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drm/amd/display: readd -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines

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[ Upstream commit 0f0727d971f6fdf8f1077180d495ddb9928f0c8b ]

arch/x86/Makefile disables SSE and SSE2 for the whole kernel.  The
AMDGPU drivers modified in this patch re-enable SSE but not SSE2.  Turn
on SSE2 to support emitting double precision floating point instructions
rather than calls to non-existent (usually available from gcc_s or
compiler_rt) floating point helper routines for Clang.

This was originally landed in:
commit 10117450735c ("drm/amd/display: add -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines")
but reverted in:
commit 193392ed9f69 ("Revert "drm/amd/display: add -msse2 to prevent Clang from emitting libcalls to undefined SW FP routines"")
due to bugreports from GCC builds. Add guards to only do so for Clang.

Link: https://bugs.freedesktop.org/show_bug.cgi?id=109487
Link: https://github.com/ClangBuiltLinux/linux/issues/327

Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nick Desaulniers 2019-07-22 15:31:05 -07:00 committed by Greg Kroah-Hartman
parent 80fc27953e
commit 70ec2eecc5
2 changed files with 8 additions and 0 deletions
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4
drivers/gpu/drm/amd/display/dc/calcs/Makefile
View File

@ -32,6 +32,10 @@ endif
calcs_ccflags := -mhard-float -msse $(cc_stack_align)
ifdef CONFIG_CC_IS_CLANG
calcs_ccflags += -msse2
endif
CFLAGS_dcn_calcs.o := $(calcs_ccflags)
CFLAGS_dcn_calc_auto.o := $(calcs_ccflags)
CFLAGS_dcn_calc_math.o := $(calcs_ccflags) -Wno-tautological-compare

4
drivers/gpu/drm/amd/display/dc/dml/Makefile
View File

@ -32,6 +32,10 @@ endif
dml_ccflags := -mhard-float -msse $(cc_stack_align)
ifdef CONFIG_CC_IS_CLANG
dml_ccflags += -msse2
endif
CFLAGS_display_mode_lib.o := $(dml_ccflags)
CFLAGS_display_pipe_clocks.o := $(dml_ccflags)
CFLAGS_dml1_display_rq_dlg_calc.o := $(dml_ccflags)