From 0549828354c1707532b672c9e9d08ecc418c1421 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Wed, 16 Oct 2019 16:02:07 -0700 Subject: [PATCH 4308/4736] drm/amdgpu: fix stack alignment ABI mismatch for Clang The x86 kernel is compiled with an 8B stack alignment via `-mpreferred-stack-boundary=3` for GCC since 3.6-rc1 via commit d9b0cde91c60 ("x86-64, gcc: Use -mpreferred-stack-boundary=3 if supported") or `-mstack-alignment=8` for Clang. Parts of the AMDGPU driver are compiled with 16B stack alignment. Generally, the stack alignment is part of the ABI. Linking together two different translation units with differing stack alignment is dangerous, particularly when the translation unit with the smaller stack alignment makes calls into the translation unit with the larger stack alignment. While 8B aligned stacks are sometimes also 16B aligned, they are not always. Multiple users have reported General Protection Faults (GPF) when using the AMDGPU driver compiled with Clang. Clang is placing objects in stack slots assuming the stack is 16B aligned, and selecting instructions that require 16B aligned memory operands. At runtime, syscall handlers with 8B aligned stack call into code that assumes 16B stack alignment. When the stack is a multiple of 8B but not 16B, these instructions result in a GPF. Remove the code that added compatibility between the differing compiler flags, as it will result in runtime GPFs when built with Clang. Cleanups for GCC will be sent in later patches in the series. Link: https://github.com/ClangBuiltLinux/linux/issues/735 Tested-by: Shirish S Debugged-by: Yuxuan Shui Reported-by: Shirish S Reported-by: Yuxuan Shui Suggested-by: Andrew Cooper Signed-off-by: Nick Desaulniers Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/calcs/Makefile | 10 ++++------ drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 10 ++++------ drivers/gpu/drm/amd/display/dc/dcn21/Makefile | 10 ++++------ drivers/gpu/drm/amd/display/dc/dml/Makefile | 10 ++++------ drivers/gpu/drm/amd/display/dc/dsc/Makefile | 10 ++++------ 5 files changed, 20 insertions(+), 30 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/calcs/Makefile b/drivers/gpu/drm/amd/display/dc/calcs/Makefile index 16614d73a5fc..ab522ea992d2 100644 --- a/drivers/gpu/drm/amd/display/dc/calcs/Makefile +++ b/drivers/gpu/drm/amd/display/dc/calcs/Makefile @@ -24,13 +24,11 @@ # It calculates Bandwidth and Watermarks values for HW programming # -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 +calcs_ccflags := -mhard-float -msse -calcs_ccflags := -mhard-float -msse $(cc_stack_align) +ifdef CONFIG_CC_IS_GCC +calcs_ccflags += -mpreferred-stack-boundary=4 +endif ifdef CONFIG_CC_IS_CLANG calcs_ccflags += -msse2 diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile index f57a3b281408..a02e02980310 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dcn20/Makefile @@ -10,13 +10,11 @@ ifdef CONFIG_DRM_AMD_DC_DSC_SUPPORT DCN20 += dcn20_dsc.o endif -ifneq ($(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 -CFLAGS_dcn20_resource.o := -mhard-float -msse $(cc_stack_align) +ifdef CONFIG_CC_IS_GCC +CFLAGS_dcn20_resource.o += -mpreferred-stack-boundary=4 +endif ifdef CONFIG_CC_IS_CLANG CFLAGS_dcn20_resource.o += -msse2 diff --git a/drivers/gpu/drm/amd/display/dc/dcn21/Makefile b/drivers/gpu/drm/amd/display/dc/dcn21/Makefile index 4ddd4037c1f8..0fa857b69143 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn21/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dcn21/Makefile @@ -3,13 +3,11 @@ DCN21 = dcn21_hubp.o dcn21_hubbub.o dcn21_resource.o dcn21_hwseq.o dcn21_link_encoder.o -ifneq ($(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_dcn21_resource.o := -mhard-float -msse -CFLAGS_dcn21_resource.o := -mhard-float -msse $(cc_stack_align) +ifdef CONFIG_CC_IS_GCC +CFLAGS_dcn21_resource.o += -mpreferred-stack-boundary=4 +endif ifdef CONFIG_CC_IS_CLANG CFLAGS_dcn21_resource.o += -msse2 diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile index af2a864a6da0..b3db0900b473 100644 --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile @@ -24,13 +24,11 @@ # It provides the general basic services required by other DAL # subcomponents. -ifneq ($(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 +dml_ccflags := -mhard-float -msse -dml_ccflags := -mhard-float -msse $(cc_stack_align) +ifdef CONFIG_CC_IS_GCC +dml_ccflags += -mpreferred-stack-boundary=4 +endif ifdef CONFIG_CC_IS_CLANG dml_ccflags += -msse2 diff --git a/drivers/gpu/drm/amd/display/dc/dsc/Makefile b/drivers/gpu/drm/amd/display/dc/dsc/Makefile index 17db603f2d1f..4d18e2b60223 100644 --- a/drivers/gpu/drm/amd/display/dc/dsc/Makefile +++ b/drivers/gpu/drm/amd/display/dc/dsc/Makefile @@ -1,13 +1,11 @@ # # Makefile for the 'dsc' sub-component of DAL. -ifneq ($(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 -dsc_ccflags := -mhard-float -msse $(cc_stack_align) +ifdef CONFIG_CC_IS_GCC +dsc_ccflags += -mpreferred-stack-boundary=4 +endif ifdef CONFIG_CC_IS_CLANG dsc_ccflags += -msse2 -- 2.17.1