| Message ID | 20190712093720.1461418-1-arnd@arndb.de |
|---|---|
| State | Accepted |
| Commit | 7e446b3c76b4ef0d3808305c0a51f895236b37bf |
| Headers | show |
| Series | drm/amd/display: Support clang option for stack alignment | expand |
On Fri, Jul 12, 2019 at 8:49 PM 'Nick Desaulniers' via Clang Built Linux <clang-built-linux@googlegroups.com> wrote: > > On Fri, Jul 12, 2019 at 2:37 AM Arnd Bergmann <arnd@arndb.de> wrote: > > > > As previously fixed for dml in commit 4769278e5c7f ("amdgpu/dc/dml: > > Support clang option for stack alignment") and calcs in commit > > cc32ad8f559c ("amdgpu/dc/calcs: Support clang option for stack > > alignment"), dcn20 uses an option that is not available with clang: > > > > clang: error: unknown argument: '-mpreferred-stack-boundary=4' > > scripts/Makefile.build:281: recipe for target 'drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_resource.o' failed > > > > Use the same trick that we have in the other two files. > > Maybe time for a macro in Kbuild.include or some such, if we see this > pattern being repeated? I'm not actually convinced that the argument does anything useful at all, if the kernel stack is normally not 16-byte aligned when we enter the driver, and it clearly is not needed if the stack is already aligned. Unless any code calling into the portions that want the alignment manually aligns the kernel stack pointer, we could just as well leave it out. The git history does not explain why it was added in the first place though, so I really have no idea. I see in the architecture makefiles that i386 kernels are built with the same flag globally, but other architectures (including x86_64) use the default stack alignment, which may be different. Arnd
diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile index 1b68de27ba74..e9721a906592 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile @@ -10,7 +10,13 @@ ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT DCN20 += dcn20_dsc.o endif -CFLAGS_dcn20_resource.o := -mhard-float -msse -mpreferred-stack-boundary=4 +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) + cc_stack_align := -mpreferred-stack-boundary=4 +else ifneq ($(call cc-option, -mstack-alignment=16),) + cc_stack_align := -mstack-alignment=16 +endif + +CFLAGS_dcn20_resource.o := -mhard-float -msse $(cc_stack_align) AMD_DAL_DCN20 = $(addprefix $(AMDDALPATH)/dc/dcn20/,$(DCN20)) diff --git a/drivers/gpu/drm/amd/display/dc/dsc/Makefile b/drivers/gpu/drm/amd/display/dc/dsc/Makefile index c5d5b94e2604..e019cd9447e8 100644 --- a/drivers/gpu/drm/amd/display/dc/dsc/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dsc/Makefile @@ -1,10 +1,18 @@ # # Makefile for the 'dsc' sub-component of DAL. -CFLAGS_rc_calc.o := -mhard-float -msse -mpreferred-stack-boundary=4 -CFLAGS_rc_calc_dpi.o := -mhard-float -msse -mpreferred-stack-boundary=4 -CFLAGS_codec_main_amd.o := -mhard-float -msse -mpreferred-stack-boundary=4 -CFLAGS_dc_dsc.o := -mhard-float -msse -mpreferred-stack-boundary=4 +ifneq ($(call cc-option, -mpreferred-stack-boundary=4),) + cc_stack_align := -mpreferred-stack-boundary=4 +else ifneq ($(call cc-option, -mstack-alignment=16),) + cc_stack_align := -mstack-alignment=16 +endif + +dsc_ccflags := -mhard-float -msse $(cc_stack_align) + +CFLAGS_rc_calc.o := $(dsc_ccflags) +CFLAGS_rc_calc_dpi.o := $(dsc_ccflags) +CFLAGS_codec_main_amd.o := $(dsc_ccflags) +CFLAGS_dc_dsc.o := $(dsc_ccflags) DSC = dc_dsc.o rc_calc.o rc_calc_dpi.o
As previously fixed for dml in commit 4769278e5c7f ("amdgpu/dc/dml: Support clang option for stack alignment") and calcs in commit cc32ad8f559c ("amdgpu/dc/calcs: Support clang option for stack alignment"), dcn20 uses an option that is not available with clang: clang: error: unknown argument: '-mpreferred-stack-boundary=4' scripts/Makefile.build:281: recipe for target 'drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_resource.o' failed Use the same trick that we have in the other two files. Fixes: 7ed4e6352c16 ("drm/amd/display: Add DCN2 HW Sequencer and Resource") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 8 +++++++- drivers/gpu/drm/amd/display/dc/dsc/Makefile | 16 ++++++++++++---- 2 files changed, 19 insertions(+), 5 deletions(-)