On 2017-12-04 08:08 AM, Arnd Bergmann wrote: > Building the DCN 1.0 Raven display driver with CONFIG_KCOV_INSTRUMENT_ALL=y > and CONFIG_KCOV_ENABLE_COMPARISONS=y results in warnings about many functions > that do a comparison of floating-point variables: > > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `dcn_bw_calc_rq_dlg_ttu': > dcn_calcs.c:(.text+0x263): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `hack_force_pipe_split': > dcn_calcs.c:(.text+0x155b): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `dcn_find_dcfclk_suits_all': > dcn_calcs.c:(.text+0x190e): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.o: In function `dcn_validate_bandwidth': > dcn_calcs.c:(.text+0xe121): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_bw_mod': > dcn_calc_math.c:(.text+0x22): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_bw_min2': > dcn_calc_math.c:(.text+0xb2): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_bw_ceil2': > dcn_calc_math.c:(.text+0x2a0): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_bw_max3': > dcn_calc_math.c:(.text+0x325): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_bw_max5': > dcn_calc_math.c:(.text+0x3c3): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_math.o: In function `dcn_bw_log': > dcn_calc_math.c:(.text+0x54e): undefined reference to `__sanitizer_cov_trace_cmpd' > dcn_calc_math.c:(.text+0x57c): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `scaler_settings_calculation': > dcn_calc_auto.c:(.text+0x5c5): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode_support_and_system_configuration': > dcn_calc_auto.c:(.text+0x137c): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode_support_and_system_configuration': > dcn_calc_auto.c:(.text+0x9233): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode_support_and_system_configuration': > dcn_calc_auto.c:(.text+0xb70f): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `mode_support_and_system_configuration': > dcn_calc_auto.c:(.text+0x121fd): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `display_pipe_configuration': > dcn_calc_auto.c:(.text+0x15a2f): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `dispclkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_calculation': > dcn_calc_auto.c:(.text+0x17c2d): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `dispclkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_calculation': > dcn_calc_auto.c:(.text+0x19362): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `dispclkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_calculation': > dcn_calc_auto.c:(.text+0x25575): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/calcs/dcn_calc_auto.o: In function `dispclkdppclkdcfclk_deep_sleep_prefetch_parameters_watermarks_and_performance_calculation': > dcn_calc_auto.c:(.text+0x27f33): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/display_rq_dlg_calc.o: In function `get_refcyc_per_delivery': > display_rq_dlg_calc.c:(.text+0xb5): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/display_rq_dlg_calc.o: In function `calculate_ttu_cursor.isra.1': > display_rq_dlg_calc.c:(.text+0x9f6): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/display_rq_dlg_calc.o: In function `dml_rq_dlg_get_dlg_params': > display_rq_dlg_calc.c:(.text+0x82cc): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In function `get_refcyc_per_delivery.isra.0': > dml1_display_rq_dlg_calc.c:(.text+0x6c4): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In function `get_vratio_pre.isra.2': > dml1_display_rq_dlg_calc.c:(.text+0x957): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In function `get_swath_need.isra.3': > dml1_display_rq_dlg_calc.c:(.text+0xc8e): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In function `dml1_extract_rq_regs': > dml1_display_rq_dlg_calc.c:(.text+0x30a8): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In function `dml1_rq_dlg_get_dlg_params': > dml1_display_rq_dlg_calc.c:(.text+0x41ee): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/dml1_display_rq_dlg_calc.o: In function `dml1_rq_dlg_get_dlg_params': > dml1_display_rq_dlg_calc.c:(.text+0x8f95): undefined reference to `__sanitizer_cov_trace_cmpf' > drivers/gpu/drm/amd/display/dc/dml/dml_common_defs.o: In function `dml_round': > dml_common_defs.c:(.text+0x77): undefined reference to `__sanitizer_cov_trace_cmpd' > drivers/gpu/drm/amd/display/dc/dml/display_mode_vba.o: In function `adjust_ReturnBW': > display_mode_vba.c:(.text+0x4490): undefined reference to `__sanitizer_cov_trace_cmpd' > Is this with clang? I don't seem to get these with gcc. > We already prevent the driver from being built on non-x86 architectures > because of its use of floating-point arithmetic, this extends the > dependency to also cover Kcov-enabled builds, which arguably is a much > more severe limitation. > > I tried implementing the two functions in KCOV: __sanitizer_cov_trace_cmpd > and __sanitizer_cov_trace_cmpf, but that fails to build on architectures > that do not support any floating-point functions, or would require making > that code x86 specific as well. I also looked at what it would take to > convert the code to fixed-point arithmetic, but quickly gave up. This > is probably the right approach, but it requires a non-trivial amount of > work and certainly won't be appropriate as a bugfix. > > Fixes: bf2e2e2e0ea9 ("drm/amd/display: Limit DCN to x86 arch") > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > drivers/gpu/drm/amd/display/Kconfig | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/display/Kconfig > index ec3285f65517..5cd5906c9bee 100644 > --- a/drivers/gpu/drm/amd/display/Kconfig > +++ b/drivers/gpu/drm/amd/display/Kconfig > @@ -30,6 +30,8 @@ config DRM_AMD_DC_FBC > config DRM_AMD_DC_DCN1_0 > bool "DCN 1.0 Raven family" > depends on DRM_AMD_DC && X86 > + # x86 floating point math here breaks with KCOV: > + depends on !(KCOV_INSTRUMENT_ALL && KCOV_ENABLE_COMPARISONS) || BROKEN I don't think it makes sense to make this depend on BROKEN as it works and is quite useful to people with Raven systems. Harry > help > Choose this option if you want to have > RV family for display engine > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel