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From:   Samuel Holland <samuel.holland@sifive.com>
To:     linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
        linux-riscv@lists.infradead.org,
        Christoph Hellwig <hch@infradead.org>
Cc:     linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
        linux-arch@vger.kernel.org,
        Samuel Holland <samuel.holland@sifive.com>
Subject: [RFC PATCH 10/12] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT
Date:   Thu,  7 Dec 2023 21:54:40 -0800
Message-ID: <20231208055501.2916202-11-samuel.holland@sifive.com>
In-Reply-To: <20231208055501.2916202-1-samuel.holland@sifive.com>
References: <20231208055501.2916202-1-samuel.holland@sifive.com>
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Now that all previously-supported architectures select
ARCH_HAS_KERNEL_FPU_SUPPORT, this code can depend on that symbol instead
of the existing list of architectures. It can also take advantage of the
common kernel-mode FPU API and method of adjusting CFLAGS.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---

 drivers/gpu/drm/amd/display/Kconfig           |  2 +-
 .../gpu/drm/amd/display/amdgpu_dm/dc_fpu.c    | 33 +----------------
 drivers/gpu/drm/amd/display/dc/dml/Makefile   | 36 ++-----------------
 drivers/gpu/drm/amd/display/dc/dml2/Makefile  | 36 ++-----------------
 4 files changed, 6 insertions(+), 101 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/Kconfig b/drivers/gpu/drm/amd/display/Kconfig
index 901d1961b739..5fcd4f778dc3 100644
--- a/drivers/gpu/drm/amd/display/Kconfig
+++ b/drivers/gpu/drm/amd/display/Kconfig
@@ -8,7 +8,7 @@ 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 (X86 || LOONGARCH || (PPC64 && ALTIVEC) || (ARM64 && KERNEL_MODE_NEON && !CC_IS_CLANG))
+	select DRM_AMD_DC_FP if ARCH_HAS_KERNEL_FPU_SUPPORT && (!ARM64 || !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
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
index 4ae4720535a5..b64f917174ca 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/dc_fpu.c
@@ -26,16 +26,7 @@
 
 #include "dc_trace.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
@@ -87,20 +78,9 @@ 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) {
-#if defined(CONFIG_X86) || defined(CONFIG_LOONGARCH)
+		BUG_ON(!kernel_fpu_available());
 		kernel_fpu_begin();
-#elif defined(CONFIG_PPC64)
-		if (cpu_has_feature(CPU_FTR_VSX_COMP))
-			enable_kernel_vsx();
-		else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP))
-			enable_kernel_altivec();
-		else 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);
@@ -122,18 +102,7 @@ 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_VSX_COMP))
-			disable_kernel_vsx();
-		else if (cpu_has_feature(CPU_FTR_ALTIVEC_COMP))
-			disable_kernel_altivec();
-		else 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);
 	}
diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
index ea7d60f9a9b4..5aad0f572ba3 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
@@ -25,40 +25,8 @@
 # It provides the general basic services required by other DAL
 # subcomponents.
 
-ifdef CONFIG_X86
-dml_ccflags-$(CONFIG_CC_IS_GCC) := -mhard-float
-dml_ccflags := $(dml_ccflags-y) -msse
-endif
-
-ifdef CONFIG_PPC64
-dml_ccflags := -mhard-float -maltivec
-endif
-
-ifdef CONFIG_ARM64
-dml_rcflags := -mgeneral-regs-only
-endif
-
-ifdef CONFIG_LOONGARCH
-dml_ccflags := -mfpu=64
-dml_rcflags := -msoft-float
-endif
-
-ifdef CONFIG_CC_IS_GCC
-ifneq ($(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
+dml_ccflags := $(CC_FLAGS_FPU)
+dml_rcflags := $(CC_FLAGS_NO_FPU)
 
 ifneq ($(CONFIG_FRAME_WARN),0)
 frame_warn_flag := -Wframe-larger-than=2048
diff --git a/drivers/gpu/drm/amd/display/dc/dml2/Makefile b/drivers/gpu/drm/amd/display/dc/dml2/Makefile
index acff3449b8d7..4f6c804a26ad 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dml2/Makefile
@@ -24,40 +24,8 @@
 #
 # Makefile for dml2.
 
-ifdef CONFIG_X86
-dml2_ccflags-$(CONFIG_CC_IS_GCC) := -mhard-float
-dml2_ccflags := $(dml2_ccflags-y) -msse
-endif
-
-ifdef CONFIG_PPC64
-dml2_ccflags := -mhard-float -maltivec
-endif
-
-ifdef CONFIG_ARM64
-dml2_rcflags := -mgeneral-regs-only
-endif
-
-ifdef CONFIG_LOONGARCH
-dml2_ccflags := -mfpu=64
-dml2_rcflags := -msoft-float
-endif
-
-ifdef CONFIG_CC_IS_GCC
-ifeq ($(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
+dml2_ccflags := $(CC_FLAGS_FPU)
+dml2_rcflags := $(CC_FLAGS_NO_FPU)
 
 ifneq ($(CONFIG_FRAME_WARN),0)
 ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y)
-- 
2.42.0