough_urgent_latency_hiding);
mode_lib->ms.UrgentBurstFactorCursorPre[k] = mode_lib->ms.UrgentBurstFactorCursor[k];

#ifdef __DML_VBA_DEBUG__
Expand Down Expand Up @@ -10608,31 +10611,33 @@ static bool dml_core_mode_programming(struct dml2_core_calcs_mode_programming_ex

for (k = 0; k < s->num_active_planes; ++k) {
bool cursor_not_enough_urgent_latency_hiding = 0;
double line_time_us;
double line_time_us = 0.0;

calculate_cursor_req_attributes(
display_cfg->plane_descriptors[k].cursor.cursor_width,
display_cfg->plane_descriptors[k].cursor.cursor_bpp,
line_time_us = display_cfg->stream_descriptors[display_cfg->plane_descriptors[k].stream_index].timing.h_total /
((double)display_cfg->stream_descriptors[display_cfg->plane_descriptors[k].stream_index].timing.pixel_clock_khz / 1000);
if (display_cfg->plane_descriptors[k].cursor.num_cursors > 0) {
calculate_cursor_req_attributes(
display_cfg->plane_descriptors[k].cursor.cursor_width,
display_cfg->plane_descriptors[k].cursor.cursor_bpp,

// output
&s->cursor_lines_per_chunk[k],
&s->cursor_bytes_per_line[k],
&s->cursor_bytes_per_chunk[k],
&s->cursor_bytes[k]);

line_time_us = display_cfg->stream_descriptors[display_cfg->plane_descriptors[k].stream_index].timing.h_total / ((double)display_cfg->stream_descriptors[display_cfg->plane_descriptors[k].stream_index].timing.pixel_clock_khz / 1000);

calculate_cursor_urgent_burst_factor(
mode_lib->ip.cursor_buffer_size,
display_cfg->plane_descriptors[k].cursor.cursor_width,
s->cursor_bytes_per_chunk[k],
s->cursor_lines_per_chunk[k],
line_time_us,
mode_lib->mp.UrgentLatency,
// output
&s->cursor_lines_per_chunk[k],
&s->cursor_bytes_per_line[k],
&s->cursor_bytes_per_chunk[k],
&s->cursor_bytes[k]);

calculate_cursor_urgent_burst_factor(
mode_lib->ip.cursor_buffer_size,
display_cfg->plane_descriptors[k].cursor.cursor_width,
s->cursor_bytes_per_chunk[k],
s->cursor_lines_per_chunk[k],
line_time_us,
mode_lib->mp.UrgentLatency,

// output
&mode_lib->mp.UrgentBurstFactorCursor[k],
&cursor_not_enough_urgent_latency_hiding);
// output
&mode_lib->mp.UrgentBurstFactorCursor[k],
&cursor_not_enough_urgent_latency_hiding);
}
mode_lib->mp.UrgentBurstFactorCursorPre[k] = mode_lib->mp.UrgentBurstFactorCursor[k];

CalculateUrgentBurstFactor(
Expand Down

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