Hi Tzung-Bi, First of all, thanks for the patch! On Thu, Jan 09, 2025 at 05:35:04AM +0000, Tzung-Bi Shih wrote: > When compiling allmodconfig (CONFIG_WERROR=y) with clang-19, see the > following errors: > > .../display/dc/dml2/display_mode_core.c:6268:13: warning: stack frame size (3128) exceeds limit (3072) in 'dml_prefetch_check' [-Wframe-larger-than] > .../display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c:7236:13: warning: stack frame size (3256) exceeds limit (3072) in 'dml_core_mode_support' [-Wframe-larger-than] > > Mark static functions called by dml_prefetch_check() and > dml_core_mode_support() noinline_for_stack to avoid them become huge > functions and thus exceed the frame size limit. So I fixed these particular instances by hiding them when certain sanitizers are enabled: https://gitlab.freedesktop.org/agd5f/linux/-/commit/e4479aecf6581af81bc0908575447878d2a07e01 However, there are still reports of the regular 2048 limit being hit with certain configurations such as LTO (the issue number is somewhat funny given the situation): https://github.com/ClangBuiltLinux/linux/issues/2048 So I think it would be a good idea for the AMD folks to consider applying this patch as well. > A way to reproduce: > $ git checkout next-20250107 > $ mkdir build_dir > $ export PATH=/tmp/llvm-19.1.6-x86_64/bin:$PATH > $ make LLVM=1 O=build_dir allmodconfig > $ make LLVM=1 O=build_dir drivers/gpu/drm/ -j > > The way how it chose static functions to mark: > [0] Unset CONFIG_WERROR in build_dir/.config. > To get display_mode_core.o without errors. > > [1] Get a function list called by dml_prefetch_check(). > $ sed -n '6268,6711p' drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c \ > | sed -n -r 's/.*\W(\w+)\(.*/\1/p' | sort -u >/tmp/syms > > [2] Get the non-inline function list. > Objdump won't show the symbols if they are inline functions. > > $ make LLVM=1 O=build_dir drivers/gpu/drm/ -j > $ objdump -d build_dir/.../display_mode_core.o | \ > ./scripts/checkstack.pl x86_64 0 | \ > grep -f /tmp/syms | cut -d' ' -f2- >/tmp/orig > > [3] Get the full function list. > Append "-fno-inline" to `CFLAGS_.../display_mode_core.o` in > drivers/gpu/drm/amd/display/dc/dml2/Makefile. > > $ make LLVM=1 O=build_dir drivers/gpu/drm/ -j > $ objdump -d build_dir/.../display_mode_core.o | \ > ./scripts/checkstack.pl x86_64 0 | \ > grep -f /tmp/syms | cut -d' ' -f2- >/tmp/noinline > > [4] Get the inline function list. > If a symbol only in /tmp/noinline but not in /tmp/orig, it is a good > candidate to mark noinline. > > $ diff /tmp/orig /tmp/noinline > > Chosen functions and their stack sizes: > CalculateBandwidthAvailableForImmediateFlip [display_mode_core.o]:144 > CalculateExtraLatency [display_mode_core.o]:176 > CalculateTWait [display_mode_core.o]:64 > CalculateVActiveBandwithSupport [display_mode_core.o]:112 > set_calculate_prefetch_schedule_params [display_mode_core.o]:48 > > CheckGlobalPrefetchAdmissibility [dml2_core_dcn4_calcs.o]:544 > calculate_bandwidth_available [dml2_core_dcn4_calcs.o]:320 > calculate_vactive_det_fill_latency [dml2_core_dcn4_calcs.o]:272 > CalculateDCFCLKDeepSleep [dml2_core_dcn4_calcs.o]:208 > CalculateODMMode [dml2_core_dcn4_calcs.o]:208 > CalculateOutputLink [dml2_core_dcn4_calcs.o]:176 > > Signed-off-by: Tzung-Bi Shih <tzungbi@xxxxxxxxxx> > --- > .../gpu/drm/amd/display/dc/dml2/display_mode_core.c | 12 ++++++------ > .../dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c | 12 ++++++------ > 2 files changed, 12 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c b/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c > index 35bc917631ae..84a2de9a76d4 100644 > --- a/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c > +++ b/drivers/gpu/drm/amd/display/dc/dml2/display_mode_core.c > @@ -1736,7 +1736,7 @@ static void CalculateBytePerPixelAndBlockSizes( > #endif > } // CalculateBytePerPixelAndBlockSizes > > -static dml_float_t CalculateTWait( > +static noinline_for_stack dml_float_t CalculateTWait( > dml_uint_t PrefetchMode, > enum dml_use_mall_for_pstate_change_mode UseMALLForPStateChange, > dml_bool_t SynchronizeDRRDisplaysForUCLKPStateChangeFinal, > @@ -4458,7 +4458,7 @@ static void CalculateSwathWidth( > } > } // CalculateSwathWidth > > -static dml_float_t CalculateExtraLatency( > +static noinline_for_stack dml_float_t CalculateExtraLatency( > dml_uint_t RoundTripPingLatencyCycles, > dml_uint_t ReorderingBytes, > dml_float_t DCFCLK, > @@ -5915,7 +5915,7 @@ static dml_uint_t DSCDelayRequirement( > return DSCDelayRequirement_val; > } > > -static dml_bool_t CalculateVActiveBandwithSupport(dml_uint_t NumberOfActiveSurfaces, > +static noinline_for_stack dml_bool_t CalculateVActiveBandwithSupport(dml_uint_t NumberOfActiveSurfaces, > dml_float_t ReturnBW, > dml_bool_t NotUrgentLatencyHiding[], > dml_float_t ReadBandwidthLuma[], > @@ -6019,7 +6019,7 @@ static void CalculatePrefetchBandwithSupport( > #endif > } > > -static dml_float_t CalculateBandwidthAvailableForImmediateFlip( > +static noinline_for_stack dml_float_t CalculateBandwidthAvailableForImmediateFlip( > dml_uint_t NumberOfActiveSurfaces, > dml_float_t ReturnBW, > dml_float_t ReadBandwidthLuma[], > @@ -6213,7 +6213,7 @@ static dml_uint_t CalculateMaxVStartup( > return max_vstartup_lines; > } > > -static void set_calculate_prefetch_schedule_params(struct display_mode_lib_st *mode_lib, > +static noinline_for_stack void set_calculate_prefetch_schedule_params(struct display_mode_lib_st *mode_lib, > struct CalculatePrefetchSchedule_params_st *CalculatePrefetchSchedule_params, > dml_uint_t j, > dml_uint_t k) > @@ -6265,7 +6265,7 @@ static void set_calculate_prefetch_schedule_params(struct display_mode_lib_st *m > CalculatePrefetchSchedule_params->Tno_bw = &mode_lib->ms.Tno_bw[k]; > } > > -static void dml_prefetch_check(struct display_mode_lib_st *mode_lib) > +static noinline_for_stack void dml_prefetch_check(struct display_mode_lib_st *mode_lib) > { > struct dml_core_mode_support_locals_st *s = &mode_lib->scratch.dml_core_mode_support_locals; > struct CalculatePrefetchSchedule_params_st *CalculatePrefetchSchedule_params = &mode_lib->scratch.CalculatePrefetchSchedule_params; > diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c > index b9ec243cf9ba..7fffca67ca9d 100644 > --- a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c > +++ b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_core/dml2_core_dcn4_calcs.c > @@ -2778,7 +2778,7 @@ static double dml_get_return_bandwidth_available( > return return_bw_mbps; > } > > -static void calculate_bandwidth_available( > +static noinline_for_stack void calculate_bandwidth_available( > double avg_bandwidth_available_min[dml2_core_internal_soc_state_max], > double avg_bandwidth_available[dml2_core_internal_soc_state_max][dml2_core_internal_bw_max], > double urg_bandwidth_available_min[dml2_core_internal_soc_state_max], // min between SDP and DRAM > @@ -3531,7 +3531,7 @@ static void CalculateUrgentBurstFactor( > > } > > -static void CalculateDCFCLKDeepSleep( > +static noinline_for_stack void CalculateDCFCLKDeepSleep( > const struct dml2_display_cfg *display_cfg, > unsigned int NumberOfActiveSurfaces, > unsigned int BytePerPixelY[], > @@ -4076,7 +4076,7 @@ static bool ValidateODMMode(enum dml2_odm_mode ODMMode, > return true; > } > > -static void CalculateODMMode( > +static noinline_for_stack void CalculateODMMode( > unsigned int MaximumPixelsPerLinePerDSCUnit, > unsigned int HActive, > enum dml2_output_format_class OutFormat, > @@ -4173,7 +4173,7 @@ static void CalculateODMMode( > #endif > } > > -static void CalculateOutputLink( > +static noinline_for_stack void CalculateOutputLink( > struct dml2_core_internal_scratch *s, > double PHYCLK, > double PHYCLKD18, > @@ -5928,7 +5928,7 @@ static double calculate_impacted_Tsw(unsigned int exclude_plane_idx, unsigned in > } > > // a global check against the aggregate effect of the per plane prefetch schedule > -static bool CheckGlobalPrefetchAdmissibility(struct dml2_core_internal_scratch *scratch, > +static noinline_for_stack bool CheckGlobalPrefetchAdmissibility(struct dml2_core_internal_scratch *scratch, > struct dml2_core_calcs_CheckGlobalPrefetchAdmissibility_params *p) > { > struct dml2_core_calcs_CheckGlobalPrefetchAdmissibility_locals *s = &scratch->CheckGlobalPrefetchAdmissibility_locals; > @@ -6941,7 +6941,7 @@ static void calculate_bytes_to_fetch_required_to_hide_latency( > } > } > > -static void calculate_vactive_det_fill_latency( > +static noinline_for_stack void calculate_vactive_det_fill_latency( > const struct dml2_display_cfg *display_cfg, > unsigned int num_active_planes, > unsigned int bytes_required_l[], > -- > 2.47.1.613.gc27f4b7a9f-goog >
