Revert "drm/amd/display: use ARCH_HAS_KERNEL_FPU_SUPPORT"

This reverts commit a28e4b6.

JIRA: https://issues.redhat.com/browse/RHEL-53570
Upstream Status: RHEL-only

Signed-off-by: Robert Foss <rfoss@redhat.com>

Author: Robert Foss

drivers/gpu/drm/amd/display/Kconfig

@@ -10,7 +10,7 @@ config DRM_AMD_DC
 	depends on BROKEN || !CC_IS_CLANG || ARM64 || RISCV || SPARC64 || X86_64
 	select SND_HDA_COMPONENT if SND_HDA_CORE
 	# !CC_IS_CLANG: https://github.com/ClangBuiltLinux/linux/issues/1752
-	select DRM_AMD_DC_FP if ARCH_HAS_KERNEL_FPU_SUPPORT && !(CC_IS_CLANG && (ARM64 || RISCV))
+	select DRM_AMD_DC_FP if (X86 || LOONGARCH || (PPC64 && ALTIVEC) || (ARM64 && KERNEL_MODE_NEON && !CC_IS_CLANG))
 	help
 	  Choose this option if you want to use the new display engine
 	  support for AMDGPU. This adds required support for Vega and

drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c

@@ -26,7 +26,16 @@
 
 #include "dc_trace.h"
 
-#include <linux/fpu.h>
+#if defined(CONFIG_X86)
+#include <asm/fpu/api.h>
+#elif defined(CONFIG_PPC64)
+#include <asm/switch_to.h>
+#include <asm/cputable.h>
+#elif defined(CONFIG_ARM64)
+#include <asm/neon.h>
+#elif defined(CONFIG_LOONGARCH)
+#include <asm/fpu.h>
+#endif
 
 /**
  * DOC: DC FPU manipulation overview
@@ -78,9 +87,16 @@ void dc_fpu_begin(const char *function_name, const int line)
 	WARN_ON_ONCE(!in_task());
 	preempt_disable();
 	depth = __this_cpu_inc_return(fpu_recursion_depth);
+
 	if (depth == 1) {
-		BUG_ON(!kernel_fpu_available());
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
 		kernel_fpu_begin();
+#elif defined(CONFIG_PPC64)
+		if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
+			enable_kernel_fp();
+#elif defined(CONFIG_ARM64)
+		kernel_neon_begin();
+#endif
 	}
 
 	TRACE_DCN_FPU(true, function_name, line, depth);
@@ -102,7 +118,14 @@ void dc_fpu_end(const char *function_name, const int line)
 
 	depth = __this_cpu_dec_return(fpu_recursion_depth);
 	if (depth == 0) {
+#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
 		kernel_fpu_end();
+#elif defined(CONFIG_PPC64)
+		if (!cpu_has_feature(CPU_FTR_FPU_UNAVAILABLE))
+			disable_kernel_fp();
+#elif defined(CONFIG_ARM64)
+		kernel_neon_end();
+#endif
 	} else {
 		WARN_ON_ONCE(depth < 0);
 	}

drivers/gpu/drm/amd/display/dc/dml/Makefile

@@ -25,8 +25,40 @@
 # It provides the general basic services required by other DAL
 # subcomponents.
 
-dml_ccflags := $(CC_FLAGS_FPU)
-dml_rcflags := $(CC_FLAGS_NO_FPU)
+ifdef CONFIG_X86
+dml_ccflags-$(CONFIG_CC_IS_GCC) := -mhard-float
+dml_ccflags := $(dml_ccflags-y) -msse
+endif
+
+ifdef CONFIG_PPC64
+dml_ccflags := -mhard-float
+endif
+
+ifdef CONFIG_ARM64
+dml_rcflags := -mgeneral-regs-only
+endif
+
+ifdef CONFIG_LOONGARCH
+dml_ccflags := -mfpu=64
+dml_rcflags := -msoft-float
+endif
+
+ifdef CONFIG_CC_IS_GCC
+ifneq ($(call gcc-min-version, 70100),y)
+IS_OLD_GCC = 1
+endif
+endif
+
+ifdef CONFIG_X86
+ifdef IS_OLD_GCC
+# Stack alignment mismatch, proceed with caution.
+# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
+# (8B stack alignment).
+dml_ccflags += -mpreferred-stack-boundary=4
+else
+dml_ccflags += -msse2
+endif
+endif
 
 ifneq ($(CONFIG_FRAME_WARN),0)
 ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y)

drivers/gpu/drm/amd/display/dc/dml2/Makefile

@@ -24,8 +24,40 @@
 #
 # Makefile for dml2.
 
-dml2_ccflags := $(CC_FLAGS_FPU)
-dml2_rcflags := $(CC_FLAGS_NO_FPU)
+ifdef CONFIG_X86
+dml2_ccflags-$(CONFIG_CC_IS_GCC) := -mhard-float
+dml2_ccflags := $(dml2_ccflags-y) -msse
+endif
+
+ifdef CONFIG_PPC64
+dml2_ccflags := -mhard-float
+endif
+
+ifdef CONFIG_ARM64
+dml2_rcflags := -mgeneral-regs-only
+endif
+
+ifdef CONFIG_LOONGARCH
+dml2_ccflags := -mfpu=64
+dml2_rcflags := -msoft-float
+endif
+
+ifdef CONFIG_CC_IS_GCC
+ifeq ($(call cc-ifversion, -lt, 0701, y), y)
+IS_OLD_GCC = 1
+endif
+endif
+
+ifdef CONFIG_X86
+ifdef IS_OLD_GCC
+# Stack alignment mismatch, proceed with caution.
+# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
+# (8B stack alignment).
+dml2_ccflags += -mpreferred-stack-boundary=4
+else
+dml2_ccflags += -msse2
+endif
+endif
 
 ifneq ($(CONFIG_FRAME_WARN),0)
 ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y)