From: Ard Biesheuvel Date: Thu, 2 Oct 2025 21:00:45 +0000 (+0200) Subject: drm/amd/display: Fix unsafe uses of kernel mode FPU X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ddbfac152830e38d488ff8e45ab7eaf5d72f8527;p=users%2Fhch%2Fmisc.git drm/amd/display: Fix unsafe uses of kernel mode FPU The point of isolating code that uses kernel mode FPU in separate compilation units is to ensure that even implicit uses of, e.g., SIMD registers for spilling occur only in a context where this is permitted, i.e., from inside a kernel_fpu_begin/end block. This is important on arm64, which uses -mgeneral-regs-only to build all kernel code, with the exception of such compilation units where FP or SIMD registers are expected to be used. Given that the compiler may invent uses of FP/SIMD anywhere in such a unit, none of its code may be accessible from outside a kernel_fpu_begin/end block. This means that all callers into such compilation units must use the DC_FP start/end macros, which must not occur there themselves. For robustness, all functions with external linkage that reside there should call dc_assert_fp_enabled() to assert that the FPU context was set up correctly. Fix this for the DCN35, DCN351 and DCN36 implementations. Cc: Austin Zheng Cc: Jun Lei Cc: Harry Wentland Cc: Leo Li Cc: Rodrigo Siqueira Cc: Alex Deucher Cc: "Christian König" Cc: amd-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: Ard Biesheuvel Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn31/dcn31_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn31/dcn31_fpu.c index 17a21bcbde17..1a28061bb9ff 100644 --- a/drivers/gpu/drm/amd/display/dc/dml/dcn31/dcn31_fpu.c +++ b/drivers/gpu/drm/amd/display/dc/dml/dcn31/dcn31_fpu.c @@ -808,6 +808,8 @@ void dcn316_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *bw_param int dcn_get_max_non_odm_pix_rate_100hz(struct _vcs_dpi_soc_bounding_box_st *soc) { + dc_assert_fp_enabled(); + return soc->clock_limits[0].dispclk_mhz * 10000.0 / (1.0 + soc->dcn_downspread_percent / 100.0); } @@ -815,6 +817,8 @@ int dcn_get_approx_det_segs_required_for_pstate( struct _vcs_dpi_soc_bounding_box_st *soc, int pix_clk_100hz, int bpp, int seg_size_kb) { + dc_assert_fp_enabled(); + /* Roughly calculate required crb to hide latency. In practice there is slightly * more buffer available for latency hiding */ diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c index c9dd920744c9..817a370e80a7 100644 --- a/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c +++ b/drivers/gpu/drm/amd/display/dc/dml/dcn35/dcn35_fpu.c @@ -445,6 +445,8 @@ int dcn35_populate_dml_pipes_from_context_fpu(struct dc *dc, bool upscaled = false; const unsigned int max_allowed_vblank_nom = 1023; + dc_assert_fp_enabled(); + dcn31_populate_dml_pipes_from_context(dc, context, pipes, validate_mode); @@ -498,9 +500,7 @@ int dcn35_populate_dml_pipes_from_context_fpu(struct dc *dc, pipes[pipe_cnt].pipe.src.unbounded_req_mode = false; - DC_FP_START(); dcn31_zero_pipe_dcc_fraction(pipes, pipe_cnt); - DC_FP_END(); pipes[pipe_cnt].pipe.dest.vfront_porch = timing->v_front_porch; pipes[pipe_cnt].pipe.src.dcc_rate = 3; @@ -581,6 +581,8 @@ void dcn35_decide_zstate_support(struct dc *dc, struct dc_state *context) unsigned int i, plane_count = 0; DC_LOGGER_INIT(dc->ctx->logger); + dc_assert_fp_enabled(); + for (i = 0; i < dc->res_pool->pipe_count; i++) { if (context->res_ctx.pipe_ctx[i].plane_state) plane_count++; diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn351/dcn351_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn351/dcn351_fpu.c index 8cda18ce1a76..77023b619f1e 100644 --- a/drivers/gpu/drm/amd/display/dc/dml/dcn351/dcn351_fpu.c +++ b/drivers/gpu/drm/amd/display/dc/dml/dcn351/dcn351_fpu.c @@ -478,6 +478,8 @@ int dcn351_populate_dml_pipes_from_context_fpu(struct dc *dc, bool upscaled = false; const unsigned int max_allowed_vblank_nom = 1023; + dc_assert_fp_enabled(); + dcn31_populate_dml_pipes_from_context(dc, context, pipes, validate_mode); @@ -531,9 +533,7 @@ int dcn351_populate_dml_pipes_from_context_fpu(struct dc *dc, pipes[pipe_cnt].pipe.src.unbounded_req_mode = false; - DC_FP_START(); dcn31_zero_pipe_dcc_fraction(pipes, pipe_cnt); - DC_FP_END(); pipes[pipe_cnt].pipe.dest.vfront_porch = timing->v_front_porch; pipes[pipe_cnt].pipe.src.dcc_rate = 3; diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c index 07552445e424..fff57f23f4f7 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn35/dcn35_resource.c @@ -1760,6 +1760,20 @@ enum dc_status dcn35_patch_unknown_plane_state(struct dc_plane_state *plane_stat } +static int populate_dml_pipes_from_context_fpu(struct dc *dc, + struct dc_state *context, + display_e2e_pipe_params_st *pipes, + enum dc_validate_mode validate_mode) +{ + int ret; + + DC_FP_START(); + ret = dcn35_populate_dml_pipes_from_context_fpu(dc, context, pipes, validate_mode); + DC_FP_END(); + + return ret; +} + static struct resource_funcs dcn35_res_pool_funcs = { .destroy = dcn35_destroy_resource_pool, .link_enc_create = dcn35_link_encoder_create, @@ -1770,7 +1784,7 @@ static struct resource_funcs dcn35_res_pool_funcs = { .validate_bandwidth = dcn35_validate_bandwidth, .calculate_wm_and_dlg = NULL, .update_soc_for_wm_a = dcn31_update_soc_for_wm_a, - .populate_dml_pipes = dcn35_populate_dml_pipes_from_context_fpu, + .populate_dml_pipes = populate_dml_pipes_from_context_fpu, .acquire_free_pipe_as_secondary_dpp_pipe = dcn20_acquire_free_pipe_for_layer, .release_pipe = dcn20_release_pipe, .add_stream_to_ctx = dcn30_add_stream_to_ctx, diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c index cb0478a9a34d..0abd163b425e 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn351/dcn351_resource.c @@ -1732,6 +1732,21 @@ static enum dc_status dcn351_validate_bandwidth(struct dc *dc, return out ? DC_OK : DC_FAIL_BANDWIDTH_VALIDATE; } +static int populate_dml_pipes_from_context_fpu(struct dc *dc, + struct dc_state *context, + display_e2e_pipe_params_st *pipes, + enum dc_validate_mode validate_mode) +{ + int ret; + + DC_FP_START(); + ret = dcn351_populate_dml_pipes_from_context_fpu(dc, context, pipes, validate_mode); + DC_FP_END(); + + return ret; + +} + static struct resource_funcs dcn351_res_pool_funcs = { .destroy = dcn351_destroy_resource_pool, .link_enc_create = dcn35_link_encoder_create, @@ -1742,7 +1757,7 @@ static struct resource_funcs dcn351_res_pool_funcs = { .validate_bandwidth = dcn351_validate_bandwidth, .calculate_wm_and_dlg = NULL, .update_soc_for_wm_a = dcn31_update_soc_for_wm_a, - .populate_dml_pipes = dcn351_populate_dml_pipes_from_context_fpu, + .populate_dml_pipes = populate_dml_pipes_from_context_fpu, .acquire_free_pipe_as_secondary_dpp_pipe = dcn20_acquire_free_pipe_for_layer, .release_pipe = dcn20_release_pipe, .add_stream_to_ctx = dcn30_add_stream_to_ctx, diff --git a/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c b/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c index 126090c9bb8a..ca125ee6c2fb 100644 --- a/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c +++ b/drivers/gpu/drm/amd/display/dc/resource/dcn36/dcn36_resource.c @@ -1734,6 +1734,20 @@ static enum dc_status dcn35_validate_bandwidth(struct dc *dc, } +static int populate_dml_pipes_from_context_fpu(struct dc *dc, + struct dc_state *context, + display_e2e_pipe_params_st *pipes, + enum dc_validate_mode validate_mode) +{ + int ret; + + DC_FP_START(); + ret = dcn35_populate_dml_pipes_from_context_fpu(dc, context, pipes, validate_mode); + DC_FP_END(); + + return ret; +} + static struct resource_funcs dcn36_res_pool_funcs = { .destroy = dcn36_destroy_resource_pool, .link_enc_create = dcn35_link_encoder_create, @@ -1744,7 +1758,7 @@ static struct resource_funcs dcn36_res_pool_funcs = { .validate_bandwidth = dcn35_validate_bandwidth, .calculate_wm_and_dlg = NULL, .update_soc_for_wm_a = dcn31_update_soc_for_wm_a, - .populate_dml_pipes = dcn35_populate_dml_pipes_from_context_fpu, + .populate_dml_pipes = populate_dml_pipes_from_context_fpu, .acquire_free_pipe_as_secondary_dpp_pipe = dcn20_acquire_free_pipe_for_layer, .release_pipe = dcn20_release_pipe, .add_stream_to_ctx = dcn30_add_stream_to_ctx,